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8288360: CI: ciInstanceKlass::implementor() is not consistent for well-known classes #9147

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@iwanowww iwanowww commented Jun 13, 2022

ciInstanceKlass::implementor() doesn't cache the result for well-known interfaces (is_shared() == true). Due to concurrent class loading, compilers can observe a change in reported unique implementor (in the worst case: from having no implementors to having one, then to having many) thus introducing paradoxical situations during a compilation.

What makes it very hard/impossible to trigger the bug is there's only a single well-known interface (java.util.Iterable) present as of now, which gets multiple implementors loaded early during startup.

Testing: hs-tier1 - hs-tier2


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  • JDK-8288360: CI: ciInstanceKlass::implementor() is not consistent for well-known classes



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bridgekeeper bot commented Jun 13, 2022

👋 Welcome back vlivanov! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

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openjdk bot commented Jun 13, 2022

@iwanowww The following label will be automatically applied to this pull request:

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@openjdk openjdk bot added the hotspot-compiler label Jun 13, 2022
@iwanowww iwanowww marked this pull request as ready for review June 13, 2022 21:31
@openjdk openjdk bot added the rfr Pull request is ready for review label Jun 13, 2022
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@TobiHartmann TobiHartmann left a comment

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Looks good to me. Since the bug is a P2 and we are in RDP 1, we either need to re-target the fix to JDK 19 or explicitly defer to JDK 20 (see

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openjdk bot commented Jun 14, 2022

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

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

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

8288360: CI: ciInstanceKlass::implementor() is not consistent for well-known classes

Reviewed-by: thartmann

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 9 new commits pushed to the master branch:

  • 03dca56: 8287525: Extend IR annotation with new options to test specific target feature.
  • 86c9241: 8287028: AArch64: [vectorapi] Backend implementation of VectorMask.fromLong with SVE2
  • fbe9266: 8288378: [BACKOUT] DST not applying properly with zone id offset set with TZ env variable
  • 1904353: Merge
  • 7aafc69: 8288105: [PPC64] Problems with -XX:+VerifyStack
  • f4b05a1: 8288173: JDK-8202449 fix causes conformance test failure : api/java_util/Random/RandomGenerator/NextFloat.html
  • d9c1364: 8288101: False build warning-as-error with GCC 9 after JDK-8214976
  • a9c2ab6: 8288080: (fc) FileChannel::map for MemorySegments should state it always throws UOE
  • e90b579: 8288332: Tier1 validate-source fails after 8279614

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@openjdk openjdk bot added the ready Pull request is ready to be integrated label Jun 14, 2022
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Thanks for the review, Tobias.

I've retargeted the fix to 19 (openjdk/jdk19#15).

@iwanowww iwanowww closed this Jun 14, 2022
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