[llvm] [Support] Add clang tooling generated explicit visibility macros (PR #113097)

[kadir çetinkaya via llvm-commits]

kadircet wrote:

I am not really an owner around these bits, hence I only have some high level concerns (that shouldn't be blocking if actual owners don't feel the same).

It's completely unclear how the APIs to be exposed were chosen, and how it'll be kept up-to-date. I think this will turn into a maintenance nightmare for everyone going forward. People will keep tagging their new symbols as LLVM_ABI, without really understanding why (just because existing code does it that way), people will also keep breaking you as these attributes can be dropped during refactorings unintentionally etc. Moreover I don't see how this solves windows' 65k symbol limit per shared-library. Surely this will delay the inevitable, but inherently we still have a single library that exposes all the symbols.

Have you considered any alternatives ? Is it possible to have a finer granular built for windows? Can we describe set of symbols to expose through a side-table instead ?

https://github.com/llvm/llvm-project/pull/113097