1 //===-- sanitizer_allocator.cc --------------------------------------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file is shared between AddressSanitizer and ThreadSanitizer
10 // run-time libraries.
11 // This allocator is used inside run-times.
12 //===----------------------------------------------------------------------===//
14 #include "sanitizer_allocator.h"
16 #include "sanitizer_allocator_checks.h"
17 #include "sanitizer_allocator_internal.h"
18 #include "sanitizer_atomic.h"
19 #include "sanitizer_common.h"
21 namespace __sanitizer {
23 // Default allocator names.
24 const char *PrimaryAllocatorName = "SizeClassAllocator";
25 const char *SecondaryAllocatorName = "LargeMmapAllocator";
27 // ThreadSanitizer for Go uses libc malloc/free.
28 #if SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
29 # if SANITIZER_LINUX && !SANITIZER_ANDROID
30 extern "C" void *__libc_malloc(uptr size);
32 extern "C" void *__libc_memalign(uptr alignment, uptr size);
34 extern "C" void *__libc_realloc(void *ptr, uptr size);
35 extern "C" void __libc_free(void *ptr);
38 # define __libc_malloc malloc
40 static void *__libc_memalign(uptr alignment, uptr size) {
42 uptr error = posix_memalign(&p, alignment, size);
43 if (error) return nullptr;
47 # define __libc_realloc realloc
48 # define __libc_free free
51 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
56 return __libc_malloc(size);
58 return __libc_memalign(alignment, size);
60 // Windows does not provide __libc_memalign/posix_memalign. It provides
61 // __aligned_malloc, but the allocated blocks can't be passed to free,
62 // they need to be passed to __aligned_free. InternalAlloc interface does
63 // not account for such requirement. Alignemnt does not seem to be used
64 // anywhere in runtime, so just call __libc_malloc for now.
65 DCHECK_EQ(alignment, 0);
66 return __libc_malloc(size);
70 static void *RawInternalRealloc(void *ptr, uptr size,
71 InternalAllocatorCache *cache) {
73 return __libc_realloc(ptr, size);
76 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
81 InternalAllocator *internal_allocator() {
85 #else // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
87 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
88 static atomic_uint8_t internal_allocator_initialized;
89 static StaticSpinMutex internal_alloc_init_mu;
91 static InternalAllocatorCache internal_allocator_cache;
92 static StaticSpinMutex internal_allocator_cache_mu;
94 InternalAllocator *internal_allocator() {
95 InternalAllocator *internal_allocator_instance =
96 reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
97 if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
98 SpinMutexLock l(&internal_alloc_init_mu);
99 if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
101 internal_allocator_instance->Init(kReleaseToOSIntervalNever);
102 atomic_store(&internal_allocator_initialized, 1, memory_order_release);
105 return internal_allocator_instance;
108 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
110 if (alignment == 0) alignment = 8;
112 SpinMutexLock l(&internal_allocator_cache_mu);
113 return internal_allocator()->Allocate(&internal_allocator_cache, size,
116 return internal_allocator()->Allocate(cache, size, alignment);
119 static void *RawInternalRealloc(void *ptr, uptr size,
120 InternalAllocatorCache *cache) {
123 SpinMutexLock l(&internal_allocator_cache_mu);
124 return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
127 return internal_allocator()->Reallocate(cache, ptr, size, alignment);
130 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
132 SpinMutexLock l(&internal_allocator_cache_mu);
133 return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
135 internal_allocator()->Deallocate(cache, ptr);
138 #endif // SANITIZER_GO || defined(SANITIZER_USE_MALLOC)
140 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
142 static void NORETURN ReportInternalAllocatorOutOfMemory(uptr requested_size) {
143 SetAllocatorOutOfMemory();
144 Report("FATAL: %s: internal allocator is out of memory trying to allocate "
145 "0x%zx bytes\n", SanitizerToolName, requested_size);
149 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
150 if (size + sizeof(u64) < size)
152 void *p = RawInternalAlloc(size + sizeof(u64), cache, alignment);
154 ReportInternalAllocatorOutOfMemory(size + sizeof(u64));
155 ((u64*)p)[0] = kBlockMagic;
156 return (char*)p + sizeof(u64);
159 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
161 return InternalAlloc(size, cache);
162 if (size + sizeof(u64) < size)
164 addr = (char*)addr - sizeof(u64);
165 size = size + sizeof(u64);
166 CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
167 void *p = RawInternalRealloc(addr, size, cache);
169 ReportInternalAllocatorOutOfMemory(size);
170 return (char*)p + sizeof(u64);
173 void *InternalReallocArray(void *addr, uptr count, uptr size,
174 InternalAllocatorCache *cache) {
175 if (UNLIKELY(CheckForCallocOverflow(count, size))) {
177 "FATAL: %s: reallocarray parameters overflow: count * size (%zd * %zd) "
178 "cannot be represented in type size_t\n",
179 SanitizerToolName, count, size);
182 return InternalRealloc(addr, count * size, cache);
185 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
186 if (UNLIKELY(CheckForCallocOverflow(count, size))) {
187 Report("FATAL: %s: calloc parameters overflow: count * size (%zd * %zd) "
188 "cannot be represented in type size_t\n", SanitizerToolName, count,
192 void *p = InternalAlloc(count * size, cache);
194 internal_memset(p, 0, count * size);
198 void InternalFree(void *addr, InternalAllocatorCache *cache) {
201 addr = (char*)addr - sizeof(u64);
202 CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
204 RawInternalFree(addr, cache);
208 constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
209 static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
210 static LowLevelAllocateCallback low_level_alloc_callback;
212 void *LowLevelAllocator::Allocate(uptr size) {
213 // Align allocation size.
214 size = RoundUpTo(size, low_level_alloc_min_alignment);
215 if (allocated_end_ - allocated_current_ < (sptr)size) {
216 uptr size_to_allocate = Max(size, GetPageSizeCached());
218 (char*)MmapOrDie(size_to_allocate, __func__);
219 allocated_end_ = allocated_current_ + size_to_allocate;
220 if (low_level_alloc_callback) {
221 low_level_alloc_callback((uptr)allocated_current_,
225 CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
226 void *res = allocated_current_;
227 allocated_current_ += size;
231 void SetLowLevelAllocateMinAlignment(uptr alignment) {
232 CHECK(IsPowerOfTwo(alignment));
233 low_level_alloc_min_alignment = Max(alignment, low_level_alloc_min_alignment);
236 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
237 low_level_alloc_callback = callback;
240 // Allocator's OOM and other errors handling support.
242 static atomic_uint8_t allocator_out_of_memory = {0};
243 static atomic_uint8_t allocator_may_return_null = {0};
245 bool IsAllocatorOutOfMemory() {
246 return atomic_load_relaxed(&allocator_out_of_memory);
249 void SetAllocatorOutOfMemory() {
250 atomic_store_relaxed(&allocator_out_of_memory, 1);
253 bool AllocatorMayReturnNull() {
254 return atomic_load(&allocator_may_return_null, memory_order_relaxed);
257 void SetAllocatorMayReturnNull(bool may_return_null) {
258 atomic_store(&allocator_may_return_null, may_return_null,
259 memory_order_relaxed);
262 void PrintHintAllocatorCannotReturnNull() {
263 Report("HINT: if you don't care about these errors you may set "
264 "allocator_may_return_null=1\n");
267 } // namespace __sanitizer