[clang] [llvm] [AArch64][PAC] Sign block addresses used in indirectbr. (PR #97647)

[Daniil Kovalev via cfe-commits]

https://github.com/kovdan01 commented:

The changes mostly look reasonable, but there are several comments to be answered before the PR can be merged.

Regarding previous @efriedma-quic 's comment about computing the difference between two blockaddresses - I suppose it might be OK just to explicitly do not support this as for now and implement+test a proper error message (if it's too time-consuming to have full support right now).

https://github.com/llvm/llvm-project/pull/97647