8277481: Obsolete seldom used CDS flags

Reviewed-by: iklam, ccheung, dholmes

src/hotspot/share/runtime/arguments.cpp

@@ -1514,7 +1514,7 @@ static void no_shared_spaces(const char* message) {
     vm_exit_during_initialization("Unable to use shared archive", message);
   } else {
     log_info(cds)("Unable to use shared archive: %s", message);
-    FLAG_SET_DEFAULT(UseSharedSpaces, false);
+    UseSharedSpaces = false;
   }
 }
 
@@ -2703,33 +2703,19 @@ jint Arguments::parse_each_vm_init_arg(const JavaVMInitArgs* args, bool* patch_m
           set_mode_flags(_comp);
     // -Xshare:dump
     } else if (match_option(option, "-Xshare:dump")) {
-      if (FLAG_SET_CMDLINE(DumpSharedSpaces, true) != JVMFlag::SUCCESS) {
+      DumpSharedSpaces = true;
-        return JNI_EINVAL;
-      }
     // -Xshare:on
     } else if (match_option(option, "-Xshare:on")) {
-      if (FLAG_SET_CMDLINE(UseSharedSpaces, true) != JVMFlag::SUCCESS) {
+      UseSharedSpaces = true;
-        return JNI_EINVAL;
+      RequireSharedSpaces = true;
-      }
-      if (FLAG_SET_CMDLINE(RequireSharedSpaces, true) != JVMFlag::SUCCESS) {
-        return JNI_EINVAL;
-      }
     // -Xshare:auto || -XX:ArchiveClassesAtExit=<archive file>
     } else if (match_option(option, "-Xshare:auto")) {
-      if (FLAG_SET_CMDLINE(UseSharedSpaces, true) != JVMFlag::SUCCESS) {
+      UseSharedSpaces = true;
-        return JNI_EINVAL;
+      RequireSharedSpaces = false;
-      }
-      if (FLAG_SET_CMDLINE(RequireSharedSpaces, false) != JVMFlag::SUCCESS) {
-        return JNI_EINVAL;
-      }
     // -Xshare:off
     } else if (match_option(option, "-Xshare:off")) {
-      if (FLAG_SET_CMDLINE(UseSharedSpaces, false) != JVMFlag::SUCCESS) {
+      UseSharedSpaces = false;
-        return JNI_EINVAL;
+      RequireSharedSpaces = false;
-      }
-      if (FLAG_SET_CMDLINE(RequireSharedSpaces, false) != JVMFlag::SUCCESS) {
-        return JNI_EINVAL;
-      }
     // -Xverify
     } else if (match_option(option, "-Xverify", &tail)) {
       if (strcmp(tail, ":all") == 0 || strcmp(tail, "") == 0) {
@@ -2983,12 +2969,8 @@ jint Arguments::parse_each_vm_init_arg(const JavaVMInitArgs* args, bool* patch_m
   //   -Xshare:on
   //   -Xlog:class+path=info
   if (PrintSharedArchiveAndExit) {
-    if (FLAG_SET_CMDLINE(UseSharedSpaces, true) != JVMFlag::SUCCESS) {
+    UseSharedSpaces = true;
-      return JNI_EINVAL;
+    RequireSharedSpaces = true;
-    }
-    if (FLAG_SET_CMDLINE(RequireSharedSpaces, true) != JVMFlag::SUCCESS) {
-      return JNI_EINVAL;
-    }
     LogConfiguration::configure_stdout(LogLevel::Info, true, LOG_TAGS(class, path));
   }
 
@@ -3144,11 +3126,11 @@ jint Arguments::finalize_vm_init_args(bool patch_mod_javabase) {
 #if INCLUDE_CDS
   if (DumpSharedSpaces) {
     // Compiler threads may concurrently update the class metadata (such as method entries), so it's
-    // unsafe with DumpSharedSpaces (which modifies the class metadata in place). Let's disable
+    // unsafe with -Xshare:dump (which modifies the class metadata in place). Let's disable
     // compiler just to be safe.
     //
-    // Note: this is not a concern for DynamicDumpSharedSpaces, which makes a copy of the class metadata
+    // Note: this is not a concern for dynamically dumping shared spaces, which makes a copy of the
-    // instead of modifying them in place. The copy is inaccessible to the compiler.
+    // class metadata instead of modifying them in place. The copy is inaccessible to the compiler.
     // TODO: revisit the following for the static archive case.
     set_mode_flags(_int);
   }
@@ -3161,16 +3143,16 @@ jint Arguments::finalize_vm_init_args(bool patch_mod_javabase) {
   }
 
   if (ArchiveClassesAtExit == NULL && !RecordDynamicDumpInfo) {
-    FLAG_SET_DEFAULT(DynamicDumpSharedSpaces, false);
+    DynamicDumpSharedSpaces = false;
   } else {
-    FLAG_SET_DEFAULT(DynamicDumpSharedSpaces, true);
+    DynamicDumpSharedSpaces = true;
   }
 
   if (UseSharedSpaces && patch_mod_javabase) {
     no_shared_spaces("CDS is disabled when " JAVA_BASE_NAME " module is patched.");
   }
   if (UseSharedSpaces && !DumpSharedSpaces && check_unsupported_cds_runtime_properties()) {
-    FLAG_SET_DEFAULT(UseSharedSpaces, false);
+    UseSharedSpaces = false;
   }
 
   if (DumpSharedSpaces || DynamicDumpSharedSpaces) {
@@ -4013,7 +3995,7 @@ jint Arguments::parse(const JavaVMInitArgs* initial_cmd_args) {
   if ((UseSharedSpaces && FLAG_IS_CMDLINE(UseSharedSpaces)) ||
       log_is_enabled(Info, cds)) {
     warning("Shared spaces are not supported in this VM");
-    FLAG_SET_DEFAULT(UseSharedSpaces, false);
+    UseSharedSpaces = false;
     LogConfiguration::configure_stdout(LogLevel::Off, true, LOG_TAGS(cds));
   }
   no_shared_spaces("CDS Disabled");

src/hotspot/share/runtime/globals.hpp

@@ -1805,23 +1805,9 @@ const intx ObjectAlignmentInBytes = 8;
                                                                             \
   /* Shared spaces */                                                       \
                                                                             \
-  product(bool, UseSharedSpaces, true,                                      \
-          "(Deprecated) Use shared spaces for metadata")                    \
-                                                                            \
   product(bool, VerifySharedSpaces, false,                                  \
           "Verify integrity of shared spaces")                              \
                                                                             \
-  product(bool, RequireSharedSpaces, false,                                 \
-          "(Deprecated) Require shared spaces for metadata")                \
-                                                                            \
-  product(bool, DumpSharedSpaces, false,                                    \
-          "(Deprecated) Special mode: JVM reads a class list, loads "       \
-          "classes, builds shared spaces, and dumps the shared spaces to "  \
-          "a file to be used in future JVM runs")                           \
-                                                                            \
-  product(bool, DynamicDumpSharedSpaces, false,                             \
-          "(Deprecated) Dynamic archive")                                   \
-                                                                            \
   product(bool, RecordDynamicDumpInfo, false,                               \
           "Record class info for jcmd VM.cds dynamic_dump")                 \
                                                                             \

src/hotspot/share/utilities/globalDefinitions.cpp

@@ -39,6 +39,14 @@ int LogBitsPerHeapOop  = 0;
 int BytesPerHeapOop    = 0;
 int BitsPerHeapOop     = 0;
 
+// Old CDS options
+bool DumpSharedSpaces;
+bool DynamicDumpSharedSpaces;
+bool RequireSharedSpaces;
+extern "C" {
+JNIEXPORT jboolean UseSharedSpaces = true;
+}
+
 // Object alignment, in units of HeapWords.
 // Defaults are -1 so things will break badly if incorrectly initialized.
 int MinObjAlignment            = -1;

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -508,6 +508,16 @@ const jfloat max_jfloat = jfloat_cast(max_jintFloat);
 
 const int max_method_code_size = 64*K - 1;  // JVM spec, 2nd ed. section 4.8.1 (p.134)
 
+//----------------------------------------------------------------------------------------------------
+// old CDS options
+extern bool DumpSharedSpaces;
+extern bool DynamicDumpSharedSpaces;
+extern bool RequireSharedSpaces;
+extern "C" {
+// Make sure UseSharedSpaces is accessible to the serviceability agent.
+extern JNIEXPORT jboolean UseSharedSpaces;
+}
+
 //----------------------------------------------------------------------------------------------------
 // Object alignment, in units of HeapWords.
 //

src/java.base/share/classes/jdk/internal/misc/CDS.java

@@ -66,7 +66,7 @@ public class CDS {
     }
 
     /**
-      * Is sharing enabled via the UseSharedSpaces flag.
+      * Is sharing enabled.
       */
     public static boolean isSharingEnabled() {
         return isSharingEnabled;
@@ -232,15 +232,11 @@ public class CDS {
 
     private static String[] excludeFlags = {
          "-XX:DumpLoadedClassList=",
-         "-XX:+DumpSharedSpaces",
-         "-XX:+DynamicDumpSharedSpaces",
          "-XX:+RecordDynamicDumpInfo",
          "-Xshare:",
          "-XX:SharedClassListFile=",
          "-XX:SharedArchiveFile=",
-         "-XX:ArchiveClassesAtExit=",
+         "-XX:ArchiveClassesAtExit="};
-         "-XX:+UseSharedSpaces",
-         "-XX:+RequireSharedSpaces"};
     private static boolean containsExcludedFlags(String testStr) {
        for (String e : excludeFlags) {
            if (testStr.contains(e)) {

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/VM.java

@@ -943,9 +943,13 @@ public class VM {
 
   public boolean isSharingEnabled() {
     if (sharingEnabled == null) {
-      Flag flag = getCommandLineFlag("UseSharedSpaces");
+        Address address = VM.getVM().getDebugger().lookup(null, "UseSharedSpaces");
-      sharingEnabled = (flag == null)? Boolean.FALSE :
+        if (address == null && getOS().equals("win32")) {
-          (flag.getBool()? Boolean.TRUE: Boolean.FALSE);
+            // On Win32 symbols are prefixed with the dll name. So look for
+            // UseSharedSpaces as a symbol in jvm.dll.
+            address = VM.getVM().getDebugger().lookup(null, "jvm!UseSharedSpaces");
+        }
+        sharingEnabled = address.getJBooleanAt(0);
     }
     return sharingEnabled.booleanValue();
   }

src/jdk.hotspot.agent/share/native/libsaproc/ps_core_common.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 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
@@ -300,7 +300,7 @@ bool init_classsharing_workaround(struct ps_prochandle* ph) {
       jvm_name = lib->name;
       useSharedSpacesAddr = lookup_symbol(ph, jvm_name, USE_SHARED_SPACES_SYM);
       if (useSharedSpacesAddr == 0) {
-        print_debug("can't lookup 'UseSharedSpaces' flag\n");
+        print_debug("can't lookup 'UseSharedSpaces' symbol\n");
         return false;
       }
 
@@ -308,7 +308,7 @@ bool init_classsharing_workaround(struct ps_prochandle* ph) {
       // using equivalent type jboolean to read the value of
       // UseSharedSpaces which is same as hotspot type "bool".
       if (read_jboolean(ph, useSharedSpacesAddr, &useSharedSpaces) != true) {
-        print_debug("can't read the value of 'UseSharedSpaces' flag\n");
+        print_debug("can't read the value of 'UseSharedSpaces' symbol\n");
         return false;
       }
 

test/hotspot/jtreg/runtime/cds/SharedArchiveFile.java

@@ -45,12 +45,6 @@ public class SharedArchiveFile {
             .setArchiveName("./SharedArchiveFile.jsa");
         CDSTestUtils.createArchiveAndCheck(opts);
 
-        // -XX:+DumpSharedSpaces should behave the same as -Xshare:dump
-        opts = (new CDSOptions())
-            .addPrefix("-XX:+DumpSharedSpaces", "-Xlog:cds")
-            .setArchiveName("./SharedArchiveFile.jsa");
-        CDSTestUtils.createArchiveAndCheck(opts);
-
         opts = (new CDSOptions())
             .setArchiveName("./SharedArchiveFile.jsa");
         CDSTestUtils.run(opts)

test/hotspot/jtreg/runtime/cds/appcds/dynamicArchive/DynamicArchiveTestBase.java

@@ -280,10 +280,10 @@ class DynamicArchiveTestBase {
     }
 
     /**
-     * Return true if the UseSharedSpaces flag has been disabled.
+     * Return true if sharing has been disabled.
      * By default, the VM will be started with -Xshare:auto.
-     * The UseSharedSpaces flag will be disabled by the VM if there's some
+     * Sharing will be disabled by the VM if there's some problem
-     * problem in using the default CDS archive. It could happen under some
+     * in using the default CDS archive. It could happen under some
      * situations such as follows:
      * - the default CDS archive wasn't generated during build time because
      *   the JDK was built via cross-compilation on a different platform;
@@ -294,6 +294,6 @@ class DynamicArchiveTestBase {
      *   enabled when the default CDS archive was built.
      */
     public static boolean isUseSharedSpacesDisabled() {
-        return (WB.getBooleanVMFlag("UseSharedSpaces") == false);
+        return !WB.isSharingEnabled();
     }
 }

test/hotspot/jtreg/runtime/cds/appcds/dynamicArchive/DynamicFlag.java

@@ -1,39 +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.
- *
- * 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.
- *
- */
-
-/*
- * @test
- * @summary The DynamicDumpShareSpaces flag is internal, setting it at the command line should have no effect.
- * @requires vm.cds
- * @library /test/lib /test/hotspot/jtreg/runtime/cds/appcds
- * @compile ../test-classes/Hello.java
- * @run driver DynamicFlag
- */
-
-public class DynamicFlag {
-  public static void main(String[] args) throws Exception {
-      TestCommon.test(JarBuilder.getOrCreateHelloJar(),
-          TestCommon.list("Hello"), "-XX:+DynamicDumpSharedSpaces", "Hello");
-  }
-}

test/hotspot/jtreg/runtime/cds/appcds/jcmd/JCmdTestDumpBase.java

@@ -96,7 +96,7 @@ public abstract class JCmdTestDumpBase {
     }
 
     private static void checkCDSEnabled() throws Exception {
-        boolean cdsEnabled = WhiteBox.getWhiteBox().getBooleanVMFlag("UseSharedSpaces");
+        boolean cdsEnabled = WhiteBox.getWhiteBox().isSharingEnabled();
         if (!cdsEnabled) {
             throw new SkippedException("CDS is not available for this JDK.");
         }

test/hotspot/jtreg/runtime/cds/appcds/jcmd/JCmdTestDynamicDump.java

@@ -81,20 +81,13 @@ public class JCmdTestDynamicDump extends JCmdTestDumpBase {
         test(null, pid, noBoot, EXPECT_PASS, DYNAMIC_MESSAGES);
         app.stopApp();
 
-        // Test dynamic dump with flags -XX:+RecordDynamicDumpInfo -XX:-DynamicDumpSharedSpaces.
+        // Test dynamic dump with flag -XX:+RecordDynamicDumpInfo
-        print2ln(test_count++ + " Test dynamic dump with flags -XX:+RecordDynamicDumpInfo -XX:-DynamicDumpSharedSpaces.");
+        print2ln(test_count++ + " Test dynamic dump with flag -XX:+RecordDynamicDumpInfo.");
-        app = createLingeredApp("-cp", allJars, "-XX:+RecordDynamicDumpInfo", "-XX:-DynamicDumpSharedSpaces");
+        app = createLingeredApp("-cp", allJars, "-XX:+RecordDynamicDumpInfo");
         pid = app.getPid();
         test(null, pid, noBoot, EXPECT_PASS, DYNAMIC_MESSAGES);
         app.stopApp();
 
-        // Test dynamic dump with flags -XX:-DynamicDumpSharedSpaces -XX:+RecordDynamicDumpInfo.
-        print2ln(test_count++ + " Test dynamic dump with flags -XX:-DynamicDumpSharedSpaces -XX:+RecordDynamicDumpInfo.");
-        app = createLingeredApp("-cp", allJars, "-XX:-DynamicDumpSharedSpaces", "-XX:+RecordDynamicDumpInfo");
-        pid = app.getPid();
-        test(null, pid, noBoot,  EXPECT_PASS, DYNAMIC_MESSAGES);
-        app.stopApp();
-
         // Test dynamic with -Xbootclasspath/a:boot.jar
         print2ln(test_count++ + " Test dynamic with -Xbootclasspath/a:boot.jar");
         app = createLingeredApp("-cp", testJar, "-Xbootclasspath/a:" + bootJar, "-XX:+RecordDynamicDumpInfo");

test/hotspot/jtreg/runtime/cds/appcds/jcmd/JCmdTestStaticDump.java

@@ -45,25 +45,19 @@ public class JCmdTestStaticDump extends JCmdTestDumpBase {
                                                "LingeredApp source: shared objects file",
                                                "Hello source: shared objects file"};
 
-    // Those two flags will not create a successful LingeredApp.
+    // This flag will not create a successful LingeredApp.
     private static String[] noDumpFlags  =
-        {"-XX:+DumpSharedSpaces",
+        {"-Xshare:dump"};
-         "-Xshare:dump"};
     // Those flags will be excluded in static dumping,
     // See src/java.base/share/classes/jdk/internal/misc/CDS.java
     private static String[] excludeFlags = {
          "-XX:DumpLoadedClassList=AnyFileName.classlist",
-         // this flag just dump archive, won't run app normally.
-         // "-XX:+DumpSharedSpaces",
-         "-XX:+DynamicDumpSharedSpaces",
          "-XX:+RecordDynamicDumpInfo",
          "-Xshare:on",
          "-Xshare:auto",
          "-XX:SharedClassListFile=non-exist.classlist",
          "-XX:SharedArchiveFile=non-exist.jsa",
-         "-XX:ArchiveClassesAtExit=tmp.jsa",
+         "-XX:ArchiveClassesAtExit=tmp.jsa"};
-         "-XX:+UseSharedSpaces",
-         "-XX:+RequireSharedSpaces"};
 
     // Times to dump cds against same process.
     private static final int ITERATION_TIMES = 2;