msan_allocator.cc revision effdc7e483708cfa4dc597c21f246c5dbc09daa0 
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),
62               0);  // Higher bit is occupied by stack origins.
63      __msan_set_origin(res, size, stack_id);
64    }
65  }
66  MSAN_MALLOC_HOOK(res, size);
67  return res;
68}
69
70void MsanDeallocate(StackTrace *stack, void *p) {
71  CHECK(p);
72  Init();
73  MSAN_FREE_HOOK(p);
74  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(p));
75  uptr size = meta->requested_size;
76  meta->requested_size = 0;
77  // This memory will not be reused by anyone else, so we are free to keep it
78  // poisoned.
79  if (flags()->poison_in_free) {
80    __msan_poison(p, size);
81    if (__msan_get_track_origins()) {
82      u32 stack_id = StackDepotPut(stack->trace, stack->size);
83      CHECK(stack_id);
84      CHECK_EQ((stack_id >> 31),
85               0);  // Higher bit is occupied by stack origins.
86      __msan_set_origin(p, size, stack_id);
87    }
88  }
89  allocator.Deallocate(&cache, p);
90}
91
92void *MsanReallocate(StackTrace *stack, void *old_p, uptr new_size,
93                     uptr alignment, bool zeroise) {
94  if (!old_p)
95    return MsanAllocate(stack, new_size, alignment, zeroise);
96  if (!new_size) {
97    MsanDeallocate(stack, old_p);
98    return 0;
99  }
100  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(old_p));
101  uptr old_size = meta->requested_size;
102  uptr actually_allocated_size = allocator.GetActuallyAllocatedSize(old_p);
103  if (new_size <= actually_allocated_size) {
104    // We are not reallocating here.
105    meta->requested_size = new_size;
106    if (new_size > old_size)
107      __msan_poison((char*)old_p + old_size, new_size - old_size);
108    return old_p;
109  }
110  uptr memcpy_size = Min(new_size, old_size);
111  void *new_p = MsanAllocate(stack, new_size, alignment, zeroise);
112  // Printf("realloc: old_size %zd new_size %zd\n", old_size, new_size);
113  if (new_p)
114    __msan_memcpy(new_p, old_p, memcpy_size);
115  MsanDeallocate(stack, old_p);
116  return new_p;
117}
118
119static uptr AllocationSize(const void *p) {
120  if (p == 0)
121    return 0;
122  const void *beg = allocator.GetBlockBegin(p);
123  if (beg != p)
124    return 0;
125  Metadata *b = (Metadata*)allocator.GetMetaData(p);
126  return b->requested_size;
127}
128
129}  // namespace __msan
130
131using namespace __msan;
132
133uptr __msan_get_current_allocated_bytes() {
134  u64 stats[AllocatorStatCount];
135  allocator.GetStats(stats);
136  u64 m = stats[AllocatorStatMalloced];
137  u64 f = stats[AllocatorStatFreed];
138  return m >= f ? m - f : 1;
139}
140
141uptr __msan_get_heap_size() {
142  u64 stats[AllocatorStatCount];
143  allocator.GetStats(stats);
144  u64 m = stats[AllocatorStatMmapped];
145  u64 f = stats[AllocatorStatUnmapped];
146  return m >= f ? m - f : 1;
147}
148
149uptr __msan_get_free_bytes() {
150  return 1;
151}
152
153uptr __msan_get_unmapped_bytes() {
154  return 1;
155}
156
157uptr __msan_get_estimated_allocated_size(uptr size) {
158  return size;
159}
160
161int __msan_get_ownership(const void *p) {
162  return AllocationSize(p) != 0;
163}
164
165uptr __msan_get_allocated_size(const void *p) {
166  return AllocationSize(p);
167}
168