[libcxx-commits] [libcxx] [libc++] Introduce ABI sensitive areas to avoid requiring _LIBCPP_HIDE_FROM_ABI everywhere (PR #131156)

[Aaron Ballman via libcxx-commits]

AaronBallman wrote:

> > But if we do something in the compiler about how visibility is inherited from the namespace, it should probably not be specific to `std`.
> 
> Definitely. My question is mostly what behaviour we actually want.

My intuition is that inheriting visibility from the namespace would be in line with how the standard functionality already works for linkage. e.g., users are used to "everything within this unnamed namespace has internal linkage" so "everything within this namespace with this marking about linkage has that linkage" is not a stretch. Whatever visibility is specified on the declaration within the namespace should take precedence over what's specified on the namespace.

CC @ErichKeane for more opinions as attributes code owner.

https://github.com/llvm/llvm-project/pull/131156