msan_allocator.cc revision 13c379073b8af7eb5ea4706078428d1594c487ab 
1//===-- msan_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 a part of MemorySanitizer.
11//
12// MemorySanitizer allocator.
13//===----------------------------------------------------------------------===//
14
15#include "sanitizer_common/sanitizer_allocator.h"
16#include "sanitizer_common/sanitizer_stackdepot.h"
17#include "msan.h"
18
19namespace __msan {
20
21struct Metadata {
22  uptr requested_size;
23};
24
25static const uptr kAllocatorSpace = 0x600000000000ULL;
26static const uptr kAllocatorSize   = 0x80000000000;  // 8T.
27static const uptr kMetadataSize  = sizeof(Metadata);
28
29typedef SizeClassAllocator64<kAllocatorSpace, kAllocatorSize, kMetadataSize,
30                             DefaultSizeClassMap> PrimaryAllocator;
31typedef SizeClassAllocatorLocalCache<PrimaryAllocator> AllocatorCache;
32typedef LargeMmapAllocator<> SecondaryAllocator;
33typedef CombinedAllocator<PrimaryAllocator, AllocatorCache,
34                          SecondaryAllocator> Allocator;
35
36static THREADLOCAL AllocatorCache cache;
37static Allocator allocator;
38
39static int inited = 0;
40
41static inline void Init() {
42  if (inited) return;
43  __msan_init();
44  inited = true;  // this must happen before any threads are created.
45  allocator.Init();
46}
47
48static void *MsanAllocate(StackTrace *stack, uptr size,
49                          uptr alignment, bool zeroise) {
50  Init();
51  void *res = allocator.Allocate(&cache, size, alignment, false);
52  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(res));
53  meta->requested_size = size;
54  if (zeroise)
55    __msan_clear_and_unpoison(res, size);
56  else if (flags()->poison_in_malloc)
57    __msan_poison(res, size);
58  if (__msan_get_track_origins()) {
59    u32 stack_id = StackDepotPut(stack->trace, stack->size);
60    CHECK(stack_id);
61    CHECK_EQ((stack_id >> 31), 0);  // Higher bit is occupied by stack origins.
62    __msan_set_origin(res, size, stack_id);
63  }
64  MSAN_MALLOC_HOOK(res, size);
65  return res;
66}
67
68void MsanDeallocate(void *p) {
69  CHECK(p);
70  Init();
71  MSAN_FREE_HOOK(p);
72  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(p));
73  uptr size = meta->requested_size;
74  meta->requested_size = 0;
75  // This memory will not be reused by anyone else, so we are free to keep it
76  // poisoned.
77  __msan_poison(p, size);
78  if (__msan_get_track_origins())
79    __msan_set_origin(p, size, -1);
80  allocator.Deallocate(&cache, p);
81}
82
83void *MsanReallocate(StackTrace *stack, void *old_p, uptr new_size,
84                     uptr alignment, bool zeroise) {
85  if (!old_p)
86    return MsanAllocate(stack, new_size, alignment, zeroise);
87  if (!new_size) {
88    MsanDeallocate(old_p);
89    return 0;
90  }
91  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(old_p));
92  uptr old_size = meta->requested_size;
93  uptr actually_allocated_size = allocator.GetActuallyAllocatedSize(old_p);
94  if (new_size <= actually_allocated_size) {
95    // We are not reallocating here.
96    meta->requested_size = new_size;
97    if (new_size > old_size)
98      __msan_poison((char*)old_p + old_size, new_size - old_size);
99    return old_p;
100  }
101  uptr memcpy_size = Min(new_size, old_size);
102  void *new_p = MsanAllocate(stack, new_size, alignment, zeroise);
103  // Printf("realloc: old_size %zd new_size %zd\n", old_size, new_size);
104  if (new_p)
105    __msan_memcpy(new_p, old_p, memcpy_size);
106  MsanDeallocate(old_p);
107  return new_p;
108}
109
110static uptr AllocationSize(const void *p) {
111  if (p == 0)
112    return 0;
113  const void *beg = allocator.GetBlockBegin(p);
114  if (beg != p)
115    return 0;
116  Metadata *b = (Metadata*)allocator.GetMetaData(p);
117  return b->requested_size;
118}
119
120}  // namespace __msan
121
122using namespace __msan;
123
124uptr __msan_get_current_allocated_bytes() {
125  u64 stats[AllocatorStatCount];
126  allocator.GetStats(stats);
127  u64 m = stats[AllocatorStatMalloced];
128  u64 f = stats[AllocatorStatFreed];
129  return m >= f ? m - f : 1;
130}
131
132uptr __msan_get_heap_size() {
133  u64 stats[AllocatorStatCount];
134  allocator.GetStats(stats);
135  u64 m = stats[AllocatorStatMmapped];
136  u64 f = stats[AllocatorStatUnmapped];
137  return m >= f ? m - f : 1;
138}
139
140uptr __msan_get_free_bytes() {
141  return 1;
142}
143
144uptr __msan_get_unmapped_bytes() {
145  return 1;
146}
147
148uptr __msan_get_estimated_allocated_size(uptr size) {
149  return size;
150}
151
152int __msan_get_ownership(const void *p) {
153  return AllocationSize(p) != 0;
154}
155
156uptr __msan_get_allocated_size(const void *p) {
157  return AllocationSize(p);
158}
159