compiler-rt/lib/sanitizer_common/sanitizer_allocator_secondary.h

   1 //===-- sanitizer_allocator_secondary.h -------------------------*- C++ -*-===//
   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 // Part of the Sanitizer Allocator.
  10 //
  11 //===----------------------------------------------------------------------===//
  12 #ifndef SANITIZER_ALLOCATOR_H
  13 #error This file must be included inside sanitizer_allocator.h
  14 #endif
  15
  16 // Fixed array to store LargeMmapAllocator chunks list, limited to 32K total
  17 // allocated chunks. To be used in memory constrained or not memory hungry cases
  18 // (currently, 32 bits and internal allocator).
  19 class LargeMmapAllocatorPtrArrayStatic {
  20  public:
  21   inline void *Init() { return &p_[0]; }
  22   inline void EnsureSpace(uptr n) { CHECK_LT(n, kMaxNumChunks); }
  23  private:
  24   static const int kMaxNumChunks = 1 << 15;
  25   uptr p_[kMaxNumChunks];
  26 };
  27
  28 // Much less restricted LargeMmapAllocator chunks list (comparing to
  29 // PtrArrayStatic). Backed by mmaped memory region and can hold up to 1M chunks.
  30 // ReservedAddressRange was used instead of just MAP_NORESERVE to achieve the
  31 // same functionality in Fuchsia case, which does not support MAP_NORESERVE.
  32 class LargeMmapAllocatorPtrArrayDynamic {
  33  public:
  34   inline void *Init() {
  35     uptr p = address_range_.Init(kMaxNumChunks * sizeof(uptr),
  36                                  SecondaryAllocatorName);
  37     CHECK(p);
  38     return reinterpret_cast<void*>(p);
  39   }
  40
  41   inline void EnsureSpace(uptr n) {
  42     CHECK_LT(n, kMaxNumChunks);
  43     DCHECK(n <= n_reserved_);
  44     if (UNLIKELY(n == n_reserved_)) {
  45       address_range_.MapOrDie(
  46           reinterpret_cast<uptr>(address_range_.base()) +
  47               n_reserved_ * sizeof(uptr),
  48           kChunksBlockCount * sizeof(uptr));
  49       n_reserved_ += kChunksBlockCount;
  50     }
  51   }
  52
  53  private:
  54   static const int kMaxNumChunks = 1 << 20;
  55   static const int kChunksBlockCount = 1 << 14;
  56   ReservedAddressRange address_range_;
  57   uptr n_reserved_;
  58 };
  59
  60 #if SANITIZER_WORDSIZE == 32
  61 typedef LargeMmapAllocatorPtrArrayStatic DefaultLargeMmapAllocatorPtrArray;
  62 #else
  63 typedef LargeMmapAllocatorPtrArrayDynamic DefaultLargeMmapAllocatorPtrArray;
  64 #endif
  65
  66 // This class can (de)allocate only large chunks of memory using mmap/unmap.
  67 // The main purpose of this allocator is to cover large and rare allocation
  68 // sizes not covered by more efficient allocators (e.g. SizeClassAllocator64).
  69 template <class MapUnmapCallback = NoOpMapUnmapCallback,
  70           class PtrArrayT = DefaultLargeMmapAllocatorPtrArray,
  71           class AddressSpaceViewTy = LocalAddressSpaceView>
  72 class LargeMmapAllocator {
  73  public:
  74   using AddressSpaceView = AddressSpaceViewTy;
  75   void InitLinkerInitialized() {
  76     page_size_ = GetPageSizeCached();
  77     chunks_ = reinterpret_cast<Header**>(ptr_array_.Init());
  78   }
  79
  80   void Init() {
  81     internal_memset(this, 0, sizeof(*this));
  82     InitLinkerInitialized();
  83   }
  84
  85   void *Allocate(AllocatorStats *stat, uptr size, uptr alignment) {
  86     CHECK(IsPowerOfTwo(alignment));
  87     uptr map_size = RoundUpMapSize(size);
  88     if (alignment > page_size_)
  89       map_size += alignment;
  90     // Overflow.
  91     if (map_size < size) {
  92       Report("WARNING: %s: LargeMmapAllocator allocation overflow: "
  93              "0x%zx bytes with 0x%zx alignment requested\n",
  94              SanitizerToolName, map_size, alignment);
  95       return nullptr;
  96     }
  97     uptr map_beg = reinterpret_cast<uptr>(
  98         MmapOrDieOnFatalError(map_size, SecondaryAllocatorName));
  99     if (!map_beg)
 100       return nullptr;
 101     CHECK(IsAligned(map_beg, page_size_));
 102     MapUnmapCallback().OnMap(map_beg, map_size);
 103     uptr map_end = map_beg + map_size;
 104     uptr res = map_beg + page_size_;
 105     if (res & (alignment - 1))  // Align.
 106       res += alignment - (res & (alignment - 1));
 107     CHECK(IsAligned(res, alignment));
 108     CHECK(IsAligned(res, page_size_));
 109     CHECK_GE(res + size, map_beg);
 110     CHECK_LE(res + size, map_end);
 111     Header *h = GetHeader(res);
 112     h->size = size;
 113     h->map_beg = map_beg;
 114     h->map_size = map_size;
 115     uptr size_log = MostSignificantSetBitIndex(map_size);
 116     CHECK_LT(size_log, ARRAY_SIZE(stats.by_size_log));
 117     {
 118       SpinMutexLock l(&mutex_);
 119       ptr_array_.EnsureSpace(n_chunks_);
 120       uptr idx = n_chunks_++;
 121       h->chunk_idx = idx;
 122       chunks_[idx] = h;
 123       chunks_sorted_ = false;
 124       stats.n_allocs++;
 125       stats.currently_allocated += map_size;
 126       stats.max_allocated = Max(stats.max_allocated, stats.currently_allocated);
 127       stats.by_size_log[size_log]++;
 128       stat->Add(AllocatorStatAllocated, map_size);
 129       stat->Add(AllocatorStatMapped, map_size);
 130     }
 131     return reinterpret_cast<void*>(res);
 132   }
 133
 134   void Deallocate(AllocatorStats *stat, void *p) {
 135     Header *h = GetHeader(p);
 136     {
 137       SpinMutexLock l(&mutex_);
 138       uptr idx = h->chunk_idx;
 139       CHECK_EQ(chunks_[idx], h);
 140       CHECK_LT(idx, n_chunks_);
 141       chunks_[idx] = chunks_[--n_chunks_];
 142       chunks_[idx]->chunk_idx = idx;
 143       chunks_sorted_ = false;
 144       stats.n_frees++;
 145       stats.currently_allocated -= h->map_size;
 146       stat->Sub(AllocatorStatAllocated, h->map_size);
 147       stat->Sub(AllocatorStatMapped, h->map_size);
 148     }
 149     MapUnmapCallback().OnUnmap(h->map_beg, h->map_size);
 150     UnmapOrDie(reinterpret_cast<void*>(h->map_beg), h->map_size);
 151   }
 152
 153   uptr TotalMemoryUsed() {
 154     SpinMutexLock l(&mutex_);
 155     uptr res = 0;
 156     for (uptr i = 0; i < n_chunks_; i++) {
 157       Header *h = chunks_[i];
 158       CHECK_EQ(h->chunk_idx, i);
 159       res += RoundUpMapSize(h->size);
 160     }
 161     return res;
 162   }
 163
 164   bool PointerIsMine(const void *p) const {
 165     return GetBlockBegin(p) != nullptr;
 166   }
 167
 168   uptr GetActuallyAllocatedSize(void *p) {
 169     return RoundUpTo(GetHeader(p)->size, page_size_);
 170   }
 171
 172   // At least page_size_/2 metadata bytes is available.
 173   void *GetMetaData(const void *p) {
 174     // Too slow: CHECK_EQ(p, GetBlockBegin(p));
 175     if (!IsAligned(reinterpret_cast<uptr>(p), page_size_)) {
 176       Printf("%s: bad pointer %p\n", SanitizerToolName, p);
 177       CHECK(IsAligned(reinterpret_cast<uptr>(p), page_size_));
 178     }
 179     return GetHeader(p) + 1;
 180   }
 181
 182   void *GetBlockBegin(const void *ptr) const {
 183     uptr p = reinterpret_cast<uptr>(ptr);
 184     SpinMutexLock l(&mutex_);
 185     uptr nearest_chunk = 0;
 186     Header *const *chunks = AddressSpaceView::Load(chunks_, n_chunks_);
 187     // Cache-friendly linear search.
 188     for (uptr i = 0; i < n_chunks_; i++) {
 189       uptr ch = reinterpret_cast<uptr>(chunks[i]);
 190       if (p < ch) continue;  // p is at left to this chunk, skip it.
 191       if (p - ch < p - nearest_chunk)
 192         nearest_chunk = ch;
 193     }
 194     if (!nearest_chunk)
 195       return nullptr;
 196     const Header *h =
 197         AddressSpaceView::Load(reinterpret_cast<Header *>(nearest_chunk));
 198     Header *h_ptr = reinterpret_cast<Header *>(nearest_chunk);
 199     CHECK_GE(nearest_chunk, h->map_beg);
 200     CHECK_LT(nearest_chunk, h->map_beg + h->map_size);
 201     CHECK_LE(nearest_chunk, p);
 202     if (h->map_beg + h->map_size <= p)
 203       return nullptr;
 204     return GetUser(h_ptr);
 205   }
 206
 207   void EnsureSortedChunks() {
 208     if (chunks_sorted_) return;
 209     Header **chunks = AddressSpaceView::LoadWritable(chunks_, n_chunks_);
 210     Sort(reinterpret_cast<uptr *>(chunks), n_chunks_);
 211     for (uptr i = 0; i < n_chunks_; i++)
 212       AddressSpaceView::LoadWritable(chunks[i])->chunk_idx = i;
 213     chunks_sorted_ = true;
 214   }
 215
 216   // This function does the same as GetBlockBegin, but is much faster.
 217   // Must be called with the allocator locked.
 218   void *GetBlockBeginFastLocked(const void *ptr) {
 219     mutex_.CheckLocked();
 220     uptr p = reinterpret_cast<uptr>(ptr);
 221     uptr n = n_chunks_;
 222     if (!n) return nullptr;
 223     EnsureSortedChunks();
 224     Header *const *chunks = AddressSpaceView::Load(chunks_, n_chunks_);
 225     auto min_mmap_ = reinterpret_cast<uptr>(chunks[0]);
 226     auto max_mmap_ = reinterpret_cast<uptr>(chunks[n - 1]) +
 227                      AddressSpaceView::Load(chunks[n - 1])->map_size;
 228     if (p < min_mmap_ || p >= max_mmap_)
 229       return nullptr;
 230     uptr beg = 0, end = n - 1;
 231     // This loop is a log(n) lower_bound. It does not check for the exact match
 232     // to avoid expensive cache-thrashing loads.
 233     while (end - beg >= 2) {
 234       uptr mid = (beg + end) / 2;  // Invariant: mid >= beg + 1
 235       if (p < reinterpret_cast<uptr>(chunks[mid]))
 236         end = mid - 1;  // We are not interested in chunks[mid].
 237       else
 238         beg = mid;  // chunks[mid] may still be what we want.
 239     }
 240
 241     if (beg < end) {
 242       CHECK_EQ(beg + 1, end);
 243       // There are 2 chunks left, choose one.
 244       if (p >= reinterpret_cast<uptr>(chunks[end]))
 245         beg = end;
 246     }
 247
 248     const Header *h = AddressSpaceView::Load(chunks[beg]);
 249     Header *h_ptr = chunks[beg];
 250     if (h->map_beg + h->map_size <= p || p < h->map_beg)
 251       return nullptr;
 252     return GetUser(h_ptr);
 253   }
 254
 255   void PrintStats() {
 256     Printf("Stats: LargeMmapAllocator: allocated %zd times, "
 257            "remains %zd (%zd K) max %zd M; by size logs: ",
 258            stats.n_allocs, stats.n_allocs - stats.n_frees,
 259            stats.currently_allocated >> 10, stats.max_allocated >> 20);
 260     for (uptr i = 0; i < ARRAY_SIZE(stats.by_size_log); i++) {
 261       uptr c = stats.by_size_log[i];
 262       if (!c) continue;
 263       Printf("%zd:%zd; ", i, c);
 264     }
 265     Printf("\n");
 266   }
 267
 268   // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
 269   // introspection API.
 270   void ForceLock() SANITIZER_ACQUIRE(mutex_) { mutex_.Lock(); }
 271
 272   void ForceUnlock() SANITIZER_RELEASE(mutex_) { mutex_.Unlock(); }
 273
 274   // Iterate over all existing chunks.
 275   // The allocator must be locked when calling this function.
 276   void ForEachChunk(ForEachChunkCallback callback, void *arg) {
 277     EnsureSortedChunks();  // Avoid doing the sort while iterating.
 278     const Header *const *chunks = AddressSpaceView::Load(chunks_, n_chunks_);
 279     for (uptr i = 0; i < n_chunks_; i++) {
 280       const Header *t = chunks[i];
 281       callback(reinterpret_cast<uptr>(GetUser(t)), arg);
 282       // Consistency check: verify that the array did not change.
 283       CHECK_EQ(chunks[i], t);
 284       CHECK_EQ(AddressSpaceView::Load(chunks[i])->chunk_idx, i);
 285     }
 286   }
 287
 288  private:
 289   struct Header {
 290     uptr map_beg;
 291     uptr map_size;
 292     uptr size;
 293     uptr chunk_idx;
 294   };
 295
 296   Header *GetHeader(uptr p) {
 297     CHECK(IsAligned(p, page_size_));
 298     return reinterpret_cast<Header*>(p - page_size_);
 299   }
 300   Header *GetHeader(const void *p) {
 301     return GetHeader(reinterpret_cast<uptr>(p));
 302   }
 303
 304   void *GetUser(const Header *h) const {
 305     CHECK(IsAligned((uptr)h, page_size_));
 306     return reinterpret_cast<void*>(reinterpret_cast<uptr>(h) + page_size_);
 307   }
 308
 309   uptr RoundUpMapSize(uptr size) {
 310     return RoundUpTo(size, page_size_) + page_size_;
 311   }
 312
 313   uptr page_size_;
 314   Header **chunks_;
 315   PtrArrayT ptr_array_;
 316   uptr n_chunks_;
 317   bool chunks_sorted_;
 318   struct Stats {
 319     uptr n_allocs, n_frees, currently_allocated, max_allocated, by_size_log[64];
 320   } stats;
 321   mutable StaticSpinMutex mutex_;
 322 };