1// Support routines for the -*- C++ -*- dynamic memory management.
2
3// Copyright (C) 1997-2017 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
31using std::new_handler;
32using 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
38static inline void*
39aligned_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
54extern "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
61static inline void*
62aligned_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 *
88operator 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