RFR: 8341862: PPC64: C1 unwind_handler fails to unlock synchronized methods with LM_MONITOR

[Martin Doerr]

On Mon, 14 Oct 2024 13:51:21 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

> Make sure `LIR_Assembler::emit_unwind_handler()` jumps to the slow path directly for unlocking a synchronized method if `LM_MONITOR` is used.
> On the fast paths assertions are added that the mode is actually handled.
> 
> The change passed our CI testing:
> Tier 1-4 of hotspot and jdk. All of Langtools and jaxp. Renaissance Suite and SAP specific tests.
> Testing was done on the main platforms and also on Linux/PPC64le and AIX.

Good catch! LGTM.

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Marked as reviewed by mdoerr (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21497#pullrequestreview-2366762944