1 // Support routines for the -*- C++ -*- dynamic memory management. 2 3 // Copyright (C) 1997-2018 Free Software Foundation, Inc. 4 // 5 // This file is part of GCC. 6 // 7 // GCC is free software; you can redistribute it and/or modify 8 // it under the terms of the GNU General Public License as published by 9 // the Free Software Foundation; either version 3, or (at your option) 10 // any later version. 11 // 12 // GCC is distributed in the hope that it will be useful, 13 // but WITHOUT ANY WARRANTY; without even the implied warranty of 14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 // GNU General Public License for more details. 16 // 17 // Under Section 7 of GPL version 3, you are granted additional 18 // permissions described in the GCC Runtime Library Exception, version 19 // 3.1, as published by the Free Software Foundation. 20 21 // You should have received a copy of the GNU General Public License and 22 // a copy of the GCC Runtime Library Exception along with this program; 23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 // <http://www.gnu.org/licenses/>. 25 26 #include <bits/c++config.h> 27 #include <stdlib.h> 28 #include <stdint.h> 29 #include <bits/exception_defines.h> 30 #include "new" 31 32 #if !_GLIBCXX_HAVE_ALIGNED_ALLOC && !_GLIBCXX_HAVE__ALIGNED_MALLOC \ 33 && !_GLIBCXX_HAVE_POSIX_MEMALIGN && _GLIBCXX_HAVE_MEMALIGN 34 # if _GLIBCXX_HOSTED && __has_include(<malloc.h>) 35 // Some C libraries declare memalign in <malloc.h> 36 # include <malloc.h> 37 # else 38 extern "C" void *memalign(std::size_t boundary, std::size_t size); 39 # endif 40 #endif 41 42 using std::new_handler; 43 using std::bad_alloc; 44 45 #if ! _GLIBCXX_HOSTED 46 extern "C" 47 { 48 # if _GLIBCXX_HAVE_ALIGNED_ALLOC 49 void *aligned_alloc(size_t alignment, size_t size); 50 # elif _GLIBCXX_HAVE__ALIGNED_MALLOC 51 void *_aligned_malloc(size_t size, size_t alignment); 52 # elif _GLIBCXX_HAVE_POSIX_MEMALIGN 53 void *posix_memalign(void **, size_t alignment, size_t size); 54 # elif _GLIBCXX_HAVE_MEMALIGN 55 void *memalign(size_t alignment, size_t size); 56 # endif 57 } 58 #endif 59 60 namespace __gnu_cxx { 61 #if _GLIBCXX_HAVE_ALIGNED_ALLOC 62 using ::aligned_alloc; 63 #elif _GLIBCXX_HAVE__ALIGNED_MALLOC 64 static inline void* 65 aligned_alloc (std::size_t al, std::size_t sz) 66 { return _aligned_malloc(sz, al); } 67 #elif _GLIBCXX_HAVE_POSIX_MEMALIGN 68 static inline void* 69 aligned_alloc (std::size_t al, std::size_t sz) 70 { 71 void *ptr; 72 // posix_memalign has additional requirement, not present on aligned_alloc: 73 // The value of alignment shall be a power of two multiple of sizeof(void *). 74 if (al < sizeof(void*)) 75 al = sizeof(void*); 76 int ret = posix_memalign (&ptr, al, sz); 77 if (ret == 0) 78 return ptr; 79 return nullptr; 80 } 81 #elif _GLIBCXX_HAVE_MEMALIGN 82 static inline void* 83 aligned_alloc (std::size_t al, std::size_t sz) 84 { 85 #ifdef __sun 86 // Solaris 10 memalign requires that alignment is greater than or equal to 87 // the size of a word. 88 if (al < sizeof(int)) 89 al = sizeof(int); 90 #endif 91 return memalign (al, sz); 92 } 93 #else // !HAVE__ALIGNED_MALLOC && !HAVE_POSIX_MEMALIGN && !HAVE_MEMALIGN 94 // The C library doesn't provide any aligned allocation functions, define one. 95 // This is a modified version of code from gcc/config/i386/gmm_malloc.h 96 static inline void* 97 aligned_alloc (std::size_t al, std::size_t sz) 98 { 99 // We need extra bytes to store the original value returned by malloc. 100 if (al < sizeof(void*)) 101 al = sizeof(void*); 102 void* const malloc_ptr = malloc(sz + al); 103 if (!malloc_ptr) 104 return nullptr; 105 // Align to the requested value, leaving room for the original malloc value. 106 void* const aligned_ptr = (void *) (((uintptr_t) malloc_ptr + al) & -al); 107 108 // Store the original malloc value where it can be found by operator delete. 109 ((void **) aligned_ptr)[-1] = malloc_ptr; 110 111 return aligned_ptr; 112 } 113 #endif 114 } // namespace __gnu_cxx 115 116 _GLIBCXX_WEAK_DEFINITION void * 117 operator new (std::size_t sz, std::align_val_t al) 118 { 119 void *p; 120 std::size_t align = (std::size_t)al; 121 122 /* Alignment must be a power of two. */ 123 /* XXX This should be checked by the compiler (PR 86878). */ 124 if (__builtin_expect (align & (align - 1), false)) 125 _GLIBCXX_THROW_OR_ABORT(bad_alloc()); 126 127 /* malloc (0) is unpredictable; avoid it. */ 128 if (__builtin_expect (sz == 0, false)) 129 sz = 1; 130 131 #if _GLIBCXX_HAVE_ALIGNED_ALLOC 132 # if defined _AIX || defined __APPLE__ 133 /* AIX 7.2.0.0 aligned_alloc incorrectly has posix_memalign's requirement 134 * that alignment is a multiple of sizeof(void*). 135 * OS X 10.15 has the same requirement. */ 136 if (align < sizeof(void*)) 137 align = sizeof(void*); 138 # endif 139 /* C11: the value of size shall be an integral multiple of alignment. */ 140 if (std::size_t rem = sz & (align - 1)) 141 sz += align - rem; 142 #endif 143 144 using __gnu_cxx::aligned_alloc; 145 while (__builtin_expect ((p = aligned_alloc (align, sz)) == 0, false)) 146 { 147 new_handler handler = std::get_new_handler (); 148 if (! handler) 149 _GLIBCXX_THROW_OR_ABORT(bad_alloc()); 150 handler (); 151 } 152 153 return p; 154 } 155