8253412: Unsupported GC options passed in JAVA_TOOL_OPTIONS are silently ignored

[shipilev]

See the reproducer in the bug itself. I think that happens because GCConfig checks only for FLAG_IS_CMDLINE, which is only from cmdline-originated flags. In this case, the flag comes from the environment variable. Maybe checking for !FLAG_IS_DEFAULT is better, as it captures all non-default origins.

But them, instead of checking for FLAG_IS_CMDLINE, I think we can rely on the fact that all Use*GC options are false by default. So if any of such flags is true, it means something had selected the GC. This allows for some further simplification of the macro (although I am not sure if it was intended to be ever used to check -XX:-* flags).

Attention @pliden.

Testing:

• Ad-hoc reproducer now passes
• Linux x86_64 fastdebug tier1
• Linux x86_64 fastdebug tier2

---

Progress

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Issue

• JDK-8253412: Unsupported GC options passed in JAVA_TOOL_OPTIONS are silently ignored

Reviewers

• Per Lidén (@pliden - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/282/head:pull/282
$ git checkout pull/282

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[openjdk]

@shipilev The following label will be automatically applied to this pull request: hotspot-gc.

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[mlbridge]

Webrevs

• 00: Full (07931b0)

[pliden]

FLAG_IS_CMDLINE is often used as "FLAG_IS_USERSPECIFIED". So I have the feeling many (most?) uses of FLAG_IS_CMDLINE is semi-broken, given that options coming in through JAVA_TOOLS_OPTIONS and _JAVA_OPTIONS isn't considered part of the command-line.

Anyway, this change looks good to me.

[openjdk]

@shipilev This change now passes all automated pre-integration checks. In addition to the automated checks, the change must also fulfill all project specific requirements

After integration, the commit message will be:

8253412: Unsupported GC options passed in JAVA_TOOL_OPTIONS are silently ignored

Reviewed-by: pliden

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Since the source branch of this PR was last updated there have been 16 commits pushed to the master branch:

• 96f722c: 8252114: Windows-AArch64: Enable and test ZGC and ShenandoahGC
• f7b1ce4: 8253447: Remove buggy code introduced by 8249451
• 282b9dc: 8081833: Clean up JVMFlag getter/setter code
• 0e98fc1: 8253237: [REDO] Improve large object handling during evacuation
• d1f9b8a: 8234808: jdb quoted option parsing broken
• d8921ed: 8247281: migrate ObjectMonitor::_object to OopStorage
• f800af9: 8241390: 'Deadlock' with VM_RedefineClasses::lock_classes()
• 2e30ff6: 8253311: Cleanup relocInfo constructors
• 43be5a3: 8230652: Improve verbose output
• 5a7390b: 8253418: ZGC: Use pd_ prefix to denote platform dependent code
• ... and 6 more: https://git.openjdk.java.net/jdk/compare/34ec1bedd1c2d774c52f3664f9b57a4422877bfe...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid automatic rebasing, please merge master into your branch, and then specify the current head hash when integrating, like this: /integrate 96f722cf63ae0e115612d816aa339d38074d3ade.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[shipilev]

/integrate

[openjdk]

@shipilev Since your change was applied there have been 16 commits pushed to the master branch:

• 96f722c: 8252114: Windows-AArch64: Enable and test ZGC and ShenandoahGC
• f7b1ce4: 8253447: Remove buggy code introduced by 8249451
• 282b9dc: 8081833: Clean up JVMFlag getter/setter code
• 0e98fc1: 8253237: [REDO] Improve large object handling during evacuation
• d1f9b8a: 8234808: jdb quoted option parsing broken
• d8921ed: 8247281: migrate ObjectMonitor::_object to OopStorage
• f800af9: 8241390: 'Deadlock' with VM_RedefineClasses::lock_classes()
• 2e30ff6: 8253311: Cleanup relocInfo constructors
• 43be5a3: 8230652: Improve verbose output
• 5a7390b: 8253418: ZGC: Use pd_ prefix to denote platform dependent code
• ... and 6 more: https://git.openjdk.java.net/jdk/compare/34ec1bedd1c2d774c52f3664f9b57a4422877bfe...master

Your commit was automatically rebased without conflicts.

Pushed as commit a4affd5.

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