RFR: 8345285: [s390x] test failures: foreign/normalize/TestNormalize.java with C2

[Martin Doerr]

On Wed, 22 Jan 2025 09:45:44 GMT, Andrew Haley <aph at openjdk.org> wrote:

> > Upcall stub frames and entry frames are always below the bottom frame.
> 
> Can you please explain this a little more? It's very confusing. Why is the logic here different from, say, x86 and AArch64? I guess it must be some difference to do with the shape of upcall stub frames and entry frames. Thanks.

The bottom frame already has the correct `sender_sp` from `push_skeleton_frame()`. Frames immediately on top of the entry frame or upcall stub frame are bottom frames. The solution is just to avoid overwriting the correct value.
The `sender_sp` computation at this point does not take everything into account (e.g. which frames were resized due to s390 or PPC64 ABI requirements) and may be wrong for bottom frames.

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PR Comment: https://git.openjdk.org/jdk/pull/23197#issuecomment-2607382386