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

[Nikita Popov via llvm-commits]

================

----------------
nikic wrote:

Hm, do you have any idea what fraction of classes are like that? This seems like a bit of a foot-gun, as someone adding an out of line member is likely not going to check whether this is the first out of line member in the class and they have to add an ABI annotation.

Or is it expected that automation is going to check that all necessary annotations are present and we instead have to explicitly mark things that we *don't* want part of the ABI (with which macro? It is still the LIBRARY_VISIBILITY one?)

Generally I'd appreciate it if the PR included some useful context on what the wider maintenance plan here is supposed to be.

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