RFR: 8319799: Recursive lightweight locking: x86 implementation [v14]

[Axel Boldt-Christmas]

On Fri, 26 Jan 2024 21:23:40 GMT, Daniel D. Daugherty <dcubed 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 21 additional commits since the last revision:
>> 
>>  - Merge remote-tracking branch 'upstream_jdk/pr/16606' into JDK-8319799
>>  - Update variable names in ad files
>>  - Preload markWord unconditionally
>>  - 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  - Remove outdated anonymous owner fix in stub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
>>  - ... and 11 more: https://git.openjdk.org/jdk/compare/c61122da...4d37c4b7
>
> src/hotspot/cpu/x86/c1_MacroAssembler_x86.cpp line 142:
> 
>> 140: #else
>> 141:     // This relies on the implementation of lightweight_unlock knowing that it
>> 142:     // will clobber its thread when using EAX.
> 
> This use of `EAX` is confusing when earlier in this function `rax` is used.

Hm, I thought RAX was confusing when used in x86_32 code. But can try to clarify.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16607#discussion_r1469687375