[libcxx-commits] [libcxx] [libc++] Refactor the Windows and MinGW implementation of the locale base API (PR #115752)

[Louis Dionne via libcxx-commits]

ldionne wrote:

Thanks for chiming in.

> But I would request that this isn't treated as blanket permission to break the whole ABI

Ack. I am putting up the "cleanest" version of this patch which removes the old symbols that are not needed anymore. However, if backwards compatibility is required, we could embed these historically significant symbols into the shared library. There's a number of ways we can do that. We could use aliases if that's a thing on Windows, or we could simply define the old name in a separate `.cpp` file similar to what we're doing in `libcxx/src/legacy_pointer_safety.cpp` (but with a real implementation). I wanted to have a discussion before I started making this patch more complicated for ABI guarantees I wasn't sure mattered.

> are they implicitly embedded in many cases, or are they only referenced if the user code explicitly uses locale things

I do think that older binaries are going to have references to those symbols, so that means running the binary against a new version of the library would fail with undefined references.

https://github.com/llvm/llvm-project/pull/115752