8311870: Split CompressedKlassPointers from compressedOops.hpp

Reviewed-by: iklam, rkennke

src/hotspot/cpu/aarch64/jvmciCodeInstaller_aarch64.cpp

@@ -28,6 +28,7 @@
 #include "jvmci/jvmciRuntime.hpp"
 #include "jvmci/jvmciCompilerToVM.hpp"
 #include "jvmci/jvmciJavaClasses.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/jniHandles.hpp"

src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp

@@ -45,6 +45,7 @@
 #include "memory/universe.hpp"
 #include "nativeInst_aarch64.hpp"
 #include "oops/accessDecorators.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/compressedOops.inline.hpp"
 #include "oops/klass.inline.hpp"
 #include "runtime/continuation.hpp"

src/hotspot/cpu/aarch64/macroAssembler_aarch64.hpp

@@ -30,6 +30,7 @@
 #include "code/vmreg.hpp"
 #include "metaprogramming/enableIf.hpp"
 #include "oops/compressedOops.hpp"
+#include "oops/compressedKlass.hpp"
 #include "runtime/vm_version.hpp"
 #include "utilities/powerOfTwo.hpp"
 

src/hotspot/cpu/ppc/macroAssembler_ppc.cpp

@@ -32,6 +32,8 @@
 #include "interpreter/interpreter.hpp"
 #include "memory/resourceArea.hpp"
 #include "nativeInst_ppc.hpp"
+#include "oops/compressedKlass.inline.hpp"
+#include "oops/compressedOops.inline.hpp"
 #include "oops/klass.inline.hpp"
 #include "oops/methodData.hpp"
 #include "prims/methodHandles.hpp"

src/hotspot/cpu/riscv/jvmciCodeInstaller_riscv.cpp

@@ -29,6 +29,7 @@
 #include "jvmci/jvmciRuntime.hpp"
 #include "jvmci/jvmciCompilerToVM.hpp"
 #include "jvmci/jvmciJavaClasses.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/jniHandles.hpp"

src/hotspot/cpu/riscv/macroAssembler_riscv.cpp

@@ -39,6 +39,7 @@
 #include "memory/universe.hpp"
 #include "nativeInst_riscv.hpp"
 #include "oops/accessDecorators.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/compressedOops.inline.hpp"
 #include "oops/klass.inline.hpp"
 #include "oops/oop.hpp"

src/hotspot/cpu/s390/macroAssembler_s390.cpp

@@ -35,6 +35,7 @@
 #include "memory/resourceArea.hpp"
 #include "memory/universe.hpp"
 #include "oops/accessDecorators.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/compressedOops.inline.hpp"
 #include "oops/klass.inline.hpp"
 #include "prims/methodHandles.hpp"

src/hotspot/cpu/x86/jvmciCodeInstaller_x86.cpp

@@ -23,6 +23,7 @@
 
 #include "precompiled.hpp"
 #include "compiler/disassembler.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/javaCalls.hpp"

src/hotspot/cpu/x86/macroAssembler_x86.cpp

@@ -38,6 +38,7 @@
 #include "memory/resourceArea.hpp"
 #include "memory/universe.hpp"
 #include "oops/accessDecorators.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/compressedOops.inline.hpp"
 #include "oops/klass.inline.hpp"
 #include "prims/methodHandles.hpp"

src/hotspot/cpu/x86/relocInfo_x86.cpp

@@ -27,6 +27,7 @@
 #include "code/relocInfo.hpp"
 #include "memory/universe.hpp"
 #include "nativeInst_x86.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/compressedOops.inline.hpp"
 #include "oops/klass.inline.hpp"
 #include "oops/oop.inline.hpp"

src/hotspot/share/cds/archiveBuilder.cpp

@@ -41,6 +41,7 @@
 #include "memory/allStatic.hpp"
 #include "memory/memRegion.hpp"
 #include "memory/resourceArea.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/instanceKlass.hpp"
 #include "oops/objArrayKlass.hpp"
 #include "oops/objArrayOop.inline.hpp"

src/hotspot/share/cds/metaspaceShared.cpp

@@ -61,7 +61,7 @@
 #include "memory/metaspaceClosure.hpp"
 #include "memory/resourceArea.hpp"
 #include "memory/universe.hpp"
-#include "oops/compressedOops.inline.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/instanceMirrorKlass.hpp"
 #include "oops/klass.inline.hpp"
 #include "oops/objArrayOop.hpp"

src/hotspot/share/gc/x/xDebug.gdb

@@ -51,7 +51,7 @@ define zpo
     printf "\t Page: %llu\n", ((uintptr_t)$obj & XAddressOffsetMask) >> XGranuleSizeShift
     x/16gx $obj
     if (UseCompressedClassPointers)
-        set $klass = (Klass*)(void*)((uintptr_t)CompressedKlassPointers::_narrow_klass._base +((uintptr_t)$obj->_metadata->_compressed_klass << CompressedKlassPointers::_narrow_klass._shift))
+        set $klass = (Klass*)(void*)((uintptr_t)CompressedKlassPointers::_base +((uintptr_t)$obj->_metadata->_compressed_klass << CompressedKlassPointers::_shift))
     else
         set $klass = $obj->_metadata->_klass
     end

src/hotspot/share/gc/z/zDebug.gdb

@@ -51,7 +51,7 @@ define zpo
     printf "\t Page: %llu\n", ((uintptr_t)$obj & ZAddressOffsetMask) >> ZGranuleSizeShift
     x/16gx $obj
     if (UseCompressedClassPointers)
-        set $klass = (Klass*)(void*)((uintptr_t)CompressedKlassPointers::_narrow_klass._base +((uintptr_t)$obj->_metadata->_compressed_klass << CompressedKlassPointers::_narrow_klass._shift))
+        set $klass = (Klass*)(void*)((uintptr_t)CompressedKlassPointers::_base +((uintptr_t)$obj->_metadata->_compressed_klass << CompressedKlassPointers::_shift))
     else
         set $klass = $obj->_metadata->_klass
     end

src/hotspot/share/jfr/recorder/checkpoint/types/traceid/jfrTraceIdKlassQueue.cpp

@@ -31,7 +31,7 @@
 #include "jfr/utilities/jfrEpochQueue.inline.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
 #include "memory/metaspace.hpp"
-#include "oops/compressedOops.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "utilities/macros.hpp"
 
 #ifdef VM_LITTLE_ENDIAN

src/hotspot/share/jvmci/jvmciCodeInstaller.cpp

@@ -32,7 +32,7 @@
 #include "jvmci/jvmciCompilerToVM.hpp"
 #include "jvmci/jvmciRuntime.hpp"
 #include "memory/universe.hpp"
-#include "oops/compressedOops.inline.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/klass.inline.hpp"
 #include "prims/jvmtiExport.hpp"
 #include "prims/methodHandles.hpp"

src/hotspot/share/memory/metaspace.cpp

@@ -47,6 +47,7 @@
 #include "memory/metaspaceUtils.hpp"
 #include "memory/resourceArea.hpp"
 #include "memory/universe.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/compressedOops.hpp"
 #include "prims/jvmtiExport.hpp"
 #include "runtime/atomic.hpp"

src/hotspot/share/memory/metaspace/metaspaceCommon.hpp

@@ -26,6 +26,7 @@
 #ifndef SHARE_MEMORY_METASPACE_METASPACECOMMON_HPP
 #define SHARE_MEMORY_METASPACE_METASPACECOMMON_HPP
 
+#include "oops/compressedKlass.hpp"
 #include "runtime/globals.hpp"
 #include "utilities/align.hpp"
 #include "utilities/debug.hpp"

src/hotspot/share/memory/virtualspace.cpp

@@ -26,6 +26,7 @@
 #include "logging/log.hpp"
 #include "memory/resourceArea.hpp"
 #include "memory/virtualspace.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/compressedOops.hpp"
 #include "oops/markWord.hpp"
 #include "oops/oop.inline.hpp"

src/hotspot/share/oops/compressedKlass.cpp

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2019, 2023, 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.
+ *
+ * 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 "precompiled.hpp"
+#include "oops/compressedKlass.hpp"
+#include "runtime/globals.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/ostream.hpp"
+
+address CompressedKlassPointers::_base = nullptr;
+int CompressedKlassPointers::_shift = 0;
+size_t CompressedKlassPointers::_range = 0;
+
+#ifdef _LP64
+
+// Given a klass range [addr, addr+len) and a given encoding scheme, assert that this scheme covers the range, then
+// set this encoding scheme. Used by CDS at runtime to re-instate the scheme used to pre-compute klass ids for
+// archived heap objects.
+void CompressedKlassPointers::initialize_for_given_encoding(address addr, size_t len, address requested_base, int requested_shift) {
+  assert(is_valid_base(requested_base), "Address must be a valid encoding base");
+  address const end = addr + len;
+
+  const int narrow_klasspointer_bits = sizeof(narrowKlass) * 8;
+  const size_t encoding_range_size = nth_bit(narrow_klasspointer_bits + requested_shift);
+  address encoding_range_end = requested_base + encoding_range_size;
+
+  // Note: it would be technically valid for the encoding base to precede the start of the Klass range. But we only call
+  // this function from CDS, and therefore know this to be true.
+  assert(requested_base == addr, "Invalid requested base");
+  assert(encoding_range_end >= end, "Encoding does not cover the full Klass range");
+
+  set_base(requested_base);
+  set_shift(requested_shift);
+  set_range(encoding_range_size);
+}
+
+// Given an address range [addr, addr+len) which the encoding is supposed to
+//  cover, choose base, shift and range.
+//  The address range is the expected range of uncompressed Klass pointers we
+//  will encounter (and the implicit promise that there will be no Klass
+//  structures outside this range).
+void CompressedKlassPointers::initialize(address addr, size_t len) {
+  assert(is_valid_base(addr), "Address must be a valid encoding base");
+  address const end = addr + len;
+
+  address base;
+  int shift;
+  size_t range;
+
+  // Attempt to run with encoding base == zero
+  if (end <= (address)KlassEncodingMetaspaceMax) {
+    base = 0;
+  } else {
+    base = addr;
+  }
+
+  // Highest offset a Klass* can ever have in relation to base.
+  range = end - base;
+
+  // We may not even need a shift if the range fits into 32bit:
+  const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);
+  if (range < UnscaledClassSpaceMax) {
+    shift = 0;
+  } else {
+    shift = LogKlassAlignmentInBytes;
+  }
+
+  set_base(base);
+  set_shift(shift);
+  set_range(range);
+}
+
+// Given an address p, return true if p can be used as an encoding base.
+//  (Some platforms have restrictions of what constitutes a valid base address).
+bool CompressedKlassPointers::is_valid_base(address p) {
+#ifdef AARCH64
+  // Below 32G, base must be aligned to 4G.
+  // Above that point, base must be aligned to 32G
+  if (p < (address)(32 * G)) {
+    return is_aligned(p, 4 * G);
+  }
+  return is_aligned(p, (4 << LogKlassAlignmentInBytes) * G);
+#else
+  return true;
+#endif
+}
+
+void CompressedKlassPointers::print_mode(outputStream* st) {
+  st->print_cr("Narrow klass base: " PTR_FORMAT ", Narrow klass shift: %d, "
+               "Narrow klass range: " SIZE_FORMAT_X, p2i(base()), shift(),
+               range());
+}
+
+void CompressedKlassPointers::set_base(address base) {
+  assert(UseCompressedClassPointers, "no compressed klass ptrs?");
+  _base   = base;
+}
+
+void CompressedKlassPointers::set_shift(int shift)       {
+  assert(shift == 0 || shift == LogKlassAlignmentInBytes, "invalid shift for klass ptrs");
+  _shift   = shift;
+}
+
+void CompressedKlassPointers::set_range(size_t range) {
+  assert(UseCompressedClassPointers, "no compressed klass ptrs?");
+  _range = range;
+}
+
+#endif // _LP64

src/hotspot/share/oops/compressedKlass.hpp

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2019, 2023, 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.
+ *
+ * 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.
+ *
+ */
+
+#ifndef SHARE_OOPS_COMPRESSEDKLASS_HPP
+#define SHARE_OOPS_COMPRESSEDKLASS_HPP
+
+#include "memory/allStatic.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+class outputStream;
+class Klass;
+
+// If compressed klass pointers then use narrowKlass.
+typedef juint  narrowKlass;
+
+const int LogKlassAlignmentInBytes = 3;
+const int KlassAlignmentInBytes    = 1 << LogKlassAlignmentInBytes;
+
+// Maximal size of compressed class space. Above this limit compression is not possible.
+// Also upper bound for placement of zero based class space. (Class space is further limited
+// to be < 3G, see arguments.cpp.)
+const  uint64_t KlassEncodingMetaspaceMax = (uint64_t(max_juint) + 1) << LogKlassAlignmentInBytes;
+
+// For UseCompressedClassPointers.
+class CompressedKlassPointers : public AllStatic {
+  friend class VMStructs;
+
+  static address _base;
+  static int _shift;
+
+  // Together with base, this defines the address range within which Klass
+  //  structures will be located: [base, base+range). While the maximal
+  //  possible encoding range is 4|32G for shift 0|3, if we know beforehand
+  //  the expected range of Klass* pointers will be smaller, a platform
+  //  could use this info to optimize encoding.
+  static size_t _range;
+
+  static void set_base(address base);
+  static void set_range(size_t range);
+  static void set_shift(int shift);
+
+public:
+
+  // Given an address p, return true if p can be used as an encoding base.
+  //  (Some platforms have restrictions of what constitutes a valid base
+  //   address).
+  static bool is_valid_base(address p);
+
+  // Given a klass range [addr, addr+len) and a given encoding scheme, assert that this scheme covers the range, then
+  // set this encoding scheme. Used by CDS at runtime to re-instate the scheme used to pre-compute klass ids for
+  // archived heap objects.
+  static void initialize_for_given_encoding(address addr, size_t len, address requested_base, int requested_shift);
+
+  // Given an address range [addr, addr+len) which the encoding is supposed to
+  //  cover, choose base, shift and range.
+  //  The address range is the expected range of uncompressed Klass pointers we
+  //  will encounter (and the implicit promise that there will be no Klass
+  //  structures outside this range).
+  static void initialize(address addr, size_t len);
+
+  static void     print_mode(outputStream* st);
+
+  static address  base()               { return  _base; }
+  static size_t   range()              { return  _range; }
+  static int      shift()              { return  _shift; }
+
+  static bool is_null(Klass* v)      { return v == nullptr; }
+  static bool is_null(narrowKlass v) { return v == 0; }
+
+  static inline Klass* decode_raw(narrowKlass v, address base, int shift);
+  static inline Klass* decode_raw(narrowKlass v);
+  static inline Klass* decode_not_null(narrowKlass v);
+  static inline Klass* decode_not_null(narrowKlass v, address base, int shift);
+  static inline Klass* decode(narrowKlass v);
+  static inline narrowKlass encode_not_null(Klass* v);
+  static inline narrowKlass encode_not_null(Klass* v, address base, int shift);
+  static inline narrowKlass encode(Klass* v);
+
+};
+
+#endif // SHARE_OOPS_COMPRESSEDKLASS_HPP

src/hotspot/share/oops/compressedKlass.inline.hpp

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2017, 2023, 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.
+ *
+ * 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.
+ *
+ */
+
+#ifndef SHARE_OOPS_COMPRESSEDKLASS_INLINE_HPP
+#define SHARE_OOPS_COMPRESSEDKLASS_INLINE_HPP
+
+#include "oops/compressedKlass.hpp"
+
+#include "memory/universe.hpp"
+#include "oops/oop.hpp"
+#include "utilities/align.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+static inline bool check_alignment(Klass* v) {
+  return (intptr_t)v % KlassAlignmentInBytes == 0;
+}
+
+inline Klass* CompressedKlassPointers::decode_raw(narrowKlass v) {
+  return decode_raw(v, base(), shift());
+}
+
+inline Klass* CompressedKlassPointers::decode_raw(narrowKlass v, address narrow_base, int shift) {
+  return (Klass*)((uintptr_t)narrow_base +((uintptr_t)v << shift));
+}
+
+inline Klass* CompressedKlassPointers::decode_not_null(narrowKlass v) {
+  return decode_not_null(v, base(), shift());
+}
+
+inline Klass* CompressedKlassPointers::decode_not_null(narrowKlass v, address narrow_base, int shift) {
+  assert(!is_null(v), "narrow klass value can never be zero");
+  Klass* result = decode_raw(v, narrow_base, shift);
+  assert(check_alignment(result), "address not aligned: " PTR_FORMAT, p2i(result));
+  return result;
+}
+
+inline Klass* CompressedKlassPointers::decode(narrowKlass v) {
+  return is_null(v) ? nullptr : decode_not_null(v);
+}
+
+inline narrowKlass CompressedKlassPointers::encode_not_null(Klass* v) {
+  return encode_not_null(v, base(), shift());
+}
+
+inline narrowKlass CompressedKlassPointers::encode_not_null(Klass* v, address narrow_base, int shift) {
+  assert(!is_null(v), "klass value can never be zero");
+  assert(check_alignment(v), "Address not aligned");
+  uint64_t pd = (uint64_t)(pointer_delta(v, narrow_base, 1));
+  assert(KlassEncodingMetaspaceMax > pd, "change encoding max if new encoding");
+  uint64_t result = pd >> shift;
+  assert((result & CONST64(0xffffffff00000000)) == 0, "narrow klass pointer overflow");
+  assert(decode_not_null((narrowKlass)result, narrow_base, shift) == v, "reversibility");
+  return (narrowKlass)result;
+}
+
+inline narrowKlass CompressedKlassPointers::encode(Klass* v) {
+  return is_null(v) ? (narrowKlass)0 : encode_not_null(v);
+}
+
+#endif // SHARE_OOPS_COMPRESSEDKLASS_INLINE_HPP

src/hotspot/share/oops/compressedOops.cpp

@@ -177,108 +177,3 @@ void CompressedOops::print_mode(outputStream* st) {
   }
   st->cr();
 }
-
-// For UseCompressedClassPointers.
-NarrowPtrStruct CompressedKlassPointers::_narrow_klass = { nullptr, 0, true };
-
-// CompressedClassSpaceSize set to 1GB, but appear 3GB away from _narrow_ptrs_base during CDS dump.
-// (Todo: we should #ifdef out CompressedKlassPointers for 32bit completely and fix all call sites which
-//  are compiled for 32bit to LP64_ONLY).
-size_t CompressedKlassPointers::_range = 0;
-
-#ifdef _LP64
-
-// Given a klass range [addr, addr+len) and a given encoding scheme, assert that this scheme covers the range, then
-// set this encoding scheme. Used by CDS at runtime to re-instate the scheme used to pre-compute klass ids for
-// archived heap objects.
-void CompressedKlassPointers::initialize_for_given_encoding(address addr, size_t len, address requested_base, int requested_shift) {
-  assert(is_valid_base(requested_base), "Address must be a valid encoding base");
-  address const end = addr + len;
-
-  const int narrow_klasspointer_bits = sizeof(narrowKlass) * 8;
-  const size_t encoding_range_size = nth_bit(narrow_klasspointer_bits + requested_shift);
-  address encoding_range_end = requested_base + encoding_range_size;
-
-  // Note: it would be technically valid for the encoding base to precede the start of the Klass range. But we only call
-  // this function from CDS, and therefore know this to be true.
-  assert(requested_base == addr, "Invalid requested base");
-  assert(encoding_range_end >= end, "Encoding does not cover the full Klass range");
-
-  set_base(requested_base);
-  set_shift(requested_shift);
-  set_range(encoding_range_size);
-}
-
-// Given an address range [addr, addr+len) which the encoding is supposed to
-//  cover, choose base, shift and range.
-//  The address range is the expected range of uncompressed Klass pointers we
-//  will encounter (and the implicit promise that there will be no Klass
-//  structures outside this range).
-void CompressedKlassPointers::initialize(address addr, size_t len) {
-  assert(is_valid_base(addr), "Address must be a valid encoding base");
-  address const end = addr + len;
-
-  address base;
-  int shift;
-  size_t range;
-
-  // Attempt to run with encoding base == zero
-  if (end <= (address)KlassEncodingMetaspaceMax) {
-    base = 0;
-  } else {
-    base = addr;
-  }
-
-  // Highest offset a Klass* can ever have in relation to base.
-  range = end - base;
-
-  // We may not even need a shift if the range fits into 32bit:
-  const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);
-  if (range < UnscaledClassSpaceMax) {
-    shift = 0;
-  } else {
-    shift = LogKlassAlignmentInBytes;
-  }
-
-  set_base(base);
-  set_shift(shift);
-  set_range(range);
-}
-
-// Given an address p, return true if p can be used as an encoding base.
-//  (Some platforms have restrictions of what constitutes a valid base address).
-bool CompressedKlassPointers::is_valid_base(address p) {
-#ifdef AARCH64
-  // Below 32G, base must be aligned to 4G.
-  // Above that point, base must be aligned to 32G
-  if (p < (address)(32 * G)) {
-    return is_aligned(p, 4 * G);
-  }
-  return is_aligned(p, (4 << LogKlassAlignmentInBytes) * G);
-#else
-  return true;
-#endif
-}
-
-void CompressedKlassPointers::print_mode(outputStream* st) {
-  st->print_cr("Narrow klass base: " PTR_FORMAT ", Narrow klass shift: %d, "
-               "Narrow klass range: " SIZE_FORMAT_X, p2i(base()), shift(),
-               range());
-}
-
-void CompressedKlassPointers::set_base(address base) {
-  assert(UseCompressedClassPointers, "no compressed klass ptrs?");
-  _narrow_klass._base   = base;
-}
-
-void CompressedKlassPointers::set_shift(int shift)       {
-  assert(shift == 0 || shift == LogKlassAlignmentInBytes, "invalid shift for klass ptrs");
-  _narrow_klass._shift   = shift;
-}
-
-void CompressedKlassPointers::set_range(size_t range) {
-  assert(UseCompressedClassPointers, "no compressed klass ptrs?");
-  _range = range;
-}
-
-#endif // _LP64

src/hotspot/share/oops/compressedOops.hpp

@@ -40,7 +40,7 @@ struct NarrowPtrStruct {
   address _base;
   // Number of shift bits for encoding/decoding narrow ptrs.
   // 0 if using wide ptrs or zero based unscaled narrow ptrs,
-  // LogMinObjAlignmentInBytes/LogKlassAlignmentInBytes otherwise.
+  // LogMinObjAlignmentInBytes otherwise.
   int     _shift;
   // Generate code with implicit null checks for narrow ptrs.
   bool    _use_implicit_null_checks;
@@ -140,60 +140,4 @@ public:
   static inline narrowOop narrow_oop_cast(T i);
 };
 
-// For UseCompressedClassPointers.
-class CompressedKlassPointers : public AllStatic {
-  friend class VMStructs;
-
-  static NarrowPtrStruct _narrow_klass;
-
-  // Together with base, this defines the address range within which Klass
-  //  structures will be located: [base, base+range). While the maximal
-  //  possible encoding range is 4|32G for shift 0|3, if we know beforehand
-  //  the expected range of Klass* pointers will be smaller, a platform
-  //  could use this info to optimize encoding.
-  static size_t _range;
-
-  static void set_base(address base);
-  static void set_range(size_t range);
-  static void set_shift(int shift);
-
-public:
-
-  // Given an address p, return true if p can be used as an encoding base.
-  //  (Some platforms have restrictions of what constitutes a valid base
-  //   address).
-  static bool is_valid_base(address p);
-
-  // Given a klass range [addr, addr+len) and a given encoding scheme, assert that this scheme covers the range, then
-  // set this encoding scheme. Used by CDS at runtime to re-instate the scheme used to pre-compute klass ids for
-  // archived heap objects.
-  static void initialize_for_given_encoding(address addr, size_t len, address requested_base, int requested_shift);
-
-  // Given an address range [addr, addr+len) which the encoding is supposed to
-  //  cover, choose base, shift and range.
-  //  The address range is the expected range of uncompressed Klass pointers we
-  //  will encounter (and the implicit promise that there will be no Klass
-  //  structures outside this range).
-  static void initialize(address addr, size_t len);
-
-  static void     print_mode(outputStream* st);
-
-  static address  base()               { return  _narrow_klass._base; }
-  static size_t   range()              { return  _range; }
-  static int      shift()              { return  _narrow_klass._shift; }
-
-  static bool is_null(Klass* v)      { return v == nullptr; }
-  static bool is_null(narrowKlass v) { return v == 0; }
-
-  static inline Klass* decode_raw(narrowKlass v, address base, int shift);
-  static inline Klass* decode_raw(narrowKlass v);
-  static inline Klass* decode_not_null(narrowKlass v);
-  static inline Klass* decode_not_null(narrowKlass v, address base, int shift);
-  static inline Klass* decode(narrowKlass v);
-  static inline narrowKlass encode_not_null(Klass* v);
-  static inline narrowKlass encode_not_null(Klass* v, address base, int shift);
-  static inline narrowKlass encode(Klass* v);
-
-};
-
 #endif // SHARE_OOPS_COMPRESSEDOOPS_HPP

src/hotspot/share/oops/compressedOops.inline.hpp

@@ -118,50 +118,4 @@ inline narrowOop CompressedOops::narrow_oop_cast(T i) {
   return static_cast<narrowOop>(narrow_value);
 }
 
-static inline bool check_alignment(Klass* v) {
-  return (intptr_t)v % KlassAlignmentInBytes == 0;
-}
-
-inline Klass* CompressedKlassPointers::decode_raw(narrowKlass v) {
-  return decode_raw(v, base(), shift());
-}
-
-inline Klass* CompressedKlassPointers::decode_raw(narrowKlass v, address narrow_base, int shift) {
-  return (Klass*)((uintptr_t)narrow_base +((uintptr_t)v << shift));
-}
-
-inline Klass* CompressedKlassPointers::decode_not_null(narrowKlass v) {
-  return decode_not_null(v, base(), shift());
-}
-
-inline Klass* CompressedKlassPointers::decode_not_null(narrowKlass v, address narrow_base, int shift) {
-  assert(!is_null(v), "narrow klass value can never be zero");
-  Klass* result = decode_raw(v, narrow_base, shift);
-  assert(check_alignment(result), "address not aligned: " PTR_FORMAT, p2i(result));
-  return result;
-}
-
-inline Klass* CompressedKlassPointers::decode(narrowKlass v) {
-  return is_null(v) ? nullptr : decode_not_null(v);
-}
-
-inline narrowKlass CompressedKlassPointers::encode_not_null(Klass* v) {
-  return encode_not_null(v, base(), shift());
-}
-
-inline narrowKlass CompressedKlassPointers::encode_not_null(Klass* v, address narrow_base, int shift) {
-  assert(!is_null(v), "klass value can never be zero");
-  assert(check_alignment(v), "Address not aligned");
-  uint64_t pd = (uint64_t)(pointer_delta(v, narrow_base, 1));
-  assert(KlassEncodingMetaspaceMax > pd, "change encoding max if new encoding");
-  uint64_t result = pd >> shift;
-  assert((result & CONST64(0xffffffff00000000)) == 0, "narrow klass pointer overflow");
-  assert(decode_not_null((narrowKlass)result, narrow_base, shift) == v, "reversibility");
-  return (narrowKlass)result;
-}
-
-inline narrowKlass CompressedKlassPointers::encode(Klass* v) {
-  return is_null(v) ? (narrowKlass)0 : encode_not_null(v);
-}
-
 #endif // SHARE_OOPS_COMPRESSEDOOPS_INLINE_HPP

src/hotspot/share/oops/oop.cpp

@@ -30,6 +30,7 @@
 #include "memory/resourceArea.hpp"
 #include "memory/universe.hpp"
 #include "oops/access.inline.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/compressedOops.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "oops/verifyOopClosure.hpp"

src/hotspot/share/oops/oop.hpp

@@ -27,6 +27,7 @@
 
 #include "memory/iterator.hpp"
 #include "memory/memRegion.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/accessDecorators.hpp"
 #include "oops/markWord.hpp"
 #include "oops/metadata.hpp"

src/hotspot/share/oops/oop.inline.hpp

@@ -32,7 +32,7 @@
 #include "oops/access.inline.hpp"
 #include "oops/arrayKlass.hpp"
 #include "oops/arrayOop.hpp"
-#include "oops/compressedOops.inline.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/instanceKlass.hpp"
 #include "oops/markWord.hpp"
 #include "oops/oopsHierarchy.hpp"

src/hotspot/share/oops/oopsHierarchy.hpp

@@ -37,9 +37,6 @@
 // Global offset instead of address for an oop within a java object.
 enum class narrowOop : uint32_t { null = 0 };
 
-// If compressed klass pointers then use narrowKlass.
-typedef juint  narrowKlass;
-
 typedef void* OopOrNarrowOopStar;
 
 #ifndef CHECK_UNHANDLED_OOPS

src/hotspot/share/opto/matcher.hpp

@@ -27,6 +27,7 @@
 
 #include "libadt/vectset.hpp"
 #include "memory/resourceArea.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/compressedOops.hpp"
 #include "opto/node.hpp"
 #include "opto/phaseX.hpp"

src/hotspot/share/runtime/arguments.cpp

@@ -41,6 +41,7 @@
 #include "logging/logStream.hpp"
 #include "logging/logTag.hpp"
 #include "memory/allocation.inline.hpp"
+#include "oops/compressedKlass.hpp"
 #include "oops/instanceKlass.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/jvmtiAgentList.hpp"

src/hotspot/share/runtime/os.cpp

@@ -39,7 +39,7 @@
 #include "memory/allocation.inline.hpp"
 #include "memory/resourceArea.hpp"
 #include "memory/universe.hpp"
-#include "oops/compressedOops.inline.hpp"
+#include "oops/compressedKlass.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/jvmtiAgent.hpp"
 #include "prims/jvm_misc.hpp"

src/hotspot/share/runtime/vmStructs.cpp

@@ -379,8 +379,8 @@
   /* CompressedKlassPointers */                                                                                                      \
   /***************************/                                                                                                      \
                                                                                                                                      \
-     static_field(CompressedKlassPointers,     _narrow_klass._base,                           address)                               \
-     static_field(CompressedKlassPointers,     _narrow_klass._shift,                          int)                                   \
+     static_field(CompressedKlassPointers,     _base,                                         address)                               \
+     static_field(CompressedKlassPointers,     _shift,                                        int)                                   \
                                                                                                                                      \
   /**********/                                                                                                                       \
   /* Memory */                                                                                                                       \

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -584,11 +584,6 @@ extern int MinObjAlignmentInBytesMask;
 extern int LogMinObjAlignment;
 extern int LogMinObjAlignmentInBytes;
 
-const int LogKlassAlignmentInBytes = 3;
-const int LogKlassAlignment        = LogKlassAlignmentInBytes - LogHeapWordSize;
-const int KlassAlignmentInBytes    = 1 << LogKlassAlignmentInBytes;
-const int KlassAlignment           = KlassAlignmentInBytes / HeapWordSize;
-
 // Maximal size of heap where unscaled compression can be used. Also upper bound
 // for heap placement: 4GB.
 const  uint64_t UnscaledOopHeapMax = (uint64_t(max_juint) + 1);
@@ -596,11 +591,6 @@ const  uint64_t UnscaledOopHeapMax = (uint64_t(max_juint) + 1);
 // placement for zero based compression algorithm: UnscaledOopHeapMax << LogMinObjAlignmentInBytes.
 extern uint64_t OopEncodingHeapMax;
 
-// Maximal size of compressed class space. Above this limit compression is not possible.
-// Also upper bound for placement of zero based class space. (Class space is further limited
-// to be < 3G, see arguments.cpp.)
-const  uint64_t KlassEncodingMetaspaceMax = (uint64_t(max_juint) + 1) << LogKlassAlignmentInBytes;
-
 // Machine dependent stuff
 
 // The maximum size of the code cache.  Can be overridden by targets.

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/oops/CompressedKlassPointers.java

@@ -58,8 +58,8 @@ public class CompressedKlassPointers {
   private static synchronized void initialize(TypeDataBase db) {
     Type type = db.lookupType("CompressedKlassPointers");
 
-    baseField = type.getAddressField("_narrow_klass._base");
-    shiftField = type.getCIntegerField("_narrow_klass._shift");
+    baseField = type.getAddressField("_base");
+    shiftField = type.getCIntegerField("_shift");
   }
 
   public CompressedKlassPointers() {