[libcxx-commits] [libcxxabi] [libcxx] [libc++] Split the monolithic __threading_support header (PR #79654)

[Nico Weber via libcxx-commits]

nico wrote:

> Would there be any appetite on your end to update both at the same time?

Unless absolutely necessary, no :) Updating LLVM can be a lot of work. The more parts of it we can ship independently, the better. libcxx is one of the harder parts to update, so I wouldn't want us to tie anything to it unless we want to.

(We'd prefer to move in the opposite direction: We currently bundle the sanitizer runtimes with the compiler/linker package, and it'd be nice if they'd update separately for example. The sanitizer runtimes have been pretty stable the last few years though, so it's not a priority.)

> I will remove the work-around by EOW -- is that fine?

Is it expensive to keep around for a bit longer? At the moment, updating libc++ is blocked on removing an is_pod somewhere in our codebase, but it's in a dependency that needs to roll in both my cherry-pick and a bunch of related things, and the new version of the dependency has some msan issues at the moment, etc. Fixing things in dependencies can take a while since we don't fully control them. (For example, https://crbug.com/1481891 – the `_LIBCPP_CHAR_TRAITS_REMOVE_BASE_SPECIALIZATION` thing – took three months to resolve)

https://github.com/llvm/llvm-project/pull/79654