diff --git a/src/malloc_extension.cc b/src/malloc_extension.cc
new file mode 100644
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+++ b/src/malloc_extension.cc
@@ -0,0 +1,378 @@
+// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
+// Copyright (c) 2005, Google Inc.
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+// 
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ---
+// Author: Sanjay Ghemawat <opensource@google.com>
+
+#include <config.h>
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#if defined HAVE_STDINT_H
+#include <stdint.h>
+#elif defined HAVE_INTTYPES_H
+#include <inttypes.h>
+#else
+#include <sys/types.h>
+#endif
+#include <string>
+#include "base/dynamic_annotations.h"
+#include "base/sysinfo.h"    // for FillProcSelfMaps
+#ifndef NO_HEAP_CHECK
+#include "gperftools/heap-checker.h"
+#endif
+#include "gperftools/malloc_extension.h"
+#include "gperftools/malloc_extension_c.h"
+#include "maybe_threads.h"
+#include "base/googleinit.h"
+
+using STL_NAMESPACE::string;
+using STL_NAMESPACE::vector;
+
+static void DumpAddressMap(string* result) {
+  *result += "\nMAPPED_LIBRARIES:\n";
+  // We keep doubling until we get a fit
+  const size_t old_resultlen = result->size();
+  for (int amap_size = 10240; amap_size < 10000000; amap_size *= 2) {
+    result->resize(old_resultlen + amap_size);
+    bool wrote_all = false;
+    const int bytes_written =
+        tcmalloc::FillProcSelfMaps(&((*result)[old_resultlen]), amap_size,
+                                   &wrote_all);
+    if (wrote_all) {   // we fit!
+      (*result)[old_resultlen + bytes_written] = '\0';
+      result->resize(old_resultlen + bytes_written);
+      return;
+    }
+  }
+  result->reserve(old_resultlen);   // just don't print anything
+}
+
+// Note: this routine is meant to be called before threads are spawned.
+void MallocExtension::Initialize() {
+  static bool initialize_called = false;
+
+  if (initialize_called) return;
+  initialize_called = true;
+
+#ifdef __GLIBC__
+  // GNU libc++ versions 3.3 and 3.4 obey the environment variables
+  // GLIBCPP_FORCE_NEW and GLIBCXX_FORCE_NEW respectively.  Setting
+  // one of these variables forces the STL default allocator to call
+  // new() or delete() for each allocation or deletion.  Otherwise
+  // the STL allocator tries to avoid the high cost of doing
+  // allocations by pooling memory internally.  However, tcmalloc
+  // does allocations really fast, especially for the types of small
+  // items one sees in STL, so it's better off just using us.
+  // TODO: control whether we do this via an environment variable?
+  setenv("GLIBCPP_FORCE_NEW", "1", false /* no overwrite*/);
+  setenv("GLIBCXX_FORCE_NEW", "1", false /* no overwrite*/);
+
+  // Now we need to make the setenv 'stick', which it may not do since
+  // the env is flakey before main() is called.  But luckily stl only
+  // looks at this env var the first time it tries to do an alloc, and
+  // caches what it finds.  So we just cause an stl alloc here.
+  string dummy("I need to be allocated");
+  dummy += "!";         // so the definition of dummy isn't optimized out
+#endif  /* __GLIBC__ */
+}
+
+// SysAllocator implementation
+SysAllocator::~SysAllocator() {}
+
+// Default implementation -- does nothing
+MallocExtension::~MallocExtension() { }
+bool MallocExtension::VerifyAllMemory() { return true; }
+bool MallocExtension::VerifyNewMemory(const void* p) { return true; }
+bool MallocExtension::VerifyArrayNewMemory(const void* p) { return true; }
+bool MallocExtension::VerifyMallocMemory(const void* p) { return true; }
+
+bool MallocExtension::GetNumericProperty(const char* property, size_t* value) {
+  return false;
+}
+
+bool MallocExtension::SetNumericProperty(const char* property, size_t value) {
+  return false;
+}
+
+void MallocExtension::GetStats(char* buffer, int length) {
+  assert(length > 0);
+  buffer[0] = '\0';
+}
+
+bool MallocExtension::MallocMemoryStats(int* blocks, size_t* total,
+                                       int histogram[kMallocHistogramSize]) {
+  *blocks = 0;
+  *total = 0;
+  memset(histogram, 0, sizeof(*histogram) * kMallocHistogramSize);
+  return true;
+}
+
+void** MallocExtension::ReadStackTraces(int* sample_period) {
+  return NULL;
+}
+
+void** MallocExtension::ReadHeapGrowthStackTraces() {
+  return NULL;
+}
+
+void MallocExtension::MarkThreadIdle() {
+  // Default implementation does nothing
+}
+
+void MallocExtension::MarkThreadBusy() {
+  // Default implementation does nothing
+}
+
+SysAllocator* MallocExtension::GetSystemAllocator() {
+  return NULL;
+}
+
+void MallocExtension::SetSystemAllocator(SysAllocator *a) {
+  // Default implementation does nothing
+}
+
+void MallocExtension::ReleaseToSystem(size_t num_bytes) {
+  // Default implementation does nothing
+}
+
+void MallocExtension::ReleaseFreeMemory() {
+  ReleaseToSystem(static_cast<size_t>(-1));   // SIZE_T_MAX
+}
+
+void MallocExtension::SetMemoryReleaseRate(double rate) {
+  // Default implementation does nothing
+}
+
+double MallocExtension::GetMemoryReleaseRate() {
+  return -1.0;
+}
+
+size_t MallocExtension::GetEstimatedAllocatedSize(size_t size) {
+  return size;
+}
+
+size_t MallocExtension::GetAllocatedSize(const void* p) {
+  assert(GetOwnership(p) != kNotOwned);
+  return 0;
+}
+
+MallocExtension::Ownership MallocExtension::GetOwnership(const void* p) {
+  return kUnknownOwnership;
+}
+
+void MallocExtension::GetFreeListSizes(
+    vector<MallocExtension::FreeListInfo>* v) {
+  v->clear();
+}
+
+// The current malloc extension object.
+
+static MallocExtension* current_instance;
+
+static void InitModule() {
+  if (current_instance != NULL) {
+    return;
+  }
+  current_instance = new MallocExtension;
+#ifndef NO_HEAP_CHECK
+  HeapLeakChecker::IgnoreObject(current_instance);
+#endif
+}
+
+REGISTER_MODULE_INITIALIZER(malloc_extension_init, InitModule())
+
+MallocExtension* MallocExtension::instance() {
+  InitModule();
+  return current_instance;
+}
+
+void MallocExtension::Register(MallocExtension* implementation) {
+  InitModule();
+  // When running under valgrind, our custom malloc is replaced with
+  // valgrind's one and malloc extensions will not work.  (Note:
+  // callers should be responsible for checking that they are the
+  // malloc that is really being run, before calling Register.  This
+  // is just here as an extra sanity check.)
+  if (!RunningOnValgrind()) {
+    current_instance = implementation;
+  }
+}
+
+// -----------------------------------------------------------------------
+// Heap sampling support
+// -----------------------------------------------------------------------
+
+namespace {
+
+// Accessors
+uintptr_t Count(void** entry) {
+  return reinterpret_cast<uintptr_t>(entry[0]);
+}
+uintptr_t Size(void** entry) {
+  return reinterpret_cast<uintptr_t>(entry[1]);
+}
+uintptr_t Depth(void** entry) {
+  return reinterpret_cast<uintptr_t>(entry[2]);
+}
+void* PC(void** entry, int i) {
+  return entry[3+i];
+}
+
+void PrintCountAndSize(MallocExtensionWriter* writer,
+                       uintptr_t count, uintptr_t size) {
+  char buf[100];
+  snprintf(buf, sizeof(buf),
+           "%6" PRIu64 ": %8" PRIu64 " [%6" PRIu64 ": %8" PRIu64 "] @",
+           static_cast<uint64>(count),
+           static_cast<uint64>(size),
+           static_cast<uint64>(count),
+           static_cast<uint64>(size));
+  writer->append(buf, strlen(buf));
+}
+
+void PrintHeader(MallocExtensionWriter* writer,
+                 const char* label, void** entries) {
+  // Compute the total count and total size
+  uintptr_t total_count = 0;
+  uintptr_t total_size = 0;
+  for (void** entry = entries; Count(entry) != 0; entry += 3 + Depth(entry)) {
+    total_count += Count(entry);
+    total_size += Size(entry);
+  }
+
+  const char* const kTitle = "heap profile: ";
+  writer->append(kTitle, strlen(kTitle));
+  PrintCountAndSize(writer, total_count, total_size);
+  writer->append(" ", 1);
+  writer->append(label, strlen(label));
+  writer->append("\n", 1);
+}
+
+void PrintStackEntry(MallocExtensionWriter* writer, void** entry) {
+  PrintCountAndSize(writer, Count(entry), Size(entry));
+
+  for (int i = 0; i < Depth(entry); i++) {
+    char buf[32];
+    snprintf(buf, sizeof(buf), " %p", PC(entry, i));
+    writer->append(buf, strlen(buf));
+  }
+  writer->append("\n", 1);
+}
+
+}
+
+void MallocExtension::GetHeapSample(MallocExtensionWriter* writer) {
+  int sample_period = 0;
+  void** entries = ReadStackTraces(&sample_period);
+  if (entries == NULL) {
+    const char* const kErrorMsg =
+        "This malloc implementation does not support sampling.\n"
+        "As of 2005/01/26, only tcmalloc supports sampling, and\n"
+        "you are probably running a binary that does not use\n"
+        "tcmalloc.\n";
+    writer->append(kErrorMsg, strlen(kErrorMsg));
+    return;
+  }
+
+  char label[32];
+  sprintf(label, "heap_v2/%d", sample_period);
+  PrintHeader(writer, label, entries);
+  for (void** entry = entries; Count(entry) != 0; entry += 3 + Depth(entry)) {
+    PrintStackEntry(writer, entry);
+  }
+  delete[] entries;
+
+  DumpAddressMap(writer);
+}
+
+void MallocExtension::GetHeapGrowthStacks(MallocExtensionWriter* writer) {
+  void** entries = ReadHeapGrowthStackTraces();
+  if (entries == NULL) {
+    const char* const kErrorMsg =
+        "This malloc implementation does not support "
+        "ReadHeapGrowthStackTraces().\n"
+        "As of 2005/09/27, only tcmalloc supports this, and you\n"
+        "are probably running a binary that does not use tcmalloc.\n";
+    writer->append(kErrorMsg, strlen(kErrorMsg));
+    return;
+  }
+
+  // Do not canonicalize the stack entries, so that we get a
+  // time-ordered list of stack traces, which may be useful if the
+  // client wants to focus on the latest stack traces.
+  PrintHeader(writer, "growth", entries);
+  for (void** entry = entries; Count(entry) != 0; entry += 3 + Depth(entry)) {
+    PrintStackEntry(writer, entry);
+  }
+  delete[] entries;
+
+  DumpAddressMap(writer);
+}
+
+void MallocExtension::Ranges(void* arg, RangeFunction func) {
+  // No callbacks by default
+}
+
+// These are C shims that work on the current instance.
+
+#define C_SHIM(fn, retval, paramlist, arglist)          \
+  extern "C" PERFTOOLS_DLL_DECL retval MallocExtension_##fn paramlist {    \
+    return MallocExtension::instance()->fn arglist;     \
+  }
+
+C_SHIM(VerifyAllMemory, int, (void), ());
+C_SHIM(VerifyNewMemory, int, (const void* p), (p));
+C_SHIM(VerifyArrayNewMemory, int, (const void* p), (p));
+C_SHIM(VerifyMallocMemory, int, (const void* p), (p));
+C_SHIM(MallocMemoryStats, int,
+       (int* blocks, size_t* total, int histogram[kMallocHistogramSize]),
+       (blocks, total, histogram));
+
+C_SHIM(GetStats, void,
+       (char* buffer, int buffer_length), (buffer, buffer_length));
+C_SHIM(GetNumericProperty, int,
+       (const char* property, size_t* value), (property, value));
+C_SHIM(SetNumericProperty, int,
+       (const char* property, size_t value), (property, value));
+
+C_SHIM(MarkThreadIdle, void, (void), ());
+C_SHIM(MarkThreadBusy, void, (void), ());
+C_SHIM(ReleaseFreeMemory, void, (void), ());
+C_SHIM(ReleaseToSystem, void, (size_t num_bytes), (num_bytes));
+C_SHIM(GetEstimatedAllocatedSize, size_t, (size_t size), (size));
+C_SHIM(GetAllocatedSize, size_t, (const void* p), (p));
+
+// Can't use the shim here because of the need to translate the enums.
+extern "C"
+MallocExtension_Ownership MallocExtension_GetOwnership(const void* p) {
+  return static_cast<MallocExtension_Ownership>(
+      MallocExtension::instance()->GetOwnership(p));
+}