RFR: 8308984: Relativize last_sp (and top_frame_sp) in interpreter frames [v2]

[Hao Sun]

On Thu, 10 Aug 2023 10:25:35 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.
>
> Fredrik Bredberg has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Updated linux-ppc64le after review
>  - Updated after review

src/hotspot/share/runtime/frame.cpp line 1624:

> 1622:       st->print_cr(" %s  %s %s", spacer, spacer, fv.description);
> 1623:     } else {
> 1624:       if (on_heap

Along with the removal of this check, `on_heap` is not used in this function.
Should we remove this parameter?

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PR Review Comment: https://git.openjdk.org/jdk/pull/14545#discussion_r1290855139