RFR: 8316523: Relativize esp in interpreter frames (PowerPC only)

[Fredrik Bredberg]

On Sun, 1 Oct 2023 14:41:47 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>> Relativize esp (Expression Stack Pointer on PowerPC) in interpreter frames.
>> 
>> By changing the "esp" member in interpreter frames from being an absolute address into an offset that is relative to the frame pointer, we don't need to change the value as we freeze and thaw frames of virtual threads. This is since we might freeze and thaw from and to different worker threads, so the absolute address to locals might change, but the offset from the frame pointer will be constant.
>> 
>> This subtask only handles "esp" on PowerPC. The relativization of other interpreter frame members are handled in other subtasks to [JDK-8289296](https://bugs.openjdk.org/browse/JDK-8289296).
>> 
>> It has been sanity tested onr PowerPC using Qemu.
>
> Thanks for taking care of PPC64! Looks correct. Seems like `relativize_one` and `derelativize_one` are no longer used and should better get removed?

Hi @TheRealMDoerr, do you want to wait some more for @reinrich to review this PR, or do you think it's ready to be integrated?

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PR Comment: https://git.openjdk.org/jdk/pull/15999#issuecomment-1748382012