RFR: 8254693: Add Panama feature to pass heap segments to native code [v12]

[Yasumasa Suenaga]

On Fri, 27 Oct 2023 11:28:29 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>> @YaSuenag `r12` is restored in `reinit_heapbase()` if needed and no, `r12` does not need remembering because it is a constant and can be restored from somewhere else.
>
> I think your code is fine. Restoring `r12_heapbase` at this point is not bad because `runtime_call` is only for slow paths. I don't think it should be moved.

Thanks everyone! I understood `r12` is restored in `reinit_heapbase()`. It is necessary. I have no comments.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16201#discussion_r1374678254