https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103726
--- Comment #12 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:265d3e1a4e3d6c71d354f859302f023dc2d33f62 commit r12-6474-g265d3e1a4e3d6c71d354f859302f023dc2d33f62 Author: Jonathan Wakely <jwak...@redhat.com> Date: Mon Jan 10 20:48:53 2022 +0000 libstdc++: Install <coroutine> header for freestanding [PR103726] The standard says that <coroutine> should be present for freestanding. That was intentionally left out of the initial implementation, but can be done without much trouble. The header should be moved to libsupc++ at some point in stage 1. The standard also says that <coroutine> defines a std::hash specialization, which was missing from our implementation. That's a problem for freestanding (see LWG 3653) so only do that for hosted. We can use concepts to constrain the __coroutine_traits_impl base class when compiled with concepts enabled. In a pure C++20 implementation we would not need that base class at all and could just use a constrained partial specialization of coroutine_traits. But the absence of the __coroutine_traits_impl<R, void> base would create an ABI difference between the non-standard C++14/C++17 support for coroutines and the same code compiled as C++20. If we drop support for <coroutine> pre-C++20 we should revisit this. libstdc++-v3/ChangeLog: PR libstdc++/103726 * include/Makefile.am: Install <coroutine> for freestanding. * include/Makefile.in: Regenerate. * include/std/coroutine: Adjust headers and preprocessor conditions. (__coroutine_traits_impl): Use concepts when available. [_GLIBCXX_HOSTED] (hash<coroutine_handle>): Define.
