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 #include "sanitizer_allocator.h"
  15 #include "sanitizer_allocator_internal.h"
  16 #include "sanitizer_common.h"
  17 #include "sanitizer_flags.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_free(void *ptr);
  26 #  define LIBC_MALLOC __libc_malloc
  27 #  define LIBC_FREE __libc_free
  28 # else
  29 #  include <stdlib.h>
  30 #  define LIBC_MALLOC malloc
  31 #  define LIBC_FREE free
  32 # endif
  33
  34 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache) {
  35   (void)cache;
  36   return LIBC_MALLOC(size);
  37 }
  38
  39 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  40   (void)cache;
  41   LIBC_FREE(ptr);
  42 }
  43
  44 InternalAllocator *internal_allocator() {
  45   return 0;
  46 }
  47
  48 #else  // SANITIZER_GO
  49
  50 static ALIGNED(64) char internal_alloc_placeholder[sizeof(InternalAllocator)];
  51 static atomic_uint8_t internal_allocator_initialized;
  52 static StaticSpinMutex internal_alloc_init_mu;
  53
  54 static InternalAllocatorCache internal_allocator_cache;
  55 static StaticSpinMutex internal_allocator_cache_mu;
  56
  57 InternalAllocator *internal_allocator() {
  58   InternalAllocator *internal_allocator_instance =
  59       reinterpret_cast<InternalAllocator *>(&internal_alloc_placeholder);
  60   if (atomic_load(&internal_allocator_initialized, memory_order_acquire) == 0) {
  61     SpinMutexLock l(&internal_alloc_init_mu);
  62     if (atomic_load(&internal_allocator_initialized, memory_order_relaxed) ==
  63         0) {
  64       internal_allocator_instance->Init();
  65       atomic_store(&internal_allocator_initialized, 1, memory_order_release);
  66     }
  67   }
  68   return internal_allocator_instance;
  69 }
  70
  71 static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache) {
  72   if (cache == 0) {
  73     SpinMutexLock l(&internal_allocator_cache_mu);
  74     return internal_allocator()->Allocate(&internal_allocator_cache, size, 8,
  75                                           false);
  76   }
  77   return internal_allocator()->Allocate(cache, size, 8, false);
  78 }
  79
  80 static void RawInternalFree(void *ptr, InternalAllocatorCache *cache) {
  81   if (cache == 0) {
  82     SpinMutexLock l(&internal_allocator_cache_mu);
  83     return internal_allocator()->Deallocate(&internal_allocator_cache, ptr);
  84   }
  85   internal_allocator()->Deallocate(cache, ptr);
  86 }
  87
  88 #endif  // SANITIZER_GO
  89
  90 const u64 kBlockMagic = 0x6A6CB03ABCEBC041ull;
  91
  92 void *InternalAlloc(uptr size, InternalAllocatorCache *cache) {
  93   if (size + sizeof(u64) < size)
  94     return 0;
  95   void *p = RawInternalAlloc(size + sizeof(u64), cache);
  96   if (p == 0)
  97     return 0;
  98   ((u64*)p)[0] = kBlockMagic;
  99   return (char*)p + sizeof(u64);
 100 }
 101
 102 void InternalFree(void *addr, InternalAllocatorCache *cache) {
 103   if (addr == 0)
 104     return;
 105   addr = (char*)addr - sizeof(u64);
 106   CHECK_EQ(kBlockMagic, ((u64*)addr)[0]);
 107   ((u64*)addr)[0] = 0;
 108   RawInternalFree(addr, cache);
 109 }
 110
 111 // LowLevelAllocator
 112 static LowLevelAllocateCallback low_level_alloc_callback;
 113
 114 void *LowLevelAllocator::Allocate(uptr size) {
 115   // Align allocation size.
 116   size = RoundUpTo(size, 8);
 117   if (allocated_end_ - allocated_current_ < (sptr)size) {
 118     uptr size_to_allocate = Max(size, GetPageSizeCached());
 119     allocated_current_ =
 120         (char*)MmapOrDie(size_to_allocate, __func__);
 121     allocated_end_ = allocated_current_ + size_to_allocate;
 122     if (low_level_alloc_callback) {
 123       low_level_alloc_callback((uptr)allocated_current_,
 124                                size_to_allocate);
 125     }
 126   }
 127   CHECK(allocated_end_ - allocated_current_ >= (sptr)size);
 128   void *res = allocated_current_;
 129   allocated_current_ += size;
 130   return res;
 131 }
 132
 133 void SetLowLevelAllocateCallback(LowLevelAllocateCallback callback) {
 134   low_level_alloc_callback = callback;
 135 }
 136
 137 bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n) {
 138   if (!size) return false;
 139   uptr max = (uptr)-1L;
 140   return (max / size) < n;
 141 }
 142
 143 void *AllocatorReturnNull() {
 144   if (common_flags()->allocator_may_return_null)
 145     return 0;
 146   Report("%s's allocator is terminating the process instead of returning 0\n",
 147          SanitizerToolName);
 148   Report("If you don't like this behavior set allocator_may_return_null=1\n");
 149   CHECK(0);
 150   return 0;
 151 }
 152
 153 }  // namespace __sanitizer