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

[Oliver Hunt via libcxx-commits]

ojhunt wrote:

> @ojhunt Thanks for an update! I've resolved several threads, but some things should still be fixed.
> 
> Please let me know if you have any comments/questions or any help is needed from my side.
> 
> ### Trivial style-related issues
> These require almost zero effort to apply. Please consider fixing these first so we do not need to worry about them anymore.
> 
> 1. [[runtimes][PAC] Harden unwinding when possible #143230 (comment)](https://github.com/llvm/llvm-project/pull/143230#discussion_r2388284017)
> 2. [[runtimes][PAC] Harden unwinding when possible #143230 (comment)](https://github.com/llvm/llvm-project/pull/143230#discussion_r2388324262)
> 3. [[runtimes][PAC] Harden unwinding when possible #143230 (comment)](https://github.com/llvm/llvm-project/pull/143230#discussion_r2388325718)

I think fixed?

> 
> ### Non-trivial styling-related issues
> Refactor preprocessor checks against ptrauth. See thread [#143230 (comment)](https://github.com/llvm/llvm-project/pull/143230#discussion_r2369029642) and proposed fix [644405b](https://github.com/llvm/llvm-project/commit/644405b56cfa59dd3787119182df087dff6e756c)

That sounds ok

> 
> ### Breaking change to be reverted
> > > ### An issue causing a runtime crash
> > > Do not mix pac-ret and ptrauth_returns. See thread https://github.com/llvm/llvm-project/pull/143230/files#r2369419226 and commit [ced8b99](https://github.com/llvm/llvm-project/commit/ced8b99373c9b0756f1718999996f44a74bdf46d).
> > 
> > 
> > Fixed with an arm64e guard.
> 
> This does not seem to fix the originally described issue, moreover, it looks like this breaks previously working behavior. See [#143230 (comment)](https://github.com/llvm/llvm-project/pull/143230#discussion_r2388356981).

Minor detail :D

I think fixed correctly now (based on what you posted) but I need to verify the correct thing happens on arm64e (this will take a few days).

There's still the ifdef'd definition of the helper function in the current version, but I'll move that around in a bit.

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