mirror of
https://github.com/llvm/llvm-project.git
synced 2025-04-25 04:06:06 +00:00

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.