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 <bits/exception_defines.h> 29 #include "new" 30 31 using std::new_handler; 32 using std::bad_alloc; 33 34 #if !_GLIBCXX_HAVE_ALIGNED_ALLOC 35 #if _GLIBCXX_HAVE__ALIGNED_MALLOC 36 #define aligned_alloc(al,sz) _aligned_malloc(sz,al) 37 #elif _GLIBCXX_HAVE_POSIX_MEMALIGN 38 static inline void* 39 aligned_alloc (std::size_t al, std::size_t sz) 40 { 41 void *ptr; 42 // The value of alignment shall be a power of two multiple of sizeof(void *). 43 if (al < sizeof(void*)) 44 al = sizeof(void*); 45 int ret = posix_memalign (&ptr, al, sz); 46 if (ret == 0) 47 return ptr; 48 return nullptr; 49 } 50 #elif _GLIBCXX_HAVE_MEMALIGN 51 #if _GLIBCXX_HOSTED 52 #include <malloc.h> 53 #else 54 extern "C" void *memalign(std::size_t boundary, std::size_t size); 55 #endif 56 #define aligned_alloc memalign 57 #else 58 #include <stdint.h> 59 // The C library doesn't provide any aligned allocation functions, define one. 60 // This is a modified version of code from gcc/config/i386/gmm_malloc.h 61 static inline void* 62 aligned_alloc (std::size_t al, std::size_t sz) 63 { 64 // Alignment must be a power of two. 65 if (al & (al - 1)) 66 return nullptr; 67 else if (!sz) 68 return nullptr; 69 70 // We need extra bytes to store the original value returned by malloc. 71 if (al < sizeof(void*)) 72 al = sizeof(void*); 73 void* const malloc_ptr = malloc(sz + al); 74 if (!malloc_ptr) 75 return nullptr; 76 // Align to the requested value, leaving room for the original malloc value. 77 void* const aligned_ptr = (void *) (((uintptr_t) malloc_ptr + al) & -al); 78 79 // Store the original malloc value where it can be found by operator delete. 80 ((void **) aligned_ptr)[-1] = malloc_ptr; 81 82 return aligned_ptr; 83 } 84 #endif 85 #endif 86 87 _GLIBCXX_WEAK_DEFINITION void * 88 operator new (std::size_t sz, std::align_val_t al) 89 { 90 void *p; 91 std::size_t align = (std::size_t)al; 92 93 /* malloc (0) is unpredictable; avoid it. */ 94 if (sz == 0) 95 sz = 1; 96 97 #if _GLIBCXX_HAVE_ALIGNED_ALLOC 98 /* C11: the value of size shall be an integral multiple of alignment. */ 99 if (std::size_t rem = sz & (align - 1)) 100 sz += align - rem; 101 #endif 102 103 while (__builtin_expect ((p = aligned_alloc (align, sz)) == 0, false)) 104 { 105 new_handler handler = std::get_new_handler (); 106 if (! handler) 107 _GLIBCXX_THROW_OR_ABORT(bad_alloc()); 108 handler (); 109 } 110 111 return p; 112 } 113