[clang] [C++20] [Modules] Introduce a tool 'clang-named-modules-querier' and two plugins 'ClangGetUsedFilesFromModulesPlugin' and 'ClangGetDeclsInModulesPlugin' (PR #72956)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

> I'm still really hesitant about this direction.
> 
> One starting concern: what happens if someone adds an overload, or other interesting name resolution to the module? The downstream caller hasn't textually changed, but it should be rebuilt because it should be calling a different overload candidate now? (& even if we then track every function with the same name, there's other cases - like adding an implicit conversion operator, operator overload, etc, that might complicate things)

Oh, nice catch. It is a problem for the used file based solution if we add the overload to a separate unused files. While the hash based solution can handle the overloads case, it'll be a problem if we add an implicit conversion we didn't use before.

https://github.com/llvm/llvm-project/pull/72956