RFR: 8319799: Recursive lightweight locking: x86 implementation [v12]

[Axel Boldt-Christmas]

On Wed, 24 Jan 2024 12:13:45 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> Axel Boldt-Christmas has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 18 additional commits since the last revision:
>> 
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Add more expressive stub continuation names
>>  - Remove outdated anonymous owner fix in stub
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Remove C2HandleAnonOMOwnerStub definitions on x86.
>>  - Add MFENCE comment
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - ... and 8 more: https://git.openjdk.org/jdk/compare/1a78ceb5...bc214b8d
>
> src/hotspot/cpu/x86/c1_MacroAssembler_x86.cpp line 63:
> 
>> 61:     testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
>> 62:     jcc(Assembler::notZero, slow_case);
>> 63:   } else if (LockingMode == LM_LIGHTWEIGHT) {
> 
> Same question as in the aarch64 version, why is it useful to move the header-load here?

I'll do the same unconditional preload change as in aarch64. To keep things simple.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16607#discussion_r1465984342