[compiler-rt] [libcxxabi] [libunwind] [runtimes][PAC] Harden unwinding when possible (#138571) (PR #143230)

[Oliver Hunt via llvm-commits]

ojhunt wrote:

Re: the oracle concerns - there are some protections we have, but in general I think the current pointer auth semantics/diagnostics make it too easy to silently introduce oracles. Additionally a lot of the current unwind pointerauth work is focused on protecting the ABI boundaries in the knowledge we can improve the internals over time.

I've once again acquired some higher priority work but I should be getting back to this tonight or over the weekend.

https://github.com/llvm/llvm-project/pull/143230