[PATCH] D65653: [AArch64] Change location of frame-record within callee-save area.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc added a comment.

So I believe that after this change, we are no longer guaranteed that FP + 16 = SP at exit, correct? I think this would be a requirement for a "fast" unwinder that works by following frame pointers (rather than reading unwind info) and is capable of decrypting return addresses of functions built with -msign-return-addresses (because the AUT instruction would need to know SP at exit). If this is the case, would it be feasible to let a platform opt out of this behaviour? (I realise that Darwin is opted out, but I don't know about the SVE support status there.) I'm not very familiar with SVE, but I would imagine that you could use a different register for this purpose on opted out platforms.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D65653/new/

https://reviews.llvm.org/D65653