RFR: 8362193: Re-work MacOS/AArch64 SpinPause to handle SB

[Aleksey Shipilev]

On Fri, 18 Jul 2025 14:17:55 GMT, Evgeny Astigeevich <eastigeevich at openjdk.org> wrote:

> > Overall, I think it is not very reasonable to pull things into shared parts, when that deviates significantly from the common Hotspot way of handling things. I don't think it even saves us any duplication to move implementations to `spin_wait_aarch64.(inline.)pp`? So I suggest we don't.
> 
> Do I understand you correctly we should not have `exec_spin_wait_inst` and `generate_spin_wait`?

Yes. I don't see a benefit for them? Collecting everything related to spin wait implementation is not worth it, IMO. We have duplication by asm-stubs, macroassembler, c1_assembler, c2.ad rules for the arch-specific code already.

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PR Comment: https://git.openjdk.org/jdk/pull/26387#issuecomment-3089741127