[libcxx-commits] [libcxx] [libc++] Introduce implicit and explicit ABI annotations (PR #193045)

[Nikolas Klauser via libcxx-commits]

philnik777 wrote:

@vonosmas Some amount of compile time hit is expected, since this is currently mostly dead code. However, once we remove the explicit annotations I expect it will actually slightly improve compile times. However, I do remember pushing and popping diagnostics can be quite expensive with Clang modules, so I've opened #200338 for that.

Re. `_LIBCPP_NO_ABI_TAG`, I'm somewhat skeptical that that the TODO will ever be resolved. Even if we have compression mangling, the same argument about increased size holds. IMO we should just bite the bullet and remove the flag entirely, since it does provide (IMO quite significant) value in environments with mixed configurations. However, if you insist I'm OK with making the pragmas respect it for now and we can talk about what to do about this flag later.

https://github.com/llvm/llvm-project/pull/193045