src/compiler-rt/lib/sanitizer_common/sanitizer_allocator.cc

   1 //===-- sanitizer_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 shared between AddressSanitizer and ThreadSanitizer
  11 // run-time libraries.
  12 // This allocator is used inside run-times.
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "sanitizer_allocator.h"
  16 #include "sanitizer_allocator_internal.h"
  17 #include "sanitizer_common.h"
  18
  19 namespace __sanitizer {
  20
  21 // ThreadSanitizer for Go uses libc malloc/free.
  22 #if defined(SANITIZER_GO) || defined(SANITIZER_USE_MALLOC)
  23 # if SANITIZER_LINUX && !SANITIZER_ANDROID
  24 extern "C" void *__libc_malloc(uptr size);
  25 extern "C" void *__libc_memalign(uptr alignment, uptr size);
  26 extern "C" void *__libc_realloc(void *ptr, uptr size);
  27 extern "C" void __libc_free(void *ptr);
  28 # else
  29 #  include <stdlib.h>
  30 #  define __libc_malloc malloc
  31 static void *__libc_memalign(uptr alignment, uptr size) {
  32   void *p;
  33   uptr error = posix_memalign(&p, alignment, size);
  34   if (error) return nullptr;
  35   return p;
  36 }
  37 #  define __libc_realloc realloc
  38 #  define __libc_free free
  39 # endif
  40
  41 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
  42                               uptr alignment) {
  43   (void)cache;
  44   if (alignment == 0)
  45     return __libc_malloc(size);
  46   else
  47     return __libc_memalign(alignment, size);
  48 }
  49
  50 static void *RawInternalRealloc(void *ptr, uptr size,
  51                                 InternalAllocatorCache *cache) {
  52   (void)cache;
  53   return __libc_realloc(ptr, size);
  54 }
  55
  56 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  57   (void)cache;
  58   __libc_free(ptr);
  59 }
  60
  61 InternalAllocator *internal_allocator() {
  62   return 0;
  63 }
  64
  65 #else  // defined(SANITIZER_GO) || defined(SANITIZER_USE_MALLOC)
  66
  67 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
  68 static atomic_uint8_t internal_allocator_initialized;
  69 static StaticSpinMutex internal_alloc_init_mu;
  70
  71 static InternalAllocatorCache internal_allocator_cache;
  72 static StaticSpinMutex internal_allocator_cache_mu;
  73
  74 InternalAllocator *internal_allocator() {
  75   InternalAllocator *internal_allocator_instance =
  76       reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
  77   if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
  78     SpinMutexLock l(&internal_alloc_init_mu);
  79     if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
  80         0) {
  81       internal_allocator_instance->Init(/* may_return_null*/ false);
  82       atomic_store(&internal_allocator_initialized, 1, memory_order_release);
  83     }
  84   }
  85   return internal_allocator_instance;
  86 }
  87
  88 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
  89                               uptr alignment) {
  90   if (alignment == 0) alignment = 8;
  91   if (cache == 0) {
  92     SpinMutexLock l(&internal_allocator_cache_mu);
  93     return internal_allocator()->Allocate(&internal_allocator_cache, size,
  94                                           alignment, false);
  95   }
  96   return internal_allocator()->Allocate(cache, size, alignment, false);
  97 }
  98
  99 static void *RawInternalRealloc(void *ptr, uptr size,
 100                                 InternalAllocatorCache *cache) {
 101   uptr alignment = 8;
 102   if (cache == 0) {
 103     SpinMutexLock l(&internal_allocator_cache_mu);
 104     return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
 105                                             size, alignment);
 106   }
 107   return internal_allocator()->Reallocate(cache, ptr, size, alignment);
 108 }
 109
 110 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
 111   if (!cache) {
 112     SpinMutexLock l(&internal_allocator_cache_mu);
 113     return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
 114   }
 115   internal_allocator()->Deallocate(cache, ptr);
 116 }
 117
 118 #endif  // defined(SANITIZER_GO) || defined(SANITIZER_USE_MALLOC)
 119
 120 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
 121
 122 void *InternalAlloc(uptr size, InternalAllocatorCache *cache, uptr alignment) {
 123   if (size + sizeof(u64) < size)
 124     return nullptr;
 125   void *p = RawInternalAlloc(size + sizeof(u64), cache, alignment);
 126   if (!p)
 127     return nullptr;
 128   ((u64*)p)[0] = kBlockMagic;
 129   return (char*)p + sizeof(u64);
 130 }
 131
 132 void *InternalRealloc(void *addr, uptr size, InternalAllocatorCache *cache) {
 133   if (!addr)
 134     return InternalAlloc(size, cache);
 135   if (size + sizeof(u64) < size)
 136     return nullptr;
 137   addr = (char*)addr - sizeof(u64);
 138   size = size + sizeof(u64);
 139   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 140   void *p = RawInternalRealloc(addr, size, cache);
 141   if (!p)
 142     return nullptr;
 143   return (char*)p + sizeof(u64);
 144 }
 145
 146 void *InternalCalloc(uptr count, uptr size, InternalAllocatorCache *cache) {
 147   if (CallocShouldReturnNullDueToOverflow(count, size))
 148     return internal_allocator()->ReturnNullOrDie();
 149   void *p = InternalAlloc(count * size, cache);
 150   if (p) internal_memset(p, 0, count * size);
 151   return p;
 152 }
 153
 154 void InternalFree(void *addr, InternalAllocatorCache *cache) {
 155   if (!addr)
 156     return;
 157   addr = (char*)addr - sizeof(u64);
 158   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 159   ((u64*)addr)[0] = 0;
 160   RawInternalFree(addr, cache);
 161 }
 162
 163 // LowLevelAllocator
 164 static LowLevelAllocateCallback low_level_alloc_callback;
 165
 166 void *LowLevelAllocator::Allocate(uptr size) {
 167   // Align allocation size.
 168   size = RoundUpTo(size, 8);
 169   if (allocated_end_ - allocated_current_ < (sptr)size) {
 170     uptr size_to_allocate = Max(size, GetPageSizeCached());
 171     allocated_current_ =
 172         (char*)MmapOrDie(size_to_allocate, __func__);
 173     allocated_end_ = allocated_current_ + size_to_allocate;
 174     if (low_level_alloc_callback) {
 175       low_level_alloc_callback((uptr)allocated_current_,
 176                                size_to_allocate);
 177     }
 178   }
 179   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
 180   void *res = allocated_current_;
 181   allocated_current_ += size;
 182   return res;
 183 }
 184
 185 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
 186   low_level_alloc_callback = callback;
 187 }
 188
 189 bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
 190   if (!size) return false;
 191   uptr max = (uptr)-1L;
 192   return (max / size) < n;
 193 }
 194
 195 void NORETURN ReportAllocatorCannotReturnNull() {
 196   Report("%s's allocator is terminating the process instead of returning 0\n",
 197          SanitizerToolName);
 198   Report("If you don't like this behavior set allocator_may_return_null=1\n");
 199   CHECK(0);
 200   Die();
 201 }
 202
 203 } // namespace __sanitizer