[libunwind] [llvm] [LFI][AArch64] Add AArch64 LFI rewriter (PR #184277)

[Alexis Engelke via cfe-commits]

https://github.com/aengelke commented:

I'm a bit concerned about the switch tables. I feel that we should have most of this information somewhere already. If we use additional TSFlags, IMHO they should be used in a way that also benefits the rest of the code base. (How many TSFlags bits remain?)

I haven't reviewed the AArch64 instruction part in detail.

https://github.com/llvm/llvm-project/pull/184277