diff --git a/src/heap/object-stats.cc b/src/heap/object-stats.cc
new file mode 100644
index 0000000..c1566ab
--- /dev/null
+++ b/src/heap/object-stats.cc
@@ -0,0 +1,252 @@
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/heap/object-stats.h"
+
+#include "src/counters.h"
+#include "src/heap/heap-inl.h"
+#include "src/isolate.h"
+#include "src/utils.h"
+
+namespace v8 {
+namespace internal {
+
+static base::LazyMutex object_stats_mutex = LAZY_MUTEX_INITIALIZER;
+
+
+void ObjectStats::ClearObjectStats(bool clear_last_time_stats) {
+  memset(object_counts_, 0, sizeof(object_counts_));
+  memset(object_sizes_, 0, sizeof(object_sizes_));
+  if (clear_last_time_stats) {
+    memset(object_counts_last_time_, 0, sizeof(object_counts_last_time_));
+    memset(object_sizes_last_time_, 0, sizeof(object_sizes_last_time_));
+  }
+}
+
+
+void ObjectStats::TraceObjectStat(const char* name, int count, int size,
+                                  double time) {
+  int ms_count = heap()->ms_count();
+  PrintIsolate(isolate(),
+               "heap:%p, time:%f, gc:%d, type:%s, count:%d, size:%d\n",
+               static_cast<void*>(heap()), time, ms_count, name, count, size);
+}
+
+
+void ObjectStats::TraceObjectStats() {
+  base::LockGuard<base::Mutex> lock_guard(object_stats_mutex.Pointer());
+  int index;
+  int count;
+  int size;
+  int total_size = 0;
+  double time = isolate()->time_millis_since_init();
+#define TRACE_OBJECT_COUNT(name)                     \
+  count = static_cast<int>(object_counts_[name]);    \
+  size = static_cast<int>(object_sizes_[name]) / KB; \
+  total_size += size;                                \
+  TraceObjectStat(#name, count, size, time);
+  INSTANCE_TYPE_LIST(TRACE_OBJECT_COUNT)
+#undef TRACE_OBJECT_COUNT
+#define TRACE_OBJECT_COUNT(name)                      \
+  index = FIRST_CODE_KIND_SUB_TYPE + Code::name;      \
+  count = static_cast<int>(object_counts_[index]);    \
+  size = static_cast<int>(object_sizes_[index]) / KB; \
+  TraceObjectStat("*CODE_" #name, count, size, time);
+  CODE_KIND_LIST(TRACE_OBJECT_COUNT)
+#undef TRACE_OBJECT_COUNT
+#define TRACE_OBJECT_COUNT(name)                      \
+  index = FIRST_FIXED_ARRAY_SUB_TYPE + name;          \
+  count = static_cast<int>(object_counts_[index]);    \
+  size = static_cast<int>(object_sizes_[index]) / KB; \
+  TraceObjectStat("*FIXED_ARRAY_" #name, count, size, time);
+  FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(TRACE_OBJECT_COUNT)
+#undef TRACE_OBJECT_COUNT
+#define TRACE_OBJECT_COUNT(name)                                              \
+  index =                                                                     \
+      FIRST_CODE_AGE_SUB_TYPE + Code::k##name##CodeAge - Code::kFirstCodeAge; \
+  count = static_cast<int>(object_counts_[index]);                            \
+  size = static_cast<int>(object_sizes_[index]) / KB;                         \
+  TraceObjectStat("*CODE_AGE_" #name, count, size, time);
+  CODE_AGE_LIST_COMPLETE(TRACE_OBJECT_COUNT)
+#undef TRACE_OBJECT_COUNT
+}
+
+
+void ObjectStats::CheckpointObjectStats() {
+  base::LockGuard<base::Mutex> lock_guard(object_stats_mutex.Pointer());
+  Counters* counters = isolate()->counters();
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name)              \
+  counters->count_of_##name()->Increment(                \
+      static_cast<int>(object_counts_[name]));           \
+  counters->count_of_##name()->Decrement(                \
+      static_cast<int>(object_counts_last_time_[name])); \
+  counters->size_of_##name()->Increment(                 \
+      static_cast<int>(object_sizes_[name]));            \
+  counters->size_of_##name()->Decrement(                 \
+      static_cast<int>(object_sizes_last_time_[name]));
+  INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+  int index;
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name)               \
+  index = FIRST_CODE_KIND_SUB_TYPE + Code::name;          \
+  counters->count_of_CODE_TYPE_##name()->Increment(       \
+      static_cast<int>(object_counts_[index]));           \
+  counters->count_of_CODE_TYPE_##name()->Decrement(       \
+      static_cast<int>(object_counts_last_time_[index])); \
+  counters->size_of_CODE_TYPE_##name()->Increment(        \
+      static_cast<int>(object_sizes_[index]));            \
+  counters->size_of_CODE_TYPE_##name()->Decrement(        \
+      static_cast<int>(object_sizes_last_time_[index]));
+  CODE_KIND_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name)               \
+  index = FIRST_FIXED_ARRAY_SUB_TYPE + name;              \
+  counters->count_of_FIXED_ARRAY_##name()->Increment(     \
+      static_cast<int>(object_counts_[index]));           \
+  counters->count_of_FIXED_ARRAY_##name()->Decrement(     \
+      static_cast<int>(object_counts_last_time_[index])); \
+  counters->size_of_FIXED_ARRAY_##name()->Increment(      \
+      static_cast<int>(object_sizes_[index]));            \
+  counters->size_of_FIXED_ARRAY_##name()->Decrement(      \
+      static_cast<int>(object_sizes_last_time_[index]));
+  FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name)                                   \
+  index =                                                                     \
+      FIRST_CODE_AGE_SUB_TYPE + Code::k##name##CodeAge - Code::kFirstCodeAge; \
+  counters->count_of_CODE_AGE_##name()->Increment(                            \
+      static_cast<int>(object_counts_[index]));                               \
+  counters->count_of_CODE_AGE_##name()->Decrement(                            \
+      static_cast<int>(object_counts_last_time_[index]));                     \
+  counters->size_of_CODE_AGE_##name()->Increment(                             \
+      static_cast<int>(object_sizes_[index]));                                \
+  counters->size_of_CODE_AGE_##name()->Decrement(                             \
+      static_cast<int>(object_sizes_last_time_[index]));
+  CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+
+  MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
+  MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
+  ClearObjectStats();
+}
+
+
+Isolate* ObjectStats::isolate() { return heap()->isolate(); }
+
+
+void ObjectStatsVisitor::CountFixedArray(
+    FixedArrayBase* fixed_array, FixedArraySubInstanceType fast_type,
+    FixedArraySubInstanceType dictionary_type) {
+  Heap* heap = fixed_array->map()->GetHeap();
+  if (fixed_array->map() != heap->fixed_cow_array_map() &&
+      fixed_array->map() != heap->fixed_double_array_map() &&
+      fixed_array != heap->empty_fixed_array()) {
+    if (fixed_array->IsDictionary()) {
+      heap->object_stats_->RecordFixedArraySubTypeStats(dictionary_type,
+                                                        fixed_array->Size());
+    } else {
+      heap->object_stats_->RecordFixedArraySubTypeStats(fast_type,
+                                                        fixed_array->Size());
+    }
+  }
+}
+
+
+void ObjectStatsVisitor::VisitBase(VisitorId id, Map* map, HeapObject* obj) {
+  Heap* heap = map->GetHeap();
+  int object_size = obj->Size();
+  heap->object_stats_->RecordObjectStats(map->instance_type(), object_size);
+  table_.GetVisitorById(id)(map, obj);
+  if (obj->IsJSObject()) {
+    JSObject* object = JSObject::cast(obj);
+    CountFixedArray(object->elements(), DICTIONARY_ELEMENTS_SUB_TYPE,
+                    FAST_ELEMENTS_SUB_TYPE);
+    CountFixedArray(object->properties(), DICTIONARY_PROPERTIES_SUB_TYPE,
+                    FAST_PROPERTIES_SUB_TYPE);
+  }
+}
+
+
+template <ObjectStatsVisitor::VisitorId id>
+void ObjectStatsVisitor::Visit(Map* map, HeapObject* obj) {
+  VisitBase(id, map, obj);
+}
+
+
+template <>
+void ObjectStatsVisitor::Visit<ObjectStatsVisitor::kVisitMap>(Map* map,
+                                                              HeapObject* obj) {
+  Heap* heap = map->GetHeap();
+  Map* map_obj = Map::cast(obj);
+  DCHECK(map->instance_type() == MAP_TYPE);
+  DescriptorArray* array = map_obj->instance_descriptors();
+  if (map_obj->owns_descriptors() && array != heap->empty_descriptor_array()) {
+    int fixed_array_size = array->Size();
+    heap->object_stats_->RecordFixedArraySubTypeStats(DESCRIPTOR_ARRAY_SUB_TYPE,
+                                                      fixed_array_size);
+  }
+  if (map_obj->has_code_cache()) {
+    CodeCache* cache = CodeCache::cast(map_obj->code_cache());
+    heap->object_stats_->RecordFixedArraySubTypeStats(
+        MAP_CODE_CACHE_SUB_TYPE, cache->default_cache()->Size());
+    if (!cache->normal_type_cache()->IsUndefined()) {
+      heap->object_stats_->RecordFixedArraySubTypeStats(
+          MAP_CODE_CACHE_SUB_TYPE,
+          FixedArray::cast(cache->normal_type_cache())->Size());
+    }
+  }
+  VisitBase(kVisitMap, map, obj);
+}
+
+
+template <>
+void ObjectStatsVisitor::Visit<ObjectStatsVisitor::kVisitCode>(
+    Map* map, HeapObject* obj) {
+  Heap* heap = map->GetHeap();
+  int object_size = obj->Size();
+  DCHECK(map->instance_type() == CODE_TYPE);
+  Code* code_obj = Code::cast(obj);
+  heap->object_stats_->RecordCodeSubTypeStats(code_obj->kind(),
+                                              code_obj->GetAge(), object_size);
+  VisitBase(kVisitCode, map, obj);
+}
+
+
+template <>
+void ObjectStatsVisitor::Visit<ObjectStatsVisitor::kVisitSharedFunctionInfo>(
+    Map* map, HeapObject* obj) {
+  Heap* heap = map->GetHeap();
+  SharedFunctionInfo* sfi = SharedFunctionInfo::cast(obj);
+  if (sfi->scope_info() != heap->empty_fixed_array()) {
+    heap->object_stats_->RecordFixedArraySubTypeStats(
+        SCOPE_INFO_SUB_TYPE, FixedArray::cast(sfi->scope_info())->Size());
+  }
+  VisitBase(kVisitSharedFunctionInfo, map, obj);
+}
+
+
+template <>
+void ObjectStatsVisitor::Visit<ObjectStatsVisitor::kVisitFixedArray>(
+    Map* map, HeapObject* obj) {
+  Heap* heap = map->GetHeap();
+  FixedArray* fixed_array = FixedArray::cast(obj);
+  if (fixed_array == heap->string_table()) {
+    heap->object_stats_->RecordFixedArraySubTypeStats(STRING_TABLE_SUB_TYPE,
+                                                      fixed_array->Size());
+  }
+  VisitBase(kVisitFixedArray, map, obj);
+}
+
+
+void ObjectStatsVisitor::Initialize(VisitorDispatchTable<Callback>* original) {
+  // Copy the original visitor table to make call-through possible. After we
+  // preserved a copy locally, we patch the original table to call us.
+  table_.CopyFrom(original);
+#define COUNT_FUNCTION(id) original->Register(kVisit##id, Visit<kVisit##id>);
+  VISITOR_ID_LIST(COUNT_FUNCTION)
+#undef COUNT_FUNCTION
+}
+
+}  // namespace internal
+}  // namespace v8