[clang] [llvm] [X86] Enhance kCFI type IDs with a 3-bit arity indicator. (PR #117121)

[Scott Constable via llvm-commits]

scottconstable wrote:

> I haven't received a reply for my concerns I commented at [#117121 (comment)](https://github.com/llvm/llvm-project/pull/117121#issuecomment-2502346476) and [#117121 (comment)](https://github.com/llvm/llvm-project/pull/117121#issuecomment-2516251353), and they still remain for the alternative proposal.
> 
> I'd recommend working on better defining the problem, and then working on a well-defined solution for the problem that doesn't affect or conflict with a currently well-defined solution to a different problem (i.e., KCFI).

@rcvalle I think that https://github.com/llvm/llvm-project/pull/117121#issuecomment-2516251353 isn't relevant for the alternative proposal in https://github.com/llvm/llvm-project/pull/121070 because that proposal does not attempt to prevent cross-arity collisions. Do you agree? Or have I mis-understood your concern?

I'm not sure whether https://github.com/llvm/llvm-project/pull/117121#issuecomment-2502346476 is relevant for the alternative proposal. Please feel free to discuss at https://github.com/llvm/llvm-project/pull/121070.

https://github.com/llvm/llvm-project/pull/117121