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

[Daniil Kovalev via llvm-commits]

kovdan01 wrote:

> (if linux folk could retest to see how badly I have broken everything that would be great)

@ojhunt A couple of quick observations:

1. It looks like that you forgot to add explicit declarations of copy constructor and assignment operator for `Registers_arm64`. Now, compiler complains about explicit definitions for these while they are implicitly defined.

2. Why do we need `static_assert(!__has_extension(ptrauth_qualifier));` under ifdefs for `_LIBUNWIND_USE_DL_ITERATE_PHDR`, `_LIBUNWIND_SUPPORT_DWARF_INDEX` and `_LIBUNWIND_ARM_EHABI`? These are failing for me (particularly the first two ones), and I'm not sure I understand why these static assertions are needed.

3. The PR title contains a reference to an old PR #138571, it's probably not needed


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