Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 1378 insertions, 0 deletions

diff --git a/gcc-4.9/libsanitizer/sanitizer_common/sanitizer_allocator.h b/gcc-4.9/libsanitizer/sanitizer_common/sanitizer_allocator.h
new file mode 100644
index 000000000..8ba825f14
--- /dev/null
+++ b/gcc-4.9/libsanitizer/sanitizer_common/sanitizer_allocator.h
@@ -0,0 +1,1378 @@
+//===-- sanitizer_allocator.h -----------------------------------*- C++ -*-===//
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Specialized memory allocator for ThreadSanitizer, MemorySanitizer, etc.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SANITIZER_ALLOCATOR_H
+#define SANITIZER_ALLOCATOR_H
+
+#include "sanitizer_internal_defs.h"
+#include "sanitizer_common.h"
+#include "sanitizer_libc.h"
+#include "sanitizer_list.h"
+#include "sanitizer_mutex.h"
+#include "sanitizer_lfstack.h"
+
+namespace __sanitizer {
+
+// Depending on allocator_may_return_null either return 0 or crash.
+void *AllocatorReturnNull();
+
+// SizeClassMap maps allocation sizes into size classes and back.
+// Class 0 corresponds to size 0.
+// Classes 1 - 16 correspond to sizes 16 to 256 (size = class_id * 16).
+// Next 4 classes: 256 + i * 64  (i = 1 to 4).
+// Next 4 classes: 512 + i * 128 (i = 1 to 4).
+// ...
+// Next 4 classes: 2^k + i * 2^(k-2) (i = 1 to 4).
+// Last class corresponds to kMaxSize = 1 << kMaxSizeLog.
+//
+// This structure of the size class map gives us:
+//   - Efficient table-free class-to-size and size-to-class functions.
+//   - Difference between two consequent size classes is betweed 14% and 25%
+//
+// This class also gives a hint to a thread-caching allocator about the amount
+// of chunks that need to be cached per-thread:
+//  - kMaxNumCached is the maximal number of chunks per size class.
+//  - (1 << kMaxBytesCachedLog) is the maximal number of bytes per size class.
+//
+// Part of output of SizeClassMap::Print():
+// c00 => s: 0 diff: +0 00% l 0 cached: 0 0; id 0
+// c01 => s: 16 diff: +16 00% l 4 cached: 256 4096; id 1
+// c02 => s: 32 diff: +16 100% l 5 cached: 256 8192; id 2
+// c03 => s: 48 diff: +16 50% l 5 cached: 256 12288; id 3
+// c04 => s: 64 diff: +16 33% l 6 cached: 256 16384; id 4
+// c05 => s: 80 diff: +16 25% l 6 cached: 256 20480; id 5
+// c06 => s: 96 diff: +16 20% l 6 cached: 256 24576; id 6
+// c07 => s: 112 diff: +16 16% l 6 cached: 256 28672; id 7
+//
+// c08 => s: 128 diff: +16 14% l 7 cached: 256 32768; id 8
+// c09 => s: 144 diff: +16 12% l 7 cached: 256 36864; id 9
+// c10 => s: 160 diff: +16 11% l 7 cached: 256 40960; id 10
+// c11 => s: 176 diff: +16 10% l 7 cached: 256 45056; id 11
+// c12 => s: 192 diff: +16 09% l 7 cached: 256 49152; id 12
+// c13 => s: 208 diff: +16 08% l 7 cached: 256 53248; id 13
+// c14 => s: 224 diff: +16 07% l 7 cached: 256 57344; id 14
+// c15 => s: 240 diff: +16 07% l 7 cached: 256 61440; id 15
+//
+// c16 => s: 256 diff: +16 06% l 8 cached: 256 65536; id 16
+// c17 => s: 320 diff: +64 25% l 8 cached: 204 65280; id 17
+// c18 => s: 384 diff: +64 20% l 8 cached: 170 65280; id 18
+// c19 => s: 448 diff: +64 16% l 8 cached: 146 65408; id 19
+//
+// c20 => s: 512 diff: +64 14% l 9 cached: 128 65536; id 20
+// c21 => s: 640 diff: +128 25% l 9 cached: 102 65280; id 21
+// c22 => s: 768 diff: +128 20% l 9 cached: 85 65280; id 22
+// c23 => s: 896 diff: +128 16% l 9 cached: 73 65408; id 23
+//
+// c24 => s: 1024 diff: +128 14% l 10 cached: 64 65536; id 24
+// c25 => s: 1280 diff: +256 25% l 10 cached: 51 65280; id 25
+// c26 => s: 1536 diff: +256 20% l 10 cached: 42 64512; id 26
+// c27 => s: 1792 diff: +256 16% l 10 cached: 36 64512; id 27
+//
+// ...
+//
+// c48 => s: 65536 diff: +8192 14% l 16 cached: 1 65536; id 48
+// c49 => s: 81920 diff: +16384 25% l 16 cached: 1 81920; id 49
+// c50 => s: 98304 diff: +16384 20% l 16 cached: 1 98304; id 50
+// c51 => s: 114688 diff: +16384 16% l 16 cached: 1 114688; id 51
+//
+// c52 => s: 131072 diff: +16384 14% l 17 cached: 1 131072; id 52
+
+template <uptr kMaxSizeLog, uptr kMaxNumCachedT, uptr kMaxBytesCachedLog>
+class SizeClassMap {
+  static const uptr kMinSizeLog = 4;
+  static const uptr kMidSizeLog = kMinSizeLog + 4;
+  static const uptr kMinSize = 1 << kMinSizeLog;
+  static const uptr kMidSize = 1 << kMidSizeLog;
+  static const uptr kMidClass = kMidSize / kMinSize;
+  static const uptr S = 2;
+  static const uptr M = (1 << S) - 1;
+
+ public:
+  static const uptr kMaxNumCached = kMaxNumCachedT;
+  // We transfer chunks between central and thread-local free lists in batches.
+  // For small size classes we allocate batches separately.
+  // For large size classes we use one of the chunks to store the batch.
+  struct TransferBatch {
+    TransferBatch *next;
+    uptr count;
+    void *batch[kMaxNumCached];
+  };
+
+  static const uptr kMaxSize = 1UL << kMaxSizeLog;
+  static const uptr kNumClasses =
+      kMidClass + ((kMaxSizeLog - kMidSizeLog) << S) + 1;
+  COMPILER_CHECK(kNumClasses >= 32 && kNumClasses <= 256);
+  static const uptr kNumClassesRounded =
+      kNumClasses == 32  ? 32 :
+      kNumClasses <= 64  ? 64 :
+      kNumClasses <= 128 ? 128 : 256;
+
+  static uptr Size(uptr class_id) {
+    if (class_id <= kMidClass)
+      return kMinSize * class_id;
+    class_id -= kMidClass;
+    uptr t = kMidSize << (class_id >> S);
+    return t + (t >> S) * (class_id & M);
+  }
+
+  static uptr ClassID(uptr size) {
+    if (size <= kMidSize)
+      return (size + kMinSize - 1) >> kMinSizeLog;
+    if (size > kMaxSize) return 0;
+    uptr l = MostSignificantSetBitIndex(size);
+    uptr hbits = (size >> (l - S)) & M;
+    uptr lbits = size & ((1 << (l - S)) - 1);
+    uptr l1 = l - kMidSizeLog;
+    return kMidClass + (l1 << S) + hbits + (lbits > 0);
+  }
+
+  static uptr MaxCached(uptr class_id) {
+    if (class_id == 0) return 0;
+    uptr n = (1UL << kMaxBytesCachedLog) / Size(class_id);
+    return Max<uptr>(1, Min(kMaxNumCached, n));
+  }
+
+  static void Print() {
+    uptr prev_s = 0;
+    uptr total_cached = 0;
+    for (uptr i = 0; i < kNumClasses; i++) {
+      uptr s = Size(i);
+      if (s >= kMidSize / 2 && (s & (s - 1)) == 0)
+        Printf("\n");
+      uptr d = s - prev_s;
+      uptr p = prev_s ? (d * 100 / prev_s) : 0;
+      uptr l = s ? MostSignificantSetBitIndex(s) : 0;
+      uptr cached = MaxCached(i) * s;
+      Printf("c%02zd => s: %zd diff: +%zd %02zd%% l %zd "
+             "cached: %zd %zd; id %zd\n",
+             i, Size(i), d, p, l, MaxCached(i), cached, ClassID(s));
+      total_cached += cached;
+      prev_s = s;
+    }
+    Printf("Total cached: %zd\n", total_cached);
+  }
+
+  static bool SizeClassRequiresSeparateTransferBatch(uptr class_id) {
+    return Size(class_id) < sizeof(TransferBatch) -
+        sizeof(uptr) * (kMaxNumCached - MaxCached(class_id));
+  }
+
+  static void Validate() {
+    for (uptr c = 1; c < kNumClasses; c++) {
+      // Printf("Validate: c%zd\n", c);
+      uptr s = Size(c);
+      CHECK_NE(s, 0U);
+      CHECK_EQ(ClassID(s), c);
+      if (c != kNumClasses - 1)
+        CHECK_EQ(ClassID(s + 1), c + 1);
+      CHECK_EQ(ClassID(s - 1), c);
+      if (c)
+        CHECK_GT(Size(c), Size(c-1));
+    }
+    CHECK_EQ(ClassID(kMaxSize + 1), 0);
+
+    for (uptr s = 1; s <= kMaxSize; s++) {
+      uptr c = ClassID(s);
+      // Printf("s%zd => c%zd\n", s, c);
+      CHECK_LT(c, kNumClasses);
+      CHECK_GE(Size(c), s);
+      if (c > 0)
+        CHECK_LT(Size(c-1), s);
+    }
+  }
+};
+
+typedef SizeClassMap<17, 128, 16> DefaultSizeClassMap;
+typedef SizeClassMap<17, 64,  14> CompactSizeClassMap;
+template<class SizeClassAllocator> struct SizeClassAllocatorLocalCache;
+
+// Memory allocator statistics
+enum AllocatorStat {
+  AllocatorStatMalloced,
+  AllocatorStatFreed,
+  AllocatorStatMmapped,
+  AllocatorStatUnmapped,
+  AllocatorStatCount
+};
+
+typedef u64 AllocatorStatCounters[AllocatorStatCount];
+
+// Per-thread stats, live in per-thread cache.
+class AllocatorStats {
+ public:
+  void Init() {
+    internal_memset(this, 0, sizeof(*this));
+  }
+
+  void Add(AllocatorStat i, u64 v) {
+    v += atomic_load(&stats_[i], memory_order_relaxed);
+    atomic_store(&stats_[i], v, memory_order_relaxed);
+  }
+
+  void Set(AllocatorStat i, u64 v) {
+    atomic_store(&stats_[i], v, memory_order_relaxed);
+  }
+
+  u64 Get(AllocatorStat i) const {
+    return atomic_load(&stats_[i], memory_order_relaxed);
+  }
+
+ private:
+  friend class AllocatorGlobalStats;
+  AllocatorStats *next_;
+  AllocatorStats *prev_;
+  atomic_uint64_t stats_[AllocatorStatCount];
+};
+
+// Global stats, used for aggregation and querying.
+class AllocatorGlobalStats : public AllocatorStats {
+ public:
+  void Init() {
+    internal_memset(this, 0, sizeof(*this));
+    next_ = this;
+    prev_ = this;
+  }
+
+  void Register(AllocatorStats *s) {
+    SpinMutexLock l(&mu_);
+    s->next_ = next_;
+    s->prev_ = this;
+    next_->prev_ = s;
+    next_ = s;
+  }
+
+  void Unregister(AllocatorStats *s) {
+    SpinMutexLock l(&mu_);
+    s->prev_->next_ = s->next_;
+    s->next_->prev_ = s->prev_;
+    for (int i = 0; i < AllocatorStatCount; i++)
+      Add(AllocatorStat(i), s->Get(AllocatorStat(i)));
+  }
+
+  void Get(AllocatorStatCounters s) const {
+    internal_memset(s, 0, AllocatorStatCount * sizeof(u64));
+    SpinMutexLock l(&mu_);
+    const AllocatorStats *stats = this;
+    for (;;) {
+      for (int i = 0; i < AllocatorStatCount; i++)
+        s[i] += stats->Get(AllocatorStat(i));
+      stats = stats->next_;
+      if (stats == this)
+        break;
+    }
+  }
+
+ private:
+  mutable SpinMutex mu_;
+};
+
+// Allocators call these callbacks on mmap/munmap.
+struct NoOpMapUnmapCallback {
+  void OnMap(uptr p, uptr size) const { }
+  void OnUnmap(uptr p, uptr size) const { }
+};
+
+// Callback type for iterating over chunks.
+typedef void (*ForEachChunkCallback)(uptr chunk, void *arg);
+
+// SizeClassAllocator64 -- allocator for 64-bit address space.
+//
+// Space: a portion of address space of kSpaceSize bytes starting at
+// a fixed address (kSpaceBeg). Both constants are powers of two and
+// kSpaceBeg is kSpaceSize-aligned.
+// At the beginning the entire space is mprotect-ed, then small parts of it
+// are mapped on demand.
+//
+// Region: a part of Space dedicated to a single size class.
+// There are kNumClasses Regions of equal size.
+//
+// UserChunk: a piece of memory returned to user.
+// MetaChunk: kMetadataSize bytes of metadata associated with a UserChunk.
+//
+// A Region looks like this:
+// UserChunk1 ... UserChunkN <gap> MetaChunkN ... MetaChunk1
+template <const uptr kSpaceBeg, const uptr kSpaceSize,
+          const uptr kMetadataSize, class SizeClassMap,
+          class MapUnmapCallback = NoOpMapUnmapCallback>
+class SizeClassAllocator64 {
+ public:
+  typedef typename SizeClassMap::TransferBatch Batch;
+  typedef SizeClassAllocator64<kSpaceBeg, kSpaceSize, kMetadataSize,
+      SizeClassMap, MapUnmapCallback> ThisT;
+  typedef SizeClassAllocatorLocalCache<ThisT> AllocatorCache;
+
+  void Init() {
+    CHECK_EQ(kSpaceBeg,
+             reinterpret_cast<uptr>(Mprotect(kSpaceBeg, kSpaceSize)));
+    MapWithCallback(kSpaceEnd, AdditionalSize());
+  }
+
+  void MapWithCallback(uptr beg, uptr size) {
+    CHECK_EQ(beg, reinterpret_cast<uptr>(MmapFixedOrDie(beg, size)));
+    MapUnmapCallback().OnMap(beg, size);
+  }
+
+  void UnmapWithCallback(uptr beg, uptr size) {
+    MapUnmapCallback().OnUnmap(beg, size);
+    UnmapOrDie(reinterpret_cast<void *>(beg), size);
+  }
+
+  static bool CanAllocate(uptr size, uptr alignment) {
+    return size <= SizeClassMap::kMaxSize &&
+      alignment <= SizeClassMap::kMaxSize;
+  }
+
+  NOINLINE Batch* AllocateBatch(AllocatorStats *stat, AllocatorCache *c,
+                                uptr class_id) {
+    CHECK_LT(class_id, kNumClasses);
+    RegionInfo *region = GetRegionInfo(class_id);
+    Batch *b = region->free_list.Pop();
+    if (b == 0)
+      b = PopulateFreeList(stat, c, class_id, region);
+    region->n_allocated += b->count;
+    return b;
+  }
+
+  NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id, Batch *b) {
+    RegionInfo *region = GetRegionInfo(class_id);
+    CHECK_GT(b->count, 0);
+    region->free_list.Push(b);
+    region->n_freed += b->count;
+  }
+
+  static bool PointerIsMine(const void *p) {
+    return reinterpret_cast<uptr>(p) / kSpaceSize == kSpaceBeg / kSpaceSize;
+  }
+
+  static uptr GetSizeClass(const void *p) {
+    return (reinterpret_cast<uptr>(p) / kRegionSize) % kNumClassesRounded;
+  }
+
+  void *GetBlockBegin(const void *p) {
+    uptr class_id = GetSizeClass(p);
+    uptr size = SizeClassMap::Size(class_id);
+    if (!size) return 0;
+    uptr chunk_idx = GetChunkIdx((uptr)p, size);
+    uptr reg_beg = (uptr)p & ~(kRegionSize - 1);
+    uptr beg = chunk_idx * size;
+    uptr next_beg = beg + size;
+    if (class_id >= kNumClasses) return 0;
+    RegionInfo *region = GetRegionInfo(class_id);
+    if (region->mapped_user >= next_beg)
+      return reinterpret_cast<void*>(reg_beg + beg);
+    return 0;
+  }
+
+  static uptr GetActuallyAllocatedSize(void *p) {
+    CHECK(PointerIsMine(p));
+    return SizeClassMap::Size(GetSizeClass(p));
+  }
+
+  uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
+
+  void *GetMetaData(const void *p) {
+    uptr class_id = GetSizeClass(p);
+    uptr size = SizeClassMap::Size(class_id);
+    uptr chunk_idx = GetChunkIdx(reinterpret_cast<uptr>(p), size);
+    return reinterpret_cast<void*>(kSpaceBeg + (kRegionSize * (class_id + 1)) -
+                                   (1 + chunk_idx) * kMetadataSize);
+  }
+
+  uptr TotalMemoryUsed() {
+    uptr res = 0;
+    for (uptr i = 0; i < kNumClasses; i++)
+      res += GetRegionInfo(i)->allocated_user;
+    return res;
+  }
+
+  // Test-only.
+  void TestOnlyUnmap() {
+    UnmapWithCallback(kSpaceBeg, kSpaceSize + AdditionalSize());
+  }
+
+  void PrintStats() {
+    uptr total_mapped = 0;
+    uptr n_allocated = 0;
+    uptr n_freed = 0;
+    for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
+      RegionInfo *region = GetRegionInfo(class_id);
+      total_mapped += region->mapped_user;
+      n_allocated += region->n_allocated;
+      n_freed += region->n_freed;
+    }
+    Printf("Stats: SizeClassAllocator64: %zdM mapped in %zd allocations; "
+           "remains %zd\n",
+           total_mapped >> 20, n_allocated, n_allocated - n_freed);
+    for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
+      RegionInfo *region = GetRegionInfo(class_id);
+      if (region->mapped_user == 0) continue;
+      Printf("  %02zd (%zd): total: %zd K allocs: %zd remains: %zd\n",
+             class_id,
+             SizeClassMap::Size(class_id),
+             region->mapped_user >> 10,
+             region->n_allocated,
+             region->n_allocated - region->n_freed);
+    }
+  }
+
+  // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
+  // introspection API.
+  void ForceLock() {
+    for (uptr i = 0; i < kNumClasses; i++) {
+      GetRegionInfo(i)->mutex.Lock();
+    }
+  }
+
+  void ForceUnlock() {
+    for (int i = (int)kNumClasses - 1; i >= 0; i--) {
+      GetRegionInfo(i)->mutex.Unlock();
+    }
+  }
+
+  // Iterate over all existing chunks.
+  // The allocator must be locked when calling this function.
+  void ForEachChunk(ForEachChunkCallback callback, void *arg) {
+    for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
+      RegionInfo *region = GetRegionInfo(class_id);
+      uptr chunk_size = SizeClassMap::Size(class_id);
+      uptr region_beg = kSpaceBeg + class_id * kRegionSize;
+      for (uptr chunk = region_beg;
+           chunk < region_beg + region->allocated_user;
+           chunk += chunk_size) {
+        // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
+        callback(chunk, arg);
+      }
+    }
+  }
+
+  typedef SizeClassMap SizeClassMapT;
+  static const uptr kNumClasses = SizeClassMap::kNumClasses;
+  static const uptr kNumClassesRounded = SizeClassMap::kNumClassesRounded;
+
+ private:
+  static const uptr kRegionSize = kSpaceSize / kNumClassesRounded;
+  static const uptr kSpaceEnd = kSpaceBeg + kSpaceSize;
+  COMPILER_CHECK(kSpaceBeg % kSpaceSize == 0);
+  // kRegionSize must be >= 2^32.
+  COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2)));
+  // Populate the free list with at most this number of bytes at once
+  // or with one element if its size is greater.
+  static const uptr kPopulateSize = 1 << 14;
+  // Call mmap for user memory with at least this size.
+  static const uptr kUserMapSize = 1 << 16;
+  // Call mmap for metadata memory with at least this size.
+  static const uptr kMetaMapSize = 1 << 16;
+
+  struct RegionInfo {
+    BlockingMutex mutex;
+    LFStack<Batch> free_list;
+    uptr allocated_user;  // Bytes allocated for user memory.
+    uptr allocated_meta;  // Bytes allocated for metadata.
+    uptr mapped_user;  // Bytes mapped for user memory.
+    uptr mapped_meta;  // Bytes mapped for metadata.
+    uptr n_allocated, n_freed;  // Just stats.
+  };
+  COMPILER_CHECK(sizeof(RegionInfo) >= kCacheLineSize);
+
+  static uptr AdditionalSize() {
+    return RoundUpTo(sizeof(RegionInfo) * kNumClassesRounded,
+                     GetPageSizeCached());
+  }
+
+  RegionInfo *GetRegionInfo(uptr class_id) {
+    CHECK_LT(class_id, kNumClasses);
+    RegionInfo *regions = reinterpret_cast<RegionInfo*>(kSpaceBeg + kSpaceSize);
+    return &regions[class_id];
+  }
+
+  static uptr GetChunkIdx(uptr chunk, uptr size) {
+    uptr offset = chunk % kRegionSize;
+    // Here we divide by a non-constant. This is costly.
+    // size always fits into 32-bits. If the offset fits too, use 32-bit div.
+    if (offset >> (SANITIZER_WORDSIZE / 2))
+      return offset / size;
+    return (u32)offset / (u32)size;
+  }
+
+  NOINLINE Batch* PopulateFreeList(AllocatorStats *stat, AllocatorCache *c,
+                                   uptr class_id, RegionInfo *region) {
+    BlockingMutexLock l(&region->mutex);
+    Batch *b = region->free_list.Pop();
+    if (b)
+      return b;
+    uptr size = SizeClassMap::Size(class_id);
+    uptr count = size < kPopulateSize ? SizeClassMap::MaxCached(class_id) : 1;
+    uptr beg_idx = region->allocated_user;
+    uptr end_idx = beg_idx + count * size;
+    uptr region_beg = kSpaceBeg + kRegionSize * class_id;
+    if (end_idx + size > region->mapped_user) {
+      // Do the mmap for the user memory.
+      uptr map_size = kUserMapSize;
+      while (end_idx + size > region->mapped_user + map_size)
+        map_size += kUserMapSize;
+      CHECK_GE(region->mapped_user + map_size, end_idx);
+      MapWithCallback(region_beg + region->mapped_user, map_size);
+      stat->Add(AllocatorStatMmapped, map_size);
+      region->mapped_user += map_size;
+    }
+    uptr total_count = (region->mapped_user - beg_idx - size)
+        / size / count * count;
+    region->allocated_meta += total_count * kMetadataSize;
+    if (region->allocated_meta > region->mapped_meta) {
+      uptr map_size = kMetaMapSize;
+      while (region->allocated_meta > region->mapped_meta + map_size)
+        map_size += kMetaMapSize;
+      // Do the mmap for the metadata.
+      CHECK_GE(region->mapped_meta + map_size, region->allocated_meta);
+      MapWithCallback(region_beg + kRegionSize -
+                      region->mapped_meta - map_size, map_size);
+      region->mapped_meta += map_size;
+    }
+    CHECK_LE(region->allocated_meta, region->mapped_meta);
+    if (region->mapped_user + region->mapped_meta > kRegionSize) {
+      Printf("%s: Out of memory. Dying. ", SanitizerToolName);
+      Printf("The process has exhausted %zuMB for size class %zu.\n",
+          kRegionSize / 1024 / 1024, size);
+      Die();
+    }
+    for (;;) {
+      if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
+        b = (Batch*)c->Allocate(this, SizeClassMap::ClassID(sizeof(Batch)));
+      else
+        b = (Batch*)(region_beg + beg_idx);
+      b->count = count;
+      for (uptr i = 0; i < count; i++)
+        b->batch[i] = (void*)(region_beg + beg_idx + i * size);
+      region->allocated_user += count * size;
+      CHECK_LE(region->allocated_user, region->mapped_user);
+      beg_idx += count * size;
+      if (beg_idx + count * size + size > region->mapped_user)
+        break;
+      CHECK_GT(b->count, 0);
+      region->free_list.Push(b);
+    }
+    return b;
+  }
+};
+
+// Maps integers in rage [0, kSize) to u8 values.
+template<u64 kSize>
+class FlatByteMap {
+ public:
+  void TestOnlyInit() {
+    internal_memset(map_, 0, sizeof(map_));
+  }
+
+  void set(uptr idx, u8 val) {
+    CHECK_LT(idx, kSize);
+    CHECK_EQ(0U, map_[idx]);
+    map_[idx] = val;
+  }
+  u8 operator[] (uptr idx) {
+    CHECK_LT(idx, kSize);
+    // FIXME: CHECK may be too expensive here.
+    return map_[idx];
+  }
+ private:
+  u8 map_[kSize];
+};
+
+// TwoLevelByteMap maps integers in range [0, kSize1*kSize2) to u8 values.
+// It is implemented as a two-dimensional array: array of kSize1 pointers
+// to kSize2-byte arrays. The secondary arrays are mmaped on demand.
+// Each value is initially zero and can be set to something else only once.
+// Setting and getting values from multiple threads is safe w/o extra locking.
+template <u64 kSize1, u64 kSize2, class MapUnmapCallback = NoOpMapUnmapCallback>
+class TwoLevelByteMap {
+ public:
+  void TestOnlyInit() {
+    internal_memset(map1_, 0, sizeof(map1_));
+    mu_.Init();
+  }
+  void TestOnlyUnmap() {
+    for (uptr i = 0; i < kSize1; i++) {
+      u8 *p = Get(i);
+      if (!p) continue;
+      MapUnmapCallback().OnUnmap(reinterpret_cast<uptr>(p), kSize2);
+      UnmapOrDie(p, kSize2);
+    }
+  }
+
+  uptr size() const { return kSize1 * kSize2; }
+  uptr size1() const { return kSize1; }
+  uptr size2() const { return kSize2; }
+
+  void set(uptr idx, u8 val) {
+    CHECK_LT(idx, kSize1 * kSize2);
+    u8 *map2 = GetOrCreate(idx / kSize2);
+    CHECK_EQ(0U, map2[idx % kSize2]);
+    map2[idx % kSize2] = val;
+  }
+
+  u8 operator[] (uptr idx) const {
+    CHECK_LT(idx, kSize1 * kSize2);
+    u8 *map2 = Get(idx / kSize2);
+    if (!map2) return 0;
+    return map2[idx % kSize2];
+  }
+
+ private:
+  u8 *Get(uptr idx) const {
+    CHECK_LT(idx, kSize1);
+    return reinterpret_cast<u8 *>(
+        atomic_load(&map1_[idx], memory_order_acquire));
+  }
+
+  u8 *GetOrCreate(uptr idx) {
+    u8 *res = Get(idx);
+    if (!res) {
+      SpinMutexLock l(&mu_);
+      if (!(res = Get(idx))) {
+        res = (u8*)MmapOrDie(kSize2, "TwoLevelByteMap");
+        MapUnmapCallback().OnMap(reinterpret_cast<uptr>(res), kSize2);
+        atomic_store(&map1_[idx], reinterpret_cast<uptr>(res),
+                     memory_order_release);
+      }
+    }
+    return res;
+  }
+
+  atomic_uintptr_t map1_[kSize1];
+  StaticSpinMutex mu_;
+};
+
+// SizeClassAllocator32 -- allocator for 32-bit address space.
+// This allocator can theoretically be used on 64-bit arch, but there it is less
+// efficient than SizeClassAllocator64.
+//
+// [kSpaceBeg, kSpaceBeg + kSpaceSize) is the range of addresses which can
+// be returned by MmapOrDie().
+//
+// Region:
+//   a result of a single call to MmapAlignedOrDie(kRegionSize, kRegionSize).
+// Since the regions are aligned by kRegionSize, there are exactly
+// kNumPossibleRegions possible regions in the address space and so we keep
+// a ByteMap possible_regions to store the size classes of each Region.
+// 0 size class means the region is not used by the allocator.
+//
+// One Region is used to allocate chunks of a single size class.
+// A Region looks like this:
+// UserChunk1 .. UserChunkN <gap> MetaChunkN .. MetaChunk1
+//
+// In order to avoid false sharing the objects of this class should be
+// chache-line aligned.
+template <const uptr kSpaceBeg, const u64 kSpaceSize,
+          const uptr kMetadataSize, class SizeClassMap,
+          const uptr kRegionSizeLog,
+          class ByteMap,
+          class MapUnmapCallback = NoOpMapUnmapCallback>
+class SizeClassAllocator32 {
+ public:
+  typedef typename SizeClassMap::TransferBatch Batch;
+  typedef SizeClassAllocator32<kSpaceBeg, kSpaceSize, kMetadataSize,
+      SizeClassMap, kRegionSizeLog, ByteMap, MapUnmapCallback> ThisT;
+  typedef SizeClassAllocatorLocalCache<ThisT> AllocatorCache;
+
+  void Init() {
+    possible_regions.TestOnlyInit();
+    internal_memset(size_class_info_array, 0, sizeof(size_class_info_array));
+  }
+
+  void *MapWithCallback(uptr size) {
+    size = RoundUpTo(size, GetPageSizeCached());
+    void *res = MmapOrDie(size, "SizeClassAllocator32");
+    MapUnmapCallback().OnMap((uptr)res, size);
+    return res;
+  }
+
+  void UnmapWithCallback(uptr beg, uptr size) {
+    MapUnmapCallback().OnUnmap(beg, size);
+    UnmapOrDie(reinterpret_cast<void *>(beg), size);
+  }
+
+  static bool CanAllocate(uptr size, uptr alignment) {
+    return size <= SizeClassMap::kMaxSize &&
+      alignment <= SizeClassMap::kMaxSize;
+  }
+
+  void *GetMetaData(const void *p) {
+    CHECK(PointerIsMine(p));
+    uptr mem = reinterpret_cast<uptr>(p);
+    uptr beg = ComputeRegionBeg(mem);
+    uptr size = SizeClassMap::Size(GetSizeClass(p));
+    u32 offset = mem - beg;
+    uptr n = offset / (u32)size;  // 32-bit division
+    uptr meta = (beg + kRegionSize) - (n + 1) * kMetadataSize;
+    return reinterpret_cast<void*>(meta);
+  }
+
+  NOINLINE Batch* AllocateBatch(AllocatorStats *stat, AllocatorCache *c,
+                                uptr class_id) {
+    CHECK_LT(class_id, kNumClasses);
+    SizeClassInfo *sci = GetSizeClassInfo(class_id);
+    SpinMutexLock l(&sci->mutex);
+    if (sci->free_list.empty())
+      PopulateFreeList(stat, c, sci, class_id);
+    CHECK(!sci->free_list.empty());
+    Batch *b = sci->free_list.front();
+    sci->free_list.pop_front();
+    return b;
+  }
+
+  NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id, Batch *b) {
+    CHECK_LT(class_id, kNumClasses);
+    SizeClassInfo *sci = GetSizeClassInfo(class_id);
+    SpinMutexLock l(&sci->mutex);
+    CHECK_GT(b->count, 0);
+    sci->free_list.push_front(b);
+  }
+
+  bool PointerIsMine(const void *p) {
+    return GetSizeClass(p) != 0;
+  }
+
+  uptr GetSizeClass(const void *p) {
+    return possible_regions[ComputeRegionId(reinterpret_cast<uptr>(p))];
+  }
+
+  void *GetBlockBegin(const void *p) {
+    CHECK(PointerIsMine(p));
+    uptr mem = reinterpret_cast<uptr>(p);
+    uptr beg = ComputeRegionBeg(mem);
+    uptr size = SizeClassMap::Size(GetSizeClass(p));
+    u32 offset = mem - beg;
+    u32 n = offset / (u32)size;  // 32-bit division
+    uptr res = beg + (n * (u32)size);
+    return reinterpret_cast<void*>(res);
+  }
+
+  uptr GetActuallyAllocatedSize(void *p) {
+    CHECK(PointerIsMine(p));
+    return SizeClassMap::Size(GetSizeClass(p));
+  }
+
+  uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
+
+  uptr TotalMemoryUsed() {
+    // No need to lock here.
+    uptr res = 0;
+    for (uptr i = 0; i < kNumPossibleRegions; i++)
+      if (possible_regions[i])
+        res += kRegionSize;
+    return res;
+  }
+
+  void TestOnlyUnmap() {
+    for (uptr i = 0; i < kNumPossibleRegions; i++)
+      if (possible_regions[i])
+        UnmapWithCallback((i * kRegionSize), kRegionSize);
+  }
+
+  // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
+  // introspection API.
+  void ForceLock() {
+    for (uptr i = 0; i < kNumClasses; i++) {
+      GetSizeClassInfo(i)->mutex.Lock();
+    }
+  }
+
+  void ForceUnlock() {
+    for (int i = kNumClasses - 1; i >= 0; i--) {
+      GetSizeClassInfo(i)->mutex.Unlock();
+    }
+  }
+
+  // Iterate over all existing chunks.
+  // The allocator must be locked when calling this function.
+  void ForEachChunk(ForEachChunkCallback callback, void *arg) {
+    for (uptr region = 0; region < kNumPossibleRegions; region++)
+      if (possible_regions[region]) {
+        uptr chunk_size = SizeClassMap::Size(possible_regions[region]);
+        uptr max_chunks_in_region = kRegionSize / (chunk_size + kMetadataSize);
+        uptr region_beg = region * kRegionSize;
+        for (uptr chunk = region_beg;
+             chunk < region_beg + max_chunks_in_region * chunk_size;
+             chunk += chunk_size) {
+          // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
+          callback(chunk, arg);
+        }
+      }
+  }
+
+  void PrintStats() {
+  }
+
+  typedef SizeClassMap SizeClassMapT;
+  static const uptr kNumClasses = SizeClassMap::kNumClasses;
+
+ private:
+  static const uptr kRegionSize = 1 << kRegionSizeLog;
+  static const uptr kNumPossibleRegions = kSpaceSize / kRegionSize;
+
+  struct SizeClassInfo {
+    SpinMutex mutex;
+    IntrusiveList<Batch> free_list;
+    char padding[kCacheLineSize - sizeof(uptr) - sizeof(IntrusiveList<Batch>)];
+  };
+  COMPILER_CHECK(sizeof(SizeClassInfo) == kCacheLineSize);
+
+  uptr ComputeRegionId(uptr mem) {
+    uptr res = mem >> kRegionSizeLog;
+    CHECK_LT(res, kNumPossibleRegions);
+    return res;
+  }
+
+  uptr ComputeRegionBeg(uptr mem) {
+    return mem & ~(kRegionSize - 1);
+  }
+
+  uptr AllocateRegion(AllocatorStats *stat, uptr class_id) {
+    CHECK_LT(class_id, kNumClasses);
+    uptr res = reinterpret_cast<uptr>(MmapAlignedOrDie(kRegionSize, kRegionSize,
+                                      "SizeClassAllocator32"));
+    MapUnmapCallback().OnMap(res, kRegionSize);
+    stat->Add(AllocatorStatMmapped, kRegionSize);
+    CHECK_EQ(0U, (res & (kRegionSize - 1)));
+    possible_regions.set(ComputeRegionId(res), static_cast<u8>(class_id));
+    return res;
+  }
+
+  SizeClassInfo *GetSizeClassInfo(uptr class_id) {
+    CHECK_LT(class_id, kNumClasses);
+    return &size_class_info_array[class_id];
+  }
+
+  void PopulateFreeList(AllocatorStats *stat, AllocatorCache *c,
+                        SizeClassInfo *sci, uptr class_id) {
+    uptr size = SizeClassMap::Size(class_id);
+    uptr reg = AllocateRegion(stat, class_id);
+    uptr n_chunks = kRegionSize / (size + kMetadataSize);
+    uptr max_count = SizeClassMap::MaxCached(class_id);
+    Batch *b = 0;
+    for (uptr i = reg; i < reg + n_chunks * size; i += size) {
+      if (b == 0) {
+        if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
+          b = (Batch*)c->Allocate(this, SizeClassMap::ClassID(sizeof(Batch)));
+        else
+          b = (Batch*)i;
+        b->count = 0;
+      }
+      b->batch[b->count++] = (void*)i;
+      if (b->count == max_count) {
+        CHECK_GT(b->count, 0);
+        sci->free_list.push_back(b);
+        b = 0;
+      }
+    }
+    if (b) {
+      CHECK_GT(b->count, 0);
+      sci->free_list.push_back(b);
+    }
+  }
+
+  ByteMap possible_regions;
+  SizeClassInfo size_class_info_array[kNumClasses];
+};
+
+// Objects of this type should be used as local caches for SizeClassAllocator64
+// or SizeClassAllocator32. Since the typical use of this class is to have one
+// object per thread in TLS, is has to be POD.
+template<class SizeClassAllocator>
+struct SizeClassAllocatorLocalCache {
+  typedef SizeClassAllocator Allocator;
+  static const uptr kNumClasses = SizeClassAllocator::kNumClasses;
+
+  void Init(AllocatorGlobalStats *s) {
+    stats_.Init();
+    if (s)
+      s->Register(&stats_);
+  }
+
+  void Destroy(SizeClassAllocator *allocator, AllocatorGlobalStats *s) {
+    Drain(allocator);
+    if (s)
+      s->Unregister(&stats_);
+  }
+
+  void *Allocate(SizeClassAllocator *allocator, uptr class_id) {
+    CHECK_NE(class_id, 0UL);
+    CHECK_LT(class_id, kNumClasses);
+    stats_.Add(AllocatorStatMalloced, SizeClassMap::Size(class_id));
+    PerClass *c = &per_class_[class_id];
+    if (UNLIKELY(c->count == 0))
+      Refill(allocator, class_id);
+    void *res = c->batch[--c->count];
+    PREFETCH(c->batch[c->count - 1]);
+    return res;
+  }
+
+  void Deallocate(SizeClassAllocator *allocator, uptr class_id, void *p) {
+    CHECK_NE(class_id, 0UL);
+    CHECK_LT(class_id, kNumClasses);
+    // If the first allocator call on a new thread is a deallocation, then
+    // max_count will be zero, leading to check failure.
+    InitCache();
+    stats_.Add(AllocatorStatFreed, SizeClassMap::Size(class_id));
+    PerClass *c = &per_class_[class_id];
+    CHECK_NE(c->max_count, 0UL);
+    if (UNLIKELY(c->count == c->max_count))
+      Drain(allocator, class_id);
+    c->batch[c->count++] = p;
+  }
+
+  void Drain(SizeClassAllocator *allocator) {
+    for (uptr class_id = 0; class_id < kNumClasses; class_id++) {
+      PerClass *c = &per_class_[class_id];
+      while (c->count > 0)
+        Drain(allocator, class_id);
+    }
+  }
+
+  // private:
+  typedef typename SizeClassAllocator::SizeClassMapT SizeClassMap;
+  typedef typename SizeClassMap::TransferBatch Batch;
+  struct PerClass {
+    uptr count;
+    uptr max_count;
+    void *batch[2 * SizeClassMap::kMaxNumCached];
+  };
+  PerClass per_class_[kNumClasses];
+  AllocatorStats stats_;
+
+  void InitCache() {
+    if (per_class_[1].max_count)
+      return;
+    for (uptr i = 0; i < kNumClasses; i++) {
+      PerClass *c = &per_class_[i];
+      c->max_count = 2 * SizeClassMap::MaxCached(i);
+    }
+  }
+
+  NOINLINE void Refill(SizeClassAllocator *allocator, uptr class_id) {
+    InitCache();
+    PerClass *c = &per_class_[class_id];
+    Batch *b = allocator->AllocateBatch(&stats_, this, class_id);
+    CHECK_GT(b->count, 0);
+    for (uptr i = 0; i < b->count; i++)
+      c->batch[i] = b->batch[i];
+    c->count = b->count;
+    if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
+      Deallocate(allocator, SizeClassMap::ClassID(sizeof(Batch)), b);
+  }
+
+  NOINLINE void Drain(SizeClassAllocator *allocator, uptr class_id) {
+    InitCache();
+    PerClass *c = &per_class_[class_id];
+    Batch *b;
+    if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
+      b = (Batch*)Allocate(allocator, SizeClassMap::ClassID(sizeof(Batch)));
+    else
+      b = (Batch*)c->batch[0];
+    uptr cnt = Min(c->max_count / 2, c->count);
+    for (uptr i = 0; i < cnt; i++) {
+      b->batch[i] = c->batch[i];
+      c->batch[i] = c->batch[i + c->max_count / 2];
+    }
+    b->count = cnt;
+    c->count -= cnt;
+    CHECK_GT(b->count, 0);
+    allocator->DeallocateBatch(&stats_, class_id, b);
+  }
+};
+
+// This class can (de)allocate only large chunks of memory using mmap/unmap.
+// The main purpose of this allocator is to cover large and rare allocation
+// sizes not covered by more efficient allocators (e.g. SizeClassAllocator64).
+template <class MapUnmapCallback = NoOpMapUnmapCallback>
+class LargeMmapAllocator {
+ public:
+  void Init() {
+    internal_memset(this, 0, sizeof(*this));
+    page_size_ = GetPageSizeCached();
+  }
+
+  void *Allocate(AllocatorStats *stat, uptr size, uptr alignment) {
+    CHECK(IsPowerOfTwo(alignment));
+    uptr map_size = RoundUpMapSize(size);
+    if (alignment > page_size_)
+      map_size += alignment;
+    if (map_size < size) return AllocatorReturnNull();  // Overflow.
+    uptr map_beg = reinterpret_cast<uptr>(
+        MmapOrDie(map_size, "LargeMmapAllocator"));
+    MapUnmapCallback().OnMap(map_beg, map_size);
+    uptr map_end = map_beg + map_size;
+    uptr res = map_beg + page_size_;
+    if (res & (alignment - 1))  // Align.
+      res += alignment - (res & (alignment - 1));
+    CHECK_EQ(0, res & (alignment - 1));
+    CHECK_LE(res + size, map_end);
+    Header *h = GetHeader(res);
+    h->size = size;
+    h->map_beg = map_beg;
+    h->map_size = map_size;
+    uptr size_log = MostSignificantSetBitIndex(map_size);
+    CHECK_LT(size_log, ARRAY_SIZE(stats.by_size_log));
+    {
+      SpinMutexLock l(&mutex_);
+      uptr idx = n_chunks_++;
+      chunks_sorted_ = false;
+      CHECK_LT(idx, kMaxNumChunks);
+      h->chunk_idx = idx;
+      chunks_[idx] = h;
+      stats.n_allocs++;
+      stats.currently_allocated += map_size;
+      stats.max_allocated = Max(stats.max_allocated, stats.currently_allocated);
+      stats.by_size_log[size_log]++;
+      stat->Add(AllocatorStatMalloced, map_size);
+      stat->Add(AllocatorStatMmapped, map_size);
+    }
+    return reinterpret_cast<void*>(res);
+  }
+
+  void Deallocate(AllocatorStats *stat, void *p) {
+    Header *h = GetHeader(p);
+    {
+      SpinMutexLock l(&mutex_);
+      uptr idx = h->chunk_idx;
+      CHECK_EQ(chunks_[idx], h);
+      CHECK_LT(idx, n_chunks_);
+      chunks_[idx] = chunks_[n_chunks_ - 1];
+      chunks_[idx]->chunk_idx = idx;
+      n_chunks_--;
+      chunks_sorted_ = false;
+      stats.n_frees++;
+      stats.currently_allocated -= h->map_size;
+      stat->Add(AllocatorStatFreed, h->map_size);
+      stat->Add(AllocatorStatUnmapped, h->map_size);
+    }
+    MapUnmapCallback().OnUnmap(h->map_beg, h->map_size);
+    UnmapOrDie(reinterpret_cast<void*>(h->map_beg), h->map_size);
+  }
+
+  uptr TotalMemoryUsed() {
+    SpinMutexLock l(&mutex_);
+    uptr res = 0;
+    for (uptr i = 0; i < n_chunks_; i++) {
+      Header *h = chunks_[i];
+      CHECK_EQ(h->chunk_idx, i);
+      res += RoundUpMapSize(h->size);
+    }
+    return res;
+  }
+
+  bool PointerIsMine(const void *p) {
+    return GetBlockBegin(p) != 0;
+  }
+
+  uptr GetActuallyAllocatedSize(void *p) {
+    return RoundUpTo(GetHeader(p)->size, page_size_);
+  }
+
+  // At least page_size_/2 metadata bytes is available.
+  void *GetMetaData(const void *p) {
+    // Too slow: CHECK_EQ(p, GetBlockBegin(p));
+    if (!IsAligned(reinterpret_cast<uptr>(p), page_size_)) {
+      Printf("%s: bad pointer %p\n", SanitizerToolName, p);
+      CHECK(IsAligned(reinterpret_cast<uptr>(p), page_size_));
+    }
+    return GetHeader(p) + 1;
+  }
+
+  void *GetBlockBegin(const void *ptr) {
+    uptr p = reinterpret_cast<uptr>(ptr);
+    SpinMutexLock l(&mutex_);
+    uptr nearest_chunk = 0;
+    // Cache-friendly linear search.
+    for (uptr i = 0; i < n_chunks_; i++) {
+      uptr ch = reinterpret_cast<uptr>(chunks_[i]);
+      if (p < ch) continue;  // p is at left to this chunk, skip it.
+      if (p - ch < p - nearest_chunk)
+        nearest_chunk = ch;
+    }
+    if (!nearest_chunk)
+      return 0;
+    Header *h = reinterpret_cast<Header *>(nearest_chunk);
+    CHECK_GE(nearest_chunk, h->map_beg);
+    CHECK_LT(nearest_chunk, h->map_beg + h->map_size);
+    CHECK_LE(nearest_chunk, p);
+    if (h->map_beg + h->map_size <= p)
+      return 0;
+    return GetUser(h);
+  }
+
+  // This function does the same as GetBlockBegin, but is much faster.
+  // Must be called with the allocator locked.
+  void *GetBlockBeginFastLocked(void *ptr) {
+    mutex_.CheckLocked();
+    uptr p = reinterpret_cast<uptr>(ptr);
+    uptr n = n_chunks_;
+    if (!n) return 0;
+    if (!chunks_sorted_) {
+      // Do one-time sort. chunks_sorted_ is reset in Allocate/Deallocate.
+      SortArray(reinterpret_cast<uptr*>(chunks_), n);
+      for (uptr i = 0; i < n; i++)
+        chunks_[i]->chunk_idx = i;
+      chunks_sorted_ = true;
+      min_mmap_ = reinterpret_cast<uptr>(chunks_[0]);
+      max_mmap_ = reinterpret_cast<uptr>(chunks_[n - 1]) +
+          chunks_[n - 1]->map_size;
+    }
+    if (p < min_mmap_ || p >= max_mmap_)
+      return 0;
+    uptr beg = 0, end = n - 1;
+    // This loop is a log(n) lower_bound. It does not check for the exact match
+    // to avoid expensive cache-thrashing loads.
+    while (end - beg >= 2) {
+      uptr mid = (beg + end) / 2;  // Invariant: mid >= beg + 1
+      if (p < reinterpret_cast<uptr>(chunks_[mid]))
+        end = mid - 1;  // We are not interested in chunks_[mid].
+      else
+        beg = mid;  // chunks_[mid] may still be what we want.
+    }
+
+    if (beg < end) {
+      CHECK_EQ(beg + 1, end);
+      // There are 2 chunks left, choose one.
+      if (p >= reinterpret_cast<uptr>(chunks_[end]))
+        beg = end;
+    }
+
+    Header *h = chunks_[beg];
+    if (h->map_beg + h->map_size <= p || p < h->map_beg)
+      return 0;
+    return GetUser(h);
+  }
+
+  void PrintStats() {
+    Printf("Stats: LargeMmapAllocator: allocated %zd times, "
+           "remains %zd (%zd K) max %zd M; by size logs: ",
+           stats.n_allocs, stats.n_allocs - stats.n_frees,
+           stats.currently_allocated >> 10, stats.max_allocated >> 20);
+    for (uptr i = 0; i < ARRAY_SIZE(stats.by_size_log); i++) {
+      uptr c = stats.by_size_log[i];
+      if (!c) continue;
+      Printf("%zd:%zd; ", i, c);
+    }
+    Printf("\n");
+  }
+
+  // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
+  // introspection API.
+  void ForceLock() {
+    mutex_.Lock();
+  }
+
+  void ForceUnlock() {
+    mutex_.Unlock();
+  }
+
+  // Iterate over all existing chunks.
+  // The allocator must be locked when calling this function.
+  void ForEachChunk(ForEachChunkCallback callback, void *arg) {
+    for (uptr i = 0; i < n_chunks_; i++)
+      callback(reinterpret_cast<uptr>(GetUser(chunks_[i])), arg);
+  }
+
+ private:
+  static const int kMaxNumChunks = 1 << FIRST_32_SECOND_64(15, 18);
+  struct Header {
+    uptr map_beg;
+    uptr map_size;
+    uptr size;
+    uptr chunk_idx;
+  };
+
+  Header *GetHeader(uptr p) {
+    CHECK(IsAligned(p, page_size_));
+    return reinterpret_cast<Header*>(p - page_size_);
+  }
+  Header *GetHeader(const void *p) {
+    return GetHeader(reinterpret_cast<uptr>(p));
+  }
+
+  void *GetUser(Header *h) {
+    CHECK(IsAligned((uptr)h, page_size_));
+    return reinterpret_cast<void*>(reinterpret_cast<uptr>(h) + page_size_);
+  }
+
+  uptr RoundUpMapSize(uptr size) {
+    return RoundUpTo(size, page_size_) + page_size_;
+  }
+
+  uptr page_size_;
+  Header *chunks_[kMaxNumChunks];
+  uptr n_chunks_;
+  uptr min_mmap_, max_mmap_;
+  bool chunks_sorted_;
+  struct Stats {
+    uptr n_allocs, n_frees, currently_allocated, max_allocated, by_size_log[64];
+  } stats;
+  SpinMutex mutex_;
+};
+
+// This class implements a complete memory allocator by using two
+// internal allocators:
+// PrimaryAllocator is efficient, but may not allocate some sizes (alignments).
+//  When allocating 2^x bytes it should return 2^x aligned chunk.
+// PrimaryAllocator is used via a local AllocatorCache.
+// SecondaryAllocator can allocate anything, but is not efficient.
+template <class PrimaryAllocator, class AllocatorCache,
+          class SecondaryAllocator>  // NOLINT
+class CombinedAllocator {
+ public:
+  void Init() {
+    primary_.Init();
+    secondary_.Init();
+    stats_.Init();
+  }
+
+  void *Allocate(AllocatorCache *cache, uptr size, uptr alignment,
+                 bool cleared = false) {
+    // Returning 0 on malloc(0) may break a lot of code.
+    if (size == 0)
+      size = 1;
+    if (size + alignment < size)
+      return AllocatorReturnNull();
+    if (alignment > 8)
+      size = RoundUpTo(size, alignment);
+    void *res;
+    bool from_primary = primary_.CanAllocate(size, alignment);
+    if (from_primary)
+      res = cache->Allocate(&primary_, primary_.ClassID(size));
+    else
+      res = secondary_.Allocate(&stats_, size, alignment);
+    if (alignment > 8)
+      CHECK_EQ(reinterpret_cast<uptr>(res) & (alignment - 1), 0);
+    if (cleared && res && from_primary)
+      internal_bzero_aligned16(res, RoundUpTo(size, 16));
+    return res;
+  }
+
+  void Deallocate(AllocatorCache *cache, void *p) {
+    if (!p) return;
+    if (primary_.PointerIsMine(p))
+      cache->Deallocate(&primary_, primary_.GetSizeClass(p), p);
+    else
+      secondary_.Deallocate(&stats_, p);
+  }
+
+  void *Reallocate(AllocatorCache *cache, void *p, uptr new_size,
+                   uptr alignment) {
+    if (!p)
+      return Allocate(cache, new_size, alignment);
+    if (!new_size) {
+      Deallocate(cache, p);
+      return 0;
+    }
+    CHECK(PointerIsMine(p));
+    uptr old_size = GetActuallyAllocatedSize(p);
+    uptr memcpy_size = Min(new_size, old_size);
+    void *new_p = Allocate(cache, new_size, alignment);
+    if (new_p)
+      internal_memcpy(new_p, p, memcpy_size);
+    Deallocate(cache, p);
+    return new_p;
+  }
+
+  bool PointerIsMine(void *p) {
+    if (primary_.PointerIsMine(p))
+      return true;
+    return secondary_.PointerIsMine(p);
+  }
+
+  bool FromPrimary(void *p) {
+    return primary_.PointerIsMine(p);
+  }
+
+  void *GetMetaData(const void *p) {
+    if (primary_.PointerIsMine(p))
+      return primary_.GetMetaData(p);
+    return secondary_.GetMetaData(p);
+  }
+
+  void *GetBlockBegin(const void *p) {
+    if (primary_.PointerIsMine(p))
+      return primary_.GetBlockBegin(p);
+    return secondary_.GetBlockBegin(p);
+  }
+
+  // This function does the same as GetBlockBegin, but is much faster.
+  // Must be called with the allocator locked.
+  void *GetBlockBeginFastLocked(void *p) {
+    if (primary_.PointerIsMine(p))
+      return primary_.GetBlockBegin(p);
+    return secondary_.GetBlockBeginFastLocked(p);
+  }
+
+  uptr GetActuallyAllocatedSize(void *p) {
+    if (primary_.PointerIsMine(p))
+      return primary_.GetActuallyAllocatedSize(p);
+    return secondary_.GetActuallyAllocatedSize(p);
+  }
+
+  uptr TotalMemoryUsed() {
+    return primary_.TotalMemoryUsed() + secondary_.TotalMemoryUsed();
+  }
+
+  void TestOnlyUnmap() { primary_.TestOnlyUnmap(); }
+
+  void InitCache(AllocatorCache *cache) {
+    cache->Init(&stats_);
+  }
+
+  void DestroyCache(AllocatorCache *cache) {
+    cache->Destroy(&primary_, &stats_);
+  }
+
+  void SwallowCache(AllocatorCache *cache) {
+    cache->Drain(&primary_);
+  }
+
+  void GetStats(AllocatorStatCounters s) const {
+    stats_.Get(s);
+  }
+
+  void PrintStats() {
+    primary_.PrintStats();
+    secondary_.PrintStats();
+  }
+
+  // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
+  // introspection API.
+  void ForceLock() {
+    primary_.ForceLock();
+    secondary_.ForceLock();
+  }
+
+  void ForceUnlock() {
+    secondary_.ForceUnlock();
+    primary_.ForceUnlock();
+  }
+
+  // Iterate over all existing chunks.
+  // The allocator must be locked when calling this function.
+  void ForEachChunk(ForEachChunkCallback callback, void *arg) {
+    primary_.ForEachChunk(callback, arg);
+    secondary_.ForEachChunk(callback, arg);
+  }
+
+ private:
+  PrimaryAllocator primary_;
+  SecondaryAllocator secondary_;
+  AllocatorGlobalStats stats_;
+};
+
+// Returns true if calloc(size, n) should return 0 due to overflow in size*n.
+bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n);
+
+}  // namespace __sanitizer
+
+#endif  // SANITIZER_ALLOCATOR_H