RFR: 8316523: Relativize esp in interpreter frames (PowerPC only) [v2]

[Erik Österlund]

On Mon, 2 Oct 2023 09:25:06 GMT, Fredrik Bredberg <fbredberg 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.
>
> Fredrik Bredberg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Updated after review.

Seems reasonable.

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Marked as reviewed by eosterlund (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15999#pullrequestreview-1657123557