[libcxx-commits] [libcxx] [libc++] Allows any types of size 4 and 8 to use native platform ulock_wait (Proof of Concept) (PR #161086)

[Louis Dionne via libcxx-commits]

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ldionne wrote:

You should introduce this behind an ABI macro. I think the easiest way to do that is probably to constrain the set of types that you perform this optimization for to be just `uin64_t` when we're being ABI compatible.

Also, we're introducing new symbols to the dylib. That means we need to handle back deployment. You'll need to add an entry to `__configuration/availability.h` (we have examples there), and only call your new symbols in the dylib when the deployment target supports that. It's not difficult, but it will be a bit of a challenge to refactor things so that you can still call the old symbols.

https://github.com/llvm/llvm-project/pull/161086