On Wed, 30 Nov 2022 21:34:59 GMT, Dean Long <dl...@openjdk.org> 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