[llvm] [DirectX] Infrastructure to collect shader flags for each function (PR #112967)

[Damyan Pepper via llvm-commits]

https://github.com/damyanp commented:

Thanks, this is looking good. I think my remaining opens are really nits.

We should look for someone more expert in this area to approve though.

https://github.com/llvm/llvm-project/pull/112967