RFR: 8299795: Relativize locals in interpreter frames [v4]

[Fredrik Bredberg]

On Tue, 17 Jan 2023 13:32:47 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>> Fredrik Bredberg 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 five additional commits since the last revision:
>> 
>>  - Merge branch 'master' into relativize-locals-JDK-8299795_2023-01-09
>>  - Added references to JDK-8300197
>>  - Updated some copyright dates.
>>  - Changed copyright date to 2023
>>  - 8299795: Relativize locals in interpreter frames
>
> src/hotspot/cpu/ppc/templateInterpreterGenerator_ppc.cpp line 1035:
> 
>> 1033:   __ sub(R12_scratch2, R18_locals, R1_SP);
>> 1034:   __ srdi(R12_scratch2, R12_scratch2, Interpreter::logStackElementSize);
>> 1035:   // Now &fp()[R12_scratch2] == R18_locals
> 
> I think this comment makes no sense. Please remove it. Otherwise, PPC64 code LGTM.

My intention was to show how the contents of R18_locals (the absolute address to locals) can be recreated by using R12_scratch2 as an index from the frame pointer. Before we stored R18_locals in the stackframe, now we store R12_scratch2. Does that make more sense?

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PR: https://git.openjdk.org/jdk/pull/11902