RFR: 8339416: [s390x] Provide implementation for resolve_global_jobject [v2]

[Martin Doerr]

On Mon, 16 Sep 2024 04:56:36 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> This PR provides "resolve_global_jobject" method implementation for s390x-port. 
>> 
>> Testing:
>> * Tier1 test with Fastdebug; 
>> * Added these changes on top of https://github.com/openjdk/jdk/pull/20479 and modified the call in the stubGenerator_s390.cpp file; 
>> *  1. Ran tier1 test with a call to  "resolve_jobect"
>> *  2. Ran tier1 test with a call to  "resolve_global_jobject" 
>> 
>> I didn't see any new failure appearing there.
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   removes extra line

Looks correct to me.

src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.cpp line 108:

> 106: }
> 107: 
> 108: // Generic implementation. GCs can provide an optimized one.

You may want to implement an optimized `G1BarrierSetAssembler::resolve_jobject` and `ModRefBarrierSetAssembler::resolve_jobject`. Otherwise, those GCs may get a regression.

src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.cpp line 146:

> 144: 
> 145:   __ z_ltgr(value, value);
> 146:   __ z_bre(done); // null as-is.

"Use null as-is." sounds better.

-------------

PR Review: https://git.openjdk.org/jdk/pull/20986#pullrequestreview-2307174155
PR Review Comment: https://git.openjdk.org/jdk/pull/20986#discussion_r1761487260
PR Review Comment: https://git.openjdk.org/jdk/pull/20986#discussion_r1761487962