On Wed, 30 Nov 2022 21:34:59 GMT, Dean Long <[email protected]> wrote:
>> Andrew Haley has updated the pull request incrementally with one additional
>> commit since the last revision:
>>
>> Unused variable
>
> src/hotspot/cpu/aarch64/aarch64.ad line 3635:
>
>> 3633: }
>> 3634: } else if (_method->intrinsic_id() ==
>> vmIntrinsicID::_ensureMaterializedForStackWalk) {
>> 3635: __ nop();
>
> Please add a comment explaining why the nop is needed or desirable here.
It's there because C2 in this area is littered with bits of code that use magic
offsets, and I don't know how to find them all. It seemed safest to keep
everything the same size. Hence, a 4-byte NOP in AArch64 and a 5-byte NOP in
x86.
> src/hotspot/cpu/x86/x86_64.ad line 2174:
>
>> 2172: RELOC_DISP32);
>> 2173: } else if (_method->intrinsic_id() ==
>> vmIntrinsicID::_ensureMaterializedForStackWalk) {
>> 2174: __ addr_nop_5();
>
> Needs a comment. I guess this is because of how call sizes are computed.
Yes, that's my guess. I didn't want to change any offsets.
-------------
PR: https://git.openjdk.org/jdk/pull/10952
