8282191: Implementation of Foreign Function & Memory API (Preview)

Reviewed-by: erikj, jvernee, psandoz, dholmes, mchung

make/conf/docs-modules.conf

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2014, 2022, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -55,7 +55,6 @@ DOCS_MODULES= \
     jdk.jsobject \
     jdk.jshell \
     jdk.jstatd \
-    jdk.incubator.foreign \
     jdk.localedata \
     jdk.management \
     jdk.management.agent \

make/conf/module-loader-map.conf

@@ -43,7 +43,6 @@ BOOT_MODULES= \
     java.rmi \
     java.security.sasl \
     java.xml \
-    jdk.incubator.foreign \
     jdk.incubator.vector \
     jdk.internal.vm.ci \
     jdk.jfr \

make/modules/java.base/Lib.gmk

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2011, 2021, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2011, 2022, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -203,3 +203,18 @@ ifeq ($(call isTargetOs, windows), true)
   ))
   TARGETS += $(COPY_TZMAPPINGS)
 endif
+
+################################################################################
+# Create system lookup
+
+$(eval $(call SetupJdkLibrary, BUILD_SYSLOOKUPLIB, \
+    NAME := syslookup, \
+    CFLAGS := $(CFLAGS_JDKLIB), \
+    CXXFLAGS := $(CXXFLAGS_JDKLIB), \
+    LDFLAGS := $(LDFLAGS_JDKLIB), \
+    LDFLAGS_linux := -Wl$(COMMA)--no-as-needed, \
+    LIBS := $(LIBCXX), \
+    LIBS_linux := -lc -lm -ldl, \
+))
+
+TARGETS += $(BUILD_SYSLOOKUPLIB)

make/modules/java.base/gensrc/GensrcVarHandles.gmk

@@ -160,14 +160,14 @@ endef
 ################################################################################
 
 ################################################################################
-# Setup a rule for generating a memory access var handle helper classes
+# Setup a rule for generating a memory segment var handle view class
 # Param 1 - Variable declaration prefix
 # Param 2 - Type with first letter capitalized
-define GenerateVarHandleMemoryAccess
+define GenerateVarHandleMemorySegment
 
   $1_Type := $2
 
-  $1_FILENAME := $(VARHANDLES_GENSRC_DIR)/MemoryAccessVarHandle$$($1_Type)Helper.java
+  $1_FILENAME := $(VARHANDLES_GENSRC_DIR)/VarHandleSegmentAs$$($1_Type)s.java
 
   ifeq ($$($1_Type), Byte)
     $1_type := byte
@@ -248,7 +248,7 @@ define GenerateVarHandleMemoryAccess
     $1_ARGS += -KfloatingPoint
   endif
 
-  $$($1_FILENAME): $(VARHANDLES_SRC_DIR)/X-VarHandleMemoryAccess.java.template $(BUILD_TOOLS_JDK)
+  $$($1_FILENAME): $(VARHANDLES_SRC_DIR)/X-VarHandleSegmentView.java.template $(BUILD_TOOLS_JDK)
 	$$(call MakeDir, $$(@D))
 	$(RM) $$@
 	$(TOOL_SPP) -nel -K$$($1_type) \
@@ -272,8 +272,8 @@ $(foreach t, $(VARHANDLES_BYTE_ARRAY_TYPES), \
   $(eval $(call GenerateVarHandleByteArray,VAR_HANDLE_BYTE_ARRAY_$t,$t)))
 
 # List the types to generate source for, with capitalized first letter
-VARHANDLES_MEMORY_ADDRESS_TYPES := Byte Short Char Int Long Float Double
+VARHANDLES_MEMORY_SEGMENT_TYPES := Byte Short Char Int Long Float Double
-$(foreach t, $(VARHANDLES_MEMORY_ADDRESS_TYPES), \
+$(foreach t, $(VARHANDLES_MEMORY_SEGMENT_TYPES), \
-  $(eval $(call GenerateVarHandleMemoryAccess,VAR_HANDLE_MEMORY_ADDRESS_$t,$t)))
+  $(eval $(call GenerateVarHandleMemorySegment,VAR_HANDLE_MEMORY_SEGMENT_$t,$t)))
 
 TARGETS += $(GENSRC_VARHANDLES)

make/modules/jdk.incubator.foreign/Lib.gmk

@@ -1,62 +0,0 @@
-#
-# Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
-# DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
-#
-# This code is free software; you can redistribute it and/or modify it
-# under the terms of the GNU General Public License version 2 only, as
-# published by the Free Software Foundation.  Oracle designates this
-# particular file as subject to the "Classpath" exception as provided
-# by Oracle in the LICENSE file that accompanied this code.
-#
-# This code is distributed in the hope that it will be useful, but WITHOUT
-# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-# version 2 for more details (a copy is included in the LICENSE file that
-# accompanied this code).
-#
-# You should have received a copy of the GNU General Public License version
-# 2 along with this work; if not, write to the Free Software Foundation,
-# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
-#
-# Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
-# or visit www.oracle.com if you need additional information or have any
-# questions.
-#
-
-include LibCommon.gmk
-
-ifeq ($(call isTargetOs, linux), true)
-
-  $(eval $(call SetupJdkLibrary, BUILD_SYSLOOKUPLIB, \
-      NAME := syslookup, \
-      CFLAGS := $(CFLAGS_JDKLIB), \
-      CXXFLAGS := $(CXXFLAGS_JDKLIB), \
-      LDFLAGS := $(LDFLAGS_JDKLIB) -Wl$(COMMA)--no-as-needed, \
-      LIBS := $(LIBCXX) -lc -lm -ldl, \
-  ))
-
-else ifeq ($(call isTargetOs, windows), false)
-
-  $(eval $(call SetupJdkLibrary, BUILD_SYSLOOKUPLIB, \
-      NAME := syslookup, \
-      CFLAGS := $(CFLAGS_JDKLIB), \
-      CXXFLAGS := $(CXXFLAGS_JDKLIB), \
-      LDFLAGS := $(LDFLAGS_JDKLIB), \
-      LIBS := $(LIBCXX), \
-  ))
-
-else # windows
-
-  $(eval $(call SetupJdkLibrary, BUILD_SYSLOOKUPLIB, \
-      NAME := WinFallbackLookup, \
-      CFLAGS := $(CFLAGS_JDKLIB), \
-      CXXFLAGS := $(CXXFLAGS_JDKLIB), \
-      LDFLAGS := $(LDFLAGS_JDKLIB), \
-      LIBS := $(LIBCXX), \
-  ))
-
-endif
-
-TARGETS += $(BUILD_SYSLOOKUPLIB)
-
-################################################################################

make/test/BuildMicrobenchmark.gmk

@@ -91,7 +91,7 @@ $(eval $(call SetupJavaCompilation, BUILD_JDK_MICROBENCHMARK, \
     TARGET_RELEASE := $(TARGET_RELEASE_NEWJDK_UPGRADED), \
     SMALL_JAVA := false, \
     CLASSPATH := $(MICROBENCHMARK_CLASSPATH), \
-    DISABLED_WARNINGS := processing rawtypes cast serial, \
+    DISABLED_WARNINGS := processing rawtypes cast serial preview, \
     SRC := $(MICROBENCHMARK_SRC), \
     BIN := $(MICROBENCHMARK_CLASSES), \
     JAVAC_FLAGS := --add-exports java.base/sun.security.util=ALL-UNNAMED \

make/test/JtregNativeJdk.gmk

@@ -69,14 +69,23 @@ ifeq ($(call isTargetOs, windows), true)
   BUILD_JDK_JTREG_EXECUTABLES_LIBS_exerevokeall := advapi32.lib
   BUILD_JDK_JTREG_LIBRARIES_CFLAGS_libAsyncStackWalk := /EHsc
   BUILD_JDK_JTREG_LIBRARIES_CFLAGS_libAsyncInvokers := /EHsc
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLinkerInvokerUnnamed := /EHsc
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLinkerInvokerModule := /EHsc
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLoaderLookupInvoker := /EHsc
   BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libAsyncStackWalk := $(LIBCXX)
   BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libAsyncInvokers := $(LIBCXX)
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLinkerInvokerUnnamed := $(LIBCXX)
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLinkerInvokerModule := $(LIBCXX)
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLoaderLookupInvoker := $(LIBCXX)
 else
   BUILD_JDK_JTREG_LIBRARIES_LIBS_libstringPlatformChars := -ljava
   BUILD_JDK_JTREG_LIBRARIES_LIBS_libDirectIO := -ljava
   BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libNativeThread := -pthread
   BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libAsyncStackWalk := $(LIBCXX) -pthread
   BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libAsyncInvokers := $(LIBCXX) -pthread
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLinkerInvokerUnnamed := $(LIBCXX) -pthread
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLinkerInvokerModule := $(LIBCXX) -pthread
+  BUILD_JDK_JTREG_LIBRARIES_LDFLAGS_libLoaderLookupInvoker := $(LIBCXX) -pthread
   BUILD_JDK_JTREG_EXCLUDE += exerevokeall.c
   ifeq ($(call isTargetOs, linux), true)
     BUILD_JDK_JTREG_LIBRARIES_LIBS_libInheritedChannel := -ljava

src/hotspot/share/ci/ciField.cpp

@@ -225,7 +225,7 @@ static bool trust_final_non_static_fields(ciInstanceKlass* holder) {
   // Even if general trusting is disabled, trust system-built closures in these packages.
   if (holder->is_in_package("java/lang/invoke") || holder->is_in_package("sun/invoke") ||
       holder->is_in_package("java/lang/reflect") || holder->is_in_package("jdk/internal/reflect") ||
-      holder->is_in_package("jdk/internal/foreign") || holder->is_in_package("jdk/incubator/foreign") ||
+      holder->is_in_package("jdk/internal/foreign") || holder->is_in_package("java/lang/foreign") ||
       holder->is_in_package("jdk/internal/vm/vector") || holder->is_in_package("jdk/incubator/vector") ||
       holder->is_in_package("java/lang"))
     return true;

src/hotspot/share/code/codeBlob.hpp

@@ -764,7 +764,6 @@ class OptimizedEntryBlob: public BufferBlob {
     JavaThread* thread;
     JNIHandleBlock* old_handles;
     JNIHandleBlock* new_handles;
-    bool should_detach;
   };
 
   // defined in frame_ARCH.cpp

src/hotspot/share/prims/scopedMemoryAccess.cpp

@@ -70,7 +70,6 @@ public:
 
 class CloseScopedMemoryClosure : public HandshakeClosure {
   jobject _deopt;
-  jobject _exception;
 
 public:
   jboolean _found;
@@ -78,7 +77,6 @@ public:
   CloseScopedMemoryClosure(jobject deopt, jobject exception)
     : HandshakeClosure("CloseScopedMemory")
     , _deopt(deopt)
-    , _exception(exception)
     , _found(false) {}
 
   void do_thread(Thread* thread) {
@@ -140,12 +138,11 @@ public:
 };
 
 /*
- * This function issues a global handshake operation with all
+ * This function performs a thread-local handshake against all threads running at the time
- * Java threads. This is useful for implementing asymmetric
+ * the given session (deopt) was closed. If the handshake for a given thread is processed while
- * dekker synchronization schemes, where expensive synchronization
+ * one or more threads is found inside a scoped method (that is, a method inside the ScopedMemoryAccess
- * in performance sensitive common paths, may be shifted to
+ * class annotated with the '@Scoped' annotation), and whose local variables mention the session being
- * a less common slow path instead.
+ * closed (deopt), this method returns false, signalling that the session cannot be closed safely.
- * Top frames containing obj will be deoptimized.
  */
 JVM_ENTRY(jboolean, ScopedMemoryAccess_closeScope(JNIEnv *env, jobject receiver, jobject deopt, jobject exception))
   CloseScopedMemoryClosure cl(deopt, exception);
@@ -155,26 +152,26 @@ JVM_END
 
 /// JVM_RegisterUnsafeMethods
 
-#define PKG "Ljdk/internal/misc/"
+#define PKG_MISC "Ljdk/internal/misc/"
+#define PKG_FOREIGN "Ljdk/internal/foreign/"
 
 #define MEMACCESS "ScopedMemoryAccess"
-#define SCOPE PKG MEMACCESS "$Scope;"
+#define SCOPE PKG_FOREIGN "MemorySessionImpl;"
-#define SCOPED_ERR PKG MEMACCESS "$Scope$ScopedAccessError;"
 
 #define CC (char*)  /*cast a literal from (const char*)*/
 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
 
 static JNINativeMethod jdk_internal_misc_ScopedMemoryAccess_methods[] = {
-    {CC "closeScope0",   CC "(" SCOPE SCOPED_ERR ")Z",           FN_PTR(ScopedMemoryAccess_closeScope)},
+    {CC "closeScope0",   CC "(" SCOPE ")Z",           FN_PTR(ScopedMemoryAccess_closeScope)},
 };
 
 #undef CC
 #undef FN_PTR
 
-#undef PKG
+#undef PKG_MISC
+#undef PKG_FOREIGN
 #undef MEMACCESS
 #undef SCOPE
-#undef SCOPED_EXC
 
 // This function is exported, used by NativeLookup.
 

src/hotspot/share/prims/universalUpcallHandler.cpp

@@ -36,6 +36,26 @@
 
 extern struct JavaVM_ main_vm;
 
+// When an upcall is invoked from a thread that is not attached to the VM, we need to attach it,
+// and then to detach it at some point later. Detaching a thread as soon as the upcall completes
+// is suboptimal, as the same thread could later upcall to Java again, at which point the VM would
+// create multiple Java views of the same native thread. For this reason, we use thread local storage
+// to keep track of the fact that we have attached a native thread to the VM. When the thread local
+// storage is destroyed (which happens when the native threads is terminated), we check if the
+// storage has an attached thread and, if so, we detach it from the VM.
+struct UpcallContext {
+  Thread* attachedThread;
+
+  ~UpcallContext() {
+    if (attachedThread != NULL) {
+      JavaVM_ *vm = (JavaVM *)(&main_vm);
+      vm->functions->DetachCurrentThread(vm);
+    }
+  }
+};
+
+APPROVED_CPP_THREAD_LOCAL UpcallContext threadContext;
+
 void ProgrammableUpcallHandler::upcall_helper(JavaThread* thread, jobject rec, address buff) {
   JavaThread* THREAD = thread; // For exception macros.
   ThreadInVMfromNative tiv(THREAD);
@@ -51,30 +71,23 @@ void ProgrammableUpcallHandler::upcall_helper(JavaThread* thread, jobject rec, a
   JavaCalls::call_static(&result, upcall_method.klass, upcall_method.name, upcall_method.sig, &args, CATCH);
 }
 
-JavaThread* ProgrammableUpcallHandler::maybe_attach_and_get_thread(bool* should_detach) {
+JavaThread* ProgrammableUpcallHandler::maybe_attach_and_get_thread() {
   JavaThread* thread = JavaThread::current_or_null();
   if (thread == nullptr) {
     JavaVM_ *vm = (JavaVM *)(&main_vm);
     JNIEnv* p_env = nullptr; // unused
-    jint result = vm->functions->AttachCurrentThread(vm, (void**) &p_env, nullptr);
+    jint result = vm->functions->AttachCurrentThreadAsDaemon(vm, (void**) &p_env, nullptr);
     guarantee(result == JNI_OK, "Could not attach thread for upcall. JNI error code: %d", result);
-    *should_detach = true;
     thread = JavaThread::current();
+    threadContext.attachedThread = thread;
     assert(!thread->has_last_Java_frame(), "newly-attached thread not expected to have last Java frame");
-  } else {
-    *should_detach = false;
   }
   return thread;
 }
 
-void ProgrammableUpcallHandler::detach_current_thread() {
-  JavaVM_ *vm = (JavaVM *)(&main_vm);
-  vm->functions->DetachCurrentThread(vm);
-}
-
 // modelled after JavaCallWrapper::JavaCallWrapper
 JavaThread* ProgrammableUpcallHandler::on_entry(OptimizedEntryBlob::FrameData* context) {
-  JavaThread* thread = maybe_attach_and_get_thread(&context->should_detach);
+  JavaThread* thread = maybe_attach_and_get_thread();
   context->thread = thread;
 
   assert(thread->can_call_java(), "must be able to call Java");
@@ -132,24 +145,15 @@ void ProgrammableUpcallHandler::on_exit(OptimizedEntryBlob::FrameData* context)
   JNIHandleBlock::release_block(context->new_handles, thread);
 
   assert(!thread->has_pending_exception(), "Upcall can not throw an exception");
-
-  if (context->should_detach) {
-    detach_current_thread();
-  }
 }
 
 void ProgrammableUpcallHandler::attach_thread_and_do_upcall(jobject rec, address buff) {
-  bool should_detach = false;
+  JavaThread* thread = maybe_attach_and_get_thread();
-  JavaThread* thread = maybe_attach_and_get_thread(&should_detach);
 
   {
     MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
     upcall_helper(thread, rec, buff);
   }
-
-  if (should_detach) {
-    detach_current_thread();
-  }
 }
 
 const ProgrammableUpcallHandler& ProgrammableUpcallHandler::instance() {

src/hotspot/share/prims/universalUpcallHandler.hpp

@@ -48,8 +48,7 @@ private:
   static void attach_thread_and_do_upcall(jobject rec, address buff);
 
   static void handle_uncaught_exception(oop exception);
-  static JavaThread* maybe_attach_and_get_thread(bool* should_detach);
+  static JavaThread* maybe_attach_and_get_thread();
-  static void detach_current_thread();
 
   static JavaThread* on_entry(OptimizedEntryBlob::FrameData* context);
   static void on_exit(OptimizedEntryBlob::FrameData* context);

src/java.base/share/classes/java/lang/foreign/AbstractLayout.java

@@ -0,0 +1,163 @@
+/*
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ *  This code is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 only, as
+ *  published by the Free Software Foundation.  Oracle designates this
+ *  particular file as subject to the "Classpath" exception as provided
+ *  by Oracle in the LICENSE file that accompanied this code.
+ *
+ *  This code is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  version 2 for more details (a copy is included in the LICENSE file that
+ *  accompanied this code).
+ *
+ *  You should have received a copy of the GNU General Public License version
+ *  2 along with this work; if not, write to the Free Software Foundation,
+ *  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *   Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ *  or visit www.oracle.com if you need additional information or have any
+ *  questions.
+ *
+ */
+package java.lang.foreign;
+
+import java.util.Objects;
+import java.util.Optional;
+import jdk.internal.foreign.Utils;
+import jdk.internal.vm.annotation.Stable;
+
+abstract non-sealed class AbstractLayout implements MemoryLayout {
+
+    private final long size;
+    final long alignment;
+    private final Optional<String> name;
+    @Stable
+    long cachedSize;
+
+    public AbstractLayout(long size, long alignment, Optional<String> name) {
+        this.size = size;
+        this.alignment = alignment;
+        this.name = name;
+    }
+
+    @Override
+    public AbstractLayout withName(String name) {
+        Objects.requireNonNull(name);
+        return dup(alignment, Optional.of(name));
+    }
+
+    @Override
+    public final Optional<String> name() {
+        return name;
+    }
+
+    abstract AbstractLayout dup(long alignment, Optional<String> name);
+
+    @Override
+    public AbstractLayout withBitAlignment(long alignmentBits) {
+        checkAlignment(alignmentBits);
+        return dup(alignmentBits, name);
+    }
+
+    void checkAlignment(long alignmentBitCount) {
+        if (((alignmentBitCount & (alignmentBitCount - 1)) != 0L) || //alignment must be a power of two
+                (alignmentBitCount < 8)) { //alignment must be greater than 8
+            throw new IllegalArgumentException("Invalid alignment: " + alignmentBitCount);
+        }
+    }
+
+    static void checkSize(long size) {
+        checkSize(size, false);
+    }
+
+    static void checkSize(long size, boolean includeZero) {
+        if (size < 0 || (!includeZero && size == 0)) {
+            throw new IllegalArgumentException("Invalid size for layout: " + size);
+        }
+    }
+
+    @Override
+    public final long bitAlignment() {
+        return alignment;
+    }
+
+    @Override
+    public long byteSize() {
+        if (cachedSize == 0) {
+            cachedSize = Utils.bitsToBytesOrThrow(bitSize(),
+                    () -> new UnsupportedOperationException("Cannot compute byte size; bit size is not a multiple of 8"));
+        }
+        return cachedSize;
+    }
+
+    @Override
+    public long bitSize() {
+        return size;
+    }
+
+    String decorateLayoutString(String s) {
+        if (name().isPresent()) {
+            s = String.format("%s(%s)", s, name().get());
+        }
+        if (!hasNaturalAlignment()) {
+            s = alignment + "%" + s;
+        }
+        return s;
+    }
+
+    boolean hasNaturalAlignment() {
+        return size == alignment;
+    }
+
+    @Override
+    public boolean isPadding() {
+        return this instanceof PaddingLayout;
+    }
+
+    /**
+     * {@return the hash code value for this layout}
+     */
+    @Override
+    public int hashCode() {
+        return name.hashCode() << Long.hashCode(alignment);
+    }
+
+    /**
+     * Compares the specified object with this layout for equality. Returns {@code true} if and only if the specified
+     * object is also a layout, and it is equal to this layout. Two layouts are considered equal if they are of
+     * the same kind, have the same size, name and alignment constraints. Furthermore, depending on the layout kind, additional
+     * conditions must be satisfied:
+     * <ul>
+     *     <li>two value layouts are considered equal if they have the same byte order (see {@link ValueLayout#order()})</li>
+     *     <li>two sequence layouts are considered equal if they have the same element count (see {@link SequenceLayout#elementCount()}), and
+     *     if their element layouts (see {@link SequenceLayout#elementLayout()}) are also equal</li>
+     *     <li>two group layouts are considered equal if they are of the same kind (see {@link GroupLayout#isStruct()},
+     *     {@link GroupLayout#isUnion()}) and if their member layouts (see {@link GroupLayout#memberLayouts()}) are also equal</li>
+     * </ul>
+     *
+     * @param that the object to be compared for equality with this layout.
+     * @return {@code true} if the specified object is equal to this layout.
+     */
+    @Override
+    public boolean equals(Object that) {
+        if (this == that) {
+            return true;
+        }
+
+        if (!(that instanceof AbstractLayout)) {
+            return false;
+        }
+
+        return Objects.equals(name, ((AbstractLayout) that).name) &&
+                Objects.equals(alignment, ((AbstractLayout) that).alignment);
+    }
+
+    /**
+     * {@return the string representation of this layout}
+     */
+    public abstract String toString();
+}

src/java.base/share/classes/java/lang/foreign/Addressable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,21 +23,22 @@
  * questions.
  */
 
-package jdk.incubator.foreign;
+package java.lang.foreign;
+
+import jdk.internal.javac.PreviewFeature;
 
 /**
- * Represents a type which is <em>addressable</em>. An addressable type is one which can be projected down to
+ * An object that may be projected down to a {@linkplain #address() memory address}.
- * a {@linkplain #address() memory address}. Examples of addressable types are {@link MemorySegment},
+ * Examples of addressable types are {@link MemorySegment}, {@link MemoryAddress} and {@link VaList}.
- * {@link MemoryAddress}, {@link VaList} and {@link NativeSymbol}.
  * <p>
- * The {@link Addressable} type is used by the {@link CLinker C linker} to model the types of
+ * The {@link Addressable} type is used by a {@linkplain Linker linker} to model the types of
- * {@link CLinker#downcallHandle(FunctionDescriptor) downcall handle} parameters that must be passed <em>by reference</em>
+ * {@linkplain Linker#downcallHandle(FunctionDescriptor) downcall handle} parameters that must be passed <em>by reference</em>
- * (e.g. memory addresses, va lists and upcall stubs).
+ * (e.g. memory addresses, variable argument lists and upcall stubs).
  *
- * @implSpec
+ * @since 19
- * Implementations of this interface are <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
  */
-public sealed interface Addressable permits MemorySegment, MemoryAddress, NativeSymbol, VaList {
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+public sealed interface Addressable permits MemorySegment, MemoryAddress, VaList {
 
     /**
      * {@return the {@linkplain MemoryAddress memory address} associated with this addressable}

src/java.base/share/classes/java/lang/foreign/FunctionDescriptor.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -22,28 +22,34 @@
  *  or visit www.oracle.com if you need additional information or have any
  *  questions.
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;
 
-import java.lang.constant.Constable;
+import java.lang.invoke.MethodHandle;
-import java.lang.constant.ConstantDesc;
-import java.lang.constant.ConstantDescs;
-import java.lang.constant.DynamicConstantDesc;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 import java.util.stream.Stream;
+import jdk.internal.javac.PreviewFeature;
 
 /**
  * A function descriptor is made up of zero or more argument layouts and zero or one return layout. A function descriptor
- * is used to model the signature of foreign functions.
+ * is used to model the signature of foreign functions when creating
+ * {@linkplain Linker#downcallHandle(Addressable, FunctionDescriptor) downcall method handles} or
+ * {@linkplain Linker#upcallStub(MethodHandle, FunctionDescriptor, MemorySession) upcall stubs}.
  *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
+ * @implSpec
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
+ * This class is immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
+ *
+ * @see MemoryLayout
+ * @since 19
  */
-public sealed class FunctionDescriptor implements Constable permits FunctionDescriptor.VariadicFunction {
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+public sealed class FunctionDescriptor permits FunctionDescriptor.VariadicFunction {
 
     private final MemoryLayout resLayout;
     private final List<MemoryLayout> argLayouts;
@@ -61,14 +67,14 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     }
 
     /**
-     * {@return the argument layouts associated with this function descriptor}.
+     * {@return the argument layouts associated with this function descriptor (as an immutable list)}.
      */
     public List<MemoryLayout> argumentLayouts() {
-        return argLayouts;
+        return Collections.unmodifiableList(argLayouts);
     }
 
     /**
-     * Create a function descriptor with given return and argument layouts.
+     * Creates a function descriptor with the given return and argument layouts.
      * @param resLayout the return layout.
      * @param argLayouts the argument layouts.
      * @return the new function descriptor.
@@ -81,7 +87,7 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     }
 
     /**
-     * Create a function descriptor with given argument layouts and no return layout.
+     * Creates a function descriptor with the given argument layouts and no return layout.
      * @param argLayouts the argument layouts.
      * @return the new function descriptor.
      */
@@ -92,13 +98,13 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     }
 
     /**
-     * Obtain a specialized variadic function descriptor, by appending given variadic layouts to this
+     * Creates a specialized variadic function descriptor, by appending given variadic layouts to this
      * function descriptor argument layouts. The resulting function descriptor can report the position
      * of the {@linkplain #firstVariadicArgumentIndex() first variadic argument}, and cannot be altered
      * in any way: for instance, calling {@link #changeReturnLayout(MemoryLayout)} on the resulting descriptor
      * will throw an {@link UnsupportedOperationException}.
      * @param variadicLayouts the variadic argument layouts to be appended to this descriptor argument layouts.
-     * @return a new variadic function descriptor, or this descriptor if {@code variadicLayouts.length == 0}.
+     * @return a variadic function descriptor, or this descriptor if {@code variadicLayouts.length == 0}.
      */
     public FunctionDescriptor asVariadic(MemoryLayout... variadicLayouts) {
         Objects.requireNonNull(variadicLayouts);
@@ -116,7 +122,7 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     }
 
     /**
-     * Create a new function descriptor with the given argument layouts appended to the argument layout array
+     * Returns a function descriptor with the given argument layouts appended to the argument layout array
      * of this function descriptor.
      * @param addedLayouts the argument layouts to append.
      * @return the new function descriptor.
@@ -126,7 +132,7 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     }
 
     /**
-     * Create a new function descriptor with the given argument layouts inserted at the given index, into the argument
+     * Returns a function descriptor with the given argument layouts inserted at the given index, into the argument
      * layout array of this function descriptor.
      * @param index the index at which to insert the arguments
      * @param addedLayouts the argument layouts to insert at given index.
@@ -145,7 +151,7 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     }
 
     /**
-     * Create a new function descriptor with the given memory layout as the new return layout.
+     * Returns a function descriptor with the given memory layout as the new return layout.
      * @param newReturn the new return layout.
      * @return the new function descriptor.
      */
@@ -155,7 +161,7 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     }
 
     /**
-     * Create a new function descriptor with the return layout dropped. This is useful to model functions
+     * Returns a function descriptor with the return layout dropped. This is useful to model functions
      * which return no values.
      * @return the new function descriptor.
      */
@@ -169,8 +175,9 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
     @Override
     public String toString() {
         return String.format("(%s)%s",
-                Stream.of(argLayouts)
+                IntStream.range(0, argLayouts.size())
-                        .map(Object::toString)
+                        .mapToObj(i -> (i == firstVariadicArgumentIndex() ?
+                                "..." : "") + argLayouts.get(i))
                         .collect(Collectors.joining()),
                 returnLayout().map(Object::toString).orElse("v"));
     }
@@ -179,8 +186,9 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
      * Compares the specified object with this function descriptor for equality. Returns {@code true} if and only if the specified
      * object is also a function descriptor, and all the following conditions are met:
      * <ul>
-     *     <li>the two function descriptors have equals return layouts (see {@link MemoryLayout#equals(Object)}), or both have no return layout</li>
+     *     <li>the two function descriptors have equals return layouts (see {@link MemoryLayout#equals(Object)}), or both have no return layout;</li>
-     *     <li>the two function descriptors have argument layouts that are pair-wise equal (see {@link MemoryLayout#equals(Object)})
+     *     <li>the two function descriptors have argument layouts that are pair-wise {@linkplain MemoryLayout#equals(Object) equal}; and</li>
+     *     <li>the two function descriptors have the same leading {@linkplain #firstVariadicArgumentIndex() variadic argument index}</li>
      * </ul>
      *
      * @param other the object to be compared for equality with this function descriptor.
@@ -188,13 +196,10 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
      */
     @Override
     public boolean equals(Object other) {
-        if (this == other) {
+        return other instanceof FunctionDescriptor f &&
-            return true;
+                Objects.equals(resLayout, f.resLayout) &&
-        }
+                Objects.equals(argLayouts, f.argLayouts) &&
-        if (!(other instanceof FunctionDescriptor f)) {
+                firstVariadicArgumentIndex() == f.firstVariadicArgumentIndex();
-            return false;
-        }
-        return Objects.equals(resLayout, f.resLayout) && Objects.equals(argLayouts, f.argLayouts);
     }
 
     /**
@@ -202,30 +207,7 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
      */
     @Override
     public int hashCode() {
-        int hashCode = Objects.hashCode(argLayouts);
+        return Objects.hash(argLayouts, resLayout, firstVariadicArgumentIndex());
-        return resLayout == null ? hashCode : resLayout.hashCode() ^ hashCode;
-    }
-
-    /**
-     * Returns an {@link Optional} containing the nominal descriptor for this
-     * function descriptor, if one can be constructed, or an empty {@link Optional}
-     * if one cannot be constructed.
-     *
-     * @return An {@link Optional} containing the resulting nominal descriptor,
-     * or an empty {@link Optional} if one cannot be constructed.
-     */
-    @Override
-    public Optional<DynamicConstantDesc<FunctionDescriptor>> describeConstable() {
-        List<ConstantDesc> constants = new ArrayList<>();
-        constants.add(resLayout == null ? AbstractLayout.MH_VOID_FUNCTION : AbstractLayout.MH_FUNCTION);
-        if (resLayout != null) {
-            constants.add(resLayout.describeConstable().get());
-        }
-        for (MemoryLayout argLayout : argLayouts) {
-            constants.add(argLayout.describeConstable().get());
-        }
-        return Optional.of(DynamicConstantDesc.ofNamed(
-                ConstantDescs.BSM_INVOKE, "function", AbstractLayout.CD_FUNCTION_DESC, constants.toArray(new ConstantDesc[0])));
     }
 
     static final class VariadicFunction extends FunctionDescriptor {
@@ -262,10 +244,5 @@ public sealed class FunctionDescriptor implements Constable permits FunctionDesc
         public FunctionDescriptor dropReturnLayout() {
             throw new UnsupportedOperationException();
         }
-
-        @Override
-        public Optional<DynamicConstantDesc<FunctionDescriptor>> describeConstable() {
-            return Optional.empty();
-        }
     }
 }

src/java.base/share/classes/java/lang/foreign/GroupLayout.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -23,39 +23,28 @@
  *  questions.
  *
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;
 
-import java.lang.constant.ConstantDesc;
-import java.lang.constant.ConstantDescs;
-import java.lang.constant.DynamicConstantDesc;
-import java.lang.constant.MethodHandleDesc;
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
-import java.util.OptionalLong;
 import java.util.function.LongBinaryOperator;
 import java.util.stream.Collectors;
+import jdk.internal.javac.PreviewFeature;
 
 /**
- * A group layout is used to combine multiple <em>member layouts</em>. There are two ways in which member layouts
+ * A compound layout that aggregates multiple <em>member layouts</em>. There are two ways in which member layouts
  * can be combined: if member layouts are laid out one after the other, the resulting group layout is said to be a <em>struct</em>
  * (see {@link MemoryLayout#structLayout(MemoryLayout...)}); conversely, if all member layouts are laid out at the same starting offset,
  * the resulting group layout is said to be a <em>union</em> (see {@link MemoryLayout#unionLayout(MemoryLayout...)}).
- * <p>
- * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
- * class; programmers should treat instances that are
- * {@linkplain #equals(Object) equal} as interchangeable and should not
- * use instances for synchronization, or unpredictable behavior may
- * occur. For example, in a future release, synchronization may fail.
- * The {@code equals} method should be used for comparisons.
- *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
  *
  * @implSpec
- * This class is immutable and thread-safe.
+ * This class is immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
+ *
+ * @since 19
  */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
 public final class GroupLayout extends AbstractLayout implements MemoryLayout {
 
     /**
@@ -65,32 +54,26 @@ public final class GroupLayout extends AbstractLayout implements MemoryLayout {
         /**
          * A 'struct' kind.
          */
-        STRUCT("", MH_STRUCT, Long::sum),
+        STRUCT("", Math::addExact),
         /**
          * A 'union' kind.
          */
-        UNION("|", MH_UNION, Math::max);
+        UNION("|", Math::max);
 
         final String delimTag;
-        final MethodHandleDesc mhDesc;
         final LongBinaryOperator sizeOp;
 
-        Kind(String delimTag, MethodHandleDesc mhDesc, LongBinaryOperator sizeOp) {
+        Kind(String delimTag, LongBinaryOperator sizeOp) {
             this.delimTag = delimTag;
-            this.mhDesc = mhDesc;
             this.sizeOp = sizeOp;
         }
 
-        OptionalLong sizeof(List<MemoryLayout> elems) {
+        long sizeof(List<MemoryLayout> elems) {
             long size = 0;
             for (MemoryLayout elem : elems) {
-                if (AbstractLayout.optSize(elem).isPresent()) {
                 size = sizeOp.applyAsLong(size, elem.bitSize());
-                } else {
-                    return OptionalLong.empty();
             }
-            }
+            return size;
-            return OptionalLong.of(size);
         }
 
         long alignof(List<MemoryLayout> elems) {
@@ -125,6 +108,9 @@ public final class GroupLayout extends AbstractLayout implements MemoryLayout {
         return Collections.unmodifiableList(elements);
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public String toString() {
         return decorateLayoutString(elements.stream()
@@ -133,19 +119,22 @@ public final class GroupLayout extends AbstractLayout implements MemoryLayout {
     }
 
     /**
-     * {@return {@code true}, if this group layout is a <em>struct</em>}
+     * {@return {@code true}, if this group layout is a struct layout}
      */
     public boolean isStruct() {
         return kind == Kind.STRUCT;
     }
 
     /**
-     * {@return {@code true}, if this group layout is a <em>union</em>}
+     * {@return {@code true}, if this group layout is a union layout}
      */
     public boolean isUnion() {
         return kind == Kind.UNION;
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public boolean equals(Object other) {
         if (this == other) {
@@ -160,6 +149,9 @@ public final class GroupLayout extends AbstractLayout implements MemoryLayout {
         return kind.equals(g.kind) && elements.equals(g.elements);
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
     public int hashCode() {
         return Objects.hash(super.hashCode(), kind, elements);
@@ -175,18 +167,6 @@ public final class GroupLayout extends AbstractLayout implements MemoryLayout {
         return alignment == kind.alignof(elements);
     }
 
-    @Override
-    public Optional<DynamicConstantDesc<GroupLayout>> describeConstable() {
-        ConstantDesc[] constants = new ConstantDesc[1 + elements.size()];
-        constants[0] = kind.mhDesc;
-        for (int i = 0 ; i < elements.size() ; i++) {
-            constants[i + 1] = elements.get(i).describeConstable().get();
-        }
-        return Optional.of(decorateLayoutConstant(DynamicConstantDesc.ofNamed(
-                    ConstantDescs.BSM_INVOKE, kind.name().toLowerCase(),
-                CD_GROUP_LAYOUT, constants)));
-    }
-
     //hack: the declarations below are to make javadoc happy; we could have used generics in AbstractLayout
     //but that causes issues with javadoc, see JDK-8224052
 

src/java.base/share/classes/java/lang/foreign/Linker.java

@@ -0,0 +1,307 @@
+/*
+ *  Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
+ *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ *  This code is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 only, as
+ *  published by the Free Software Foundation.  Oracle designates this
+ *  particular file as subject to the "Classpath" exception as provided
+ *  by Oracle in the LICENSE file that accompanied this code.
+ *
+ *  This code is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  version 2 for more details (a copy is included in the LICENSE file that
+ *  accompanied this code).
+ *
+ *  You should have received a copy of the GNU General Public License version
+ *  2 along with this work; if not, write to the Free Software Foundation,
+ *  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *   Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ *  or visit www.oracle.com if you need additional information or have any
+ *  questions.
+ *
+ */
+package java.lang.foreign;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodType;
+
+import jdk.internal.foreign.abi.SharedUtils;
+import jdk.internal.foreign.abi.aarch64.linux.LinuxAArch64Linker;
+import jdk.internal.foreign.abi.aarch64.macos.MacOsAArch64Linker;
+import jdk.internal.foreign.abi.x64.sysv.SysVx64Linker;
+import jdk.internal.foreign.abi.x64.windows.Windowsx64Linker;
+import jdk.internal.javac.PreviewFeature;
+import jdk.internal.reflect.CallerSensitive;
+import jdk.internal.reflect.Reflection;
+
+/**
+ * A linker provides access to foreign functions from Java code, and access to Java code from foreign functions.
+ * <p>
+ * Foreign functions typically reside in libraries that can be loaded on-demand. Each library conforms to
+ * a specific ABI (Application Binary Interface). An ABI is a set of calling conventions and data types associated with
+ * the compiler, OS, and processor where the library was built. For example, a C compiler on Linux/x64 usually
+ * builds libraries that conform to the SystemV ABI.
+ * <p>
+ * A linker has detailed knowledge of the calling conventions and data types used by a specific ABI.
+ * For any library which conforms to that ABI, the linker can mediate between Java code running
+ * in the JVM and foreign functions in the library. In particular:
+ * <ul>
+ * <li>A linker allows Java code to link against foreign functions, via
+ * {@linkplain #downcallHandle(Addressable, FunctionDescriptor) downcall method handles}; and</li>
+ * <li>A linker allows foreign functions to call Java method handles,
+ * via the generation of {@linkplain #upcallStub(MethodHandle, FunctionDescriptor, MemorySession) upcall stubs}.</li>
+ * </ul>
+ * In addition, a linker provides a way to look up foreign functions in libraries that conform to the ABI. Each linker
+ * chooses a set of libraries that are commonly used on the OS and processor combination associated with the ABI.
+ * For example, a linker for Linux/x64 might choose two libraries: {@code libc} and {@code libm}. The functions in these
+ * libraries are exposed via a {@linkplain #defaultLookup() symbol lookup}.
+ * <p>
+ * The {@link #nativeLinker()} method provides a linker for the ABI associated with the OS and processor where the Java runtime
+ * is currently executing. This linker also provides access, via its {@linkplain #defaultLookup() default lookup},
+ * to the native libraries loaded with the Java runtime.
+ *
+ * <h2><a id = "downcall-method-handles">Downcall method handles</a></h2>
+ *
+ * {@linkplain #downcallHandle(FunctionDescriptor) Linking a foreign function} is a process which requires a function descriptor,
+ * a set of memory layouts which, together, specify the signature of the foreign function to be linked, and returns,
+ * when complete, a downcall method handle, that is, a method handle that can be used to invoke the target foreign function.
+ * <p>
+ * The Java {@linkplain java.lang.invoke.MethodType method type} associated with the returned method handle is
+ * {@linkplain #downcallType(FunctionDescriptor) derived} from the argument and return layouts in the function descriptor.
+ * More specifically, given each layout {@code L} in the function descriptor, a corresponding carrier {@code C} is inferred,
+ * as described below:
+ * <ul>
+ * <li>if {@code L} is a {@link ValueLayout} with carrier {@code E} then there are two cases:
+ *     <ul>
+ *         <li>if {@code L} occurs in a parameter position and {@code E} is {@code MemoryAddress.class},
+ *         then {@code C = Addressable.class};</li>
+ *         <li>otherwise, {@code C = E};
+ *     </ul></li>
+ * <li>or, if {@code L} is a {@link GroupLayout}, then {@code C} is set to {@code MemorySegment.class}</li>
+ * </ul>
+ * <p>
+ * The downcall method handle type, derived as above, might be decorated by additional leading parameters,
+ * in the given order if both are present:
+ * <ul>
+ * <li>If the downcall method handle is created {@linkplain #downcallHandle(FunctionDescriptor) without specifying a target address},
+ * the downcall method handle type features a leading parameter of type {@link Addressable}, from which the
+ * address of the target foreign function can be derived.</li>
+ * <li>If the function descriptor's return layout is a group layout, the resulting downcall method handle accepts
+ * an additional leading parameter of type {@link SegmentAllocator}, which is used by the linker runtime to allocate the
+ * memory region associated with the struct returned by the downcall method handle.</li>
+ * </ul>
+ *
+ * <h2><a id = "upcall-stubs">Upcall stubs</a></h2>
+ *
+ * {@linkplain #upcallStub(MethodHandle, FunctionDescriptor, MemorySession) Creating an upcall stub} requires a method
+ * handle and a function descriptor; in this case, the set of memory layouts in the function descriptor
+ * specify the signature of the function pointer associated with the upcall stub.
+ * <p>
+ * The type of the provided method handle has to {@linkplain #upcallType(FunctionDescriptor) match} the Java
+ * {@linkplain java.lang.invoke.MethodType method type} associated with the upcall stub, which is derived from the argument
+ * and return layouts in the function descriptor. More specifically, given each layout {@code L} in the function descriptor,
+ * a corresponding carrier {@code C} is inferred, as described below:
+ * <ul>
+ * <li>If {@code L} is a {@link ValueLayout} with carrier {@code E} then there are two cases:
+ *     <ul>
+ *         <li>If {@code L} occurs in a return position and {@code E} is {@code MemoryAddress.class},
+ *         then {@code C = Addressable.class};</li>
+ *         <li>Otherwise, {@code C = E};
+ *     </ul></li>
+ * <li>Or, if {@code L} is a {@link GroupLayout}, then {@code C} is set to {@code MemorySegment.class}</li>
+ * </ul>
+ * Upcall stubs are modelled by instances of type {@link MemorySegment}; upcall stubs can be passed by reference to other
+ * downcall method handles (as {@link MemorySegment} implements the {@link Addressable} interface) and,
+ * when no longer required, they can be {@linkplain MemorySession#close() released}, via their associated {@linkplain MemorySession session}.
+ *
+ * <h2>Safety considerations</h2>
+ *
+ * Creating a downcall method handle is intrinsically unsafe. A symbol in a foreign library does not, in general,
+ * contain enough signature information (e.g. arity and types of foreign function parameters). As a consequence,
+ * the linker runtime cannot validate linkage requests. When a client interacts with a downcall method handle obtained
+ * through an invalid linkage request (e.g. by specifying a function descriptor featuring too many argument layouts),
+ * the result of such interaction is unspecified and can lead to JVM crashes. On downcall handle invocation,
+ * the linker runtime guarantees the following for any argument that is a memory resource {@code R} (of type {@link MemorySegment}
+ * or {@link VaList}):
+ * <ul>
+ *     <li>The memory session of {@code R} is {@linkplain MemorySession#isAlive() alive}. Otherwise, the invocation throws
+ *     {@link IllegalStateException};</li>
+ *     <li>The invocation occurs in same thread as the one {@linkplain MemorySession#ownerThread() owning} the memory session of {@code R},
+ *     if said session is confined. Otherwise, the invocation throws {@link IllegalStateException}; and</li>
+ *     <li>The memory session of {@code R} is {@linkplain MemorySession#whileAlive(Runnable) kept alive} (and cannot be closed) during the invocation.</li>
+ *</ul>
+ * <p>
+ * When creating upcall stubs the linker runtime validates the type of the target method handle against the provided
+ * function descriptor and report an error if any mismatch is detected. As for downcalls, JVM crashes might occur,
+ * if the foreign code casts the function pointer associated with an upcall stub to a type
+ * that is incompatible with the provided function descriptor. Moreover, if the target method
+ * handle associated with an upcall stub returns a {@linkplain MemoryAddress memory address}, clients must ensure
+ * that this address cannot become invalid after the upcall completes. This can lead to unspecified behavior,
+ * and even JVM crashes, since an upcall is typically executed in the context of a downcall method handle invocation.
+ *
+ * @implSpec
+ * Implementations of this interface are immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
+ *
+ * @since 19
+ */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+public sealed interface Linker permits Windowsx64Linker, SysVx64Linker, LinuxAArch64Linker, MacOsAArch64Linker {
+
+    /**
+     * Returns a linker for the ABI associated with the underlying native platform. The underlying native platform
+     * is the combination of OS and processor where the Java runtime is currently executing.
+     * <p>
+     * When interacting with the returned linker, clients must describe the signature of a foreign function using a
+     * {@link FunctionDescriptor function descriptor} whose argument and return layouts are specified as follows:
+     * <ul>
+     *     <li>Scalar types are modelled by a {@linkplain ValueLayout value layout} instance of a suitable carrier. Example
+     *     of scalar types in C are {@code int}, {@code long}, {@code size_t}, etc. The mapping between a scalar type
+     *     and its corresponding layout is dependent on the ABI of the returned linker;
+     *     <li>Composite types are modelled by a {@linkplain GroupLayout group layout}. Depending on the ABI of the
+     *     returned linker, additional {@linkplain MemoryLayout#paddingLayout(long) padding} member layouts might be required to conform
+     *     to the size and alignment constraints of a composite type definition in C (e.g. using {@code struct} or {@code union}); and</li>
+     *     <li>Pointer types are modelled by a {@linkplain ValueLayout value layout} instance with carrier {@link MemoryAddress}.
+     *     Examples of pointer types in C are {@code int**} and {@code int(*)(size_t*, size_t*)};</li>
+     * </ul>
+     * <p>
+     * Any layout not listed above is <em>unsupported</em>; function descriptors containing unsupported layouts
+     * will cause an {@link IllegalArgumentException} to be thrown, when used to create a
+     * {@link #downcallHandle(Addressable, FunctionDescriptor) downcall method handle} or an
+     * {@linkplain #upcallStub(MethodHandle, FunctionDescriptor, MemorySession) upcall stub}.
+     * <p>
+     * Variadic functions (e.g. a C function declared with a trailing ellipses {@code ...} at the end of the formal parameter
+     * list or with an empty formal parameter list) are not supported directly. However, it is possible to link a
+     * variadic function by using a {@linkplain FunctionDescriptor#asVariadic(MemoryLayout...) <em>variadic</em>}
+     * function descriptor, in which the specialized signature of a given variable arity callsite is described in full.
+     * Alternatively, where the foreign library allows it, clients might be able to interact with variadic functions by
+     * passing a trailing parameter of type {@link VaList} (e.g. as in {@code vsprintf}).
+     * <p>
+     * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
+     * Restricted methods are unsafe, and, if used incorrectly, their use might crash
+     * the JVM or, worse, silently result in memory corruption. Thus, clients should refrain from depending on
+     * restricted methods, and use safe and supported functionalities, where possible.
+     *
+     * @apiNote It is not currently possible to obtain a linker for a different combination of OS and processor.
+     * @implNote The libraries exposed by the {@linkplain #defaultLookup() default lookup} associated with the returned
+     * linker are the native libraries loaded in the process where the Java runtime is currently executing. For example,
+     * on Linux, these libraries typically include {@code libc}, {@code libm} and {@code libdl}.
+     *
+     * @return a linker for the ABI associated with the OS and processor where the Java runtime is currently executing.
+     * @throws UnsupportedOperationException if the underlying native platform is not supported.
+     * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
+     * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
+     */
+    @CallerSensitive
+    static Linker nativeLinker() {
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), Linker.class, "nativeLinker");
+        return SharedUtils.getSystemLinker();
+    }
+
+    /**
+     * Creates a method handle which can be used to call a target foreign function with the given signature and address.
+     * <p>
+     * If the provided method type's return type is {@code MemorySegment}, then the resulting method handle features
+     * an additional prefix parameter, of type {@link SegmentAllocator}, which will be used by the linker runtime
+     * to allocate structs returned by-value.
+     * <p>
+     * Calling this method is equivalent to the following code:
+     * {@snippet lang=java :
+     * linker.downcallHandle(function).bindTo(symbol);
+     * }
+     *
+     * @param symbol the address of the target function.
+     * @param function the function descriptor of the target function.
+     * @return a downcall method handle. The method handle type is <a href="CLinker.html#downcall-method-handles"><em>inferred</em></a>
+     * @throws IllegalArgumentException if the provided function descriptor is not supported by this linker.
+     * or if the symbol is {@link MemoryAddress#NULL}
+     */
+    default MethodHandle downcallHandle(Addressable symbol, FunctionDescriptor function) {
+        SharedUtils.checkSymbol(symbol);
+        return downcallHandle(function).bindTo(symbol);
+    }
+
+    /**
+     * Creates a method handle which can be used to call a target foreign function with the given signature.
+     * The resulting method handle features a prefix parameter (as the first parameter) corresponding to the foreign function
+     * entry point, of type {@link Addressable}, which is used to specify the address of the target function
+     * to be called.
+     * <p>
+     * If the provided function descriptor's return layout is a {@link GroupLayout}, then the resulting method handle features an
+     * additional prefix parameter (inserted immediately after the address parameter), of type {@link SegmentAllocator}),
+     * which will be used by the linker runtime to allocate structs returned by-value.
+     * <p>
+     * The returned method handle will throw an {@link IllegalArgumentException} if the {@link Addressable} parameter passed to it is
+     * associated with the {@link MemoryAddress#NULL} address, or a {@link NullPointerException} if that parameter is {@code null}.
+     *
+     * @param function the function descriptor of the target function.
+     * @return a downcall method handle. The method handle type is <a href="CLinker.html#downcall-method-handles"><em>inferred</em></a>
+     * from the provided function descriptor.
+     * @throws IllegalArgumentException if the provided function descriptor is not supported by this linker.
+     */
+    MethodHandle downcallHandle(FunctionDescriptor function);
+
+    /**
+     * Creates a stub which can be passed to other foreign functions as a function pointer, with the given
+     * memory session. Calling such a function pointer from foreign code will result in the execution of the provided
+     * method handle.
+     * <p>
+     * The returned memory segment's base address points to the newly allocated upcall stub, and is associated with
+     * the provided memory session. When such session is closed, the corresponding upcall stub will be deallocated.
+     * <p>
+     * The target method handle should not throw any exceptions. If the target method handle does throw an exception,
+     * the VM will exit with a non-zero exit code. To avoid the VM aborting due to an uncaught exception, clients
+     * could wrap all code in the target method handle in a try/catch block that catches any {@link Throwable}, for
+     * instance by using the {@link java.lang.invoke.MethodHandles#catchException(MethodHandle, Class, MethodHandle)}
+     * method handle combinator, and handle exceptions as desired in the corresponding catch block.
+     *
+     * @param target the target method handle.
+     * @param function the upcall stub function descriptor.
+     * @param session the upcall stub memory session.
+     * @return a zero-length segment whose base address is the address of the upcall stub.
+     * @throws IllegalArgumentException if the provided function descriptor is not supported by this linker.
+     * @throws IllegalArgumentException if it is determined that the target method handle can throw an exception, or if the target method handle
+     * has a type that does not match the upcall stub <a href="CLinker.html#upcall-stubs"><em>inferred type</em></a>.
+     * @throws IllegalStateException if {@code session} is not {@linkplain MemorySession#isAlive() alive}, or if access occurs from
+     * a thread other than the thread {@linkplain MemorySession#ownerThread() owning} {@code session}.
+     */
+    MemorySegment upcallStub(MethodHandle target, FunctionDescriptor function, MemorySession session);
+
+    /**
+     * Returns a symbol lookup for symbols in a set of commonly used libraries.
+     * <p>
+     * Each {@link Linker} is responsible for choosing libraries that are widely recognized as useful on the OS
+     * and processor combination supported by the {@link Linker}. Accordingly, the precise set of symbols exposed by the
+     * symbol lookup is unspecified; it varies from one {@link Linker} to another.
+     * @implNote It is strongly recommended that the result of {@link #defaultLookup} exposes a set of symbols that is stable over time.
+     * Clients of {@link #defaultLookup()} are likely to fail if a symbol that was previously exposed by the symbol lookup is no longer exposed.
+     * <p>If an implementer provides {@link Linker} implementations for multiple OS and processor combinations, then it is strongly
+     * recommended that the result of {@link #defaultLookup()} exposes, as much as possible, a consistent set of symbols
+     * across all the OS and processor combinations.
+     * @return a symbol lookup for symbols in a set of commonly used libraries.
+     */
+    SymbolLookup defaultLookup();
+
+    /**
+     * {@return the downcall method handle {@linkplain MethodType type} associated with the given function descriptor}
+     * @param functionDescriptor a function descriptor.
+     * @throws IllegalArgumentException if one or more layouts in the function descriptor are not supported
+     * (e.g. if they are sequence layouts or padding layouts).
+     */
+    static MethodType downcallType(FunctionDescriptor functionDescriptor) {
+        return SharedUtils.inferMethodType(functionDescriptor, false);
+    }
+
+    /**
+     * {@return the method handle {@linkplain MethodType type} associated with an upcall stub with the given function descriptor}
+     * @param functionDescriptor a function descriptor.
+     * @throws IllegalArgumentException if one or more layouts in the function descriptor are not supported
+     * (e.g. if they are sequence layouts or padding layouts).
+     */
+    static MethodType upcallType(FunctionDescriptor functionDescriptor) {
+        return SharedUtils.inferMethodType(functionDescriptor, true);
+    }
+}

src/java.base/share/classes/java/lang/foreign/MemoryAddress.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -24,30 +24,32 @@
  *
  */
 
-package jdk.incubator.foreign;
+package java.lang.foreign;
+
+import java.nio.ByteOrder;
 
 import jdk.internal.foreign.MemoryAddressImpl;
+import jdk.internal.javac.PreviewFeature;
 import jdk.internal.reflect.CallerSensitive;
 
 import java.lang.invoke.MethodHandle;
-import java.nio.ByteOrder;
 
 /**
  * A memory address models a reference into a memory location. Memory addresses are typically obtained in one of the following ways:
  * <ul>
  *     <li>By calling {@link Addressable#address()} on an instance of type {@link Addressable} (e.g. a memory segment);</li>
- *     <li>By invoking a {@linkplain CLinker#downcallHandle(FunctionDescriptor) downcall method handle} which returns a pointer;</li>
+ *     <li>By invoking a {@linkplain Linker#downcallHandle(FunctionDescriptor) downcall method handle} which returns a pointer;</li>
- *     <li>By reading an address from memory, e.g. via {@link MemorySegment#get(ValueLayout.OfAddress, long)}.</li>
+ *     <li>By reading an address from memory, e.g. via {@link MemorySegment#get(ValueLayout.OfAddress, long)}; and</li>
- *     <li>By the invocation of an {@linkplain CLinker#upcallStub(MethodHandle, FunctionDescriptor, ResourceScope) upcall stub} which accepts a pointer.
+ *     <li>By the invocation of an {@linkplain Linker#upcallStub(MethodHandle, FunctionDescriptor, MemorySession) upcall stub} which accepts a pointer.</li>
  * </ul>
  * A memory address is backed by a raw machine pointer, expressed as a {@linkplain #toRawLongValue() long value}.
  *
- * <h2>Dereference</h2>
+ * <h2>Dereferencing memory addresses</h2>
  *
  * A memory address can be read or written using various methods provided in this class (e.g. {@link #get(ValueLayout.OfInt, long)}).
- * Each dereference method takes a {@linkplain jdk.incubator.foreign.ValueLayout value layout}, which specifies the size,
+ * Each dereference method takes a {@linkplain ValueLayout value layout}, which specifies the size,
  * alignment constraints, byte order as well as the Java type associated with the dereference operation, and an offset.
- * For instance, to read an int from a segment, using {@link ByteOrder#nativeOrder() default endianness}, the following code can be used:
+ * For instance, to read an int from a segment, using {@linkplain ByteOrder#nativeOrder() default endianness}, the following code can be used:
  * {@snippet lang=java :
  * MemoryAddress address = ...
  * int value = address.get(ValueLayout.JAVA_INT, 0);
@@ -63,18 +65,13 @@ import java.nio.ByteOrder;
  * All the dereference methods in this class are <a href="package-summary.html#restricted"><em>restricted</em></a>: since
  * a memory address does not feature temporal nor spatial bounds, the runtime has no way to check the correctness
  * of the memory dereference operation.
- * <p>
- * All implementations of this interface must be <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>;
- * programmers should treat instances that are {@linkplain #equals(Object) equal} as interchangeable and should not
- * use instances for synchronization, or unpredictable behavior may occur. For example, in a future release,
- * synchronization may fail. The {@code equals} method should be used for comparisons.
- *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
  *
  * @implSpec
  * Implementations of this interface are immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
+ *
+ * @since 19
  */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
 public sealed interface MemoryAddress extends Addressable permits MemoryAddressImpl {
 
     /**
@@ -83,14 +80,15 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
     long toRawLongValue();
 
     /**
-     * Creates a new memory address with given offset (in bytes), which might be negative, from current one.
+     * Returns a memory address at given offset from this address.
      * @param offset specified offset (in bytes), relative to this address, which should be used to create the new address.
-     * @return a new memory address with given offset from current one.
+     *               Might be negative.
+     * @return a memory address with the given offset from current one.
      */
     MemoryAddress addOffset(long offset);
 
     /**
-     * Reads a UTF-8 encoded, null-terminated string from this address and offset.
+     * Reads a UTF-8 encoded, null-terminated string from this address at the given offset.
      * <p>
      * This method always replaces malformed-input and unmappable-character
      * sequences with this charset's default replacement string.  The {@link
@@ -102,28 +100,35 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * the JVM or, worse, silently result in memory corruption. Thus, clients should refrain from depending on
      * restricted methods, and use safe and supported functionalities, where possible.
      *
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a Java string constructed from the bytes read from the given starting address ({@code toRowLongValue() + offset})
      * up to (but not including) the first {@code '\0'} terminator character (assuming one is found).
-     * @throws IllegalArgumentException if the size of the native string is greater than the largest string supported by the platform.
+     * @throws IllegalArgumentException if the size of the UTF-8 string is greater than the largest string supported by the platform.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     String getUtf8String(long offset);
 
     /**
-     * Writes the given string to this address at given offset, converting it to a null-terminated byte sequence using UTF-8 encoding.
+     * Writes the given string to this address at the given offset, converting it to a null-terminated byte sequence using UTF-8 encoding.
      * <p>
      * This method always replaces malformed-input and unmappable-character
      * sequences with this charset's default replacement string.  The {@link
      * java.nio.charset.CharsetDecoder} class should be used when more control
      * over the decoding process is required.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * <p>
+     * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
+     * Restricted methods are unsafe, and, if used incorrectly, their use might crash
+     * the JVM or, worse, silently result in memory corruption. Thus, clients should refrain from depending on
+     * restricted methods, and use safe and supported functionalities, where possible.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @param str the Java string to be written at this address.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
@@ -146,14 +151,14 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
     int hashCode();
 
     /**
-     * The native memory address instance modelling the {@code NULL} address.
+     * The memory address instance modelling the {@code NULL} address.
      */
     MemoryAddress NULL = new MemoryAddressImpl(0L);
 
     /**
-     * Obtain a native memory address instance from given long address.
+     * Creates a memory address from the given long value.
-     * @param value the long address.
+     * @param value the long value representing a raw address.
-     * @return the new memory address instance.
+     * @return a memory address with the given raw long value.
      */
     static MemoryAddress ofLong(long value) {
         return value == 0 ?
@@ -162,7 +167,7 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
     }
 
     /**
-     * Reads a byte from this address and offset with given layout.
+     * Reads a byte at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -170,19 +175,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a byte value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     byte get(ValueLayout.OfByte layout, long offset);
 
     /**
-     * Writes a byte to this address instance and offset with given layout.
+     * Writes a byte at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -190,19 +196,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the byte value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfByte layout, long offset, byte value);
 
     /**
-     * Reads a boolean from this address and offset with given layout.
+     * Reads a boolean at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -210,19 +217,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a boolean value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     boolean get(ValueLayout.OfBoolean layout, long offset);
 
     /**
-     * Writes a boolean to this address instance and offset with given layout.
+     * Writes a boolean at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -230,19 +238,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the boolean value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfBoolean layout, long offset, boolean value);
 
     /**
-     * Reads a char from this address and offset with given layout.
+     * Reads a char at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -250,19 +259,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a char value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     char get(ValueLayout.OfChar layout, long offset);
 
     /**
-     * Writes a char to this address instance and offset with given layout.
+     * Writes a char at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -270,19 +280,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the char value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfChar layout, long offset, char value);
 
     /**
-     * Reads a short from this address and offset with given layout.
+     * Reads a short at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -290,19 +301,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a short value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     short get(ValueLayout.OfShort layout, long offset);
 
     /**
-     * Writes a short to this address instance and offset with given layout.
+     * Writes a short at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -310,19 +322,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the short value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfShort layout, long offset, short value);
 
     /**
-     * Reads an int from this address and offset with given layout.
+     * Reads an int at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -330,19 +343,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return an int value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     int get(ValueLayout.OfInt layout, long offset);
 
     /**
-     * Writes an int to this address instance and offset with given layout.
+     * Writes an int at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -350,19 +364,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the int value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfInt layout, long offset, int value);
 
     /**
-     * Reads a float from this address and offset with given layout.
+     * Reads a float at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -370,19 +385,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a float value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     float get(ValueLayout.OfFloat layout, long offset);
 
     /**
-     * Writes a float to this address instance and offset with given layout.
+     * Writes a float at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -390,19 +406,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the float value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfFloat layout, long offset, float value);
 
     /**
-     * Reads a long from this address and offset with given layout.
+     * Reads a long at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -410,19 +427,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a long value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     long get(ValueLayout.OfLong layout, long offset);
 
     /**
-     * Writes a long to this address instance and offset with given layout.
+     * Writes a long at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -430,19 +448,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the long value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfLong layout, long offset, long value);
 
     /**
-     * Reads a double from this address and offset with given layout.
+     * Reads a double at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -450,19 +469,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return a double value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     double get(ValueLayout.OfDouble layout, long offset);
 
     /**
-     * Writes a double to this address instance and offset with given layout.
+     * Writes a double at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -470,19 +490,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the double value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfDouble layout, long offset, double value);
 
     /**
-     * Reads an address from this address and offset with given layout.
+     * Reads an address at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -490,19 +511,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param offset offset in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this read operation can be expressed as {@code toRowLongValue() + offset}.
      * @return an address value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     MemoryAddress get(ValueLayout.OfAddress layout, long offset);
 
     /**
-     * Writes an address to this address instance and offset with given layout.
+     * Writes an address at the given offset from this address, with the given layout.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -510,19 +532,20 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param offset offset in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
+     * @param offset offset in bytes (relative to this address). Might be negative.
+     *               The final address of this write operation can be expressed as {@code toRowLongValue() + offset}.
      * @param value the address value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void set(ValueLayout.OfAddress layout, long offset, Addressable value);
 
     /**
-     * Reads a char from this address and index, scaled by given layout size.
+     * Reads a char from this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -530,20 +553,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param index index in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @return a char value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     char getAtIndex(ValueLayout.OfChar layout, long index);
 
     /**
-     * Writes a char to this address instance and index, scaled by given layout size.
+     * Writes a char to this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -551,20 +575,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param index index in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @param value the char value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void setAtIndex(ValueLayout.OfChar layout, long index, char value);
 
     /**
-     * Reads a short from this address and index, scaled by given layout size.
+     * Reads a short from this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -572,20 +597,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param index index in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @return a short value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     short getAtIndex(ValueLayout.OfShort layout, long index);
 
     /**
-     * Writes a short to this address instance and index, scaled by given layout size.
+     * Writes a short to this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -593,20 +619,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param index index in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @param value the short value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void setAtIndex(ValueLayout.OfShort layout, long index, short value);
 
     /**
-     * Reads an int from this address and index, scaled by given layout size.
+     * Reads an int from this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -614,20 +641,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param index index in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @return an int value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     int getAtIndex(ValueLayout.OfInt layout, long index);
 
     /**
-     * Writes an int to this address instance and index, scaled by given layout size.
+     * Writes an int to this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -635,20 +663,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param index index in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @param value the int value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void setAtIndex(ValueLayout.OfInt layout, long index, int value);
 
     /**
-     * Reads a float from this address and index, scaled by given layout size.
+     * Reads a float from this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -656,20 +685,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param index index in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @return a float value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     float getAtIndex(ValueLayout.OfFloat layout, long index);
 
     /**
-     * Writes a float to this address instance and index, scaled by given layout size.
+     * Writes a float to this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -677,20 +707,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param index index in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @param value the float value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void setAtIndex(ValueLayout.OfFloat layout, long index, float value);
 
     /**
-     * Reads a long from this address and index, scaled by given layout size.
+     * Reads a long from this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -698,20 +729,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param index index in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @return a long value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     long getAtIndex(ValueLayout.OfLong layout, long index);
 
     /**
-     * Writes a long to this address instance and index, scaled by given layout size.
+     * Writes a long to this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -719,20 +751,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param index index in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @param value the long value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void setAtIndex(ValueLayout.OfLong layout, long index, long value);
 
     /**
-     * Reads a double from this address and index, scaled by given layout size.
+     * Reads a double from this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -740,20 +773,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param index index in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @return a double value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     double getAtIndex(ValueLayout.OfDouble layout, long index);
 
     /**
-     * Writes a double to this address instance and index, scaled by given layout size.
+     * Writes a double to this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -761,20 +795,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param index index in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @param value the double value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     void setAtIndex(ValueLayout.OfDouble layout, long index, double value);
 
     /**
-     * Reads an address from this address and index, scaled by given layout size.
+     * Reads an address from this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -782,20 +817,21 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be read.
-     * @param index index in bytes (relative to this address). The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this read operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @return an address value read from this address.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
     MemoryAddress getAtIndex(ValueLayout.OfAddress layout, long index);
 
     /**
-     * Writes an address to this address instance and index, scaled by given layout size.
+     * Writes an address to this address at the given index, scaled by the given layout size.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -803,13 +839,14 @@ public sealed interface MemoryAddress extends Addressable permits MemoryAddressI
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param layout the layout of the memory region to be written.
-     * @param index index in bytes (relative to this address). The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
+     * @param index index in bytes (relative to this address). Might be negative.
+     *              The final address of this write operation can be expressed as {@code toRowLongValue() + (index * layout.byteSize())}.
      * @param value the address value to be written.
      * @throws IllegalArgumentException if the dereference operation is
      * <a href="MemorySegment.html#segment-alignment">incompatible with the alignment constraints</a> in the provided layout,
      * or if the layout alignment is greater than its size.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive

src/java.base/share/classes/java/lang/foreign/MemoryLayout.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -23,14 +23,8 @@
  *  questions.
  *
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;
 
-import jdk.internal.foreign.LayoutPath;
-import jdk.internal.foreign.LayoutPath.PathElementImpl.PathKind;
-import jdk.internal.foreign.Utils;
-
-import java.lang.constant.Constable;
-import java.lang.constant.DynamicConstantDesc;
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.VarHandle;
@@ -38,12 +32,15 @@ import java.nio.ByteOrder;
 import java.util.EnumSet;
 import java.util.Objects;
 import java.util.Optional;
-import java.util.OptionalLong;
 import java.util.Set;
 import java.util.function.Function;
-import java.util.function.UnaryOperator;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import jdk.internal.foreign.LayoutPath;
+import jdk.internal.foreign.LayoutPath.PathElementImpl.PathKind;
+import jdk.internal.foreign.Utils;
+import jdk.internal.javac.PreviewFeature;
 
 /**
  * A memory layout can be used to describe the contents of a memory segment.
@@ -56,7 +53,10 @@ import java.util.stream.Stream;
  * element layout (see {@link SequenceLayout}); a <em>group layout</em> denotes an aggregation of (typically) heterogeneous
  * member layouts (see {@link GroupLayout}).
  * <p>
- * For instance, consider the following struct declaration in C:
+ * Layouts can be optionally associated with a <em>name</em>. A layout name can be referred to when
+ * constructing <a href="MemoryLayout.html#layout-paths"><em>layout paths</em></a>.
+ * <p>
+ * Consider the following struct declaration in C:
  *
  * {@snippet lang=c :
  * typedef struct {
@@ -76,14 +76,6 @@ import java.util.stream.Stream;
  *     )
  * ).withName("TaggedValues");
  * }
- * <p>
- * All implementations of this interface must be <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>;
- * programmers should treat instances that are {@linkplain #equals(Object) equal} as interchangeable and should not
- * use instances for synchronization, or unpredictable behavior may occur. For example, in a future release,
- * synchronization may fail. The {@code equals} method should be used for comparisons.
- *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
  *
  * <h2><a id = "layout-align">Size, alignment and byte order</a></h2>
  *
@@ -91,9 +83,8 @@ import java.util.stream.Stream;
  * always has the same size in bits, regardless of the platform in which it is used. For derived layouts, the size is computed
  * as follows:
  * <ul>
- *     <li>for a <em>finite</em> sequence layout <em>S</em> whose element layout is <em>E</em> and size is L,
+ *     <li>for a sequence layout <em>S</em> whose element layout is <em>E</em> and size is <em>L</em>,
  *     the size of <em>S</em> is that of <em>E</em>, multiplied by <em>L</em></li>
- *     <li>the size of an <em>unbounded</em> sequence layout is <em>unknown</em></li>
  *     <li>for a group layout <em>G</em> with member layouts <em>M1</em>, <em>M2</em>, ... <em>Mn</em> whose sizes are
  *     <em>S1</em>, <em>S2</em>, ... <em>Sn</em>, respectively, the size of <em>G</em> is either <em>S1 + S2 + ... + Sn</em> or
  *     <em>max(S1, S2, ... Sn)</em> depending on whether the group is a <em>struct</em> or an <em>union</em>, respectively</li>
@@ -122,8 +113,7 @@ import java.util.stream.Stream;
  * <p>
  * Layout paths are for example useful in order to obtain {@linkplain MemoryLayout#bitOffset(PathElement...) offsets} of
  * arbitrarily nested layouts inside another layout, to quickly obtain a {@linkplain #varHandle(PathElement...) memory access handle}
- * corresponding to the selected layout, to {@linkplain #select(PathElement...) select} an arbitrarily nested layout inside
+ * corresponding to the selected layout, or to {@linkplain #select(PathElement...) select} an arbitrarily nested layout inside
- * another layout, or to {@link #map(UnaryOperator, PathElement...) transform} a nested layout element inside
  * another layout.
  * <p>
  * Such <em>layout paths</em> can be constructed programmatically using the methods in this class.
@@ -140,26 +130,11 @@ import java.util.stream.Stream;
  *                                          PathElement.groupElement("value"));
  * }
  *
- * And, we can also replace the layout named {@code value} with another layout, as follows:
- * {@snippet lang=java :
- * MemoryLayout taggedValuesWithHole = taggedValues.map(l -> MemoryLayout.paddingLayout(32),
- *                                             PathElement.sequenceElement(), PathElement.groupElement("value"));
- * }
- *
- * That is, the above declaration is identical to the following, more verbose one:
- * {@snippet lang=java :
- * MemoryLayout taggedValuesWithHole = MemoryLayout.sequenceLayout(5,
- *     MemoryLayout.structLayout(
- *         ValueLayout.JAVA_BYTE.withName("kind"),
- *         MemoryLayout.paddingLayout(32),
- *         MemoryLayout.paddingLayout(32)
- * ));
- * }
- *
  * Layout paths can feature one or more <em>free dimensions</em>. For instance, a layout path traversing
  * an unspecified sequence element (that is, where one of the path component was obtained with the
  * {@link PathElement#sequenceElement()} method) features an additional free dimension, which will have to be bound at runtime.
- * This is important when obtaining memory access var handle from layouts, as in the following code:
+ * This is important when obtaining a {@linkplain MethodHandles#memorySegmentViewVarHandle(ValueLayout) memory segment view var handle}
+ * from layouts, as in the following code:
  *
  * {@snippet lang=java :
  * VarHandle valueHandle = taggedValues.varHandle(PathElement.sequenceElement(),
@@ -168,7 +143,7 @@ import java.util.stream.Stream;
  *
  * Since the layout path constructed in the above example features exactly one free dimension (as it doesn't specify
  * <em>which</em> member layout named {@code value} should be selected from the enclosing sequence layout),
- * it follows that the memory access var handle {@code valueHandle} will feature an <em>additional</em> {@code long}
+ * it follows that the var handle {@code valueHandle} will feature an <em>additional</em> {@code long}
  * access coordinate.
  *
  * <p>A layout path with free dimensions can also be used to create an offset-computing method handle, using the
@@ -184,59 +159,37 @@ import java.util.stream.Stream;
  * long offset2 = (long) offsetHandle.invokeExact(2L); // 16
  * }
  *
- * <h2>Layout attributes</h2>
- *
- * Layouts can be optionally associated with a <em>name</em>. A layout name can be referred to when
- * constructing <a href="MemoryLayout.html#layout-paths"><em>layout paths</em></a>.
- *
  * @implSpec
  * Implementations of this interface are immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
- */
-public sealed interface MemoryLayout extends Constable permits AbstractLayout, SequenceLayout, GroupLayout, PaddingLayout, ValueLayout {
-
-    /**
-     * {@return an {@link Optional} containing the nominal descriptor for this
-     * layout, if one can be constructed, or an empty {@link Optional}
-     * if one cannot be constructed}
-     */
-    @Override
-    Optional<? extends DynamicConstantDesc<? extends MemoryLayout>> describeConstable();
-
-    /**
-     * Returns {@code true} if this layout has a specified size. A layout does not have a specified size if it is (or contains) a sequence layout whose
-     * size is unspecified (see {@link SequenceLayout#elementCount()}).
  *
-     * Value layouts (see {@link ValueLayout}) and padding layouts (see {@link MemoryLayout#paddingLayout(long)})
+ * @since 19
-     * <em>always</em> have a specified size, therefore this method always returns {@code true} in these cases.
-     *
-     * @return {@code true}, if this layout has a specified size.
  */
-    boolean hasSize();
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+public sealed interface MemoryLayout permits AbstractLayout, SequenceLayout, GroupLayout, PaddingLayout, ValueLayout {
 
     /**
      * {@return the layout size, in bits}
-     * @throws UnsupportedOperationException if the layout is, or contains, a sequence layout with unspecified size (see {@link SequenceLayout}).
      */
     long bitSize();
 
     /**
      * {@return the layout size, in bytes}
-     * @throws UnsupportedOperationException if the layout is, or contains, a sequence layout with unspecified size (see {@link SequenceLayout}),
+     * @throws UnsupportedOperationException if {@code bitSize()} is not a multiple of 8.
-     * or if {@code bitSize()} is not a multiple of 8.
      */
     long byteSize();
 
     /**
-     * {@return the <em>name</em> (if any) associated with this layout}
+     * {@return the name (if any) associated with this layout}
      * @see MemoryLayout#withName(String)
      */
     Optional<String> name();
 
     /**
-     * Creates a new layout which features the desired layout <em>name</em>.
+     * Returns a memory layout with the same size and alignment constraints as this layout,
+     * but with the specified name.
      *
      * @param name the layout name.
-     * @return a new layout which is the same as this layout, except for the <em>name</em> associated with it.
+     * @return a memory layout with the given name.
      * @see MemoryLayout#name()
      */
     MemoryLayout withName(String name);
@@ -282,16 +235,17 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
     }
 
     /**
-     * Creates a new layout which features the desired alignment constraint.
+     * Returns a memory layout with the same size and name as this layout,
+     * but with the specified alignment constraints (in bits).
      *
      * @param bitAlignment the layout alignment constraint, expressed in bits.
-     * @return a new layout which is the same as this layout, except for the alignment constraint associated with it.
+     * @return a memory layout with the given alignment constraints.
      * @throws IllegalArgumentException if {@code bitAlignment} is not a power of two, or if it's less than 8.
      */
     MemoryLayout withBitAlignment(long bitAlignment);
 
     /**
-     * Computes the offset, in bits, of the layout selected by a given layout path, where the path is considered rooted in this
+     * Computes the offset, in bits, of the layout selected by the given layout path, where the path is considered rooted in this
      * layout.
      *
      * @param elements the layout path elements.
@@ -299,18 +253,17 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      * @throws IllegalArgumentException if the layout path does not select any layout nested in this layout, or if the
      * layout path contains one or more path elements that select multiple sequence element indices
      * (see {@link PathElement#sequenceElement()} and {@link PathElement#sequenceElement(long, long)}).
-     * @throws UnsupportedOperationException if one of the layouts traversed by the layout path has unspecified size.
      * @throws NullPointerException if either {@code elements == null}, or if any of the elements
      * in {@code elements} is {@code null}.
      */
     default long bitOffset(PathElement... elements) {
-        return computePathOp(LayoutPath.rootPath(this, MemoryLayout::bitSize), LayoutPath::offset,
+        return computePathOp(LayoutPath.rootPath(this), LayoutPath::offset,
                 EnumSet.of(PathKind.SEQUENCE_ELEMENT, PathKind.SEQUENCE_RANGE), elements);
     }
 
     /**
      * Creates a method handle that can be used to compute the offset, in bits, of the layout selected
-     * by a given layout path, where the path is considered rooted in this layout.
+     * by the given layout path, where the path is considered rooted in this layout.
      *
      * <p>The returned method handle has a return type of {@code long}, and features as many {@code long}
      * parameter types as there are free dimensions in the provided layout path (see {@link PathElement#sequenceElement()}),
@@ -334,15 +287,14 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      * specified by the given layout path elements, when supplied with the missing sequence element indices.
      * @throws IllegalArgumentException if the layout path contains one or more path elements that select
      * multiple sequence element indices (see {@link PathElement#sequenceElement(long, long)}).
-     * @throws UnsupportedOperationException if one of the layouts traversed by the layout path has unspecified size.
      */
     default MethodHandle bitOffsetHandle(PathElement... elements) {
-        return computePathOp(LayoutPath.rootPath(this, MemoryLayout::bitSize), LayoutPath::offsetHandle,
+        return computePathOp(LayoutPath.rootPath(this), LayoutPath::offsetHandle,
                 EnumSet.of(PathKind.SEQUENCE_RANGE), elements);
     }
 
     /**
-     * Computes the offset, in bytes, of the layout selected by a given layout path, where the path is considered rooted in this
+     * Computes the offset, in bytes, of the layout selected by the given layout path, where the path is considered rooted in this
      * layout.
      *
      * @param elements the layout path elements.
@@ -350,8 +302,7 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      * @throws IllegalArgumentException if the layout path does not select any layout nested in this layout, or if the
      * layout path contains one or more path elements that select multiple sequence element indices
      * (see {@link PathElement#sequenceElement()} and {@link PathElement#sequenceElement(long, long)}).
-     * @throws UnsupportedOperationException if one of the layouts traversed by the layout path has unspecified size,
+     * @throws UnsupportedOperationException if {@code bitOffset(elements)} is not a multiple of 8.
-     * or if {@code bitOffset(elements)} is not a multiple of 8.
      * @throws NullPointerException if either {@code elements == null}, or if any of the elements
      * in {@code elements} is {@code null}.
      */
@@ -361,7 +312,7 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
 
     /**
      * Creates a method handle that can be used to compute the offset, in bytes, of the layout selected
-     * by a given layout path, where the path is considered rooted in this layout.
+     * by the given layout path, where the path is considered rooted in this layout.
      *
      * <p>The returned method handle has a return type of {@code long}, and features as many {@code long}
      * parameter types as there are free dimensions in the provided layout path (see {@link PathElement#sequenceElement()}),
@@ -389,7 +340,6 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      * specified by the given layout path elements, when supplied with the missing sequence element indices.
      * @throws IllegalArgumentException if the layout path contains one or more path elements that select
      * multiple sequence element indices (see {@link PathElement#sequenceElement(long, long)}).
-     * @throws UnsupportedOperationException if one of the layouts traversed by the layout path has unspecified size.
      */
     default MethodHandle byteOffsetHandle(PathElement... elements) {
         MethodHandle mh = bitOffsetHandle(elements);
@@ -398,10 +348,10 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
     }
 
     /**
-     * Creates a memory access var handle that can be used to dereference memory at the layout selected by a given layout path,
+     * Creates an access var handle that can be used to dereference memory at the layout selected by the given layout path,
      * where the path is considered rooted in this layout.
      * <p>
-     * The final memory location accessed by the returned memory access var handle can be computed as follows:
+     * The final memory location accessed by the returned var handle can be computed as follows:
      *
      * <blockquote><pre>{@code
      * address = base + offset
@@ -417,27 +367,27 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      *
      * where {@code x_1}, {@code x_2}, ... {@code x_n} are <em>dynamic</em> values provided as {@code long}
      * arguments, whereas {@code c_1}, {@code c_2}, ... {@code c_m} are <em>static</em> offset constants
-     * and {@code s_0}, {@code s_1}, ... {@code s_n} are <em>static</em> stride constants which are derived from
+     * and {@code s_1}, {@code s_2}, ... {@code s_n} are <em>static</em> stride constants which are derived from
      * the layout path.
      *
      * @apiNote the resulting var handle will feature an additional {@code long} access coordinate for every
      * unspecified sequence access component contained in this layout path. Moreover, the resulting var handle
-     * features certain <a href="MemoryHandles.html#memaccess-mode">access mode restrictions</a>, which are common to all memory access var handles.
+     * features certain <em>access mode restrictions</em>, which are common to all memory segment view handles.
      *
      * @param elements the layout path elements.
      * @return a var handle which can be used to dereference memory at the (possibly nested) layout selected by the layout path in {@code elements}.
-     * @throws UnsupportedOperationException if the layout path has one or more elements with incompatible alignment constraints,
+     * @throws UnsupportedOperationException if the layout path has one or more elements with incompatible alignment constraints.
-     * or if one of the layouts traversed by the layout path has unspecified size.
      * @throws IllegalArgumentException if the layout path in {@code elements} does not select a value layout (see {@link ValueLayout}).
+     * @see MethodHandles#memorySegmentViewVarHandle(ValueLayout)
      */
     default VarHandle varHandle(PathElement... elements) {
-        return computePathOp(LayoutPath.rootPath(this, MemoryLayout::bitSize), LayoutPath::dereferenceHandle,
+        return computePathOp(LayoutPath.rootPath(this), LayoutPath::dereferenceHandle,
                 Set.of(), elements);
     }
 
     /**
      * Creates a method handle which, given a memory segment, returns a {@linkplain MemorySegment#asSlice(long,long) slice}
-     * corresponding to the layout selected by a given layout path, where the path is considered rooted in this layout.
+     * corresponding to the layout selected by the given layout path, where the path is considered rooted in this layout.
      *
      * <p>The returned method handle has a return type of {@code MemorySegment}, features a {@code MemorySegment}
      * parameter as leading parameter representing the segment to be sliced, and features as many trailing {@code long}
@@ -455,7 +405,7 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      *
      * where {@code x_1}, {@code x_2}, ... {@code x_n} are <em>dynamic</em> values provided as {@code long}
      * arguments, whereas {@code c_1}, {@code c_2}, ... {@code c_m} are <em>static</em> offset constants
-     * and {@code s_0}, {@code s_1}, ... {@code s_n} are <em>static</em> stride constants which are derived from
+     * and {@code s_1}, {@code s_2}, ... {@code s_n} are <em>static</em> stride constants which are derived from
      * the layout path.
      *
      * <p>After the offset is computed, the returned segment is created as if by calling:
@@ -474,11 +424,10 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      * @throws UnsupportedOperationException if the size of the selected layout in bits is not a multiple of 8.
      */
     default MethodHandle sliceHandle(PathElement... elements) {
-        return computePathOp(LayoutPath.rootPath(this, MemoryLayout::bitSize), LayoutPath::sliceHandle,
+        return computePathOp(LayoutPath.rootPath(this), LayoutPath::sliceHandle,
                 Set.of(), elements);
     }
 
-
     /**
      * Selects the layout from a path rooted in this layout.
      *
@@ -489,30 +438,12 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      * (see {@link PathElement#sequenceElement(long)} and {@link PathElement#sequenceElement(long, long)}).
      */
     default MemoryLayout select(PathElement... elements) {
-        return computePathOp(LayoutPath.rootPath(this, l -> 0L), LayoutPath::layout,
+        return computePathOp(LayoutPath.rootPath(this), LayoutPath::layout,
-                EnumSet.of(PathKind.SEQUENCE_ELEMENT_INDEX, PathKind.SEQUENCE_RANGE), elements);
-    }
-
-    /**
-     * Creates a transformed copy of this layout where a selected layout, from a path rooted in this layout,
-     * is replaced with the result of applying the given operation.
-     *
-     * @param op the unary operation to be applied to the selected layout.
-     * @param elements the layout path elements.
-     * @return a new layout where the layout selected by the layout path in {@code elements},
-     * has been replaced by the result of applying {@code op} to the selected layout.
-     * @throws IllegalArgumentException if the layout path does not select any layout nested in this layout,
-     * or if the layout path contains one or more path elements that select one or more sequence element indices
-     * (see {@link PathElement#sequenceElement(long)} and {@link PathElement#sequenceElement(long, long)}).
-     */
-    default MemoryLayout map(UnaryOperator<MemoryLayout> op, PathElement... elements) {
-        Objects.requireNonNull(op);
-        return computePathOp(LayoutPath.rootPath(this, l -> 0L), path -> path.map(op),
                 EnumSet.of(PathKind.SEQUENCE_ELEMENT_INDEX, PathKind.SEQUENCE_RANGE), elements);
     }
 
     private static <Z> Z computePathOp(LayoutPath path, Function<LayoutPath, Z> finalizer,
-                                       Set<LayoutPath.PathElementImpl.PathKind> badKinds, PathElement... elements) {
+                                       Set<PathKind> badKinds, PathElement... elements) {
         Objects.requireNonNull(elements);
         for (PathElement e : elements) {
             LayoutPath.PathElementImpl pathElem = (LayoutPath.PathElementImpl)Objects.requireNonNull(e);
@@ -530,24 +461,24 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
     boolean isPadding();
 
     /**
-     * Instances of this class are used to form <a href="MemoryLayout.html#layout-paths"><em>layout paths</em></a>. There
+     * An element in a <a href="MemoryLayout.html#layout-paths"><em>layout path</em></a>. There
      * are two kinds of path elements: <em>group path elements</em> and <em>sequence path elements</em>. Group
-     * path elements are used to select a given named member layout within a {@link GroupLayout}. Sequence
+     * path elements are used to select a named member layout within a {@link GroupLayout}. Sequence
      * path elements are used to select a sequence element layout within a {@link SequenceLayout}; selection
      * of sequence element layout can be <em>explicit</em> (see {@link PathElement#sequenceElement(long)}) or
      * <em>implicit</em> (see {@link PathElement#sequenceElement()}). When a path uses one or more implicit
      * sequence path elements, it acquires additional <em>free dimensions</em>.
      *
-     * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
-     * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
-     *
      * @implSpec
-     * Implementations of this interface are immutable and thread-safe.
+     * Implementations of this interface are immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     sealed interface PathElement permits LayoutPath.PathElementImpl {
 
         /**
-         * Returns a path element which selects a member layout with given name from a given group layout.
+         * Returns a path element which selects a member layout with the given name in a group layout.
          * The path element returned by this method does not alter the number of free dimensions of any path
          * that is combined with such element.
          *
@@ -555,47 +486,49 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
          * method will select the first one; that is, the group element with the lowest offset from current path is selected.
          *
          * @param name the name of the group element to be selected.
-         * @return a path element which selects the group element with given name.
+         * @return a path element which selects the group element with the given name.
          */
         static PathElement groupElement(String name) {
             Objects.requireNonNull(name);
-            return new LayoutPath.PathElementImpl(LayoutPath.PathElementImpl.PathKind.GROUP_ELEMENT,
+            return new LayoutPath.PathElementImpl(PathKind.GROUP_ELEMENT,
                                                   path -> path.groupElement(name));
         }
 
         /**
-         * Returns a path element which selects the element layout at the specified position in a given the sequence layout.
+         * Returns a path element which selects the element layout at the specified position in a sequence layout.
          * The path element returned by this method does not alter the number of free dimensions of any path
          * that is combined with such element.
          *
          * @param index the index of the sequence element to be selected.
-         * @return a path element which selects the sequence element layout with given index.
+         * @return a path element which selects the sequence element layout with the given index.
          * @throws IllegalArgumentException if {@code index < 0}.
          */
         static PathElement sequenceElement(long index) {
             if (index < 0) {
                 throw new IllegalArgumentException("Index must be positive: " + index);
             }
-            return new LayoutPath.PathElementImpl(LayoutPath.PathElementImpl.PathKind.SEQUENCE_ELEMENT_INDEX,
+            return new LayoutPath.PathElementImpl(PathKind.SEQUENCE_ELEMENT_INDEX,
                                                   path -> path.sequenceElement(index));
         }
 
         /**
-         * Returns a path element which selects the element layout in a <em>range</em> of positions in a given the sequence layout,
+         * Returns a path element which selects the element layout in a <em>range</em> of positions in a sequence layout.
-         * where the range is expressed as a pair of starting index (inclusive) {@code S} and step factor (which can also be negative)
+         * The range is expressed as a pair of starting index (inclusive) {@code S} and step factor (which can also be negative)
          * {@code F}.
          * If a path with free dimensions {@code n} is combined with the path element returned by this method,
          * the number of free dimensions of the resulting path will be {@code 1 + n}. If the free dimension associated
          * with this path is bound by an index {@code I}, the resulting accessed offset can be obtained with the following
          * formula:
+         *
          * <blockquote><pre>{@code
          * E * (S + I * F)
          * }</pre></blockquote>
+         *
          * where {@code E} is the size (in bytes) of the sequence element layout.
          *
          * @param start the index of the first sequence element to be selected.
          * @param step the step factor at which subsequence sequence elements are to be selected.
-         * @return a path element which selects the sequence element layout with given index.
+         * @return a path element which selects the sequence element layout with the given index.
          * @throws IllegalArgumentException if {@code start < 0}, or {@code step == 0}.
          */
         static PathElement sequenceElement(long start, long step) {
@@ -605,19 +538,19 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
             if (step == 0) {
                 throw new IllegalArgumentException("Step must be != 0: " + step);
             }
-            return new LayoutPath.PathElementImpl(LayoutPath.PathElementImpl.PathKind.SEQUENCE_RANGE,
+            return new LayoutPath.PathElementImpl(PathKind.SEQUENCE_RANGE,
                                                   path -> path.sequenceElement(start, step));
         }
 
         /**
-         * Returns a path element which selects an unspecified element layout from a given sequence layout.
+         * Returns a path element which selects an unspecified element layout in a sequence layout.
          * If a path with free dimensions {@code n} is combined with the path element returned by this method,
          * the number of free dimensions of the resulting path will be {@code 1 + n}.
          *
          * @return a path element which selects an unspecified sequence element layout.
          */
         static PathElement sequenceElement() {
-            return new LayoutPath.PathElementImpl(LayoutPath.PathElementImpl.PathKind.SEQUENCE_ELEMENT,
+            return new LayoutPath.PathElementImpl(PathKind.SEQUENCE_ELEMENT,
                                                   LayoutPath::sequenceElement);
         }
     }
@@ -652,7 +585,7 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
     String toString();
 
     /**
-     * Create a new padding layout with given size.
+     * Creates a padding layout with the given size.
      *
      * @param size the padding size in bits.
      * @return the new selector layout.
@@ -679,7 +612,7 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
      * </ul>
      * @param carrier the value layout carrier.
      * @param order the value layout's byte order.
-     * @return a new value layout.
+     * @return a value layout with the given Java carrier and byte-order.
      * @throws IllegalArgumentException if the carrier type is not supported.
      */
     static ValueLayout valueLayout(Class<?> carrier, ByteOrder order) {
@@ -709,48 +642,55 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
     }
 
     /**
-     * Create a new sequence layout with given element layout and element count.
+     * Creates a sequence layout with the given element layout and element count. If the element count has the
+     * special value {@code -1}, the element count is inferred to be the biggest possible count such that
+     * the sequence layout size does not overflow, using the following formula:
      *
-     * @param elementCount the sequence element count.
+     * <blockquote><pre>{@code
+     * inferredElementCount = Long.MAX_VALUE / elementLayout.bitSize();
+     * }</pre></blockquote>
+     *
+     * @param elementCount the sequence element count; if set to {@code -1}, the sequence element count is inferred.
      * @param elementLayout the sequence element layout.
-     * @return the new sequence layout with given element layout and size.
+     * @return the new sequence layout with the given element layout and size.
-     * @throws IllegalArgumentException if {@code elementCount < 0}.
+     * @throws IllegalArgumentException if {@code elementCount < -1}.
+     * @throws IllegalArgumentException if {@code elementCount != -1} and the computation {@code elementCount * elementLayout.bitSize()} overflows.
      */
     static SequenceLayout sequenceLayout(long elementCount, MemoryLayout elementLayout) {
+        if (elementCount == -1) {
+            // inferred element count
+            long inferredElementCount = Long.MAX_VALUE / elementLayout.bitSize();
+            return new SequenceLayout(inferredElementCount, elementLayout);
+        } else {
+            // explicit element count
             AbstractLayout.checkSize(elementCount, true);
-        OptionalLong size = OptionalLong.of(elementCount);
+            return wrapOverflow(() ->
-        return new SequenceLayout(size, Objects.requireNonNull(elementLayout));
+                    new SequenceLayout(elementCount, Objects.requireNonNull(elementLayout)));
+        }
     }
 
     /**
-     * Create a new sequence layout, with unbounded element count and given element layout.
+     * Creates a struct layout with the given member layouts.
      *
-     * @param elementLayout the element layout of the sequence layout.
+     * @param elements The member layouts of the struct layout.
-     * @return the new sequence layout with given element layout.
+     * @return a struct layout with the given member layouts.
-     */
+     * @throws IllegalArgumentException if the sum of the {@linkplain #bitSize() bit sizes} of the member layouts
-    static SequenceLayout sequenceLayout(MemoryLayout elementLayout) {
+     * overflows.
-        return new SequenceLayout(OptionalLong.empty(), Objects.requireNonNull(elementLayout));
-    }
-
-    /**
-     * Create a new <em>struct</em> group layout with given member layouts.
-     *
-     * @param elements The member layouts of the <em>struct</em> group layout.
-     * @return a new <em>struct</em> group layout with given member layouts.
      */
     static GroupLayout structLayout(MemoryLayout... elements) {
         Objects.requireNonNull(elements);
-        return new GroupLayout(GroupLayout.Kind.STRUCT,
+        return wrapOverflow(() ->
+                new GroupLayout(GroupLayout.Kind.STRUCT,
                         Stream.of(elements)
                                 .map(Objects::requireNonNull)
-                        .collect(Collectors.toList()));
+                                .collect(Collectors.toList())));
     }
 
     /**
-     * Create a new <em>union</em> group layout with given member layouts.
+     * Creates a union layout with the given member layouts.
      *
-     * @param elements The member layouts of the <em>union</em> layout.
+     * @param elements The member layouts of the union layout.
-     * @return a new <em>union</em> group layout with given member layouts.
+     * @return a union layout with the given member layouts.
      */
     static GroupLayout unionLayout(MemoryLayout... elements) {
         Objects.requireNonNull(elements);
@@ -759,4 +699,12 @@ public sealed interface MemoryLayout extends Constable permits AbstractLayout, S
                         .map(Objects::requireNonNull)
                         .collect(Collectors.toList()));
     }
+
+    private static <L extends MemoryLayout> L wrapOverflow(Supplier<L> layoutSupplier) {
+        try {
+            return layoutSupplier.get();
+        } catch (ArithmeticException ex) {
+            throw new IllegalArgumentException("Layout size exceeds Long.MAX_VALUE");
+        }
+    }
 }

src/java.base/share/classes/java/lang/foreign/MemorySession.java

@@ -0,0 +1,282 @@
+/*
+ * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.lang.foreign;
+
+import java.lang.ref.Cleaner;
+import java.util.Objects;
+
+import jdk.internal.foreign.MemorySessionImpl;
+import jdk.internal.javac.PreviewFeature;
+
+/**
+ * A memory session manages the lifecycle of one or more resources. Resources (e.g. {@link MemorySegment}) associated
+ * with a memory session can only be accessed while the memory session is {@linkplain #isAlive() alive},
+ * and by the {@linkplain #ownerThread() thread} associated with the memory session (if any).
+ * <p>
+ * Memory sessions can be closed. When a memory session is closed, it is no longer {@linkplain #isAlive() alive},
+ * and subsequent operations on resources associated with that session (e.g. attempting to access a {@link MemorySegment} instance)
+ * will fail with {@link IllegalStateException}.
+ * <p>
+ * A memory session is associated with one or more {@linkplain #addCloseAction(Runnable) close actions}. Close actions
+ * can be used to specify the cleanup code that must run when a given resource (or set of resources) is no longer in use.
+ * When a memory session is closed, the {@linkplain #addCloseAction(Runnable) close actions}
+ * associated with that session are executed (in unspecified order). For instance, closing the memory session associated with
+ * one or more {@linkplain MemorySegment#allocateNative(long, long, MemorySession) native memory segments} results in releasing
+ * the off-heap memory associated with said segments.
+ * <p>
+ * The {@linkplain #global() global session} is a memory session that cannot be closed.
+ * As a result, resources associated with the global session are never released. Examples of resources associated with
+ * the global memory session are {@linkplain MemorySegment#ofArray(int[]) heap segments}.
+ *
+ * <h2><a id = "thread-confinement">Thread confinement</a></h2>
+ *
+ * Memory sessions can be divided into two categories: <em>thread-confined</em> memory sessions, and <em>shared</em>
+ * memory sessions.
+ * <p>
+ * Confined memory sessions, support strong thread-confinement guarantees. Upon creation,
+ * they are assigned an {@linkplain #ownerThread() owner thread}, typically the thread which initiated the creation operation.
+ * After creating a confined memory session, only the owner thread will be allowed to directly manipulate the resources
+ * associated with this memory session. Any attempt to perform resource access from a thread other than the
+ * owner thread will fail with {@link IllegalStateException}.
+ * <p>
+ * Shared memory sessions, on the other hand, have no owner thread; as such, resources associated with shared memory sessions
+ * can be accessed by multiple threads. This might be useful when multiple threads need to access the same resource concurrently
+ * (e.g. in the case of parallel processing).
+ *
+ * <h2>Closeable memory sessions</h2>
+ *
+ * When a session is associated with off-heap resources, it is often desirable for said resources to be released in a timely fashion,
+ * rather than waiting for the session to be deemed <a href="../../../java/lang/ref/package.html#reachability">unreachable</a>
+ * by the garbage collector. In this scenario, a client might consider using a {@linkplain #isCloseable() <em>closeable</em>} memory session.
+ * Closeable memory sessions are memory sessions that can be {@linkplain MemorySession#close() closed} deterministically, as demonstrated
+ * in the following example:
+ *
+ * {@snippet lang=java :
+ * try (MemorySession session = MemorySession.openConfined()) {
+ *    MemorySegment segment1 = MemorySegment.allocateNative(100);
+ *    MemorySegment segment1 = MemorySegment.allocateNative(200);
+ *    ...
+ * } // all memory released here
+ * }
+ *
+ * The above code creates a confined, closeable session. Then it allocates two segments associated with that session.
+ * When the session is {@linkplain #close() closed} (above, this is done implicitly, using the <em>try-with-resources construct</em>),
+ * all memory allocated within the session will be released
+ * <p>
+ * Closeable memory sessions, while powerful, must be used with caution. Closeable memory sessions must be closed
+ * when no longer in use, either explicitly (by calling the {@link #close} method), or implicitly (by wrapping the use of
+ * a closeable memory session in a <em>try-with-resources construct</em>). A failure to do so might result in memory leaks.
+ * To mitigate this problem, closeable memory sessions can be associated with a {@link Cleaner} instance,
+ * so that they are also closed automatically, once the session instance becomes <a href="../../../java/lang/ref/package.html#reachability">unreachable</a>.
+ * This can be useful to allow for predictable, deterministic resource deallocation, while still preventing accidental
+ * native memory leaks. In case a client closes a memory session managed by a cleaner, no further action will be taken when
+ * the session becomes unreachable; that is, {@linkplain #addCloseAction(Runnable) close actions} associated with a
+ * memory session, whether managed or not, are called <em>exactly once</em>.
+ *
+ * <h2>Non-closeable views</h2>
+ *
+ * There are situations in which it might not be desirable for a memory session to be reachable from one or
+ * more resources associated with it. For instance, an API might create a private memory session, and allocate
+ * a memory segment, and then expose one or more slices of this segment to its clients. Since the API's memory session
+ * would be reachable from the slices (using the {@link MemorySegment#session()} accessor), it might be possible for
+ * clients to compromise the API (e.g. by closing the session prematurely). To avoid leaking private memory sessions
+ * to untrusted clients, an API can instead return segments based on a non-closeable view of the session it created, as follows:
+ *
+ * {@snippet lang=java :
+ * MemorySession session = MemorySession.openConfined();
+ * MemorySession nonCloseableSession = session.asNonCloseable();
+ * MemorySegment segment = MemorySegment.allocateNative(100, nonCloseableSession);
+ * segment.session().close(); // throws
+ * session.close(); //ok
+ * }
+ *
+ * In other words, only the owner of the original {@code session} object can close the session. External clients can only
+ * access the non-closeable session, and have no access to the underlying API session.
+ *
+ * @implSpec
+ * Implementations of this interface are thread-safe.
+ *
+ * @see MemorySegment
+ * @see SymbolLookup
+ * @see Linker
+ * @see VaList
+ *
+ * @since 19
+ */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+public sealed interface MemorySession extends AutoCloseable, SegmentAllocator permits MemorySessionImpl, MemorySessionImpl.NonCloseableView {
+
+    /**
+     * {@return {@code true}, if this memory session is alive}
+     */
+    boolean isAlive();
+
+    /**
+     * {@return {@code true}, if this session is a closeable memory session}.
+     */
+    boolean isCloseable();
+
+    /**
+     * {@return the owner thread associated with this memory session, or {@code null} if this session is shared
+     * across multiple threads}
+     */
+    Thread ownerThread();
+
+    /**
+     * Runs a critical action while this memory session is kept alive.
+     * @param action the action to be run.
+     */
+    void whileAlive(Runnable action);
+
+    /**
+     * Adds a custom cleanup action which will be executed when the memory session is closed.
+     * The order in which custom cleanup actions are invoked once the memory session is closed is unspecified.
+     * @apiNote The provided action should not keep a strong reference to this memory session, so that implicitly
+     * closed sessions can be handled correctly by a {@link Cleaner} instance.
+     * @param runnable the custom cleanup action to be associated with this memory session.
+     * @throws IllegalStateException if this memory session is not {@linkplain #isAlive() alive}, or if access occurs from
+     * a thread other than the thread {@linkplain #ownerThread() owning} this memory session.
+     */
+    void addCloseAction(Runnable runnable);
+
+    /**
+     * Closes this memory session. If this operation completes without exceptions, this session
+     * will be marked as <em>not alive</em>, the {@linkplain #addCloseAction(Runnable) close actions} associated
+     * with this session will be executed, and all the resources associated with this session will be released.
+     *
+     * @apiNote This operation is not idempotent; that is, closing an already closed memory session <em>always</em> results in an
+     * exception being thrown. This reflects a deliberate design choice: memory session state transitions should be
+     * manifest in the client code; a failure in any of these transitions reveals a bug in the underlying application
+     * logic.
+     *
+     * @see MemorySession#isAlive()
+     *
+     * @throws IllegalStateException if this memory session is not {@linkplain #isAlive() alive}, or if access occurs from
+     * a thread other than the thread {@linkplain #ownerThread() owning} this memory session.
+     * @throws IllegalStateException if this session is {@linkplain #whileAlive(Runnable) kept alive} by another client.
+     * @throws UnsupportedOperationException if this memory session is not {@linkplain #isCloseable() closeable}.
+     */
+    void close();
+
+    /**
+     * Returns a non-closeable view of this memory session. If this session is {@linkplain #isCloseable() non-closeable},
+     * this session is returned. Otherwise, this method returns a non-closeable view of this memory session.
+     * @apiNote a non-closeable view of a memory session {@code S} keeps {@code S} reachable. As such, {@code S}
+     * cannot be closed implicitly (e.g. by a {@link Cleaner}) as long as one or more non-closeable views of {@code S}
+     * are reachable.
+     * @return a non-closeable view of this memory session.
+     */
+    MemorySession asNonCloseable();
+
+    /**
+     * Compares the specified object with this memory session for equality. Returns {@code true} if and only if the specified
+     * object is also a memory session, and it refers to the same memory session as this memory session.
+     * {@linkplain #asNonCloseable() A non-closeable view} {@code V} of a memory session {@code S} is considered
+     * equal to {@code S}.
+     *
+     * @param that the object to be compared for equality with this memory session.
+     * @return {@code true} if the specified object is equal to this memory session.
+     */
+    @Override
+    boolean equals(Object that);
+
+    /**
+     * {@return the hash code value for this memory session}
+     */
+    @Override
+    int hashCode();
+
+    /**
+     * Allocates a native segment, using this session. Equivalent to the following code:
+     * {@snippet lang=java :
+     * MemorySegment.allocateNative(size, align, this);
+     * }
+     *
+     * @throws IllegalStateException if this memory session is not {@linkplain #isAlive() alive}, or if access occurs from
+     * a thread other than the thread {@linkplain #ownerThread() owning} this memory session.
+     * @return a new native segment, associated with this session.
+     */
+    @Override
+    default MemorySegment allocate(long bytesSize, long bytesAlignment) {
+        return MemorySegment.allocateNative(bytesSize, bytesAlignment, this);
+    }
+
+    /**
+     * Creates a closeable confined memory session.
+     * @return a new closeable confined memory session.
+     */
+    static MemorySession openConfined() {
+        return MemorySessionImpl.createConfined(Thread.currentThread(), null);
+    }
+
+    /**
+     * Creates a closeable confined memory session, managed by the provided cleaner instance.
+     * @param cleaner the cleaner to be associated with the returned memory session.
+     * @return a new closeable confined memory session, managed by {@code cleaner}.
+     */
+    static MemorySession openConfined(Cleaner cleaner) {
+        Objects.requireNonNull(cleaner);
+        return MemorySessionImpl.createConfined(Thread.currentThread(), cleaner);
+    }
+
+    /**
+     * Creates a closeable shared memory session.
+     * @return a new closeable shared memory session.
+     */
+    static MemorySession openShared() {
+        return MemorySessionImpl.createShared(null);
+    }
+
+    /**
+     * Creates a closeable shared memory session, managed by the provided cleaner instance.
+     * @param cleaner the cleaner to be associated with the returned memory session.
+     * @return a new closeable shared memory session, managed by {@code cleaner}.
+     */
+    static MemorySession openShared(Cleaner cleaner) {
+        Objects.requireNonNull(cleaner);
+        return MemorySessionImpl.createShared(cleaner);
+    }
+
+    /**
+     * Creates a non-closeable shared memory session, managed by a private {@link Cleaner} instance.
+     * Equivalent to (but likely more efficient than) the following code:
+     * {@snippet lang=java :
+     * openShared(Cleaner.create()).asNonCloseable();
+     * }
+     * @return a non-closeable shared memory session, managed by a private {@link Cleaner} instance.
+     */
+    static MemorySession openImplicit() {
+        return MemorySessionImpl.createImplicit();
+    }
+
+    /**
+     * Returns the global memory session.
+     * @return the global memory session.
+     */
+    static MemorySession global() {
+        return MemorySessionImpl.GLOBAL;
+    }
+}

src/java.base/share/classes/java/lang/foreign/PaddingLayout.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -23,30 +23,17 @@
  *  questions.
  *
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;
 
-import java.lang.constant.ConstantDescs;
-import java.lang.constant.DynamicConstantDesc;
 import java.util.Objects;
 import java.util.Optional;
-import java.util.OptionalLong;
 
 /**
  * A padding layout. A padding layout specifies the size of extra space which is typically not accessed by applications,
  * and is typically used for aligning member layouts around word boundaries.
- * <p>
- * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
- * class; programmers should treat instances that are
- * {@linkplain #equals(Object) equal} as interchangeable and should not
- * use instances for synchronization, or unpredictable behavior may
- * occur. For example, in a future release, synchronization may fail.
- * The {@code equals} method should be used for comparisons.
- *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
  *
  * @implSpec
- * This class is immutable and thread-safe.
+ * This class is immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
  */
 /* package-private */ final class PaddingLayout extends AbstractLayout implements MemoryLayout {
 
@@ -55,7 +42,7 @@ import java.util.OptionalLong;
     }
 
     PaddingLayout(long size, long alignment, Optional<String> name) {
-        super(OptionalLong.of(size), alignment, name);
+        super(size, alignment, name);
     }
 
     @Override
@@ -92,12 +79,6 @@ import java.util.OptionalLong;
         return true;
     }
 
-    @Override
-    public Optional<DynamicConstantDesc<MemoryLayout>> describeConstable() {
-        return Optional.of(decorateLayoutConstant(DynamicConstantDesc.ofNamed(ConstantDescs.BSM_INVOKE, "padding",
-                CD_MEMORY_LAYOUT, MH_PADDING, bitSize())));
-    }
-
     //hack: the declarations below are to make javadoc happy; we could have used generics in AbstractLayout
     //but that causes issues with javadoc, see JDK-8224052
 

src/java.base/share/classes/java/lang/foreign/SegmentAllocator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,12 +23,7 @@
  * questions.
  */
 
-package jdk.incubator.foreign;
+package java.lang.foreign;
-
-import jdk.internal.foreign.AbstractMemorySegmentImpl;
-import jdk.internal.foreign.ArenaAllocator;
-import jdk.internal.foreign.ResourceScopeImpl;
-import jdk.internal.foreign.Utils;
 
 import java.lang.invoke.VarHandle;
 import java.lang.reflect.Array;
@@ -36,33 +31,36 @@ import java.nio.ByteOrder;
 import java.nio.charset.StandardCharsets;
 import java.util.Objects;
 import java.util.function.Function;
+import jdk.internal.foreign.AbstractMemorySegmentImpl;
+import jdk.internal.foreign.ArenaAllocator;
+import jdk.internal.foreign.Utils;
+import jdk.internal.javac.PreviewFeature;
 
 /**
- * This interface models a memory allocator. Clients implementing this interface
+ * An object that may be used to allocate {@linkplain MemorySegment memory segments}. Clients implementing this interface
  * must implement the {@link #allocate(long, long)} method. This interface defines several default methods
  * which can be useful to create segments from several kinds of Java values such as primitives and arrays.
- * This interface can be seen as a thin wrapper around the basic capabilities for
+ * This interface is a {@linkplain FunctionalInterface functional interface}: clients can easily obtain a new segment allocator
- * {@linkplain MemorySegment#allocateNative(long, long, ResourceScope) creating} native segments;
+ * by using either a lambda expression or a method reference.
- * since {@link SegmentAllocator} is a <em>functional interface</em>,
- * clients can easily obtain a native allocator by using either a lambda expression or a method reference.
  * <p>
  * This interface also defines factories for commonly used allocators:
  * <ul>
- *     <li>{@link #nativeAllocator(ResourceScope)} creates an allocator which
+ *     <li>{@link #newNativeArena(MemorySession)} creates a more efficient arena-style allocator, where off-heap memory
- *     {@linkplain MemorySegment#allocateNative(long, long, ResourceScope) allocates} native segments, backed by a given scope;</li>
- *     <li>{@link #newNativeArena(ResourceScope)} creates a more efficient arena-style native allocator, where memory
  *     is allocated in bigger blocks, which are then sliced accordingly to fit allocation requests;</li>
- *     <li>{@link #prefixAllocator(MemorySegment)} creates an allocator which wraps a segment (either on-heap or off-heap)
+ *     <li>{@link #implicitAllocator()} obtains an allocator which allocates native memory segment in independent,
+ *     {@linkplain MemorySession#openImplicit() implicit memory sessions}; and</li>
+ *     <li>{@link #prefixAllocator(MemorySegment)} obtains an allocator which wraps a segment (either on-heap or off-heap)
  *     and recycles its content upon each new allocation request.</li>
  * </ul>
  * <p>
  * Passing a segment allocator to an API can be especially useful in circumstances where a client wants to communicate <em>where</em>
  * the results of a certain operation (performed by the API) should be stored, as a memory segment. For instance,
- * {@linkplain CLinker#downcallHandle(FunctionDescriptor) downcall method handles} can accept an additional
+ * {@linkplain Linker#downcallHandle(FunctionDescriptor) downcall method handles} can accept an additional
- * {@link SegmentAllocator} parameter if the underlying native function is known to return a struct by-value. Effectively,
+ * {@link SegmentAllocator} parameter if the underlying foreign function is known to return a struct by-value. Effectively,
- * the allocator parameter tells the linker runtime where to store the return value of the native function.
+ * the allocator parameter tells the linker runtime where to store the return value of the foreign function.
  */
 @FunctionalInterface
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
 public interface SegmentAllocator {
 
     /**
@@ -85,7 +83,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given byte value.
+     * Allocates a memory segment with the given layout and initializes it with the given byte value.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
      * @param value the value to be set on the newly allocated memory block.
@@ -100,7 +98,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given char value.
+     * Allocates a memory segment with the given layout and initializes it with the given char value.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
      * @param value the value to be set on the newly allocated memory block.
@@ -115,7 +113,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given short value.
+     * Allocates a memory segment with the given layout and initializes it with the given short value.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
      * @param value the value to be set on the newly allocated memory block.
@@ -130,7 +128,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given int value.
+     * Allocates a memory segment with the given layout and initializes it with the given int value.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
      * @param value the value to be set on the newly allocated memory block.
@@ -145,7 +143,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given float value.
+     * Allocates a memory segment with the given layout and initializes it with the given float value.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
      * @param value the value to be set on the newly allocated memory block.
@@ -160,7 +158,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given long value.
+     * Allocates a memory segment with the given layout and initializes it with the given long value.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
      * @param value the value to be set on the newly allocated memory block.
@@ -175,7 +173,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given double value.
+     * Allocates a memory segment with the given layout and initializes it with the given double value.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
      * @param value the value to be set on the newly allocated memory block.
@@ -190,8 +188,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given address value
+     * Allocates a memory segment with the given layout and initializes it with the given address value.
-     * (expressed as an {@link Addressable} instance).
      * The address value might be narrowed according to the platform address size (see {@link ValueLayout#ADDRESS}).
      * @implSpec the default implementation for this method calls {@code this.allocate(layout)}.
      * @param layout the layout of the block of memory to be allocated.
@@ -207,80 +204,80 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given byte array.
+     * Allocates a memory segment with the given layout and initializes it with the given byte elements.
      * @implSpec the default implementation for this method calls {@code this.allocateArray(layout, array.length)}.
      * @param elementLayout the element layout of the array to be allocated.
-     * @param array the array to be copied on the newly allocated memory block.
+     * @param elements the byte elements to be copied to the newly allocated memory block.
      * @return a segment for the newly allocated memory block.
      */
-    default MemorySegment allocateArray(ValueLayout.OfByte elementLayout, byte[] array) {
+    default MemorySegment allocateArray(ValueLayout.OfByte elementLayout, byte... elements) {
-        return copyArrayWithSwapIfNeeded(array, elementLayout, MemorySegment::ofArray);
+        return copyArrayWithSwapIfNeeded(elements, elementLayout, MemorySegment::ofArray);
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given short array.
+     * Allocates a memory segment with the given layout and initializes it with the given short elements.
      * @implSpec the default implementation for this method calls {@code this.allocateArray(layout, array.length)}.
      * @param elementLayout the element layout of the array to be allocated.
-     * @param array the array to be copied on the newly allocated memory block.
+     * @param elements the short elements to be copied to the newly allocated memory block.
      * @return a segment for the newly allocated memory block.
      */
-    default MemorySegment allocateArray(ValueLayout.OfShort elementLayout, short[] array) {
+    default MemorySegment allocateArray(ValueLayout.OfShort elementLayout, short... elements) {
-        return copyArrayWithSwapIfNeeded(array, elementLayout, MemorySegment::ofArray);
+        return copyArrayWithSwapIfNeeded(elements, elementLayout, MemorySegment::ofArray);
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given char array.
+     * Allocates a memory segment with the given layout and initializes it with the given char elements.
      * @implSpec the default implementation for this method calls {@code this.allocateArray(layout, array.length)}.
      * @param elementLayout the element layout of the array to be allocated.
-     * @param array the array to be copied on the newly allocated memory block.
+     * @param elements the char elements to be copied to the newly allocated memory block.
      * @return a segment for the newly allocated memory block.
      */
-    default MemorySegment allocateArray(ValueLayout.OfChar elementLayout, char[] array) {
+    default MemorySegment allocateArray(ValueLayout.OfChar elementLayout, char... elements) {
-        return copyArrayWithSwapIfNeeded(array, elementLayout, MemorySegment::ofArray);
+        return copyArrayWithSwapIfNeeded(elements, elementLayout, MemorySegment::ofArray);
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given int array.
+     * Allocates a memory segment with the given layout and initializes it with the given int elements.
      * @implSpec the default implementation for this method calls {@code this.allocateArray(layout, array.length)}.
      * @param elementLayout the element layout of the array to be allocated.
-     * @param array the array to be copied on the newly allocated memory block.
+     * @param elements the int elements to be copied to the newly allocated memory block.
      * @return a segment for the newly allocated memory block.
      */
-    default MemorySegment allocateArray(ValueLayout.OfInt elementLayout, int[] array) {
+    default MemorySegment allocateArray(ValueLayout.OfInt elementLayout, int... elements) {
-        return copyArrayWithSwapIfNeeded(array, elementLayout, MemorySegment::ofArray);
+        return copyArrayWithSwapIfNeeded(elements, elementLayout, MemorySegment::ofArray);
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given float array.
+     * Allocates a memory segment with the given layout and initializes it with the given float elements.
      * @implSpec the default implementation for this method calls {@code this.allocateArray(layout, array.length)}.
      * @param elementLayout the element layout of the array to be allocated.
-     * @param array the array to be copied on the newly allocated memory block.
+     * @param elements the float elements to be copied to the newly allocated memory block.
      * @return a segment for the newly allocated memory block.
      */
-    default MemorySegment allocateArray(ValueLayout.OfFloat elementLayout, float[] array) {
+    default MemorySegment allocateArray(ValueLayout.OfFloat elementLayout, float... elements) {
-        return copyArrayWithSwapIfNeeded(array, elementLayout, MemorySegment::ofArray);
+        return copyArrayWithSwapIfNeeded(elements, elementLayout, MemorySegment::ofArray);
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given long array.
+     * Allocates a memory segment with the given layout and initializes it with the given long elements.
      * @implSpec the default implementation for this method calls {@code this.allocateArray(layout, array.length)}.
      * @param elementLayout the element layout of the array to be allocated.
-     * @param array the array to be copied on the newly allocated memory block.
+     * @param elements the long elements to be copied to the newly allocated memory block.
      * @return a segment for the newly allocated memory block.
      */
-    default MemorySegment allocateArray(ValueLayout.OfLong elementLayout, long[] array) {
+    default MemorySegment allocateArray(ValueLayout.OfLong elementLayout, long... elements) {
-        return copyArrayWithSwapIfNeeded(array, elementLayout, MemorySegment::ofArray);
+        return copyArrayWithSwapIfNeeded(elements, elementLayout, MemorySegment::ofArray);
     }
 
     /**
-     * Allocate a memory segment with given layout and initialize it with given double array.
+     * Allocates a memory segment with the given layout and initializes it with the given double elements.
      * @implSpec the default implementation for this method calls {@code this.allocateArray(layout, array.length)}.
      * @param elementLayout the element layout of the array to be allocated.
-     * @param array the array to be copied on the newly allocated memory block.
+     * @param elements the double elements to be copied to the newly allocated memory block.
      * @return a segment for the newly allocated memory block.
      */
-    default MemorySegment allocateArray(ValueLayout.OfDouble elementLayout, double[] array) {
+    default MemorySegment allocateArray(ValueLayout.OfDouble elementLayout, double... elements) {
-        return copyArrayWithSwapIfNeeded(array, elementLayout, MemorySegment::ofArray);
+        return copyArrayWithSwapIfNeeded(elements, elementLayout, MemorySegment::ofArray);
     }
 
     private <Z> MemorySegment copyArrayWithSwapIfNeeded(Z array, ValueLayout elementLayout,
@@ -295,7 +292,7 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given layout.
+     * Allocates a memory segment with the given layout.
      * @implSpec the default implementation for this method calls {@code this.allocate(layout.byteSize(), layout.byteAlignment())}.
      * @param layout the layout of the block of memory to be allocated.
      * @return a segment for the newly allocated memory block.
@@ -306,11 +303,12 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given element layout and size.
+     * Allocates a memory segment with the given element layout and size.
      * @implSpec the default implementation for this method calls {@code this.allocate(MemoryLayout.sequenceLayout(count, elementLayout))}.
      * @param elementLayout the array element layout.
      * @param count the array element count.
      * @return a segment for the newly allocated memory block.
+     * @throws IllegalArgumentException if {@code count < 0}.
      */
     default MemorySegment allocateArray(MemoryLayout elementLayout, long count) {
         Objects.requireNonNull(elementLayout);
@@ -318,68 +316,74 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Allocate a memory segment with given size
+     * Allocates a memory segment with the given size.
-     * and default alignment constraints (1-byte aligned).
      * @implSpec the default implementation for this method calls {@code this.allocate(bytesSize, 1)}.
      * @param bytesSize the size (in bytes) of the block of memory to be allocated.
      * @return a segment for the newly allocated memory block.
+     * @throws IllegalArgumentException if {@code bytesSize < 0}
      */
     default MemorySegment allocate(long bytesSize) {
         return allocate(bytesSize, 1);
     }
 
     /**
-     * Allocate a memory segment with given size and alignment constraints.
+     * Allocates a memory segment with the given size and alignment constraints.
      * @param bytesSize the size (in bytes) of the block of memory to be allocated.
      * @param bytesAlignment the alignment (in bytes) of the block of memory to be allocated.
      * @return a segment for the newly allocated memory block.
+     * @throws IllegalArgumentException if {@code bytesSize < 0}, {@code alignmentBytes <= 0},
+     * or if {@code alignmentBytes} is not a power of 2.
      */
     MemorySegment allocate(long bytesSize, long bytesAlignment);
 
     /**
-     * Returns a native unbounded arena-based allocator, with predefined block size and maximum arena size,
+     * Creates an unbounded arena-based allocator used to allocate native memory segments.
-     * associated with the provided scope. Equivalent to the following code:
+     * The returned allocator features a predefined block size and maximum arena size, and the segments it allocates
+     * are associated with the provided memory session. Equivalent to the following code:
      * {@snippet lang=java :
-     * SegmentAllocator.newNativeArena(Long.MAX_VALUE, predefinedBlockSize, scope);
+     * SegmentAllocator.newNativeArena(Long.MAX_VALUE, predefinedBlockSize, session);
      * }
      *
-     * @param scope the scope associated with the segments returned by the arena-based allocator.
+     * @param session the memory session associated with the segments allocated by the arena-based allocator.
      * @return a new unbounded arena-based allocator
-     * @throws IllegalStateException if {@code scope} has been already closed, or if access occurs from a thread other
+     * @throws IllegalStateException if {@code session} is not {@linkplain MemorySession#isAlive() alive}, or if access occurs from
-     * than the thread owning {@code scope}.
+     * a thread other than the thread {@linkplain MemorySession#ownerThread() owning} {@code session}.
      */
-    static SegmentAllocator newNativeArena(ResourceScope scope) {
+    static SegmentAllocator newNativeArena(MemorySession session) {
-        return newNativeArena(Long.MAX_VALUE, ArenaAllocator.DEFAULT_BLOCK_SIZE, scope);
+        return newNativeArena(Long.MAX_VALUE, ArenaAllocator.DEFAULT_BLOCK_SIZE, session);
     }
 
     /**
-     * Returns a native unbounded arena-based allocator, with block size set to the specified arena size, associated with
+     * Creates an arena-based allocator used to allocate native memory segments.
-     * the provided scope, with given arena size. Equivalent to the following code:
+     * The returned allocator features a block size set to the specified arena size, and the native segments
+     * it allocates are associated with the provided memory session. Equivalent to the following code:
      * {@snippet lang=java :
-     * SegmentAllocator.newNativeArena(arenaSize, arenaSize, scope);
+     * SegmentAllocator.newNativeArena(arenaSize, arenaSize, session);
      * }
      *
      * @param arenaSize the size (in bytes) of the allocation arena.
-     * @param scope the scope associated with the segments returned by the arena-based allocator.
+     * @param session the memory session associated with the segments allocated by the arena-based allocator.
      * @return a new unbounded arena-based allocator
      * @throws IllegalArgumentException if {@code arenaSize <= 0}.
-     * @throws IllegalStateException if {@code scope} has been already closed, or if access occurs from a thread other
+     * @throws IllegalStateException if {@code session} is not {@linkplain MemorySession#isAlive() alive}, or if access occurs from
-     * than the thread owning {@code scope}.
+     * a thread other than the thread {@linkplain MemorySession#ownerThread() owning} {@code session}.
      */
-    static SegmentAllocator newNativeArena(long arenaSize, ResourceScope scope) {
+    static SegmentAllocator newNativeArena(long arenaSize, MemorySession session) {
-        return newNativeArena(arenaSize, arenaSize, scope);
+        return newNativeArena(arenaSize, arenaSize, session);
     }
 
     /**
-     * Returns a native arena-based allocator, associated with the provided scope, with given arena size and block size.
+     * Creates an arena-based allocator used to allocate native memory segments. The returned allocator features
+     * the given block size {@code B} and the given arena size {@code A}, and the native segments
+     * it allocates are associated with the provided memory session.
      * <p>
-     * The returned allocator {@linkplain MemorySegment#allocateNative(long, ResourceScope) allocates} a memory segment
+     * The allocator arena is first initialized by {@linkplain MemorySegment#allocateNative(long, MemorySession) allocating} a
-     * {@code S} of the specified block size and then responds to allocation requests in one of the following ways:
+     * native memory segment {@code S} of size {@code B}. The allocator then responds to allocation requests in one of the following ways:
      * <ul>
      *     <li>if the size of the allocation requests is smaller than the size of {@code S}, and {@code S} has a <em>free</em>
      *     slice {@code S'} which fits that allocation request, return that {@code S'}.
      *     <li>if the size of the allocation requests is smaller than the size of {@code S}, and {@code S} has no <em>free</em>
-     *     slices which fits that allocation request, allocate a new segment {@code S'}, which has same size as {@code S}
+     *     slices which fits that allocation request, allocate a new segment {@code S'}, with size {@code B},
      *     and set {@code S = S'}; the allocator then tries to respond to the same allocation request again.
      *     <li>if the size of the allocation requests is bigger than the size of {@code S}, allocate a new segment {@code S'},
      *     which has a sufficient size to satisfy the allocation request, and return {@code S'}.
@@ -389,31 +393,31 @@ public interface SegmentAllocator {
      * cost associated with allocating a new off-heap memory region upon each allocation request.
      * <p>
      * The returned allocator might throw an {@link OutOfMemoryError} if the total memory allocated with this allocator
-     * exceeds the arena size, or the system capacity. Furthermore, the returned allocator is not thread safe.
+     * exceeds the arena size {@code A}, or the system capacity. Furthermore, the returned allocator is not thread safe.
      * Concurrent allocation needs to be guarded with synchronization primitives.
      *
      * @param arenaSize the size (in bytes) of the allocation arena.
      * @param blockSize the block size associated with the arena-based allocator.
-     * @param scope the scope associated with the segments returned by the arena-based allocator.
+     * @param session the memory session associated with the segments returned by the arena-based allocator.
      * @return a new unbounded arena-based allocator
      * @throws IllegalArgumentException if {@code blockSize <= 0}, if {@code arenaSize <= 0} or if {@code arenaSize < blockSize}.
-     * @throws IllegalStateException if {@code scope} has been already closed, or if access occurs from a thread other
+     * @throws IllegalStateException if {@code session} is not {@linkplain MemorySession#isAlive() alive}, or if access occurs from
-     * than the thread owning {@code scope}.
+     * a thread other than the thread {@linkplain MemorySession#ownerThread() owning} {@code session}.
      */
-    static SegmentAllocator newNativeArena(long arenaSize, long blockSize, ResourceScope scope) {
+    static SegmentAllocator newNativeArena(long arenaSize, long blockSize, MemorySession session) {
-        Objects.requireNonNull(scope);
+        Objects.requireNonNull(session);
         if (blockSize <= 0) {
             throw new IllegalArgumentException("Invalid block size: " + blockSize);
         }
         if (arenaSize <= 0 || arenaSize < blockSize) {
             throw new IllegalArgumentException("Invalid arena size: " + arenaSize);
         }
-        return new ArenaAllocator(blockSize, arenaSize, scope);
+        return new ArenaAllocator(blockSize, arenaSize, session);
     }
 
     /**
-     * Returns a segment allocator which responds to allocation requests by recycling a single segment; that is,
+     * Returns a segment allocator which responds to allocation requests by recycling a single segment. Each
-     * each new allocation request will return a new slice starting at the segment offset {@code 0} (alignment
+     * new allocation request will return a new slice starting at the segment offset {@code 0} (alignment
      * constraints are ignored by this allocator), hence the name <em>prefix allocator</em>.
      * Equivalent to (but likely more efficient than) the following code:
      * {@snippet lang=java :
@@ -437,34 +441,18 @@ public interface SegmentAllocator {
     }
 
     /**
-     * Returns a native allocator, associated with the provided scope. Equivalent to (but likely more efficient than)
+     * Returns an allocator which allocates native segments in independent {@linkplain MemorySession#openImplicit() implicit memory sessions}.
-     * the following code:
-     * {@snippet lang=java :
-     * ResourceScope scope = ...
-     * SegmentAllocator nativeAllocator = (size, align) -> MemorySegment.allocateNative(size, align, scope);
-     * }
-     *
-     * @param scope the scope associated with the returned allocator.
-     * @return a native allocator, associated with the provided scope.
-     */
-    static SegmentAllocator nativeAllocator(ResourceScope scope) {
-        Objects.requireNonNull(scope);
-        return (ResourceScopeImpl)scope;
-    }
-
-    /**
-     * Returns a native allocator which allocates segments in independent {@linkplain ResourceScope#newImplicitScope() implicit scopes}.
      * Equivalent to (but likely more efficient than) the following code:
      * {@snippet lang=java :
-     * SegmentAllocator implicitAllocator = (size, align) -> MemorySegment.allocateNative(size, align, ResourceScope.newImplicitScope());
+     * SegmentAllocator implicitAllocator = (size, align) -> MemorySegment.allocateNative(size, align, MemorySession.openImplicit());
      * }
      *
-     * @return a native allocator which allocates segments in independent {@linkplain ResourceScope#newImplicitScope() implicit scopes}.
+     * @return an allocator which allocates native segments in independent {@linkplain MemorySession#openImplicit() implicit memory sessions}.
      */
     static SegmentAllocator implicitAllocator() {
         class Holder {
             static final SegmentAllocator IMPLICIT_ALLOCATOR = (size, align) ->
-                    MemorySegment.allocateNative(size, align, ResourceScope.newImplicitScope());
+                    MemorySegment.allocateNative(size, align, MemorySession.openImplicit());
         }
         return Holder.IMPLICIT_ALLOCATOR;
     }

src/java.base/share/classes/java/lang/foreign/SequenceLayout.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -23,19 +23,18 @@
  *  questions.
  *
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;
 
-import java.lang.constant.ConstantDescs;
-import java.lang.constant.DynamicConstantDesc;
 import java.util.Objects;
 import java.util.Optional;
-import java.util.OptionalLong;
+
+import jdk.internal.javac.PreviewFeature;
 
 /**
- * A sequence layout. A sequence layout is used to denote a repetition of a given layout, also called the sequence layout's <em>element layout</em>.
+ * A compound layout that denotes a repetition of a given <em>element layout</em>.
- * The repetition count, where it exists (e.g. for <em>finite</em> sequence layouts) is said to be the sequence layout's <em>element count</em>.
+ * The repetition count is said to be the sequence layout's <em>element count</em>. A finite sequence can be thought of as a
- * A finite sequence layout can be thought of as a group layout where the sequence layout's element layout is repeated a number of times
+ * group layout where the sequence layout's element layout is repeated a number of times that is equal to the sequence
- * that is equal to the sequence layout's element count. In other words this layout:
+ * layout's element count. In other words this layout:
  *
  * {@snippet lang=java :
  * MemoryLayout.sequenceLayout(3, ValueLayout.JAVA_INT.withOrder(ByteOrder.BIG_ENDIAN));
@@ -50,33 +49,23 @@ import java.util.OptionalLong;
  *     ValueLayout.JAVA_INT.withOrder(ByteOrder.BIG_ENDIAN));
  * }
  *
- * <p>
- * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
- * class; programmers should treat instances that are
- * {@linkplain #equals(Object) equal} as interchangeable and should not
- * use instances for synchronization, or unpredictable behavior may
- * occur. For example, in a future release, synchronization may fail.
- * The {@code equals} method should be used for comparisons.
- *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
- *
  * @implSpec
- * This class is immutable and thread-safe.
+ * This class is immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
+ *
+ * @since 19
  */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
 public final class SequenceLayout extends AbstractLayout implements MemoryLayout {
 
-    private final OptionalLong elemCount;
+    private final long elemCount;
     private final MemoryLayout elementLayout;
 
-    SequenceLayout(OptionalLong elemCount, MemoryLayout elementLayout) {
+    SequenceLayout(long elemCount, MemoryLayout elementLayout) {
         this(elemCount, elementLayout, elementLayout.bitAlignment(), Optional.empty());
     }
 
-    SequenceLayout(OptionalLong elemCount, MemoryLayout elementLayout, long alignment, Optional<String> name) {
+    SequenceLayout(long elemCount, MemoryLayout elementLayout, long alignment, Optional<String> name) {
-        super(elemCount.isPresent() && AbstractLayout.optSize(elementLayout).isPresent() ?
+        super(Math.multiplyExact(elemCount, elementLayout.bitSize()), alignment, name);
-                OptionalLong.of(elemCount.getAsLong() * elementLayout.bitSize()) :
-                OptionalLong.empty(), alignment, name);
         this.elemCount = elemCount;
         this.elementLayout = elementLayout;
     }
@@ -89,26 +78,27 @@ public final class SequenceLayout extends AbstractLayout implements MemoryLayout
     }
 
     /**
-     * {@return the element count of this sequence layout (if any)}
+     * {@return the element count of this sequence layout}
      */
-    public OptionalLong elementCount() {
+    public long elementCount() {
         return elemCount;
     }
 
     /**
-     * Obtains a new sequence layout with same element layout, alignment constraints and name as this sequence layout
+     * Returns a sequence layout with the same element layout, alignment constraints and name as this sequence layout,
-     * but with the new specified element count.
+     * but with the specified element count.
      * @param elementCount the new element count.
-     * @return a new sequence with given element count.
+     * @return a sequence layout with the given element count.
      * @throws IllegalArgumentException if {@code elementCount < 0}.
      */
     public SequenceLayout withElementCount(long elementCount) {
         AbstractLayout.checkSize(elementCount, true);
-        return new SequenceLayout(OptionalLong.of(elementCount), elementLayout, alignment, name());
+        return new SequenceLayout(elementCount, elementLayout, alignment, name());
     }
 
     /**
-     * Returns a new sequence layout where element layouts in the flattened projection of this
+     * Re-arrange the elements in this sequence layout into a multi-dimensional sequence layout.
+     * The resulting layout is a sequence layout where element layouts in the flattened projection of this
      * sequence layout (see {@link #flatten()}) are re-arranged into one or more nested sequence layouts
      * according to the provided element counts. This transformation preserves the layout size;
      * that is, multiplying the provided element counts must yield the same element count
@@ -132,7 +122,7 @@ public final class SequenceLayout extends AbstractLayout implements MemoryLayout
      * var reshapeSeqImplicit2 = seq.reshape(2, -1);
      * }
      * @param elementCounts an array of element counts, of which at most one can be {@code -1}.
-     * @return a new sequence layout where element layouts in the flattened projection of this
+     * @return a sequence layout where element layouts in the flattened projection of this
      * sequence layout (see {@link #flatten()}) are re-arranged into one or more nested sequence layouts.
      * @throws UnsupportedOperationException if this sequence layout does not have an element count.
      * @throws IllegalArgumentException if two or more element counts are set to {@code -1}, or if one
@@ -145,11 +135,8 @@ public final class SequenceLayout extends AbstractLayout implements MemoryLayout
         if (elementCounts.length == 0) {
             throw new IllegalArgumentException();
         }
-        if (elementCount().isEmpty()) {
-            throw new UnsupportedOperationException("Cannot reshape a sequence layout whose element count is unspecified");
-        }
         SequenceLayout flat = flatten();
-        long expectedCount = flat.elementCount().getAsLong();
+        long expectedCount = flat.elementCount();
 
         long actualCount = 1;
         int inferPosition = -1;
@@ -186,8 +173,8 @@ public final class SequenceLayout extends AbstractLayout implements MemoryLayout
     }
 
     /**
-     * Returns a new, flattened sequence layout whose element layout is the first non-sequence
+     * Returns a flattened sequence layout. The element layout of the returned sequence layout
-     * element layout found by recursively traversing the element layouts of this sequence layout.
+     * is the first non-sequence element layout found by recursively traversing the element layouts of this sequence layout.
      * This transformation preserves the layout size; nested sequence layout in this sequence layout will
      * be dropped and their element counts will be incorporated into that of the returned sequence layout.
      * For instance, given a sequence layout of the kind:
@@ -198,32 +185,25 @@ public final class SequenceLayout extends AbstractLayout implements MemoryLayout
      * {@snippet lang=java :
      * var flattenedSeq = MemoryLayout.sequenceLayout(12, ValueLayout.JAVA_INT);
      * }
-     * @return a new sequence layout with the same size as this layout (but, possibly, with different
+     * @return a sequence layout with the same size as this layout (but, possibly, with different
      * element count), whose element layout is not a sequence layout.
      * @throws UnsupportedOperationException if this sequence layout, or one of the nested sequence layouts being
      * flattened, does not have an element count.
      */
     public SequenceLayout flatten() {
-        if (elementCount().isEmpty()) {
+        long count = elementCount();
-            throw badUnboundSequenceLayout();
-        }
-        long count = elementCount().getAsLong();
         MemoryLayout elemLayout = elementLayout();
         while (elemLayout instanceof SequenceLayout elemSeq) {
-            count = count * elemSeq.elementCount().orElseThrow(this::badUnboundSequenceLayout);
+            count = count * elemSeq.elementCount();
             elemLayout = elemSeq.elementLayout();
         }
         return MemoryLayout.sequenceLayout(count, elemLayout);
     }
 
-    private UnsupportedOperationException badUnboundSequenceLayout() {
-        return new UnsupportedOperationException("Cannot flatten a sequence layout whose element count is unspecified");
-    }
-
     @Override
     public String toString() {
         return decorateLayoutString(String.format("[%s:%s]",
-                elemCount.isPresent() ? elemCount.getAsLong() : "", elementLayout));
+                elemCount, elementLayout));
     }
 
     @Override
@@ -237,7 +217,7 @@ public final class SequenceLayout extends AbstractLayout implements MemoryLayout
         if (!(other instanceof SequenceLayout s)) {
             return false;
         }
-        return elemCount.equals(s.elemCount) && elementLayout.equals(s.elementLayout);
+        return elemCount == s.elemCount && elementLayout.equals(s.elementLayout);
     }
 
     @Override
@@ -255,15 +235,6 @@ public final class SequenceLayout extends AbstractLayout implements MemoryLayout
         return alignment == elementLayout.bitAlignment();
     }
 
-    @Override
-    public Optional<DynamicConstantDesc<SequenceLayout>> describeConstable() {
-        return Optional.of(decorateLayoutConstant(elemCount.isPresent() ?
-                DynamicConstantDesc.ofNamed(ConstantDescs.BSM_INVOKE, "value",
-                        CD_SEQUENCE_LAYOUT, MH_SIZED_SEQUENCE, elemCount.getAsLong(), elementLayout.describeConstable().get()) :
-                DynamicConstantDesc.ofNamed(ConstantDescs.BSM_INVOKE, "value",
-                        CD_SEQUENCE_LAYOUT, MH_UNSIZED_SEQUENCE, elementLayout.describeConstable().get())));
-    }
-
     //hack: the declarations below are to make javadoc happy; we could have used generics in AbstractLayout
     //but that causes issues with javadoc, see JDK-8224052
 

src/java.base/share/classes/java/lang/foreign/SymbolLookup.java

@@ -0,0 +1,252 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.lang.foreign;
+
+import jdk.internal.access.JavaLangAccess;
+import jdk.internal.access.SharedSecrets;
+import jdk.internal.foreign.MemorySessionImpl;
+import jdk.internal.javac.PreviewFeature;
+import jdk.internal.loader.BuiltinClassLoader;
+import jdk.internal.loader.NativeLibrary;
+import jdk.internal.loader.RawNativeLibraries;
+import jdk.internal.reflect.CallerSensitive;
+import jdk.internal.reflect.Reflection;
+
+import java.lang.invoke.MethodHandles;
+import java.nio.file.Path;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.BiFunction;
+
+/**
+ * A <em>symbol lookup</em> is an object that may be used to retrieve the address of a symbol in one or more libraries.
+ * A symbol is a named entity, such as a function or a global variable.
+ * <p>
+ * A symbol lookup is created with respect to a particular library (or libraries). Subsequently, the {@link SymbolLookup#lookup(String)}
+ * method takes the name of a symbol and returns the address of the symbol in that library.
+ * <p>
+ * The address of a symbol is modelled as a zero-length {@linkplain MemorySegment memory segment}. The segment can be used in different ways:
+ * <ul>
+ *     <li>It can be passed to a {@link Linker} to create a downcall method handle, which can then be used to call the foreign function at the segment's base address.</li>
+ *     <li>It can be passed to an existing {@linkplain Linker#downcallHandle(FunctionDescriptor) downcall method handle}, as an argument to the underlying foreign function.</li>
+ *     <li>It can be {@linkplain MemorySegment#set(ValueLayout.OfAddress, long, Addressable) stored} inside another memory segment.</li>
+ *     <li>It can be used to dereference memory associated with a global variable (this might require
+ *     {@link MemorySegment#ofAddress(MemoryAddress, long, MemorySession) resizing} the segment first).</li>
+ * </ul>
+ *
+ * <h2>Obtaining a symbol lookup</h2>
+ *
+ * The factory methods {@link #libraryLookup(String, MemorySession)} and {@link #libraryLookup(Path, MemorySession)}
+ * create a symbol lookup for a library known to the operating system. The library is specified by either its name or a path.
+ * The library is loaded if not already loaded. The symbol lookup, which is known as a <em>library lookup</em>, is associated
+ * with a {@linkplain  MemorySession memory session}; when the session is {@linkplain MemorySession#close() closed}, the library is unloaded:
+ *
+ * {@snippet lang=java :
+ * try (MemorySession session = MemorySession.openConfined()) {
+ *     SymbolLookup libGL = SymbolLookup.libraryLookup("libGL.so"); // libGL.so loaded here
+ *     MemorySegment glGetString = libGL.lookup("glGetString").orElseThrow();
+ *     ...
+ * } //  libGL.so unloaded here
+ * }
+ * <p>
+ * If a library was previously loaded through JNI, i.e., by {@link System#load(String)}
+ * or {@link System#loadLibrary(String)}, then the library was also associated with a particular class loader. The factory
+ * method {@link #loaderLookup()} creates a symbol lookup for all the libraries associated with the caller's class loader:
+ *
+ * {@snippet lang=java :
+ * System.loadLibrary("GL"); // libGL.so loaded here
+ * ...
+ * SymbolLookup libGL = SymbolLookup.loaderLookup();
+ * MemorySegment glGetString = libGL.lookup("glGetString").orElseThrow();
+ * }
+ *
+ * This symbol lookup, which is known as a <em>loader lookup</em>, is dynamic with respect to the libraries associated
+ * with the class loader. If other libraries are subsequently loaded through JNI and associated with the class loader,
+ * then the loader lookup will expose their symbols automatically.
+ * <p>
+ * Note that a loader lookup only exposes symbols in libraries that were previously loaded through JNI, i.e.,
+ * by {@link System#load(String)} or {@link System#loadLibrary(String)}. A loader lookup does not expose symbols in libraries
+ * that were loaded in the course of creating a library lookup:
+ *
+ * {@snippet lang=java :
+ * libraryLookup("libGL.so", session).lookup("glGetString").isPresent(); // true
+ * loaderLookup().lookup("glGetString").isPresent(); // false
+ * }
+ *
+ * Note also that a library lookup for library {@code L} exposes symbols in {@code L} even if {@code L} was previously loaded
+ * through JNI (the association with a class loader is immaterial to the library lookup):
+ *
+ * {@snippet lang=java :
+ * System.loadLibrary("GL"); // libGL.so loaded here
+ * libraryLookup("libGL.so", session).lookup("glGetString").isPresent(); // true
+ * }
+ *
+ * <p>
+ * Finally, each {@link Linker} provides a symbol lookup for libraries that are commonly used on the OS and processor
+ * combination supported by that {@link Linker}. This symbol lookup, which is known as a <em>default lookup</em>,
+ * helps clients to quickly find addresses of well-known symbols. For example, a {@link Linker} for Linux/x64 might choose to
+ * expose symbols in {@code libc} through the default lookup:
+ *
+ * {@snippet lang=java :
+ * Linker nativeLinker = Linker.nativeLinker();
+ * SymbolLookup stdlib = nativeLinker.defaultLookup();
+ * MemorySegment malloc = stdlib.lookup("malloc").orElseThrow();
+ * }
+ */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+@FunctionalInterface
+public interface SymbolLookup {
+
+    /**
+     * Returns the address of the symbol with the given name.
+     * @param name the symbol name.
+     * @return a zero-length memory segment whose base address indicates the address of the symbol, if found.
+     */
+    Optional<MemorySegment> lookup(String name);
+
+    /**
+     * Returns a symbol lookup for symbols in the libraries associated with the caller's class loader.
+     * <p>
+     * A library is associated with a class loader {@code CL} when the library is loaded via an invocation of
+     * {@link System#load(String)} or {@link System#loadLibrary(String)} from code in a class defined by {@code CL}.
+     * If that code makes further invocations of {@link System#load(String)} or {@link System#loadLibrary(String)},
+     * then more libraries are loaded and associated with {@code CL}. The symbol lookup returned by this method is always
+     * current: it reflects all the libraries associated with the relevant class loader, even if they were loaded after
+     * this method returned.
+     * <p>
+     * Libraries associated with a class loader are unloaded when the class loader becomes
+     * <a href="../../../java/lang/ref/package.html#reachability">unreachable</a>. The symbol lookup
+     * returned by this method is backed by a {@linkplain MemorySession#asNonCloseable() non-closeable}, shared memory
+     * session which keeps the caller's class loader reachable. Therefore, libraries associated with the caller's class
+     * loader are kept loaded (and their symbols available) as long as a loader lookup for that class loader is reachable.
+     * <p>
+     * In cases where this method is called from a context where there is no caller frame on the stack
+     * (e.g. when called directly from a JNI attached thread), the caller's class loader defaults to the
+     * {@linkplain ClassLoader#getSystemClassLoader system class loader}.
+     *
+     * @return a symbol lookup for symbols in the libraries associated with the caller's class loader.
+     * @see System#load(String)
+     * @see System#loadLibrary(String)
+     */
+    @CallerSensitive
+    static SymbolLookup loaderLookup() {
+        Class<?> caller = Reflection.getCallerClass();
+        // If there's no caller class, fallback to system loader
+        ClassLoader loader = caller != null ?
+                caller.getClassLoader() :
+                ClassLoader.getSystemClassLoader();
+        MemorySession loaderSession = (loader == null || loader instanceof BuiltinClassLoader) ?
+                MemorySession.global() : // builtin loaders never go away
+                MemorySessionImpl.heapSession(loader);
+        return name -> {
+            Objects.requireNonNull(name);
+            JavaLangAccess javaLangAccess = SharedSecrets.getJavaLangAccess();
+            // note: ClassLoader::findNative supports a null loader
+            MemoryAddress addr = MemoryAddress.ofLong(javaLangAccess.findNative(loader, name));
+            return addr == MemoryAddress.NULL ?
+                    Optional.empty() :
+                    Optional.of(MemorySegment.ofAddress(addr, 0L, loaderSession));
+        };
+    }
+
+    /**
+     * Loads a library with the given name (if not already loaded) and creates a symbol lookup for symbols in that library.
+     * The library will be unloaded when the provided memory session is {@linkplain MemorySession#close() closed},
+     * if no other library lookup is still using it.
+     * @implNote The process of resolving a library name is OS-specific. For instance, in a POSIX-compliant OS,
+     * the library name is resolved according to the specification of the {@code dlopen} function for that OS.
+     * In Windows, the library name is resolved according to the specification of the {@code LoadLibrary} function.
+     * <p>
+     * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
+     * Restricted methods are unsafe, and, if used incorrectly, their use might crash
+     * the JVM or, worse, silently result in memory corruption. Thus, clients should refrain from depending on
+     * restricted methods, and use safe and supported functionalities, where possible.
+     *
+     * @param name the name of the library in which symbols should be looked up.
+     * @param session the memory session which controls the library lifecycle.
+     * @return a new symbol lookup suitable to find symbols in a library with the given name.
+     * @throws IllegalArgumentException if {@code name} does not identify a valid library.
+     * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
+     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
+     */
+    @CallerSensitive
+    static SymbolLookup libraryLookup(String name, MemorySession session) {
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), SymbolLookup.class, "libraryLookup");
+        return libraryLookup(name, RawNativeLibraries::load, session);
+    }
+
+    /**
+     * Loads a library from the given path (if not already loaded) and creates a symbol lookup for symbols
+     * in that library. The library will be unloaded when the provided memory session is {@linkplain MemorySession#close() closed},
+     * if no other library lookup is still using it.
+     * <p>
+     * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
+     * Restricted methods are unsafe, and, if used incorrectly, their use might crash
+     * the JVM or, worse, silently result in memory corruption. Thus, clients should refrain from depending on
+     * restricted methods, and use safe and supported functionalities, where possible.
+     *
+     * @implNote On Linux, the functionalities provided by this factory method and the returned symbol lookup are
+     * implemented using the {@code dlopen}, {@code dlsym} and {@code dlclose} functions.
+     * @param path the path of the library in which symbols should be looked up.
+     * @param session the memory session which controls the library lifecycle.
+     * @return a new symbol lookup suitable to find symbols in a library with the given path.
+     * @throws IllegalArgumentException if {@code path} does not point to a valid library.
+     * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
+     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
+     */
+    @CallerSensitive
+    static SymbolLookup libraryLookup(Path path, MemorySession session) {
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), SymbolLookup.class, "libraryLookup");
+        return libraryLookup(path, RawNativeLibraries::load, session);
+    }
+
+    private static <Z> SymbolLookup libraryLookup(Z libDesc, BiFunction<RawNativeLibraries, Z, NativeLibrary> loadLibraryFunc, MemorySession session) {
+        Objects.requireNonNull(libDesc);
+        Objects.requireNonNull(session);
+        // attempt to load native library from path or name
+        RawNativeLibraries nativeLibraries = RawNativeLibraries.newInstance(MethodHandles.lookup());
+        NativeLibrary library = loadLibraryFunc.apply(nativeLibraries, libDesc);
+        if (library == null) {
+            throw new IllegalArgumentException("Cannot open library: " + libDesc);
+        }
+        // register hook to unload library when session is closed
+        MemorySessionImpl.toSessionImpl(session).addOrCleanupIfFail(new MemorySessionImpl.ResourceList.ResourceCleanup() {
+            @Override
+            public void cleanup() {
+                nativeLibraries.unload(library);
+            }
+        });
+        return name -> {
+            Objects.requireNonNull(name);
+            MemoryAddress addr = MemoryAddress.ofLong(library.find(name));
+            return addr == MemoryAddress.NULL
+                    ? Optional.empty() :
+                    Optional.of(MemorySegment.ofAddress(addr, 0L, session));
+        };
+    }
+}

src/java.base/share/classes/java/lang/foreign/VaList.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -23,49 +23,55 @@
  *  questions.
  *
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;
+
+import java.util.Objects;
+import java.util.function.Consumer;
 
 import jdk.internal.foreign.abi.SharedUtils;
 import jdk.internal.foreign.abi.aarch64.linux.LinuxAArch64VaList;
 import jdk.internal.foreign.abi.aarch64.macos.MacOsAArch64VaList;
 import jdk.internal.foreign.abi.x64.sysv.SysVVaList;
 import jdk.internal.foreign.abi.x64.windows.WinVaList;
+import jdk.internal.javac.PreviewFeature;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
 
-import java.util.Objects;
-import java.util.function.Consumer;
-
 /**
- * An interface that models a variable argument list, similar in functionality to a C {@code va_list}.
+ * A variable argument list, similar in functionality to a C {@code va_list}.
  * <p>
  * A variable argument list is a stateful cursor used to iterate over a set of arguments. A variable argument list
- * can be passed by reference e.g. to a {@linkplain CLinker#downcallHandle(FunctionDescriptor) downcall method handle}.
+ * can be passed by reference e.g. to a {@linkplain Linker#downcallHandle(FunctionDescriptor) downcall method handle}.
  * <p>
- * Per the C specification (see C standard 6.5.2.2 Function calls - item 6),
+ * Per the C specification (see C99 standard 6.5.2.2 Function calls - item 6),
  * arguments to variadic calls are erased by way of 'default argument promotions',
- * which erases integral types by way of integer promotion (see C standard 6.3.1.1 - item 2),
+ * which erases integral types by way of integer promotion (see C99 standard 6.3.1.1 - item 2),
  * and which erases all {@code float} arguments to {@code double}.
  * <p>
  * As such, this interface only supports reading {@code int}, {@code double},
  * and any other type that fits into a {@code long}.
  *
  * This class is not thread safe, and all accesses should occur within a single thread
- * (regardless of the scope associated with the variable arity list).
+ * (regardless of the memory session associated with the variable arity list).
  *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
+ * @since 19
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
  */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
 sealed public interface VaList extends Addressable permits WinVaList, SysVVaList, LinuxAArch64VaList, MacOsAArch64VaList, SharedUtils.EmptyVaList {
 
+    /**
+     * {@return the memory session associated with this variable argument list}
+     */
+    MemorySession session();
+
     /**
      * Reads the next value as an {@code int} and advances this variable argument list's position. The behavior of this
      * method is equivalent to the C {@code va_arg} function.
      *
      * @param layout the layout of the value to be read.
      * @return the {@code int} value read from this variable argument list.
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     int nextVarg(ValueLayout.OfInt layout);
 
@@ -75,8 +81,8 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
      *
      * @param layout the layout of the value to be read.
      * @return the {@code long} value read from this variable argument list.
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     long nextVarg(ValueLayout.OfLong layout);
 
@@ -86,8 +92,8 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
      *
      * @param layout the layout of the value
      * @return the {@code double} value read from this variable argument list.
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     double nextVarg(ValueLayout.OfDouble layout);
 
@@ -97,8 +103,8 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
      *
      * @param layout the layout of the value to be read.
      * @return the {@code MemoryAddress} value read from this variable argument list.
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     MemoryAddress nextVarg(ValueLayout.OfAddress layout);
 
@@ -117,8 +123,8 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
      * @param allocator the allocator to be used to create a segment where the contents of the variable argument list
      *                  will be copied.
      * @return the {@code MemorySegment} value read from this variable argument list.
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     MemorySegment nextVarg(GroupLayout layout, SegmentAllocator allocator);
 
@@ -126,19 +132,14 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
      * Skips a number of elements with the given memory layouts, and advances this variable argument list's position.
      *
      * @param layouts the layouts of the values to be skipped.
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     void skip(MemoryLayout... layouts);
 
-    /**
-     * {@return the resource scope associated with this variable argument list}
-     */
-    ResourceScope scope();
-
     /**
      * Copies this variable argument list at its current position into a new variable argument list associated
-     * with the same scope as this variable argument list. The behavior of this method is equivalent to the C
+     * with the same memory session as this variable argument list. The behavior of this method is equivalent to the C
      * {@code va_copy} function.
      * <p>
      * Copying is useful to traverse the variable argument list elements, starting from the current position,
@@ -146,22 +147,22 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
      * traversed multiple times.
      *
      * @return a copy of this variable argument list.
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     VaList copy();
 
     /**
      * {@return the {@linkplain MemoryAddress memory address} associated with this variable argument list}
-     * @throws IllegalStateException if the scope associated with this variable argument list has been closed, or if access occurs from
+     * @throws IllegalStateException if the {@linkplain #session() session} associated with this variable argument list is not
-     * a thread other than the thread owning that scope.
+     * {@linkplain MemorySession#isAlive() alive}, or if access occurs from a thread other than the thread owning that session.
      */
     @Override
     MemoryAddress address();
 
     /**
-     * Constructs a new variable argument list from a memory address pointing to an existing variable argument list,
+     * Creates a variable argument list from a memory address pointing to an existing variable argument list,
-     * with given resource scope.
+     * with the given memory session.
      * <p>
      * This method is <a href="package-summary.html#restricted"><em>restricted</em></a>.
      * Restricted methods are unsafe, and, if used incorrectly, their use might crash
@@ -169,60 +170,64 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
      * restricted methods, and use safe and supported functionalities, where possible.
      *
      * @param address a memory address pointing to an existing variable argument list.
-     * @param scope the resource scope to be associated with the returned variable argument list.
+     * @param session the memory session to be associated with the returned variable argument list.
      * @return a new variable argument list backed by the memory region at {@code address}.
-     * @throws IllegalStateException if {@code scope} has been already closed, or if access occurs from a thread other
+     * @throws IllegalStateException if {@code session} is not {@linkplain MemorySession#isAlive() alive}, or if access occurs from
-     * than the thread owning {@code scope}.
+     * a thread other than the thread {@linkplain MemorySession#ownerThread() owning} {@code session}.
+     * @throws UnsupportedOperationException if the underlying native platform is not supported.
      * @throws IllegalCallerException if access to this method occurs from a module {@code M} and the command line option
-     * {@code --enable-native-access} is either absent, or does not mention the module name {@code M}, or
+     * {@code --enable-native-access} is specified, but does not mention the module name {@code M}, or
      * {@code ALL-UNNAMED} in case {@code M} is an unnamed module.
      */
     @CallerSensitive
-    static VaList ofAddress(MemoryAddress address, ResourceScope scope) {
+    static VaList ofAddress(MemoryAddress address, MemorySession session) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), VaList.class, "ofAddress");
         Objects.requireNonNull(address);
-        Objects.requireNonNull(scope);
+        Objects.requireNonNull(session);
-        return SharedUtils.newVaListOfAddress(address, scope);
+        return SharedUtils.newVaListOfAddress(address, session);
     }
 
     /**
-     * Constructs a new variable argument list using a builder (see {@link Builder}), with a given resource scope.
+     * Creates a variable argument list using a builder (see {@link Builder}), with the given
+     * memory session.
      * <p>
-     * If this method needs to allocate native memory, such memory will be managed by the given
+     * If this method needs to allocate memory, such memory will be managed by the given
-     * {@linkplain ResourceScope resource scope}, and will be released when the resource scope is {@linkplain ResourceScope#close closed}.
+     * memory session, and will be released when the memory session is {@linkplain MemorySession#close closed}.
      * <p>
      * Note that when there are no elements added to the created va list,
      * this method will return the same as {@link #empty()}.
      *
      * @param actions a consumer for a builder (see {@link Builder}) which can be used to specify the elements
      *                of the underlying variable argument list.
-     * @param scope scope the scope to be associated with the new variable arity list.
+     * @param session the memory session to be associated with the new variable arity list.
      * @return a new variable argument list.
-     * @throws IllegalStateException if {@code scope} has been already closed, or if access occurs from a thread other
+     * @throws UnsupportedOperationException if the underlying native platform is not supported.
-     * than the thread owning {@code scope}.
+     * @throws IllegalStateException if {@code session} is not {@linkplain MemorySession#isAlive() alive}, or if access occurs from
+     * a thread other than the thread {@linkplain MemorySession#ownerThread() owning} {@code session}.
      */
-    static VaList make(Consumer<Builder> actions, ResourceScope scope) {
+    static VaList make(Consumer<Builder> actions, MemorySession session) {
         Objects.requireNonNull(actions);
-        Objects.requireNonNull(scope);
+        Objects.requireNonNull(session);
-        return SharedUtils.newVaList(actions, scope);
+        return SharedUtils.newVaList(actions, session);
     }
 
     /**
-     * Returns an empty variable argument list, associated with the {@linkplain ResourceScope#globalScope() global}
+     * Returns an empty variable argument list, associated with the {@linkplain MemorySession#global() global}
-     * scope. The resulting variable argument list does not contain any argument, and throws {@link UnsupportedOperationException}
+     * memory session. The resulting variable argument list does not contain any argument, and throws {@link UnsupportedOperationException}
-     * on all operations, except for {@link #scope()}, {@link #copy()} and {@link #address()}.
+     * on all operations, except for {@link VaList#address()}, {@link VaList#copy()} and {@link VaList#session()}.
      * @return an empty variable argument list.
+     * @throws UnsupportedOperationException if the underlying native platform is not supported.
      */
     static VaList empty() {
         return SharedUtils.emptyVaList();
     }
 
     /**
-     * A builder interface used to construct a variable argument list.
+     * A builder used to construct a {@linkplain VaList variable argument list}.
      *
-     * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
+     * @since 19
-     * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     sealed interface Builder permits WinVaList.Builder, SysVVaList.Builder, LinuxAArch64VaList.Builder, MacOsAArch64VaList.Builder {
 
         /**
@@ -262,7 +267,7 @@ sealed public interface VaList extends Addressable permits WinVaList, SysVVaList
         Builder addVarg(ValueLayout.OfAddress layout, Addressable value);
 
         /**
-         * Writes a {@code MemorySegment} value, with given layout, to the variable argument list being constructed.
+         * Writes a {@code MemorySegment} value, with the given layout, to the variable argument list being constructed.
          *
          * @param layout the layout of the value to be written.
          * @param value the {@code MemorySegment} whose contents will be copied.

src/java.base/share/classes/java/lang/foreign/ValueLayout.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -23,22 +23,23 @@
  *  questions.
  *
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;
+
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+import java.nio.ByteOrder;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
 
 import jdk.internal.foreign.Utils;
+import jdk.internal.javac.PreviewFeature;
 import jdk.internal.misc.Unsafe;
 import jdk.internal.vm.annotation.ForceInline;
 import jdk.internal.vm.annotation.Stable;
 import sun.invoke.util.Wrapper;
 
-import java.lang.constant.ConstantDescs;
-import java.lang.constant.DynamicConstantDesc;
-import java.lang.invoke.VarHandle;
-import java.nio.ByteOrder;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.OptionalLong;
-
 /**
  * A value layout. A value layout is used to model the memory layout associated with values of basic data types, such as <em>integral</em> types
  * (either signed or unsigned) and <em>floating-point</em> types. Each value layout has a size, an alignment (in bits),
@@ -49,20 +50,13 @@ import java.util.OptionalLong;
  * The layout constants in this class make implicit alignment and byte-ordering assumption: all layout
  * constants in this class are byte-aligned, and their byte order is set to the {@linkplain ByteOrder#nativeOrder() platform default},
  * thus making it easy to work with other APIs, such as arrays and {@link java.nio.ByteBuffer}.
- * <p>
- * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
- * class; programmers should treat instances that are
- * {@linkplain #equals(Object) equal} as interchangeable and should not
- * use instances for synchronization, or unpredictable behavior may
- * occur. For example, in a future release, synchronization may fail.
- * The {@code equals} method should be used for comparisons.
- *
- * <p> Unless otherwise specified, passing a {@code null} argument, or an array argument containing one or more {@code null}
- * elements to a method in this class causes a {@link NullPointerException NullPointerException} to be thrown. </p>
  *
  * @implSpec
- * This class is immutable and thread-safe.
+ * This class and its subclasses are immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
+ *
+ * @since 19
  */
+@PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
 public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     private final Class<?> carrier;
@@ -75,7 +69,7 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
     }
 
     ValueLayout(Class<?> carrier, ByteOrder order, long size, long alignment, Optional<String> name) {
-        super(OptionalLong.of(size), alignment, name);
+        super(size, alignment, name);
         this.carrier = carrier;
         this.order = order;
         checkCarrierSize(carrier, size);
@@ -89,10 +83,11 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
     }
 
     /**
-     * Returns a new value layout with given byte order.
+     * Returns a value layout with the same carrier, alignment constraints and name as this value layout,
+     * but with the specified byte order.
      *
      * @param order the desired byte order.
-     * @return a new value layout with given byte order.
+     * @return a value layout with the given byte order.
      */
     public ValueLayout withOrder(ByteOrder order) {
         return new ValueLayout(carrier, Objects.requireNonNull(order), bitSize(), alignment, name());
@@ -100,9 +95,11 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     @Override
     public String toString() {
-        return decorateLayoutString(String.format("%s%d",
+        char descriptor = carrier == MemoryAddress.class ? 'A' : carrier.descriptorString().charAt(0);
-                order == ByteOrder.BIG_ENDIAN ? "B" : "b",
+        if (order == ByteOrder.LITTLE_ENDIAN) {
-                bitSize()));
+            descriptor = Character.toLowerCase(descriptor);
+        }
+        return decorateLayoutString(String.format("%s%d", descriptor, bitSize()));
     }
 
     @Override
@@ -122,6 +119,62 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
             alignment == v.alignment;
     }
 
+    /**
+     * Creates a <em>strided</em> access var handle that can be used to dereference a multi-dimensional array. The
+     * layout of this array is a sequence layout with {@code shape.length} nested sequence layouts. The element
+     * layout of the sequence layout at depth {@code shape.length} is this value layout.
+     * As a result, if {@code shape.length == 0}, the array layout will feature only one dimension.
+     * <p>
+     * The resulting var handle will feature {@code sizes.length + 1} coordinates of type {@code long}, which are
+     * used as indices into a multi-dimensional array.
+     * <p>
+     * For instance, the following method call:
+     *
+     * {@snippet lang=java :
+     * VarHandle arrayHandle = ValueLayout.JAVA_INT.arrayElementVarHandle(10, 20);
+     * }
+     *
+     * Can be used to access a multi-dimensional array whose layout is as follows:
+     *
+     * {@snippet lang=java :
+     * MemoryLayout arrayLayout = MemoryLayout.sequenceLayout(-1,
+     *                                      MemoryLayout.sequenceLayout(10,
+     *                                                  MemoryLayout.sequenceLayout(20, ValueLayout.JAVA_INT)));
+     * }
+     *
+     * The resulting var handle {@code arrayHandle} will feature 3 coordinates of type {@code long}; each coordinate
+     * is interpreted as an index into the corresponding sequence layout. If we refer to the var handle coordinates, from left
+     * to right, as {@code x}, {@code y} and {@code z} respectively, the final offset dereferenced by the var handle can be
+     * computed with the following formula:
+     *
+     * <blockquote><pre>{@code
+     * offset = (10 * 20 * 4 * x) + (20 * 4 * y) + (4 * z)
+     * }</pre></blockquote>
+     *
+     * @param shape the size of each nested array dimension.
+     * @return a var handle which can be used to dereference a multi-dimensional array, featuring {@code shape.length + 1}
+     * {@code long} coordinates.
+     * @throws IllegalArgumentException if {@code shape[i] < 0}, for at least one index {@code i}.
+     * @throws UnsupportedOperationException if the layout path has one or more elements with incompatible alignment constraints.
+     * @see MethodHandles#memorySegmentViewVarHandle
+     * @see MemoryLayout#varHandle(PathElement...)
+     * @see SequenceLayout
+     */
+    public VarHandle arrayElementVarHandle(int... shape) {
+        Objects.requireNonNull(shape);
+        MemoryLayout layout = this;
+        List<PathElement> path = new ArrayList<>();
+        for (int i = shape.length ; i > 0 ; i--) {
+            int size = shape[i - 1];
+            if (size < 0) throw new IllegalArgumentException("Invalid shape size: " + size);
+            layout = MemoryLayout.sequenceLayout(size, layout);
+            path.add(PathElement.sequenceElement());
+        }
+        layout = MemoryLayout.sequenceLayout(-1, layout);
+        path.add(PathElement.sequenceElement());
+        return layout.varHandle(path.toArray(new PathElement[0]));
+    }
+
     /**
      * {@return the carrier associated with this value layout}
      */
@@ -139,12 +192,6 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
         return new ValueLayout(carrier, order, bitSize(), alignment, name());
     }
 
-    @Override
-    public Optional<DynamicConstantDesc<ValueLayout>> describeConstable() {
-        return Optional.of(decorateLayoutConstant(DynamicConstantDesc.ofNamed(ConstantDescs.BSM_INVOKE, "value",
-                CD_VALUE_LAYOUT, MH_VALUE, carrier().describeConstable().get(), order == ByteOrder.BIG_ENDIAN ? BIG_ENDIAN : LITTLE_ENDIAN)));
-    }
-
     //hack: the declarations below are to make javadoc happy; we could have used generics in AbstractLayout
     //but that causes issues with javadoc, see JDK-8224052
 
@@ -198,14 +245,17 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
     VarHandle accessHandle() {
         if (handle == null) {
             // this store to stable field is safe, because return value of 'makeMemoryAccessVarHandle' has stable identity
-            handle = Utils.makeMemoryAccessVarHandle(this, false);
+            handle = Utils.makeSegmentViewVarHandle(this);
         }
         return handle;
     }
 
     /**
      * A value layout whose carrier is {@code boolean.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfBoolean extends ValueLayout {
         OfBoolean(ByteOrder order) {
             super(boolean.class, order, 8);
@@ -239,7 +289,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code byte.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfByte extends ValueLayout {
         OfByte(ByteOrder order) {
             super(byte.class, order, 8);
@@ -273,7 +326,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code char.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfChar extends ValueLayout {
         OfChar(ByteOrder order) {
             super(char.class, order, 16);
@@ -307,7 +363,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code short.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfShort extends ValueLayout {
         OfShort(ByteOrder order) {
             super(short.class, order, 16);
@@ -341,7 +400,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code int.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfInt extends ValueLayout {
         OfInt(ByteOrder order) {
             super(int.class, order, 32);
@@ -375,7 +437,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code float.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfFloat extends ValueLayout {
         OfFloat(ByteOrder order) {
             super(float.class, order, 32);
@@ -409,7 +474,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code long.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfLong extends ValueLayout {
         OfLong(ByteOrder order) {
             super(long.class, order, 64);
@@ -443,7 +511,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code double.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfDouble extends ValueLayout {
         OfDouble(ByteOrder order) {
             super(double.class, order, 64);
@@ -477,7 +548,10 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout whose carrier is {@code MemoryAddress.class}.
+     *
+     * @since 19
      */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
     public static final class OfAddress extends ValueLayout {
         OfAddress(ByteOrder order) {
             super(MemoryAddress.class, order, ADDRESS_SIZE_BITS);
@@ -511,13 +585,15 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout constant whose size is the same as that of a machine address ({@code size_t}),
-     * bit alignment set to 8, and byte order set to {@link ByteOrder#nativeOrder()}.
+     * bit alignment set to {@code sizeof(size_t) * 8}, and byte order set to {@link ByteOrder#nativeOrder()}.
      * Equivalent to the following code:
      * {@snippet lang=java :
-     * MemoryLayout.valueLayout(MemoryAddress.class, ByteOrder.nativeOrder()).withBitAlignment(8);
+     * MemoryLayout.valueLayout(MemoryAddress.class, ByteOrder.nativeOrder())
+     *             .withBitAlignment(<address size>);
      * }
      */
-    public static final OfAddress ADDRESS = new OfAddress(ByteOrder.nativeOrder()).withBitAlignment(8);
+    public static final OfAddress ADDRESS = new OfAddress(ByteOrder.nativeOrder())
+            .withBitAlignment(ValueLayout.ADDRESS_SIZE_BITS);
 
     /**
      * A value layout constant whose size is the same as that of a Java {@code byte},
@@ -541,62 +617,62 @@ public sealed class ValueLayout extends AbstractLayout implements MemoryLayout {
 
     /**
      * A value layout constant whose size is the same as that of a Java {@code char},
-     * bit alignment set to 8, and byte order set to {@link ByteOrder#nativeOrder()}.
+     * bit alignment set to 16, and byte order set to {@link ByteOrder#nativeOrder()}.
      * Equivalent to the following code:
      * {@snippet lang=java :
-     * MemoryLayout.valueLayout(char.class, ByteOrder.nativeOrder()).withBitAlignment(8);
+     * MemoryLayout.valueLayout(char.class, ByteOrder.nativeOrder()).withBitAlignment(16);
      * }
      */
-    public static final OfChar JAVA_CHAR = new OfChar(ByteOrder.nativeOrder()).withBitAlignment(8);
+    public static final OfChar JAVA_CHAR = new OfChar(ByteOrder.nativeOrder()).withBitAlignment(16);
 
     /**
      * A value layout constant whose size is the same as that of a Java {@code short},
-     * bit alignment set to 8, and byte order set to {@link ByteOrder#nativeOrder()}.
+     * bit alignment set to 16, and byte order set to {@link ByteOrder#nativeOrder()}.
      * Equivalent to the following code:
      * {@snippet lang=java :
-     * MemoryLayout.valueLayout(short.class, ByteOrder.nativeOrder()).withBitAlignment(8);
+     * MemoryLayout.valueLayout(short.class, ByteOrder.nativeOrder()).withBitAlignment(16);
      * }
      */
-    public static final OfShort JAVA_SHORT = new OfShort(ByteOrder.nativeOrder()).withBitAlignment(8);
+    public static final OfShort JAVA_SHORT = new OfShort(ByteOrder.nativeOrder()).withBitAlignment(16);
 
     /**
      * A value layout constant whose size is the same as that of a Java {@code int},
-     * bit alignment set to 8, and byte order set to {@link ByteOrder#nativeOrder()}.
+     * bit alignment set to 32, and byte order set to {@link ByteOrder#nativeOrder()}.
      * Equivalent to the following code:
      * {@snippet lang=java :
-     * MemoryLayout.valueLayout(int.class, ByteOrder.nativeOrder()).withBitAlignment(8);
+     * MemoryLayout.valueLayout(int.class, ByteOrder.nativeOrder()).withBitAlignment(32);
      * }
      */
-    public static final OfInt JAVA_INT = new OfInt(ByteOrder.nativeOrder()).withBitAlignment(8);
+    public static final OfInt JAVA_INT = new OfInt(ByteOrder.nativeOrder()).withBitAlignment(32);
 
     /**
      * A value layout constant whose size is the same as that of a Java {@code long},
-     * bit alignment set to 8, and byte order set to {@link ByteOrder#nativeOrder()}.
+     * bit alignment set to 64, and byte order set to {@link ByteOrder#nativeOrder()}.
      * Equivalent to the following code:
      * {@snippet lang=java :
-     * MemoryLayout.valueLayout(long.class, ByteOrder.nativeOrder()).withBitAlignment(8);
+     * MemoryLayout.valueLayout(long.class, ByteOrder.nativeOrder()).withBitAlignment(64);
      * }
      */
     public static final OfLong JAVA_LONG = new OfLong(ByteOrder.nativeOrder())
-            .withBitAlignment(8);
+            .withBitAlignment(64);
 
     /**
      * A value layout constant whose size is the same as that of a Java {@code float},
-     * bit alignment set to 8, and byte order set to {@link ByteOrder#nativeOrder()}.
+     * bit alignment set to 32, and byte order set to {@link ByteOrder#nativeOrder()}.
      * Equivalent to the following code:
      * {@snippet lang=java :
-     * MemoryLayout.valueLayout(float.class, ByteOrder.nativeOrder()).withBitAlignment(8);
+     * MemoryLayout.valueLayout(float.class, ByteOrder.nativeOrder()).withBitAlignment(32);
      * }
      */
-    public static final OfFloat JAVA_FLOAT = new OfFloat(ByteOrder.nativeOrder()).withBitAlignment(8);
+    public static final OfFloat JAVA_FLOAT = new OfFloat(ByteOrder.nativeOrder()).withBitAlignment(32);
 
     /**
      * A value layout constant whose size is the same as that of a Java {@code double},
-     * bit alignment set to 8, and byte order set to {@link ByteOrder#nativeOrder()}.
+     * bit alignment set to 64, and byte order set to {@link ByteOrder#nativeOrder()}.
      * Equivalent to the following code:
      * {@snippet lang=java :
-     * MemoryLayout.valueLayout(double.class, ByteOrder.nativeOrder()).withBitAlignment(8);
+     * MemoryLayout.valueLayout(double.class, ByteOrder.nativeOrder()).withBitAlignment(64);
      * }
      */
-    public static final OfDouble JAVA_DOUBLE = new OfDouble(ByteOrder.nativeOrder()).withBitAlignment(8);
+    public static final OfDouble JAVA_DOUBLE = new OfDouble(ByteOrder.nativeOrder()).withBitAlignment(64);
 }

src/java.base/share/classes/java/lang/foreign/package-info.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -25,26 +25,24 @@
  */
 
 /**
- * <p> Classes to support low-level and efficient foreign memory/function access, directly from Java.
+ * <p>Provides low-level access to memory and functions outside the Java runtime.
  *
  * <h2>Foreign memory access</h2>
  *
  * <p>
- * The main abstraction introduced to support foreign memory access is {@link jdk.incubator.foreign.MemorySegment}, which
+ * The main abstraction introduced to support foreign memory access is {@link java.lang.foreign.MemorySegment}, which
- * models a contiguous memory region, which can reside either inside or outside the Java heap.
+ * models a contiguous memory region, residing either inside or outside the Java heap. The contents of a memory
- * A memory segment represents the main access coordinate of a memory access var handle, which can be obtained
+ * segment can be described using a {@link java.lang.foreign.MemoryLayout memory layout}, which provides
- * using the combinator methods defined in the {@link jdk.incubator.foreign.MemoryHandles} class; a set of
+ * basic operations to query sizes, offsets and alignment constraints. Memory layouts also provide
- * common dereference and copy operations is provided also by the {@link jdk.incubator.foreign.MemorySegment} class, which can
+ * an alternate, more abstract way, to <a href=MemorySegment.html#segment-deref>dereference memory segments</a>
- * be useful for simple, non-structured access. Finally, the {@link jdk.incubator.foreign.MemoryLayout} class
+ * using {@linkplain java.lang.foreign.MemoryLayout#varHandle(java.lang.foreign.MemoryLayout.PathElement...) access var handles},
- * hierarchy enables description of <em>memory layouts</em> and basic operations such as computing the size in bytes of a given
+ * which can be computed using <a href="MemoryLayout.html#layout-paths"><em>layout paths</em></a>.
- * layout, obtain its alignment requirements, and so on. Memory layouts also provide an alternate, more abstract way, to produce
- * memory access var handles, e.g. using <a href="MemoryLayout.html#layout-paths"><em>layout paths</em></a>.
  *
  * For example, to allocate an off-heap memory region big enough to hold 10 values of the primitive type {@code int}, and fill it with values
  * ranging from {@code 0} to {@code 9}, we can use the following code:
  *
  * {@snippet lang=java :
- * MemorySegment segment = MemorySegment.allocateNative(10 * 4, ResourceScope.newImplicitScope());
+ * MemorySegment segment = MemorySegment.allocateNative(10 * 4, MemorySession.openImplicit());
  * for (int i = 0 ; i < 10 ; i++) {
  *     segment.setAtIndex(ValueLayout.JAVA_INT, i, i);
  * }
@@ -53,8 +51,8 @@
  * This code creates a <em>native</em> memory segment, that is, a memory segment backed by
  * off-heap memory; the size of the segment is 40 bytes, enough to store 10 values of the primitive type {@code int}.
  * Inside a loop, we then initialize the contents of the memory segment; note how the
- * {@linkplain jdk.incubator.foreign.MemorySegment#setAtIndex(ValueLayout.OfInt, long, int) dereference method}
+ * {@linkplain java.lang.foreign.MemorySegment#setAtIndex(ValueLayout.OfInt, long, int) dereference method}
- * accepts a {@linkplain jdk.incubator.foreign.ValueLayout value layout}, which specifies the size, alignment constraints,
+ * accepts a {@linkplain java.lang.foreign.ValueLayout value layout}, which specifies the size, alignment constraints,
  * byte order as well as the Java type ({@code int}, in this case) associated with the dereference operation. More specifically,
  * if we view the memory segment as a set of 10 adjacent slots, {@code s[i]}, where {@code 0 <= i < 10},
  * where the size of each slot is exactly 4 bytes, the initialization logic above will set each slot
@@ -67,18 +65,18 @@
  * and in a timely fashion. For this reason, there might be cases where waiting for the garbage collector to determine that a segment
  * is <a href="../../../java/lang/ref/package.html#reachability">unreachable</a> is not optimal.
  * Clients that operate under these assumptions might want to programmatically release the memory associated
- * with a memory segment. This can be done, using the {@link jdk.incubator.foreign.ResourceScope} abstraction, as shown below:
+ * with a memory segment. This can be done, using the {@link java.lang.foreign.MemorySession} abstraction, as shown below:
  *
  * {@snippet lang=java :
- * try (ResourceScope scope = ResourceScope.newConfinedScope()) {
+ * try (MemorySession session = MemorySession.openConfined()) {
- *     MemorySegment segment = MemorySegment.allocateNative(10 * 4, scope);
+ *     MemorySegment segment = MemorySegment.allocateNative(10 * 4, session);
  *     for (int i = 0 ; i < 10 ; i++) {
  *         segment.setAtIndex(ValueLayout.JAVA_INT, i, i);
  *     }
  * }
  * }
  *
- * This example is almost identical to the prior one; this time we first create a so called <em>resource scope</em>,
+ * This example is almost identical to the prior one; this time we first create a so called <em>memory session</em>,
  * which is used to <em>bind</em> the life-cycle of the segment created immediately afterwards. Note the use of the
  * <em>try-with-resources</em> construct: this idiom ensures that all the memory resources associated with the segment will be released
  * at the end of the block, according to the semantics described in Section {@jls 14.20.3} of <cite>The Java Language Specification</cite>.
@@ -92,82 +90,82 @@
  * Section {@jls 15.10.4} of <cite>The Java Language Specification</cite>.
  * <p>
  * Since memory segments can be closed (see above), segments are also validated (upon access) to make sure that
- * the resource scope associated with the segment being accessed has not been closed prematurely.
+ * the memory session associated with the segment being accessed has not been closed prematurely.
  * We call this guarantee <em>temporal safety</em>. Together, spatial and temporal safety ensure that each memory access
  * operation either succeeds - and accesses a valid memory location - or fails.
  *
  * <h2>Foreign function access</h2>
- * The key abstractions introduced to support foreign function access are {@link jdk.incubator.foreign.SymbolLookup},
+ * The key abstractions introduced to support foreign function access are {@link java.lang.foreign.SymbolLookup},
- * {@link jdk.incubator.foreign.MemoryAddress} and {@link jdk.incubator.foreign.CLinker}.
+ * {@link java.lang.foreign.FunctionDescriptor} and {@link java.lang.foreign.Linker}. The first is used to look up symbols
- * The first is used to look up symbols inside native libraries; the second is used to model native addresses (more on that later),
+ * inside libraries; the second is used to model the signature of foreign functions, while the third provides
- * while the third provides linking capabilities which allows modelling foreign functions as {@link java.lang.invoke.MethodHandle} instances,
+ * linking capabilities which allows modelling foreign functions as {@link java.lang.invoke.MethodHandle} instances,
- * so that clients can perform foreign function calls directly in Java, without the need for intermediate layers of native
+ * so that clients can perform foreign function calls directly in Java, without the need for intermediate layers of C/C++
  * code (as is the case with the <a href="{@docRoot}/../specs/jni/index.html">Java Native Interface (JNI)</a>).
  * <p>
  * For example, to compute the length of a string using the C standard library function {@code strlen} on a Linux x64 platform,
  * we can use the following code:
  *
  * {@snippet lang=java :
- * var linker = CLinker.systemCLinker();
+ * var linker = Linker.nativeLinker();
  * MethodHandle strlen = linker.downcallHandle(
  *     linker.lookup("strlen").get(),
  *     FunctionDescriptor.of(ValueLayout.JAVA_LONG, ValueLayout.ADDRESS)
  * );
  *
- * try (var scope = ResourceScope.newConfinedScope()) {
+ * try (var session = MemorySession.openConfined()) {
- *     var cString = MemorySegment.allocateNative(5 + 1, scope);
+ *     var cString = MemorySegment.allocateNative(5 + 1, session);
  *     cString.setUtf8String("Hello");
  *     long len = (long)strlen.invoke(cString); // 5
  * }
  * }
  *
- * Here, we obtain a {@linkplain jdk.incubator.foreign.CLinker#systemCLinker() linker instance} and we use it
+ * Here, we obtain a {@linkplain java.lang.foreign.Linker#nativeLinker() native linker} and we use it
- * to {@linkplain jdk.incubator.foreign.CLinker#lookup(java.lang.String) look up} the {@code strlen} symbol in the
+ * to {@linkplain java.lang.foreign.SymbolLookup#lookup(java.lang.String) look up} the {@code strlen} symbol in the
  * standard C library; a <em>downcall method handle</em> targeting said symbol is subsequently
- * {@linkplain jdk.incubator.foreign.CLinker#downcallHandle(jdk.incubator.foreign.FunctionDescriptor) obtained}.
+ * {@linkplain java.lang.foreign.Linker#downcallHandle(java.lang.foreign.FunctionDescriptor) obtained}.
- * To complete the linking successfully, we must provide a {@link jdk.incubator.foreign.FunctionDescriptor} instance,
+ * To complete the linking successfully, we must provide a {@link java.lang.foreign.FunctionDescriptor} instance,
  * describing the signature of the {@code strlen} function.
  * From this information, the linker will uniquely determine the sequence of steps which will turn
  * the method handle invocation (here performed using {@link java.lang.invoke.MethodHandle#invoke(java.lang.Object...)})
- * into a foreign function call, according to the rules specified by the platform C ABI.
+ * into a foreign function call, according to the rules specified by the ABI of the underlying platform.
- * The {@link jdk.incubator.foreign.MemorySegment} class also provides many useful methods for
+ * The {@link java.lang.foreign.MemorySegment} class also provides many useful methods for
- * interacting with native code, such as converting Java strings
+ * interacting with foreign code, such as converting Java strings
- * {@linkplain jdk.incubator.foreign.MemorySegment#setUtf8String(long, java.lang.String) into} native strings and
+ * {@linkplain java.lang.foreign.MemorySegment#setUtf8String(long, java.lang.String) into} zero-terminated, UTF-8 strings and
- * {@linkplain jdk.incubator.foreign.MemorySegment#getUtf8String(long) back}, as demonstrated in the above example.
+ * {@linkplain java.lang.foreign.MemorySegment#getUtf8String(long) back}, as demonstrated in the above example.
  *
  * <h3>Foreign addresses</h3>
  *
  * When a memory segment is created from Java code, the segment properties (spatial bounds, temporal bounds and confinement)
- * are fully known at segment creation. But when interacting with native libraries, clients will often receive <em>raw</em> pointers.
+ * are fully known at segment creation. But when interacting with foreign functions, clients will often receive <em>raw</em> pointers.
  * Such pointers have no spatial bounds. For example, the C type {@code char*} can refer to a single {@code char} value,
  * or an array of {@code char} values, of given size. Nor do said pointers have any notion of temporal bounds or thread-confinement.
  * <p>
- * Raw pointers are modelled using the {@link jdk.incubator.foreign.MemoryAddress} class. When clients receive a
+ * Raw pointers are modelled using the {@link java.lang.foreign.MemoryAddress} class. When clients receive a
  * memory address instance from a foreign function call, they can perform memory dereference on it directly,
  * using one of the many <em>unsafe</em>
- * {@linkplain jdk.incubator.foreign.MemoryAddress#get(jdk.incubator.foreign.ValueLayout.OfInt, long) dereference methods}
+ * {@linkplain java.lang.foreign.MemoryAddress#get(java.lang.foreign.ValueLayout.OfInt, long) dereference methods}
  * provided:
  *
  * {@snippet lang=java :
- * MemoryAddress addr = ... //obtain address from native code
+ * MemoryAddress addr = ... // obtain address from foreign function call
  * int x = addr.get(ValueLayout.JAVA_INT, 0);
  * }
  *
  * Alternatively, the client can
- * {@linkplain jdk.incubator.foreign.MemorySegment#ofAddress(jdk.incubator.foreign.MemoryAddress, long, jdk.incubator.foreign.ResourceScope) create}
+ * {@linkplain java.lang.foreign.MemorySegment#ofAddress(java.lang.foreign.MemoryAddress, long, java.lang.foreign.MemorySession) create}
  * a memory segment <em>unsafely</em>. This allows the client to inject extra knowledge about spatial bounds which might,
  * for instance, be available in the documentation of the foreign function which produced the native address.
- * Here is how an unsafe segment can be created from a native address:
+ * Here is how an unsafe segment can be created from a memory address:
  *
  * {@snippet lang=java :
- * ResourceScope scope = ... // initialize a resource scope object
+ * MemorySession session = ... // initialize a memory session object
- * MemoryAddress addr = ... //obtain address from native code
+ * MemoryAddress addr = ... // obtain address from foreign function call
- * MemorySegment segment = MemorySegment.ofAddress(addr, 4, scope); // segment is 4 bytes long
+ * MemorySegment segment = MemorySegment.ofAddress(addr, 4, session); // segment is 4 bytes long
  * int x = segment.get(ValueLayout.JAVA_INT, 0);
  * }
  *
  * <h3>Upcalls</h3>
- * The {@link jdk.incubator.foreign.CLinker} interface also allows clients to turn an existing method handle (which might point
+ * The {@link java.lang.foreign.Linker} interface also allows clients to turn an existing method handle (which might point
  * to a Java method) into a memory address, so that Java code can effectively be passed to other foreign functions.
  * For instance, we can write a method that compares two integer values, as follows:
  *
@@ -190,43 +188,51 @@
  *                                                 CLinker.upcallType(comparFunction));
  * }
  *
- * As before, we need to create a {@link jdk.incubator.foreign.FunctionDescriptor} instance, this time describing the signature
+ * As before, we need to create a {@link java.lang.foreign.FunctionDescriptor} instance, this time describing the signature
  * of the function pointer we want to create. The descriptor can be used to
- * {@linkplain jdk.incubator.foreign.CLinker#upcallType(jdk.incubator.foreign.FunctionDescriptor) derive} a method type
+ * {@linkplain java.lang.foreign.Linker#upcallType(java.lang.foreign.FunctionDescriptor) derive} a method type
  * that can be used to look up the method handle for {@code IntComparator.intCompare}.
  * <p>
  * Now that we have a method handle instance, we can turn it into a fresh function pointer,
- * using the {@link jdk.incubator.foreign.CLinker} interface, as follows:
+ * using the {@link java.lang.foreign.Linker} interface, as follows:
  *
  * {@snippet lang=java :
- * ResourceScope scope = ...
+ * MemorySession session = ...
- * Addressable comparFunc = CLinker.systemCLinker().upcallStub(
+ * Addressable comparFunc = CLinker.nativeLinker().upcallStub(
- *     intCompareHandle, intCompareDescriptor, scope);
+ *     intCompareHandle, intCompareDescriptor, session);
  * );
  * }
  *
- * The {@link jdk.incubator.foreign.FunctionDescriptor} instance created in the previous step is then used to
+ * The {@link java.lang.foreign.FunctionDescriptor} instance created in the previous step is then used to
- * {@linkplain jdk.incubator.foreign.CLinker#upcallStub(java.lang.invoke.MethodHandle, jdk.incubator.foreign.FunctionDescriptor, jdk.incubator.foreign.ResourceScope) create}
+ * {@linkplain java.lang.foreign.Linker#upcallStub(java.lang.invoke.MethodHandle, java.lang.foreign.FunctionDescriptor, java.lang.foreign.MemorySession) create}
  * a new upcall stub; the layouts in the function descriptors allow the linker to determine the sequence of steps which
- * allow foreign code to call the stub for {@code intCompareHandle} according to the rules specified by the platform C ABI.
+ * allow foreign code to call the stub for {@code intCompareHandle} according to the rules specified by the ABI of the
- * The lifecycle of the upcall stub returned by is tied to the {@linkplain jdk.incubator.foreign.ResourceScope resource scope}
+ * underlying platform.
- * provided when the upcall stub is created. This same scope is made available by the {@link jdk.incubator.foreign.NativeSymbol}
+ * The lifecycle of the upcall stub is tied to the {@linkplain java.lang.foreign.MemorySession memory session}
+ * provided when the upcall stub is created. This same session is made available by the {@link java.lang.foreign.MemorySegment}
  * instance returned by that method.
  *
  * <a id="restricted"></a>
  * <h2>Restricted methods</h2>
  * Some methods in this package are considered <em>restricted</em>. Restricted methods are typically used to bind native
  * foreign data and/or functions to first-class Java API elements which can then be used directly by clients. For instance
- * the restricted method {@link MemorySegment#ofAddress(MemoryAddress, long, ResourceScope)}
+ * the restricted method {@link java.lang.foreign.MemorySegment#ofAddress(MemoryAddress, long, MemorySession)}
- * can be used to create a fresh segment with given spatial bounds out of a native address.
+ * can be used to create a fresh segment with the given spatial bounds out of a native address.
  * <p>
  * Binding foreign data and/or functions is generally unsafe and, if done incorrectly, can result in VM crashes, or memory corruption when the bound Java API element is accessed.
- * For instance, in the case of {@link MemorySegment#ofAddress(MemoryAddress, long, ResourceScope)},
+ * For instance, in the case of {@link java.lang.foreign.MemorySegment#ofAddress(MemoryAddress, long, MemorySession)},
  * if the provided spatial bounds are incorrect, a client of the segment returned by that method might crash the VM, or corrupt
  * memory when attempting to dereference said segment. For these reasons, it is crucial for code that calls a restricted method
  * to never pass arguments that might cause incorrect binding of foreign data and/or functions to a Java API.
  * <p>
- * Access to restricted methods is <em>disabled</em> by default; to enable restricted methods, the command line option
+ * Access to restricted methods can be controlled using the command line option {@code --enable-native-access=M1,M2, ... Mn},
- * {@code --enable-native-access} must mention the name of the caller's module.
+ * where {@code M1}, {@code M2}, {@code ... Mn} are module names (for the unnamed module, the special value {@code ALL-UNNAMED}
+ * can be used). If this option is specified, access to restricted methods is only granted to the modules listed by that
+ * option. If this option is not specified, access to restricted methods is enabled for all modules, but
+ * access to restricted methods will result in runtime warnings.
+ * <p>
+ * For every class in this package, unless specified otherwise, any method arguments of reference
+ * type must not be null, and any null argument will elicit a {@code NullPointerException}.  This fact is not individually
+ * documented for methods of this API.
  */
-package jdk.incubator.foreign;
+package java.lang.foreign;

src/java.base/share/classes/java/lang/invoke/MethodHandleImpl.java

@@ -29,7 +29,6 @@ import jdk.internal.access.JavaLangInvokeAccess;
 import jdk.internal.access.SharedSecrets;
 import jdk.internal.invoke.NativeEntryPoint;
 import jdk.internal.org.objectweb.asm.ClassWriter;
-import jdk.internal.org.objectweb.asm.MethodVisitor;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
 import jdk.internal.vm.annotation.ForceInline;
@@ -1586,9 +1585,8 @@ abstract class MethodHandleImpl {
             }
 
             @Override
-            public VarHandle memoryAccessVarHandle(Class<?> carrier, boolean skipAlignmentMaskCheck, long alignmentMask,
+            public VarHandle memorySegmentViewHandle(Class<?> carrier, long alignmentMask, ByteOrder order) {
-                                                   ByteOrder order) {
+                return VarHandles.memorySegmentViewHandle(carrier, alignmentMask, order);
-                return VarHandles.makeMemoryAddressViewHandle(carrier, skipAlignmentMaskCheck, alignmentMask, order);
             }
 
             @Override

src/java.base/share/classes/java/lang/invoke/MethodHandles.java

@@ -26,6 +26,8 @@
 package java.lang.invoke;
 
 import jdk.internal.access.SharedSecrets;
+import jdk.internal.foreign.Utils;
+import jdk.internal.javac.PreviewFeature;
 import jdk.internal.misc.Unsafe;
 import jdk.internal.misc.VM;
 import jdk.internal.org.objectweb.asm.ClassReader;
@@ -42,13 +44,16 @@ import sun.reflect.misc.ReflectUtil;
 import sun.security.util.SecurityConstants;
 
 import java.lang.constant.ConstantDescs;
+import java.lang.foreign.GroupLayout;
+import java.lang.foreign.MemoryAddress;
+import java.lang.foreign.MemoryLayout;
+import java.lang.foreign.ValueLayout;
 import java.lang.invoke.LambdaForm.BasicType;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.Member;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.lang.reflect.ReflectPermission;
 import java.nio.ByteOrder;
 import java.security.ProtectionDomain;
 import java.util.ArrayList;
@@ -7863,4 +7868,299 @@ assertEquals("boojum", (String) catTrace.invokeExact("boo", "jum"));
         return expectedType;
     }
 
+    /**
+     * Creates a var handle object, which can be used to dereference a {@linkplain java.lang.foreign.MemorySegment memory segment}
+     * by viewing its contents as a sequence of the provided value layout.
+     *
+     * <p>The provided layout specifies the {@linkplain ValueLayout#carrier() carrier type},
+     * the {@linkplain ValueLayout#byteSize() byte size},
+     * the {@linkplain ValueLayout#byteAlignment() byte alignment} and the {@linkplain ValueLayout#order() byte order}
+     * associated with the returned var handle.
+     *
+     * <p>The returned var handle's type is {@code carrier} and the list of coordinate types is
+     * {@code (MemorySegment, long)}, where the {@code long} coordinate type corresponds to byte offset into
+     * a given memory segment. The returned var handle accesses bytes at an offset in a given
+     * memory segment, composing bytes to or from a value of the type {@code carrier} according to the given endianness;
+     * the alignment constraint (in bytes) for the resulting var handle is given by {@code alignmentBytes}.
+     *
+     * <p>As an example, consider the memory layout expressed by a {@link GroupLayout} instance constructed as follows:
+     * <blockquote><pre>{@code
+     *     GroupLayout seq = java.lang.foreign.MemoryLayout.structLayout(
+     *             MemoryLayout.paddingLayout(32),
+     *             ValueLayout.JAVA_INT.withOrder(ByteOrder.BIG_ENDIAN).withName("value")
+     *     );
+     * }</pre></blockquote>
+     * To access the member layout named {@code value}, we can construct a memory segment view var handle as follows:
+     * <blockquote><pre>{@code
+     *     VarHandle handle = MethodHandles.memorySegmentViewVarHandle(ValueLayout.JAVA_INT.withOrder(ByteOrder.BIG_ENDIAN)); //(MemorySegment, long) -> int
+     *     handle = MethodHandles.insertCoordinates(handle, 1, 4); //(MemorySegment) -> int
+     * }</pre></blockquote>
+     *
+     * @apiNote The resulting var handle features certain <i>access mode restrictions</i>,
+     * which are common to all memory segment view var handles. A memory segment view var handle is associated
+     * with an access size {@code S} and an alignment constraint {@code B}
+     * (both expressed in bytes). We say that a memory access operation is <em>fully aligned</em> if it occurs
+     * at a memory address {@code A} which is compatible with both alignment constraints {@code S} and {@code B}.
+     * If access is fully aligned then following access modes are supported and are
+     * guaranteed to support atomic access:
+     * <ul>
+     * <li>read write access modes for all {@code T}, with the exception of
+     *     access modes {@code get} and {@code set} for {@code long} and
+     *     {@code double} on 32-bit platforms.
+     * <li>atomic update access modes for {@code int}, {@code long},
+     *     {@code float}, {@code double} or {@link MemoryAddress}.
+     *     (Future major platform releases of the JDK may support additional
+     *     types for certain currently unsupported access modes.)
+     * <li>numeric atomic update access modes for {@code int}, {@code long} and {@link MemoryAddress}.
+     *     (Future major platform releases of the JDK may support additional
+     *     numeric types for certain currently unsupported access modes.)
+     * <li>bitwise atomic update access modes for {@code int}, {@code long} and {@link MemoryAddress}.
+     *     (Future major platform releases of the JDK may support additional
+     *     numeric types for certain currently unsupported access modes.)
+     * </ul>
+     *
+     * If {@code T} is {@code float}, {@code double} or {@link MemoryAddress} then atomic
+     * update access modes compare values using their bitwise representation
+     * (see {@link Float#floatToRawIntBits},
+     * {@link Double#doubleToRawLongBits} and {@link MemoryAddress#toRawLongValue()}, respectively).
+     * <p>
+     * Alternatively, a memory access operation is <em>partially aligned</em> if it occurs at a memory address {@code A}
+     * which is only compatible with the alignment constraint {@code B}; in such cases, access for anything other than the
+     * {@code get} and {@code set} access modes will result in an {@code IllegalStateException}. If access is partially aligned,
+     * atomic access is only guaranteed with respect to the largest power of two that divides the GCD of {@code A} and {@code S}.
+     * <p>
+     * Finally, in all other cases, we say that a memory access operation is <em>misaligned</em>; in such cases an
+     * {@code IllegalStateException} is thrown, irrespective of the access mode being used.
+     *
+     * @param layout the value layout for which a memory access handle is to be obtained.
+     * @return the new memory segment view var handle.
+     * @throws IllegalArgumentException if an illegal carrier type is used, or if {@code alignmentBytes} is not a power of two.
+     * @throws NullPointerException if {@code layout} is {@code null}.
+     * @see MemoryLayout#varHandle(MemoryLayout.PathElement...)
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public static VarHandle memorySegmentViewVarHandle(ValueLayout layout) {
+        Objects.requireNonNull(layout);
+        return Utils.makeSegmentViewVarHandle(layout);
+    }
+
+    /**
+     * Adapts a target var handle by pre-processing incoming and outgoing values using a pair of filter functions.
+     * <p>
+     * When calling e.g. {@link VarHandle#set(Object...)} on the resulting var handle, the incoming value (of type {@code T}, where
+     * {@code T} is the <em>last</em> parameter type of the first filter function) is processed using the first filter and then passed
+     * to the target var handle.
+     * Conversely, when calling e.g. {@link VarHandle#get(Object...)} on the resulting var handle, the return value obtained from
+     * the target var handle (of type {@code T}, where {@code T} is the <em>last</em> parameter type of the second filter function)
+     * is processed using the second filter and returned to the caller. More advanced access mode types, such as
+     * {@link VarHandle.AccessMode#COMPARE_AND_EXCHANGE} might apply both filters at the same time.
+     * <p>
+     * For the boxing and unboxing filters to be well-formed, their types must be of the form {@code (A... , S) -> T} and
+     * {@code (A... , T) -> S}, respectively, where {@code T} is the type of the target var handle. If this is the case,
+     * the resulting var handle will have type {@code S} and will feature the additional coordinates {@code A...} (which
+     * will be appended to the coordinates of the target var handle).
+     * <p>
+     * If the boxing and unboxing filters throw any checked exceptions when invoked, the resulting var handle will
+     * throw an {@link IllegalStateException}.
+     * <p>
+     * The resulting var handle will feature the same access modes (see {@link VarHandle.AccessMode}) and
+     * atomic access guarantees as those featured by the target var handle.
+     *
+     * @param target the target var handle
+     * @param filterToTarget a filter to convert some type {@code S} into the type of {@code target}
+     * @param filterFromTarget a filter to convert the type of {@code target} to some type {@code S}
+     * @return an adapter var handle which accepts a new type, performing the provided boxing/unboxing conversions.
+     * @throws IllegalArgumentException if {@code filterFromTarget} and {@code filterToTarget} are not well-formed, that is, they have types
+     * other than {@code (A... , S) -> T} and {@code (A... , T) -> S}, respectively, where {@code T} is the type of the target var handle,
+     * or if it's determined that either {@code filterFromTarget} or {@code filterToTarget} throws any checked exceptions.
+     * @throws NullPointerException if any of the arguments is {@code null}.
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public static VarHandle filterValue(VarHandle target, MethodHandle filterToTarget, MethodHandle filterFromTarget) {
+        return VarHandles.filterValue(target, filterToTarget, filterFromTarget);
+    }
+
+    /**
+     * Adapts a target var handle by pre-processing incoming coordinate values using unary filter functions.
+     * <p>
+     * When calling e.g. {@link VarHandle#get(Object...)} on the resulting var handle, the incoming coordinate values
+     * starting at position {@code pos} (of type {@code C1, C2 ... Cn}, where {@code C1, C2 ... Cn} are the return types
+     * of the unary filter functions) are transformed into new values (of type {@code S1, S2 ... Sn}, where {@code S1, S2 ... Sn} are the
+     * parameter types of the unary filter functions), and then passed (along with any coordinate that was left unaltered
+     * by the adaptation) to the target var handle.
+     * <p>
+     * For the coordinate filters to be well-formed, their types must be of the form {@code S1 -> T1, S2 -> T1 ... Sn -> Tn},
+     * where {@code T1, T2 ... Tn} are the coordinate types starting at position {@code pos} of the target var handle.
+     * <p>
+     * If any of the filters throws a checked exception when invoked, the resulting var handle will
+     * throw an {@link IllegalStateException}.
+     * <p>
+     * The resulting var handle will feature the same access modes (see {@link VarHandle.AccessMode}) and
+     * atomic access guarantees as those featured by the target var handle.
+     *
+     * @param target the target var handle
+     * @param pos the position of the first coordinate to be transformed
+     * @param filters the unary functions which are used to transform coordinates starting at position {@code pos}
+     * @return an adapter var handle which accepts new coordinate types, applying the provided transformation
+     * to the new coordinate values.
+     * @throws IllegalArgumentException if the handles in {@code filters} are not well-formed, that is, they have types
+     * other than {@code S1 -> T1, S2 -> T2, ... Sn -> Tn} where {@code T1, T2 ... Tn} are the coordinate types starting
+     * at position {@code pos} of the target var handle, if {@code pos} is not between 0 and the target var handle coordinate arity, inclusive,
+     * or if more filters are provided than the actual number of coordinate types available starting at {@code pos},
+     * or if it's determined that any of the filters throws any checked exceptions.
+     * @throws NullPointerException if any of the arguments is {@code null} or {@code filters} contains {@code null}.
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public static VarHandle filterCoordinates(VarHandle target, int pos, MethodHandle... filters) {
+        return VarHandles.filterCoordinates(target, pos, filters);
+    }
+
+    /**
+     * Provides a target var handle with one or more <em>bound coordinates</em>
+     * in advance of the var handle's invocation. As a consequence, the resulting var handle will feature less
+     * coordinate types than the target var handle.
+     * <p>
+     * When calling e.g. {@link VarHandle#get(Object...)} on the resulting var handle, incoming coordinate values
+     * are joined with bound coordinate values, and then passed to the target var handle.
+     * <p>
+     * For the bound coordinates to be well-formed, their types must be {@code T1, T2 ... Tn },
+     * where {@code T1, T2 ... Tn} are the coordinate types starting at position {@code pos} of the target var handle.
+     * <p>
+     * The resulting var handle will feature the same access modes (see {@link VarHandle.AccessMode}) and
+     * atomic access guarantees as those featured by the target var handle.
+     *
+     * @param target the var handle to invoke after the bound coordinates are inserted
+     * @param pos the position of the first coordinate to be inserted
+     * @param values the series of bound coordinates to insert
+     * @return an adapter var handle which inserts additional coordinates,
+     *         before calling the target var handle
+     * @throws IllegalArgumentException if {@code pos} is not between 0 and the target var handle coordinate arity, inclusive,
+     * or if more values are provided than the actual number of coordinate types available starting at {@code pos}.
+     * @throws ClassCastException if the bound coordinates in {@code values} are not well-formed, that is, they have types
+     * other than {@code T1, T2 ... Tn }, where {@code T1, T2 ... Tn} are the coordinate types starting at position {@code pos}
+     * of the target var handle.
+     * @throws NullPointerException if any of the arguments is {@code null} or {@code values} contains {@code null}.
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public static VarHandle insertCoordinates(VarHandle target, int pos, Object... values) {
+        return VarHandles.insertCoordinates(target, pos, values);
+    }
+
+    /**
+     * Provides a var handle which adapts the coordinate values of the target var handle, by re-arranging them
+     * so that the new coordinates match the provided ones.
+     * <p>
+     * The given array controls the reordering.
+     * Call {@code #I} the number of incoming coordinates (the value
+     * {@code newCoordinates.size()}), and call {@code #O} the number
+     * of outgoing coordinates (the number of coordinates associated with the target var handle).
+     * Then the length of the reordering array must be {@code #O},
+     * and each element must be a non-negative number less than {@code #I}.
+     * For every {@code N} less than {@code #O}, the {@code N}-th
+     * outgoing coordinate will be taken from the {@code I}-th incoming
+     * coordinate, where {@code I} is {@code reorder[N]}.
+     * <p>
+     * No coordinate value conversions are applied.
+     * The type of each incoming coordinate, as determined by {@code newCoordinates},
+     * must be identical to the type of the corresponding outgoing coordinate
+     * in the target var handle.
+     * <p>
+     * The reordering array need not specify an actual permutation.
+     * An incoming coordinate will be duplicated if its index appears
+     * more than once in the array, and an incoming coordinate will be dropped
+     * if its index does not appear in the array.
+     * <p>
+     * The resulting var handle will feature the same access modes (see {@link VarHandle.AccessMode}) and
+     * atomic access guarantees as those featured by the target var handle.
+     * @param target the var handle to invoke after the coordinates have been reordered
+     * @param newCoordinates the new coordinate types
+     * @param reorder an index array which controls the reordering
+     * @return an adapter var handle which re-arranges the incoming coordinate values,
+     * before calling the target var handle
+     * @throws IllegalArgumentException if the index array length is not equal to
+     * the number of coordinates of the target var handle, or if any index array element is not a valid index for
+     * a coordinate of {@code newCoordinates}, or if two corresponding coordinate types in
+     * the target var handle and in {@code newCoordinates} are not identical.
+     * @throws NullPointerException if any of the arguments is {@code null} or {@code newCoordinates} contains {@code null}.
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public static VarHandle permuteCoordinates(VarHandle target, List<Class<?>> newCoordinates, int... reorder) {
+        return VarHandles.permuteCoordinates(target, newCoordinates, reorder);
+    }
+
+    /**
+     * Adapts a target var handle by pre-processing
+     * a sub-sequence of its coordinate values with a filter (a method handle).
+     * The pre-processed coordinates are replaced by the result (if any) of the
+     * filter function and the target var handle is then called on the modified (usually shortened)
+     * coordinate list.
+     * <p>
+     * If {@code R} is the return type of the filter (which cannot be void), the target var handle must accept a value of
+     * type {@code R} as its coordinate in position {@code pos}, preceded and/or followed by
+     * any coordinate not passed to the filter.
+     * No coordinates are reordered, and the result returned from the filter
+     * replaces (in order) the whole subsequence of coordinates originally
+     * passed to the adapter.
+     * <p>
+     * The argument types (if any) of the filter
+     * replace zero or one coordinate types of the target var handle, at position {@code pos},
+     * in the resulting adapted var handle.
+     * The return type of the filter must be identical to the
+     * coordinate type of the target var handle at position {@code pos}, and that target var handle
+     * coordinate is supplied by the return value of the filter.
+     * <p>
+     * If any of the filters throws a checked exception when invoked, the resulting var handle will
+     * throw an {@link IllegalStateException}.
+     * <p>
+     * The resulting var handle will feature the same access modes (see {@link VarHandle.AccessMode}) and
+     * atomic access guarantees as those featured by the target var handle.
+     *
+     * @param target the var handle to invoke after the coordinates have been filtered
+     * @param pos the position of the coordinate to be filtered
+     * @param filter the filter method handle
+     * @return an adapter var handle which filters the incoming coordinate values,
+     * before calling the target var handle
+     * @throws IllegalArgumentException if the return type of {@code filter}
+     * is void, or it is not the same as the {@code pos} coordinate of the target var handle,
+     * if {@code pos} is not between 0 and the target var handle coordinate arity, inclusive,
+     * if the resulting var handle's type would have <a href="MethodHandle.html#maxarity">too many coordinates</a>,
+     * or if it's determined that {@code filter} throws any checked exceptions.
+     * @throws NullPointerException if any of the arguments is {@code null}.
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public static VarHandle collectCoordinates(VarHandle target, int pos, MethodHandle filter) {
+        return VarHandles.collectCoordinates(target, pos, filter);
+    }
+
+    /**
+     * Returns a var handle which will discard some dummy coordinates before delegating to the
+     * target var handle. As a consequence, the resulting var handle will feature more
+     * coordinate types than the target var handle.
+     * <p>
+     * The {@code pos} argument may range between zero and <i>N</i>, where <i>N</i> is the arity of the
+     * target var handle's coordinate types. If {@code pos} is zero, the dummy coordinates will precede
+     * the target's real arguments; if {@code pos} is <i>N</i> they will come after.
+     * <p>
+     * The resulting var handle will feature the same access modes (see {@link VarHandle.AccessMode}) and
+     * atomic access guarantees as those featured by the target var handle.
+     *
+     * @param target the var handle to invoke after the dummy coordinates are dropped
+     * @param pos position of the first coordinate to drop (zero for the leftmost)
+     * @param valueTypes the type(s) of the coordinate(s) to drop
+     * @return an adapter var handle which drops some dummy coordinates,
+     *         before calling the target var handle
+     * @throws IllegalArgumentException if {@code pos} is not between 0 and the target var handle coordinate arity, inclusive.
+     * @throws NullPointerException if any of the arguments is {@code null} or {@code valueTypes} contains {@code null}.
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public static VarHandle dropCoordinates(VarHandle target, int pos, Class<?>... valueTypes) {
+        return VarHandles.dropCoordinates(target, pos, valueTypes);
+    }
 }

src/java.base/share/classes/java/lang/invoke/VarHandle.java

@@ -472,7 +472,7 @@ import static java.lang.invoke.MethodHandleStatics.UNSAFE;
  * @since 9
  */
 public abstract sealed class VarHandle implements Constable
-     permits IndirectVarHandle, MemoryAccessVarHandleBase,
+     permits IndirectVarHandle, VarHandleSegmentViewBase,
              VarHandleByteArrayAsChars.ByteArrayViewVarHandle,
              VarHandleByteArrayAsDoubles.ByteArrayViewVarHandle,
              VarHandleByteArrayAsFloats.ByteArrayViewVarHandle,

src/java.base/share/classes/java/lang/invoke/VarHandleSegmentViewBase.java

@@ -26,17 +26,16 @@
 package java.lang.invoke;
 
 /**
- * Base class for memory access var handle implementations.
+ * Base class for memory segment var handle view implementations.
  */
-abstract sealed class MemoryAccessVarHandleBase extends VarHandle permits
+abstract sealed class VarHandleSegmentViewBase extends VarHandle permits
-        MemoryAccessVarHandleByteHelper,
+        VarHandleSegmentAsBytes,
-        MemoryAccessVarHandleCharHelper,
+        VarHandleSegmentAsChars,
-        MemoryAccessVarHandleDoubleHelper,
+        VarHandleSegmentAsDoubles,
-        MemoryAccessVarHandleFloatHelper,
+        VarHandleSegmentAsFloats,
-        MemoryAccessVarHandleIntHelper,
+        VarHandleSegmentAsInts,
-        MemoryAccessVarHandleLongHelper,
+        VarHandleSegmentAsLongs,
-        MemoryAccessVarHandleShortHelper
+        VarHandleSegmentAsShorts {
-{
 
     /** endianness **/
     final boolean be;
@@ -47,12 +46,8 @@ abstract sealed class MemoryAccessVarHandleBase extends VarHandle permits
     /** alignment constraint (in bytes, expressed as a bit mask) **/
     final long alignmentMask;
 
-    /** if true, only the base part of the address will be checked for alignment **/
+    VarHandleSegmentViewBase(VarForm form, boolean be, long length, long alignmentMask, boolean exact) {
-    final boolean skipAlignmentMaskCheck;
-
-    MemoryAccessVarHandleBase(VarForm form, boolean skipAlignmentMaskCheck, boolean be, long length, long alignmentMask, boolean exact) {
         super(form, exact);
-        this.skipAlignmentMaskCheck = skipAlignmentMaskCheck;
         this.be = be;
         this.length = length;
         this.alignmentMask = alignmentMask;

src/java.base/share/classes/java/lang/invoke/VarHandles.java

@@ -300,22 +300,17 @@ final class VarHandles {
     }
 
     /**
-     * Creates a memory access VarHandle.
+     * Creates a memory segment view var handle.
      *
-     * Resulting VarHandle will take a memory address as first argument,
+     * The resulting var handle will take a memory segment as first argument (the segment to be dereferenced),
-     * and a certain number of coordinate {@code long} parameters, depending on the length
+     * and a {@code long} as second argument (the offset into the segment).
-     * of the {@code strides} argument array.
-     *
-     * Coordinates are multiplied with corresponding scale factors ({@code strides}) and added
-     * to a single fixed offset to compute an effective offset from the given MemoryAddress for the access.
      *
      * @param carrier the Java carrier type.
-     * @param skipAlignmentMaskCheck if true, only the base part of the address will be checked for alignment.
      * @param alignmentMask alignment requirement to be checked upon access. In bytes. Expressed as a mask.
      * @param byteOrder the byte order.
      * @return the created VarHandle.
      */
-    static VarHandle makeMemoryAddressViewHandle(Class<?> carrier, boolean skipAlignmentMaskCheck, long alignmentMask,
+    static VarHandle memorySegmentViewHandle(Class<?> carrier, long alignmentMask,
                                              ByteOrder byteOrder) {
         if (!carrier.isPrimitive() || carrier == void.class || carrier == boolean.class) {
             throw new IllegalArgumentException("Invalid carrier: " + carrier.getName());
@@ -325,19 +320,19 @@ final class VarHandles {
         boolean exact = false;
 
         if (carrier == byte.class) {
-            return maybeAdapt(new MemoryAccessVarHandleByteHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
+            return maybeAdapt(new VarHandleSegmentAsBytes(be, size, alignmentMask, exact));
         } else if (carrier == char.class) {
-            return maybeAdapt(new MemoryAccessVarHandleCharHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
+            return maybeAdapt(new VarHandleSegmentAsChars(be, size, alignmentMask, exact));
         } else if (carrier == short.class) {
-            return maybeAdapt(new MemoryAccessVarHandleShortHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
+            return maybeAdapt(new VarHandleSegmentAsShorts(be, size, alignmentMask, exact));
         } else if (carrier == int.class) {
-            return maybeAdapt(new MemoryAccessVarHandleIntHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
+            return maybeAdapt(new VarHandleSegmentAsInts(be, size, alignmentMask, exact));
         } else if (carrier == float.class) {
-            return maybeAdapt(new MemoryAccessVarHandleFloatHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
+            return maybeAdapt(new VarHandleSegmentAsFloats(be, size, alignmentMask, exact));
         } else if (carrier == long.class) {
-            return maybeAdapt(new MemoryAccessVarHandleLongHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
+            return maybeAdapt(new VarHandleSegmentAsLongs(be, size, alignmentMask, exact));
         } else if (carrier == double.class) {
-            return maybeAdapt(new MemoryAccessVarHandleDoubleHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
+            return maybeAdapt(new VarHandleSegmentAsDoubles(be, size, alignmentMask, exact));
         } else {
             throw new IllegalStateException("Cannot get here");
         }

src/java.base/share/classes/java/lang/invoke/X-VarHandleByteArrayView.java.template

@@ -26,13 +26,15 @@ package java.lang.invoke;
 
 import jdk.internal.access.JavaNioAccess;
 import jdk.internal.access.SharedSecrets;
-import jdk.internal.access.foreign.MemorySegmentProxy;
+import jdk.internal.foreign.AbstractMemorySegmentImpl;
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.misc.ScopedMemoryAccess;
-import jdk.internal.misc.ScopedMemoryAccess.Scope;
 import jdk.internal.misc.Unsafe;
 import jdk.internal.util.Preconditions;
 import jdk.internal.vm.annotation.ForceInline;
 
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
 import java.nio.ByteBuffer;
 import java.nio.ReadOnlyBufferException;
 import java.util.List;
@@ -607,15 +609,15 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
 
         @ForceInline
         static int index(ByteBuffer bb, int index) {
-            MemorySegmentProxy segmentProxy = NIO_ACCESS.bufferSegment(bb);
+            MemorySegment segment = NIO_ACCESS.bufferSegment(bb);
             return Preconditions.checkIndex(index, UNSAFE.getInt(bb, BUFFER_LIMIT) - ALIGN, null);
         }
 
         @ForceInline
-        static Scope scope(ByteBuffer bb) {
+        static MemorySessionImpl session(ByteBuffer bb) {
-            MemorySegmentProxy segmentProxy = NIO_ACCESS.bufferSegment(bb);
+            MemorySegment segment = NIO_ACCESS.bufferSegment(bb);
-            return segmentProxy != null ?
+            return segment != null ?
-                    segmentProxy.scope() : null;
+                    ((AbstractMemorySegmentImpl)segment).sessionImpl() : null;
         }
 
         @ForceInline
@@ -638,13 +640,13 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
 #if[floatingPoint]
-            $rawType$ rawValue = SCOPED_MEMORY_ACCESS.get$RawType$Unaligned(scope(bb),
+            $rawType$ rawValue = SCOPED_MEMORY_ACCESS.get$RawType$Unaligned(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     ((long) index(bb, index)) + UNSAFE.getLong(bb, BUFFER_ADDRESS),
                     handle.be);
             return $Type$.$rawType$BitsTo$Type$(rawValue);
 #else[floatingPoint]
-            return SCOPED_MEMORY_ACCESS.get$Type$Unaligned(scope(bb),
+            return SCOPED_MEMORY_ACCESS.get$Type$Unaligned(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     ((long) index(bb, index)) + UNSAFE.getLong(bb, BUFFER_ADDRESS),
                     handle.be);
@@ -656,13 +658,13 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
 #if[floatingPoint]
-            SCOPED_MEMORY_ACCESS.put$RawType$Unaligned(scope(bb),
+            SCOPED_MEMORY_ACCESS.put$RawType$Unaligned(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     ((long) indexRO(bb, index)) + UNSAFE.getLong(bb, BUFFER_ADDRESS),
                     $Type$.$type$ToRaw$RawType$Bits(value),
                     handle.be);
 #else[floatingPoint]
-            SCOPED_MEMORY_ACCESS.put$Type$Unaligned(scope(bb),
+            SCOPED_MEMORY_ACCESS.put$Type$Unaligned(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     ((long) indexRO(bb, index)) + UNSAFE.getLong(bb, BUFFER_ADDRESS),
                     value,
@@ -675,7 +677,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.get$RawType$Volatile(scope(bb),
+                              SCOPED_MEMORY_ACCESS.get$RawType$Volatile(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, index(bb, index))));
         }
@@ -684,7 +686,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
         static void setVolatile(VarHandle ob, Object obb, int index, $type$ value) {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
-            SCOPED_MEMORY_ACCESS.put$RawType$Volatile(scope(bb),
+            SCOPED_MEMORY_ACCESS.put$RawType$Volatile(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, value));
@@ -695,7 +697,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.get$RawType$Acquire(scope(bb),
+                              SCOPED_MEMORY_ACCESS.get$RawType$Acquire(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, index(bb, index))));
         }
@@ -704,7 +706,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
         static void setRelease(VarHandle ob, Object obb, int index, $type$ value) {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
-            SCOPED_MEMORY_ACCESS.put$RawType$Release(scope(bb),
+            SCOPED_MEMORY_ACCESS.put$RawType$Release(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, value));
@@ -715,7 +717,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.get$RawType$Opaque(scope(bb),
+                              SCOPED_MEMORY_ACCESS.get$RawType$Opaque(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, index(bb, index))));
         }
@@ -724,7 +726,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
         static void setOpaque(VarHandle ob, Object obb, int index, $type$ value) {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
-            SCOPED_MEMORY_ACCESS.put$RawType$Opaque(scope(bb),
+            SCOPED_MEMORY_ACCESS.put$RawType$Opaque(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, value));
@@ -736,12 +738,12 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
 #if[Object]
-            return SCOPED_MEMORY_ACCESS.compareAndSetReference(scope(bb),
+            return SCOPED_MEMORY_ACCESS.compareAndSetReference(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, expected), convEndian(handle.be, value));
 #else[Object]
-            return SCOPED_MEMORY_ACCESS.compareAndSet$RawType$(scope(bb),
+            return SCOPED_MEMORY_ACCESS.compareAndSet$RawType$(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, expected), convEndian(handle.be, value));
@@ -753,7 +755,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$(scope(bb),
+                              SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, indexRO(bb, index)),
                                       convEndian(handle.be, expected), convEndian(handle.be, value)));
@@ -764,7 +766,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Acquire(scope(bb),
+                              SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Acquire(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, indexRO(bb, index)),
                                       convEndian(handle.be, expected), convEndian(handle.be, value)));
@@ -775,7 +777,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Release(scope(bb),
+                              SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Release(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, indexRO(bb, index)),
                                       convEndian(handle.be, expected), convEndian(handle.be, value)));
@@ -785,7 +787,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
         static boolean weakCompareAndSetPlain(VarHandle ob, Object obb, int index, $type$ expected, $type$ value) {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
-            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Plain(scope(bb),
+            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Plain(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, expected), convEndian(handle.be, value));
@@ -795,7 +797,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
         static boolean weakCompareAndSet(VarHandle ob, Object obb, int index, $type$ expected, $type$ value) {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
-            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(scope(bb),
+            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, expected), convEndian(handle.be, value));
@@ -805,7 +807,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
         static boolean weakCompareAndSetAcquire(VarHandle ob, Object obb, int index, $type$ expected, $type$ value) {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
-            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Acquire(scope(bb),
+            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Acquire(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, expected), convEndian(handle.be, value));
@@ -815,7 +817,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
         static boolean weakCompareAndSetRelease(VarHandle ob, Object obb, int index, $type$ expected, $type$ value) {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
-            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Release(scope(bb),
+            return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Release(session(bb),
                     UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                     address(bb, indexRO(bb, index)),
                     convEndian(handle.be, expected), convEndian(handle.be, value));
@@ -827,13 +829,13 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
 #if[Object]
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.getAndSetReference(scope(bb),
+                              SCOPED_MEMORY_ACCESS.getAndSetReference(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, indexRO(bb, index)),
                                       convEndian(handle.be, value)));
 #else[Object]
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.getAndSet$RawType$(scope(bb),
+                              SCOPED_MEMORY_ACCESS.getAndSet$RawType$(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, indexRO(bb, index)),
                                       convEndian(handle.be, value)));
@@ -845,7 +847,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.getAndSet$RawType$Acquire(scope(bb),
+                              SCOPED_MEMORY_ACCESS.getAndSet$RawType$Acquire(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, indexRO(bb, index)),
                                       convEndian(handle.be, value)));
@@ -856,7 +858,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             return convEndian(handle.be,
-                              SCOPED_MEMORY_ACCESS.getAndSet$RawType$Release(scope(bb),
+                              SCOPED_MEMORY_ACCESS.getAndSet$RawType$Release(session(bb),
                                       UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                                       address(bb, indexRO(bb, index)),
                                       convEndian(handle.be, value)));
@@ -869,7 +871,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         delta);
@@ -883,7 +885,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Acquire(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Acquire(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         delta);
@@ -897,7 +899,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Release(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Release(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         delta);
@@ -912,7 +914,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             Object base = UNSAFE.getReference(bb, BYTE_BUFFER_HB);
             long offset = address(bb, indexRO(bb, index));
             do {
-                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(scope(bb), base, offset);
+                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(session(bb), base, offset);
                 expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
             } while (!UNSAFE.weakCompareAndSet$RawType$(base, offset,
                     nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue + delta)));
@@ -926,7 +928,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -940,7 +942,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Release(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Release(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -954,7 +956,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Acquire(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Acquire(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -969,7 +971,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             Object base = UNSAFE.getReference(bb, BYTE_BUFFER_HB);
             long offset = address(bb, indexRO(bb, index));
             do {
-                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(scope(bb), base, offset);
+                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(session(bb), base, offset);
                 expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
             } while (!UNSAFE.weakCompareAndSet$RawType$(base, offset,
                     nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue | value)));
@@ -981,7 +983,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -995,7 +997,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Release(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Release(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -1009,7 +1011,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Acquire(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Acquire(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -1024,7 +1026,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             Object base = UNSAFE.getReference(bb, BYTE_BUFFER_HB);
             long offset = address(bb, indexRO(bb, index));
             do {
-                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(scope(bb), base, offset);
+                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(session(bb), base, offset);
                 expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
             } while (!UNSAFE.weakCompareAndSet$RawType$(base, offset,
                     nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue & value)));
@@ -1037,7 +1039,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -1051,7 +1053,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Release(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Release(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -1065,7 +1067,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             ByteBufferHandle handle = (ByteBufferHandle)ob;
             ByteBuffer bb = (ByteBuffer) Objects.requireNonNull(obb);
             if (handle.be == BE) {
-                return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Acquire(scope(bb),
+                return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Acquire(session(bb),
                         UNSAFE.getReference(bb, BYTE_BUFFER_HB),
                         address(bb, indexRO(bb, index)),
                         value);
@@ -1080,7 +1082,7 @@ final class VarHandleByteArrayAs$Type$s extends VarHandleByteArrayBase {
             Object base = UNSAFE.getReference(bb, BYTE_BUFFER_HB);
             long offset = address(bb, indexRO(bb, index));
             do {
-                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(scope(bb), base, offset);
+                nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(session(bb), base, offset);
                 expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
             } while (!UNSAFE.weakCompareAndSet$RawType$(base, offset,
                     nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue ^ value)));

src/java.base/share/classes/java/lang/invoke/X-VarHandleSegmentView.java.template

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -24,10 +24,11 @@
  */
 package java.lang.invoke;
 
-import jdk.internal.access.foreign.MemorySegmentProxy;
+import jdk.internal.foreign.AbstractMemorySegmentImpl;
 import jdk.internal.misc.ScopedMemoryAccess;
 import jdk.internal.vm.annotation.ForceInline;
 
+import java.lang.foreign.MemorySegment;
 import java.lang.ref.Reference;
 
 import java.util.Objects;
@@ -36,7 +37,7 @@ import static java.lang.invoke.MethodHandleStatics.UNSAFE;
 
 #warn
 
-final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase {
+final class VarHandleSegmentAs$Type$s extends VarHandleSegmentViewBase {
 
     static final boolean BE = UNSAFE.isBigEndian();
 
@@ -44,29 +45,29 @@ final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase
 
     static final int VM_ALIGN = $BoxType$.BYTES - 1;
 
-    static final VarForm FORM = new VarForm(MemoryAccessVarHandle$Type$Helper.class, MemorySegmentProxy.class, $type$.class, long.class);
+    static final VarForm FORM = new VarForm(VarHandleSegmentAs$Type$s.class, MemorySegment.class, $type$.class, long.class);
 
-    MemoryAccessVarHandle$Type$Helper(boolean skipAlignmentMaskCheck, boolean be, long length, long alignmentMask, boolean exact) {
+    VarHandleSegmentAs$Type$s(boolean be, long length, long alignmentMask, boolean exact) {
-        super(FORM, skipAlignmentMaskCheck, be, length, alignmentMask, exact);
+        super(FORM, be, length, alignmentMask, exact);
     }
 
     @Override
     final MethodType accessModeTypeUncached(VarHandle.AccessType accessType) {
-        return accessType.accessModeType(MemorySegmentProxy.class, $type$.class, long.class);
+        return accessType.accessModeType(MemorySegment.class, $type$.class, long.class);
     }
 
     @Override
-    public MemoryAccessVarHandle$Type$Helper withInvokeExactBehavior() {
+    public VarHandleSegmentAs$Type$s withInvokeExactBehavior() {
         return hasInvokeExactBehavior() ?
                 this :
-                new MemoryAccessVarHandle$Type$Helper(skipAlignmentMaskCheck, be, length, alignmentMask, true);
+                new VarHandleSegmentAs$Type$s(be, length, alignmentMask, true);
     }
 
     @Override
-    public MemoryAccessVarHandle$Type$Helper withInvokeBehavior() {
+    public VarHandleSegmentAs$Type$s withInvokeBehavior() {
         return !hasInvokeExactBehavior() ?
                 this :
-                new MemoryAccessVarHandle$Type$Helper(skipAlignmentMaskCheck, be, length, alignmentMask, false);
+                new VarHandleSegmentAs$Type$s(be, length, alignmentMask, false);
     }
 
 #if[floatingPoint]
@@ -96,58 +97,51 @@ final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase
 #end[floatingPoint]
 
     @ForceInline
-    static MemorySegmentProxy checkAddress(Object obb, long offset, long length, boolean ro) {
+    static AbstractMemorySegmentImpl checkAddress(Object obb, long offset, long length, boolean ro) {
-        MemorySegmentProxy oo = (MemorySegmentProxy)Objects.requireNonNull(obb);
+        AbstractMemorySegmentImpl oo = (AbstractMemorySegmentImpl)Objects.requireNonNull(obb);
         oo.checkAccess(offset, length, ro);
         return oo;
     }
 
     @ForceInline
-    static long offset(boolean skipAlignmentMaskCheck, MemorySegmentProxy bb, long offset, long alignmentMask) {
+    static long offset(AbstractMemorySegmentImpl bb, long offset, long alignmentMask) {
-        long address = offsetNoVMAlignCheck(skipAlignmentMaskCheck, bb, offset, alignmentMask);
+        long address = offsetNoVMAlignCheck(bb, offset, alignmentMask);
         if ((address & VM_ALIGN) != 0) {
-            throw MemoryAccessVarHandleBase.newIllegalArgumentExceptionForMisalignedAccess(address);
+            throw VarHandleSegmentViewBase.newIllegalArgumentExceptionForMisalignedAccess(address);
         }
         return address;
     }
 
     @ForceInline
-    static long offsetNoVMAlignCheck(boolean skipAlignmentMaskCheck, MemorySegmentProxy bb, long offset, long alignmentMask) {
+    static long offsetNoVMAlignCheck(AbstractMemorySegmentImpl bb, long offset, long alignmentMask) {
         long base = bb.unsafeGetOffset();
         long address = base + offset;
         long maxAlignMask = bb.maxAlignMask();
-        if (skipAlignmentMaskCheck) {
-            //note: the offset portion has already been aligned-checked, by construction
-            if (((base | maxAlignMask) & alignmentMask) != 0) {
-                throw MemoryAccessVarHandleBase.newIllegalArgumentExceptionForMisalignedAccess(address);
-            }
-        } else {
         if (((address | maxAlignMask) & alignmentMask) != 0) {
-                throw MemoryAccessVarHandleBase.newIllegalArgumentExceptionForMisalignedAccess(address);
+            throw VarHandleSegmentViewBase.newIllegalArgumentExceptionForMisalignedAccess(address);
-            }
         }
         return address;
     }
 
     @ForceInline
     static $type$ get(VarHandle ob, Object obb, long base) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, true);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, true);
 #if[floatingPoint]
-        $rawType$ rawValue = SCOPED_MEMORY_ACCESS.get$RawType$Unaligned(bb.scope(),
+        $rawType$ rawValue = SCOPED_MEMORY_ACCESS.get$RawType$Unaligned(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offsetNoVMAlignCheck(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offsetNoVMAlignCheck(bb, base, handle.alignmentMask),
                 handle.be);
         return $Type$.$rawType$BitsTo$Type$(rawValue);
 #else[floatingPoint]
 #if[byte]
-        return SCOPED_MEMORY_ACCESS.get$Type$(bb.scope(),
+        return SCOPED_MEMORY_ACCESS.get$Type$(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offsetNoVMAlignCheck(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask));
+                offsetNoVMAlignCheck(bb, base, handle.alignmentMask));
 #else[byte]
-        return SCOPED_MEMORY_ACCESS.get$Type$Unaligned(bb.scope(),
+        return SCOPED_MEMORY_ACCESS.get$Type$Unaligned(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offsetNoVMAlignCheck(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offsetNoVMAlignCheck(bb, base, handle.alignmentMask),
                 handle.be);
 #end[byte]
 #end[floatingPoint]
@@ -155,24 +149,24 @@ final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase
 
     @ForceInline
     static void set(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
 #if[floatingPoint]
-        SCOPED_MEMORY_ACCESS.put$RawType$Unaligned(bb.scope(),
+        SCOPED_MEMORY_ACCESS.put$RawType$Unaligned(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offsetNoVMAlignCheck(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offsetNoVMAlignCheck(bb, base, handle.alignmentMask),
                 $Type$.$type$ToRaw$RawType$Bits(value),
                 handle.be);
 #else[floatingPoint]
 #if[byte]
-        SCOPED_MEMORY_ACCESS.put$Type$(bb.scope(),
+        SCOPED_MEMORY_ACCESS.put$Type$(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offsetNoVMAlignCheck(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offsetNoVMAlignCheck(bb, base, handle.alignmentMask),
                 value);
 #else[byte]
-        SCOPED_MEMORY_ACCESS.put$Type$Unaligned(bb.scope(),
+        SCOPED_MEMORY_ACCESS.put$Type$Unaligned(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offsetNoVMAlignCheck(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offsetNoVMAlignCheck(bb, base, handle.alignmentMask),
                 value,
                 handle.be);
 #end[byte]
@@ -181,178 +175,178 @@ final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase
 
     @ForceInline
     static $type$ getVolatile(VarHandle ob, Object obb, long base) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, true);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, true);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask)));
+                                  offset(bb, base, handle.alignmentMask)));
     }
 
     @ForceInline
     static void setVolatile(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        SCOPED_MEMORY_ACCESS.put$RawType$Volatile(bb.scope(),
+        SCOPED_MEMORY_ACCESS.put$RawType$Volatile(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, value));
     }
 
     @ForceInline
     static $type$ getAcquire(VarHandle ob, Object obb, long base) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, true);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, true);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.get$RawType$Acquire(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.get$RawType$Acquire(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask)));
+                                  offset(bb, base, handle.alignmentMask)));
     }
 
     @ForceInline
     static void setRelease(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        SCOPED_MEMORY_ACCESS.put$RawType$Release(bb.scope(),
+        SCOPED_MEMORY_ACCESS.put$RawType$Release(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, value));
     }
 
     @ForceInline
     static $type$ getOpaque(VarHandle ob, Object obb, long base) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, true);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, true);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.get$RawType$Opaque(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.get$RawType$Opaque(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask)));
+                                  offset(bb, base, handle.alignmentMask)));
     }
 
     @ForceInline
     static void setOpaque(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        SCOPED_MEMORY_ACCESS.put$RawType$Opaque(bb.scope(),
+        SCOPED_MEMORY_ACCESS.put$RawType$Opaque(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, value));
     }
 #if[CAS]
 
     @ForceInline
     static boolean compareAndSet(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        return SCOPED_MEMORY_ACCESS.compareAndSet$RawType$(bb.scope(),
+        return SCOPED_MEMORY_ACCESS.compareAndSet$RawType$(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, expected), convEndian(handle.be, value));
     }
 
     @ForceInline
     static $type$ compareAndExchange(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                                  offset(bb, base, handle.alignmentMask),
                                   convEndian(handle.be, expected), convEndian(handle.be, value)));
     }
 
     @ForceInline
     static $type$ compareAndExchangeAcquire(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Acquire(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Acquire(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                                  offset(bb, base, handle.alignmentMask),
                                   convEndian(handle.be, expected), convEndian(handle.be, value)));
     }
 
     @ForceInline
     static $type$ compareAndExchangeRelease(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Release(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.compareAndExchange$RawType$Release(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                                  offset(bb, base, handle.alignmentMask),
                                   convEndian(handle.be, expected), convEndian(handle.be, value)));
     }
 
     @ForceInline
     static boolean weakCompareAndSetPlain(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Plain(bb.scope(),
+        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Plain(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, expected), convEndian(handle.be, value));
     }
 
     @ForceInline
     static boolean weakCompareAndSet(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.scope(),
+        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, expected), convEndian(handle.be, value));
     }
 
     @ForceInline
     static boolean weakCompareAndSetAcquire(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Acquire(bb.scope(),
+        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Acquire(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, expected), convEndian(handle.be, value));
     }
 
     @ForceInline
     static boolean weakCompareAndSetRelease(VarHandle ob, Object obb, long base, $type$ expected, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
-        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Release(bb.scope(),
+        return SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$Release(bb.sessionImpl(),
                 bb.unsafeGetBase(),
-                offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                offset(bb, base, handle.alignmentMask),
                 convEndian(handle.be, expected), convEndian(handle.be, value));
     }
 
     @ForceInline
     static $type$ getAndSet(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.getAndSet$RawType$(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.getAndSet$RawType$(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                                  offset(bb, base, handle.alignmentMask),
                                   convEndian(handle.be, value)));
     }
 
     @ForceInline
     static $type$ getAndSetAcquire(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.getAndSet$RawType$Acquire(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.getAndSet$RawType$Acquire(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                                  offset(bb, base, handle.alignmentMask),
                                   convEndian(handle.be, value)));
     }
 
     @ForceInline
     static $type$ getAndSetRelease(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         return convEndian(handle.be,
-                          SCOPED_MEMORY_ACCESS.getAndSet$RawType$Release(bb.scope(),
+                          SCOPED_MEMORY_ACCESS.getAndSet$RawType$Release(bb.sessionImpl(),
                                   bb.unsafeGetBase(),
-                                  offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                                  offset(bb, base, handle.alignmentMask),
                                   convEndian(handle.be, value)));
     }
 #end[CAS]
@@ -360,54 +354,54 @@ final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase
 
     @ForceInline
     static $type$ getAndAdd(VarHandle ob, Object obb, long base, $type$ delta) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     delta);
         } else {
-            return getAndAddConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), delta);
+            return getAndAddConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), delta);
         }
     }
 
     @ForceInline
     static $type$ getAndAddAcquire(VarHandle ob, Object obb, long base, $type$ delta) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Acquire(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Acquire(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     delta);
         } else {
-            return getAndAddConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), delta);
+            return getAndAddConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), delta);
         }
     }
 
     @ForceInline
     static $type$ getAndAddRelease(VarHandle ob, Object obb, long base, $type$ delta) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Release(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndAdd$RawType$Release(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     delta);
         } else {
-            return getAndAddConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), delta);
+            return getAndAddConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), delta);
         }
     }
 
     @ForceInline
-    static $type$ getAndAddConvEndianWithCAS(MemorySegmentProxy bb, long offset, $type$ delta) {
+    static $type$ getAndAddConvEndianWithCAS(AbstractMemorySegmentImpl  bb, long offset, $type$ delta) {
         $type$ nativeExpectedValue, expectedValue;
         Object base = bb.unsafeGetBase();
         do {
-            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.scope(),base, offset);
+            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.sessionImpl(),base, offset);
             expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
-        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.scope(),base, offset,
+        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.sessionImpl(),base, offset,
                 nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue + delta)));
         return expectedValue;
     }
@@ -416,108 +410,108 @@ final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase
 
     @ForceInline
     static $type$ getAndBitwiseOr(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseOrConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseOrConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
     static $type$ getAndBitwiseOrRelease(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Release(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Release(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseOrConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseOrConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
     static $type$ getAndBitwiseOrAcquire(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Acquire(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseOr$RawType$Acquire(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseOrConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseOrConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
-    static $type$ getAndBitwiseOrConvEndianWithCAS(MemorySegmentProxy bb, long offset, $type$ value) {
+    static $type$ getAndBitwiseOrConvEndianWithCAS(AbstractMemorySegmentImpl  bb, long offset, $type$ value) {
         $type$ nativeExpectedValue, expectedValue;
         Object base = bb.unsafeGetBase();
         do {
-            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.scope(),base, offset);
+            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.sessionImpl(),base, offset);
             expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
-        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.scope(),base, offset,
+        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.sessionImpl(),base, offset,
                 nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue | value)));
         return expectedValue;
     }
 
     @ForceInline
     static $type$ getAndBitwiseAnd(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseAndConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseAndConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
     static $type$ getAndBitwiseAndRelease(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Release(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Release(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseAndConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseAndConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
     static $type$ getAndBitwiseAndAcquire(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Acquire(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseAnd$RawType$Acquire(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseAndConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseAndConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
-    static $type$ getAndBitwiseAndConvEndianWithCAS(MemorySegmentProxy bb, long offset, $type$ value) {
+    static $type$ getAndBitwiseAndConvEndianWithCAS(AbstractMemorySegmentImpl  bb, long offset, $type$ value) {
         $type$ nativeExpectedValue, expectedValue;
         Object base = bb.unsafeGetBase();
         do {
-            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.scope(),base, offset);
+            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.sessionImpl(),base, offset);
             expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
-        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.scope(),base, offset,
+        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.sessionImpl(),base, offset,
                 nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue & value)));
         return expectedValue;
     }
@@ -525,54 +519,54 @@ final class MemoryAccessVarHandle$Type$Helper extends MemoryAccessVarHandleBase
 
     @ForceInline
     static $type$ getAndBitwiseXor(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseXorConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseXorConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
     static $type$ getAndBitwiseXorRelease(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Release(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Release(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseXorConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseXorConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
     static $type$ getAndBitwiseXorAcquire(VarHandle ob, Object obb, long base, $type$ value) {
-        MemoryAccessVarHandleBase handle = (MemoryAccessVarHandleBase)ob;
+        VarHandleSegmentViewBase handle = (VarHandleSegmentViewBase)ob;
-        MemorySegmentProxy bb = checkAddress(obb, base, handle.length, false);
+        AbstractMemorySegmentImpl bb = checkAddress(obb, base, handle.length, false);
         if (handle.be == BE) {
-            return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Acquire(bb.scope(),
+            return SCOPED_MEMORY_ACCESS.getAndBitwiseXor$RawType$Acquire(bb.sessionImpl(),
                     bb.unsafeGetBase(),
-                    offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask),
+                    offset(bb, base, handle.alignmentMask),
                     value);
         } else {
-            return getAndBitwiseXorConvEndianWithCAS(bb, offset(handle.skipAlignmentMaskCheck, bb, base, handle.alignmentMask), value);
+            return getAndBitwiseXorConvEndianWithCAS(bb, offset(bb, base, handle.alignmentMask), value);
         }
     }
 
     @ForceInline
-    static $type$ getAndBitwiseXorConvEndianWithCAS(MemorySegmentProxy bb, long offset, $type$ value) {
+    static $type$ getAndBitwiseXorConvEndianWithCAS(AbstractMemorySegmentImpl  bb, long offset, $type$ value) {
         $type$ nativeExpectedValue, expectedValue;
         Object base = bb.unsafeGetBase();
         do {
-            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.scope(),base, offset);
+            nativeExpectedValue = SCOPED_MEMORY_ACCESS.get$RawType$Volatile(bb.sessionImpl(),base, offset);
             expectedValue = $RawBoxType$.reverseBytes(nativeExpectedValue);
-        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.scope(),base, offset,
+        } while (!SCOPED_MEMORY_ACCESS.weakCompareAndSet$RawType$(bb.sessionImpl(),base, offset,
                 nativeExpectedValue, $RawBoxType$.reverseBytes(expectedValue ^ value)));
         return expectedValue;
     }

src/java.base/share/classes/java/nio/Buffer.java

@@ -27,15 +27,17 @@ package java.nio;
 
 import jdk.internal.access.JavaNioAccess;
 import jdk.internal.access.SharedSecrets;
-import jdk.internal.access.foreign.MemorySegmentProxy;
 import jdk.internal.access.foreign.UnmapperProxy;
+import jdk.internal.foreign.AbstractMemorySegmentImpl;
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.misc.ScopedMemoryAccess;
-import jdk.internal.misc.ScopedMemoryAccess.Scope;
 import jdk.internal.misc.Unsafe;
 import jdk.internal.misc.VM.BufferPool;
 import jdk.internal.vm.annotation.ForceInline;
 
 import java.io.FileDescriptor;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
 import java.util.Objects;
 import java.util.Spliterator;
 
@@ -225,12 +227,12 @@ public abstract sealed class Buffer
     long address;
 
     // Used by buffers generated by the memory access API (JEP-370)
-    final MemorySegmentProxy segment;
+    final MemorySegment segment;
 
 
     // Creates a new buffer with given address and capacity.
     //
-    Buffer(long addr, int cap, MemorySegmentProxy segment) {
+    Buffer(long addr, int cap, MemorySegment segment) {
         this.address = addr;
         this.capacity = cap;
         this.segment = segment;
@@ -239,7 +241,7 @@ public abstract sealed class Buffer
     // Creates a new buffer with the given mark, position, limit, and capacity,
     // after checking invariants.
     //
-    Buffer(int mark, int pos, int lim, int cap, MemorySegmentProxy segment) {       // package-private
+    Buffer(int mark, int pos, int lim, int cap, MemorySegment segment) {       // package-private
         if (cap < 0)
             throw createCapacityException(cap);
         this.capacity = cap;
@@ -758,20 +760,20 @@ public abstract sealed class Buffer
     }
 
     @ForceInline
-    final ScopedMemoryAccess.Scope scope() {
+    final MemorySessionImpl session() {
         if (segment != null) {
-            return segment.scope();
+            return ((AbstractMemorySegmentImpl)segment).sessionImpl();
         } else {
             return null;
         }
     }
 
-    final void checkScope() {
+    final void checkSession() {
-        ScopedMemoryAccess.Scope scope = scope();
+        MemorySessionImpl session = session();
-        if (scope != null) {
+        if (session != null) {
             try {
-                scope.checkValidState();
+                session.checkValidState();
-            } catch (ScopedMemoryAccess.Scope.ScopedAccessError e) {
+            } catch (ScopedMemoryAccess.ScopedAccessError e) {
                 throw new IllegalStateException("This segment is already closed");
             }
         }
@@ -787,17 +789,17 @@ public abstract sealed class Buffer
                 }
 
                 @Override
-                public ByteBuffer newDirectByteBuffer(long addr, int cap, Object obj, MemorySegmentProxy segment) {
+                public ByteBuffer newDirectByteBuffer(long addr, int cap, Object obj, MemorySegment segment) {
                     return new DirectByteBuffer(addr, cap, obj, segment);
                 }
 
                 @Override
-                public ByteBuffer newMappedByteBuffer(UnmapperProxy unmapperProxy, long address, int cap, Object obj, MemorySegmentProxy segment) {
+                public ByteBuffer newMappedByteBuffer(UnmapperProxy unmapperProxy, long address, int cap, Object obj, MemorySegment segment) {
                     return new DirectByteBuffer(address, cap, obj, unmapperProxy.fileDescriptor(), unmapperProxy.isSync(), segment);
                 }
 
                 @Override
-                public ByteBuffer newHeapByteBuffer(byte[] hb, int offset, int capacity, MemorySegmentProxy segment) {
+                public ByteBuffer newHeapByteBuffer(byte[] hb, int offset, int capacity, MemorySegment segment) {
                     return new HeapByteBuffer(hb, -1, 0, capacity, capacity, offset, segment);
                 }
 
@@ -821,21 +823,21 @@ public abstract sealed class Buffer
                 }
 
                 @Override
-                public MemorySegmentProxy bufferSegment(Buffer buffer) {
+                public MemorySegment bufferSegment(Buffer buffer) {
                     return buffer.segment;
                 }
 
                 @Override
-                public Runnable acquireScope(Buffer buffer, boolean async) {
+                public Runnable acquireSession(Buffer buffer, boolean async) {
-                    var scope = buffer.scope();
+                    var session = buffer.session();
-                    if (scope == null) {
+                    if (session == null) {
                         return null;
                     }
-                    if (async && scope.ownerThread() != null) {
+                    if (async && session.ownerThread() != null) {
-                        throw new IllegalStateException("Confined scope not supported");
+                        throw new IllegalStateException("Confined session not supported");
                     }
-                    scope.acquire0();
+                    session.acquire0();
-                    return scope::release0;
+                    return session::release0;
                 }
 
                 @Override

src/java.base/share/classes/java/nio/BufferMismatch.java

@@ -39,7 +39,7 @@ final class BufferMismatch {
         if (length > 7) {
             if (a.get(aOff) != b.get(bOff))
                 return 0;
-            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.scope(), b.scope(),
+            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.session(), b.session(),
                     a.base(), a.address + aOff,
                     b.base(), b.address + bOff,
                     length,
@@ -63,7 +63,7 @@ final class BufferMismatch {
             && a.charRegionOrder() != null && b.charRegionOrder() != null) {
             if (a.get(aOff) != b.get(bOff))
                 return 0;
-            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.scope(), b.scope(),
+            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.session(), b.session(),
                     a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_CHAR_INDEX_SCALE),
                     b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_CHAR_INDEX_SCALE),
                     length,
@@ -83,7 +83,7 @@ final class BufferMismatch {
         if (length > 3 && a.order() == b.order()) {
             if (a.get(aOff) != b.get(bOff))
                 return 0;
-            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.scope(), b.scope(),
+            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.session(), b.session(),
                     a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_SHORT_INDEX_SCALE),
                     b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_SHORT_INDEX_SCALE),
                     length,
@@ -103,7 +103,7 @@ final class BufferMismatch {
         if (length > 1 && a.order() == b.order()) {
             if (a.get(aOff) != b.get(bOff))
                 return 0;
-            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.scope(), b.scope(),
+            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.session(), b.session(),
                     a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_INT_INDEX_SCALE),
                     b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_INT_INDEX_SCALE),
                     length,
@@ -122,7 +122,7 @@ final class BufferMismatch {
         int i = 0;
         if (length > 1 && a.order() == b.order()) {
             if (Float.floatToRawIntBits(a.get(aOff)) == Float.floatToRawIntBits(b.get(bOff))) {
-                i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.scope(), b.scope(),
+                i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.session(), b.session(),
                         a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE),
                         b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE),
                         length,
@@ -161,7 +161,7 @@ final class BufferMismatch {
         if (length > 0 && a.order() == b.order()) {
             if (a.get(aOff) != b.get(bOff))
                 return 0;
-            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.scope(), b.scope(),
+            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.session(), b.session(),
                     a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_LONG_INDEX_SCALE),
                     b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_LONG_INDEX_SCALE),
                     length,
@@ -179,7 +179,7 @@ final class BufferMismatch {
         int i = 0;
         if (length > 0 && a.order() == b.order()) {
             if (Double.doubleToRawLongBits(a.get(aOff)) == Double.doubleToRawLongBits(b.get(bOff))) {
-                i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.scope(), b.scope(),
+                i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(a.session(), b.session(),
                         a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE),
                         b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE),
                         length,

src/java.base/share/classes/java/nio/ByteBufferAs-X-Buffer.java.template

@@ -27,8 +27,8 @@
 
 package java.nio;
 
+import java.lang.foreign.MemorySegment;
 import java.util.Objects;
-import jdk.internal.access.foreign.MemorySegmentProxy;
 import jdk.internal.misc.Unsafe;
 
 #if[rw]
@@ -49,7 +49,7 @@ class ByteBufferAs$Type$Buffer$RW$$BO$                  // package-private
 
 #end[rw]
 
-    ByteBufferAs$Type$Buffer$RW$$BO$(ByteBuffer bb, MemorySegmentProxy segment) {   // package-private
+    ByteBufferAs$Type$Buffer$RW$$BO$(ByteBuffer bb, MemorySegment segment) {   // package-private
 #if[rw]
         super(-1, 0,
               bb.remaining() >> $LG_BYTES_PER_VALUE$,
@@ -68,7 +68,7 @@ class ByteBufferAs$Type$Buffer$RW$$BO$                  // package-private
 
     ByteBufferAs$Type$Buffer$RW$$BO$(ByteBuffer bb,
                                      int mark, int pos, int lim, int cap,
-                                     long addr, MemorySegmentProxy segment)
+                                     long addr, MemorySegment segment)
     {
 #if[rw]
         super(mark, pos, lim, cap, segment);
@@ -138,13 +138,13 @@ class ByteBufferAs$Type$Buffer$RW$$BO$                  // package-private
     }
 
     public $type$ get() {
-        $memtype$ x = SCOPED_MEMORY_ACCESS.get$Memtype$Unaligned(scope(), bb.hb, byteOffset(nextGetIndex()),
+        $memtype$ x = SCOPED_MEMORY_ACCESS.get$Memtype$Unaligned(session(), bb.hb, byteOffset(nextGetIndex()),
             {#if[boB]?true:false});
         return $fromBits$(x);
     }
 
     public $type$ get(int i) {
-        $memtype$ x = SCOPED_MEMORY_ACCESS.get$Memtype$Unaligned(scope(), bb.hb, byteOffset(checkIndex(i)),
+        $memtype$ x = SCOPED_MEMORY_ACCESS.get$Memtype$Unaligned(session(), bb.hb, byteOffset(checkIndex(i)),
             {#if[boB]?true:false});
         return $fromBits$(x);
     }
@@ -162,7 +162,7 @@ class ByteBufferAs$Type$Buffer$RW$$BO$                  // package-private
     public $Type$Buffer put($type$ x) {
 #if[rw]
         $memtype$ y = $toBits$(x);
-        SCOPED_MEMORY_ACCESS.put$Memtype$Unaligned(scope(), bb.hb, byteOffset(nextPutIndex()), y,
+        SCOPED_MEMORY_ACCESS.put$Memtype$Unaligned(session(), bb.hb, byteOffset(nextPutIndex()), y,
             {#if[boB]?true:false});
         return this;
 #else[rw]
@@ -173,7 +173,7 @@ class ByteBufferAs$Type$Buffer$RW$$BO$                  // package-private
     public $Type$Buffer put(int i, $type$ x) {
 #if[rw]
         $memtype$ y = $toBits$(x);
-        SCOPED_MEMORY_ACCESS.put$Memtype$Unaligned(scope(), bb.hb, byteOffset(checkIndex(i)), y,
+        SCOPED_MEMORY_ACCESS.put$Memtype$Unaligned(session(), bb.hb, byteOffset(checkIndex(i)), y,
             {#if[boB]?true:false});
         return this;
 #else[rw]

src/java.base/share/classes/java/nio/Direct-X-Buffer-bin.java.template

@@ -33,7 +33,7 @@ class XXX {
 
     private $type$ get$Type$(long a) {
         try {
-            $memtype$ x = SCOPED_MEMORY_ACCESS.get$Memtype$Unaligned(scope(), null, a, bigEndian);
+            $memtype$ x = SCOPED_MEMORY_ACCESS.get$Memtype$Unaligned(session(), null, a, bigEndian);
             return $fromBits$(x);
         } finally {
             Reference.reachabilityFence(this);
@@ -62,7 +62,7 @@ class XXX {
 #if[rw]
         try {
             $memtype$ y = $toBits$(x);
-            SCOPED_MEMORY_ACCESS.put$Memtype$Unaligned(scope(), null, a, y, bigEndian);
+            SCOPED_MEMORY_ACCESS.put$Memtype$Unaligned(session(), null, a, y, bigEndian);
         } finally {
             Reference.reachabilityFence(this);
         }

src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template

@@ -28,10 +28,12 @@
 package java.nio;
 
 import java.io.FileDescriptor;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
 import java.lang.ref.Reference;
 import java.util.Objects;
-import jdk.internal.access.foreign.MemorySegmentProxy;
+import jdk.internal.foreign.MemorySessionImpl;
-import jdk.internal.misc.ScopedMemoryAccess.Scope;
+import jdk.internal.misc.ScopedMemoryAccess.ScopedAccessError;
 import jdk.internal.misc.VM;
 import jdk.internal.ref.Cleaner;
 import sun.nio.ch.DirectBuffer;
@@ -152,7 +154,7 @@ class Direct$Type$Buffer$RW$$BO$
     // Invoked to construct a direct ByteBuffer referring to the block of
     // memory. A given arbitrary object may also be attached to the buffer.
     //
-    Direct$Type$Buffer(long addr, int cap, Object ob, MemorySegmentProxy segment) {
+    Direct$Type$Buffer(long addr, int cap, Object ob, MemorySegment segment) {
         super(-1, 0, cap, cap, segment);
         address = addr;
         cleaner = null;
@@ -162,7 +164,7 @@ class Direct$Type$Buffer$RW$$BO$
     // Invoked to construct a direct ByteBuffer referring to the block of
     // memory. A given arbitrary object may also be attached to the buffer.
     //
-    Direct$Type$Buffer(long addr, int cap, Object ob, FileDescriptor fd, boolean isSync, MemorySegmentProxy segment) {
+    Direct$Type$Buffer(long addr, int cap, Object ob, FileDescriptor fd, boolean isSync, MemorySegment segment) {
         super(-1, 0, cap, cap, fd, isSync, segment);
         address = addr;
         cleaner = null;
@@ -185,7 +187,7 @@ class Direct$Type$Buffer$RW$$BO$
     protected Direct$Type$Buffer$RW$(int cap, long addr,
                                      FileDescriptor fd,
                                      Runnable unmapper,
-                                     boolean isSync, MemorySegmentProxy segment)
+                                     boolean isSync, MemorySegment segment)
     {
 #if[rw]
         super(-1, 0, cap, cap, fd, isSync, segment);
@@ -207,7 +209,7 @@ class Direct$Type$Buffer$RW$$BO$
 #if[byte]
                                FileDescriptor fd, boolean isSync,
 #end[byte]
-                               MemorySegmentProxy segment)
+                               MemorySegment segment)
     {
 #if[rw]
         super(mark, pos, lim, cap,
@@ -306,14 +308,14 @@ class Direct$Type$Buffer$RW$$BO$
 #if[rw]
 
     public long address() {
-        Scope scope = scope();
+        MemorySessionImpl session = session();
-        if (scope != null) {
+        if (session != null) {
-            if (scope.ownerThread() == null) {
+            if (session.ownerThread() == null && session.isCloseable()) {
-                throw new UnsupportedOperationException("ByteBuffer derived from shared segments not supported");
+                throw new UnsupportedOperationException("ByteBuffer derived from closeable shared sessions not supported");
             }
             try {
-                scope.checkValidState();
+                session.checkValidState();
-            } catch (Scope.ScopedAccessError e) {
+            } catch (ScopedAccessError e) {
                 throw new IllegalStateException("This segment is already closed");
             }
         }
@@ -326,7 +328,7 @@ class Direct$Type$Buffer$RW$$BO$
 
     public $type$ get() {
         try {
-            return $fromBits$($swap$(SCOPED_MEMORY_ACCESS.get$Swaptype$(scope(), null, ix(nextGetIndex()))));
+            return $fromBits$($swap$(SCOPED_MEMORY_ACCESS.get$Swaptype$(session(), null, ix(nextGetIndex()))));
         } finally {
             Reference.reachabilityFence(this);
         }
@@ -334,7 +336,7 @@ class Direct$Type$Buffer$RW$$BO$
 
     public $type$ get(int i) {
         try {
-            return $fromBits$($swap$(SCOPED_MEMORY_ACCESS.get$Swaptype$(scope(), null, ix(checkIndex(i)))));
+            return $fromBits$($swap$(SCOPED_MEMORY_ACCESS.get$Swaptype$(session(), null, ix(checkIndex(i)))));
         } finally {
             Reference.reachabilityFence(this);
         }
@@ -354,7 +356,7 @@ class Direct$Type$Buffer$RW$$BO$
     public $Type$Buffer put($type$ x) {
 #if[rw]
         try {
-            SCOPED_MEMORY_ACCESS.put$Swaptype$(scope(), null, ix(nextPutIndex()), $swap$($toBits$(x)));
+            SCOPED_MEMORY_ACCESS.put$Swaptype$(session(), null, ix(nextPutIndex()), $swap$($toBits$(x)));
         } finally {
             Reference.reachabilityFence(this);
         }
@@ -367,7 +369,7 @@ class Direct$Type$Buffer$RW$$BO$
     public $Type$Buffer put(int i, $type$ x) {
 #if[rw]
         try {
-            SCOPED_MEMORY_ACCESS.put$Swaptype$(scope(), null, ix(checkIndex(i)), $swap$($toBits$(x)));
+            SCOPED_MEMORY_ACCESS.put$Swaptype$(session(), null, ix(checkIndex(i)), $swap$($toBits$(x)));
         } finally {
             Reference.reachabilityFence(this);
         }
@@ -384,8 +386,8 @@ class Direct$Type$Buffer$RW$$BO$
         assert (pos <= lim);
         int rem = (pos <= lim ? lim - pos : 0);
         try {
-            // null is passed as destination Scope to avoid checking scope() twice
+            // null is passed as destination MemorySession to avoid checking session() twice
-            SCOPED_MEMORY_ACCESS.copyMemory(scope(), null, null,
+            SCOPED_MEMORY_ACCESS.copyMemory(session(), null, null,
                     ix(pos), null, ix(0), (long)rem << $LG_BYTES_PER_VALUE$);
         } finally {
             Reference.reachabilityFence(this);

src/java.base/share/classes/java/nio/Heap-X-Buffer.java.template

@@ -27,8 +27,8 @@
 
 package java.nio;
 
+import java.lang.foreign.MemorySegment;
 import java.util.Objects;
-import jdk.internal.access.foreign.MemorySegmentProxy;
 
 /**
 #if[rw]
@@ -66,7 +66,7 @@ class Heap$Type$Buffer$RW$
     */
 #end[rw]
 
-    Heap$Type$Buffer$RW$(int cap, int lim, MemorySegmentProxy segment) {            // package-private
+    Heap$Type$Buffer$RW$(int cap, int lim, MemorySegment segment) {            // package-private
 #if[rw]
         super(-1, 0, lim, cap, new $type$[cap], 0, segment);
         /*
@@ -80,7 +80,7 @@ class Heap$Type$Buffer$RW$
 #end[rw]
     }
 
-    Heap$Type$Buffer$RW$($type$[] buf, int off, int len, MemorySegmentProxy segment) { // package-private
+    Heap$Type$Buffer$RW$($type$[] buf, int off, int len, MemorySegment segment) { // package-private
 #if[rw]
         super(-1, off, off + len, buf.length, buf, 0, segment);
         /*
@@ -96,7 +96,7 @@ class Heap$Type$Buffer$RW$
 
     protected Heap$Type$Buffer$RW$($type$[] buf,
                                    int mark, int pos, int lim, int cap,
-                                   int off, MemorySegmentProxy segment)
+                                   int off, MemorySegment segment)
     {
 #if[rw]
         super(mark, pos, lim, cap, buf, off, segment);
@@ -183,7 +183,7 @@ class Heap$Type$Buffer$RW$
 #end[streamableType]
 
     public $Type$Buffer get($type$[] dst, int offset, int length) {
-        checkScope();
+        checkSession();
         Objects.checkFromIndexSize(offset, length, dst.length);
         int pos = position();
         if (length > limit() - pos)
@@ -194,7 +194,7 @@ class Heap$Type$Buffer$RW$
     }
 
     public $Type$Buffer get(int index, $type$[] dst, int offset, int length) {
-        checkScope();
+        checkSession();
         Objects.checkFromIndexSize(index, length, limit());
         Objects.checkFromIndexSize(offset, length, dst.length);
         System.arraycopy(hb, ix(index), dst, offset, length);
@@ -231,7 +231,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer put($type$[] src, int offset, int length) {
 #if[rw]
-        checkScope();
+        checkSession();
         Objects.checkFromIndexSize(offset, length, src.length);
         int pos = position();
         if (length > limit() - pos)
@@ -246,7 +246,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer put($Type$Buffer src) {
 #if[rw]
-        checkScope();
+        checkSession();
         super.put(src);
         return this;
 #else[rw]
@@ -256,7 +256,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer put(int index, $Type$Buffer src, int offset, int length) {
 #if[rw]
-        checkScope();
+        checkSession();
         super.put(index, src, offset, length);
         return this;
 #else[rw]
@@ -266,7 +266,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer put(int index, $type$[] src, int offset, int length) {
 #if[rw]
-        checkScope();
+        checkSession();
         Objects.checkFromIndexSize(index, length, limit());
         Objects.checkFromIndexSize(offset, length, src.length);
         System.arraycopy(src, offset, hb, ix(index), length);
@@ -280,7 +280,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer put(String src, int start, int end) {
 #if[rw]
-        checkScope();
+        checkSession();
         int length = end - start;
         Objects.checkFromIndexSize(start, length, src.length());
         int pos = position();
@@ -335,18 +335,18 @@ class Heap$Type$Buffer$RW$
 #if[rw]
 
     public char getChar() {
-        return SCOPED_MEMORY_ACCESS.getCharUnaligned(scope(), hb, byteOffset(nextGetIndex(2)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getCharUnaligned(session(), hb, byteOffset(nextGetIndex(2)), bigEndian);
     }
 
     public char getChar(int i) {
-        return SCOPED_MEMORY_ACCESS.getCharUnaligned(scope(), hb, byteOffset(checkIndex(i, 2)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getCharUnaligned(session(), hb, byteOffset(checkIndex(i, 2)), bigEndian);
     }
 
 #end[rw]
 
     public $Type$Buffer putChar(char x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putCharUnaligned(scope(), hb, byteOffset(nextPutIndex(2)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putCharUnaligned(session(), hb, byteOffset(nextPutIndex(2)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -355,7 +355,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer putChar(int i, char x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putCharUnaligned(scope(), hb, byteOffset(checkIndex(i, 2)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putCharUnaligned(session(), hb, byteOffset(checkIndex(i, 2)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -387,18 +387,18 @@ class Heap$Type$Buffer$RW$
 #if[rw]
 
     public short getShort() {
-        return SCOPED_MEMORY_ACCESS.getShortUnaligned(scope(), hb, byteOffset(nextGetIndex(2)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getShortUnaligned(session(), hb, byteOffset(nextGetIndex(2)), bigEndian);
     }
 
     public short getShort(int i) {
-        return SCOPED_MEMORY_ACCESS.getShortUnaligned(scope(), hb, byteOffset(checkIndex(i, 2)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getShortUnaligned(session(), hb, byteOffset(checkIndex(i, 2)), bigEndian);
     }
 
 #end[rw]
 
     public $Type$Buffer putShort(short x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putShortUnaligned(scope(), hb, byteOffset(nextPutIndex(2)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putShortUnaligned(session(), hb, byteOffset(nextPutIndex(2)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -407,7 +407,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer putShort(int i, short x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putShortUnaligned(scope(), hb, byteOffset(checkIndex(i, 2)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putShortUnaligned(session(), hb, byteOffset(checkIndex(i, 2)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -439,18 +439,18 @@ class Heap$Type$Buffer$RW$
 #if[rw]
 
     public int getInt() {
-        return SCOPED_MEMORY_ACCESS.getIntUnaligned(scope(), hb, byteOffset(nextGetIndex(4)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getIntUnaligned(session(), hb, byteOffset(nextGetIndex(4)), bigEndian);
     }
 
     public int getInt(int i) {
-        return SCOPED_MEMORY_ACCESS.getIntUnaligned(scope(), hb, byteOffset(checkIndex(i, 4)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getIntUnaligned(session(), hb, byteOffset(checkIndex(i, 4)), bigEndian);
     }
 
 #end[rw]
 
     public $Type$Buffer putInt(int x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putIntUnaligned(scope(), hb, byteOffset(nextPutIndex(4)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putIntUnaligned(session(), hb, byteOffset(nextPutIndex(4)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -459,7 +459,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer putInt(int i, int x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putIntUnaligned(scope(), hb, byteOffset(checkIndex(i, 4)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putIntUnaligned(session(), hb, byteOffset(checkIndex(i, 4)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -491,18 +491,18 @@ class Heap$Type$Buffer$RW$
 #if[rw]
 
     public long getLong() {
-        return SCOPED_MEMORY_ACCESS.getLongUnaligned(scope(), hb, byteOffset(nextGetIndex(8)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getLongUnaligned(session(), hb, byteOffset(nextGetIndex(8)), bigEndian);
     }
 
     public long getLong(int i) {
-        return SCOPED_MEMORY_ACCESS.getLongUnaligned(scope(), hb, byteOffset(checkIndex(i, 8)), bigEndian);
+        return SCOPED_MEMORY_ACCESS.getLongUnaligned(session(), hb, byteOffset(checkIndex(i, 8)), bigEndian);
     }
 
 #end[rw]
 
     public $Type$Buffer putLong(long x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putLongUnaligned(scope(), hb, byteOffset(nextPutIndex(8)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putLongUnaligned(session(), hb, byteOffset(nextPutIndex(8)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -511,7 +511,7 @@ class Heap$Type$Buffer$RW$
 
     public $Type$Buffer putLong(int i, long x) {
 #if[rw]
-        SCOPED_MEMORY_ACCESS.putLongUnaligned(scope(), hb, byteOffset(checkIndex(i, 8)), x, bigEndian);
+        SCOPED_MEMORY_ACCESS.putLongUnaligned(session(), hb, byteOffset(checkIndex(i, 8)), x, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -543,12 +543,12 @@ class Heap$Type$Buffer$RW$
 #if[rw]
 
     public float getFloat() {
-        int x = SCOPED_MEMORY_ACCESS.getIntUnaligned(scope(), hb, byteOffset(nextGetIndex(4)), bigEndian);
+        int x = SCOPED_MEMORY_ACCESS.getIntUnaligned(session(), hb, byteOffset(nextGetIndex(4)), bigEndian);
         return Float.intBitsToFloat(x);
     }
 
     public float getFloat(int i) {
-        int x = SCOPED_MEMORY_ACCESS.getIntUnaligned(scope(), hb, byteOffset(checkIndex(i, 4)), bigEndian);
+        int x = SCOPED_MEMORY_ACCESS.getIntUnaligned(session(), hb, byteOffset(checkIndex(i, 4)), bigEndian);
         return Float.intBitsToFloat(x);
     }
 
@@ -557,7 +557,7 @@ class Heap$Type$Buffer$RW$
     public $Type$Buffer putFloat(float x) {
 #if[rw]
         int y = Float.floatToRawIntBits(x);
-        SCOPED_MEMORY_ACCESS.putIntUnaligned(scope(), hb, byteOffset(nextPutIndex(4)), y, bigEndian);
+        SCOPED_MEMORY_ACCESS.putIntUnaligned(session(), hb, byteOffset(nextPutIndex(4)), y, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -567,7 +567,7 @@ class Heap$Type$Buffer$RW$
     public $Type$Buffer putFloat(int i, float x) {
 #if[rw]
         int y = Float.floatToRawIntBits(x);
-        SCOPED_MEMORY_ACCESS.putIntUnaligned(scope(), hb, byteOffset(checkIndex(i, 4)), y, bigEndian);
+        SCOPED_MEMORY_ACCESS.putIntUnaligned(session(), hb, byteOffset(checkIndex(i, 4)), y, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -599,12 +599,12 @@ class Heap$Type$Buffer$RW$
 #if[rw]
 
     public double getDouble() {
-        long x = SCOPED_MEMORY_ACCESS.getLongUnaligned(scope(), hb, byteOffset(nextGetIndex(8)), bigEndian);
+        long x = SCOPED_MEMORY_ACCESS.getLongUnaligned(session(), hb, byteOffset(nextGetIndex(8)), bigEndian);
         return Double.longBitsToDouble(x);
     }
 
     public double getDouble(int i) {
-        long x = SCOPED_MEMORY_ACCESS.getLongUnaligned(scope(), hb, byteOffset(checkIndex(i, 8)), bigEndian);
+        long x = SCOPED_MEMORY_ACCESS.getLongUnaligned(session(), hb, byteOffset(checkIndex(i, 8)), bigEndian);
         return Double.longBitsToDouble(x);
     }
 
@@ -613,7 +613,7 @@ class Heap$Type$Buffer$RW$
     public $Type$Buffer putDouble(double x) {
 #if[rw]
         long y = Double.doubleToRawLongBits(x);
-        SCOPED_MEMORY_ACCESS.putLongUnaligned(scope(), hb, byteOffset(nextPutIndex(8)), y, bigEndian);
+        SCOPED_MEMORY_ACCESS.putLongUnaligned(session(), hb, byteOffset(nextPutIndex(8)), y, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();
@@ -623,7 +623,7 @@ class Heap$Type$Buffer$RW$
     public $Type$Buffer putDouble(int i, double x) {
 #if[rw]
         long y = Double.doubleToRawLongBits(x);
-        SCOPED_MEMORY_ACCESS.putLongUnaligned(scope(), hb, byteOffset(checkIndex(i, 8)), y, bigEndian);
+        SCOPED_MEMORY_ACCESS.putLongUnaligned(session(), hb, byteOffset(checkIndex(i, 8)), y, bigEndian);
         return this;
 #else[rw]
         throw new ReadOnlyBufferException();

src/java.base/share/classes/java/nio/MappedByteBuffer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,10 +27,10 @@ package java.nio;
 
 import java.io.FileDescriptor;
 import java.io.UncheckedIOException;
+import java.lang.foreign.MemorySegment;
 import java.lang.ref.Reference;
 import java.util.Objects;
 
-import jdk.internal.access.foreign.MemorySegmentProxy;
 import jdk.internal.access.foreign.UnmapperProxy;
 import jdk.internal.misc.ScopedMemoryAccess;
 import jdk.internal.misc.Unsafe;
@@ -96,20 +96,20 @@ public abstract sealed class MappedByteBuffer
     // This should only be invoked by the DirectByteBuffer constructors
     //
     MappedByteBuffer(int mark, int pos, int lim, int cap, // package-private
-                     FileDescriptor fd, boolean isSync, MemorySegmentProxy segment) {
+                     FileDescriptor fd, boolean isSync, MemorySegment segment) {
         super(mark, pos, lim, cap, segment);
         this.fd = fd;
         this.isSync = isSync;
     }
 
     MappedByteBuffer(int mark, int pos, int lim, int cap, // package-private
-                     boolean isSync, MemorySegmentProxy segment) {
+                     boolean isSync, MemorySegment segment) {
         super(mark, pos, lim, cap, segment);
         this.fd = null;
         this.isSync = isSync;
     }
 
-    MappedByteBuffer(int mark, int pos, int lim, int cap, MemorySegmentProxy segment) { // package-private
+    MappedByteBuffer(int mark, int pos, int lim, int cap, MemorySegment segment) { // package-private
         super(mark, pos, lim, cap, segment);
         this.fd = null;
         this.isSync = false;
@@ -189,7 +189,7 @@ public abstract sealed class MappedByteBuffer
         if (fd == null) {
             return true;
         }
-        return SCOPED_MEMORY_ACCESS.isLoaded(scope(), address, isSync, capacity());
+        return SCOPED_MEMORY_ACCESS.isLoaded(session(), address, isSync, capacity());
     }
 
     /**
@@ -207,7 +207,7 @@ public abstract sealed class MappedByteBuffer
             return this;
         }
         try {
-            SCOPED_MEMORY_ACCESS.load(scope(), address, isSync, capacity());
+            SCOPED_MEMORY_ACCESS.load(session(), address, isSync, capacity());
         } finally {
             Reference.reachabilityFence(this);
         }
@@ -307,7 +307,7 @@ public abstract sealed class MappedByteBuffer
         if ((address != 0) && (capacity != 0)) {
             // check inputs
             Objects.checkFromIndexSize(index, length, capacity);
-            SCOPED_MEMORY_ACCESS.force(scope(), fd, address, isSync, index, length);
+            SCOPED_MEMORY_ACCESS.force(session(), fd, address, isSync, index, length);
         }
         return this;
     }

src/java.base/share/classes/java/nio/X-Buffer.java.template

@@ -37,8 +37,8 @@ import java.util.stream.StreamSupport;
 import java.util.stream.$Streamtype$Stream;
 #end[streamableType]
 
+import java.lang.foreign.MemorySegment;
 import java.util.Objects;
-import jdk.internal.access.foreign.MemorySegmentProxy;
 import jdk.internal.util.ArraysSupport;
 
 /**
@@ -293,7 +293,7 @@ public abstract sealed class $Type$Buffer
     // backing array, and array offset
     //
     $Type$Buffer(int mark, int pos, int lim, int cap,   // package-private
-                 $type$[] hb, int offset, MemorySegmentProxy segment)
+                 $type$[] hb, int offset, MemorySegment segment)
     {
         super(mark, pos, lim, cap, segment);
         this.hb = hb;
@@ -302,13 +302,13 @@ public abstract sealed class $Type$Buffer
 
     // Creates a new buffer with the given mark, position, limit, and capacity
     //
-    $Type$Buffer(int mark, int pos, int lim, int cap, MemorySegmentProxy segment) { // package-private
+    $Type$Buffer(int mark, int pos, int lim, int cap, MemorySegment segment) { // package-private
         this(mark, pos, lim, cap, null, 0, segment);
     }
 
     // Creates a new buffer with given base, address and capacity
     //
-    $Type$Buffer($type$[] hb, long addr, int cap, MemorySegmentProxy segment) { // package-private
+    $Type$Buffer($type$[] hb, long addr, int cap, MemorySegment segment) { // package-private
         super(addr, cap, segment);
         this.hb = hb;
         this.offset = 0;
@@ -935,12 +935,12 @@ public abstract sealed class $Type$Buffer
 #if[!byte]
                 if (order() != ByteOrder.nativeOrder())
                     SCOPED_MEMORY_ACCESS.copySwapMemory(
-                            scope(), null, base(), bufAddr,
+                            session(), null, base(), bufAddr,
                             dst, dstOffset, len, $Fulltype$.BYTES);
                 else
 #end[!byte]
                     SCOPED_MEMORY_ACCESS.copyMemory(
-                            scope(), null, base(), bufAddr,
+                            session(), null, base(), bufAddr,
                             dst, dstOffset, len);
             } finally {
                 Reference.reachabilityFence(this);
@@ -1105,12 +1105,12 @@ public abstract sealed class $Type$Buffer
 #if[!byte]
                 if (this.order() != src.order())
                     SCOPED_MEMORY_ACCESS.copySwapMemory(
-                            src.scope(), scope(), srcBase, srcAddr,
+                            src.session(), session(), srcBase, srcAddr,
                             base, addr, len, $Fulltype$.BYTES);
                 else
 #end[!byte]
                     SCOPED_MEMORY_ACCESS.copyMemory(
-                            src.scope(), scope(), srcBase, srcAddr,
+                            src.session(), session(), srcBase, srcAddr,
                             base, addr, len);
             } finally {
                 Reference.reachabilityFence(src);
@@ -1325,12 +1325,12 @@ public abstract sealed class $Type$Buffer
 #if[!byte]
                 if (order() != ByteOrder.nativeOrder())
                     SCOPED_MEMORY_ACCESS.copySwapMemory(
-                            null, scope(), src, srcOffset,
+                            null, session(), src, srcOffset,
                             base(), bufAddr, len, $Fulltype$.BYTES);
                 else
 #end[!byte]
                     SCOPED_MEMORY_ACCESS.copyMemory(
-                            null, scope(), src, srcOffset,
+                            null, session(), src, srcOffset,
                             base(), bufAddr, len);
             } finally {
                 Reference.reachabilityFence(this);

src/java.base/share/classes/java/nio/channels/FileChannel.java

@@ -26,6 +26,8 @@
 package java.nio.channels;
 
 import java.io.IOException;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
 import java.nio.ByteBuffer;
 import java.nio.MappedByteBuffer;
 import java.nio.channels.spi.AbstractInterruptibleChannel;
@@ -38,6 +40,7 @@ import java.nio.file.spi.FileSystemProvider;
 import java.util.Set;
 import java.util.HashSet;
 import java.util.Collections;
+import jdk.internal.javac.PreviewFeature;
 
 /**
  * A channel for reading, writing, mapping, and manipulating a file.
@@ -943,13 +946,13 @@ public abstract class FileChannel
      *
      * @throws NonReadableChannelException
      *         If the {@code mode} is {@link MapMode#READ_ONLY READ_ONLY} or
-     *         an implementation specific map mode requiring read access
+     *         an implementation specific map mode requiring read access,
      *         but this channel was not opened for reading
      *
      * @throws NonWritableChannelException
-     *         If the {@code mode} is {@link MapMode#READ_WRITE READ_WRITE}.
+     *         If the {@code mode} is {@link MapMode#READ_WRITE READ_WRITE},
      *         {@link MapMode#PRIVATE PRIVATE} or an implementation specific
-     *         map mode requiring write access but this channel was not
+     *         map mode requiring write access, but this channel was not
      *         opened for both reading and writing
      *
      * @throws IllegalArgumentException
@@ -967,6 +970,89 @@ public abstract class FileChannel
     public abstract MappedByteBuffer map(MapMode mode, long position, long size)
         throws IOException;
 
+    /**
+     * Maps a region of this channel's file into a new mapped memory segment,
+     * with the given offset, size and memory session.
+     *
+     * <p> If the specified mapping mode is
+     * {@linkplain FileChannel.MapMode#READ_ONLY READ_ONLY}, the resulting
+     * segment will be read-only (see {@link MemorySegment#isReadOnly()}).
+     *
+     * <p> The content of a mapped memory segment can change at any time, for
+     * example if the content of the corresponding region of the mapped file is
+     * changed by this (or another) program.  Whether such changes occur, and
+     * when they occur, is operating-system dependent and therefore unspecified.
+     *
+     * <p> All or part of a mapped memory segment may become inaccessible at any
+     * time, for example if the backing mapped file is truncated. An attempt to
+     * access an inaccessible region of a mapped memory segment will not change
+     * the segment's content and will cause an unspecified exception to be
+     * thrown either at the time of the access or at some later time. It is
+     * therefore strongly recommended that appropriate precautions be taken to
+     * avoid the manipulation of a mapped file by this (or another) program,
+     * except to read or write the file's content.
+     *
+     * @implNote When obtaining a mapped segment from a newly created file
+     *           channel, the initialization state of the contents of the block
+     *           of mapped memory associated with the returned mapped memory
+     *           segment is unspecified and should not be relied upon.
+     *
+     * @param mode
+     *        The file mapping mode, see
+     *        {@link FileChannel#map(FileChannel.MapMode, long, long)};
+     *        the mapping mode might affect the behavior of the returned memory
+     *        mapped segment (see {@link MemorySegment#force()}).
+     *
+     * @param offset
+     *        The offset (expressed in bytes) within the file at which the
+     *        mapped segment is to start.
+     *
+     * @param size
+     *        The size (in bytes) of the mapped memory backing the memory
+     *        segment.
+
+     * @param session
+     *        The segment memory session.
+     *
+     * @return A new mapped memory segment.
+     *
+     * @throws IllegalArgumentException
+     *         If {@code offset < 0}, {@code size < 0} or
+     *         {@code offset + size} overflows the range of {@code long}.
+     *
+     * @throws IllegalStateException
+     *         If the {@code session} is not
+     *         {@linkplain MemorySession#isAlive() alive}, or if access occurs
+     *         from a thread other than the thread
+     *         {@linkplain MemorySession#ownerThread() owning} the
+     *         {@code session}.
+     *
+     * @throws NonReadableChannelException
+     *         If the {@code mode} is {@link MapMode#READ_ONLY READ_ONLY} or
+     *         an implementation specific map mode requiring read access,
+     *         but this channel was not opened for reading.
+     *
+     * @throws NonWritableChannelException
+     *         If the {@code mode} is {@link MapMode#READ_WRITE READ_WRITE},
+     *         {@link MapMode#PRIVATE PRIVATE} or an implementation specific
+     *         map mode requiring write access, but this channel was not
+     *         opened for both reading and writing.
+     *
+     * @throws IOException
+     *         If some other I/O error occurs.
+     *
+     * @throws UnsupportedOperationException
+     *         If an unsupported map mode is specified.
+     *
+     * @since 19
+     */
+    @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
+    public MemorySegment map(MapMode mode, long offset, long size,
+                                      MemorySession session)
+            throws IOException
+    {
+        throw new UnsupportedOperationException();
+    }
 
     // -- Locks --
 

src/java.base/share/classes/jdk/internal/access/JavaLangInvokeAccess.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -82,46 +82,45 @@ public interface JavaLangInvokeAccess {
     Map<String, byte[]> generateHolderClasses(Stream<String> traces);
 
     /**
-     * Returns a var handle view of a given memory address.
+     * Returns a var handle view of a given memory segment.
      * Used by {@code jdk.internal.foreign.LayoutPath} and
-     * {@code jdk.incubator.foreign.MemoryHandles}.
+     * {@code java.lang.invoke.MethodHandles}.
      */
-    VarHandle memoryAccessVarHandle(Class<?> carrier, boolean skipAlignmentMaskCheck, long alignmentMask,
+    VarHandle memorySegmentViewHandle(Class<?> carrier, long alignmentMask, ByteOrder order);
-                                    ByteOrder order);
 
     /**
      * Var handle carrier combinator.
-     * Used by {@code jdk.incubator.foreign.MemoryHandles}.
+     * Used by {@code java.lang.invoke.MethodHandles}.
      */
     VarHandle filterValue(VarHandle target, MethodHandle filterToTarget, MethodHandle filterFromTarget);
 
     /**
      * Var handle filter coordinates combinator.
-     * Used by {@code jdk.incubator.foreign.MemoryHandles}.
+     * Used by {@code java.lang.invoke.MethodHandles}.
      */
     VarHandle filterCoordinates(VarHandle target, int pos, MethodHandle... filters);
 
     /**
      * Var handle drop coordinates combinator.
-     * Used by {@code jdk.incubator.foreign.MemoryHandles}.
+     * Used by {@code java.lang.invoke.MethodHandles}.
      */
     VarHandle dropCoordinates(VarHandle target, int pos, Class<?>... valueTypes);
 
     /**
      * Var handle permute coordinates combinator.
-     * Used by {@code jdk.incubator.foreign.MemoryHandles}.
+     * Used by {@code java.lang.invoke.MethodHandles}.
      */
     VarHandle permuteCoordinates(VarHandle target, List<Class<?>> newCoordinates, int... reorder);
 
     /**
      * Var handle collect coordinates combinator.
-     * Used by {@code jdk.incubator.foreign.MemoryHandles}.
+     * Used by {@code java.lang.invoke.MethodHandles}.
      */
     VarHandle collectCoordinates(VarHandle target, int pos, MethodHandle filter);
 
     /**
      * Var handle insert coordinates combinator.
-     * Used by {@code jdk.incubator.foreign.MemoryHandles}.
+     * Used by {@code java.lang.invoke.MethodHandles}.
      */
     VarHandle insertCoordinates(VarHandle target, int pos, Object... values);
 

src/java.base/share/classes/jdk/internal/access/JavaNioAccess.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,11 +25,10 @@
 
 package jdk.internal.access;
 
-import jdk.internal.access.foreign.MemorySegmentProxy;
 import jdk.internal.access.foreign.UnmapperProxy;
-import jdk.internal.misc.ScopedMemoryAccess.Scope;
 import jdk.internal.misc.VM.BufferPool;
 
+import java.lang.foreign.MemorySegment;
 import java.io.FileDescriptor;
 import java.nio.Buffer;
 import java.nio.ByteBuffer;
@@ -48,7 +47,7 @@ public interface JavaNioAccess {
      * to the resulting buffer.
      * Used by {@code jdk.internal.foreignMemorySegmentImpl}.
      */
-    ByteBuffer newDirectByteBuffer(long addr, int cap, Object obj, MemorySegmentProxy segment);
+    ByteBuffer newDirectByteBuffer(long addr, int cap, Object obj, MemorySegment segment);
 
     /**
      * Constructs a mapped ByteBuffer referring to the block of memory starting
@@ -58,13 +57,13 @@ public interface JavaNioAccess {
      * buffer are derived from the {@code UnmapperProxy}.
      * Used by {@code jdk.internal.foreignMemorySegmentImpl}.
      */
-    ByteBuffer newMappedByteBuffer(UnmapperProxy unmapperProxy, long addr, int cap, Object obj, MemorySegmentProxy segment);
+    ByteBuffer newMappedByteBuffer(UnmapperProxy unmapperProxy, long addr, int cap, Object obj, MemorySegment segment);
 
     /**
      * Constructs an heap ByteBuffer with given backing array, offset, capacity and segment.
      * Used by {@code jdk.internal.foreignMemorySegmentImpl}.
      */
-    ByteBuffer newHeapByteBuffer(byte[] hb, int offset, int capacity, MemorySegmentProxy segment);
+    ByteBuffer newHeapByteBuffer(byte[] hb, int offset, int capacity, MemorySegment segment);
 
     /**
      * Used by {@code jdk.internal.foreign.Utils}.
@@ -84,15 +83,15 @@ public interface JavaNioAccess {
     /**
      * Used by {@code jdk.internal.foreign.AbstractMemorySegmentImpl} and byte buffer var handle views.
      */
-    MemorySegmentProxy bufferSegment(Buffer buffer);
+    MemorySegment bufferSegment(Buffer buffer);
 
     /**
-     * Used by I/O operations to make a buffer's resource scope non-closeable
+     * Used by I/O operations to make a buffer's session non-closeable
-     * (for the duration of the I/O operation) by acquiring a new resource
+     * (for the duration of the I/O operation) by acquiring the session.
-     * scope handle. Null is returned if the buffer has no scope, or
+     * Null is returned if the buffer has no scope, or acquiring is not
-     * acquiring is not required to guarantee safety.
+     * required to guarantee safety.
      */
-    Runnable acquireScope(Buffer buffer, boolean async);
+    Runnable acquireSession(Buffer buffer, boolean async);
 
     /**
      * Used by {@code jdk.internal.foreign.MappedMemorySegmentImpl} and byte buffer var handle views.

src/java.base/share/classes/jdk/internal/access/foreign/MemoryAddressProxy.java

@@ -1,99 +0,0 @@
-/*
- *  Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
- *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- *  This code is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License version 2 only, as
- *  published by the Free Software Foundation.  Oracle designates this
- *  particular file as subject to the "Classpath" exception as provided
- *  by Oracle in the LICENSE file that accompanied this code.
- *
- *  This code is distributed in the hope that it will be useful, but WITHOUT
- *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- *  version 2 for more details (a copy is included in the LICENSE file that
- *  accompanied this code).
- *
- *  You should have received a copy of the GNU General Public License version
- *  2 along with this work; if not, write to the Free Software Foundation,
- *  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *   Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- *  or visit www.oracle.com if you need additional information or have any
- *  questions.
- *
- */
-
-package jdk.internal.access.foreign;
-
-/**
- * This proxy interface is required to allow instances of the {@code MemoryAddress} interface (which is defined inside
- * an incubating module) to be accessed from the memory access var handles.
- */
-public interface MemoryAddressProxy {
-    /**
-     * Check that memory access is within spatial and temporal bounds.
-     * @throws IllegalStateException if underlying segment has been closed already.
-     * @throws IndexOutOfBoundsException if access is out-of-bounds.
-     */
-    void checkAccess(long offset, long length, boolean readOnly);
-    long unsafeGetOffset();
-    Object unsafeGetBase();
-    boolean isSmall();
-
-    /* Helper functions for offset computations. These are required so that we can avoid issuing long opcodes
-     * (e.g. LMUL, LADD) when we're operating on 'small' segments (segments whose length can be expressed with an int).
-     * C2 BCE code is very sensitive to the kind of opcode being emitted, and this workaround allows us to rescue
-     * BCE when working with small segments. This workaround should be dropped when JDK-8223051 is resolved.
-     */
-
-    public static long addOffsets(long op1, long op2, MemoryAddressProxy addr) {
-        if (addr.isSmall()) {
-            // force ints for BCE
-            if (op1 > Integer.MAX_VALUE || op2 > Integer.MAX_VALUE
-                    || op1 < Integer.MIN_VALUE || op2 < Integer.MIN_VALUE) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-            int i1 = (int)op1;
-            int i2 = (int)op2;
-            try {
-                return Math.addExact(i1, i2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-        } else {
-            try {
-                return Math.addExact(op1, op2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Long.MIN_VALUE, Long.MAX_VALUE);
-            }
-        }
-    }
-
-    public static long multiplyOffsets(long op1, long op2, MemoryAddressProxy addr) {
-        if (addr.isSmall()) {
-            if (op1 > Integer.MAX_VALUE || op2 > Integer.MAX_VALUE
-                    || op1 < Integer.MIN_VALUE || op2 < Integer.MIN_VALUE) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-            // force ints for BCE
-            int i1 = (int)op1;
-            int i2 = (int)op2;
-            try {
-                return Math.multiplyExact(i1, i2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-        } else {
-            try {
-                return Math.multiplyExact(op1, op2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Long.MIN_VALUE, Long.MAX_VALUE);
-            }
-        }
-    }
-
-    private static IndexOutOfBoundsException overflowException(long min, long max) {
-        return new IndexOutOfBoundsException(String.format("Overflow occurred during offset computation ; offset exceeded range { %d .. %d }", min, max));
-    }
-}

src/java.base/share/classes/jdk/internal/access/foreign/MemorySegmentProxy.java

@@ -1,104 +0,0 @@
-/*
- *  Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
- *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- *  This code is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License version 2 only, as
- *  published by the Free Software Foundation.  Oracle designates this
- *  particular file as subject to the "Classpath" exception as provided
- *  by Oracle in the LICENSE file that accompanied this code.
- *
- *  This code is distributed in the hope that it will be useful, but WITHOUT
- *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- *  version 2 for more details (a copy is included in the LICENSE file that
- *  accompanied this code).
- *
- *  You should have received a copy of the GNU General Public License version
- *  2 along with this work; if not, write to the Free Software Foundation,
- *  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- *   Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- *  or visit www.oracle.com if you need additional information or have any
- *  questions.
- *
- */
-
-package jdk.internal.access.foreign;
-
-import jdk.internal.misc.ScopedMemoryAccess;
-
-/**
- * This abstract class is required to allow implementations of the {@code MemorySegment} interface (which is defined inside
- * an incubating module) to be accessed from the memory access var handles.
- */
-public abstract class MemorySegmentProxy {
-    /**
-     * Check that memory access is within spatial bounds and that access is compatible with segment access modes.
-     * @throws UnsupportedOperationException if underlying segment has incompatible access modes (e.g. attempting to write
-     * a read-only segment).
-     * @throws IndexOutOfBoundsException if access is out-of-bounds.
-     */
-    public abstract void checkAccess(long offset, long length, boolean readOnly);
-    public abstract long unsafeGetOffset();
-    public abstract Object unsafeGetBase();
-    public abstract boolean isSmall();
-    public abstract ScopedMemoryAccess.Scope scope();
-    public abstract long maxAlignMask();
-
-    /* Helper functions for offset computations. These are required so that we can avoid issuing long opcodes
-     * (e.g. LMUL, LADD) when we're operating on 'small' segments (segments whose length can be expressed with an int).
-     * C2 BCE code is very sensitive to the kind of opcode being emitted, and this workaround allows us to rescue
-     * BCE when working with small segments. This workaround should be dropped when JDK-8223051 is resolved.
-     */
-
-    public static long addOffsets(long op1, long op2, MemorySegmentProxy segmentProxy) {
-        if (segmentProxy.isSmall()) {
-            // force ints for BCE
-            if (op1 > Integer.MAX_VALUE || op2 > Integer.MAX_VALUE
-                    || op1 < Integer.MIN_VALUE || op2 < Integer.MIN_VALUE) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-            int i1 = (int)op1;
-            int i2 = (int)op2;
-            try {
-                return Math.addExact(i1, i2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-        } else {
-            try {
-                return Math.addExact(op1, op2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Long.MIN_VALUE, Long.MAX_VALUE);
-            }
-        }
-    }
-
-    public static long multiplyOffsets(long op1, long op2, MemorySegmentProxy segmentProxy) {
-        if (segmentProxy.isSmall()) {
-            if (op1 > Integer.MAX_VALUE || op2 > Integer.MAX_VALUE
-                    || op1 < Integer.MIN_VALUE || op2 < Integer.MIN_VALUE) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-            // force ints for BCE
-            int i1 = (int)op1;
-            int i2 = (int)op2;
-            try {
-                return Math.multiplyExact(i1, i2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Integer.MIN_VALUE, Integer.MAX_VALUE);
-            }
-        } else {
-            try {
-                return Math.multiplyExact(op1, op2);
-            } catch (ArithmeticException ex) {
-                throw overflowException(Long.MIN_VALUE, Long.MAX_VALUE);
-            }
-        }
-    }
-
-    private static IndexOutOfBoundsException overflowException(long min, long max) {
-        return new IndexOutOfBoundsException(String.format("Overflow occurred during offset computation ; offset exceeded range { %d .. %d }", min, max));
-    }
-}

src/java.base/share/classes/jdk/internal/foreign/AbstractMemorySegmentImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,16 +25,12 @@
 
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.*;
+import java.lang.foreign.MemoryAddress;
-import jdk.internal.access.JavaNioAccess;
+import java.lang.foreign.MemoryLayout;
-import jdk.internal.access.SharedSecrets;
+import java.lang.foreign.MemorySegment;
-import jdk.internal.access.foreign.MemorySegmentProxy;
+import java.lang.foreign.MemorySession;
-import jdk.internal.access.foreign.UnmapperProxy;
+import java.lang.foreign.SegmentAllocator;
-import jdk.internal.misc.ScopedMemoryAccess;
+import java.lang.foreign.ValueLayout;
-import jdk.internal.util.ArraysSupport;
-import jdk.internal.vm.annotation.ForceInline;
-import sun.security.action.GetPropertyAction;
-
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.*;
@@ -43,58 +39,57 @@ import java.util.function.Function;
 import java.util.function.IntFunction;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
+import jdk.internal.access.JavaNioAccess;
+import jdk.internal.access.SharedSecrets;
+import jdk.internal.access.foreign.UnmapperProxy;
+import jdk.internal.misc.ScopedMemoryAccess;
+import jdk.internal.util.ArraysSupport;
+import jdk.internal.vm.annotation.ForceInline;
 
-import static jdk.incubator.foreign.ValueLayout.JAVA_BYTE;
+import static java.lang.foreign.ValueLayout.JAVA_BYTE;
 
 /**
  * This abstract class provides an immutable implementation for the {@code MemorySegment} interface. This class contains information
  * about the segment's spatial and temporal bounds; each memory segment implementation is associated with an owner thread which is set at creation time.
  * Access to certain sensitive operations on the memory segment will fail with {@code IllegalStateException} if the
  * segment is either in an invalid state (e.g. it has already been closed) or if access occurs from a thread other
- * than the owner thread. See {@link ResourceScopeImpl} for more details on management of temporal bounds. Subclasses
+ * than the owner thread. See {@link MemorySessionImpl} for more details on management of temporal bounds. Subclasses
  * are defined for each memory segment kind, see {@link NativeMemorySegmentImpl}, {@link HeapMemorySegmentImpl} and
  * {@link MappedMemorySegmentImpl}.
  */
-public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegmentProxy implements MemorySegment, SegmentAllocator, Scoped {
+public abstract non-sealed class AbstractMemorySegmentImpl implements MemorySegment, SegmentAllocator, Scoped {
 
     private static final ScopedMemoryAccess SCOPED_MEMORY_ACCESS = ScopedMemoryAccess.getScopedMemoryAccess();
 
-    private static final boolean enableSmallSegments =
-            Boolean.parseBoolean(GetPropertyAction.privilegedGetProperty("jdk.incubator.foreign.SmallSegments", "true"));
-
     static final int READ_ONLY = 1;
-    static final int SMALL = READ_ONLY << 1;
     static final long NONCE = new Random().nextLong();
 
+    static final int DEFAULT_MODES = 0;
+
     static final JavaNioAccess nioAccess = SharedSecrets.getJavaNioAccess();
 
     final long length;
     final int mask;
-    final ResourceScopeImpl scope;
+    final MemorySession session;
 
     @ForceInline
-    AbstractMemorySegmentImpl(long length, int mask, ResourceScopeImpl scope) {
+    AbstractMemorySegmentImpl(long length, int mask, MemorySession session) {
         this.length = length;
         this.mask = mask;
-        this.scope = scope;
+        this.session = session;
     }
 
     abstract long min();
 
     abstract Object base();
 
-    abstract AbstractMemorySegmentImpl dup(long offset, long size, int mask, ResourceScopeImpl scope);
+    abstract AbstractMemorySegmentImpl dup(long offset, long size, int mask, MemorySession session);
 
     abstract ByteBuffer makeByteBuffer();
 
-    static int defaultAccessModes(long size) {
-        return (enableSmallSegments && size < Integer.MAX_VALUE) ?
-                SMALL : 0;
-    }
-
     @Override
     public AbstractMemorySegmentImpl asReadOnly() {
-        return dup(0, length, mask | READ_ONLY, scope);
+        return dup(0, length, mask | READ_ONLY, session);
     }
 
     @Override
@@ -115,7 +110,7 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
     }
 
     private AbstractMemorySegmentImpl asSliceNoCheck(long offset, long newSize) {
-        return dup(offset, newSize, mask, scope);
+        return dup(offset, newSize, mask, session);
     }
 
     @Override
@@ -143,12 +138,16 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
     @Override
     public final MemorySegment fill(byte value){
         checkAccess(0, length, false);
-        SCOPED_MEMORY_ACCESS.setMemory(scope, base(), min(), length, value);
+        SCOPED_MEMORY_ACCESS.setMemory(sessionImpl(), base(), min(), length, value);
         return this;
     }
 
     @Override
     public MemorySegment allocate(long bytesSize, long bytesAlignment) {
+        if (bytesAlignment <= 0 ||
+                ((bytesAlignment & (bytesAlignment - 1)) != 0L)) {
+            throw new IllegalArgumentException("Invalid alignment constraint : " + bytesAlignment);
+        }
         return asSlice(0, bytesSize);
     }
 
@@ -170,7 +169,7 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
             if (get(JAVA_BYTE, 0) != that.get(JAVA_BYTE, 0)) {
                 return 0;
             }
-            i = vectorizedMismatchLargeForBytes(scope, that.scope,
+            i = vectorizedMismatchLargeForBytes(sessionImpl(), that.sessionImpl(),
                     this.base(), this.min(),
                     that.base(), that.min(),
                     length);
@@ -192,7 +191,7 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
     /**
      * Mismatch over long lengths.
      */
-    private static long vectorizedMismatchLargeForBytes(ResourceScopeImpl aScope, ResourceScopeImpl bScope,
+    private static long vectorizedMismatchLargeForBytes(MemorySessionImpl aSession, MemorySessionImpl bSession,
                                                         Object a, long aOffset,
                                                         Object b, long bOffset,
                                                         long length) {
@@ -207,7 +206,7 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
                 size = (int) remaining;
                 lastSubRange = true;
             }
-            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(aScope, bScope,
+            i = SCOPED_MEMORY_ACCESS.vectorizedMismatch(aSession, bSession,
                     a, aOffset + off,
                     b, bOffset + off,
                     size, ArraysSupport.LOG2_ARRAY_BYTE_INDEX_SCALE);
@@ -231,7 +230,7 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         checkArraySize("ByteBuffer", 1);
         ByteBuffer _bb = makeByteBuffer();
         if (isSet(READ_ONLY)) {
-            //scope is IMMUTABLE - obtain a RO byte buffer
+            //session is IMMUTABLE - obtain a RO byte buffer
             _bb = _bb.asReadOnlyBuffer();
         }
         return _bb;
@@ -242,14 +241,6 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         return length;
     }
 
-    public final boolean isAlive() {
-        return scope.isAlive();
-    }
-
-    public Thread ownerThread() {
-        return scope.ownerThread();
-    }
-
     @Override
     public boolean isMapped() {
         return false;
@@ -261,7 +252,7 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
     }
 
     @Override
-    public final MemorySegment asOverlappingSlice(MemorySegment other) {
+    public final Optional<MemorySegment> asOverlappingSlice(MemorySegment other) {
         AbstractMemorySegmentImpl that = (AbstractMemorySegmentImpl)Objects.requireNonNull(other);
         if (base() == that.base()) {  // both either native or heap
             final long thisStart = this.min();
@@ -272,10 +263,10 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
             if (thisStart < thatEnd && thisEnd > thatStart) {  //overlap occurs
                 long offsetToThat = this.segmentOffset(that);
                 long newOffset = offsetToThat >= 0 ? offsetToThat : 0;
-                return asSlice(newOffset, Math.min(this.byteSize() - newOffset, that.byteSize() + offsetToThat));
+                return Optional.of(asSlice(newOffset, Math.min(this.byteSize() - newOffset, that.byteSize() + offsetToThat)));
             }
         }
-        return null;
+        return Optional.empty();
     }
 
     @Override
@@ -350,12 +341,6 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         return arr;
     }
 
-    @Override
-    public boolean isSmall() {
-        return isSet(SMALL);
-    }
-
-    @Override
     public void checkAccess(long offset, long length, boolean readOnly) {
         if (!readOnly && isSet(READ_ONLY)) {
             throw new UnsupportedOperationException("Attempt to write a read-only segment");
@@ -363,16 +348,14 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         checkBounds(offset, length);
     }
 
-    void checkValidState() {
+    public void checkValidState() {
-        scope.checkValidStateSlow();
+        sessionImpl().checkValidStateSlow();
     }
 
-    @Override
     public long unsafeGetOffset() {
         return min();
     }
 
-    @Override
     public Object unsafeGetBase() {
         return base();
     }
@@ -383,6 +366,8 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         return (this.mask & mask) != 0;
     }
 
+    public abstract long maxAlignMask();
+
     @ForceInline
     public final boolean isAlignedForElement(long offset, MemoryLayout layout) {
         return (((unsafeGetOffset() + offset) | maxAlignMask()) & (layout.byteAlignment() - 1)) == 0;
@@ -399,32 +384,25 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         return (int)arraySize;
     }
 
-    private void checkBounds(long offset, long length) {
+    @ForceInline
-        if (isSmall() &&
+    void checkBounds(long offset, long length) {
-                offset <= Integer.MAX_VALUE && length <= Integer.MAX_VALUE &&
+        if (length > 0) {
-                offset >= Integer.MIN_VALUE && length >= Integer.MIN_VALUE) {
+            Objects.checkIndex(offset, this.length - length + 1);
-            checkBoundsSmall((int)offset, (int)length);
+        } else if (length < 0 || offset < 0 ||
-        } else if (this != NativeMemorySegmentImpl.EVERYTHING) { // oob not possible for everything segment
+                offset > this.length - length) {
-            if (
-                    length < 0 ||
-                    offset < 0 ||
-                    offset > this.length - length) { // careful of overflow
             throw outOfBoundException(offset, length);
         }
     }
-    }
 
     @Override
-    public ResourceScopeImpl scope() {
+    @ForceInline
-        return scope;
+    public MemorySessionImpl sessionImpl() {
+        return MemorySessionImpl.toSessionImpl(session);
     }
 
-    private void checkBoundsSmall(int offset, int length) {
+    @Override
-        if (length < 0 ||
+    public MemorySession session() {
-                offset < 0 ||
+        return session;
-                offset > (int)this.length - length) { // careful of overflow
-            throw outOfBoundException(offset, length);
-        }
     }
 
     private IndexOutOfBoundsException outOfBoundException(long offset, long length) {
@@ -490,18 +468,9 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
             if (currentIndex < elemCount) {
                 AbstractMemorySegmentImpl acquired = segment;
                 try {
-                    if (acquired.isSmall()) {
-                        int index = (int) currentIndex;
-                        int limit = (int) elemCount;
-                        int elemSize = (int) elementSize;
-                        for (; index < limit; index++) {
-                            action.accept(acquired.asSliceNoCheck(index * elemSize, elemSize));
-                        }
-                    } else {
                     for (long i = currentIndex ; i < elemCount ; i++) {
                         action.accept(acquired.asSliceNoCheck(i * elementSize, elementSize));
                     }
-                    }
                 } finally {
                     currentIndex = elemCount;
                     segment = null;
@@ -527,6 +496,27 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         return "MemorySegment{ id=0x" + Long.toHexString(id()) + " limit: " + length + " }";
     }
 
+    @Override
+    public boolean equals(Object o) {
+        return o instanceof AbstractMemorySegmentImpl that &&
+                isNative() == that.isNative() &&
+                unsafeGetOffset() == that.unsafeGetOffset() &&
+                unsafeGetBase() == that.unsafeGetBase() &&
+                length == that.length &&
+                session.equals(that.session);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(
+                isNative(),
+                unsafeGetOffset(),
+                unsafeGetBase(),
+                length,
+                session
+        );
+    }
+
     public static AbstractMemorySegmentImpl ofBuffer(ByteBuffer bb) {
         Objects.requireNonNull(bb);
         long bbAddress = nioAccess.getBufferAddress(bb);
@@ -538,14 +528,14 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         int size = limit - pos;
 
         AbstractMemorySegmentImpl bufferSegment = (AbstractMemorySegmentImpl)nioAccess.bufferSegment(bb);
-        final ResourceScopeImpl bufferScope;
+        final MemorySessionImpl bufferSession;
         int modes;
         if (bufferSegment != null) {
-            bufferScope = bufferSegment.scope;
+            bufferSession = bufferSegment.sessionImpl();
             modes = bufferSegment.mask;
         } else {
-            bufferScope = ResourceScopeImpl.GLOBAL;
+            bufferSession = MemorySessionImpl.heapSession(bb);
-            modes = defaultAccessModes(size);
+            modes = DEFAULT_MODES;
         }
         if (bb.isReadOnly()) {
             modes |= READ_ONLY;
@@ -553,9 +543,9 @@ public abstract non-sealed class AbstractMemorySegmentImpl extends MemorySegment
         if (base != null) {
             return new HeapMemorySegmentImpl.OfByte(bbAddress + pos, (byte[])base, size, modes);
         } else if (unmapper == null) {
-            return new NativeMemorySegmentImpl(bbAddress + pos, size, modes, bufferScope);
+            return new NativeMemorySegmentImpl(bbAddress + pos, size, modes, bufferSession);
         } else {
-            return new MappedMemorySegmentImpl(bbAddress + pos, unmapper, size, modes, bufferScope);
+            return new MappedMemorySegmentImpl(bbAddress + pos, unmapper, size, modes, bufferSession);
         }
     }
 }

src/java.base/share/classes/jdk/internal/foreign/ArenaAllocator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,9 +25,9 @@
 
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.SegmentAllocator;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.SegmentAllocator;
 
 public final class ArenaAllocator implements SegmentAllocator {
 
@@ -39,12 +39,12 @@ public final class ArenaAllocator implements SegmentAllocator {
     private long size = 0;
     private final long blockSize;
     private final long arenaSize;
-    private final ResourceScope scope;
+    private final MemorySession session;
 
-    public ArenaAllocator(long blockSize, long arenaSize, ResourceScope scope) {
+    public ArenaAllocator(long blockSize, long arenaSize, MemorySession session) {
         this.blockSize = blockSize;
         this.arenaSize = arenaSize;
-        this.scope = scope;
+        this.session = session;
         this.segment = newSegment(blockSize, 1);
     }
 
@@ -60,17 +60,13 @@ public final class ArenaAllocator implements SegmentAllocator {
         }
     }
 
-    public ResourceScope scope() {
-        return scope;
-    }
-
     private MemorySegment newSegment(long bytesSize, long bytesAlignment) {
         long allocatedSize = Utils.alignUp(bytesSize, bytesAlignment);
         if (size + allocatedSize > arenaSize) {
             throw new OutOfMemoryError();
         }
         size += allocatedSize;
-        return MemorySegment.allocateNative(bytesSize, bytesAlignment, scope);
+        return MemorySegment.allocateNative(bytesSize, bytesAlignment, session);
     }
 
     @Override

src/java.base/share/classes/jdk/internal/foreign/CABI.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -25,7 +25,7 @@
  */
 package jdk.internal.foreign;
 
-import static jdk.incubator.foreign.ValueLayout.ADDRESS;
+import static java.lang.foreign.ValueLayout.ADDRESS;
 import static sun.security.action.GetPropertyAction.privilegedGetProperty;
 
 public enum CABI {
@@ -56,7 +56,7 @@ public enum CABI {
                 current = LinuxAArch64;
             }
         } else {
-            throw new ExceptionInInitializerError(
+            throw new UnsupportedOperationException(
                 "Unsupported os, arch, or address size: " + os + ", " + arch + ", " + addressSize);
         }
     }

src/java.base/share/classes/jdk/internal/foreign/ConfinedSession.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,19 +25,19 @@
 
 package jdk.internal.foreign;
 
-import jdk.internal.vm.annotation.ForceInline;
-
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.VarHandle;
 import java.lang.ref.Cleaner;
 
+import jdk.internal.vm.annotation.ForceInline;
+
 /**
- * A confined scope, which features an owner thread. The liveness check features an additional
+ * A confined session, which features an owner thread. The liveness check features an additional
- * confinement check - that is, calling any operation on this scope from a thread other than the
+ * confinement check - that is, calling any operation on this session from a thread other than the
  * owner thread will result in an exception. Because of this restriction, checking the liveness bit
  * can be performed in plain mode.
  */
-final class ConfinedScope extends ResourceScopeImpl {
+final class ConfinedSession extends MemorySessionImpl {
 
     private int asyncReleaseCount = 0;
 
@@ -45,13 +45,13 @@ final class ConfinedScope extends ResourceScopeImpl {
 
     static {
         try {
-            ASYNC_RELEASE_COUNT = MethodHandles.lookup().findVarHandle(ConfinedScope.class, "asyncReleaseCount", int.class);
+            ASYNC_RELEASE_COUNT = MethodHandles.lookup().findVarHandle(ConfinedSession.class, "asyncReleaseCount", int.class);
         } catch (Throwable ex) {
             throw new ExceptionInInitializerError(ex);
         }
     }
 
-    public ConfinedScope(Thread owner, Cleaner cleaner) {
+    public ConfinedSession(Thread owner, Cleaner cleaner) {
         super(owner, new ConfinedResourceList(), cleaner);
     }
 
@@ -65,7 +65,7 @@ final class ConfinedScope extends ResourceScopeImpl {
     public void acquire0() {
         checkValidStateSlow();
         if (state == MAX_FORKS) {
-            throw new IllegalStateException("Scope keep alive limit exceeded");
+            throw new IllegalStateException("Session keep alive limit exceeded");
         }
         state++;
     }
@@ -76,9 +76,9 @@ final class ConfinedScope extends ResourceScopeImpl {
         if (Thread.currentThread() == owner) {
             state--;
         } else {
-            // It is possible to end up here in two cases: this scope was kept alive by some other confined scope
+            // It is possible to end up here in two cases: this session was kept alive by some other confined session
             // which is implicitly released (in which case the release call comes from the cleaner thread). Or,
-            // this scope might be kept alive by a shared scope, which means the release call can come from any
+            // this session might be kept alive by a shared session, which means the release call can come from any
             // thread.
             ASYNC_RELEASE_COUNT.getAndAdd(this, 1);
         }
@@ -89,7 +89,7 @@ final class ConfinedScope extends ResourceScopeImpl {
         if (state == 0 || state - ((int)ASYNC_RELEASE_COUNT.getVolatile(this)) == 0) {
             state = CLOSED;
         } else {
-            throw new IllegalStateException("Scope is kept alive by " + state + " scopes");
+            throw new IllegalStateException("Session is acquired by " + state + " clients");
         }
     }
 

src/java.base/share/classes/jdk/internal/foreign/HeapMemorySegmentImpl.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -26,15 +26,15 @@
 
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
+import java.nio.ByteBuffer;
+import java.util.Objects;
 import jdk.internal.access.JavaNioAccess;
 import jdk.internal.access.SharedSecrets;
 import jdk.internal.misc.Unsafe;
 import jdk.internal.vm.annotation.ForceInline;
 
-import java.nio.ByteBuffer;
-import java.util.Objects;
-
 /**
  * Implementation for heap memory segments. A heap memory segment is composed by an offset and
  * a base object (typically an array). To enhance performances, the access to the base object needs to feature
@@ -44,7 +44,7 @@ import java.util.Objects;
  * the field type storing the 'base' coordinate is just Object; similarly, all the constructor in the subclasses
  * accept an Object 'base' parameter instead of a sharper type (e.g. {@code byte[]}). This is deliberate, as
  * using sharper types would require use of type-conversions, which in turn would inhibit some C2 optimizations,
- * such as the elimination of store barriers in methods like {@link HeapMemorySegmentImpl#dup(long, long, int, ResourceScopeImpl)}.
+ * such as the elimination of store barriers in methods like {@link HeapMemorySegmentImpl#dup(long, long, int, MemorySession)}.
  */
 public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
 
@@ -61,7 +61,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
 
     @ForceInline
     HeapMemorySegmentImpl(long offset, Object base, long length, int mask) {
-        super(length, mask, ResourceScopeImpl.GLOBAL);
+        super(length, mask, MemorySessionImpl.GLOBAL);
         this.offset = offset;
         this.base = base;
     }
@@ -75,7 +75,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
     }
 
     @Override
-    abstract HeapMemorySegmentImpl dup(long offset, long size, int mask, ResourceScopeImpl scope);
+    abstract HeapMemorySegmentImpl dup(long offset, long size, int mask, MemorySession session);
 
     @Override
     ByteBuffer makeByteBuffer() {
@@ -95,7 +95,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
 
         @Override
-        OfByte dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+        OfByte dup(long offset, long size, int mask, MemorySession session) {
             return new OfByte(this.offset + offset, base, size, mask);
         }
 
@@ -107,7 +107,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         public static MemorySegment fromArray(byte[] arr) {
             Objects.requireNonNull(arr);
             long byteSize = (long)arr.length * Unsafe.ARRAY_BYTE_INDEX_SCALE;
-            return new OfByte(Unsafe.ARRAY_BYTE_BASE_OFFSET, arr, byteSize, defaultAccessModes(byteSize));
+            return new OfByte(Unsafe.ARRAY_BYTE_BASE_OFFSET, arr, byteSize, DEFAULT_MODES);
         }
 
         @Override
@@ -123,7 +123,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
 
         @Override
-        OfChar dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+        OfChar dup(long offset, long size, int mask, MemorySession session) {
             return new OfChar(this.offset + offset, base, size, mask);
         }
 
@@ -135,7 +135,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         public static MemorySegment fromArray(char[] arr) {
             Objects.requireNonNull(arr);
             long byteSize = (long)arr.length * Unsafe.ARRAY_CHAR_INDEX_SCALE;
-            return new OfChar(Unsafe.ARRAY_CHAR_BASE_OFFSET, arr, byteSize, defaultAccessModes(byteSize));
+            return new OfChar(Unsafe.ARRAY_CHAR_BASE_OFFSET, arr, byteSize, DEFAULT_MODES);
         }
 
         @Override
@@ -151,7 +151,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
 
         @Override
-        OfShort dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+        OfShort dup(long offset, long size, int mask, MemorySession session) {
             return new OfShort(this.offset + offset, base, size, mask);
         }
 
@@ -163,7 +163,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         public static MemorySegment fromArray(short[] arr) {
             Objects.requireNonNull(arr);
             long byteSize = (long)arr.length * Unsafe.ARRAY_SHORT_INDEX_SCALE;
-            return new OfShort(Unsafe.ARRAY_SHORT_BASE_OFFSET, arr, byteSize, defaultAccessModes(byteSize));
+            return new OfShort(Unsafe.ARRAY_SHORT_BASE_OFFSET, arr, byteSize, DEFAULT_MODES);
         }
 
         @Override
@@ -179,7 +179,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
 
         @Override
-        OfInt dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+        OfInt dup(long offset, long size, int mask, MemorySession session) {
             return new OfInt(this.offset + offset, base, size, mask);
         }
 
@@ -191,7 +191,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         public static MemorySegment fromArray(int[] arr) {
             Objects.requireNonNull(arr);
             long byteSize = (long)arr.length * Unsafe.ARRAY_INT_INDEX_SCALE;
-            return new OfInt(Unsafe.ARRAY_INT_BASE_OFFSET, arr, byteSize, defaultAccessModes(byteSize));
+            return new OfInt(Unsafe.ARRAY_INT_BASE_OFFSET, arr, byteSize, DEFAULT_MODES);
         }
 
         @Override
@@ -207,7 +207,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
 
         @Override
-        OfLong dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+        OfLong dup(long offset, long size, int mask, MemorySession session) {
             return new OfLong(this.offset + offset, base, size, mask);
         }
 
@@ -219,7 +219,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         public static MemorySegment fromArray(long[] arr) {
             Objects.requireNonNull(arr);
             long byteSize = (long)arr.length * Unsafe.ARRAY_LONG_INDEX_SCALE;
-            return new OfLong(Unsafe.ARRAY_LONG_BASE_OFFSET, arr, byteSize, defaultAccessModes(byteSize));
+            return new OfLong(Unsafe.ARRAY_LONG_BASE_OFFSET, arr, byteSize, DEFAULT_MODES);
         }
 
         @Override
@@ -235,7 +235,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
 
         @Override
-        OfFloat dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+        OfFloat dup(long offset, long size, int mask, MemorySession session) {
             return new OfFloat(this.offset + offset, base, size, mask);
         }
 
@@ -247,7 +247,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         public static MemorySegment fromArray(float[] arr) {
             Objects.requireNonNull(arr);
             long byteSize = (long)arr.length * Unsafe.ARRAY_FLOAT_INDEX_SCALE;
-            return new OfFloat(Unsafe.ARRAY_FLOAT_BASE_OFFSET, arr, byteSize, defaultAccessModes(byteSize));
+            return new OfFloat(Unsafe.ARRAY_FLOAT_BASE_OFFSET, arr, byteSize, DEFAULT_MODES);
         }
 
         @Override
@@ -263,7 +263,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
 
         @Override
-        OfDouble dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+        OfDouble dup(long offset, long size, int mask, MemorySession session) {
             return new OfDouble(this.offset + offset, base, size, mask);
         }
 
@@ -275,7 +275,7 @@ public abstract class HeapMemorySegmentImpl extends AbstractMemorySegmentImpl {
         public static MemorySegment fromArray(double[] arr) {
             Objects.requireNonNull(arr);
             long byteSize = (long)arr.length * Unsafe.ARRAY_DOUBLE_INDEX_SCALE;
-            return new OfDouble(Unsafe.ARRAY_DOUBLE_BASE_OFFSET, arr, byteSize, defaultAccessModes(byteSize));
+            return new OfDouble(Unsafe.ARRAY_DOUBLE_BASE_OFFSET, arr, byteSize, DEFAULT_MODES);
         }
 
         @Override

src/java.base/share/classes/jdk/internal/foreign/LayoutPath.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -25,47 +25,33 @@
  */
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.MemoryHandles;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.internal.access.foreign.MemorySegmentProxy;
+import java.lang.foreign.SequenceLayout;
-
+import java.lang.foreign.ValueLayout;
-import jdk.incubator.foreign.GroupLayout;
-import jdk.incubator.foreign.SequenceLayout;
-import jdk.incubator.foreign.ValueLayout;
-
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.lang.invoke.VarHandle;
-import java.util.ArrayDeque;
-import java.util.ArrayList;
-import java.util.Deque;
-import java.util.List;
-import java.util.function.ToLongFunction;
 import java.util.function.UnaryOperator;
 
 /**
- * This class provide support for constructing layout paths; that is, starting from a root path (see {@link #rootPath(MemoryLayout, ToLongFunction)},
+ * This class provide support for constructing layout paths; that is, starting from a root path (see {@link #rootPath(MemoryLayout)},
  * a path can be constructed by selecting layout elements using the selector methods provided by this class
  * (see {@link #sequenceElement()}, {@link #sequenceElement(long)}, {@link #sequenceElement(long, long)}, {@link #groupElement(String)}).
  * Once a path has been fully constructed, clients can ask for the offset associated with the layout element selected
- * by the path (see {@link #offset}), or obtain a memory access var handle to access the selected layout element
+ * by the path (see {@link #offset}), or obtain var handle to access the selected layout element
  * given an address pointing to a segment associated with the root layout (see {@link #dereferenceHandle()}).
  */
 public class LayoutPath {
 
-    private static final MethodHandle ADD_STRIDE;
     private static final MethodHandle MH_ADD_SCALED_OFFSET;
     private static final MethodHandle MH_SLICE;
 
-    private static final int UNSPECIFIED_ELEM_INDEX = -1;
-
     static {
         try {
             MethodHandles.Lookup lookup = MethodHandles.lookup();
-            ADD_STRIDE = lookup.findStatic(LayoutPath.class, "addStride",
-                    MethodType.methodType(long.class, MemorySegment.class, long.class, long.class, long.class));
             MH_ADD_SCALED_OFFSET = lookup.findStatic(LayoutPath.class, "addScaledOffset",
                     MethodType.methodType(long.class, long.class, long.class, long.class));
             MH_SLICE = lookup.findVirtual(MemorySegment.class, "asSlice",
@@ -79,16 +65,12 @@ public class LayoutPath {
     private final long offset;
     private final LayoutPath enclosing;
     private final long[] strides;
-    private final long elementIndex;
-    private final ToLongFunction<MemoryLayout> sizeFunc;
 
-    private LayoutPath(MemoryLayout layout, long offset, long[] strides, long elementIndex, LayoutPath enclosing, ToLongFunction<MemoryLayout> sizeFunc) {
+    private LayoutPath(MemoryLayout layout, long offset, long[] strides, LayoutPath enclosing) {
         this.layout = layout;
         this.offset = offset;
         this.strides = strides;
         this.enclosing = enclosing;
-        this.elementIndex = elementIndex;
-        this.sizeFunc = sizeFunc;
     }
 
     // Layout path selector methods
@@ -97,7 +79,7 @@ public class LayoutPath {
         check(SequenceLayout.class, "attempting to select a sequence element from a non-sequence layout");
         SequenceLayout seq = (SequenceLayout)layout;
         MemoryLayout elem = seq.elementLayout();
-        return LayoutPath.nestedPath(elem, offset, addStride(sizeFunc.applyAsLong(elem)), UNSPECIFIED_ELEM_INDEX, this);
+        return LayoutPath.nestedPath(elem, offset, addStride(elem.bitSize()), this);
     }
 
     public LayoutPath sequenceElement(long start, long step) {
@@ -105,9 +87,8 @@ public class LayoutPath {
         SequenceLayout seq = (SequenceLayout)layout;
         checkSequenceBounds(seq, start);
         MemoryLayout elem = seq.elementLayout();
-        long elemSize = sizeFunc.applyAsLong(elem);
+        long elemSize = elem.bitSize();
-        return LayoutPath.nestedPath(elem, offset + (start * elemSize), addStride(elemSize * step),
+        return LayoutPath.nestedPath(elem, offset + (start * elemSize), addStride(elemSize * step), this);
-                UNSPECIFIED_ELEM_INDEX, this);
     }
 
     public LayoutPath sequenceElement(long index) {
@@ -117,10 +98,10 @@ public class LayoutPath {
         long elemOffset = 0;
         if (index > 0) {
             //if index == 0, we do not depend on sequence element size, so skip
-            long elemSize = sizeFunc.applyAsLong(seq.elementLayout());
+            long elemSize = seq.elementLayout().bitSize();
             elemOffset = elemSize * index;
         }
-        return LayoutPath.nestedPath(seq.elementLayout(), offset + elemOffset, strides, index, this);
+        return LayoutPath.nestedPath(seq.elementLayout(), offset + elemOffset, strides, this);
     }
 
     public LayoutPath groupElement(String name) {
@@ -128,22 +109,20 @@ public class LayoutPath {
         GroupLayout g = (GroupLayout)layout;
         long offset = 0;
         MemoryLayout elem = null;
-        int index = -1;
         for (int i = 0; i < g.memberLayouts().size(); i++) {
             MemoryLayout l = g.memberLayouts().get(i);
             if (l.name().isPresent() &&
                 l.name().get().equals(name)) {
                 elem = l;
-                index = i;
                 break;
             } else if (g.isStruct()) {
-                offset += sizeFunc.applyAsLong(l);
+                offset += l.bitSize();
             }
         }
         if (elem == null) {
             throw badLayoutPath("cannot resolve '" + name + "' in layout " + layout);
         }
-        return LayoutPath.nestedPath(elem, this.offset + offset, strides, index, this);
+        return LayoutPath.nestedPath(elem, this.offset + offset, strides, this);
     }
 
     // Layout path projections
@@ -158,28 +137,16 @@ public class LayoutPath {
         }
         checkAlignment(this);
 
-        List<Class<?>> expectedCoordinates = new ArrayList<>();
+        VarHandle handle = Utils.makeSegmentViewVarHandle(valueLayout);
-        Deque<Integer> perms = new ArrayDeque<>();
+        for (int i = strides.length - 1; i >= 0; i--) {
-        perms.addFirst(0);
+            MethodHandle collector = MethodHandles.insertArguments(MH_ADD_SCALED_OFFSET, 2,
-        expectedCoordinates.add(MemorySegment.class);
+                    Utils.bitsToBytesOrThrow(strides[i], IllegalArgumentException::new));
-
+            // (J, ...) -> J to (J, J, ...) -> J
-        VarHandle handle = Utils.makeMemoryAccessVarHandle(valueLayout, true);
+            // i.e. new coord is prefixed. Last coord will correspond to innermost layout
-
+            handle = MethodHandles.collectCoordinates(handle, 1, collector);
-        for (int i = 0 ; i < strides.length ; i++) {
-            expectedCoordinates.add(long.class);
-            perms.addFirst(0);
-            perms.addLast(i + 1);
-            //add stride
-            handle = MemoryHandles.collectCoordinates(handle, 1 + i,
-                    MethodHandles.insertArguments(ADD_STRIDE, 1, Utils.bitsToBytesOrThrow(strides[strides.length - 1 - i], IllegalStateException::new))); // MS, long, MS_n, long_n, long
-        }
-        //add offset
-        handle = MemoryHandles.insertCoordinates(handle, 1 + strides.length, Utils.bitsToBytesOrThrow(offset, IllegalStateException::new));
-
-        if (strides.length > 0) {
-            // remove duplicate MS args
-            handle = MemoryHandles.permuteCoordinates(handle, expectedCoordinates, perms.stream().mapToInt(i -> i).toArray());
         }
+        handle = MethodHandles.insertCoordinates(handle, 1,
+                Utils.bitsToBytesOrThrow(offset, IllegalArgumentException::new));
         return handle;
     }
 
@@ -219,46 +186,14 @@ public class LayoutPath {
         return layout;
     }
 
-    public MemoryLayout map(UnaryOperator<MemoryLayout> op) {
-        MemoryLayout newLayout = op.apply(layout);
-        if (enclosing == null) {
-            return newLayout;
-        } else if (enclosing.layout instanceof SequenceLayout seq) {
-            if (seq.elementCount().isPresent()) {
-                return enclosing.map(l -> dup(l, MemoryLayout.sequenceLayout(seq.elementCount().getAsLong(), newLayout)));
-            } else {
-                return enclosing.map(l -> dup(l, MemoryLayout.sequenceLayout(newLayout)));
-            }
-        } else if (enclosing.layout instanceof GroupLayout g) {
-            List<MemoryLayout> newElements = new ArrayList<>(g.memberLayouts());
-            //if we selected a layout in a group we must have a valid index
-            newElements.set((int)elementIndex, newLayout);
-            if (g.isUnion()) {
-                return enclosing.map(l -> dup(l, MemoryLayout.unionLayout(newElements.toArray(new MemoryLayout[0]))));
-            } else {
-                return enclosing.map(l -> dup(l, MemoryLayout.structLayout(newElements.toArray(new MemoryLayout[0]))));
-            }
-        } else {
-            return newLayout;
-        }
-    }
-
-    private MemoryLayout dup(MemoryLayout oldLayout, MemoryLayout newLayout) {
-        newLayout = newLayout.withBitAlignment(oldLayout.bitAlignment());
-        if (oldLayout.name().isPresent()) {
-            newLayout.withName(oldLayout.name().get());
-        }
-        return newLayout;
-    }
-
     // Layout path construction
 
-    public static LayoutPath rootPath(MemoryLayout layout, ToLongFunction<MemoryLayout> sizeFunc) {
+    public static LayoutPath rootPath(MemoryLayout layout) {
-        return new LayoutPath(layout, 0L, EMPTY_STRIDES, -1, null, sizeFunc);
+        return new LayoutPath(layout, 0L, EMPTY_STRIDES, null);
     }
 
-    private static LayoutPath nestedPath(MemoryLayout layout, long offset, long[] strides, long elementIndex, LayoutPath encl) {
+    private static LayoutPath nestedPath(MemoryLayout layout, long offset, long[] strides, LayoutPath encl) {
-        return new LayoutPath(layout, offset, strides, elementIndex, encl, encl.sizeFunc);
+        return new LayoutPath(layout, offset, strides, encl);
     }
 
     // Helper methods
@@ -270,8 +205,8 @@ public class LayoutPath {
     }
 
     private void checkSequenceBounds(SequenceLayout seq, long index) {
-        if (seq.elementCount().isPresent() && index >= seq.elementCount().getAsLong()) {
+        if (index >= seq.elementCount()) {
-            throw badLayoutPath(String.format("Sequence index out of bound; found: %d, size: %d", index, seq.elementCount().getAsLong()));
+            throw badLayoutPath(String.format("Sequence index out of bound; found: %d, size: %d", index, seq.elementCount()));
         }
     }
 
@@ -348,9 +283,4 @@ public class LayoutPath {
             return kind;
         }
     }
-
-    private static long addStride(MemorySegment segment, long stride, long base, long index) {
-        return MemorySegmentProxy.addOffsets(base,
-                    MemorySegmentProxy.multiplyOffsets(stride, index, ((MemorySegmentProxy)segment)), (MemorySegmentProxy)segment);
-    }
 }

src/java.base/share/classes/jdk/internal/foreign/MappedMemorySegmentImpl.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.internal.foreign;
+
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
+import java.nio.ByteBuffer;
+import jdk.internal.access.foreign.UnmapperProxy;
+import jdk.internal.misc.ScopedMemoryAccess;
+
+/**
+ * Implementation for a mapped memory segments. A mapped memory segment is a native memory segment, which
+ * additionally features an {@link UnmapperProxy} object. This object provides detailed information about the
+ * memory mapped segment, such as the file descriptor associated with the mapping. This information is crucial
+ * in order to correctly reconstruct a byte buffer object from the segment (see {@link #makeByteBuffer()}).
+ */
+public class MappedMemorySegmentImpl extends NativeMemorySegmentImpl {
+
+    private final UnmapperProxy unmapper;
+
+    static ScopedMemoryAccess SCOPED_MEMORY_ACCESS = ScopedMemoryAccess.getScopedMemoryAccess();
+
+    public MappedMemorySegmentImpl(long min, UnmapperProxy unmapper, long length, int mask, MemorySession session) {
+        super(min, length, mask, session);
+        this.unmapper = unmapper;
+    }
+
+    @Override
+    ByteBuffer makeByteBuffer() {
+        return nioAccess.newMappedByteBuffer(unmapper, min, (int)length, null,
+                session == MemorySessionImpl.GLOBAL ? null : this);
+    }
+
+    @Override
+    MappedMemorySegmentImpl dup(long offset, long size, int mask, MemorySession session) {
+        return new MappedMemorySegmentImpl(min + offset, unmapper, size, mask, session);
+    }
+
+    // mapped segment methods
+
+    @Override
+    public MappedMemorySegmentImpl asSlice(long offset, long newSize) {
+        return (MappedMemorySegmentImpl)super.asSlice(offset, newSize);
+    }
+
+    @Override
+    public boolean isMapped() {
+        return true;
+    }
+
+    // support for mapped segments
+
+    public MemorySegment segment() {
+        return MappedMemorySegmentImpl.this;
+    }
+
+    public void load() {
+        SCOPED_MEMORY_ACCESS.load(sessionImpl(), min, unmapper.isSync(), length);
+    }
+
+    public void unload() {
+        SCOPED_MEMORY_ACCESS.unload(sessionImpl(), min, unmapper.isSync(), length);
+    }
+
+    public boolean isLoaded() {
+        return SCOPED_MEMORY_ACCESS.isLoaded(sessionImpl(), min, unmapper.isSync(), length);
+    }
+
+    public void force() {
+        SCOPED_MEMORY_ACCESS.force(sessionImpl(), unmapper.fileDescriptor(), min, unmapper.isSync(), 0, length);
+    }
+
+    public static class EmptyMappedMemorySegmentImpl extends MappedMemorySegmentImpl {
+
+        public EmptyMappedMemorySegmentImpl(int modes, MemorySession session) {
+            super(0, null, 0, modes, session);
+        }
+
+        @Override
+        public void load() {
+            // do nothing
+        }
+
+        @Override
+        public void unload() {
+            // do nothing
+        }
+
+        @Override
+        public boolean isLoaded() {
+            return true;
+        }
+
+        @Override
+        public void force() {
+            // do nothing
+        }
+    }
+}

src/java.base/share/classes/jdk/internal/foreign/MemoryAddressImpl.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -25,15 +25,14 @@
  */
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.Addressable;
+import java.lang.foreign.Addressable;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ValueLayout;
+import java.lang.foreign.ValueLayout;
 import jdk.internal.foreign.abi.SharedUtils;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
-
 import jdk.internal.vm.annotation.ForceInline;
 
 /**
@@ -87,24 +86,24 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
         return ofLongUnchecked(value, Long.MAX_VALUE);
     }
 
-    public static MemorySegment ofLongUnchecked(long value, long byteSize, ResourceScopeImpl resourceScope) {
+    public static MemorySegment ofLongUnchecked(long value, long byteSize, MemorySession session) {
-        return NativeMemorySegmentImpl.makeNativeSegmentUnchecked(MemoryAddress.ofLong(value), byteSize, resourceScope);
+        return NativeMemorySegmentImpl.makeNativeSegmentUnchecked(MemoryAddress.ofLong(value), byteSize, session);
     }
 
     public static MemorySegment ofLongUnchecked(long value, long byteSize) {
-        return NativeMemorySegmentImpl.makeNativeSegmentUnchecked(MemoryAddress.ofLong(value), byteSize, ResourceScopeImpl.GLOBAL);
+        return NativeMemorySegmentImpl.makeNativeSegmentUnchecked(MemoryAddress.ofLong(value), byteSize, MemorySessionImpl.GLOBAL);
     }
 
     @Override
-    public ResourceScope scope() {
+    public MemorySessionImpl sessionImpl() {
-        return ResourceScopeImpl.GLOBAL;
+        return MemorySessionImpl.GLOBAL;
     }
 
     @Override
     @CallerSensitive
     @ForceInline
     public String getUtf8String(long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getUtf8String");
         SharedUtils.checkAddress(this);
         return NativeMemorySegmentImpl.EVERYTHING.getUtf8String(toRawLongValue() + offset);
     }
@@ -113,7 +112,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @CallerSensitive
     @ForceInline
     public void setUtf8String(long offset, String str) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setUtf8String");
         SharedUtils.checkAddress(this);
         NativeMemorySegmentImpl.EVERYTHING.setUtf8String(toRawLongValue() + offset, str);
     }
@@ -122,7 +121,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public byte get(ValueLayout.OfByte layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -130,7 +129,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfByte layout, long offset, byte value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -138,7 +137,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public boolean get(ValueLayout.OfBoolean layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -146,7 +145,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfBoolean layout, long offset, boolean value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -154,7 +153,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public char get(ValueLayout.OfChar layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -162,7 +161,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfChar layout, long offset, char value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -170,7 +169,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public short get(ValueLayout.OfShort layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -178,7 +177,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfShort layout, long offset, short value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -186,7 +185,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public int get(ValueLayout.OfInt layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -194,7 +193,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfInt layout, long offset, int value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -202,7 +201,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public float get(ValueLayout.OfFloat layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -210,7 +209,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfFloat layout, long offset, float value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -218,7 +217,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public long get(ValueLayout.OfLong layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -226,7 +225,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfLong layout, long offset, long value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -234,7 +233,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public double get(ValueLayout.OfDouble layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -242,7 +241,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfDouble layout, long offset, double value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value);
     }
 
@@ -250,7 +249,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public MemoryAddress get(ValueLayout.OfAddress layout, long offset) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "get");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + offset);
     }
 
@@ -258,7 +257,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void set(ValueLayout.OfAddress layout, long offset, Addressable value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "set");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + offset, value.address());
     }
 
@@ -266,7 +265,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public char getAtIndex(ValueLayout.OfChar layout, long index) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + (index * layout.byteSize()));
     }
@@ -275,7 +274,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void setAtIndex(ValueLayout.OfChar layout, long index, char value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + (index * layout.byteSize()), value);
     }
@@ -284,7 +283,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public short getAtIndex(ValueLayout.OfShort layout, long index) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + (index * layout.byteSize()));
     }
@@ -293,7 +292,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void setAtIndex(ValueLayout.OfShort layout, long index, short value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + (index * layout.byteSize()), value);
     }
@@ -302,7 +301,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public int getAtIndex(ValueLayout.OfInt layout, long index) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + (index * layout.byteSize()));
     }
@@ -311,7 +310,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void setAtIndex(ValueLayout.OfInt layout, long index, int value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + (index * layout.byteSize()), value);
     }
@@ -320,7 +319,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public float getAtIndex(ValueLayout.OfFloat layout, long index) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + (index * layout.byteSize()));
     }
@@ -329,7 +328,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void setAtIndex(ValueLayout.OfFloat layout, long index, float value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + (index * layout.byteSize()), value);
     }
@@ -338,7 +337,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public long getAtIndex(ValueLayout.OfLong layout, long index) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + (index * layout.byteSize()));
     }
@@ -347,7 +346,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void setAtIndex(ValueLayout.OfLong layout, long index, long value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + (index * layout.byteSize()), value);
     }
@@ -356,7 +355,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public double getAtIndex(ValueLayout.OfDouble layout, long index) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + (index * layout.byteSize()));
     }
@@ -365,7 +364,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void setAtIndex(ValueLayout.OfDouble layout, long index, double value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + (index * layout.byteSize()), value);
     }
@@ -374,7 +373,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public MemoryAddress getAtIndex(ValueLayout.OfAddress layout, long index) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "getAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         return NativeMemorySegmentImpl.EVERYTHING.get(layout, toRawLongValue() + (index * layout.byteSize()));
     }
@@ -383,7 +382,7 @@ public final class MemoryAddressImpl implements MemoryAddress, Scoped {
     @ForceInline
     @CallerSensitive
     public void setAtIndex(ValueLayout.OfAddress layout, long index, Addressable value) {
-        Reflection.ensureNativeAccess(Reflection.getCallerClass());
+        Reflection.ensureNativeAccess(Reflection.getCallerClass(), MemoryAddress.class, "setAtIndex");
         Utils.checkElementAlignment(layout, "Layout alignment greater than its size");
         NativeMemorySegmentImpl.EVERYTHING.set(layout, toRawLongValue() + (index * layout.byteSize()), value.address());
     }

src/java.base/share/classes/jdk/internal/foreign/MemorySessionImpl.java

@@ -0,0 +1,463 @@
+/*
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ *  This code is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 only, as
+ *  published by the Free Software Foundation.  Oracle designates this
+ *  particular file as subject to the "Classpath" exception as provided
+ *  by Oracle in the LICENSE file that accompanied this code.
+ *
+ *  This code is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  version 2 for more details (a copy is included in the LICENSE file that
+ *  accompanied this code).
+ *
+ *  You should have received a copy of the GNU General Public License version
+ *  2 along with this work; if not, write to the Free Software Foundation,
+ *  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *   Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ *  or visit www.oracle.com if you need additional information or have any
+ *  questions.
+ *
+ */
+
+package jdk.internal.foreign;
+
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
+import java.lang.foreign.SegmentAllocator;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+import java.lang.ref.Cleaner;
+import java.lang.ref.Reference;
+import java.util.Objects;
+import jdk.internal.misc.ScopedMemoryAccess;
+import jdk.internal.ref.CleanerFactory;
+import jdk.internal.vm.annotation.ForceInline;
+import sun.nio.ch.DirectBuffer;
+
+/**
+ * This class manages the temporal bounds associated with a memory segment as well
+ * as thread confinement. A session has a liveness bit, which is updated when the session is closed
+ * (this operation is triggered by {@link MemorySession#close()}). This bit is consulted prior
+ * to memory access (see {@link #checkValidState()}).
+ * There are two kinds of memory session: confined memory session and shared memory session.
+ * A confined memory session has an associated owner thread that confines some operations to
+ * associated owner thread such as {@link #close()} or {@link #checkValidState()}.
+ * Shared sessions do not feature an owner thread - meaning their operations can be called, in a racy
+ * manner, by multiple threads. To guarantee temporal safety in the presence of concurrent thread,
+ * shared sessions use a more sophisticated synchronization mechanism, which guarantees that no concurrent
+ * access is possible when a session is being closed (see {@link jdk.internal.misc.ScopedMemoryAccess}).
+ */
+public abstract non-sealed class MemorySessionImpl implements Scoped, MemorySession, SegmentAllocator {
+    final ResourceList resourceList;
+    final Cleaner.Cleanable cleanable;
+    final Thread owner;
+
+    static final int OPEN = 0;
+    static final int CLOSING = -1;
+    static final int CLOSED = -2;
+
+    int state = OPEN;
+
+    static final VarHandle STATE;
+
+    static {
+        try {
+            STATE = MethodHandles.lookup().findVarHandle(MemorySessionImpl.class, "state", int.class);
+        } catch (Throwable ex) {
+            throw new ExceptionInInitializerError(ex);
+        }
+    }
+
+    static final int MAX_FORKS = Integer.MAX_VALUE;
+
+    @Override
+    public void addCloseAction(Runnable runnable) {
+        Objects.requireNonNull(runnable);
+        addInternal(runnable instanceof ResourceList.ResourceCleanup cleanup ?
+                cleanup : ResourceList.ResourceCleanup.ofRunnable(runnable));
+    }
+
+    /**
+     * Add a cleanup action. If a failure occurred (because of a add vs. close race), call the cleanup action.
+     * This semantics is useful when allocating new memory segments, since we first do a malloc/mmap and _then_
+     * we register the cleanup (free/munmap) against the session; so, if registration fails, we still have to
+     * cleanup memory. From the perspective of the client, such a failure would manifest as a factory
+     * returning a segment that is already "closed" - which is always possible anyway (e.g. if the session
+     * is closed _after_ the cleanup for the segment is registered but _before_ the factory returns the
+     * new segment to the client). For this reason, it's not worth adding extra complexity to the segment
+     * initialization logic here - and using an optimistic logic works well in practice.
+     */
+    public void addOrCleanupIfFail(ResourceList.ResourceCleanup resource) {
+        try {
+            addInternal(resource);
+        } catch (Throwable ex) {
+            resource.cleanup();
+        }
+    }
+
+    void addInternal(ResourceList.ResourceCleanup resource) {
+        try {
+            checkValidStateSlow();
+            resourceList.add(resource);
+        } catch (ScopedMemoryAccess.ScopedAccessError err) {
+            throw new IllegalStateException("Already closed");
+        }
+    }
+
+    protected MemorySessionImpl(Thread owner, ResourceList resourceList, Cleaner cleaner) {
+        this.owner = owner;
+        this.resourceList = resourceList;
+        cleanable = (cleaner != null) ?
+            cleaner.register(this, resourceList) : null;
+    }
+
+    public static MemorySession createConfined(Thread thread, Cleaner cleaner) {
+        return new ConfinedSession(thread, cleaner);
+    }
+
+    public static MemorySession createShared(Cleaner cleaner) {
+        return new SharedSession(cleaner);
+    }
+
+    public static MemorySessionImpl createImplicit() {
+        return new ImplicitSession();
+    }
+
+    @Override
+    public MemorySegment allocate(long bytesSize, long bytesAlignment) {
+        return MemorySegment.allocateNative(bytesSize, bytesAlignment, this);
+    }
+
+    public abstract void release0();
+
+    public abstract void acquire0();
+
+    @Override
+    public boolean equals(Object o) {
+        return (o instanceof MemorySession other) &&
+            toSessionImpl(other) == this;
+    }
+
+    @Override
+    public int hashCode() {
+        return super.hashCode();
+    }
+
+    @Override
+    public void whileAlive(Runnable action) {
+        Objects.requireNonNull(action);
+        acquire0();
+        try {
+            action.run();
+        } finally {
+            release0();
+        }
+    }
+
+    /**
+     * Returns "owner" thread of this session.
+     * @return owner thread (or null for a shared session)
+     */
+    public final Thread ownerThread() {
+        return owner;
+    }
+
+    /**
+     * Returns true, if this session is still open. This method may be called in any thread.
+     * @return {@code true} if this session is not closed yet.
+     */
+    public abstract boolean isAlive();
+
+    @Override
+    public MemorySession asNonCloseable() {
+        return isCloseable() ?
+                new NonCloseableView(this) : this;
+    }
+
+    public static MemorySessionImpl toSessionImpl(MemorySession session) {
+        return ((Scoped)session).sessionImpl();
+    }
+
+    @Override
+    public MemorySessionImpl sessionImpl() {
+        return this;
+    }
+
+    /**
+     * This is a faster version of {@link #checkValidStateSlow()}, which is called upon memory access, and which
+     * relies on invariants associated with the memory session implementations (volatile access
+     * to the closed state bit is replaced with plain access). This method should be monomorphic,
+     * to avoid virtual calls in the memory access hot path. This method is not intended as general purpose method
+     * and should only be used in the memory access handle hot path; for liveness checks triggered by other API methods,
+     * please use {@link #checkValidStateSlow()}.
+     */
+    @ForceInline
+    public final void checkValidState() {
+        if (owner != null && owner != Thread.currentThread()) {
+            throw new IllegalStateException("Attempted access outside owning thread");
+        }
+        if (state < OPEN) {
+            throw ScopedMemoryAccess.ScopedAccessError.INSTANCE;
+        }
+    }
+
+    /**
+     * Checks that this session is still alive (see {@link #isAlive()}).
+     * @throws IllegalStateException if this session is already closed or if this is
+     * a confined session and this method is called outside of the owner thread.
+     */
+    public final void checkValidStateSlow() {
+        if (owner != null && Thread.currentThread() != owner) {
+            throw new IllegalStateException("Attempted access outside owning thread");
+        } else if (!isAlive()) {
+            throw new IllegalStateException("Already closed");
+        }
+    }
+
+    @Override
+    protected Object clone() throws CloneNotSupportedException {
+        throw new CloneNotSupportedException();
+    }
+
+    @Override
+    public boolean isCloseable() {
+        return true;
+    }
+
+    /**
+     * Closes this session, executing any cleanup action (where provided).
+     * @throws IllegalStateException if this session is already closed or if this is
+     * a confined session and this method is called outside of the owner thread.
+     */
+    @Override
+    public void close() {
+        try {
+            justClose();
+            if (cleanable != null) {
+                cleanable.clean();
+            } else {
+                resourceList.cleanup();
+            }
+        } finally {
+            Reference.reachabilityFence(this);
+        }
+    }
+
+    abstract void justClose();
+
+    /**
+     * The global, non-closeable, shared session. Similar to a shared session, but its {@link #close()} method throws unconditionally.
+     * Adding new resources to the global session, does nothing: as the session can never become not-alive, there is nothing to track.
+     * Acquiring and or releasing a memory session similarly does nothing.
+     */
+    static class GlobalSessionImpl extends MemorySessionImpl {
+
+        final Object ref;
+
+        public GlobalSessionImpl(Object ref) {
+            super(null, null ,null);
+            this.ref = ref;
+        }
+
+        @Override
+        @ForceInline
+        public void release0() {
+            // do nothing
+        }
+
+        @Override
+        public boolean isCloseable() {
+            return false;
+        }
+
+        @Override
+        @ForceInline
+        public void acquire0() {
+            // do nothing
+        }
+
+        @Override
+        void addInternal(ResourceList.ResourceCleanup resource) {
+            // do nothing
+        }
+
+        @Override
+        public boolean isAlive() {
+            return true;
+        }
+
+        @Override
+        public void justClose() {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    public static final MemorySessionImpl GLOBAL = new GlobalSessionImpl(null);
+
+    public static MemorySessionImpl heapSession(Object ref) {
+        return new GlobalSessionImpl(ref);
+    }
+
+    /**
+     * This is an implicit, GC-backed memory session. Implicit sessions cannot be closed explicitly.
+     * While it would be possible to model an implicit session as a non-closeable view of a shared
+     * session, it is better to capture the fact that an implicit session is not just a non-closeable
+     * view of some session which might be closeable. This is useful e.g. in the implementations of
+     * {@link DirectBuffer#address()}, where obtaining an address of a buffer instance associated
+     * with a potentially closeable session is forbidden.
+     */
+    static class ImplicitSession extends SharedSession {
+
+        public ImplicitSession() {
+            super(CleanerFactory.cleaner());
+        }
+
+        @Override
+        public void release0() {
+            Reference.reachabilityFence(this);
+        }
+
+        @Override
+        public void acquire0() {
+            // do nothing
+        }
+
+        @Override
+        public boolean isCloseable() {
+            return false;
+        }
+
+        @Override
+        public boolean isAlive() {
+            return true;
+        }
+
+        @Override
+        public MemorySession asNonCloseable() {
+            return this;
+        }
+
+        @Override
+        public void justClose() {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    /**
+     * This is a non-closeable view of another memory session. Instances of this class are used in resource session
+     * accessors (see {@link MemorySegment#session()}). This class forwards all session methods to the underlying
+     * "root" session implementation, and throws {@link UnsupportedOperationException} on close. This class contains
+     * a strong reference to the original session, so even if the original session is dropped by the client
+     * it would still be reachable by the GC, which is important if the session is implicitly closed.
+     */
+    public final static class NonCloseableView implements MemorySession, Scoped {
+        final MemorySessionImpl session;
+
+        public NonCloseableView(MemorySessionImpl session) {
+            this.session = session;
+        }
+
+        public MemorySessionImpl sessionImpl() {
+            return session;
+        }
+
+        @Override
+        public boolean isAlive() {
+            return session.isAlive();
+        }
+
+        @Override
+        public boolean isCloseable() {
+            return false;
+        }
+
+        @Override
+        public Thread ownerThread() {
+            return session.ownerThread();
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            return session.equals(o);
+        }
+
+        @Override
+        public int hashCode() {
+            return session.hashCode();
+        }
+
+        @Override
+        public void whileAlive(Runnable action) {
+            session.whileAlive(action);
+        }
+
+        @Override
+        public MemorySession asNonCloseable() {
+            return this;
+        }
+
+        @Override
+        public void addCloseAction(Runnable runnable) {
+            session.addCloseAction(runnable);
+        }
+
+        @Override
+        public void close() {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    /**
+     * A list of all cleanup actions associated with a memory session. Cleanup actions are modelled as instances
+     * of the {@link ResourceCleanup} class, and, together, form a linked list. Depending on whether a session
+     * is shared or confined, different implementations of this class will be used, see {@link ConfinedSession.ConfinedResourceList}
+     * and {@link SharedSession.SharedResourceList}.
+     */
+    public abstract static class ResourceList implements Runnable {
+        ResourceCleanup fst;
+
+        abstract void add(ResourceCleanup cleanup);
+
+        abstract void cleanup();
+
+        public final void run() {
+            cleanup(); // cleaner interop
+        }
+
+        static void cleanup(ResourceCleanup first) {
+            ResourceCleanup current = first;
+            while (current != null) {
+                current.cleanup();
+                current = current.next;
+            }
+        }
+
+        public abstract static class ResourceCleanup {
+            ResourceCleanup next;
+
+            public abstract void cleanup();
+
+            static final ResourceCleanup CLOSED_LIST = new ResourceCleanup() {
+                @Override
+                public void cleanup() {
+                    throw new IllegalStateException("This resource list has already been closed!");
+                }
+            };
+
+            static ResourceCleanup ofRunnable(Runnable cleanupAction) {
+                return new ResourceCleanup() {
+                    @Override
+                    public void cleanup() {
+                        cleanupAction.run();
+                    }
+                };
+            }
+        }
+
+    }
+}

src/java.base/share/classes/jdk/internal/foreign/NativeMemorySegmentImpl.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -26,22 +26,32 @@
 
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
+import java.nio.ByteBuffer;
 import jdk.internal.misc.Unsafe;
 import jdk.internal.misc.VM;
 import jdk.internal.vm.annotation.ForceInline;
 import sun.security.action.GetBooleanAction;
 
-import java.nio.ByteBuffer;
-
 /**
  * Implementation for native memory segments. A native memory segment is essentially a wrapper around
  * a native long address.
  */
 public class NativeMemorySegmentImpl extends AbstractMemorySegmentImpl {
 
-    public static final MemorySegment EVERYTHING = makeNativeSegmentUnchecked(MemoryAddress.NULL, Long.MAX_VALUE, ResourceScopeImpl.GLOBAL);
+    public static final MemorySegment EVERYTHING = new NativeMemorySegmentImpl(0, Long.MAX_VALUE, 0, MemorySessionImpl.GLOBAL) {
+        @Override
+        void checkBounds(long offset, long length) {
+            // do nothing
+        }
+
+        @Override
+        NativeMemorySegmentImpl dup(long offset, long size, int mask, MemorySession scope) {
+            throw new IllegalStateException();
+        }
+    };
 
     private static final Unsafe unsafe = Unsafe.getUnsafe();
 
@@ -54,8 +64,8 @@ public class NativeMemorySegmentImpl extends AbstractMemorySegmentImpl {
     final long min;
 
     @ForceInline
-    NativeMemorySegmentImpl(long min, long length, int mask, ResourceScopeImpl scope) {
+    NativeMemorySegmentImpl(long min, long length, int mask, MemorySession session) {
-        super(length, mask, scope);
+        super(length, mask, session);
         this.min = min;
     }
 
@@ -67,14 +77,14 @@ public class NativeMemorySegmentImpl extends AbstractMemorySegmentImpl {
     }
 
     @Override
-    NativeMemorySegmentImpl dup(long offset, long size, int mask, ResourceScopeImpl scope) {
+    NativeMemorySegmentImpl dup(long offset, long size, int mask, MemorySession session) {
-        return new NativeMemorySegmentImpl(min + offset, size, mask, scope);
+        return new NativeMemorySegmentImpl(min + offset, size, mask, session);
     }
 
     @Override
     ByteBuffer makeByteBuffer() {
         return nioAccess.newDirectByteBuffer(min(), (int) this.length, null,
-                scope == ResourceScopeImpl.GLOBAL ? null : this);
+                session == MemorySessionImpl.GLOBAL ? null : this);
     }
 
     @Override
@@ -99,14 +109,15 @@ public class NativeMemorySegmentImpl extends AbstractMemorySegmentImpl {
 
     // factories
 
-    public static MemorySegment makeNativeSegment(long bytesSize, long alignmentBytes, ResourceScopeImpl scope) {
+    public static MemorySegment makeNativeSegment(long bytesSize, long alignmentBytes, MemorySession session) {
-        scope.checkValidStateSlow();
+        MemorySessionImpl sessionImpl = MemorySessionImpl.toSessionImpl(session);
+        sessionImpl.checkValidStateSlow();
         if (VM.isDirectMemoryPageAligned()) {
             alignmentBytes = Math.max(alignmentBytes, nioAccess.pageSize());
         }
-        long alignedSize = alignmentBytes > MAX_MALLOC_ALIGN ?
+        long alignedSize = Math.max(1L, alignmentBytes > MAX_MALLOC_ALIGN ?
                 bytesSize + (alignmentBytes - 1) :
-                bytesSize;
+                bytesSize);
 
         nioAccess.reserveMemory(alignedSize, bytesSize);
 
@@ -116,8 +127,8 @@ public class NativeMemorySegmentImpl extends AbstractMemorySegmentImpl {
         }
         long alignedBuf = Utils.alignUp(buf, alignmentBytes);
         AbstractMemorySegmentImpl segment = new NativeMemorySegmentImpl(buf, alignedSize,
-                defaultAccessModes(alignedSize), scope);
+                DEFAULT_MODES, session);
-        scope.addOrCleanupIfFail(new ResourceScopeImpl.ResourceList.ResourceCleanup() {
+        sessionImpl.addOrCleanupIfFail(new MemorySessionImpl.ResourceList.ResourceCleanup() {
             @Override
             public void cleanup() {
                 unsafe.freeMemory(buf);
@@ -131,9 +142,10 @@ public class NativeMemorySegmentImpl extends AbstractMemorySegmentImpl {
         return segment;
     }
 
-    public static MemorySegment makeNativeSegmentUnchecked(MemoryAddress min, long bytesSize, ResourceScopeImpl scope) {
+    public static MemorySegment makeNativeSegmentUnchecked(MemoryAddress min, long bytesSize, MemorySession session) {
-        scope.checkValidStateSlow();
+        MemorySessionImpl sessionImpl = MemorySessionImpl.toSessionImpl(session);
-        AbstractMemorySegmentImpl segment = new NativeMemorySegmentImpl(min.toRawLongValue(), bytesSize, defaultAccessModes(bytesSize), scope);
+        sessionImpl.checkValidStateSlow();
+        AbstractMemorySegmentImpl segment = new NativeMemorySegmentImpl(min.toRawLongValue(), bytesSize, DEFAULT_MODES, session);
         return segment;
     }
 }

src/java.base/share/classes/jdk/internal/foreign/PlatformLayouts.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2020, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -25,8 +25,8 @@
  */
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.ValueLayout;
+import java.lang.foreign.ValueLayout;
 
 public class PlatformLayouts {
     public static <Z extends MemoryLayout> Z pick(Z sysv, Z win64, Z aarch64) {

src/java.base/share/classes/jdk/internal/foreign/Scoped.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,8 +25,6 @@
 
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.ResourceScope;
-
 public interface Scoped {
-    ResourceScope scope();
+    MemorySessionImpl sessionImpl();
 }

src/java.base/share/classes/jdk/internal/foreign/SharedSession.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,27 +25,26 @@
 
 package jdk.internal.foreign;
 
-import jdk.internal.misc.ScopedMemoryAccess;
-import jdk.internal.vm.annotation.ForceInline;
-
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.VarHandle;
 import java.lang.ref.Cleaner;
+import jdk.internal.misc.ScopedMemoryAccess;
+import jdk.internal.vm.annotation.ForceInline;
 
 /**
- * A shared scope, which can be shared across multiple threads. Closing a shared scope has to ensure that
+ * A shared session, which can be shared across multiple threads. Closing a shared session has to ensure that
- * (i) only one thread can successfully close a scope (e.g. in a close vs. close race) and that
+ * (i) only one thread can successfully close a session (e.g. in a close vs. close race) and that
- * (ii) no other thread is accessing the memory associated with this scope while the segment is being
+ * (ii) no other thread is accessing the memory associated with this session while the segment is being
  * closed. To ensure the former condition, a CAS is performed on the liveness bit. Ensuring the latter
  * is trickier, and require a complex synchronization protocol (see {@link jdk.internal.misc.ScopedMemoryAccess}).
  * Since it is the responsibility of the closing thread to make sure that no concurrent access is possible,
  * checking the liveness bit upon access can be performed in plain mode, as in the confined case.
  */
-class SharedScope extends ResourceScopeImpl {
+class SharedSession extends MemorySessionImpl {
 
     private static final ScopedMemoryAccess SCOPED_MEMORY_ACCESS = ScopedMemoryAccess.getScopedMemoryAccess();
 
-    SharedScope(Cleaner cleaner) {
+    SharedSession(Cleaner cleaner) {
         super(null, new SharedResourceList(), cleaner);
     }
 
@@ -55,12 +54,12 @@ class SharedScope extends ResourceScopeImpl {
         int value;
         do {
             value = (int) STATE.getVolatile(this);
-            if (value < ALIVE) {
+            if (value < OPEN) {
-                //segment is not alive!
+                //segment is not open!
                 throw new IllegalStateException("Already closed");
             } else if (value == MAX_FORKS) {
                 //overflow
-                throw new IllegalStateException("Scope keep alive limit exceeded");
+                throw new IllegalStateException("Session acquire limit exceeded");
             }
         } while (!STATE.compareAndSet(this, value, value + 1));
     }
@@ -71,7 +70,7 @@ class SharedScope extends ResourceScopeImpl {
         int value;
         do {
             value = (int) STATE.getVolatile(this);
-            if (value <= ALIVE) {
+            if (value <= OPEN) {
                 //cannot get here - we can't close segment twice
                 throw new IllegalStateException("Already closed");
             }
@@ -79,16 +78,16 @@ class SharedScope extends ResourceScopeImpl {
     }
 
     void justClose() {
-        int prevState = (int) STATE.compareAndExchange(this, ALIVE, CLOSING);
+        int prevState = (int) STATE.compareAndExchange(this, OPEN, CLOSING);
         if (prevState < 0) {
             throw new IllegalStateException("Already closed");
-        } else if (prevState != ALIVE) {
+        } else if (prevState != OPEN) {
-            throw new IllegalStateException("Scope is kept alive by " + prevState + " scopes");
+            throw new IllegalStateException("Session is acquired by " + prevState + " clients");
         }
         boolean success = SCOPED_MEMORY_ACCESS.closeScope(this);
-        STATE.setVolatile(this, success ? CLOSED : ALIVE);
+        STATE.setVolatile(this, success ? CLOSED : OPEN);
         if (!success) {
-            throw new IllegalStateException("Cannot close while another thread is accessing the segment");
+            throw new IllegalStateException("Session is acquired by 1 client");
         }
     }
 
@@ -130,7 +129,7 @@ class SharedScope extends ResourceScopeImpl {
 
         void cleanup() {
             // At this point we are only interested about add vs. close races - not close vs. close
-            // (because MemoryScope::justClose ensured that this thread won the race to close the scope).
+            // (because MemorySessionImpl::justClose ensured that this thread won the race to close the session).
             // So, the only "bad" thing that could happen is that some other thread adds to this list
             // while we're closing it.
             if (FST.getAcquire(this) != ResourceCleanup.CLOSED_LIST) {

src/java.base/share/classes/jdk/internal/foreign/SystemLookup.java

@@ -25,24 +25,21 @@
 
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.SymbolLookup;
+import java.lang.foreign.SymbolLookup;
-import jdk.incubator.foreign.MemoryAddress;
-import jdk.internal.loader.NativeLibrary;
-import jdk.internal.loader.RawNativeLibraries;
-
 import java.lang.invoke.MethodHandles;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
-
+import jdk.internal.loader.NativeLibrary;
+import jdk.internal.loader.RawNativeLibraries;
 import sun.security.action.GetPropertyAction;
 
-import static jdk.incubator.foreign.ValueLayout.ADDRESS;
+import static java.lang.foreign.ValueLayout.ADDRESS;
 
 public class SystemLookup implements SymbolLookup {
 
@@ -50,14 +47,28 @@ public class SystemLookup implements SymbolLookup {
 
     static final SystemLookup INSTANCE = new SystemLookup();
 
+    /* A fallback lookup, used when creation of system lookup fails. */
+    private static final SymbolLookup fallbackLookup = name -> Optional.empty();
+
     /*
      * On POSIX systems, dlsym will allow us to lookup symbol in library dependencies; the same trick doesn't work
      * on Windows. For this reason, on Windows we do not generate any side-library, and load msvcrt.dll directly instead.
      */
-    private static final SymbolLookup syslookup = switch (CABI.current()) {
+    private static final SymbolLookup syslookup = makeSystemLookup();
+
+    private static final SymbolLookup makeSystemLookup() {
+        try {
+            return switch (CABI.current()) {
                 case SysV, LinuxAArch64, MacOsAArch64 -> libLookup(libs -> libs.load(jdkLibraryPath("syslookup")));
                 case Win64 -> makeWindowsLookup(); // out of line to workaround javac crash
             };
+        } catch (Throwable ex) {
+            // This can happen in the event of a library loading failure - e.g. if one of the libraries the
+            // system lookup depends on cannot be loaded for some reason. In such extreme cases, rather than
+            // fail, return a dummy lookup.
+            return fallbackLookup;
+        }
+    }
 
     private static SymbolLookup makeWindowsLookup() {
         Path system32 = Path.of(System.getenv("SystemRoot"), "System32");
@@ -70,17 +81,19 @@ public class SystemLookup implements SymbolLookup {
 
         if (useUCRT) {
             // use a fallback lookup to look up inline functions from fallback lib
-            SymbolLookup fallbackLibLookup = libLookup(libs -> libs.load(jdkLibraryPath("WinFallbackLookup")));
+
+            SymbolLookup fallbackLibLookup =
+                    libLookup(libs -> libs.load(jdkLibraryPath("syslookup")));
 
             int numSymbols = WindowsFallbackSymbols.values().length;
             MemorySegment funcs = MemorySegment.ofAddress(fallbackLibLookup.lookup("funcs").orElseThrow().address(),
-                ADDRESS.byteSize() * numSymbols, ResourceScope.globalScope());
+                ADDRESS.byteSize() * numSymbols, MemorySession.global());
 
-            SymbolLookup fallbackLookup = name -> Optional.ofNullable(WindowsFallbackSymbols.valueOfOrNull(name))
+            Function<String, Optional<MemorySegment>> fallbackLookup = name -> Optional.ofNullable(WindowsFallbackSymbols.valueOfOrNull(name))
-                .map(symbol -> NativeSymbol.ofAddress(symbol.name(), funcs.getAtIndex(ADDRESS, symbol.ordinal()), ResourceScope.globalScope()));
+                .map(symbol -> MemorySegment.ofAddress(funcs.getAtIndex(ADDRESS, symbol.ordinal()), 0L, MemorySession.global()));
 
             final SymbolLookup finalLookup = lookup;
-            lookup = name -> finalLookup.lookup(name).or(() -> fallbackLookup.lookup(name));
+            lookup = name -> finalLookup.lookup(name).or(() -> fallbackLookup.apply(name));
         }
 
         return lookup;
@@ -94,7 +107,7 @@ public class SystemLookup implements SymbolLookup {
                 long addr = lib.lookup(name);
                 return addr == 0 ?
                         Optional.empty() :
-                        Optional.of(NativeSymbol.ofAddress(name, MemoryAddress.ofLong(addr), ResourceScope.globalScope()));
+                        Optional.of(MemorySegment.ofAddress(MemoryAddress.ofLong(addr), 0, MemorySession.global()));
             } catch (NoSuchMethodException e) {
                 return Optional.empty();
             }
@@ -114,15 +127,16 @@ public class SystemLookup implements SymbolLookup {
         return javahome.resolve(lib).resolve(libname);
     }
 
-    @Override
-    public Optional<NativeSymbol> lookup(String name) {
-        return syslookup.lookup(name);
-    }
 
     public static SystemLookup getInstance() {
         return INSTANCE;
     }
 
+    @Override
+    public Optional<MemorySegment> lookup(String name) {
+        return syslookup.lookup(name);
+    }
+
     // fallback symbols missing from ucrtbase.dll
     // this list has to be kept in sync with the table in the companion native library
     private enum WindowsFallbackSymbols {

src/java.base/share/classes/jdk/internal/foreign/Utils.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
+ *  Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
  *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  *  This code is free software; you can redistribute it and/or modify it
@@ -26,11 +26,11 @@
 
 package jdk.internal.foreign;
 
-import jdk.incubator.foreign.*;
+import java.lang.foreign.MemoryAddress;
-import jdk.internal.access.SharedSecrets;
+import java.lang.foreign.MemoryLayout;
-import jdk.internal.access.foreign.MemorySegmentProxy;
+import java.lang.foreign.MemorySegment;
-import jdk.internal.vm.annotation.ForceInline;
+import java.lang.foreign.SegmentAllocator;
-
+import java.lang.foreign.ValueLayout;
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
@@ -38,19 +38,14 @@ import java.lang.invoke.VarHandle;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Supplier;
-
+import jdk.internal.access.SharedSecrets;
-import static jdk.incubator.foreign.ValueLayout.JAVA_BYTE;
+import jdk.internal.vm.annotation.ForceInline;
-import static sun.security.action.GetPropertyAction.*;
+import static java.lang.foreign.ValueLayout.JAVA_BYTE;
 
 /**
  * This class contains misc helper functions to support creation of memory segments.
  */
 public final class Utils {
-    // used when testing invoke exact behavior of memory access handles
-    private static final boolean SHOULD_ADAPT_HANDLES
-        = Boolean.parseBoolean(privilegedGetProperty("jdk.internal.foreign.SHOULD_ADAPT_HANDLES", "true"));
-
-    private static final MethodHandle SEGMENT_FILTER;
     private static final MethodHandle BYTE_TO_BOOL;
     private static final MethodHandle BOOL_TO_BYTE;
     private static final MethodHandle ADDRESS_TO_LONG;
@@ -63,8 +58,6 @@ public final class Utils {
     static {
         try {
             MethodHandles.Lookup lookup = MethodHandles.lookup();
-            SEGMENT_FILTER = lookup.findStatic(Utils.class, "filterSegment",
-                    MethodType.methodType(MemorySegmentProxy.class, MemorySegment.class));
             BYTE_TO_BOOL = lookup.findStatic(Utils.class, "byteToBoolean",
                     MethodType.methodType(boolean.class, byte.class));
             BOOL_TO_BYTE = lookup.findStatic(Utils.class, "booleanToByte",
@@ -105,13 +98,12 @@ public final class Utils {
         }
     }
 
-    public static VarHandle makeMemoryAccessVarHandle(ValueLayout layout, boolean skipAlignmentCheck) {
+    public static VarHandle makeSegmentViewVarHandle(ValueLayout layout) {
         class VarHandleCache {
             private static final Map<ValueLayout, VarHandle> handleMap = new ConcurrentHashMap<>();
-            private static final Map<ValueLayout, VarHandle> handleMapNoAlignCheck = new ConcurrentHashMap<>();
 
-            static VarHandle put(ValueLayout layout, VarHandle handle, boolean skipAlignmentCheck) {
+            static VarHandle put(ValueLayout layout, VarHandle handle) {
-                VarHandle prev = (skipAlignmentCheck ? handleMapNoAlignCheck : handleMap).putIfAbsent(layout, handle);
+                VarHandle prev = handleMap.putIfAbsent(layout, handle);
                 return prev != null ? prev : handle;
             }
         }
@@ -126,26 +118,17 @@ public final class Utils {
             baseCarrier = byte.class;
         }
 
-        VarHandle handle = SharedSecrets.getJavaLangInvokeAccess().memoryAccessVarHandle(baseCarrier, skipAlignmentCheck,
+        VarHandle handle = SharedSecrets.getJavaLangInvokeAccess().memorySegmentViewHandle(baseCarrier,
                 layout.byteAlignment() - 1, layout.order());
 
-        // This adaptation is required, otherwise the memory access var handle will have type MemorySegmentProxy,
-        // and not MemorySegment (which the user expects), which causes performance issues with asType() adaptations.
-        handle = SHOULD_ADAPT_HANDLES
-            ? MemoryHandles.filterCoordinates(handle, 0, SEGMENT_FILTER)
-            : handle;
         if (layout.carrier() == boolean.class) {
-            handle = MemoryHandles.filterValue(handle, BOOL_TO_BYTE, BYTE_TO_BOOL);
+            handle = MethodHandles.filterValue(handle, BOOL_TO_BYTE, BYTE_TO_BOOL);
         } else if (layout.carrier() == MemoryAddress.class) {
-            handle = MemoryHandles.filterValue(handle,
+            handle = MethodHandles.filterValue(handle,
                     MethodHandles.explicitCastArguments(ADDRESS_TO_LONG, MethodType.methodType(baseCarrier, MemoryAddress.class)),
                     MethodHandles.explicitCastArguments(LONG_TO_ADDRESS, MethodType.methodType(MemoryAddress.class, baseCarrier)));
         }
-        return VarHandleCache.put(layout, handle, skipAlignmentCheck);
+        return VarHandleCache.put(layout, handle);
-    }
-
-    private static MemorySegmentProxy filterSegment(MemorySegment segment) {
-        return (AbstractMemorySegmentImpl)segment;
     }
 
     private static boolean byteToBoolean(byte b) {
@@ -168,12 +151,6 @@ public final class Utils {
         return addr;
     }
 
-    @ForceInline
-    public static long scaleOffset(MemorySegment segment, long index, long size) {
-        // note: we know size is a small value (as it comes from ValueLayout::byteSize())
-        return MemorySegmentProxy.multiplyOffsets(index, (int)size, (AbstractMemorySegmentImpl)segment);
-    }
-
     @ForceInline
     public static boolean isAligned(long offset, long align) {
         return (offset & (align - 1)) == 0;
@@ -181,7 +158,7 @@ public final class Utils {
 
     @ForceInline
     public static void checkElementAlignment(MemoryLayout layout, String msg) {
-        if (layout.byteAlignment() > layout.byteSize()) {
+        if (layout.bitAlignment() > layout.bitSize()) {
             throw new IllegalArgumentException(msg);
         }
     }

src/java.base/share/classes/jdk/internal/foreign/abi/Binding.java

@@ -24,16 +24,14 @@
  */
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.Addressable;
+import java.lang.foreign.Addressable;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryHandles;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.SegmentAllocator;
-import jdk.incubator.foreign.SegmentAllocator;
+import java.lang.foreign.ValueLayout;
-import jdk.incubator.foreign.ValueLayout;
 import jdk.internal.foreign.MemoryAddressImpl;
-import jdk.internal.foreign.ResourceScopeImpl;
 
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
@@ -232,36 +230,36 @@ public abstract class Binding {
     /**
      * A binding context is used as an helper to carry out evaluation of certain bindings; for instance,
      * it helps {@link Allocate} bindings, by providing the {@link SegmentAllocator} that should be used for
-     * the allocation operation, or {@link ToSegment} bindings, by providing the {@link ResourceScope} that
+     * the allocation operation, or {@link ToSegment} bindings, by providing the {@link MemorySession} that
      * should be used to create an unsafe struct from a memory address.
      */
     public static class Context implements AutoCloseable {
         private final SegmentAllocator allocator;
-        private final ResourceScope scope;
+        private final MemorySession session;
 
-        private Context(SegmentAllocator allocator, ResourceScope scope) {
+        private Context(SegmentAllocator allocator, MemorySession session) {
             this.allocator = allocator;
-            this.scope = scope;
+            this.session = session;
         }
 
         public SegmentAllocator allocator() {
             return allocator;
         }
 
-        public ResourceScope scope() {
+        public MemorySession session() {
-            return scope;
+            return session;
         }
 
         @Override
         public void close() {
-            scope().close();
+            session().close();
         }
 
         /**
          * Create a binding context from given native scope.
          */
         public static Context ofBoundedAllocator(long size) {
-            ResourceScope scope = ResourceScope.newConfinedScope();
+            MemorySession scope = MemorySession.openConfined();
             return new Context(SegmentAllocator.newNativeArena(size, scope), scope);
         }
 
@@ -272,7 +270,7 @@ public abstract class Binding {
         public static Context ofAllocator(SegmentAllocator allocator) {
             return new Context(allocator, null) {
                 @Override
-                public ResourceScope scope() {
+                public MemorySession session() {
                     throw new UnsupportedOperationException();
                 }
             };
@@ -283,7 +281,7 @@ public abstract class Binding {
          * the context's allocator is accessed.
          */
         public static Context ofScope() {
-            ResourceScope scope = ResourceScope.newConfinedScope();
+            MemorySession scope = MemorySession.openConfined();
             return new Context(null, scope) {
                 @Override
                 public SegmentAllocator allocator() { throw new UnsupportedOperationException(); }
@@ -301,7 +299,7 @@ public abstract class Binding {
             }
 
             @Override
-            public ResourceScope scope() {
+            public MemorySession session() {
                 throw new UnsupportedOperationException();
             }
 
@@ -630,7 +628,7 @@ public abstract class Binding {
             // copies of e.g. 2 int fields of a struct as a single long, while the struct is only
             // 4-byte-aligned (since it only contains ints)
             ValueLayout layout = MemoryLayout.valueLayout(type(), ByteOrder.nativeOrder()).withBitAlignment(8);
-            return MemoryHandles.insertCoordinates(MemoryHandles.varHandle(layout), 1, offset);
+            return MethodHandles.insertCoordinates(MethodHandles.memorySegmentViewVarHandle(layout), 1, offset);
         }
     }
 
@@ -970,7 +968,7 @@ public abstract class Binding {
         }
 
         private static MemorySegment toSegment(MemoryAddress operand, long size, Context context) {
-            return MemoryAddressImpl.ofLongUnchecked(operand.toRawLongValue(), size, (ResourceScopeImpl) context.scope);
+            return MemoryAddressImpl.ofLongUnchecked(operand.toRawLongValue(), size, context.session);
         }
 
         @Override

src/java.base/share/classes/jdk/internal/foreign/abi/BufferLayout.java

@@ -24,8 +24,8 @@
  */
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.ValueLayout;
+import java.lang.foreign.ValueLayout;
 import jdk.internal.foreign.MemoryAddressImpl;
 
 import java.io.PrintStream;
@@ -45,12 +45,12 @@ class BufferLayout {
     final long[] input_type_offsets;
     final long[] output_type_offsets;
 
-    private final Map<jdk.internal.foreign.abi.VMStorage, Long> argOffsets;
+    private final Map<VMStorage, Long> argOffsets;
-    private final Map<jdk.internal.foreign.abi.VMStorage, Long> retOffsets;
+    private final Map<VMStorage, Long> retOffsets;
 
     private BufferLayout(long size, long arguments_next_pc, long stack_args_bytes, long stack_args,
                          long[] input_type_offsets, long[] output_type_offsets,
-                         Map<jdk.internal.foreign.abi.VMStorage, Long> argOffsets, Map<jdk.internal.foreign.abi.VMStorage, Long> retOffsets) {
+                         Map<VMStorage, Long> argOffsets, Map<VMStorage, Long> retOffsets) {
         this.size = size;
         this.arguments_next_pc = arguments_next_pc;
         this.stack_args_bytes = stack_args_bytes;
@@ -76,25 +76,25 @@ class BufferLayout {
         long stack_args = offset;
         offset += 8;
 
-        Map<jdk.internal.foreign.abi.VMStorage, Long> argOffsets = new HashMap<>();
+        Map<VMStorage, Long> argOffsets = new HashMap<>();
         long[] input_type_offsets = new long[abi.inputStorage.length];
         for (int i = 0; i < abi.inputStorage.length; i++) {
             long size = abi.arch.typeSize(i);
             offset = SharedUtils.alignUp(offset, size);
             input_type_offsets[i] = offset;
-            for (jdk.internal.foreign.abi.VMStorage store : abi.inputStorage[i]) {
+            for (VMStorage store : abi.inputStorage[i]) {
                 argOffsets.put(store, offset);
                 offset += size;
             }
         }
 
-        Map<jdk.internal.foreign.abi.VMStorage, Long> retOffsets = new HashMap<>();
+        Map<VMStorage, Long> retOffsets = new HashMap<>();
         long[] output_type_offsets = new long[abi.outputStorage.length];
         for (int i = 0; i < abi.outputStorage.length; i++) {
             long size = abi.arch.typeSize(i);
             offset = SharedUtils.alignUp(offset, size);
             output_type_offsets[i] = offset;
-            for (jdk.internal.foreign.abi.VMStorage store : abi.outputStorage[i]) {
+            for (VMStorage store : abi.outputStorage[i]) {
                 retOffsets.put(store, offset);
                 offset += size;
             }
@@ -104,11 +104,11 @@ class BufferLayout {
                 input_type_offsets, output_type_offsets, argOffsets, retOffsets);
     }
 
-    long argOffset(jdk.internal.foreign.abi.VMStorage storage) {
+    long argOffset(VMStorage storage) {
         return argOffsets.get(storage);
     }
 
-    long retOffset(jdk.internal.foreign.abi.VMStorage storage) {
+    long retOffset(VMStorage storage) {
         return retOffsets.get(storage);
     }
 
@@ -116,8 +116,8 @@ class BufferLayout {
         return Long.toHexString((long) VH_LONG.get(buffer.asSlice(offset)));
     }
 
-    private void dumpValues(jdk.internal.foreign.abi.Architecture arch, MemorySegment buff, PrintStream stream,
+    private void dumpValues(Architecture arch, MemorySegment buff, PrintStream stream,
-                                   Map<jdk.internal.foreign.abi.VMStorage, Long> offsets) {
+                            Map<VMStorage, Long> offsets) {
         for (var entry : offsets.entrySet()) {
             VMStorage storage = entry.getKey();
             stream.print(storage.name());

src/java.base/share/classes/jdk/internal/foreign/abi/CallingSequence.java

@@ -24,7 +24,7 @@
  */
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
 
 import java.lang.invoke.MethodType;
 import java.util.List;

src/java.base/share/classes/jdk/internal/foreign/abi/CallingSequenceBuilder.java

@@ -24,8 +24,8 @@
  */
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
 import sun.security.action.GetPropertyAction;
 
 import java.lang.invoke.MethodType;
@@ -40,7 +40,7 @@ import static jdk.internal.foreign.abi.Binding.Tag.*;
 
 public class CallingSequenceBuilder {
     private static final boolean VERIFY_BINDINGS = Boolean.parseBoolean(
-            GetPropertyAction.privilegedGetProperty("jdk.incubator.foreign.VERIFY_BINDINGS", "true"));
+            GetPropertyAction.privilegedGetProperty("java.lang.foreign.VERIFY_BINDINGS", "true"));
 
     private boolean isTrivial;
     private final boolean forUpcall;

src/java.base/share/classes/jdk/internal/foreign/abi/ProgrammableInvoker.java

@@ -24,12 +24,11 @@
  */
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.Addressable;
+import java.lang.foreign.Addressable;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.SegmentAllocator;
-import jdk.incubator.foreign.SegmentAllocator;
+import java.lang.foreign.ValueLayout;
-import jdk.incubator.foreign.ValueLayout;
 import jdk.internal.access.JavaLangInvokeAccess;
 import jdk.internal.access.SharedSecrets;
 import jdk.internal.invoke.NativeEntryPoint;
@@ -86,10 +85,10 @@ public class ProgrammableInvoker {
             MH_INVOKE_MOVES = lookup.findVirtual(ProgrammableInvoker.class, "invokeMoves",
                     methodType(Object.class, long.class, Object[].class, Binding.VMStore[].class, Binding.VMLoad[].class));
             MH_INVOKE_INTERP_BINDINGS = lookup.findVirtual(ProgrammableInvoker.class, "invokeInterpBindings",
-                    methodType(Object.class, NativeSymbol.class, SegmentAllocator.class, Object[].class, MethodHandle.class, Map.class, Map.class));
+                    methodType(Object.class, Addressable.class, SegmentAllocator.class, Object[].class, MethodHandle.class, Map.class, Map.class));
             MH_WRAP_ALLOCATOR = lookup.findStatic(Binding.Context.class, "ofAllocator",
                     methodType(Binding.Context.class, SegmentAllocator.class));
-            MH_ADDR_TO_LONG = lookup.findStatic(ProgrammableInvoker.class, "unboxTargetAddress", methodType(long.class, NativeSymbol.class));
+            MH_ADDR_TO_LONG = lookup.findStatic(ProgrammableInvoker.class, "unboxTargetAddress", methodType(long.class, Addressable.class));
         } catch (ReflectiveOperationException e) {
             throw new RuntimeException(e);
         }
@@ -171,7 +170,7 @@ public class ProgrammableInvoker {
         return handle;
     }
 
-    private static long unboxTargetAddress(NativeSymbol addr) {
+    private static long unboxTargetAddress(Addressable addr) {
         SharedUtils.checkSymbol(addr);
         return addr.address().toRawLongValue();
     }
@@ -262,10 +261,10 @@ public class ProgrammableInvoker {
      */
     Object invokeMoves(long addr, Object[] args, Binding.VMStore[] argBindings, Binding.VMLoad[] returnBindings) {
         MemorySegment stackArgsSeg = null;
-        try (ResourceScope scope = ResourceScope.newConfinedScope()) {
+        try (MemorySession session = MemorySession.openConfined()) {
-            MemorySegment argBuffer = MemorySegment.allocateNative(layout.size, 64, scope);
+            MemorySegment argBuffer = MemorySegment.allocateNative(layout.size, 64, session);
             if (stackArgsBytes > 0) {
-                stackArgsSeg = MemorySegment.allocateNative(stackArgsBytes, 8, scope);
+                stackArgsSeg = MemorySegment.allocateNative(stackArgsBytes, 8, session);
             }
 
             VH_LONG.set(argBuffer.asSlice(layout.arguments_next_pc), addr);
@@ -311,7 +310,7 @@ public class ProgrammableInvoker {
         }
     }
 
-    Object invokeInterpBindings(NativeSymbol symbol, SegmentAllocator allocator, Object[] args, MethodHandle leaf,
+    Object invokeInterpBindings(Addressable symbol, SegmentAllocator allocator, Object[] args, MethodHandle leaf,
                                 Map<VMStorage, Integer> argIndexMap,
                                 Map<VMStorage, Integer> retIndexMap) throws Throwable {
         Binding.Context unboxContext = bufferCopySize != 0

src/java.base/share/classes/jdk/internal/foreign/abi/ProgrammableUpcallHandler.java

@@ -25,11 +25,10 @@
 
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.ValueLayout;
-import jdk.incubator.foreign.ValueLayout;
 import jdk.internal.access.JavaLangInvokeAccess;
 import jdk.internal.access.SharedSecrets;
 import jdk.internal.foreign.MemoryAddressImpl;
@@ -46,7 +45,6 @@ import java.util.Objects;
 import java.util.stream.Stream;
 
 import static java.lang.invoke.MethodHandles.dropArguments;
-import static java.lang.invoke.MethodHandles.exactInvoker;
 import static java.lang.invoke.MethodHandles.filterReturnValue;
 import static java.lang.invoke.MethodHandles.identity;
 import static java.lang.invoke.MethodHandles.insertArguments;
@@ -89,7 +87,7 @@ public class ProgrammableUpcallHandler {
         }
     }
 
-    public static NativeSymbol make(ABIDescriptor abi, MethodHandle target, CallingSequence callingSequence, ResourceScope scope) {
+    public static MemorySegment make(ABIDescriptor abi, MethodHandle target, CallingSequence callingSequence, MemorySession session) {
         Binding.VMLoad[] argMoves = argMoveBindings(callingSequence);
         Binding.VMStore[] retMoves = retMoveBindings(callingSequence);
 
@@ -135,7 +133,7 @@ public class ProgrammableUpcallHandler {
             MethodHandle invokeMoves = insertArguments(MH_invokeMoves, 1, doBindingsErased, argMoves, retMoves, abi, layout);
             entryPoint = allocateUpcallStub(invokeMoves, abi, layout);
         }
-        return UpcallStubs.makeUpcall(entryPoint, scope);
+        return UpcallStubs.makeUpcall(entryPoint, session);
     }
 
     private static void checkPrimitive(MethodType type) {

src/java.base/share/classes/jdk/internal/foreign/abi/SharedUtils.java

@@ -24,31 +24,30 @@
  */
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.Addressable;
+import java.lang.foreign.Addressable;
-import jdk.incubator.foreign.CLinker;
+import java.lang.foreign.Linker;
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.GroupLayout;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.SegmentAllocator;
-import jdk.incubator.foreign.SegmentAllocator;
+import java.lang.foreign.SequenceLayout;
-import jdk.incubator.foreign.SequenceLayout;
+import java.lang.foreign.VaList;
-import jdk.incubator.foreign.VaList;
+import java.lang.foreign.ValueLayout;
-import jdk.incubator.foreign.ValueLayout;
+import jdk.internal.foreign.abi.aarch64.linux.LinuxAArch64Linker;
+import jdk.internal.foreign.abi.x64.sysv.SysVx64Linker;
+import jdk.internal.foreign.abi.x64.windows.Windowsx64Linker;
 import jdk.internal.access.JavaLangAccess;
 import jdk.internal.access.JavaLangInvokeAccess;
 import jdk.internal.access.SharedSecrets;
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.foreign.Scoped;
 import jdk.internal.foreign.CABI;
 import jdk.internal.foreign.MemoryAddressImpl;
-import jdk.internal.foreign.ResourceScopeImpl;
 import jdk.internal.foreign.Utils;
-import jdk.internal.foreign.abi.aarch64.linux.LinuxAArch64Linker;
 import jdk.internal.foreign.abi.aarch64.macos.MacOsAArch64Linker;
-import jdk.internal.foreign.abi.x64.sysv.SysVx64Linker;
-import jdk.internal.foreign.abi.x64.windows.Windowsx64Linker;
 import jdk.internal.vm.annotation.ForceInline;
 
 import java.lang.invoke.MethodHandle;
@@ -78,15 +77,14 @@ import static java.lang.invoke.MethodHandles.insertArguments;
 import static java.lang.invoke.MethodHandles.permuteArguments;
 import static java.lang.invoke.MethodHandles.tryFinally;
 import static java.lang.invoke.MethodType.methodType;
-import static jdk.incubator.foreign.ValueLayout.ADDRESS;
+import static java.lang.foreign.ValueLayout.JAVA_BOOLEAN;
-import static jdk.incubator.foreign.ValueLayout.JAVA_BOOLEAN;
+import static java.lang.foreign.ValueLayout.JAVA_BYTE;
-import static jdk.incubator.foreign.ValueLayout.JAVA_BYTE;
+import static java.lang.foreign.ValueLayout.JAVA_CHAR;
-import static jdk.incubator.foreign.ValueLayout.JAVA_CHAR;
+import static java.lang.foreign.ValueLayout.JAVA_DOUBLE;
-import static jdk.incubator.foreign.ValueLayout.JAVA_DOUBLE;
+import static java.lang.foreign.ValueLayout.JAVA_FLOAT;
-import static jdk.incubator.foreign.ValueLayout.JAVA_FLOAT;
+import static java.lang.foreign.ValueLayout.JAVA_INT;
-import static jdk.incubator.foreign.ValueLayout.JAVA_INT;
+import static java.lang.foreign.ValueLayout.JAVA_LONG;
-import static jdk.incubator.foreign.ValueLayout.JAVA_LONG;
+import static java.lang.foreign.ValueLayout.JAVA_SHORT;
-import static jdk.incubator.foreign.ValueLayout.JAVA_SHORT;
 
 public class SharedUtils {
 
@@ -174,7 +172,7 @@ public class SharedUtils {
     }
 
     private static long alignmentOfArray(SequenceLayout ar, boolean isVar) {
-        if (ar.elementCount().orElseThrow() == 0) {
+        if (ar.elementCount() == 0) {
             // VLA or incomplete
             return 16;
         } else if ((ar.byteSize()) >= 16 && isVar) {
@@ -269,7 +267,7 @@ public class SharedUtils {
         throw new IllegalArgumentException("No type for size: " + size + " isFloat=" + useFloat);
     }
 
-    public static CLinker getSystemLinker() {
+    public static Linker getSystemLinker() {
         return switch (CABI.current()) {
             case Win64 -> Windowsx64Linker.getInstance();
             case SysV -> SysVx64Linker.getInstance();
@@ -395,7 +393,7 @@ public class SharedUtils {
 
         // downcalls get the leading NativeSymbol/SegmentAllocator param as well
         if (!upcall) {
-            closer = collectArguments(closer, insertPos++, reachabilityFenceHandle(NativeSymbol.class));
+            closer = collectArguments(closer, insertPos++, reachabilityFenceHandle(Addressable.class));
             closer = dropArguments(closer, insertPos++, SegmentAllocator.class); // (Throwable, V?, NativeSymbol, SegmentAllocator) -> V/void
         }
 
@@ -420,35 +418,35 @@ public class SharedUtils {
     @ForceInline
     @SuppressWarnings("fallthrough")
     public static void acquire(Scoped[] args) {
-        ResourceScope scope4 = null;
+        MemorySessionImpl scope4 = null;
-        ResourceScope scope3 = null;
+        MemorySessionImpl scope3 = null;
-        ResourceScope scope2 = null;
+        MemorySessionImpl scope2 = null;
-        ResourceScope scope1 = null;
+        MemorySessionImpl scope1 = null;
-        ResourceScope scope0 = null;
+        MemorySessionImpl scope0 = null;
         switch (args.length) {
             default:
                 // slow path, acquire all remaining addressable parameters in isolation
                 for (int i = 5 ; i < args.length ; i++) {
-                    acquire(args[i].scope());
+                    acquire(args[i].sessionImpl());
                 }
             // fast path, acquire only scopes not seen in other parameters
             case 5:
-                scope4 = args[4].scope();
+                scope4 = args[4].sessionImpl();
                 acquire(scope4);
             case 4:
-                scope3 = args[3].scope();
+                scope3 = args[3].sessionImpl();
                 if (scope3 != scope4)
                     acquire(scope3);
             case 3:
-                scope2 = args[2].scope();
+                scope2 = args[2].sessionImpl();
                 if (scope2 != scope3 && scope2 != scope4)
                     acquire(scope2);
             case 2:
-                scope1 = args[1].scope();
+                scope1 = args[1].sessionImpl();
                 if (scope1 != scope2 && scope1 != scope3 && scope1 != scope4)
                     acquire(scope1);
             case 1:
-                scope0 = args[0].scope();
+                scope0 = args[0].sessionImpl();
                 if (scope0 != scope1 && scope0 != scope2 && scope0 != scope3 && scope0 != scope4)
                     acquire(scope0);
             case 0: break;
@@ -458,35 +456,35 @@ public class SharedUtils {
     @ForceInline
     @SuppressWarnings("fallthrough")
     public static void release(Scoped[] args) {
-        ResourceScope scope4 = null;
+        MemorySessionImpl scope4 = null;
-        ResourceScope scope3 = null;
+        MemorySessionImpl scope3 = null;
-        ResourceScope scope2 = null;
+        MemorySessionImpl scope2 = null;
-        ResourceScope scope1 = null;
+        MemorySessionImpl scope1 = null;
-        ResourceScope scope0 = null;
+        MemorySessionImpl scope0 = null;
         switch (args.length) {
             default:
                 // slow path, release all remaining addressable parameters in isolation
                 for (int i = 5 ; i < args.length ; i++) {
-                    release(args[i].scope());
+                    release(args[i].sessionImpl());
                 }
             // fast path, release only scopes not seen in other parameters
             case 5:
-                scope4 = args[4].scope();
+                scope4 = args[4].sessionImpl();
                 release(scope4);
             case 4:
-                scope3 = args[3].scope();
+                scope3 = args[3].sessionImpl();
                 if (scope3 != scope4)
                     release(scope3);
             case 3:
-                scope2 = args[2].scope();
+                scope2 = args[2].sessionImpl();
                 if (scope2 != scope3 && scope2 != scope4)
                     release(scope2);
             case 2:
-                scope1 = args[1].scope();
+                scope1 = args[1].sessionImpl();
                 if (scope1 != scope2 && scope1 != scope3 && scope1 != scope4)
                     release(scope1);
             case 1:
-                scope0 = args[0].scope();
+                scope0 = args[0].sessionImpl();
                 if (scope0 != scope1 && scope0 != scope2 && scope0 != scope3 && scope0 != scope4)
                     release(scope0);
             case 0: break;
@@ -494,13 +492,13 @@ public class SharedUtils {
     }
 
     @ForceInline
-    private static void acquire(ResourceScope scope) {
+    private static void acquire(MemorySessionImpl session) {
-        ((ResourceScopeImpl)scope).acquire0();
+        session.acquire0();
     }
 
     @ForceInline
-    private static void release(ResourceScope scope) {
+    private static void release(MemorySessionImpl session) {
-        ((ResourceScopeImpl)scope).release0();
+        session.release0();
     }
 
     /*
@@ -518,7 +516,7 @@ public class SharedUtils {
         List<UnaryOperator<MethodHandle>> adapters = new ArrayList<>();
         for (int i = 0 ; i < downcallHandle.type().parameterCount() ; i++) {
             Class<?> ptype = downcallHandle.type().parameterType(i);
-            if (ptype == Addressable.class || ptype == NativeSymbol.class) {
+            if (ptype == Addressable.class) {
                 addressableCount++;
             } else {
                 int pos = i;
@@ -531,7 +529,7 @@ public class SharedUtils {
 
             MethodType adapterType = MethodType.methodType(void.class);
             for (int i = 0 ; i < addressableCount ; i++) {
-                adapterType = adapterType.appendParameterTypes(i == 0 ? NativeSymbol.class : Addressable.class);
+                adapterType = adapterType.appendParameterTypes(Addressable.class);
             }
 
             MethodHandle acquireHandle = ACQUIRE_MH.asCollector(Scoped[].class, addressableCount).asType(adapterType);
@@ -558,19 +556,7 @@ public class SharedUtils {
         }
     }
 
-    // lazy init MH_ALLOC and MH_FREE handles
+    public static void checkSymbol(Addressable symbol) {
-    private static class AllocHolder {
-
-        private static final CLinker SYS_LINKER = getSystemLinker();
-
-        static final MethodHandle MH_MALLOC = SYS_LINKER.downcallHandle(CLinker.systemCLinker().lookup("malloc").get(),
-                FunctionDescriptor.of(ADDRESS, JAVA_LONG));
-
-        static final MethodHandle MH_FREE = SYS_LINKER.downcallHandle(CLinker.systemCLinker().lookup("free").get(),
-                FunctionDescriptor.ofVoid(ADDRESS));
-    }
-
-    public static void checkSymbol(NativeSymbol symbol) {
         checkAddressable(symbol, "Symbol is NULL");
     }
 
@@ -584,37 +570,21 @@ public class SharedUtils {
             throw new IllegalArgumentException("Symbol is NULL: " + symbol);
     }
 
-    public static MemoryAddress allocateMemoryInternal(long size) {
+    public static VaList newVaList(Consumer<VaList.Builder> actions, MemorySession session) {
-        try {
-            return (MemoryAddress) AllocHolder.MH_MALLOC.invokeExact(size);
-        } catch (Throwable th) {
-            throw new RuntimeException(th);
-        }
-    }
-
-    public static void freeMemoryInternal(MemoryAddress addr) {
-        try {
-            AllocHolder.MH_FREE.invokeExact((Addressable)addr);
-        } catch (Throwable th) {
-            throw new RuntimeException(th);
-        }
-    }
-
-    public static VaList newVaList(Consumer<VaList.Builder> actions, ResourceScope scope) {
         return switch (CABI.current()) {
-            case Win64 -> Windowsx64Linker.newVaList(actions, scope);
+            case Win64 -> Windowsx64Linker.newVaList(actions, session);
-            case SysV -> SysVx64Linker.newVaList(actions, scope);
+            case SysV -> SysVx64Linker.newVaList(actions, session);
-            case LinuxAArch64 -> LinuxAArch64Linker.newVaList(actions, scope);
+            case LinuxAArch64 -> LinuxAArch64Linker.newVaList(actions, session);
-            case MacOsAArch64 -> MacOsAArch64Linker.newVaList(actions, scope);
+            case MacOsAArch64 -> MacOsAArch64Linker.newVaList(actions, session);
         };
     }
 
-    public static VaList newVaListOfAddress(MemoryAddress ma, ResourceScope scope) {
+    public static VaList newVaListOfAddress(MemoryAddress ma, MemorySession session) {
         return switch (CABI.current()) {
-            case Win64 -> Windowsx64Linker.newVaListOfAddress(ma, scope);
+            case Win64 -> Windowsx64Linker.newVaListOfAddress(ma, session);
-            case SysV -> SysVx64Linker.newVaListOfAddress(ma, scope);
+            case SysV -> SysVx64Linker.newVaListOfAddress(ma, session);
-            case LinuxAArch64 -> LinuxAArch64Linker.newVaListOfAddress(ma, scope);
+            case LinuxAArch64 -> LinuxAArch64Linker.newVaListOfAddress(ma, session);
-            case MacOsAArch64 -> MacOsAArch64Linker.newVaListOfAddress(ma, scope);
+            case MacOsAArch64 -> MacOsAArch64Linker.newVaListOfAddress(ma, session);
         };
     }
 
@@ -702,8 +672,13 @@ public class SharedUtils {
         }
 
         @Override
-        public ResourceScope scope() {
+        public MemorySession session() {
-            return ResourceScope.globalScope();
+            return MemorySessionImpl.GLOBAL;
+        }
+
+        @Override
+        public MemorySessionImpl sessionImpl() {
+            return MemorySessionImpl.GLOBAL;
         }
 
         @Override
@@ -720,21 +695,22 @@ public class SharedUtils {
     static void writeOverSized(MemorySegment ptr, Class<?> type, Object o) {
         // use VH_LONG for integers to zero out the whole register in the process
         if (type == long.class) {
-            ptr.set(JAVA_LONG, 0, (long) o);
+            ptr.set(JAVA_LONG_UNALIGNED, 0, (long) o);
         } else if (type == int.class) {
-            ptr.set(JAVA_LONG, 0, (int) o);
+            ptr.set(JAVA_LONG_UNALIGNED, 0, (int) o);
         } else if (type == short.class) {
-            ptr.set(JAVA_LONG, 0, (short) o);
+            ptr.set(JAVA_LONG_UNALIGNED, 0, (short) o);
         } else if (type == char.class) {
-            ptr.set(JAVA_LONG, 0, (char) o);
+            ptr.set(JAVA_LONG_UNALIGNED, 0, (char) o);
         } else if (type == byte.class) {
-            ptr.set(JAVA_LONG, 0, (byte) o);
+            ptr.set(JAVA_LONG_UNALIGNED, 0, (byte) o);
         } else if (type == float.class) {
-            ptr.set(JAVA_FLOAT, 0, (float) o);
+            ptr.set(JAVA_FLOAT_UNALIGNED, 0, (float) o);
         } else if (type == double.class) {
-            ptr.set(JAVA_DOUBLE, 0, (double) o);
+            ptr.set(JAVA_DOUBLE_UNALIGNED, 0, (double) o);
         } else if (type == boolean.class) {
-            ptr.set(JAVA_BOOLEAN, 0, (boolean) o);
+            boolean b = (boolean)o;
+            ptr.set(JAVA_LONG_UNALIGNED, 0, b ? (long)1 : (long)0);
         } else {
             throw new IllegalArgumentException("Unsupported carrier: " + type);
         }
@@ -742,19 +718,19 @@ public class SharedUtils {
 
     static void write(MemorySegment ptr, Class<?> type, Object o) {
         if (type == long.class) {
-            ptr.set(JAVA_LONG, 0, (long) o);
+            ptr.set(JAVA_LONG_UNALIGNED, 0, (long) o);
         } else if (type == int.class) {
-            ptr.set(JAVA_INT, 0, (int) o);
+            ptr.set(JAVA_INT_UNALIGNED, 0, (int) o);
         } else if (type == short.class) {
-            ptr.set(JAVA_SHORT, 0, (short) o);
+            ptr.set(JAVA_SHORT_UNALIGNED, 0, (short) o);
         } else if (type == char.class) {
-            ptr.set(JAVA_CHAR, 0, (char) o);
+            ptr.set(JAVA_CHAR_UNALIGNED, 0, (char) o);
         } else if (type == byte.class) {
             ptr.set(JAVA_BYTE, 0, (byte) o);
         } else if (type == float.class) {
-            ptr.set(JAVA_FLOAT, 0, (float) o);
+            ptr.set(JAVA_FLOAT_UNALIGNED, 0, (float) o);
         } else if (type == double.class) {
-            ptr.set(JAVA_DOUBLE, 0, (double) o);
+            ptr.set(JAVA_DOUBLE_UNALIGNED, 0, (double) o);
         } else if (type == boolean.class) {
             ptr.set(JAVA_BOOLEAN, 0, (boolean) o);
         } else {
@@ -764,19 +740,19 @@ public class SharedUtils {
 
     static Object read(MemorySegment ptr, Class<?> type) {
         if (type == long.class) {
-            return ptr.get(JAVA_LONG, 0);
+            return ptr.get(JAVA_LONG_UNALIGNED, 0);
         } else if (type == int.class) {
-            return ptr.get(JAVA_INT, 0);
+            return ptr.get(JAVA_INT_UNALIGNED, 0);
         } else if (type == short.class) {
-            return ptr.get(JAVA_SHORT, 0);
+            return ptr.get(JAVA_SHORT_UNALIGNED, 0);
         } else if (type == char.class) {
-            return ptr.get(JAVA_CHAR, 0);
+            return ptr.get(JAVA_CHAR_UNALIGNED, 0);
         } else if (type == byte.class) {
             return ptr.get(JAVA_BYTE, 0);
         } else if (type == float.class) {
-            return ptr.get(JAVA_FLOAT, 0);
+            return ptr.get(JAVA_FLOAT_UNALIGNED, 0);
         } else if (type == double.class) {
-            return ptr.get(JAVA_DOUBLE, 0);
+            return ptr.get(JAVA_DOUBLE_UNALIGNED, 0);
         } else if (type == boolean.class) {
             return ptr.get(JAVA_BOOLEAN, 0);
         } else {
@@ -784,6 +760,14 @@ public class SharedUtils {
         }
     }
 
+    // unaligned constants
+    public final static ValueLayout.OfShort JAVA_SHORT_UNALIGNED = JAVA_SHORT.withBitAlignment(8);
+    public final static ValueLayout.OfChar JAVA_CHAR_UNALIGNED = JAVA_CHAR.withBitAlignment(8);
+    public final static ValueLayout.OfInt JAVA_INT_UNALIGNED = JAVA_INT.withBitAlignment(8);
+    public final static ValueLayout.OfLong JAVA_LONG_UNALIGNED = JAVA_LONG.withBitAlignment(8);
+    public final static ValueLayout.OfFloat JAVA_FLOAT_UNALIGNED = JAVA_FLOAT.withBitAlignment(8);
+    public final static ValueLayout.OfDouble JAVA_DOUBLE_UNALIGNED = JAVA_DOUBLE.withBitAlignment(8);
+
     public static MethodType inferMethodType(FunctionDescriptor descriptor, boolean upcall) {
         MethodType type = MethodType.methodType(descriptor.returnLayout().isPresent() ?
                 carrierFor(descriptor.returnLayout().get(), upcall) : void.class);

src/java.base/share/classes/jdk/internal/foreign/abi/UpcallStubs.java

@@ -24,11 +24,11 @@
  */
 package jdk.internal.foreign.abi;
 
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.MemorySession;
-import jdk.internal.foreign.NativeSymbolImpl;
+
-import jdk.internal.foreign.ResourceScopeImpl;
+import jdk.internal.foreign.MemorySessionImpl;
 
 public class UpcallStubs {
 
@@ -48,13 +48,13 @@ public class UpcallStubs {
         registerNatives();
     }
 
-    static NativeSymbol makeUpcall(long entry, ResourceScope scope) {
+    static MemorySegment makeUpcall(long entry, MemorySession session) {
-        ((ResourceScopeImpl)scope).addOrCleanupIfFail(new ResourceScopeImpl.ResourceList.ResourceCleanup() {
+        MemorySessionImpl.toSessionImpl(session).addOrCleanupIfFail(new MemorySessionImpl.ResourceList.ResourceCleanup() {
             @Override
             public void cleanup() {
                 freeUpcallStub(entry);
             }
         });
-        return new NativeSymbolImpl("upcall:" + Long.toHexString(entry), MemoryAddress.ofLong(entry), scope);
+        return MemorySegment.ofAddress(MemoryAddress.ofLong(entry), 0, session);
     }
 }

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/CallArranger.java

@@ -25,25 +25,24 @@
  */
 package jdk.internal.foreign.abi.aarch64;
 
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.GroupLayout;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
-import jdk.incubator.foreign.ResourceScope;
-import jdk.internal.foreign.Utils;
-import jdk.internal.foreign.abi.CallingSequenceBuilder;
 import jdk.internal.foreign.abi.ABIDescriptor;
 import jdk.internal.foreign.abi.Binding;
 import jdk.internal.foreign.abi.CallingSequence;
-import jdk.internal.foreign.abi.ProgrammableInvoker;
+import jdk.internal.foreign.abi.CallingSequenceBuilder;
 import jdk.internal.foreign.abi.ProgrammableUpcallHandler;
-import jdk.internal.foreign.abi.VMStorage;
 import jdk.internal.foreign.abi.SharedUtils;
+import jdk.internal.foreign.abi.VMStorage;
 import jdk.internal.foreign.abi.aarch64.linux.LinuxAArch64CallArranger;
 import jdk.internal.foreign.abi.aarch64.macos.MacOsAArch64CallArranger;
+import jdk.internal.foreign.Utils;
+import jdk.internal.foreign.abi.ProgrammableInvoker;
 
+import java.lang.foreign.MemorySession;
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodType;
 import java.util.List;
@@ -79,7 +78,7 @@ public abstract class CallArranger {
     // Although the AAPCS64 says r0-7 and v0-7 are all valid return
     // registers, it's not possible to generate a C function that uses
     // r2-7 and v4-7 so they are omitted here.
-    private static final ABIDescriptor C = AArch64Architecture.abiFor(
+    private static final ABIDescriptor C = abiFor(
         new VMStorage[] { r0, r1, r2, r3, r4, r5, r6, r7, INDIRECT_RESULT},
         new VMStorage[] { v0, v1, v2, v3, v4, v5, v6, v7 },
         new VMStorage[] { r0, r1 },
@@ -157,14 +156,14 @@ public abstract class CallArranger {
         return handle;
     }
 
-    public NativeSymbol arrangeUpcall(MethodHandle target, MethodType mt, FunctionDescriptor cDesc, ResourceScope scope) {
+    public MemorySegment arrangeUpcall(MethodHandle target, MethodType mt, FunctionDescriptor cDesc, MemorySession session) {
         Bindings bindings = getBindings(mt, cDesc, true);
 
         if (bindings.isInMemoryReturn) {
             target = SharedUtils.adaptUpcallForIMR(target, true /* drop return, since we don't have bindings for it */);
         }
 
-        return ProgrammableUpcallHandler.make(C, target, bindings.callingSequence,scope);
+        return ProgrammableUpcallHandler.make(C, target, bindings.callingSequence, session);
     }
 
     private static boolean isInMemoryReturn(Optional<MemoryLayout> returnLayout) {
@@ -190,7 +189,7 @@ public abstract class CallArranger {
             stackOffset = Utils.alignUp(stackOffset, alignment);
 
             VMStorage storage =
-                AArch64Architecture.stackStorage((int)(stackOffset / STACK_SLOT_SIZE));
+                stackStorage((int)(stackOffset / STACK_SLOT_SIZE));
             stackOffset += size;
             return storage;
         }

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/TypeClass.java

@@ -25,11 +25,11 @@
  */
 package jdk.internal.foreign.abi.aarch64;
 
-import jdk.incubator.foreign.GroupLayout;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.SequenceLayout;
+import java.lang.foreign.SequenceLayout;
-import jdk.incubator.foreign.ValueLayout;
+import java.lang.foreign.ValueLayout;
 
 public enum TypeClass {
     STRUCT_REGISTER,

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/linux/LinuxAArch64CallArranger.java

@@ -25,7 +25,7 @@
  */
 package jdk.internal.foreign.abi.aarch64.linux;
 
-import jdk.internal.foreign.abi.aarch64.*;
+import jdk.internal.foreign.abi.aarch64.CallArranger;
 
 /**
  * AArch64 CallArranger specialized for Linux ABI.

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/linux/LinuxAArch64Linker.java

@@ -25,13 +25,14 @@
  */
 package jdk.internal.foreign.abi.aarch64.linux;
 
-import jdk.incubator.foreign.CLinker;
+import java.lang.foreign.Linker;
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.VaList;
-import jdk.incubator.foreign.VaList;
+
+import jdk.internal.foreign.SystemLookup;
 import jdk.internal.foreign.abi.SharedUtils;
 import jdk.internal.foreign.abi.aarch64.CallArranger;
 
@@ -39,13 +40,14 @@ import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Consumer;
 
 /**
  * ABI implementation based on ARM document "Procedure Call Standard for
  * the ARM 64-bit Architecture".
  */
-public final class LinuxAArch64Linker implements CLinker {
+public final class LinuxAArch64Linker implements Linker {
     private static LinuxAArch64Linker instance;
 
     static final long ADDRESS_SIZE = 64; // bits
@@ -70,8 +72,8 @@ public final class LinuxAArch64Linker implements CLinker {
     }
 
     @Override
-    public final NativeSymbol upcallStub(MethodHandle target, FunctionDescriptor function, ResourceScope scope) {
+    public final MemorySegment upcallStub(MethodHandle target, FunctionDescriptor function, MemorySession session) {
-        Objects.requireNonNull(scope);
+        Objects.requireNonNull(session);
         Objects.requireNonNull(target);
         Objects.requireNonNull(function);
         SharedUtils.checkExceptions(target);
@@ -79,21 +81,25 @@ public final class LinuxAArch64Linker implements CLinker {
         if (!type.equals(target.type())) {
             throw new IllegalArgumentException("Wrong method handle type: " + target.type());
         }
-        return CallArranger.LINUX.arrangeUpcall(target, target.type(), function, scope);
+        return CallArranger.LINUX.arrangeUpcall(target, target.type(), function, session);
     }
 
-    public static VaList newVaList(Consumer<VaList.Builder> actions, ResourceScope scope) {
+    public static VaList newVaList(Consumer<VaList.Builder> actions, MemorySession session) {
-        LinuxAArch64VaList.Builder builder = LinuxAArch64VaList.builder(scope);
+        LinuxAArch64VaList.Builder builder = LinuxAArch64VaList.builder(session);
         actions.accept(builder);
         return builder.build();
     }
 
-    public static VaList newVaListOfAddress(MemoryAddress ma, ResourceScope scope) {
+    public static VaList newVaListOfAddress(MemoryAddress ma, MemorySession session) {
-        return LinuxAArch64VaList.ofAddress(ma, scope);
+        return LinuxAArch64VaList.ofAddress(ma, session);
     }
 
     public static VaList emptyVaList() {
         return LinuxAArch64VaList.empty();
     }
 
+    @Override
+    public SystemLookup defaultLookup() {
+        return SystemLookup.getInstance();
+    }
 }

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/linux/LinuxAArch64VaList.java

@@ -25,12 +25,12 @@
  */
 package jdk.internal.foreign.abi.aarch64.linux;
 
-import jdk.incubator.foreign.*;
+import java.lang.foreign.*;
-import jdk.internal.foreign.ResourceScopeImpl;
+import jdk.internal.foreign.abi.aarch64.TypeClass;
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.foreign.Scoped;
 import jdk.internal.foreign.Utils;
 import jdk.internal.foreign.abi.SharedUtils;
-import jdk.internal.foreign.abi.aarch64.*;
 import jdk.internal.misc.Unsafe;
 
 import java.lang.invoke.VarHandle;
@@ -40,7 +40,7 @@ import java.util.Objects;
 
 import static jdk.internal.foreign.PlatformLayouts.AArch64;
 
-import static jdk.incubator.foreign.MemoryLayout.PathElement.groupElement;
+import static java.lang.foreign.MemoryLayout.PathElement.groupElement;
 import static jdk.internal.foreign.abi.SharedUtils.SimpleVaArg;
 import static jdk.internal.foreign.abi.SharedUtils.THROWING_ALLOCATOR;
 import static jdk.internal.foreign.abi.aarch64.CallArranger.MAX_REGISTER_ARGUMENTS;
@@ -112,19 +112,19 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
 
     private static LinuxAArch64VaList readFromSegment(MemorySegment segment) {
         MemorySegment gpRegsArea = MemorySegment.ofAddress(grTop(segment).addOffset(-MAX_GP_OFFSET),
-                MAX_GP_OFFSET, segment.scope());
+                MAX_GP_OFFSET, segment.session());
 
         MemorySegment fpRegsArea = MemorySegment.ofAddress(vrTop(segment).addOffset(-MAX_FP_OFFSET),
-                MAX_FP_OFFSET, segment.scope());
+                MAX_FP_OFFSET, segment.session());
         return new LinuxAArch64VaList(segment, gpRegsArea, fpRegsArea);
     }
 
     private static MemoryAddress emptyListAddress() {
         long ptr = U.allocateMemory(LAYOUT.byteSize());
-        ResourceScope scope = ResourceScope.newImplicitScope();
+        MemorySession session = MemorySession.openImplicit();
-        scope.addCloseAction(() -> U.freeMemory(ptr));
+        session.addCloseAction(() -> U.freeMemory(ptr));
         MemorySegment ms = MemorySegment.ofAddress(MemoryAddress.ofLong(ptr),
-                LAYOUT.byteSize(), scope);
+                LAYOUT.byteSize(), session);
         VH_stack.set(ms, MemoryAddress.NULL);
         VH_gr_top.set(ms, MemoryAddress.NULL);
         VH_vr_top.set(ms, MemoryAddress.NULL);
@@ -246,7 +246,7 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
             preAlignStack(layout);
             return switch (typeClass) {
                 case STRUCT_REGISTER, STRUCT_HFA, STRUCT_REFERENCE -> {
-                    MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), scope());
+                    MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), session());
                     MemorySegment seg = allocator.allocate(layout);
                     seg.copyFrom(slice);
                     postAlignStack(layout);
@@ -254,7 +254,7 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
                 }
                 case POINTER, INTEGER, FLOAT -> {
                     VarHandle reader = layout.varHandle();
-                    MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), scope());
+                    MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), session());
                     Object res = reader.get(slice);
                     postAlignStack(layout);
                     yield res;
@@ -296,7 +296,7 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
                         gpRegsArea.asSlice(currentGPOffset()));
                     consumeGPSlots(1);
 
-                    MemorySegment slice = MemorySegment.ofAddress(ptr, layout.byteSize(), scope());
+                    MemorySegment slice = MemorySegment.ofAddress(ptr, layout.byteSize(), session());
                     MemorySegment seg = allocator.allocate(layout);
                     seg.copyFrom(slice);
                     yield seg;
@@ -320,7 +320,7 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
     @Override
     public void skip(MemoryLayout... layouts) {
         Objects.requireNonNull(layouts);
-        ((ResourceScopeImpl)segment.scope()).checkValidStateSlow();
+        MemorySessionImpl.toSessionImpl(session()).checkValidStateSlow();
         for (MemoryLayout layout : layouts) {
             Objects.requireNonNull(layout);
             TypeClass typeClass = TypeClass.classifyLayout(layout);
@@ -337,22 +337,27 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
         }
     }
 
-    static LinuxAArch64VaList.Builder builder(ResourceScope scope) {
+    static LinuxAArch64VaList.Builder builder(MemorySession session) {
-        return new LinuxAArch64VaList.Builder(scope);
+        return new LinuxAArch64VaList.Builder(session);
     }
 
-    public static VaList ofAddress(MemoryAddress ma, ResourceScope scope) {
+    public static VaList ofAddress(MemoryAddress ma, MemorySession session) {
-        return readFromSegment(MemorySegment.ofAddress(ma, LAYOUT.byteSize(), scope));
+        return readFromSegment(MemorySegment.ofAddress(ma, LAYOUT.byteSize(), session));
     }
 
     @Override
-    public ResourceScope scope() {
+    public MemorySession session() {
-        return segment.scope();
+        return segment.session();
+    }
+
+    @Override
+    public MemorySessionImpl sessionImpl() {
+        return MemorySessionImpl.toSessionImpl(session());
     }
 
     @Override
     public VaList copy() {
-        MemorySegment copy = MemorySegment.allocateNative(LAYOUT, segment.scope());
+        MemorySegment copy = MemorySegment.allocateNative(LAYOUT, segment.session());
         copy.copyFrom(segment);
         return new LinuxAArch64VaList(copy, gpRegsArea, fpRegsArea);
     }
@@ -389,7 +394,7 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
     }
 
     public static non-sealed class Builder implements VaList.Builder {
-        private final ResourceScope scope;
+        private final MemorySession session;
         private final MemorySegment gpRegs;
         private final MemorySegment fpRegs;
 
@@ -397,10 +402,10 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
         private long currentFPOffset = 0;
         private final List<SimpleVaArg> stackArgs = new ArrayList<>();
 
-        Builder(ResourceScope scope) {
+        Builder(MemorySession session) {
-            this.scope = scope;
+            this.session = session;
-            this.gpRegs = MemorySegment.allocateNative(LAYOUT_GP_REGS, scope);
+            this.gpRegs = MemorySegment.allocateNative(LAYOUT_GP_REGS, session);
-            this.fpRegs = MemorySegment.allocateNative(LAYOUT_FP_REGS, scope);
+            this.fpRegs = MemorySegment.allocateNative(LAYOUT_FP_REGS, session);
         }
 
         @Override
@@ -493,7 +498,7 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
                 return EMPTY;
             }
 
-            SegmentAllocator allocator = SegmentAllocator.newNativeArena(scope);
+            SegmentAllocator allocator = SegmentAllocator.newNativeArena(session);
             MemorySegment vaListSegment = allocator.allocate(LAYOUT);
             MemoryAddress stackArgsPtr = MemoryAddress.NULL;
             if (!stackArgs.isEmpty()) {
@@ -516,8 +521,8 @@ public non-sealed class LinuxAArch64VaList implements VaList, Scoped {
             VH_gr_offs.set(vaListSegment, -MAX_GP_OFFSET);
             VH_vr_offs.set(vaListSegment, -MAX_FP_OFFSET);
 
-            assert gpRegs.scope().ownerThread() == vaListSegment.scope().ownerThread();
+            assert gpRegs.session().ownerThread() == vaListSegment.session().ownerThread();
-            assert fpRegs.scope().ownerThread() == vaListSegment.scope().ownerThread();
+            assert fpRegs.session().ownerThread() == vaListSegment.session().ownerThread();
             return new LinuxAArch64VaList(vaListSegment, gpRegs, fpRegs);
         }
     }

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/macos/MacOsAArch64CallArranger.java

@@ -25,7 +25,7 @@
  */
 package jdk.internal.foreign.abi.aarch64.macos;
 
-import jdk.internal.foreign.abi.aarch64.*;
+import jdk.internal.foreign.abi.aarch64.CallArranger;
 
 /**
  * AArch64 CallArranger specialized for macOS ABI.

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/macos/MacOsAArch64Linker.java

@@ -25,13 +25,14 @@
  */
 package jdk.internal.foreign.abi.aarch64.macos;
 
-import jdk.incubator.foreign.CLinker;
+import java.lang.foreign.Linker;
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.VaList;
-import jdk.incubator.foreign.VaList;
+
+import jdk.internal.foreign.SystemLookup;
 import jdk.internal.foreign.abi.SharedUtils;
 import jdk.internal.foreign.abi.aarch64.CallArranger;
 
@@ -39,13 +40,14 @@ import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Consumer;
 
 /**
  * ABI implementation for macOS on Apple silicon. Based on AAPCS with
  * changes to va_list and passing arguments on the stack.
  */
-public final class MacOsAArch64Linker implements CLinker {
+public final class MacOsAArch64Linker implements Linker {
     private static MacOsAArch64Linker instance;
 
     static final long ADDRESS_SIZE = 64; // bits
@@ -70,29 +72,33 @@ public final class MacOsAArch64Linker implements CLinker {
     }
 
     @Override
-    public final NativeSymbol upcallStub(MethodHandle target, FunctionDescriptor function, ResourceScope scope) {
+    public final MemorySegment upcallStub(MethodHandle target, FunctionDescriptor function, MemorySession session) {
-        Objects.requireNonNull(scope);
+        Objects.requireNonNull(session);
         Objects.requireNonNull(target);
         Objects.requireNonNull(function);
         MethodType type = SharedUtils.inferMethodType(function, true);
         if (!type.equals(target.type())) {
             throw new IllegalArgumentException("Wrong method handle type: " + target.type());
         }
-        return CallArranger.MACOS.arrangeUpcall(target, target.type(), function, scope);
+        return CallArranger.MACOS.arrangeUpcall(target, target.type(), function, session);
     }
 
-    public static VaList newVaList(Consumer<VaList.Builder> actions, ResourceScope scope) {
+    public static VaList newVaList(Consumer<VaList.Builder> actions, MemorySession session) {
-        MacOsAArch64VaList.Builder builder = MacOsAArch64VaList.builder(scope);
+        MacOsAArch64VaList.Builder builder = MacOsAArch64VaList.builder(session);
         actions.accept(builder);
         return builder.build();
     }
 
-    public static VaList newVaListOfAddress(MemoryAddress ma, ResourceScope scope) {
+    public static VaList newVaListOfAddress(MemoryAddress ma, MemorySession session) {
-        return MacOsAArch64VaList.ofAddress(ma, scope);
+        return MacOsAArch64VaList.ofAddress(ma, session);
     }
 
     public static VaList emptyVaList() {
         return MacOsAArch64VaList.empty();
     }
 
+    @Override
+    public SystemLookup defaultLookup() {
+        return SystemLookup.getInstance();
+    }
 }

src/java.base/share/classes/jdk/internal/foreign/abi/aarch64/macos/MacOsAArch64VaList.java

@@ -25,12 +25,12 @@
  */
 package jdk.internal.foreign.abi.aarch64.macos;
 
-import jdk.incubator.foreign.*;
+import java.lang.foreign.*;
+import jdk.internal.foreign.abi.aarch64.TypeClass;
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.foreign.Scoped;
-import jdk.internal.foreign.ResourceScopeImpl;
 import jdk.internal.foreign.abi.SharedUtils;
 import jdk.internal.foreign.abi.SharedUtils.SimpleVaArg;
-import jdk.internal.foreign.abi.aarch64.*;
 
 import java.lang.invoke.VarHandle;
 import java.util.ArrayList;
@@ -53,11 +53,11 @@ public non-sealed class MacOsAArch64VaList implements VaList, Scoped {
     private static final VaList EMPTY = new SharedUtils.EmptyVaList(MemoryAddress.NULL);
 
     private MemorySegment segment;
-    private final ResourceScope scope;
+    private final MemorySession session;
 
-    private MacOsAArch64VaList(MemorySegment segment, ResourceScope scope) {
+    private MacOsAArch64VaList(MemorySegment segment, MemorySession session) {
         this.segment = segment;
-        this.scope = scope;
+        this.session = session;
     }
 
     public static final VaList empty() {
@@ -102,7 +102,7 @@ public non-sealed class MacOsAArch64VaList implements VaList, Scoped {
             res = switch (typeClass) {
                 case STRUCT_REFERENCE -> {
                     MemoryAddress structAddr = (MemoryAddress) VH_address.get(segment);
-                    MemorySegment struct = MemorySegment.ofAddress(structAddr, layout.byteSize(), scope());
+                    MemorySegment struct = MemorySegment.ofAddress(structAddr, layout.byteSize(), session());
                     MemorySegment seg = allocator.allocate(layout);
                     seg.copyFrom(struct);
                     segment = segment.asSlice(VA_SLOT_SIZE_BYTES);
@@ -127,7 +127,7 @@ public non-sealed class MacOsAArch64VaList implements VaList, Scoped {
     @Override
     public void skip(MemoryLayout... layouts) {
         Objects.requireNonNull(layouts);
-        ((ResourceScopeImpl)scope).checkValidStateSlow();
+        MemorySessionImpl.toSessionImpl(session()).checkValidStateSlow();
 
         for (MemoryLayout layout : layouts) {
             Objects.requireNonNull(layout);
@@ -138,24 +138,29 @@ public non-sealed class MacOsAArch64VaList implements VaList, Scoped {
         }
     }
 
-    static MacOsAArch64VaList ofAddress(MemoryAddress addr, ResourceScope scope) {
+    static MacOsAArch64VaList ofAddress(MemoryAddress addr, MemorySession session) {
-        MemorySegment segment = MemorySegment.ofAddress(addr, Long.MAX_VALUE, scope);
+        MemorySegment segment = MemorySegment.ofAddress(addr, Long.MAX_VALUE, session);
-        return new MacOsAArch64VaList(segment, scope);
+        return new MacOsAArch64VaList(segment, session);
     }
 
-    static Builder builder(ResourceScope scope) {
+    static Builder builder(MemorySession session) {
-        return new Builder(scope);
+        return new Builder(session);
     }
 
     @Override
-    public ResourceScope scope() {
+    public MemorySession session() {
-        return scope;
+        return session;
+    }
+
+    @Override
+    public MemorySessionImpl sessionImpl() {
+        return MemorySessionImpl.toSessionImpl(session());
     }
 
     @Override
     public VaList copy() {
-        ((ResourceScopeImpl)scope).checkValidStateSlow();
+        MemorySessionImpl.toSessionImpl(session()).checkValidStateSlow();
-        return new MacOsAArch64VaList(segment, scope);
+        return new MacOsAArch64VaList(segment, session);
     }
 
     @Override
@@ -165,12 +170,12 @@ public non-sealed class MacOsAArch64VaList implements VaList, Scoped {
 
     public static non-sealed class Builder implements VaList.Builder {
 
-        private final ResourceScope scope;
+        private final MemorySession session;
         private final List<SimpleVaArg> args = new ArrayList<>();
 
-        public Builder(ResourceScope scope) {
+        public Builder(MemorySession session) {
-            ((ResourceScopeImpl)scope).checkValidStateSlow();
+            MemorySessionImpl.toSessionImpl(session).checkValidStateSlow();
-            this.scope = scope;
+            this.session = session;
         }
 
         private Builder arg(Class<?> carrier, MemoryLayout layout, Object value) {
@@ -210,7 +215,7 @@ public non-sealed class MacOsAArch64VaList implements VaList, Scoped {
                 return EMPTY;
             }
 
-            SegmentAllocator allocator = SegmentAllocator.newNativeArena(scope);
+            SegmentAllocator allocator = SegmentAllocator.newNativeArena(session);
 
             // Each argument may occupy up to four slots
             MemorySegment segment = allocator.allocate(VA_SLOT_SIZE_BYTES * args.size() * 4);
@@ -243,7 +248,7 @@ public non-sealed class MacOsAArch64VaList implements VaList, Scoped {
                 }
             }
 
-            return new MacOsAArch64VaList(segment, scope);
+            return new MacOsAArch64VaList(segment, session);
         }
     }
 }

src/java.base/share/classes/jdk/internal/foreign/abi/x64/sysv/CallArranger.java

@@ -25,21 +25,19 @@
  */
 package jdk.internal.foreign.abi.x64.sysv;
 
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.GroupLayout;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
-import jdk.internal.foreign.abi.CallingSequenceBuilder;
 import jdk.internal.foreign.abi.ABIDescriptor;
-import jdk.internal.foreign.abi.Binding;
 import jdk.internal.foreign.abi.CallingSequence;
+import jdk.internal.foreign.abi.CallingSequenceBuilder;
+import jdk.internal.foreign.abi.VMStorage;
+import jdk.internal.foreign.abi.Binding;
 import jdk.internal.foreign.abi.ProgrammableInvoker;
 import jdk.internal.foreign.abi.ProgrammableUpcallHandler;
-import jdk.internal.foreign.abi.VMStorage;
-import jdk.internal.foreign.abi.x64.X86_64Architecture;
 import jdk.internal.foreign.abi.SharedUtils;
 
 import java.lang.invoke.MethodHandle;
@@ -51,8 +49,6 @@ import java.util.Optional;
 import static jdk.internal.foreign.PlatformLayouts.*;
 import static jdk.internal.foreign.abi.Binding.*;
 import static jdk.internal.foreign.abi.x64.X86_64Architecture.*;
-import static jdk.internal.foreign.abi.x64.sysv.SysVx64Linker.MAX_INTEGER_ARGUMENT_REGISTERS;
-import static jdk.internal.foreign.abi.x64.sysv.SysVx64Linker.MAX_VECTOR_ARGUMENT_REGISTERS;
 
 /**
  * For the SysV x64 C ABI specifically, this class uses the ProgrammableInvoker API, namely CallingSequenceBuilder2
@@ -61,7 +57,7 @@ import static jdk.internal.foreign.abi.x64.sysv.SysVx64Linker.MAX_VECTOR_ARGUMEN
  * This includes taking care of synthetic arguments like pointers to return buffers for 'in-memory' returns.
  */
 public class CallArranger {
-    private static final ABIDescriptor CSysV = X86_64Architecture.abiFor(
+    private static final ABIDescriptor CSysV = abiFor(
         new VMStorage[] { rdi, rsi, rdx, rcx, r8, r9, rax },
         new VMStorage[] { xmm0, xmm1, xmm2, xmm3, xmm4, xmm5, xmm6, xmm7 },
         new VMStorage[] { rax, rdx },
@@ -133,14 +129,14 @@ public class CallArranger {
         return handle;
     }
 
-    public static NativeSymbol arrangeUpcall(MethodHandle target, MethodType mt, FunctionDescriptor cDesc, ResourceScope scope) {
+    public static MemorySegment arrangeUpcall(MethodHandle target, MethodType mt, FunctionDescriptor cDesc, MemorySession session) {
         Bindings bindings = getBindings(mt, cDesc, true);
 
         if (bindings.isInMemoryReturn) {
             target = SharedUtils.adaptUpcallForIMR(target, true /* drop return, since we don't have bindings for it */);
         }
 
-        return ProgrammableUpcallHandler.make(CSysV, target, bindings.callingSequence, scope);
+        return ProgrammableUpcallHandler.make(CSysV, target, bindings.callingSequence, session);
     }
 
     private static boolean isInMemoryReturn(Optional<MemoryLayout> returnLayout) {
@@ -163,13 +159,13 @@ public class CallArranger {
 
         private int maxRegisterArguments(int type) {
             return type == StorageClasses.INTEGER ?
-                    MAX_INTEGER_ARGUMENT_REGISTERS :
+                    SysVx64Linker.MAX_INTEGER_ARGUMENT_REGISTERS :
                     SysVx64Linker.MAX_VECTOR_ARGUMENT_REGISTERS;
         }
 
         VMStorage stackAlloc() {
             assert forArguments : "no stack returns";
-            VMStorage storage = X86_64Architecture.stackStorage((int)stackOffset);
+            VMStorage storage = stackStorage((int)stackOffset);
             stackOffset++;
             return storage;
         }
@@ -192,14 +188,14 @@ public class CallArranger {
             }
             long nIntegerReg = typeClass.nIntegerRegs();
 
-            if (this.nIntegerReg + nIntegerReg > MAX_INTEGER_ARGUMENT_REGISTERS) {
+            if (this.nIntegerReg + nIntegerReg > SysVx64Linker.MAX_INTEGER_ARGUMENT_REGISTERS) {
                 //not enough registers - pass on stack
                 return typeClass.classes.stream().map(c -> stackAlloc()).toArray(VMStorage[]::new);
             }
 
             long nVectorReg = typeClass.nVectorRegs();
 
-            if (this.nVectorReg + nVectorReg > MAX_VECTOR_ARGUMENT_REGISTERS) {
+            if (this.nVectorReg + nVectorReg > SysVx64Linker.MAX_VECTOR_ARGUMENT_REGISTERS) {
                 //not enough registers - pass on stack
                 return typeClass.classes.stream().map(c -> stackAlloc()).toArray(VMStorage[]::new);
             }

src/java.base/share/classes/jdk/internal/foreign/abi/x64/sysv/SysVVaList.java

@@ -25,8 +25,9 @@
  */
 package jdk.internal.foreign.abi.x64.sysv;
 
-import jdk.incubator.foreign.*;
+import java.lang.foreign.*;
-import jdk.internal.foreign.ResourceScopeImpl;
+
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.foreign.Scoped;
 import jdk.internal.foreign.Utils;
 import jdk.internal.foreign.abi.SharedUtils;
@@ -39,7 +40,7 @@ import java.util.Objects;
 
 import static jdk.internal.foreign.PlatformLayouts.SysV;
 
-import static jdk.incubator.foreign.MemoryLayout.PathElement.groupElement;
+import static java.lang.foreign.MemoryLayout.PathElement.groupElement;
 import static jdk.internal.foreign.abi.SharedUtils.SimpleVaArg;
 import static jdk.internal.foreign.abi.SharedUtils.THROWING_ALLOCATOR;
 
@@ -125,10 +126,10 @@ public non-sealed class SysVVaList implements VaList, Scoped {
 
     private static MemoryAddress emptyListAddress() {
         long ptr = U.allocateMemory(LAYOUT.byteSize());
-        ResourceScope scope = ResourceScope.newImplicitScope();
+        MemorySession session = MemorySession.openImplicit();
-        scope.addCloseAction(() -> U.freeMemory(ptr));
+        session.addCloseAction(() -> U.freeMemory(ptr));
         MemorySegment base = MemorySegment.ofAddress(MemoryAddress.ofLong(ptr),
-                LAYOUT.byteSize(), scope);
+                LAYOUT.byteSize(), session);
         VH_gp_offset.set(base, MAX_GP_OFFSET);
         VH_fp_offset.set(base, MAX_FP_OFFSET);
         VH_overflow_arg_area.set(base, MemoryAddress.NULL);
@@ -170,7 +171,7 @@ public non-sealed class SysVVaList implements VaList, Scoped {
 
     private static MemorySegment getRegSaveArea(MemorySegment segment) {
         return MemorySegment.ofAddress(((MemoryAddress)VH_reg_save_area.get(segment)),
-                LAYOUT_REG_SAVE_AREA.byteSize(), segment.scope());
+                LAYOUT_REG_SAVE_AREA.byteSize(), segment.session());
     }
 
     private void preAlignStack(MemoryLayout layout) {
@@ -221,7 +222,7 @@ public non-sealed class SysVVaList implements VaList, Scoped {
             preAlignStack(layout);
             return switch (typeClass.kind()) {
                 case STRUCT -> {
-                    MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), scope());
+                    MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), session());
                     MemorySegment seg = allocator.allocate(layout);
                     seg.copyFrom(slice);
                     postAlignStack(layout);
@@ -229,8 +230,8 @@ public non-sealed class SysVVaList implements VaList, Scoped {
                 }
                 case POINTER, INTEGER, FLOAT -> {
                     VarHandle reader = layout.varHandle();
-                    try (ResourceScope localScope = ResourceScope.newConfinedScope()) {
+                    try (MemorySession localSession = MemorySession.openConfined()) {
-                        MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), localScope);
+                        MemorySegment slice = MemorySegment.ofAddress(stackPtr(), layout.byteSize(), localSession);
                         Object res = reader.get(slice);
                         postAlignStack(layout);
                         yield res;
@@ -276,7 +277,7 @@ public non-sealed class SysVVaList implements VaList, Scoped {
     @Override
     public void skip(MemoryLayout... layouts) {
         Objects.requireNonNull(layouts);
-        ((ResourceScopeImpl)segment.scope()).checkValidStateSlow();
+        MemorySessionImpl.toSessionImpl(session()).checkValidStateSlow();
         for (MemoryLayout layout : layouts) {
             Objects.requireNonNull(layout);
             TypeClass typeClass = TypeClass.classifyLayout(layout);
@@ -290,22 +291,27 @@ public non-sealed class SysVVaList implements VaList, Scoped {
         }
     }
 
-    static SysVVaList.Builder builder(ResourceScope scope) {
+    static SysVVaList.Builder builder(MemorySession session) {
-        return new SysVVaList.Builder(scope);
+        return new SysVVaList.Builder(session);
     }
 
-    public static VaList ofAddress(MemoryAddress ma, ResourceScope scope) {
+    public static VaList ofAddress(MemoryAddress ma, MemorySession session) {
-        return readFromSegment(MemorySegment.ofAddress(ma, LAYOUT.byteSize(), scope));
+        return readFromSegment(MemorySegment.ofAddress(ma, LAYOUT.byteSize(), session));
     }
 
     @Override
-    public ResourceScope scope() {
+    public MemorySession session() {
-        return segment.scope();
+        return segment.session();
+    }
+
+    @Override
+    public MemorySessionImpl sessionImpl() {
+        return MemorySessionImpl.toSessionImpl(session());
     }
 
     @Override
     public VaList copy() {
-        MemorySegment copy = MemorySegment.allocateNative(LAYOUT, segment.scope());
+        MemorySegment copy = MemorySegment.allocateNative(LAYOUT, segment.session());
         copy.copyFrom(segment);
         return new SysVVaList(copy, regSaveArea);
     }
@@ -331,15 +337,15 @@ public non-sealed class SysVVaList implements VaList, Scoped {
     }
 
     public static non-sealed class Builder implements VaList.Builder {
-        private final ResourceScope scope;
+        private final MemorySession session;
         private final MemorySegment reg_save_area;
         private long currentGPOffset = 0;
         private long currentFPOffset = FP_OFFSET;
         private final List<SimpleVaArg> stackArgs = new ArrayList<>();
 
-        public Builder(ResourceScope scope) {
+        public Builder(MemorySession session) {
-            this.scope = scope;
+            this.session = session;
-            this.reg_save_area = MemorySegment.allocateNative(LAYOUT_REG_SAVE_AREA, scope);
+            this.reg_save_area = MemorySegment.allocateNative(LAYOUT_REG_SAVE_AREA, session);
         }
 
         @Override
@@ -418,7 +424,7 @@ public non-sealed class SysVVaList implements VaList, Scoped {
                 return EMPTY;
             }
 
-            SegmentAllocator allocator = SegmentAllocator.newNativeArena(scope);
+            SegmentAllocator allocator = SegmentAllocator.newNativeArena(session);
             MemorySegment vaListSegment = allocator.allocate(LAYOUT);
             MemoryAddress stackArgsPtr = MemoryAddress.NULL;
             if (!stackArgs.isEmpty()) {
@@ -443,7 +449,7 @@ public non-sealed class SysVVaList implements VaList, Scoped {
             VH_fp_offset.set(vaListSegment, (int) FP_OFFSET);
             VH_overflow_arg_area.set(vaListSegment, stackArgsPtr);
             VH_reg_save_area.set(vaListSegment, reg_save_area.address());
-            assert reg_save_area.scope().ownerThread() == vaListSegment.scope().ownerThread();
+            assert reg_save_area.session().ownerThread() == vaListSegment.session().ownerThread();
             return new SysVVaList(vaListSegment, reg_save_area);
         }
     }

src/java.base/share/classes/jdk/internal/foreign/abi/x64/sysv/SysVx64Linker.java

@@ -25,25 +25,27 @@
 package jdk.internal.foreign.abi.x64.sysv;
 
 
-import jdk.incubator.foreign.CLinker;
+import java.lang.foreign.Linker;
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.VaList;
-import jdk.incubator.foreign.VaList;
+
+import jdk.internal.foreign.SystemLookup;
 import jdk.internal.foreign.abi.SharedUtils;
 
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Consumer;
 
 /**
  * ABI implementation based on System V ABI AMD64 supplement v.0.99.6
  */
-public final class SysVx64Linker implements CLinker {
+public final class SysVx64Linker implements Linker {
     public static final int MAX_INTEGER_ARGUMENT_REGISTERS = 6;
     public static final int MAX_INTEGER_RETURN_REGISTERS = 2;
     public static final int MAX_VECTOR_ARGUMENT_REGISTERS = 8;
@@ -61,8 +63,8 @@ public final class SysVx64Linker implements CLinker {
         return instance;
     }
 
-    public static VaList newVaList(Consumer<VaList.Builder> actions, ResourceScope scope) {
+    public static VaList newVaList(Consumer<VaList.Builder> actions, MemorySession session) {
-        SysVVaList.Builder builder = SysVVaList.builder(scope);
+        SysVVaList.Builder builder = SysVVaList.builder(session);
         actions.accept(builder);
         return builder.build();
     }
@@ -80,8 +82,8 @@ public final class SysVx64Linker implements CLinker {
     }
 
     @Override
-    public final NativeSymbol upcallStub(MethodHandle target, FunctionDescriptor function, ResourceScope scope) {
+    public final MemorySegment upcallStub(MethodHandle target, FunctionDescriptor function, MemorySession session) {
-        Objects.requireNonNull(scope);
+        Objects.requireNonNull(session);
         Objects.requireNonNull(target);
         Objects.requireNonNull(function);
         SharedUtils.checkExceptions(target);
@@ -89,14 +91,19 @@ public final class SysVx64Linker implements CLinker {
         if (!type.equals(target.type())) {
             throw new IllegalArgumentException("Wrong method handle type: " + target.type());
         }
-        return CallArranger.arrangeUpcall(target, target.type(), function, scope);
+        return CallArranger.arrangeUpcall(target, target.type(), function, session);
     }
 
-    public static VaList newVaListOfAddress(MemoryAddress ma, ResourceScope scope) {
+    public static VaList newVaListOfAddress(MemoryAddress ma, MemorySession session) {
-        return SysVVaList.ofAddress(ma, scope);
+        return SysVVaList.ofAddress(ma, session);
     }
 
     public static VaList emptyVaList() {
         return SysVVaList.empty();
     }
+
+    @Override
+    public SystemLookup defaultLookup() {
+        return SystemLookup.getInstance();
+    }
 }

src/java.base/share/classes/jdk/internal/foreign/abi/x64/sysv/TypeClass.java

@@ -24,11 +24,11 @@
  */
 package jdk.internal.foreign.abi.x64.sysv;
 
-import jdk.incubator.foreign.GroupLayout;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.SequenceLayout;
+import java.lang.foreign.SequenceLayout;
-import jdk.incubator.foreign.ValueLayout;
+import java.lang.foreign.ValueLayout;
 import jdk.internal.foreign.Utils;
 
 import java.util.ArrayList;
@@ -214,7 +214,7 @@ class TypeClass {
         } else if (l instanceof SequenceLayout) {
             SequenceLayout seq = (SequenceLayout)l;
             MemoryLayout elem = seq.elementLayout();
-            for (long i = 0 ; i < seq.elementCount().getAsLong() ; i++) {
+            for (long i = 0 ; i < seq.elementCount() ; i++) {
                 groupByEightBytes(elem, offset, groups);
                 offset += elem.byteSize();
             }

src/java.base/share/classes/jdk/internal/foreign/abi/x64/windows/CallArranger.java

@@ -24,13 +24,12 @@
  */
 package jdk.internal.foreign.abi.x64.windows;
 
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.GroupLayout;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
 import jdk.internal.foreign.Utils;
 import jdk.internal.foreign.abi.CallingSequenceBuilder;
 import jdk.internal.foreign.abi.ABIDescriptor;
@@ -133,14 +132,14 @@ public class CallArranger {
         return handle;
     }
 
-    public static NativeSymbol arrangeUpcall(MethodHandle target, MethodType mt, FunctionDescriptor cDesc, ResourceScope scope) {
+    public static MemorySegment arrangeUpcall(MethodHandle target, MethodType mt, FunctionDescriptor cDesc, MemorySession session) {
         Bindings bindings = getBindings(mt, cDesc, true);
 
         if (bindings.isInMemoryReturn) {
             target = SharedUtils.adaptUpcallForIMR(target, false /* need the return value as well */);
         }
 
-        return ProgrammableUpcallHandler.make(CWindows, target, bindings.callingSequence, scope);
+        return ProgrammableUpcallHandler.make(CWindows, target, bindings.callingSequence, session);
     }
 
     private static boolean isInMemoryReturn(Optional<MemoryLayout> returnLayout) {

src/java.base/share/classes/jdk/internal/foreign/abi/x64/windows/TypeClass.java

@@ -24,10 +24,10 @@
  */
 package jdk.internal.foreign.abi.x64.windows;
 
-import jdk.incubator.foreign.GroupLayout;
+import java.lang.foreign.GroupLayout;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemoryLayout;
+import java.lang.foreign.MemoryLayout;
-import jdk.incubator.foreign.ValueLayout;
+import java.lang.foreign.ValueLayout;
 
 enum TypeClass {
     STRUCT_REGISTER,

src/java.base/share/classes/jdk/internal/foreign/abi/x64/windows/WinVaList.java

@@ -25,9 +25,10 @@
  */
 package jdk.internal.foreign.abi.x64.windows;
 
-import jdk.incubator.foreign.*;
+import java.lang.foreign.*;
+
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.foreign.Scoped;
-import jdk.internal.foreign.ResourceScopeImpl;
 import jdk.internal.foreign.abi.SharedUtils;
 import jdk.internal.foreign.abi.SharedUtils.SimpleVaArg;
 
@@ -63,11 +64,11 @@ public non-sealed class WinVaList implements VaList, Scoped {
     private static final VaList EMPTY = new SharedUtils.EmptyVaList(MemoryAddress.NULL);
 
     private MemorySegment segment;
-    private final ResourceScope scope;
+    private final MemorySession session;
 
-    private WinVaList(MemorySegment segment, ResourceScope scope) {
+    private WinVaList(MemorySegment segment, MemorySession session) {
         this.segment = segment;
-        this.scope = scope;
+        this.session = session;
     }
 
     public static final VaList empty() {
@@ -112,7 +113,7 @@ public non-sealed class WinVaList implements VaList, Scoped {
             res = switch (typeClass) {
                 case STRUCT_REFERENCE -> {
                     MemoryAddress structAddr = (MemoryAddress) VH_address.get(segment);
-                    MemorySegment struct = MemorySegment.ofAddress(structAddr, layout.byteSize(), scope());
+                    MemorySegment struct = MemorySegment.ofAddress(structAddr, layout.byteSize(), session());
                     MemorySegment seg = allocator.allocate(layout);
                     seg.copyFrom(struct);
                     yield seg;
@@ -132,29 +133,34 @@ public non-sealed class WinVaList implements VaList, Scoped {
     @Override
     public void skip(MemoryLayout... layouts) {
         Objects.requireNonNull(layouts);
-        ((ResourceScopeImpl)scope).checkValidStateSlow();
+        MemorySessionImpl.toSessionImpl(session()).checkValidStateSlow();
         Stream.of(layouts).forEach(Objects::requireNonNull);
         segment = segment.asSlice(layouts.length * VA_SLOT_SIZE_BYTES);
     }
 
-    static WinVaList ofAddress(MemoryAddress addr, ResourceScope scope) {
+    static WinVaList ofAddress(MemoryAddress addr, MemorySession session) {
-        MemorySegment segment = MemorySegment.ofAddress(addr, Long.MAX_VALUE, scope);
+        MemorySegment segment = MemorySegment.ofAddress(addr, Long.MAX_VALUE, session);
-        return new WinVaList(segment, scope);
+        return new WinVaList(segment, session);
     }
 
-    static Builder builder(ResourceScope scope) {
+    static Builder builder(MemorySession session) {
-        return new Builder(scope);
+        return new Builder(session);
     }
 
     @Override
-    public ResourceScope scope() {
+    public MemorySession session() {
-        return scope;
+        return session;
+    }
+
+    @Override
+    public MemorySessionImpl sessionImpl() {
+        return MemorySessionImpl.toSessionImpl(session());
     }
 
     @Override
     public VaList copy() {
-        ((ResourceScopeImpl)scope).checkValidStateSlow();
+        MemorySessionImpl.toSessionImpl(session).checkValidStateSlow();
-        return new WinVaList(segment, scope);
+        return new WinVaList(segment, session);
     }
 
     @Override
@@ -164,12 +170,12 @@ public non-sealed class WinVaList implements VaList, Scoped {
 
     public static non-sealed class Builder implements VaList.Builder {
 
-        private final ResourceScope scope;
+        private final MemorySession session;
         private final List<SimpleVaArg> args = new ArrayList<>();
 
-        public Builder(ResourceScope scope) {
+        public Builder(MemorySession session) {
-            ((ResourceScopeImpl)scope).checkValidStateSlow();
+            MemorySessionImpl.toSessionImpl(session).checkValidStateSlow();
-            this.scope = scope;
+            this.session = session;
         }
 
         private Builder arg(Class<?> carrier, MemoryLayout layout, Object value) {
@@ -208,7 +214,7 @@ public non-sealed class WinVaList implements VaList, Scoped {
             if (args.isEmpty()) {
                 return EMPTY;
             }
-            SegmentAllocator allocator = SegmentAllocator.newNativeArena(scope);
+            SegmentAllocator allocator = SegmentAllocator.newNativeArena(session);
             MemorySegment segment = allocator.allocate(VA_SLOT_SIZE_BYTES * args.size());
             List<MemorySegment> attachedSegments = new ArrayList<>();
             attachedSegments.add(segment);
@@ -236,7 +242,7 @@ public non-sealed class WinVaList implements VaList, Scoped {
                 cursor = cursor.asSlice(VA_SLOT_SIZE_BYTES);
             }
 
-            return new WinVaList(segment, scope);
+            return new WinVaList(segment, session);
         }
     }
 }

src/java.base/share/classes/jdk/internal/foreign/abi/x64/windows/Windowsx64Linker.java

@@ -24,25 +24,27 @@
  */
 package jdk.internal.foreign.abi.x64.windows;
 
-import jdk.incubator.foreign.CLinker;
+import java.lang.foreign.Linker;
-import jdk.incubator.foreign.FunctionDescriptor;
+import java.lang.foreign.FunctionDescriptor;
-import jdk.incubator.foreign.MemoryAddress;
+import java.lang.foreign.MemoryAddress;
-import jdk.incubator.foreign.MemorySegment;
+import java.lang.foreign.MemorySegment;
-import jdk.incubator.foreign.NativeSymbol;
+import java.lang.foreign.MemorySession;
-import jdk.incubator.foreign.ResourceScope;
+import java.lang.foreign.VaList;
-import jdk.incubator.foreign.VaList;
+
+import jdk.internal.foreign.SystemLookup;
 import jdk.internal.foreign.abi.SharedUtils;
 
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Consumer;
 
 /**
  * ABI implementation based on Windows ABI AMD64 supplement v.0.99.6
  */
-public final class Windowsx64Linker implements CLinker {
+public final class Windowsx64Linker implements Linker {
 
     public static final int MAX_INTEGER_ARGUMENT_REGISTERS = 4;
     public static final int MAX_INTEGER_RETURN_REGISTERS = 1;
@@ -62,8 +64,8 @@ public final class Windowsx64Linker implements CLinker {
         return instance;
     }
 
-    public static VaList newVaList(Consumer<VaList.Builder> actions, ResourceScope scope) {
+    public static VaList newVaList(Consumer<VaList.Builder> actions, MemorySession session) {
-        WinVaList.Builder builder = WinVaList.builder(scope);
+        WinVaList.Builder builder = WinVaList.builder(session);
         actions.accept(builder);
         return builder.build();
     }
@@ -81,8 +83,8 @@ public final class Windowsx64Linker implements CLinker {
     }
 
     @Override
-    public final NativeSymbol upcallStub(MethodHandle target, FunctionDescriptor function, ResourceScope scope) {
+    public final MemorySegment upcallStub(MethodHandle target, FunctionDescriptor function, MemorySession session) {
-        Objects.requireNonNull(scope);
+        Objects.requireNonNull(session);
         Objects.requireNonNull(target);
         Objects.requireNonNull(function);
         SharedUtils.checkExceptions(target);
@@ -90,14 +92,19 @@ public final class Windowsx64Linker implements CLinker {
         if (!type.equals(target.type())) {
             throw new IllegalArgumentException("Wrong method handle type: " + target.type());
         }
-        return CallArranger.arrangeUpcall(target, target.type(), function, scope);
+        return CallArranger.arrangeUpcall(target, target.type(), function, session);
     }
 
-    public static VaList newVaListOfAddress(MemoryAddress ma, ResourceScope scope) {
+    public static VaList newVaListOfAddress(MemoryAddress ma, MemorySession session) {
-        return WinVaList.ofAddress(ma, scope);
+        return WinVaList.ofAddress(ma, session);
     }
 
     public static VaList emptyVaList() {
         return WinVaList.empty();
     }
+
+    @Override
+    public SystemLookup defaultLookup() {
+        return SystemLookup.getInstance();
+    }
 }

src/java.base/share/classes/jdk/internal/javac/PreviewFeature.java

@@ -62,6 +62,7 @@ public @interface PreviewFeature {
     public enum Feature {
         SWITCH_PATTERN_MATCHING,
         VIRTUAL_THREADS,
+        FOREIGN,
         /**
          * A key for testing.
          */

src/java.base/share/classes/jdk/internal/misc/X-ScopedMemoryAccess-bin.java.template

@@ -1,698 +1,698 @@
     @ForceInline
-    public $type$ get$Type$(Scope scope, Object base, long offset) {
+    public $type$ get$Type$(MemorySessionImpl session, Object base, long offset) {
         try {
-            return get$Type$Internal(scope, base, offset);
+            return get$Type$Internal(session, base, offset);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ get$Type$Internal(Scope scope, Object base, long offset) {
+    private $type$ get$Type$Internal(MemorySessionImpl session, Object base, long offset) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.get$Type$(base, offset);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public void put$Type$(Scope scope, Object base, long offset, $type$ value) {
+    public void put$Type$(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            put$Type$Internal(scope, base, offset, value);
+            put$Type$Internal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private void put$Type$Internal(Scope scope, Object base, long offset, $type$ value) {
+    private void put$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             UNSAFE.put$Type$(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
 #if[Unaligned]
     @ForceInline
-    public $type$ get$Type$Unaligned(Scope scope, Object base, long offset, boolean be) {
+    public $type$ get$Type$Unaligned(MemorySessionImpl session, Object base, long offset, boolean be) {
         try {
-            return get$Type$UnalignedInternal(scope, base, offset, be);
+            return get$Type$UnalignedInternal(session, base, offset, be);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ get$Type$UnalignedInternal(Scope scope, Object base, long offset, boolean be) {
+    private $type$ get$Type$UnalignedInternal(MemorySessionImpl session, Object base, long offset, boolean be) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.get$Type$Unaligned(base, offset, be);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public void put$Type$Unaligned(Scope scope, Object base, long offset, $type$ value, boolean be) {
+    public void put$Type$Unaligned(MemorySessionImpl session, Object base, long offset, $type$ value, boolean be) {
         try {
-            put$Type$UnalignedInternal(scope, base, offset, value, be);
+            put$Type$UnalignedInternal(session, base, offset, value, be);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private void put$Type$UnalignedInternal(Scope scope, Object base, long offset, $type$ value, boolean be) {
+    private void put$Type$UnalignedInternal(MemorySessionImpl session, Object base, long offset, $type$ value, boolean be) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             UNSAFE.put$Type$Unaligned(base, offset, value, be);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 #end[Unaligned]
 
     @ForceInline
-    public $type$ get$Type$Volatile(Scope scope, Object base, long offset) {
+    public $type$ get$Type$Volatile(MemorySessionImpl session, Object base, long offset) {
         try {
-            return get$Type$VolatileInternal(scope, base, offset);
+            return get$Type$VolatileInternal(session, base, offset);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ get$Type$VolatileInternal(Scope scope, Object base, long offset) {
+    private $type$ get$Type$VolatileInternal(MemorySessionImpl session, Object base, long offset) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.get$Type$Volatile(base, offset);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public void put$Type$Volatile(Scope scope, Object base, long offset, $type$ value) {
+    public void put$Type$Volatile(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            put$Type$VolatileInternal(scope, base, offset, value);
+            put$Type$VolatileInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private void put$Type$VolatileInternal(Scope scope, Object base, long offset, $type$ value) {
+    private void put$Type$VolatileInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             UNSAFE.put$Type$Volatile(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ get$Type$Acquire(Scope scope, Object base, long offset) {
+    public $type$ get$Type$Acquire(MemorySessionImpl session, Object base, long offset) {
         try {
-            return get$Type$AcquireInternal(scope, base, offset);
+            return get$Type$AcquireInternal(session, base, offset);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ get$Type$AcquireInternal(Scope scope, Object base, long offset) {
+    private $type$ get$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.get$Type$Acquire(base, offset);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public void put$Type$Release(Scope scope, Object base, long offset, $type$ value) {
+    public void put$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            put$Type$ReleaseInternal(scope, base, offset, value);
+            put$Type$ReleaseInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private void put$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ value) {
+    private void put$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             UNSAFE.put$Type$Release(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ get$Type$Opaque(Scope scope, Object base, long offset) {
+    public $type$ get$Type$Opaque(MemorySessionImpl session, Object base, long offset) {
         try {
-            return get$Type$OpaqueInternal(scope, base, offset);
+            return get$Type$OpaqueInternal(session, base, offset);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ get$Type$OpaqueInternal(Scope scope, Object base, long offset) {
+    private $type$ get$Type$OpaqueInternal(MemorySessionImpl session, Object base, long offset) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.get$Type$Opaque(base, offset);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
     @ForceInline
-    public void put$Type$Opaque(Scope scope, Object base, long offset, $type$ value) {
+    public void put$Type$Opaque(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            put$Type$OpaqueInternal(scope, base, offset, value);
+            put$Type$OpaqueInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private void put$Type$OpaqueInternal(Scope scope, Object base, long offset, $type$ value) {
+    private void put$Type$OpaqueInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             UNSAFE.put$Type$Opaque(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 #if[CAS]
     @ForceInline
-    public boolean compareAndSet$Type$(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public boolean compareAndSet$Type$(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return compareAndSet$Type$Internal(scope, base, offset, expected, value);
+            return compareAndSet$Type$Internal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private boolean compareAndSet$Type$Internal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private boolean compareAndSet$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.compareAndSet$Type$(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ compareAndExchange$Type$(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public $type$ compareAndExchange$Type$(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return compareAndExchange$Type$Internal(scope, base, offset, expected, value);
+            return compareAndExchange$Type$Internal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ compareAndExchange$Type$Internal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private $type$ compareAndExchange$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.compareAndExchange$Type$(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ compareAndExchange$Type$Acquire(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public $type$ compareAndExchange$Type$Acquire(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return compareAndExchange$Type$AcquireInternal(scope, base, offset, expected, value);
+            return compareAndExchange$Type$AcquireInternal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ compareAndExchange$Type$AcquireInternal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private $type$ compareAndExchange$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.compareAndExchange$Type$Acquire(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ compareAndExchange$Type$Release(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public $type$ compareAndExchange$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return compareAndExchange$Type$ReleaseInternal(scope, base, offset, expected, value);
+            return compareAndExchange$Type$ReleaseInternal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ compareAndExchange$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private $type$ compareAndExchange$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.compareAndExchange$Type$Release(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public boolean weakCompareAndSet$Type$Plain(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public boolean weakCompareAndSet$Type$Plain(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return weakCompareAndSet$Type$PlainInternal(scope, base, offset, expected, value);
+            return weakCompareAndSet$Type$PlainInternal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private boolean weakCompareAndSet$Type$PlainInternal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private boolean weakCompareAndSet$Type$PlainInternal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.weakCompareAndSet$Type$Plain(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public boolean weakCompareAndSet$Type$(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public boolean weakCompareAndSet$Type$(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return weakCompareAndSet$Type$Internal(scope, base, offset, expected, value);
+            return weakCompareAndSet$Type$Internal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private boolean weakCompareAndSet$Type$Internal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private boolean weakCompareAndSet$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.weakCompareAndSet$Type$(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public boolean weakCompareAndSet$Type$Acquire(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public boolean weakCompareAndSet$Type$Acquire(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return weakCompareAndSet$Type$AcquireInternal(scope, base, offset, expected, value);
+            return weakCompareAndSet$Type$AcquireInternal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private boolean weakCompareAndSet$Type$AcquireInternal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private boolean weakCompareAndSet$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.weakCompareAndSet$Type$Acquire(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public boolean weakCompareAndSet$Type$Release(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    public boolean weakCompareAndSet$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            return weakCompareAndSet$Type$ReleaseInternal(scope, base, offset, expected, value);
+            return weakCompareAndSet$Type$ReleaseInternal(session, base, offset, expected, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private boolean weakCompareAndSet$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ expected, $type$ value) {
+    private boolean weakCompareAndSet$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ expected, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.weakCompareAndSet$Type$Release(base, offset, expected, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndSet$Type$(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndSet$Type$(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndSet$Type$Internal(scope, base, offset, value);
+            return getAndSet$Type$Internal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndSet$Type$Internal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndSet$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndSet$Type$(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndSet$Type$Acquire(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndSet$Type$Acquire(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndSet$Type$AcquireInternal(scope, base, offset, value);
+            return getAndSet$Type$AcquireInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndSet$Type$AcquireInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndSet$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndSet$Type$Acquire(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndSet$Type$Release(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndSet$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndSet$Type$ReleaseInternal(scope, base, offset, value);
+            return getAndSet$Type$ReleaseInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndSet$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndSet$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndSet$Type$Release(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 #end[CAS]
 
 #if[AtomicAdd]
     @ForceInline
-    public $type$ getAndAdd$Type$(Scope scope, Object base, long offset, $type$ delta) {
+    public $type$ getAndAdd$Type$(MemorySessionImpl session, Object base, long offset, $type$ delta) {
         try {
-            return getAndAdd$Type$Internal(scope, base, offset, delta);
+            return getAndAdd$Type$Internal(session, base, offset, delta);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndAdd$Type$Internal(Scope scope, Object base, long offset, $type$ delta) {
+    private $type$ getAndAdd$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ delta) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndAdd$Type$(base, offset, delta);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndAdd$Type$Acquire(Scope scope, Object base, long offset, $type$ delta) {
+    public $type$ getAndAdd$Type$Acquire(MemorySessionImpl session, Object base, long offset, $type$ delta) {
         try {
-            return getAndAdd$Type$AcquireInternal(scope, base, offset, delta);
+            return getAndAdd$Type$AcquireInternal(session, base, offset, delta);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndAdd$Type$AcquireInternal(Scope scope, Object base, long offset, $type$ delta) {
+    private $type$ getAndAdd$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset, $type$ delta) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndAdd$Type$Acquire(base, offset, delta);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndAdd$Type$Release(Scope scope, Object base, long offset, $type$ delta) {
+    public $type$ getAndAdd$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ delta) {
         try {
-            return getAndAdd$Type$ReleaseInternal(scope, base, offset, delta);
+            return getAndAdd$Type$ReleaseInternal(session, base, offset, delta);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndAdd$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ delta) {
+    private $type$ getAndAdd$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ delta) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndAdd$Type$Release(base, offset, delta);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 #end[AtomicAdd]
 
 #if[Bitwise]
     @ForceInline
-    public $type$ getAndBitwiseOr$Type$(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseOr$Type$(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseOr$Type$Internal(scope, base, offset, value);
+            return getAndBitwiseOr$Type$Internal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseOr$Type$Internal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseOr$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseOr$Type$(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseOr$Type$Acquire(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseOr$Type$Acquire(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseOr$Type$AcquireInternal(scope, base, offset, value);
+            return getAndBitwiseOr$Type$AcquireInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseOr$Type$AcquireInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseOr$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseOr$Type$Acquire(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseOr$Type$Release(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseOr$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseOr$Type$ReleaseInternal(scope, base, offset, value);
+            return getAndBitwiseOr$Type$ReleaseInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseOr$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseOr$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseOr$Type$Release(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseAnd$Type$(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseAnd$Type$(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseAnd$Type$Internal(scope, base, offset, value);
+            return getAndBitwiseAnd$Type$Internal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseAnd$Type$Internal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseAnd$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseAnd$Type$(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseAnd$Type$Acquire(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseAnd$Type$Acquire(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseAnd$Type$AcquireInternal(scope, base, offset, value);
+            return getAndBitwiseAnd$Type$AcquireInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseAnd$Type$AcquireInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseAnd$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseAnd$Type$Acquire(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseAnd$Type$Release(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseAnd$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseAnd$Type$ReleaseInternal(scope, base, offset, value);
+            return getAndBitwiseAnd$Type$ReleaseInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseAnd$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseAnd$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseAnd$Type$Release(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseXor$Type$(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseXor$Type$(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseXor$Type$Internal(scope, base, offset, value);
+            return getAndBitwiseXor$Type$Internal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseXor$Type$Internal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseXor$Type$Internal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseXor$Type$(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseXor$Type$Acquire(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseXor$Type$Acquire(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseXor$Type$AcquireInternal(scope, base, offset, value);
+            return getAndBitwiseXor$Type$AcquireInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseXor$Type$AcquireInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseXor$Type$AcquireInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseXor$Type$Acquire(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public $type$ getAndBitwiseXor$Type$Release(Scope scope, Object base, long offset, $type$ value) {
+    public $type$ getAndBitwiseXor$Type$Release(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            return getAndBitwiseXor$Type$ReleaseInternal(scope, base, offset, value);
+            return getAndBitwiseXor$Type$ReleaseInternal(session, base, offset, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private $type$ getAndBitwiseXor$Type$ReleaseInternal(Scope scope, Object base, long offset, $type$ value) {
+    private $type$ getAndBitwiseXor$Type$ReleaseInternal(MemorySessionImpl session, Object base, long offset, $type$ value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return UNSAFE.getAndBitwiseXor$Type$Release(base, offset, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 #end[Bitwise]

src/java.base/share/classes/jdk/internal/misc/X-ScopedMemoryAccess.java.template

@@ -29,6 +29,7 @@ import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
+import java.lang.foreign.MemorySegment;
 import java.lang.ref.Reference;
 import java.io.FileDescriptor;
 import java.nio.Buffer;
@@ -36,7 +37,8 @@ import java.nio.ByteBuffer;
 
 import jdk.internal.access.JavaNioAccess;
 import jdk.internal.access.SharedSecrets;
-import jdk.internal.access.foreign.MemorySegmentProxy;
+import jdk.internal.foreign.AbstractMemorySegmentImpl;
+import jdk.internal.foreign.MemorySessionImpl;
 import jdk.internal.util.ArraysSupport;
 import jdk.internal.vm.annotation.ForceInline;
 import jdk.internal.vm.vector.VectorSupport;
@@ -45,7 +47,7 @@ import jdk.internal.vm.vector.VectorSupport;
 /**
  * This class defines low-level methods to access on-heap and off-heap memory. The methods in this class
  * can be thought of as thin wrappers around methods provided in the {@link Unsafe} class. All the methods in this
- * class, accept one or more {@link Scope} parameter, which is used to validate as to whether access to memory
+ * class accept one or more {@link MemorySessionImpl} parameter, which is used to validate as to whether access to memory
  * can be performed in a safe fashion - more specifically, to ensure that the memory being accessed has not
  * already been released (which would result in a hard VM crash).
  * <p>
@@ -56,17 +58,16 @@ import jdk.internal.vm.vector.VectorSupport;
  * <p>
  * This class provides tools to manage races when multiple threads are accessing and/or releasing the same memory
  * region concurrently. More specifically, when a thread wants to release a memory region, it should call the
- * {@link #closeScope(jdk.internal.misc.ScopedMemoryAccess.Scope)} method provided by this class. This method initiates
+ * {@link MemorySessionImpl#close()} method. This method initiates thread-local handshakes with all the other VM threads,
- * thread-local handshakes with all the other VM threads, which are then stopped one by one. If any thread is found
+ * which are then stopped one by one. If any thread is found accessing a resource associated to the very memory session
- * accessing memory that is associated to the very scope object being closed, that thread execution is asynchronously
+ * being closed, the handshake fails, and the session cannot be closed.
- * interrupted with a {@link Scope.ScopedAccessError}.
  * <p>
  * This synchronization strategy relies on the idea that accessing memory is atomic with respect to checking the
- * validity of the scope associated with that memory region - that is, a thread that wants to perform memory access will be
+ * validity of the session associated with that memory region - that is, a thread that wants to perform memory access will be
- * suspended either <em>before</em> a scope check or <em>after</em> the memory access. To ensure this atomicity,
+ * suspended either <em>before</em> a liveness check or <em>after</em> the memory access. To ensure this atomicity,
  * all methods in this class are marked with the special {@link Scoped} annotation, which is recognized by the VM,
  * and used during the thread-local handshake to detect (and stop) threads performing potentially problematic memory access
- * operations. Additionally, to make sure that the scope object(s) of the memory being accessed is always
+ * operations. Additionally, to make sure that the session object(s) of the memory being accessed is always
  * reachable during an access operation, all the methods in this class add reachability fences around the underlying
  * unsafe access.
  * <p>
@@ -83,11 +84,11 @@ public class ScopedMemoryAccess {
         registerNatives();
     }
 
-    public boolean closeScope(Scope scope) {
+    public boolean closeScope(MemorySessionImpl session) {
-        return closeScope0(scope, Scope.ScopedAccessError.INSTANCE);
+        return closeScope0(session);
     }
 
-    native boolean closeScope0(Scope scope, Scope.ScopedAccessError exception);
+    native boolean closeScope0(MemorySessionImpl session);
 
     private ScopedMemoryAccess() {}
 
@@ -97,28 +98,7 @@ public class ScopedMemoryAccess {
         return theScopedMemoryAccess;
     }
 
-    /**
+    public static final class ScopedAccessError extends Error {
-     * Scope interface used during scoped memory access operations. A scope can be thought of as an object
-     * which embodies the temporal checks associated with a given memory region.
-     */
-    public interface Scope {
-
-        void checkValidState();
-
-        Thread ownerThread();
-
-        void acquire0();
-
-        void release0();
-
-        /**
-         * Error thrown when memory access fails because the memory has already been released.
-         * Note: for performance reasons, this exception is never created by client; instead a shared instance
-         * is thrown (sometimes, this instance can be thrown asynchronously inside VM code). For this reason,
-         * it is important for clients to always catch this exception and throw a regular exception instead
-         * (which contains full stack information).
-         */
-        final class ScopedAccessError extends Error {
         private ScopedAccessError() {
             super("Attempt to access an already released memory resource", null, false, false);
         }
@@ -126,7 +106,6 @@ public class ScopedMemoryAccess {
 
         public static final ScopedAccessError INSTANCE = new ScopedAccessError();
     }
-    }
 
     @Target({ElementType.METHOD, ElementType.CONSTRUCTOR})
     @Retention(RetentionPolicy.RUNTIME)
@@ -135,19 +114,19 @@ public class ScopedMemoryAccess {
     // bulk ops
 
     @ForceInline
-    public void copyMemory(Scope srcScope, Scope dstScope,
+    public void copyMemory(MemorySessionImpl srcScope, MemorySessionImpl dstScope,
                                    Object srcBase, long srcOffset,
                                    Object destBase, long destOffset,
                                    long bytes) {
           try {
               copyMemoryInternal(srcScope, dstScope, srcBase, srcOffset, destBase, destOffset, bytes);
-          } catch (Scope.ScopedAccessError ex) {
+          } catch (ScopedAccessError ex) {
               throw new IllegalStateException("This segment is already closed");
           }
     }
 
     @ForceInline @Scoped
-    private void copyMemoryInternal(Scope srcScope, Scope dstScope,
+    private void copyMemoryInternal(MemorySessionImpl srcScope, MemorySessionImpl dstScope,
                                Object srcBase, long srcOffset,
                                Object destBase, long destOffset,
                                long bytes) {
@@ -166,19 +145,19 @@ public class ScopedMemoryAccess {
     }
 
     @ForceInline
-    public void copySwapMemory(Scope srcScope, Scope dstScope,
+    public void copySwapMemory(MemorySessionImpl srcScope, MemorySessionImpl dstScope,
                                    Object srcBase, long srcOffset,
                                    Object destBase, long destOffset,
                                    long bytes, long elemSize) {
           try {
               copySwapMemoryInternal(srcScope, dstScope, srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
-          } catch (Scope.ScopedAccessError ex) {
+          } catch (ScopedAccessError ex) {
               throw new IllegalStateException("This segment is already closed");
           }
     }
 
     @ForceInline @Scoped
-    private void copySwapMemoryInternal(Scope srcScope, Scope dstScope,
+    private void copySwapMemoryInternal(MemorySessionImpl srcScope, MemorySessionImpl dstScope,
                                Object srcBase, long srcOffset,
                                Object destBase, long destOffset,
                                long bytes, long elemSize) {
@@ -197,41 +176,41 @@ public class ScopedMemoryAccess {
     }
 
     @ForceInline
-    public void setMemory(Scope scope, Object o, long offset, long bytes, byte value) {
+    public void setMemory(MemorySessionImpl session, Object o, long offset, long bytes, byte value) {
         try {
-            setMemoryInternal(scope, o, offset, bytes, value);
+            setMemoryInternal(session, o, offset, bytes, value);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private void setMemoryInternal(Scope scope, Object o, long offset, long bytes, byte value) {
+    private void setMemoryInternal(MemorySessionImpl session, Object o, long offset, long bytes, byte value) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             UNSAFE.setMemory(o, offset, bytes, value);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public int vectorizedMismatch(Scope aScope, Scope bScope,
+    public int vectorizedMismatch(MemorySessionImpl aScope, MemorySessionImpl bScope,
                                              Object a, long aOffset,
                                              Object b, long bOffset,
                                              int length,
                                              int log2ArrayIndexScale) {
         try {
             return vectorizedMismatchInternal(aScope, bScope, a, aOffset, b, bOffset, length, log2ArrayIndexScale);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    private int vectorizedMismatchInternal(Scope aScope, Scope bScope,
+    private int vectorizedMismatchInternal(MemorySessionImpl aScope, MemorySessionImpl bScope,
                                              Object a, long aOffset,
                                              Object b, long bOffset,
                                              int length,
@@ -251,86 +230,86 @@ public class ScopedMemoryAccess {
     }
 
     @ForceInline
-    public boolean isLoaded(Scope scope, long address, boolean isSync, long size) {
+    public boolean isLoaded(MemorySessionImpl session, long address, boolean isSync, long size) {
         try {
-            return isLoadedInternal(scope, address, isSync, size);
+            return isLoadedInternal(session, address, isSync, size);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    public boolean isLoadedInternal(Scope scope, long address, boolean isSync, long size) {
+    public boolean isLoadedInternal(MemorySessionImpl session, long address, boolean isSync, long size) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             return SharedSecrets.getJavaNioAccess().isLoaded(address, isSync, size);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public void load(Scope scope, long address, boolean isSync, long size) {
+    public void load(MemorySessionImpl session, long address, boolean isSync, long size) {
         try {
-            loadInternal(scope, address, isSync, size);
+            loadInternal(session, address, isSync, size);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    public void loadInternal(Scope scope, long address, boolean isSync, long size) {
+    public void loadInternal(MemorySessionImpl session, long address, boolean isSync, long size) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             SharedSecrets.getJavaNioAccess().load(address, isSync, size);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public void unload(Scope scope, long address, boolean isSync, long size) {
+    public void unload(MemorySessionImpl session, long address, boolean isSync, long size) {
         try {
-            unloadInternal(scope, address, isSync, size);
+            unloadInternal(session, address, isSync, size);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    public void unloadInternal(Scope scope, long address, boolean isSync, long size) {
+    public void unloadInternal(MemorySessionImpl session, long address, boolean isSync, long size) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             SharedSecrets.getJavaNioAccess().unload(address, isSync, size);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
     @ForceInline
-    public void force(Scope scope, FileDescriptor fd, long address, boolean isSync, long index, long length) {
+    public void force(MemorySessionImpl session, FileDescriptor fd, long address, boolean isSync, long index, long length) {
         try {
-            forceInternal(scope, fd, address, isSync, index, length);
+            forceInternal(session, fd, address, isSync, index, length);
-        } catch (Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
 
     @ForceInline @Scoped
-    public void forceInternal(Scope scope, FileDescriptor fd, long address, boolean isSync, long index, long length) {
+    public void forceInternal(MemorySessionImpl session, FileDescriptor fd, long address, boolean isSync, long index, long length) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
             SharedSecrets.getJavaNioAccess().force(fd, address, isSync, index, length);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
@@ -363,10 +342,10 @@ public class ScopedMemoryAccess {
         static final JavaNioAccess NIO_ACCESS = SharedSecrets.getJavaNioAccess();
 
         @ForceInline
-        static ScopedMemoryAccess.Scope scope(ByteBuffer bb) {
+        static MemorySessionImpl session(ByteBuffer bb) {
-            MemorySegmentProxy segmentProxy = NIO_ACCESS.bufferSegment(bb);
+            MemorySegment segment = NIO_ACCESS.bufferSegment(bb);
-            return segmentProxy != null ?
+            return segment != null ?
-                    segmentProxy.scope() : null;
+                    ((AbstractMemorySegmentImpl)segment).sessionImpl() : null;
         }
     }
 
@@ -384,12 +363,12 @@ public class ScopedMemoryAccess {
                           VectorSupport.LoadOperation<ByteBuffer, V, S> defaultImpl) {
         try {
             return loadFromByteBufferScoped(
-                    BufferAccess.scope(bb),
+                    BufferAccess.session(bb),
                     vmClass, e, length,
                     bb, offset,
                     s,
                     defaultImpl);
-        } catch (ScopedMemoryAccess.Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
@@ -398,14 +377,14 @@ public class ScopedMemoryAccess {
     @ForceInline
     private static
     <V extends VectorSupport.Vector<E>, E, S extends VectorSupport.VectorSpecies<E>>
-    V loadFromByteBufferScoped(ScopedMemoryAccess.Scope scope,
+    V loadFromByteBufferScoped(MemorySessionImpl session,
                           Class<? extends V> vmClass, Class<E> e, int length,
                           ByteBuffer bb, int offset,
                           S s,
                           VectorSupport.LoadOperation<ByteBuffer, V, S> defaultImpl) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
 
             final byte[] base = (byte[]) BufferAccess.bufferBase(bb);
@@ -415,7 +394,7 @@ public class ScopedMemoryAccess {
                       bb, offset, s,
                       defaultImpl);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
@@ -428,12 +407,12 @@ public class ScopedMemoryAccess {
                                VectorSupport.LoadVectorMaskedOperation<ByteBuffer, V, S, M> defaultImpl) {
         try {
             return loadFromByteBufferMaskedScoped(
-                    BufferAccess.scope(bb),
+                    BufferAccess.session(bb),
                     vmClass, maskClass, e, length,
                     bb, offset, m,
                     s,
                     defaultImpl);
-        } catch (ScopedMemoryAccess.Scope.ScopedAccessError ex) {
+        } catch (ScopedMemoryAccess.ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
@@ -443,14 +422,14 @@ public class ScopedMemoryAccess {
     private static
     <V extends VectorSupport.Vector<E>, E, S extends VectorSupport.VectorSpecies<E>,
      M extends VectorSupport.VectorMask<E>>
-    V loadFromByteBufferMaskedScoped(ScopedMemoryAccess.Scope scope, Class<? extends V> vmClass,
+    V loadFromByteBufferMaskedScoped(MemorySessionImpl session, Class<? extends V> vmClass,
                                      Class<M> maskClass, Class<E> e, int length,
                                      ByteBuffer bb, int offset, M m,
                                      S s,
                                      VectorSupport.LoadVectorMaskedOperation<ByteBuffer, V, S, M> defaultImpl) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
 
             return VectorSupport.loadMasked(vmClass, maskClass, e, length,
@@ -458,7 +437,7 @@ public class ScopedMemoryAccess {
                     bb, offset, s,
                     defaultImpl);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
@@ -471,12 +450,12 @@ public class ScopedMemoryAccess {
                              VectorSupport.StoreVectorOperation<ByteBuffer, V> defaultImpl) {
         try {
             storeIntoByteBufferScoped(
-                    BufferAccess.scope(bb),
+                    BufferAccess.session(bb),
                     vmClass, e, length,
                     v,
                     bb, offset,
                     defaultImpl);
-        } catch (ScopedMemoryAccess.Scope.ScopedAccessError ex) {
+        } catch (ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
@@ -485,14 +464,14 @@ public class ScopedMemoryAccess {
     @ForceInline
     private static
     <V extends VectorSupport.Vector<E>, E>
-    void storeIntoByteBufferScoped(ScopedMemoryAccess.Scope scope,
+    void storeIntoByteBufferScoped(MemorySessionImpl session,
                                    Class<? extends V> vmClass, Class<E> e, int length,
                                    V v,
                                    ByteBuffer bb, int offset,
                                    VectorSupport.StoreVectorOperation<ByteBuffer, V> defaultImpl) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
 
             final byte[] base = (byte[]) BufferAccess.bufferBase(bb);
@@ -503,7 +482,7 @@ public class ScopedMemoryAccess {
                                 bb, offset,
                                 defaultImpl);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 
@@ -516,12 +495,12 @@ public class ScopedMemoryAccess {
                                    VectorSupport.StoreVectorMaskedOperation<ByteBuffer, V, M> defaultImpl) {
         try {
             storeIntoByteBufferMaskedScoped(
-                    BufferAccess.scope(bb),
+                    BufferAccess.session(bb),
                     vmClass, maskClass, e, length,
                     v, m,
                     bb, offset,
                     defaultImpl);
-        } catch (ScopedMemoryAccess.Scope.ScopedAccessError ex) {
+        } catch (ScopedMemoryAccess.ScopedAccessError ex) {
             throw new IllegalStateException("This segment is already closed");
         }
     }
@@ -530,14 +509,14 @@ public class ScopedMemoryAccess {
     @ForceInline
     private static
     <V extends VectorSupport.Vector<E>, E, M extends VectorSupport.VectorMask<E>>
-    void storeIntoByteBufferMaskedScoped(ScopedMemoryAccess.Scope scope,
+    void storeIntoByteBufferMaskedScoped(MemorySessionImpl session,
                                          Class<? extends V> vmClass, Class<M> maskClass,
                                          Class<E> e, int length, V v, M m,
                                          ByteBuffer bb, int offset,
                                          VectorSupport.StoreVectorMaskedOperation<ByteBuffer, V, M> defaultImpl) {
         try {
-            if (scope != null) {
+            if (session != null) {
-                scope.checkValidState();
+                session.checkValidState();
             }
 
             VectorSupport.storeMasked(vmClass, maskClass, e, length,
@@ -546,7 +525,7 @@ public class ScopedMemoryAccess {
                     bb, offset,
                     defaultImpl);
         } finally {
-            Reference.reachabilityFence(scope);
+            Reference.reachabilityFence(session);
         }
     }
 

src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -772,11 +772,23 @@ public final class ModuleBootstrap {
         }
     }
 
+    private static final boolean HAS_ENABLE_NATIVE_ACCESS_FLAG;
+    private static final Set<String> NATIVE_ACCESS_MODULES;
+
+    public static boolean hasEnableNativeAccessFlag() {
+        return HAS_ENABLE_NATIVE_ACCESS_FLAG;
+    }
+
+    static {
+        NATIVE_ACCESS_MODULES = decodeEnableNativeAccess();
+        HAS_ENABLE_NATIVE_ACCESS_FLAG = !NATIVE_ACCESS_MODULES.isEmpty();
+    }
+
     /**
      * Process the --enable-native-access option to grant access to restricted methods to selected modules.
      */
     private static void addEnableNativeAccess(ModuleLayer layer) {
-        for (String name : decodeEnableNativeAccess()) {
+        for (String name : NATIVE_ACCESS_MODULES) {
             if (name.equals("ALL-UNNAMED")) {
                 JLA.addEnableNativeAccessAllUnnamed();
             } else {

src/java.base/share/classes/jdk/internal/reflect/Reflection.java

@@ -30,8 +30,10 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+
 import jdk.internal.access.SharedSecrets;
 import jdk.internal.misc.VM;
+import jdk.internal.module.ModuleBootstrap;
 import jdk.internal.vm.annotation.ForceInline;
 import jdk.internal.vm.annotation.IntrinsicCandidate;
 
@@ -108,10 +110,37 @@ public class Reflection {
     }
 
     @ForceInline
-    public static void ensureNativeAccess(Class<?> currentClass) {
+    public static void ensureNativeAccess(Class<?> currentClass, Class<?> owner, String methodName) {
-        Module module = currentClass.getModule();
+        // if there is no caller class, act as if the call came from unnamed module of system class loader
-        if (!SharedSecrets.getJavaLangAccess().isEnableNativeAccess(module)) {
+        Module module = currentClass != null ?
+                currentClass.getModule() :
+                ClassLoader.getSystemClassLoader().getUnnamedModule();
+        boolean isNativeAccessEnabled = SharedSecrets.getJavaLangAccess().isEnableNativeAccess(module);
+        if (!isNativeAccessEnabled) {
+            synchronized(module) {
+                isNativeAccessEnabled = SharedSecrets.getJavaLangAccess().isEnableNativeAccess(module);
+                if (isNativeAccessEnabled) {
+                    // some other thread got to it, do nothing
+                } else if (ModuleBootstrap.hasEnableNativeAccessFlag()) {
                     throw new IllegalCallerException("Illegal native access from: " + module);
+                } else {
+                    // warn and set flag, so that only one warning is reported per module
+                    String cls = owner.getName();
+                    String mtd = cls + "::" + methodName;
+                    String mod = module.isNamed() ? "module " + module.getName() : "the unnamed module";
+                    String modflag = module.isNamed() ? module.getName() : "ALL-UNNAMED";
+                    System.err.printf("""
+                            WARNING: A restricted method in %s has been called
+                            WARNING: %s has been called by %s
+                            WARNING: Use --enable-native-access=%s to avoid a warning for this module
+                            %n""", cls, mtd, mod, modflag);
+                    if (module.isNamed()) {
+                        SharedSecrets.getJavaLangAccess().addEnableNativeAccess(module);
+                    } else {
+                        SharedSecrets.getJavaLangAccess().addEnableNativeAccessAllUnnamed();
+                    }
+                }
+            }
         }
     }
 

src/java.base/share/classes/module-info.java

@@ -80,6 +80,7 @@ module java.base {
     exports java.lang;
     exports java.lang.annotation;
     exports java.lang.constant;
+    exports java.lang.foreign;
     exports java.lang.invoke;
     exports java.lang.module;
     exports java.lang.ref;
@@ -137,8 +138,7 @@ module java.base {
     exports com.sun.crypto.provider to
         jdk.crypto.cryptoki;
     exports sun.invoke.util to
-        jdk.compiler,
+        jdk.compiler;
-        jdk.incubator.foreign;
     exports com.sun.security.ntlm to
         java.security.sasl;
     exports jdk.internal.javac to
@@ -157,10 +157,7 @@ module java.base {
         jdk.charsets,
         jdk.jartool,
         jdk.jlink,
-        jdk.net,
+        jdk.net;
-        jdk.incubator.foreign;
-    exports jdk.internal.access.foreign to
-        jdk.incubator.foreign;
     exports jdk.internal.event to
         jdk.jfr;
     exports jdk.internal.jimage to
@@ -170,8 +167,7 @@ module java.base {
     exports jdk.internal.loader to
         java.instrument,
         java.logging,
-        java.naming,
+        java.naming;
-        jdk.incubator.foreign;
     exports jdk.internal.jmod to
         jdk.compiler,
         jdk.jlink;
@@ -209,16 +205,14 @@ module java.base {
         jdk.jshell,
         jdk.nio.mapmode,
         jdk.unsupported,
-        jdk.internal.vm.ci,
+        jdk.internal.vm.ci;
-        jdk.incubator.foreign;
     exports jdk.internal.module to
         java.instrument,
         java.management.rmi,
         jdk.jartool,
         jdk.jfr,
         jdk.jlink,
-        jdk.jpackage,
+        jdk.jpackage;
-        jdk.incubator.foreign;
     exports jdk.internal.perf to
         java.management,
         jdk.management.agent,
@@ -227,16 +221,14 @@ module java.base {
         jdk.management,
         jdk.jfr;
     exports jdk.internal.ref to
-        java.desktop,
+        java.desktop;
-        jdk.incubator.foreign;
     exports jdk.internal.reflect to
         java.logging,
         java.sql,
         java.sql.rowset,
         jdk.dynalink,
         jdk.internal.vm.ci,
-        jdk.unsupported,
+        jdk.unsupported;
-        jdk.incubator.foreign;
     exports jdk.internal.vm to
         java.management,
         jdk.internal.jvmstat,
@@ -246,13 +238,10 @@ module java.base {
         java.instrument,
         jdk.internal.vm.ci,
         jdk.incubator.vector,
-        jdk.incubator.foreign,
         jdk.jfr,
         jdk.unsupported;
     exports jdk.internal.vm.vector to
         jdk.incubator.vector;
-    exports jdk.internal.util to
-            jdk.incubator.foreign;
     exports jdk.internal.util.jar to
         jdk.jartool;
     exports jdk.internal.util.xml to
@@ -283,8 +272,7 @@ module java.base {
         java.management,
         jdk.crypto.cryptoki,
         jdk.net,
-        jdk.sctp,
+        jdk.sctp;
-        jdk.incubator.foreign;
     exports sun.nio.cs to
         jdk.charsets;
     exports sun.nio.fs to
@@ -303,8 +291,7 @@ module java.base {
     exports sun.security.action to
         java.desktop,
         java.security.jgss,
-        jdk.crypto.ec,
+        jdk.crypto.ec;
-        jdk.incubator.foreign;
     exports sun.security.internal.interfaces to
         jdk.crypto.cryptoki;
     exports sun.security.internal.spec to
@@ -367,8 +354,6 @@ module java.base {
         java.prefs;
     exports sun.util.resources to
         jdk.localedata;
-    exports jdk.internal.invoke to
-        jdk.incubator.foreign;
 
     // the service types defined by the APIs in this module