RFR: 8350182: [s390x] Relativize locals in interpreter frames [v2]

[Lutz Schmidt]

On Tue, 25 Feb 2025 13:18:38 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> Port for [JDK-8299795](https://bugs.openjdk.org/browse/JDK-8299795) Relativize Z_locals in interpreter frame for s390x.
>> 
>> Tier1  test with fastdebug vm are clean.
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   use Z_R0 as helper

Changes requested by lucy (Reviewer).

src/hotspot/cpu/s390/templateInterpreterGenerator_s390.cpp line 1145:

> 1143:   __ z_stg(Z_R1, _z_ijava_state_neg(locals), fp);
> 1144: 
> 1145:   __ z_lgr(Z_R1, Z_R0); // restore R1

Why don't you use Z_R0 for the relativation calculations and leave Z_R1 untouched? That will avoid the save/restore overhead.

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PR Review: https://git.openjdk.org/jdk/pull/23660#pullrequestreview-2738650289
PR Review Comment: https://git.openjdk.org/jdk/pull/23660#discussion_r2026285061