libcxx/include/__memory/addressof.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___MEMORY_ADDRESSOF_H
  11 #define _LIBCPP___MEMORY_ADDRESSOF_H
  12
  13 #include <__config>
  14
  15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  16 #pragma GCC system_header
  17 #endif
  18
  19 _LIBCPP_BEGIN_NAMESPACE_STD
  20
  21 template <class _Tp>
  22 inline _LIBCPP_CONSTEXPR_AFTER_CXX14
  23 _LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
  24 _Tp*
  25 addressof(_Tp& __x) _NOEXCEPT
  26 {
  27     return __builtin_addressof(__x);
  28 }
  29
  30 #if defined(_LIBCPP_HAS_OBJC_ARC) && !defined(_LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF)
  31 // Objective-C++ Automatic Reference Counting uses qualified pointers
  32 // that require special addressof() signatures. When
  33 // _LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF is defined, the compiler
  34 // itself is providing these definitions. Otherwise, we provide them.
  35 template <class _Tp>
  36 inline _LIBCPP_INLINE_VISIBILITY
  37 __strong _Tp*
  38 addressof(__strong _Tp& __x) _NOEXCEPT
  39 {
  40   return &__x;
  41 }
  42
  43 #ifdef _LIBCPP_HAS_OBJC_ARC_WEAK
  44 template <class _Tp>
  45 inline _LIBCPP_INLINE_VISIBILITY
  46 __weak _Tp*
  47 addressof(__weak _Tp& __x) _NOEXCEPT
  48 {
  49   return &__x;
  50 }
  51 #endif
  52
  53 template <class _Tp>
  54 inline _LIBCPP_INLINE_VISIBILITY
  55 __autoreleasing _Tp*
  56 addressof(__autoreleasing _Tp& __x) _NOEXCEPT
  57 {
  58   return &__x;
  59 }
  60
  61 template <class _Tp>
  62 inline _LIBCPP_INLINE_VISIBILITY
  63 __unsafe_unretained _Tp*
  64 addressof(__unsafe_unretained _Tp& __x) _NOEXCEPT
  65 {
  66   return &__x;
  67 }
  68 #endif
  69
  70 #if !defined(_LIBCPP_CXX03_LANG)
  71 template <class _Tp> _Tp* addressof(const _Tp&&) noexcept = delete;
  72 #endif
  73
  74 _LIBCPP_END_NAMESPACE_STD
  75
  76 #endif // _LIBCPP___MEMORY_ADDRESSOF_H