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

[Sami Tolvanen via cfe-commits]

samitolvanen wrote:

> > AFAIK the use case for KCFI is very narrow: the x86-64 Linux kernel.
> 
> At the very least, it's also used in the arm64 Linux Kernel.

Linux also supports KCFI on 32-bit ARM and RISC-V. However, this change seems to only affect X86.

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