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
19 namespace __msan {
20
21 struct Metadata {
22 uptr requested_size;
23 };
24
25 static const uptr kAllocatorSpace = 0x600000000000ULL;
26 static const uptr kAllocatorSize = 0x80000000000; // 8T.
27 static const uptr kMetadataSize = sizeof(Metadata);
28
29 typedef SizeClassAllocator64<kAllocatorSpace, kAllocatorSize, kMetadataSize,
30 DefaultSizeClassMap> PrimaryAllocator;
31 typedef SizeClassAllocatorLocalCache<PrimaryAllocator> AllocatorCache;
32 typedef LargeMmapAllocator<> SecondaryAllocator;
33 typedef CombinedAllocator<PrimaryAllocator, AllocatorCache,
34 SecondaryAllocator> Allocator;
35
36 static THREADLOCAL AllocatorCache cache;
37 static Allocator allocator;
38
39 static int inited = 0;
40
Init()41 static 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
MsanAllocate(StackTrace * stack,uptr size,uptr alignment,bool zeroise)48 static 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
MsanDeallocate(void * p)68 void 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
MsanReallocate(StackTrace * stack,void * old_p,uptr new_size,uptr alignment,bool zeroise)83 void *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
AllocationSize(const void * p)110 static 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
122 using namespace __msan;
123
__msan_get_current_allocated_bytes()124 uptr __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
__msan_get_heap_size()132 uptr __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
__msan_get_free_bytes()140 uptr __msan_get_free_bytes() {
141 return 1;
142 }
143
__msan_get_unmapped_bytes()144 uptr __msan_get_unmapped_bytes() {
145 return 1;
146 }
147
__msan_get_estimated_allocated_size(uptr size)148 uptr __msan_get_estimated_allocated_size(uptr size) {
149 return size;
150 }
151
__msan_get_ownership(const void * p)152 bool __msan_get_ownership(const void *p) {
153 return AllocationSize(p) != 0;
154 }
155
__msan_get_allocated_size(const void * p)156 uptr __msan_get_allocated_size(const void *p) {
157 return AllocationSize(p);
158 }
159