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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.
102 lines
2.7 KiB
C++
102 lines
2.7 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_BIT
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#define _LIBCPP_BIT
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/*
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bit synopsis
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namespace std {
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// [bit.cast], bit_cast
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template<class To, class From>
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constexpr To bit_cast(const From& from) noexcept; // C++20
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// [bit.byteswap], byteswap
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template<class T>
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constexpr T byteswap(T value) noexcept; // C++23
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// [bit.pow.two], integral powers of 2
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template <class T>
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constexpr bool has_single_bit(T x) noexcept; // C++20
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template <class T>
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constexpr T bit_ceil(T x); // C++20
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template <class T>
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constexpr T bit_floor(T x) noexcept; // C++20
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template <class T>
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constexpr int bit_width(T x) noexcept; // C++20
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// [bit.rotate], rotating
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template<class T>
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constexpr T rotl(T x, int s) noexcept; // C++20
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template<class T>
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constexpr T rotr(T x, int s) noexcept; // C++20
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// [bit.count], counting
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template<class T>
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constexpr int countl_zero(T x) noexcept; // C++20
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template<class T>
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constexpr int countl_one(T x) noexcept; // C++20
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template<class T>
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constexpr int countr_zero(T x) noexcept; // C++20
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template<class T>
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constexpr int countr_one(T x) noexcept; // C++20
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template<class T>
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constexpr int popcount(T x) noexcept; // C++20
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// [bit.endian], endian
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enum class endian {
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little = see below, // C++20
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big = see below, // C++20
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native = see below // C++20
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};
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} // namespace std
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*/
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#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
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# include <__cxx03/bit>
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#else
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# include <__config>
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# if _LIBCPP_STD_VER >= 20
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# include <__bit/bit_cast.h>
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# include <__bit/bit_ceil.h>
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# include <__bit/bit_floor.h>
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# include <__bit/bit_log2.h>
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# include <__bit/bit_width.h>
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# include <__bit/countl.h>
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# include <__bit/countr.h>
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# include <__bit/endian.h>
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# include <__bit/has_single_bit.h>
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# include <__bit/popcount.h>
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# include <__bit/rotate.h>
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# endif
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# if _LIBCPP_STD_VER >= 23
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# include <__bit/byteswap.h>
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# endif
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# include <version>
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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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# if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
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# include <cstdlib>
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# include <iosfwd>
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# include <limits>
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# include <type_traits>
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# endif
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#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
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#endif // _LIBCPP_BIT
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