[clang] [Clang][AMDGPU] Add a builtin for llvm.amdgcn.make.buffer.rsrc intrinsic (PR #95276)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

> > I am wondering whether prefix the builtin type with `__amdgcn_` would be better since I envision risk of conflicting with reserved names of other compilers or standard libraries.
> 
> In the patch where the type was introduced we had a brief back-and-forth. I checked the reference type WASM introduced and they don't have prefix. I don't think in the future we'd have a cross-platform/-compiler type called `__buffer_rsrc_t`, and if it happens, it is not supposed to have `__` prefix. However, I'm by no means a language expert, so I'm fine if we really want to add that.

we are introducing `__buffer_rsrc_t` in global namespace, which is seen in any other namespace. Imagine some libstdc++ or libc++ header files use the same name in some namespaces and a HIP program includes these header files, there may be compilation error.

A search of `__buffer` shows libstdc++ and libc++ do use names starting with `__buffer`:

https://github.com/search?q=repo%3Agcc-mirror%2Fgcc%20path%3A%2F%5Elibstdc%5C%2B%5C%2B-v3%5C%2Finclude%5C%2F%2F%20__buffer&type=code

https://github.com/search?q=repo%3Allvm%2Fllvm-project+path%3A%2F%5Elibcxx%5C%2F%2F+__buffer&type=code&p=1

I understand the chance of conflict is low. It may be like the chance of hitting by a meteor. However, if we prefix with `__amdgcn_`, there is no such risk. And we have the benefit to clearly indicate it is a amdgcn target-specific type.

https://github.com/llvm/llvm-project/pull/95276