This patch implements the forwarding to frozen C++03 headers as discussed in https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc. In the RFC, we initially proposed selecting the right headers from the Clang driver, however consensus seemed to steer towards handling this in the library itself. This patch implements that direction. At a high level, the changes basically amount to making each public header look like this: ``` // inside <vector> #ifdef _LIBCPP_CXX03_LANG # include <__cxx03/vector> #else // normal <vector> content #endif ``` In most cases, public headers are simple umbrella headers so there isn't much code in the #else branch. In other cases, the #else branch contains the actual implementation of the header.
Including The frozen C++03 headers results in a lot of formatting changes in the main headers, so this splits these changes into a separate commit instead. This is part of https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc.
Many headers include `<cstddef>` just for size_t, and pulling in additional content (e.g. the traits used for std::byte) is unnecessary. To solve this problem, this patch splits up `<cstddef>` into subcomponents so that headers can include only the parts that they actually require. This has the added benefit of making the modules build a lot stricter with respect to IWYU, and also providing a canonical location where we define `std::size_t` and friends (which were previously defined in multiple headers like `<cstddef>` and `<ctime>`). After this patch, there's still many places in the codebase where we include `<cstddef>` when `<__cstddef/size_t.h>` would be sufficient. This patch focuses on removing `<cstddef>` includes from __type_traits to make these headers non-circular with `<cstddef>`. Additional refactorings can be tackled separately.
Originally, we used __libcpp_verbose_abort to handle assertion failures. That function was declared from all public headers. Since we don't use that mechanism anymore, we don't need to declare __libcpp_verbose_abort from all public headers, and we can clean up a lot of unnecessary includes. This patch also moves the definition of the various assertion categories to the <__assert> header, since we now rely on regular IWYU for these assertion macros. rdar://105510916
Reviewed By: ldionne, Mordante, #libc, #libc_abi Spies: libcxx-commits Differential Revision: https://reviews.llvm.org/D143329
This allows us to reuse workarounds for compilers that don't provide the builtins or constexpr support. Reviewed By: ldionne, Mordante, #libc Spies: libcxx-commits Differential Revision: https://reviews.llvm.org/D139555
An issue I often see in codebases compiled for unusual platforms is that header search paths are specified manually and are subtly wrong. For example, people will manually add `-isystem <some-toolchain>/usr/include`, which ends up messing up the layering of header search paths required by libc++ (because the C Standard Library now appears *before* libc++ in the search paths). Without this patch, this will end up causing compilation errors that are pretty inscrutable. This patch aims to improve the user experience by diagnosing this issue explicitly. In all cases I can think of, I would expect that a compilation error occur if these header search paths are not layered properly. This should only provide an explicit diagnostic instead of failing due to seemingly unrelated compilation errors. Differential Revision: https://reviews.llvm.org/D131441
This patch changes the requirement for getting the declaration of the assertion handler from including <__assert> to including any public C++ header of the library. Note that C compatibility headers are excluded because we don't implement all the C headers ourselves -- some of them are taken straight from the C library, like assert.h. It also adds a generated test to check it. Furthermore, this new generated test is designed in a way that will make it possible to replace almost all the existing test-generation scripts with this system in upcoming patches. Differential Revision: https://reviews.llvm.org/D122506
Now we'll notice if a header forgets to include this magic phrase. Differential Revision: https://reviews.llvm.org/D118800
We've stopped doing it in libc++ for a while now because these names would end up rotting as we move things around and copy/paste stuff. This cleans up all the existing files so as to stop the spreading as people copy-paste headers around.