[clang] [Clang][HTO] Add clang attribute for propagating llvm-level information (PR #83059)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

There are a few things in how the `handle` function works that are incorrect/not necessary, but like Aaron, I'm pretty solidly against this patch in concept.  Aaron had some good reasoning, and mine opinion reflects all of it.

https://github.com/llvm/llvm-project/pull/83059