sanitizer_allocator.cc revision 46f9395baf65e17f1a3f7a3a1deee72a1560ac53 
1//===-- sanitizer_allocator.cc --------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file is shared between AddressSanitizer and ThreadSanitizer
11// run-time libraries.
12// This allocator that is used inside run-times.
13//===----------------------------------------------------------------------===//
14#include "sanitizer_common.h"
15
16// FIXME: We should probably use more low-level allocator that would
17// mmap some pages and split them into chunks to fulfill requests.
18#if SANITIZER_LINUX && !SANITIZER_ANDROID
19extern "C" void *__libc_malloc(__sanitizer::uptr size);
20extern "C" void __libc_free(void *ptr);
21# define LIBC_MALLOC __libc_malloc
22# define LIBC_FREE __libc_free
23#else  // SANITIZER_LINUX && !SANITIZER_ANDROID
24# include <stdlib.h>
25# define LIBC_MALLOC malloc
26# define LIBC_FREE free
27#endif  // SANITIZER_LINUX && !SANITIZER_ANDROID
28
29namespace __sanitizer {
30
31const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
32
33void *InternalAlloc(uptr size) {
34  if (size + sizeof(u64) < size)
35    return 0;
36  void *p = LIBC_MALLOC(size + sizeof(u64));
37  if (p == 0)
38    return 0;
39  ((u64*)p)[0] = kBlockMagic;
40  return (char*)p + sizeof(u64);
41}
42
43void InternalFree(void *addr) {
44  if (addr == 0)
45    return;
46  addr = (char*)addr - sizeof(u64);
47  CHECK_EQ(((u64*)addr)[0], kBlockMagic);
48  ((u64*)addr)[0] = 0;
49  LIBC_FREE(addr);
50}
51
52// LowLevelAllocator
53static LowLevelAllocateCallback low_level_alloc_callback;
54
55void *LowLevelAllocator::Allocate(uptr size) {
56  // Align allocation size.
57  size = RoundUpTo(size, 8);
58  if (allocated_end_ - allocated_current_ < (sptr)size) {
59    uptr size_to_allocate = Max(size, GetPageSizeCached());
60    allocated_current_ =
61        (char*)MmapOrDie(size_to_allocate, __FUNCTION__);
62    allocated_end_ = allocated_current_ + size_to_allocate;
63    if (low_level_alloc_callback) {
64      low_level_alloc_callback((uptr)allocated_current_,
65                               size_to_allocate);
66    }
67  }
68  CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
69  void *res = allocated_current_;
70  allocated_current_ += size;
71  return res;
72}
73
74void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
75  low_level_alloc_callback = callback;
76}
77
78bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
79  if (!size) return false;
80  uptr max = (uptr)-1L;
81  return (max / size) < n;
82}
83
84}  // namespace __sanitizer
85