RFR: 8308984: Relativize last_sp (and top_frame_sp) in interpreter frames

[Fredrik Bredberg]

On Mon, 19 Jun 2023 15:59:15 GMT, Fredrik Bredberg <fbredberg at openjdk.org> wrote:

> Implementation of relativized last_sp (top_frame_sp on PowerPC) in interpreter frames for x64, aarch64, ppc64le and riscv.
> Not relativized last_sp on arm, zero and s390 but done some changes to cope with the changed generic code.
> 
> By changing the "last_sp" 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 "last_sp" (and its close equivalent "top_frame_sp" on PowerPC). The relativization of other interpreter frame members are handled in other subtasks to JDK-8289296.
> 
> Tested tier1-tier7 on supported platforms. The rest was sanity tested using Qemu.

I've done basic loom testing on ppc64le and riscv64 using Qemu, but would appreciate if @reinrich and @RealFYang could take it for a real test drive.

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PR Comment: https://git.openjdk.org/jdk/pull/14545#issuecomment-1655625280