1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___TYPE_TRAITS_ALIGNED_STORAGE_H 10 #define _LIBCPP___TYPE_TRAITS_ALIGNED_STORAGE_H 11 12 #include <__config> 13 #include <__type_traits/conditional.h> 14 #include <__type_traits/integral_constant.h> 15 #include <__type_traits/nat.h> 16 #include <__type_traits/type_list.h> 17 #include <cstddef> 18 19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 20 # pragma GCC system_header 21 #endif 22 23 _LIBCPP_BEGIN_NAMESPACE_STD 24 25 template <class _Tp> 26 struct __align_type 27 { 28 static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp); 29 typedef _Tp type; 30 }; 31 32 struct __struct_double {long double __lx;}; 33 struct __struct_double4 {double __lx[4];}; 34 35 typedef 36 __type_list<__align_type<unsigned char>, 37 __type_list<__align_type<unsigned short>, 38 __type_list<__align_type<unsigned int>, 39 __type_list<__align_type<unsigned long>, 40 __type_list<__align_type<unsigned long long>, 41 __type_list<__align_type<double>, 42 __type_list<__align_type<long double>, 43 __type_list<__align_type<__struct_double>, 44 __type_list<__align_type<__struct_double4>, 45 __type_list<__align_type<int*>, 46 __nat 47 > > > > > > > > > > __all_types; 48 49 template <size_t _Align> 50 struct _ALIGNAS(_Align) __fallback_overaligned {}; 51 52 template <class _TL, size_t _Align> struct __find_pod; 53 54 template <class _Hp, size_t _Align> 55 struct __find_pod<__type_list<_Hp, __nat>, _Align> 56 { 57 typedef __conditional_t<_Align == _Hp::value, typename _Hp::type, __fallback_overaligned<_Align> > type; 58 }; 59 60 template <class _Hp, class _Tp, size_t _Align> 61 struct __find_pod<__type_list<_Hp, _Tp>, _Align> 62 { 63 typedef __conditional_t<_Align == _Hp::value, typename _Hp::type, typename __find_pod<_Tp, _Align>::type> type; 64 }; 65 66 template <class _TL, size_t _Len> struct __find_max_align; 67 68 template <class _Hp, size_t _Len> 69 struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {}; 70 71 template <size_t _Len, size_t _A1, size_t _A2> 72 struct __select_align 73 { 74 private: 75 static const size_t __min = _A2 < _A1 ? _A2 : _A1; 76 static const size_t __max = _A1 < _A2 ? _A2 : _A1; 77 public: 78 static const size_t value = _Len < __max ? __min : __max; 79 }; 80 81 template <class _Hp, class _Tp, size_t _Len> 82 struct __find_max_align<__type_list<_Hp, _Tp>, _Len> 83 : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {}; 84 85 template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value> 86 struct _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_TEMPLATE_VIS aligned_storage 87 { 88 typedef typename __find_pod<__all_types, _Align>::type _Aligner; 89 union type 90 { 91 _Aligner __align; 92 unsigned char __data[(_Len + _Align - 1)/_Align * _Align]; 93 }; 94 }; 95 96 #if _LIBCPP_STD_VER > 11 97 98 _LIBCPP_SUPPRESS_DEPRECATED_PUSH 99 template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value> 100 using aligned_storage_t _LIBCPP_DEPRECATED_IN_CXX23 = typename aligned_storage<_Len, _Align>::type; 101 _LIBCPP_SUPPRESS_DEPRECATED_POP 102 103 #endif 104 105 #define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \ 106 template <size_t _Len>\ 107 struct _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\ 108 {\ 109 struct _ALIGNAS(n) type\ 110 {\ 111 unsigned char __lx[(_Len + n - 1)/n * n];\ 112 };\ 113 } 114 115 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1); 116 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2); 117 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4); 118 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8); 119 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10); 120 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20); 121 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40); 122 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80); 123 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100); 124 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200); 125 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400); 126 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800); 127 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000); 128 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000); 129 // PE/COFF does not support alignment beyond 8192 (=0x2000) 130 #if !defined(_LIBCPP_OBJECT_FORMAT_COFF) 131 _CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000); 132 #endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF) 133 134 #undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION 135 136 _LIBCPP_END_NAMESPACE_STD 137 138 #endif // _LIBCPP___TYPE_TRAITS_ALIGNED_STORAGE_H 139