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8cedff10a1
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
147 lines
4.1 KiB
C++
147 lines
4.1 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP_CSTDDEF
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#define _LIBCPP_CSTDDEF
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/*
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cstddef synopsis
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Macros:
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offsetof(type,member-designator)
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NULL
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namespace std
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{
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Types:
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ptrdiff_t
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size_t
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max_align_t // C++11
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nullptr_t
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byte // C++17
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} // std
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*/
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#include <__assert> // all public C++ headers provide the assertion handler
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#include <__config>
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#include <__type_traits/enable_if.h>
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#include <__type_traits/integral_constant.h>
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#include <__type_traits/is_integral.h>
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#include <version>
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#include <stddef.h>
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#ifndef _LIBCPP_STDDEF_H
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# error <cstddef> tried including <stddef.h> but didn't find libc++'s <stddef.h> header. \
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This usually means that your header search paths are not configured properly. \
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The header search paths should contain the C++ Standard Library headers before \
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any C Standard Library, and you are probably using compiler flags that make that \
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not be the case.
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#endif
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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using ::nullptr_t;
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using ::ptrdiff_t _LIBCPP_USING_IF_EXISTS;
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using ::size_t _LIBCPP_USING_IF_EXISTS;
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#if !defined(_LIBCPP_CXX03_LANG)
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using ::max_align_t _LIBCPP_USING_IF_EXISTS;
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#endif
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_LIBCPP_END_NAMESPACE_STD
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#if _LIBCPP_STD_VER > 14
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namespace std // purposefully not versioned
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{
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enum class byte : unsigned char {};
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_LIBCPP_HIDE_FROM_ABI constexpr byte operator| (byte __lhs, byte __rhs) noexcept
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{
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return static_cast<byte>(
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static_cast<unsigned char>(
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static_cast<unsigned int>(__lhs) | static_cast<unsigned int>(__rhs)
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));
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}
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_LIBCPP_HIDE_FROM_ABI constexpr byte& operator|=(byte& __lhs, byte __rhs) noexcept
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{ return __lhs = __lhs | __rhs; }
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_LIBCPP_HIDE_FROM_ABI constexpr byte operator& (byte __lhs, byte __rhs) noexcept
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{
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return static_cast<byte>(
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static_cast<unsigned char>(
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static_cast<unsigned int>(__lhs) & static_cast<unsigned int>(__rhs)
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));
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}
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_LIBCPP_HIDE_FROM_ABI constexpr byte& operator&=(byte& __lhs, byte __rhs) noexcept
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{ return __lhs = __lhs & __rhs; }
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_LIBCPP_HIDE_FROM_ABI constexpr byte operator^ (byte __lhs, byte __rhs) noexcept
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{
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return static_cast<byte>(
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static_cast<unsigned char>(
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static_cast<unsigned int>(__lhs) ^ static_cast<unsigned int>(__rhs)
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));
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}
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_LIBCPP_HIDE_FROM_ABI constexpr byte& operator^=(byte& __lhs, byte __rhs) noexcept
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{ return __lhs = __lhs ^ __rhs; }
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_LIBCPP_HIDE_FROM_ABI constexpr byte operator~ (byte __b) noexcept
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{
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return static_cast<byte>(
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static_cast<unsigned char>(
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~static_cast<unsigned int>(__b)
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));
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}
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template <class _Tp>
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using _EnableByteOverload = __enable_if_t<is_integral<_Tp>::value, byte>;
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template <class _Integer>
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_LIBCPP_HIDE_FROM_ABI constexpr _EnableByteOverload<_Integer> &
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operator<<=(byte& __lhs, _Integer __shift) noexcept
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{ return __lhs = __lhs << __shift; }
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template <class _Integer>
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_LIBCPP_HIDE_FROM_ABI constexpr _EnableByteOverload<_Integer>
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operator<< (byte __lhs, _Integer __shift) noexcept
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{ return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) << __shift)); }
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template <class _Integer>
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_LIBCPP_HIDE_FROM_ABI constexpr _EnableByteOverload<_Integer> &
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operator>>=(byte& __lhs, _Integer __shift) noexcept
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{ return __lhs = __lhs >> __shift; }
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template <class _Integer>
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_LIBCPP_HIDE_FROM_ABI constexpr _EnableByteOverload<_Integer>
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operator>> (byte __lhs, _Integer __shift) noexcept
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{ return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) >> __shift)); }
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template <class _Integer, class = _EnableByteOverload<_Integer> >
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_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr _Integer
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to_integer(byte __b) noexcept { return static_cast<_Integer>(__b); }
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} // namespace std
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#endif
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#endif // _LIBCPP_CSTDDEF
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