1//===-- sanitizer_allocator.cpp -------------------------------------------===//
2//
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
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is shared between AddressSanitizer and ThreadSanitizer
10// run-time libraries.
11// This allocator is used inside run-times.
12//===----------------------------------------------------------------------===//
13
14#include "sanitizer_allocator.h"
15
16#include "sanitizer_allocator_checks.h"
17#include "sanitizer_allocator_internal.h"
18#include "sanitizer_atomic.h"
19#include "sanitizer_common.h"
20#include "sanitizer_platform.h"
21
22namespace __sanitizer {
23
24// Default allocator names.
25const char *PrimaryAllocatorName = "SizeClassAllocator";
26const char *SecondaryAllocatorName = "LargeMmapAllocator";
27
28alignas(64) static char internal_alloc_placeholder[sizeof(InternalAllocator)];
29static atomic_uint8_t internal_allocator_initialized;
30static StaticSpinMutex internal_alloc_init_mu;
31
32static InternalAllocatorCache internal_allocator_cache;
33static StaticSpinMutex internal_allocator_cache_mu;
34
35InternalAllocator *internal_allocator() {
36 InternalAllocator *internal_allocator_instance =
37 reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
38 if (atomic_load(a: &internal_allocator_initialized, mo: memory_order_acquire) == 0) {
39 SpinMutexLock l(&internal_alloc_init_mu);
40 if (atomic_load(a: &internal_allocator_initialized, mo: memory_order_relaxed) ==
41 0) {
42 internal_allocator_instance->Init(release_to_os_interval_ms: kReleaseToOSIntervalNever);
43 atomic_store(a: &internal_allocator_initialized, v: 1, mo: memory_order_release);
44 }
45 }
46 return internal_allocator_instance;
47}
48
49static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
50 uptr alignment) {
51 if (alignment == 0) alignment = 8;
52 if (cache == 0) {
53 SpinMutexLock l(&internal_allocator_cache_mu);
54 return internal_allocator()->Allocate(cache: &internal_allocator_cache, size,
55 alignment);
56 }
57 return internal_allocator()->Allocate(cache, size, alignment);
58}
59
60static void *RawInternalRealloc(void *ptr, uptr size,
61 InternalAllocatorCache *cache) {
62 constexpr usize alignment = Max<usize>(a: 8, b: sizeof(void *));
63 if (cache == 0) {
64 SpinMutexLock l(&internal_allocator_cache_mu);
65 return internal_allocator()->Reallocate(cache: &internal_allocator_cache, p: ptr,
66 new_size: size, alignment);
67 }
68 return internal_allocator()->Reallocate(cache, p: ptr, new_size: size, alignment);
69}
70
71static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
72 if (!cache) {
73 SpinMutexLock l(&internal_allocator_cache_mu);
74 return internal_allocator()->Deallocate(cache: &internal_allocator_cache, p: ptr);
75 }
76 internal_allocator()->Deallocate(cache, p: ptr);
77}
78
79static void NORETURN ReportInternalAllocatorOutOfMemory(uptr requested_size) {
80 SetAllocatorOutOfMemory();
81 Report(format: "FATAL: %s: internal allocator is out of memory trying to allocate "
82 "0x%zx bytes\n", SanitizerToolName, requested_size);
83 Die();
84}
85
86void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
87 void *p = RawInternalAlloc(size, cache, alignment);
88 if (UNLIKELY(!p))
89 ReportInternalAllocatorOutOfMemory(requested_size: size);
90 return p;
91}
92
93void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
94 void *p = RawInternalRealloc(ptr: addr, size, cache);
95 if (UNLIKELY(!p))
96 ReportInternalAllocatorOutOfMemory(requested_size: size);
97 return p;
98}
99
100void *InternalReallocArray(void *addr, uptr count, uptr size,
101 InternalAllocatorCache *cache) {
102 if (UNLIKELY(CheckForCallocOverflow(count, size))) {
103 Report(
104 format: "FATAL: %s: reallocarray parameters overflow: count * size (%zd * %zd) "
105 "cannot be represented in type size_t\n",
106 SanitizerToolName, count, size);
107 Die();
108 }
109 return InternalRealloc(addr, size: count * size, cache);
110}
111
112void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
113 if (UNLIKELY(CheckForCallocOverflow(count, size))) {
114 Report(format: "FATAL: %s: calloc parameters overflow: count * size (%zd * %zd) "
115 "cannot be represented in type size_t\n", SanitizerToolName, count,
116 size);
117 Die();
118 }
119 void *p = InternalAlloc(size: count * size, cache);
120 if (LIKELY(p))
121 internal_memset(s: p, c: 0, n: count * size);
122 return p;
123}
124
125void InternalFree(void *addr, InternalAllocatorCache *cache) {
126 RawInternalFree(ptr: addr, cache);
127}
128
129void InternalAllocatorLock() SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
130 internal_allocator_cache_mu.Lock();
131 internal_allocator()->ForceLock();
132}
133
134void InternalAllocatorUnlock() SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
135 internal_allocator()->ForceUnlock();
136 internal_allocator_cache_mu.Unlock();
137}
138
139// LowLevelAllocator
140constexpr usize kLowLevelAllocatorDefaultAlignment =
141 Max<usize>(a: 8, b: sizeof(void *));
142constexpr uptr kMinNumPagesRounded = 16;
143constexpr uptr kMinRoundedSize = 65536;
144static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
145static LowLevelAllocateCallback low_level_alloc_callback;
146
147static LowLevelAllocator Alloc;
148LowLevelAllocator &GetGlobalLowLevelAllocator() { return Alloc; }
149
150void *LowLevelAllocator::Allocate(uptr size) {
151 // Align allocation size.
152 size = RoundUpTo(size, boundary: low_level_alloc_min_alignment);
153 if (allocated_end_ - allocated_current_ < (sptr)size) {
154 uptr size_to_allocate = RoundUpTo(
155 size, boundary: Min(a: GetPageSizeCached() * kMinNumPagesRounded, b: kMinRoundedSize));
156 allocated_current_ = (char *)MmapOrDie(size: size_to_allocate, mem_type: __func__);
157 allocated_end_ = allocated_current_ + size_to_allocate;
158 if (low_level_alloc_callback) {
159 low_level_alloc_callback((uptr)allocated_current_, size_to_allocate);
160 }
161 }
162 CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
163 void *res = allocated_current_;
164 allocated_current_ += size;
165 return res;
166}
167
168void SetLowLevelAllocateMinAlignment(uptr alignment) {
169 CHECK(IsPowerOfTwo(alignment));
170 low_level_alloc_min_alignment = Max(a: alignment, b: low_level_alloc_min_alignment);
171}
172
173void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
174 low_level_alloc_callback = callback;
175}
176
177// Allocator's OOM and other errors handling support.
178
179static atomic_uint8_t allocator_out_of_memory = {.val_dont_use: 0};
180static atomic_uint8_t allocator_may_return_null = {.val_dont_use: 0};
181
182bool IsAllocatorOutOfMemory() {
183 return atomic_load_relaxed(a: &allocator_out_of_memory);
184}
185
186void SetAllocatorOutOfMemory() {
187 atomic_store_relaxed(a: &allocator_out_of_memory, v: 1);
188}
189
190bool AllocatorMayReturnNull() {
191 return atomic_load(a: &allocator_may_return_null, mo: memory_order_relaxed);
192}
193
194void SetAllocatorMayReturnNull(bool may_return_null) {
195 atomic_store(a: &allocator_may_return_null, v: may_return_null,
196 mo: memory_order_relaxed);
197}
198
199void PrintHintAllocatorCannotReturnNull() {
200 Report(format: "HINT: if you don't care about these errors you may set "
201 "allocator_may_return_null=1\n");
202}
203
204static atomic_uint8_t rss_limit_exceeded;
205
206bool IsRssLimitExceeded() {
207 return atomic_load(a: &rss_limit_exceeded, mo: memory_order_relaxed);
208}
209
210void SetRssLimitExceeded(bool limit_exceeded) {
211 atomic_store(a: &rss_limit_exceeded, v: limit_exceeded, mo: memory_order_relaxed);
212}
213
214} // namespace __sanitizer
215