b9a2658a3e
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.
60 lines
1.6 KiB
C++
60 lines
1.6 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_CSTDALIGN
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#define _LIBCPP_CSTDALIGN
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/*
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cstdalign synopsis
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Macros:
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__alignas_is_defined
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__alignof_is_defined
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*/
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#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
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# include <__cxx03/__config>
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#else
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# include <__config>
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// <stdalign.h> is not provided by libc++
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# if __has_include(<stdalign.h>)
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# include <stdalign.h>
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# ifdef _LIBCPP_STDALIGN_H
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# error "If libc++ starts defining <stdalign.h>, the __has_include check should move to libc++'s <stdalign.h>"
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# endif
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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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# undef __alignas_is_defined
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# define __alignas_is_defined 1
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# undef __alignof_is_defined
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# define __alignof_is_defined 1
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# if _LIBCPP_STD_VER >= 20
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using __standard_header_cstdalign _LIBCPP_DEPRECATED_("removed in C++20.") = void;
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using __use_standard_header_cstdalign = __standard_header_cstdalign;
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# elif _LIBCPP_STD_VER >= 17
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using __standard_header_cstdalign _LIBCPP_DEPRECATED = void;
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using __use_standard_header_cstdalign = __standard_header_cstdalign;
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# endif
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#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
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#endif // _LIBCPP_CSTDALIGN
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