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111
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1 // Support routines for the -*- C++ -*- dynamic memory management.
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2
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145
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3 // Copyright (C) 1997-2020 Free Software Foundation, Inc.
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111
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4 //
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5 // This file is part of GCC.
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6 //
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7 // GCC is free software; you can redistribute it and/or modify
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8 // it under the terms of the GNU General Public License as published by
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9 // the Free Software Foundation; either version 3, or (at your option)
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10 // any later version.
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11 //
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12 // GCC is distributed in the hope that it will be useful,
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13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 // GNU General Public License for more details.
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16 //
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17 // Under Section 7 of GPL version 3, you are granted additional
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18 // permissions described in the GCC Runtime Library Exception, version
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19 // 3.1, as published by the Free Software Foundation.
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20
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21 // You should have received a copy of the GNU General Public License and
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22 // a copy of the GCC Runtime Library Exception along with this program;
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23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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24 // <http://www.gnu.org/licenses/>.
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25
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26 #include <bits/c++config.h>
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27 #include <stdlib.h>
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131
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28 #include <stdint.h>
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111
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29 #include <bits/exception_defines.h>
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131
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30 #include <bit>
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111
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31 #include "new"
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32
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131
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33 #if !_GLIBCXX_HAVE_ALIGNED_ALLOC && !_GLIBCXX_HAVE__ALIGNED_MALLOC \
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34 && !_GLIBCXX_HAVE_POSIX_MEMALIGN && _GLIBCXX_HAVE_MEMALIGN
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35 # if _GLIBCXX_HOSTED && __has_include(<malloc.h>)
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36 // Some C libraries declare memalign in <malloc.h>
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37 # include <malloc.h>
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38 # else
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39 extern "C" void *memalign(std::size_t boundary, std::size_t size);
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40 # endif
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41 #endif
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42
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43 using std::new_handler;
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44 using std::bad_alloc;
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45
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46 #if ! _GLIBCXX_HOSTED
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47 extern "C"
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48 {
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49 # if _GLIBCXX_HAVE_ALIGNED_ALLOC
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50 void *aligned_alloc(size_t alignment, size_t size);
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51 # elif _GLIBCXX_HAVE__ALIGNED_MALLOC
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52 void *_aligned_malloc(size_t size, size_t alignment);
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53 # elif _GLIBCXX_HAVE_POSIX_MEMALIGN
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54 void *posix_memalign(void **, size_t alignment, size_t size);
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55 # elif _GLIBCXX_HAVE_MEMALIGN
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56 void *memalign(size_t alignment, size_t size);
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57 # endif
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58 }
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59 #endif
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60
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131
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61 namespace __gnu_cxx {
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62 #if _GLIBCXX_HAVE_ALIGNED_ALLOC
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63 using ::aligned_alloc;
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64 #elif _GLIBCXX_HAVE__ALIGNED_MALLOC
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65 static inline void*
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66 aligned_alloc (std::size_t al, std::size_t sz)
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67 { return _aligned_malloc(sz, al); }
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68 #elif _GLIBCXX_HAVE_POSIX_MEMALIGN
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69 static inline void*
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70 aligned_alloc (std::size_t al, std::size_t sz)
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71 {
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72 void *ptr;
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131
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73 // posix_memalign has additional requirement, not present on aligned_alloc:
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74 // The value of alignment shall be a power of two multiple of sizeof(void *).
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75 if (al < sizeof(void*))
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76 al = sizeof(void*);
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77 int ret = posix_memalign (&ptr, al, sz);
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78 if (ret == 0)
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79 return ptr;
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80 return nullptr;
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81 }
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82 #elif _GLIBCXX_HAVE_MEMALIGN
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131
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83 static inline void*
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84 aligned_alloc (std::size_t al, std::size_t sz)
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85 {
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86 return memalign (al, sz);
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87 }
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88 #else // !HAVE__ALIGNED_MALLOC && !HAVE_POSIX_MEMALIGN && !HAVE_MEMALIGN
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111
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89 // The C library doesn't provide any aligned allocation functions, define one.
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90 // This is a modified version of code from gcc/config/i386/gmm_malloc.h
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91 static inline void*
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92 aligned_alloc (std::size_t al, std::size_t sz)
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93 {
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94 // We need extra bytes to store the original value returned by malloc.
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95 if (al < sizeof(void*))
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96 al = sizeof(void*);
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97 void* const malloc_ptr = malloc(sz + al);
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98 if (!malloc_ptr)
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99 return nullptr;
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100 // Align to the requested value, leaving room for the original malloc value.
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101 void* const aligned_ptr = (void *) (((uintptr_t) malloc_ptr + al) & -al);
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102
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103 // Store the original malloc value where it can be found by operator delete.
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104 ((void **) aligned_ptr)[-1] = malloc_ptr;
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105
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106 return aligned_ptr;
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107 }
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108 #endif
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131
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109 } // namespace __gnu_cxx
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111
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110
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111 _GLIBCXX_WEAK_DEFINITION void *
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112 operator new (std::size_t sz, std::align_val_t al)
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113 {
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114 std::size_t align = (std::size_t)al;
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115
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131
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116 /* Alignment must be a power of two. */
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117 /* XXX This should be checked by the compiler (PR 86878). */
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118 if (__builtin_expect (!std::__ispow2(align), false))
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119 _GLIBCXX_THROW_OR_ABORT(bad_alloc());
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120
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111
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121 /* malloc (0) is unpredictable; avoid it. */
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131
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122 if (__builtin_expect (sz == 0, false))
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123 sz = 1;
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124
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125 #if _GLIBCXX_HAVE_ALIGNED_ALLOC
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145
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126 # if defined _AIX || defined __APPLE__
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131
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127 /* AIX 7.2.0.0 aligned_alloc incorrectly has posix_memalign's requirement
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128 * that alignment is a multiple of sizeof(void*).
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129 * OS X 10.15 has the same requirement. */
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131
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130 if (align < sizeof(void*))
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131 align = sizeof(void*);
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132 # endif
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111
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133 /* C11: the value of size shall be an integral multiple of alignment. */
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131
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134 sz = (sz + align - 1) & ~(align - 1);
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135 #endif
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136
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137 void *p;
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138
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139 while ((p = __gnu_cxx::aligned_alloc (align, sz)) == nullptr)
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111
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140 {
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141 new_handler handler = std::get_new_handler ();
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142 if (! handler)
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143 _GLIBCXX_THROW_OR_ABORT(bad_alloc());
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144 handler ();
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145 }
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146
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147 return p;
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148 }
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