RFR: 8325821: [REDO] use "dmb.ishst+dmb.ishld" for release barrier [v6]

[kuaiwei]

On Fri, 31 May 2024 11:02:31 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> kuaiwei has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add comment in aarch64.ad
>
> src/hotspot/cpu/aarch64/macroAssembler_aarch64.hpp line 153:
> 
>> 151:     Assembler::bind(L);
>> 152:     code()->clear_last_insn();
>> 153:     code()->set_last_label(pc());
> 
> OK, so we have added `_last_label` to shared code in `codeBuffer`, but only update it in aarch64. This would be surprising for other platforms. On the other hand, this is what we already do with `_last_insn` -- only implementing it for specific platforms. Probably fine, but it would be nice to strengthen this with asserts, maybe in separate PR.

It reminds me it could be applied to riscv. It also need merge membar. I will move this part to a new PR.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19278#discussion_r1622318763