There are a handful of standard library types that are intended
to support CTAD but don't need any explicit deduction guides to
do so.
This patch adds a dummy deduction guide to those types to suppress
-Wctad-maybe-unsupported (which gets emitted in user code).
This is a re-application of the original patch by Eric Fiselier in
fcd549a7d8 which had been reverted due to reasons lost at this point.
I also added the macro to a few more types. Reviving this patch was
prompted by the discussion on https://llvm.org/D133425.
Differential Revision: https://reviews.llvm.org/D133535
Since those features are general properties of the environment, it makes
sense to use them from libc++abi too, and so the name libcpp-has-no-xxx
doesn't make sense.
Differential Revision: https://reviews.llvm.org/D126482
These can't be made constexpr-constructible (constinit'able),
so they aren't C++20-conforming. Also, the platform versions are
going to be bigger than the atomic/futex version, so we'd have
the awkward situation that `semaphore<42>` could be bigger than
`semaphore<43>`, and that's just silly.
Differential Revision: https://reviews.llvm.org/D110110
Neither the current C++2b draft, nor any revision of [p1135],
nor libstdc++, claims that `counting_semaphore` should be
default-constructible. I think this was just a copy-paste issue
somehow.
Also, `explicit` was missing from the constructor.
Also, `constexpr` remains missing; but that's probably more of a
technical limitation, since apparently there are some platforms
where we don't (can't??) use the atomic implementation and
have to rely on pthreads, which obviously isn't constexpr.
Differential Revision: https://reviews.llvm.org/D110042
Louis Dionne