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  return res;
65}
66
67void MsanDeallocate(void *p) {
68  CHECK(p);
69  Init();
70  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(p));
71  uptr size = meta->requested_size;
72  // This memory will not be reused by anyone else, so we are free to keep it
73  // poisoned.
74  __msan_poison(p, size);
75  if (__msan_get_track_origins())
76    __msan_set_origin(p, size, -1);
77  allocator.Deallocate(&cache, p);
78}
79
80void *MsanReallocate(StackTrace *stack, void *old_p, uptr new_size,
81                     uptr alignment, bool zeroise) {
82  if (!old_p)
83    return MsanAllocate(stack, new_size, alignment, zeroise);
84  if (!new_size) {
85    MsanDeallocate(old_p);
86    return 0;
87  }
88  Metadata *meta = reinterpret_cast<Metadata*>(allocator.GetMetaData(old_p));
89  uptr old_size = meta->requested_size;
90  uptr actually_allocated_size = allocator.GetActuallyAllocatedSize(old_p);
91  if (new_size <= actually_allocated_size) {
92    // We are not reallocating here.
93    meta->requested_size = new_size;
94    if (new_size > old_size)
95      __msan_poison((char*)old_p + old_size, new_size - old_size);
96    return old_p;
97  }
98  uptr memcpy_size = Min(new_size, old_size);
99  void *new_p = MsanAllocate(stack, new_size, alignment, zeroise);
100  // Printf("realloc: old_size %zd new_size %zd\n", old_size, new_size);
101  if (new_p)
102    __msan_memcpy(new_p, old_p, memcpy_size);
103  MsanDeallocate(old_p);
104  return new_p;
105}
106
107}  // namespace __msan
108