RFR: 8350398: [s390x] Relativize initial_sp/monitors in interpreter frames

[Lutz Schmidt]

On Mon, 5 May 2025 04:47:56 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> s390x port for [JDK-8315966](https://bugs.openjdk.org/browse/JDK-8315966). 
>> 
>> This PR depends on https://github.com/openjdk/jdk/pull/23660 because index calculation macro will be added by that PR, which is being used by this one. 
>> 
>> 
>> // Frame slot index relative to fp
>> #define _z_ijava_idx(_component) \
>>         (_z_ijava_state_neg(_component) >> LogBytesPerWord)
>
> src/hotspot/cpu/s390/interp_masm_s390.cpp line 689:
> 
>> 687:   stop("Z_fp is corrupted");
>> 688:   bind(ok);
>> 689: #endif // ASSERT
> 
> Hi @RealLucy, 
> should I remove or keep this check here ? I wouldn't harm in release build anyway, but for debug build the size of `BTB` table will increase. Look `TemplateTable_s390.cpp` changes.

Well,
it's a tradeoff between space consumption and code safety. I personally would leave the check in as long as we do not run into space limitations. If you would like to keep the code more compact, and remove the #ASSERT blocks, that's ok for me too.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23708#discussion_r2077636409