JDK-8303069: Memory leak in CompilerOracle::parse_from_line

[dafedafe]

A memory leak has been detected using lsan when running the compiler/blackhole/BlackholeExperimentalUnlockTest.java test.

This happens when parsing the blackhole CompileCommand. There is a check for the -XX:+UnlockExperimentalVMOptions flag being enabled when blackhole is used. If this flag is not set, a warning gets printed and the CompileCommand is not taken.

Unfortunately this happens in register_commands where commands are supposed to be added to a list. In this case we bail out and the option is neither added nor deleted.

jdk/src/hotspot/share/compiler/compilerOracle.cpp

Lines 310 to 313 in f629152

	if (option == CompileCommand::Blackhole && !UnlockExperimentalVMOptions) {
	warning("Blackhole compile option is experimental and must be enabled via -XX:+UnlockExperimentalVMOptions");
	return;
	}

So, this changes deletes the matcher object before returning. This is done in register_commands (the callee) mainly because a couple of other similar checks are also done in this function.

The other option would have been to move the check to the caller (the only one for this case) before register_command:

jdk/src/hotspot/share/compiler/compilerOracle.cpp

Lines 915 to 917 in f629152

	if (option2type(option) == OptionType::Bool) {
	register_command(matcher, option, true);
	return;

but it seemed less appropriate (no other similar checks).

Letting it handle like other experimental flags (code below) is not an option either since in this case we have to do with a CompileCommand.

jdk/src/hotspot/share/runtime/flags/jvmFlag.cpp

Lines 112 to 118 in f629152

	if (is_experimental() && !is_unlocked()) {
	jio_snprintf(buf, buflen,
	"Error: VM option '%s' is experimental and must be enabled via -XX:+UnlockExperimentalVMOptions.\n"
	"Error: The unlock option must precede '%s'.\n",
	_name, _name);
	return JVMFlag::EXPERIMENTAL_FLAG_BUT_LOCKED;
	}

---

Progress

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Issue

• JDK-8303069: Memory leak in CompilerOracle::parse_from_line

Reviewers

• Tobias Hartmann (@TobiHartmann - Reviewer)
• Justin King (@jcking - Committer)

Reviewing

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[TobiHartmann]

Looks good to me.

[openjdk]

@dafedafe This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8303069: Memory leak in CompilerOracle::parse_from_line

Reviewed-by: thartmann, jcking

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 27 new commits pushed to the master branch:

• b2639e1: 8304164: jdk/classfile/CorpusTest.java still fails after JDK-8303910
• 620564a: 8304130: Add runtime/StackGuardPages/TestStackGuardPagesNative.java to ProblemList.txt
• 9d518c5: 8299375: [PPC64] GetStackTraceSuspendedStressTest tries to deoptimize frame with invalid fp
• ebac7ee: 8304063: tools/jpackage/share/AppLauncherEnvTest.java fails when checking LD_LIBRARY_PATH
• 36995c5: 8304242: CPUInfoTest fails because "serialize" CPU feature is not known
• 6b42275: 7154070: in SwingSet2, switching between LaFs it's easy to lose JTable dividers
• 8eed7de: 8304146: Refactor VisibleMemberTable (LocalMemberTable)
• a487a27: 8303150: DCmd framework unnecessarily creates a DCmd instance on registration
• 2e987d7: 8304360: Test to ensure ConstantDescs fields work
• 2f23c80: 8304225: Remove javax/script/Test7.java from ProblemList
• ... and 17 more: https://git.openjdk.org/jdk/compare/01e6920581407bc3bd69db495fc694629ef01262...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@TobiHartmann, @jcking) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[mlbridge]

Webrevs

• 00: Full (d8b69ae2)

[dafedafe]

Thanks a lot @TobiHartmann @jcking for your reviews!

[dafedafe]

/integrate

[openjdk]

@dafedafe
Your change (at version d8b69ae) is now ready to be sponsored by a Committer.

[TobiHartmann]

/sponsor

[openjdk]

Going to push as commit 384a8b8.
Since your change was applied there have been 29 commits pushed to the master branch:

• 6dd6c15: 8301684: Fix test code to not get finalizer deprecation warnings
• cb4ae19: 8292059: Do not inline InstanceKlass::allocate_instance()
• b2639e1: 8304164: jdk/classfile/CorpusTest.java still fails after JDK-8303910
• 620564a: 8304130: Add runtime/StackGuardPages/TestStackGuardPagesNative.java to ProblemList.txt
• 9d518c5: 8299375: [PPC64] GetStackTraceSuspendedStressTest tries to deoptimize frame with invalid fp
• ebac7ee: 8304063: tools/jpackage/share/AppLauncherEnvTest.java fails when checking LD_LIBRARY_PATH
• 36995c5: 8304242: CPUInfoTest fails because "serialize" CPU feature is not known
• 6b42275: 7154070: in SwingSet2, switching between LaFs it's easy to lose JTable dividers
• 8eed7de: 8304146: Refactor VisibleMemberTable (LocalMemberTable)
• a487a27: 8303150: DCmd framework unnecessarily creates a DCmd instance on registration
• ... and 19 more: https://git.openjdk.org/jdk/compare/01e6920581407bc3bd69db495fc694629ef01262...master

Your commit was automatically rebased without conflicts.

[openjdk]

@TobiHartmann @dafedafe Pushed as commit 384a8b8.

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