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

[Erich Keane via cfe-commits]

erichkeane wrote:

> So my understanding was that the annotate attribute didn't modify codegen (and thus LLVM string attributes), but perhaps I didn't use it properly.
> 
> Is there any reference for that?

I'm not sure what you mean by that?  the 'annotate' attribute just ends up in an LLVM-string-attribute being placed on the decl/type/etc.  Unfortunately it isn't documented (as it is the 'hidden' attribute you suggested!), but you can see some examples in clang/test/CodeGen (just grep for annotate).

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