src/libcompiler_builtins/compiler-rt/lib/sanitizer_common/sanitizer_allocator_combined.h

   1 //===-- sanitizer_allocator_combined.h --------------------------*- C++ -*-===//
   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 // Part of the Sanitizer Allocator.
  11 //
  12 //===----------------------------------------------------------------------===//
  13 #ifndef SANITIZER_ALLOCATOR_H
  14 #error This file must be included inside sanitizer_allocator.h
  15 #endif
  16
  17 // This class implements a complete memory allocator by using two
  18 // internal allocators:
  19 // PrimaryAllocator is efficient, but may not allocate some sizes (alignments).
  20 //  When allocating 2^x bytes it should return 2^x aligned chunk.
  21 // PrimaryAllocator is used via a local AllocatorCache.
  22 // SecondaryAllocator can allocate anything, but is not efficient.
  23 template <class PrimaryAllocator, class AllocatorCache,
  24           class SecondaryAllocator>  // NOLINT
  25 class CombinedAllocator {
  26  public:
  27   void InitCommon(bool may_return_null, s32 release_to_os_interval_ms) {
  28     primary_.Init(release_to_os_interval_ms);
  29     atomic_store(&may_return_null_, may_return_null, memory_order_relaxed);
  30   }
  31
  32   void InitLinkerInitialized(
  33       bool may_return_null, s32 release_to_os_interval_ms) {
  34     secondary_.InitLinkerInitialized(may_return_null);
  35     stats_.InitLinkerInitialized();
  36     InitCommon(may_return_null, release_to_os_interval_ms);
  37   }
  38
  39   void Init(bool may_return_null, s32 release_to_os_interval_ms) {
  40     secondary_.Init(may_return_null);
  41     stats_.Init();
  42     InitCommon(may_return_null, release_to_os_interval_ms);
  43   }
  44
  45   void *Allocate(AllocatorCache *cache, uptr size, uptr alignment,
  46                  bool cleared = false, bool check_rss_limit = false) {
  47     // Returning 0 on malloc(0) may break a lot of code.
  48     if (size == 0)
  49       size = 1;
  50     if (size + alignment < size) return ReturnNullOrDieOnBadRequest();
  51     if (check_rss_limit && RssLimitIsExceeded()) return ReturnNullOrDieOnOOM();
  52     uptr original_size = size;
  53     // If alignment requirements are to be fulfilled by the frontend allocator
  54     // rather than by the primary or secondary, passing an alignment lower than
  55     // or equal to 8 will prevent any further rounding up, as well as the later
  56     // alignment check.
  57     if (alignment > 8)
  58       size = RoundUpTo(size, alignment);
  59     void *res;
  60     bool from_primary = primary_.CanAllocate(size, alignment);
  61     // The primary allocator should return a 2^x aligned allocation when
  62     // requested 2^x bytes, hence using the rounded up 'size' when being
  63     // serviced by the primary (this is no longer true when the primary is
  64     // using a non-fixed base address). The secondary takes care of the
  65     // alignment without such requirement, and allocating 'size' would use
  66     // extraneous memory, so we employ 'original_size'.
  67     if (from_primary)
  68       res = cache->Allocate(&primary_, primary_.ClassID(size));
  69     else
  70       res = secondary_.Allocate(&stats_, original_size, alignment);
  71     if (alignment > 8)
  72       CHECK_EQ(reinterpret_cast<uptr>(res) & (alignment - 1), 0);
  73     // When serviced by the secondary, the chunk comes from a mmap allocation
  74     // and will be zero'd out anyway. We only need to clear our the chunk if
  75     // it was serviced by the primary, hence using the rounded up 'size'.
  76     if (cleared && res && from_primary)
  77       internal_bzero_aligned16(res, RoundUpTo(size, 16));
  78     return res;
  79   }
  80
  81   bool MayReturnNull() const {
  82     return atomic_load(&may_return_null_, memory_order_acquire);
  83   }
  84
  85   void *ReturnNullOrDieOnBadRequest() {
  86     if (MayReturnNull())
  87       return nullptr;
  88     ReportAllocatorCannotReturnNull(false);
  89   }
  90
  91   void *ReturnNullOrDieOnOOM() {
  92     if (MayReturnNull()) return nullptr;
  93     ReportAllocatorCannotReturnNull(true);
  94   }
  95
  96   void SetMayReturnNull(bool may_return_null) {
  97     secondary_.SetMayReturnNull(may_return_null);
  98     atomic_store(&may_return_null_, may_return_null, memory_order_release);
  99   }
 100
 101   s32 ReleaseToOSIntervalMs() const {
 102     return primary_.ReleaseToOSIntervalMs();
 103   }
 104
 105   void SetReleaseToOSIntervalMs(s32 release_to_os_interval_ms) {
 106     primary_.SetReleaseToOSIntervalMs(release_to_os_interval_ms);
 107   }
 108
 109   bool RssLimitIsExceeded() {
 110     return atomic_load(&rss_limit_is_exceeded_, memory_order_acquire);
 111   }
 112
 113   void SetRssLimitIsExceeded(bool rss_limit_is_exceeded) {
 114     atomic_store(&rss_limit_is_exceeded_, rss_limit_is_exceeded,
 115                  memory_order_release);
 116   }
 117
 118   void Deallocate(AllocatorCache *cache, void *p) {
 119     if (!p) return;
 120     if (primary_.PointerIsMine(p))
 121       cache->Deallocate(&primary_, primary_.GetSizeClass(p), p);
 122     else
 123       secondary_.Deallocate(&stats_, p);
 124   }
 125
 126   void *Reallocate(AllocatorCache *cache, void *p, uptr new_size,
 127                    uptr alignment) {
 128     if (!p)
 129       return Allocate(cache, new_size, alignment);
 130     if (!new_size) {
 131       Deallocate(cache, p);
 132       return nullptr;
 133     }
 134     CHECK(PointerIsMine(p));
 135     uptr old_size = GetActuallyAllocatedSize(p);
 136     uptr memcpy_size = Min(new_size, old_size);
 137     void *new_p = Allocate(cache, new_size, alignment);
 138     if (new_p)
 139       internal_memcpy(new_p, p, memcpy_size);
 140     Deallocate(cache, p);
 141     return new_p;
 142   }
 143
 144   bool PointerIsMine(void *p) {
 145     if (primary_.PointerIsMine(p))
 146       return true;
 147     return secondary_.PointerIsMine(p);
 148   }
 149
 150   bool FromPrimary(void *p) {
 151     return primary_.PointerIsMine(p);
 152   }
 153
 154   void *GetMetaData(const void *p) {
 155     if (primary_.PointerIsMine(p))
 156       return primary_.GetMetaData(p);
 157     return secondary_.GetMetaData(p);
 158   }
 159
 160   void *GetBlockBegin(const void *p) {
 161     if (primary_.PointerIsMine(p))
 162       return primary_.GetBlockBegin(p);
 163     return secondary_.GetBlockBegin(p);
 164   }
 165
 166   // This function does the same as GetBlockBegin, but is much faster.
 167   // Must be called with the allocator locked.
 168   void *GetBlockBeginFastLocked(void *p) {
 169     if (primary_.PointerIsMine(p))
 170       return primary_.GetBlockBegin(p);
 171     return secondary_.GetBlockBeginFastLocked(p);
 172   }
 173
 174   uptr GetActuallyAllocatedSize(void *p) {
 175     if (primary_.PointerIsMine(p))
 176       return primary_.GetActuallyAllocatedSize(p);
 177     return secondary_.GetActuallyAllocatedSize(p);
 178   }
 179
 180   uptr TotalMemoryUsed() {
 181     return primary_.TotalMemoryUsed() + secondary_.TotalMemoryUsed();
 182   }
 183
 184   void TestOnlyUnmap() { primary_.TestOnlyUnmap(); }
 185
 186   void InitCache(AllocatorCache *cache) {
 187     cache->Init(&stats_);
 188   }
 189
 190   void DestroyCache(AllocatorCache *cache) {
 191     cache->Destroy(&primary_, &stats_);
 192   }
 193
 194   void SwallowCache(AllocatorCache *cache) {
 195     cache->Drain(&primary_);
 196   }
 197
 198   void GetStats(AllocatorStatCounters s) const {
 199     stats_.Get(s);
 200   }
 201
 202   void PrintStats() {
 203     primary_.PrintStats();
 204     secondary_.PrintStats();
 205   }
 206
 207   // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
 208   // introspection API.
 209   void ForceLock() {
 210     primary_.ForceLock();
 211     secondary_.ForceLock();
 212   }
 213
 214   void ForceUnlock() {
 215     secondary_.ForceUnlock();
 216     primary_.ForceUnlock();
 217   }
 218
 219   // Iterate over all existing chunks.
 220   // The allocator must be locked when calling this function.
 221   void ForEachChunk(ForEachChunkCallback callback, void *arg) {
 222     primary_.ForEachChunk(callback, arg);
 223     secondary_.ForEachChunk(callback, arg);
 224   }
 225
 226  private:
 227   PrimaryAllocator primary_;
 228   SecondaryAllocator secondary_;
 229   AllocatorGlobalStats stats_;
 230   atomic_uint8_t may_return_null_;
 231   atomic_uint8_t rss_limit_is_exceeded_;
 232 };
 233