[llvm] [BOLT][AArch64] Handle OpNegateRAState to enable optimizing binaries with pac-ret hardening (PR #120064)

[Gergely Bálint via llvm-commits]

bgergely0 wrote:

Hi @maksfb @paschalis-mpeis 

I looked at how unwinding works _from Stubs_, and opened this issue: https://github.com/llvm/llvm-project/issues/160989.

TLDR: while executing the Stubs, we cannot unwind as it is, so PAC-specific unwinding will also not work. In fact, to match the unwind info, it makes sense to have the same RAState in the stub, as before it.

For other new instructions, I think we can perfectly match the RAState (I don't expect other places where a Block is jumped over, so it is not part of the CFG of the function it is placed in).

https://github.com/llvm/llvm-project/pull/120064