The synchronization library was marked as disabled on Apple platforms
up to now because we were not 100% sure that it was going to be ABI
stable. However, it's been some time since we shipped it in upstream
libc++ now and there's been no changes so far. This patch enables the
synchronization library on Apple platforms, and hence commits the ABI
stability as far as that vendor is concerned.
Differential Revision: https://reviews.llvm.org/D96790
This prevents std::format to be available until there's an ABI stable
version. (This only impacts the Apple platform.)
Depends on D102703
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D102705
Before this patch, feature-test macros didn't take special availability
markup into account, which means that feature-test macros can sometimes
appear to "lie". For example, if you compile in C++20 mode and target
macOS 10.13, the __cpp_lib_filesystem feature-test macro will be provided
even though the <filesystem> declarations are marked as unavailable.
This patch fixes that.
rdar://68142369
Differential Revision: https://reviews.llvm.org/D94983
Currently, vendor-specific availability markup is enabled by default.
This means that even when building against trunk libc++, the headers
will by default prevent you from using some features that were not
released in the dylib on your target platform. This is a source of
frustration since people building libc++ from sources are usually not
trying to use some vendor's released dylib.
For that reason, I've been thinking for a long time that availability
annotations should be off by default, which is the primary change that
this commit enables.
In addition, it reworks the implementation to make it easier for new
vendors to add availability annotations for their platform, and it
refreshes the documentation to reflect the current state of the codebase.
Finally, a CMake configuration option is added to control whether
availability annotations should be turned on for the flavor of libc++
being created. The intent is for vendors like Apple to turn it on, and
for the upstream libc++ to leave it off (the default).
Differential Revision: https://reviews.llvm.org/D90843
Louis Dionne