RFR: 8339386: Assertion on AIX - original PC must be in the main code section of the compiled method

[Richard Reingruber]

On Wed, 25 Sep 2024 19:20:22 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> We should make sure to read the `sender_pc` only once to make it signal safe (e.g. using `volatile`). Now, we can check if it is a deopt PC and if so, if the original PC is within the nmethod.
> In case of interpreter frame on top of compiled deoptimized frame we need to use the unextendedSP (2nd commit).

I'd expect more frequent failures of the assertion given that the wrong unextended sp was used. It shouldn't be too difficult to write a reproducer but that's not really needed.
The fix does look good.
Thanks, Richard.

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Marked as reviewed by rrich (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21189#pullrequestreview-2348293871