Heap profiler: reduce heap snapshots size.

The size of a snapshot is now 65-80% of the JS heap size (tested on
GMail and Wave), previously it was >200%.

BUG=783

Review URL: http://codereview.chromium.org/3060008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5211 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8-profiler.h

@@ -194,10 +194,10 @@ class HeapGraphNode;
 class V8EXPORT HeapGraphEdge {
  public:
   enum Type {
-    CONTEXT_VARIABLE = 0,  // A variable from a function context.
-    ELEMENT = 1,           // An element of an array.
-    PROPERTY = 2,          // A named object property.
-    INTERNAL = 3           // A link that can't be accessed from JS,
+    kContextVariable = 0,  // A variable from a function context.
+    kElement = 1,          // An element of an array.
+    kProperty = 2,         // A named object property.
+    kInternal = 3          // A link that can't be accessed from JS,
                            // thus, its name isn't a real property name.
   };
 
@@ -240,12 +240,12 @@ class V8EXPORT HeapGraphPath {
 class V8EXPORT HeapGraphNode {
  public:
   enum Type {
-    INTERNAL = 0,   // Internal node, a virtual one, for housekeeping.
-    ARRAY = 1,      // An array of elements.
-    STRING = 2,     // A string.
-    OBJECT = 3,     // A JS object (except for arrays and strings).
-    CODE = 4,       // Compiled code.
-    CLOSURE = 5     // Function closure.
+    kInternal = 0,   // Internal node, a virtual one, for housekeeping.
+    kArray = 1,      // An array of elements.
+    kString = 2,     // A string.
+    kObject = 3,     // A JS object (except for arrays and strings).
+    kCode = 4,       // Compiled code.
+    kClosure = 5     // Function closure.
   };
 
   /** Returns node type (see HeapGraphNode::Type). */
@@ -268,13 +268,15 @@ class V8EXPORT HeapGraphNode {
   int GetSelfSize() const;
 
   /** Returns node's network (self + reachable nodes) size, in bytes. */
-  int GetTotalSize() const;
+  int GetReachableSize() const;
 
   /**
-   * Returns node's private size, in bytes. That is, the size of memory
-   * that will be reclaimed having this node collected.
+   * Returns node's retained size, in bytes. That is, self + sizes of
+   * the objects that are reachable only from this object. In other
+   * words, the size of memory that will be reclaimed having this node
+   * collected.
    */
-  int GetPrivateSize() const;
+  int GetRetainedSize() const;
 
   /** Returns child nodes count of the node. */
   int GetChildrenCount() const;

src/api.cc

@@ -4491,24 +4491,27 @@ const CpuProfile* CpuProfiler::StopProfiling(Handle<String> title,
 }
 
 
+static i::HeapGraphEdge* ToInternal(const HeapGraphEdge* edge) {
+  return const_cast<i::HeapGraphEdge*>(
+      reinterpret_cast<const i::HeapGraphEdge*>(edge));
+}
+
 HeapGraphEdge::Type HeapGraphEdge::GetType() const {
   IsDeadCheck("v8::HeapGraphEdge::GetType");
-  return static_cast<HeapGraphEdge::Type>(
-      reinterpret_cast<const i::HeapGraphEdge*>(this)->type());
+  return static_cast<HeapGraphEdge::Type>(ToInternal(this)->type());
 }
 
 
 Handle<Value> HeapGraphEdge::GetName() const {
   IsDeadCheck("v8::HeapGraphEdge::GetName");
-  const i::HeapGraphEdge* edge =
-      reinterpret_cast<const i::HeapGraphEdge*>(this);
+  i::HeapGraphEdge* edge = ToInternal(this);
   switch (edge->type()) {
-    case i::HeapGraphEdge::CONTEXT_VARIABLE:
-    case i::HeapGraphEdge::INTERNAL:
-    case i::HeapGraphEdge::PROPERTY:
+    case i::HeapGraphEdge::kContextVariable:
+    case i::HeapGraphEdge::kInternal:
+    case i::HeapGraphEdge::kProperty:
       return Handle<String>(ToApi<String>(i::Factory::LookupAsciiSymbol(
           edge->name())));
-    case i::HeapGraphEdge::ELEMENT:
+    case i::HeapGraphEdge::kElement:
       return Handle<Number>(ToApi<Number>(i::Factory::NewNumberFromInt(
           edge->index())));
     default: UNREACHABLE();
@@ -4519,28 +4522,32 @@ Handle<Value> HeapGraphEdge::GetName() const {
 
 const HeapGraphNode* HeapGraphEdge::GetFromNode() const {
   IsDeadCheck("v8::HeapGraphEdge::GetFromNode");
-  const i::HeapEntry* from =
-      reinterpret_cast<const i::HeapGraphEdge*>(this)->from();
+  const i::HeapEntry* from = ToInternal(this)->From();
   return reinterpret_cast<const HeapGraphNode*>(from);
 }
 
 
 const HeapGraphNode* HeapGraphEdge::GetToNode() const {
   IsDeadCheck("v8::HeapGraphEdge::GetToNode");
-  const i::HeapEntry* to =
-      reinterpret_cast<const i::HeapGraphEdge*>(this)->to();
+  const i::HeapEntry* to = ToInternal(this)->to();
   return reinterpret_cast<const HeapGraphNode*>(to);
 }
 
 
+static i::HeapGraphPath* ToInternal(const HeapGraphPath* path) {
+  return const_cast<i::HeapGraphPath*>(
+      reinterpret_cast<const i::HeapGraphPath*>(path));
+}
+
+
 int HeapGraphPath::GetEdgesCount() const {
-  return reinterpret_cast<const i::HeapGraphPath*>(this)->path()->length();
+  return ToInternal(this)->path()->length();
 }
 
 
 const HeapGraphEdge* HeapGraphPath::GetEdge(int index) const {
   return reinterpret_cast<const HeapGraphEdge*>(
-      reinterpret_cast<const i::HeapGraphPath*>(this)->path()->at(index));
+      ToInternal(this)->path()->at(index));
 }
 
 
@@ -4555,137 +4562,136 @@ const HeapGraphNode* HeapGraphPath::GetToNode() const {
 }
 
 
+static i::HeapEntry* ToInternal(const HeapGraphNode* entry) {
+  return const_cast<i::HeapEntry*>(
+      reinterpret_cast<const i::HeapEntry*>(entry));
+}
+
+
 HeapGraphNode::Type HeapGraphNode::GetType() const {
   IsDeadCheck("v8::HeapGraphNode::GetType");
-  return static_cast<HeapGraphNode::Type>(
-      reinterpret_cast<const i::HeapEntry*>(this)->type());
+  return static_cast<HeapGraphNode::Type>(ToInternal(this)->type());
 }
 
 
 Handle<String> HeapGraphNode::GetName() const {
   IsDeadCheck("v8::HeapGraphNode::GetName");
   return Handle<String>(ToApi<String>(i::Factory::LookupAsciiSymbol(
-      reinterpret_cast<const i::HeapEntry*>(this)->name())));
+      ToInternal(this)->name())));
 }
 
 
 uint64_t HeapGraphNode::GetId() const {
   IsDeadCheck("v8::HeapGraphNode::GetId");
-  return reinterpret_cast<const i::HeapEntry*>(this)->id();
+  return ToInternal(this)->id();
 }
 
 
 int HeapGraphNode::GetSelfSize() const {
   IsDeadCheck("v8::HeapGraphNode::GetSelfSize");
-  return reinterpret_cast<const i::HeapEntry*>(this)->self_size();
+  return ToInternal(this)->self_size();
 }
 
 
-int HeapGraphNode::GetTotalSize() const {
-  IsDeadCheck("v8::HeapSnapshot::GetHead");
-  return const_cast<i::HeapEntry*>(
-      reinterpret_cast<const i::HeapEntry*>(this))->TotalSize();
+int HeapGraphNode::GetReachableSize() const {
+  IsDeadCheck("v8::HeapSnapshot::GetReachableSize");
+  return ToInternal(this)->ReachableSize();
 }
 
 
-int HeapGraphNode::GetPrivateSize() const {
-  IsDeadCheck("v8::HeapSnapshot::GetPrivateSize");
-  return const_cast<i::HeapEntry*>(
-      reinterpret_cast<const i::HeapEntry*>(this))->NonSharedTotalSize();
+int HeapGraphNode::GetRetainedSize() const {
+  IsDeadCheck("v8::HeapSnapshot::GetRetainedSize");
+  return ToInternal(this)->RetainedSize();
 }
 
 
 int HeapGraphNode::GetChildrenCount() const {
   IsDeadCheck("v8::HeapSnapshot::GetChildrenCount");
-  return reinterpret_cast<const i::HeapEntry*>(this)->children()->length();
+  return ToInternal(this)->children().length();
 }
 
 
 const HeapGraphEdge* HeapGraphNode::GetChild(int index) const {
   IsDeadCheck("v8::HeapSnapshot::GetChild");
   return reinterpret_cast<const HeapGraphEdge*>(
-      reinterpret_cast<const i::HeapEntry*>(this)->children()->at(index));
+      &ToInternal(this)->children()[index]);
 }
 
 
 int HeapGraphNode::GetRetainersCount() const {
   IsDeadCheck("v8::HeapSnapshot::GetRetainersCount");
-  return reinterpret_cast<const i::HeapEntry*>(this)->retainers()->length();
+  return ToInternal(this)->retainers().length();
 }
 
 
 const HeapGraphEdge* HeapGraphNode::GetRetainer(int index) const {
   IsDeadCheck("v8::HeapSnapshot::GetRetainer");
   return reinterpret_cast<const HeapGraphEdge*>(
-      reinterpret_cast<const i::HeapEntry*>(this)->retainers()->at(index));
+      ToInternal(this)->retainers()[index]);
 }
 
 
 int HeapGraphNode::GetRetainingPathsCount() const {
   IsDeadCheck("v8::HeapSnapshot::GetRetainingPathsCount");
-  return const_cast<i::HeapEntry*>(
-      reinterpret_cast<const i::HeapEntry*>(
-          this))->GetRetainingPaths()->length();
+  return ToInternal(this)->GetRetainingPaths()->length();
 }
 
 
 const HeapGraphPath* HeapGraphNode::GetRetainingPath(int index) const {
   IsDeadCheck("v8::HeapSnapshot::GetRetainingPath");
   return reinterpret_cast<const HeapGraphPath*>(
-      const_cast<i::HeapEntry*>(
-          reinterpret_cast<const i::HeapEntry*>(
-              this))->GetRetainingPaths()->at(index));
+      ToInternal(this)->GetRetainingPaths()->at(index));
 }
 
 
 const HeapGraphNode* HeapSnapshotsDiff::GetAdditionsRoot() const {
   IsDeadCheck("v8::HeapSnapshotsDiff::GetAdditionsRoot");
-  const i::HeapSnapshotsDiff* diff =
-      reinterpret_cast<const i::HeapSnapshotsDiff*>(this);
+  i::HeapSnapshotsDiff* diff =
+      const_cast<i::HeapSnapshotsDiff*>(
+          reinterpret_cast<const i::HeapSnapshotsDiff*>(this));
   return reinterpret_cast<const HeapGraphNode*>(diff->additions_root());
 }
 
 
 const HeapGraphNode* HeapSnapshotsDiff::GetDeletionsRoot() const {
   IsDeadCheck("v8::HeapSnapshotsDiff::GetDeletionsRoot");
-  const i::HeapSnapshotsDiff* diff =
-      reinterpret_cast<const i::HeapSnapshotsDiff*>(this);
+  i::HeapSnapshotsDiff* diff =
+      const_cast<i::HeapSnapshotsDiff*>(
+          reinterpret_cast<const i::HeapSnapshotsDiff*>(this));
   return reinterpret_cast<const HeapGraphNode*>(diff->deletions_root());
 }
 
 
+static i::HeapSnapshot* ToInternal(const HeapSnapshot* snapshot) {
+  return const_cast<i::HeapSnapshot*>(
+      reinterpret_cast<const i::HeapSnapshot*>(snapshot));
+}
+
+
 unsigned HeapSnapshot::GetUid() const {
   IsDeadCheck("v8::HeapSnapshot::GetUid");
-  return reinterpret_cast<const i::HeapSnapshot*>(this)->uid();
+  return ToInternal(this)->uid();
 }
 
 
 Handle<String> HeapSnapshot::GetTitle() const {
   IsDeadCheck("v8::HeapSnapshot::GetTitle");
-  const i::HeapSnapshot* snapshot =
-      reinterpret_cast<const i::HeapSnapshot*>(this);
   return Handle<String>(ToApi<String>(i::Factory::LookupAsciiSymbol(
-      snapshot->title())));
+      ToInternal(this)->title())));
 }
 
 
 const HeapGraphNode* HeapSnapshot::GetRoot() const {
   IsDeadCheck("v8::HeapSnapshot::GetHead");
-  const i::HeapSnapshot* snapshot =
-      reinterpret_cast<const i::HeapSnapshot*>(this);
-  return reinterpret_cast<const HeapGraphNode*>(snapshot->const_root());
+  return reinterpret_cast<const HeapGraphNode*>(ToInternal(this)->root());
 }
 
 
 const HeapSnapshotsDiff* HeapSnapshot::CompareWith(
     const HeapSnapshot* snapshot) const {
   IsDeadCheck("v8::HeapSnapshot::CompareWith");
-  i::HeapSnapshot* snapshot1 = const_cast<i::HeapSnapshot*>(
-      reinterpret_cast<const i::HeapSnapshot*>(this));
-  i::HeapSnapshot* snapshot2 = const_cast<i::HeapSnapshot*>(
-      reinterpret_cast<const i::HeapSnapshot*>(snapshot));
   return reinterpret_cast<const HeapSnapshotsDiff*>(
-      snapshot1->CompareWith(snapshot2));
+      ToInternal(this)->CompareWith(ToInternal(snapshot)));
 }
 
 

src/list-inl.h

@@ -126,6 +126,13 @@ void List<T, P>::Iterate(void (*callback)(T* x)) {
 }
 
 
+template<typename T, class P>
+template<class Visitor>
+void List<T, P>::Iterate(Visitor* visitor) {
+  for (int i = 0; i < length_; i++) visitor->Apply(&data_[i]);
+}
+
+
 template<typename T, class P>
 bool List<T, P>::Contains(const T& elm) {
   for (int i = 0; i < length_; i++) {

src/list.h

@@ -117,6 +117,8 @@ class List {
 
   // Iterate through all list entries, starting at index 0.
   void Iterate(void (*callback)(T* x));
+  template<class Visitor>
+  void Iterate(Visitor* visitor);
 
   // Sort all list entries (using QuickSort)
   void Sort(int (*cmp)(const T* x, const T* y));

src/profile-generator-inl.h

@@ -130,17 +130,6 @@ CodeEntry* ProfileGenerator::EntryForVMState(StateTag tag) {
   }
 }
 
-
-template<class Visitor>
-void HeapEntriesMap::Apply(Visitor* visitor) {
-  for (HashMap::Entry* p = entries_.Start();
-       p != NULL;
-       p = entries_.Next(p)) {
-    if (!IsAlias(p->value))
-      visitor->Apply(reinterpret_cast<HeapEntry*>(p->value));
-  }
-}
-
 } }  // namespace v8::internal
 
 #endif  // ENABLE_LOGGING_AND_PROFILING

src/profile-generator.cc

@@ -798,83 +798,102 @@ void ProfileGenerator::RecordTickSample(const TickSample& sample) {
 }
 
 
-HeapGraphEdge::HeapGraphEdge(Type type,
-                             const char* name,
-                             HeapEntry* from,
-                             HeapEntry* to)
-    : type_(type), name_(name), from_(from), to_(to) {
-  ASSERT(type_ == CONTEXT_VARIABLE || type_ == PROPERTY || type_ == INTERNAL);
+void HeapGraphEdge::Init(
+    int child_index, Type type, const char* name, HeapEntry* to) {
+  ASSERT(type == kContextVariable || type == kProperty || type == kInternal);
+  child_index_ = child_index;
+  type_ = type;
+  name_ = name;
+  to_ = to;
 }
 
 
-HeapGraphEdge::HeapGraphEdge(int index,
-                             HeapEntry* from,
-                             HeapEntry* to)
-    : type_(ELEMENT), index_(index), from_(from), to_(to) {
+void HeapGraphEdge::Init(int child_index, int index, HeapEntry* to) {
+  child_index_ = child_index;
+  type_ = kElement;
+  index_ = index;
+  to_ = to;
 }
 
 
-static void DeleteHeapGraphEdge(HeapGraphEdge** edge_ptr) {
-  delete *edge_ptr;
+HeapEntry* HeapGraphEdge::From() {
+  return reinterpret_cast<HeapEntry*>(this - child_index_) - 1;
 }
 
 
-static void DeleteHeapGraphPath(HeapGraphPath** path_ptr) {
-  delete *path_ptr;
+void HeapEntry::Init(HeapSnapshot* snapshot,
+                     int children_count,
+                     int retainers_count) {
+  Init(snapshot, kInternal, "", 0, 0, children_count, retainers_count);
 }
 
 
-HeapEntry::~HeapEntry() {
-  children_.Iterate(DeleteHeapGraphEdge);
-  retaining_paths_.Iterate(DeleteHeapGraphPath);
+void HeapEntry::Init(HeapSnapshot* snapshot,
+                     Type type,
+                     const char* name,
+                     uint64_t id,
+                     int self_size,
+                     int children_count,
+                     int retainers_count) {
+  snapshot_ = snapshot;
+  type_ = type;
+  painted_ = kUnpainted;
+  calculated_data_index_ = kNoCalculatedData;
+  name_ = name;
+  id_ = id;
+  self_size_ = self_size;
+  children_count_ = children_count;
+  retainers_count_ = retainers_count;
 }
 
 
-void HeapEntry::AddEdge(HeapGraphEdge* edge) {
-  children_.Add(edge);
-  edge->to()->retainers_.Add(edge);
+void HeapEntry::SetNamedReference(HeapGraphEdge::Type type,
+                                  int child_index,
+                                  const char* name,
+                                  HeapEntry* entry,
+                                  int retainer_index) {
+  children_arr()[child_index].Init(child_index, type, name, entry);
+  entry->retainers_arr()[retainer_index] = children_arr() + child_index;
 }
 
 
-void HeapEntry::SetClosureReference(const char* name, HeapEntry* entry) {
-  AddEdge(
-      new HeapGraphEdge(HeapGraphEdge::CONTEXT_VARIABLE, name, this, entry));
+void HeapEntry::SetElementReference(
+    int child_index, int index, HeapEntry* entry, int retainer_index) {
+  children_arr()[child_index].Init(child_index, index, entry);
+  entry->retainers_arr()[retainer_index] = children_arr() + child_index;
 }
 
 
-void HeapEntry::SetElementReference(int index, HeapEntry* entry) {
-  AddEdge(new HeapGraphEdge(index, this, entry));
+void HeapEntry::SetUnidirElementReference(
+    int child_index, int index, HeapEntry* entry) {
+  children_arr()[child_index].Init(child_index, index, entry);
 }
 
 
-void HeapEntry::SetInternalReference(const char* name, HeapEntry* entry) {
-  AddEdge(new HeapGraphEdge(HeapGraphEdge::INTERNAL, name, this, entry));
-}
-
-
-void HeapEntry::SetPropertyReference(const char* name, HeapEntry* entry) {
-  AddEdge(new HeapGraphEdge(HeapGraphEdge::PROPERTY, name, this, entry));
-}
-
-
-void HeapEntry::SetAutoIndexReference(HeapEntry* entry) {
-  SetElementReference(next_auto_index_++, entry);
-}
-
-
-void HeapEntry::SetUnidirAutoIndexReference(HeapEntry* entry) {
-  children_.Add(new HeapGraphEdge(next_auto_index_++, this, entry));
+int HeapEntry::ReachableSize() {
+  if (calculated_data_index_ == kNoCalculatedData) {
+    calculated_data_index_ = snapshot_->AddCalculatedData();
+  }
+  return snapshot_->GetCalculatedData(
+      calculated_data_index_).ReachableSize(this);
 }
 
 
-int HeapEntry::TotalSize() {
-  return total_size_ != kUnknownSize ? total_size_ : CalculateTotalSize();
+int HeapEntry::RetainedSize() {
+  if (calculated_data_index_ == kNoCalculatedData) {
+    calculated_data_index_ = snapshot_->AddCalculatedData();
+  }
+  return snapshot_->GetCalculatedData(
+      calculated_data_index_).RetainedSize(this);
 }
 
 
-int HeapEntry::NonSharedTotalSize() {
-  return non_shared_total_size_ != kUnknownSize ?
-      non_shared_total_size_ : CalculateNonSharedTotalSize();
+List<HeapGraphPath*>* HeapEntry::GetRetainingPaths() {
+  if (calculated_data_index_ == kNoCalculatedData) {
+    calculated_data_index_ = snapshot_->AddCalculatedData();
+  }
+  return snapshot_->GetCalculatedData(
+      calculated_data_index_).GetRetainingPaths(this);
 }
 
 
@@ -882,16 +901,16 @@ template<class Visitor>
 void HeapEntry::ApplyAndPaintAllReachable(Visitor* visitor) {
   List<HeapEntry*> list(10);
   list.Add(this);
-  this->PaintReachable();
+  this->paint_reachable();
   visitor->Apply(this);
   while (!list.is_empty()) {
     HeapEntry* entry = list.RemoveLast();
-    const int children_count = entry->children_.length();
-    for (int i = 0; i < children_count; ++i) {
-      HeapEntry* child = entry->children_[i]->to();
+    Vector<HeapGraphEdge> children = entry->children();
+    for (int i = 0; i < children.length(); ++i) {
+      HeapEntry* child = children[i].to();
       if (!child->painted_reachable()) {
         list.Add(child);
-        child->PaintReachable();
+        child->paint_reachable();
         visitor->Apply(child);
       }
     }
@@ -910,78 +929,158 @@ void HeapEntry::PaintAllReachable() {
 }
 
 
-class TotalSizeCalculator {
- public:
-  TotalSizeCalculator()
-      : total_size_(0) {
+void HeapEntry::Print(int max_depth, int indent) {
+  OS::Print("%6d %6d %6d [%ld] ",
+            self_size(), ReachableSize(), RetainedSize(), id_);
+  if (type() != kString) {
+    OS::Print("%s %.40s\n", TypeAsString(), name_);
+  } else {
+    OS::Print("\"");
+    const char* c = name_;
+    while (*c && (c - name_) <= 40) {
+      if (*c != '\n')
+        OS::Print("%c", *c);
+      else
+        OS::Print("\\n");
+      ++c;
+    }
+    OS::Print("\"\n");
   }
+  if (--max_depth == 0) return;
+  Vector<HeapGraphEdge> ch = children();
+  for (int i = 0; i < ch.length(); ++i) {
+    HeapGraphEdge& edge = ch[i];
+    switch (edge.type()) {
+      case HeapGraphEdge::kContextVariable:
+        OS::Print("  %*c #%s: ", indent, ' ', edge.name());
+        break;
+      case HeapGraphEdge::kElement:
+        OS::Print("  %*c %d: ", indent, ' ', edge.index());
+        break;
+      case HeapGraphEdge::kInternal:
+        OS::Print("  %*c $%s: ", indent, ' ', edge.name());
+        break;
+      case HeapGraphEdge::kProperty:
+        OS::Print("  %*c %s: ", indent, ' ', edge.name());
+        break;
+      default:
+        OS::Print("!!! unknown edge type: %d ", edge.type());
+    }
+    edge.to()->Print(max_depth, indent + 2);
+  }
+}
 
-  int total_size() const { return total_size_; }
 
-  void Apply(HeapEntry* entry) {
-    total_size_ += entry->self_size();
+const char* HeapEntry::TypeAsString() {
+  switch (type()) {
+    case kInternal: return "/internal/";
+    case kObject: return "/object/";
+    case kClosure: return "/closure/";
+    case kString: return "/string/";
+    case kCode: return "/code/";
+    case kArray: return "/array/";
+    default: return "???";
   }
+}
 
- private:
-  int total_size_;
-};
 
-int HeapEntry::CalculateTotalSize() {
-  snapshot_->ClearPaint();
-  TotalSizeCalculator calc;
-  ApplyAndPaintAllReachable(&calc);
-  total_size_ = calc.total_size();
-  return total_size_;
+int HeapEntry::EntriesSize(int entries_count,
+                           int children_count,
+                           int retainers_count) {
+  return sizeof(HeapEntry) * entries_count         // NOLINT
+      + sizeof(HeapGraphEdge) * children_count     // NOLINT
+      + sizeof(HeapGraphEdge*) * retainers_count;  // NOLINT
 }
 
 
-class NonSharedSizeCalculator {
+static void DeleteHeapGraphPath(HeapGraphPath** path_ptr) {
+  delete *path_ptr;
+}
+
+void HeapEntryCalculatedData::Dispose() {
+  if (retaining_paths_ != NULL) retaining_paths_->Iterate(DeleteHeapGraphPath);
+  delete retaining_paths_;
+}
+
+
+int HeapEntryCalculatedData::ReachableSize(HeapEntry* entry) {
+  if (reachable_size_ == kUnknownSize) CalculateSizes(entry);
+  return reachable_size_;
+}
+
+
+int HeapEntryCalculatedData::RetainedSize(HeapEntry* entry) {
+  if (retained_size_ == kUnknownSize) CalculateSizes(entry);
+  return retained_size_;
+}
+
+
+class ReachableSizeCalculator {
  public:
-  NonSharedSizeCalculator()
-      : non_shared_total_size_(0) {
+  ReachableSizeCalculator()
+      : reachable_size_(0) {
   }
 
-  int non_shared_total_size() const { return non_shared_total_size_; }
+  int reachable_size() const { return reachable_size_; }
 
   void Apply(HeapEntry* entry) {
-    if (entry->painted_reachable()) {
-      non_shared_total_size_ += entry->self_size();
+    reachable_size_ += entry->self_size();
+  }
+
+ private:
+  int reachable_size_;
+};
+
+class RetainedSizeCalculator {
+ public:
+  RetainedSizeCalculator()
+      : retained_size_(0) {
+  }
+
+  int reained_size() const { return retained_size_; }
+
+  void Apply(HeapEntry** entry_ptr) {
+    if ((*entry_ptr)->painted_reachable()) {
+      retained_size_ += (*entry_ptr)->self_size();
     }
   }
 
  private:
-  int non_shared_total_size_;
+  int retained_size_;
 };
 
-int HeapEntry::CalculateNonSharedTotalSize() {
-  // To calculate non-shared total size, first we paint all reachable
-  // nodes in one color, then we paint all nodes reachable from other
-  // nodes with a different color. Then we consider only nodes painted
-  // with the first color for calculating the total size.
-  snapshot_->ClearPaint();
-  PaintAllReachable();
+void HeapEntryCalculatedData::CalculateSizes(HeapEntry* entry) {
+  // To calculate retained size, first we paint all reachable nodes in
+  // one color (and calculate reachable size as a byproduct), then we
+  // paint (or re-paint) all nodes reachable from other nodes with a
+  // different color. Then we consider only nodes painted with the
+  // first color for calculating the retained size.
+  entry->snapshot()->ClearPaint();
+  ReachableSizeCalculator rch_size_calc;
+  entry->ApplyAndPaintAllReachable(&rch_size_calc);
+  reachable_size_ = rch_size_calc.reachable_size();
 
   List<HeapEntry*> list(10);
-  if (this != snapshot_->root()) {
-    list.Add(snapshot_->root());
-    snapshot_->root()->PaintReachableFromOthers();
+  HeapEntry* root = entry->snapshot()->root();
+  if (entry != root) {
+    list.Add(root);
+    root->paint_reachable_from_others();
   }
   while (!list.is_empty()) {
-    HeapEntry* entry = list.RemoveLast();
-    const int children_count = entry->children_.length();
-    for (int i = 0; i < children_count; ++i) {
-      HeapEntry* child = entry->children_[i]->to();
-      if (child != this && child->not_painted_reachable_from_others()) {
+    HeapEntry* curr = list.RemoveLast();
+    Vector<HeapGraphEdge> children = curr->children();
+    for (int i = 0; i < children.length(); ++i) {
+      HeapEntry* child = children[i].to();
+      if (child != entry && child->not_painted_reachable_from_others()) {
         list.Add(child);
-        child->PaintReachableFromOthers();
+        child->paint_reachable_from_others();
       }
     }
   }
 
-  NonSharedSizeCalculator calculator;
-  snapshot_->IterateEntries(&calculator);
-  non_shared_total_size_ = calculator.non_shared_total_size();
-  return non_shared_total_size_;
+  RetainedSizeCalculator ret_size_calc;
+  entry->snapshot()->IterateEntries(&ret_size_calc);
+  retained_size_ = ret_size_calc.reained_size();
 }
 
 
@@ -1019,124 +1118,33 @@ class CachedHeapGraphPath {
 };
 
 
-const List<HeapGraphPath*>* HeapEntry::GetRetainingPaths() {
-  if (retaining_paths_.length() == 0 && retainers_.length() != 0) {
+List<HeapGraphPath*>* HeapEntryCalculatedData::GetRetainingPaths(
+    HeapEntry* entry) {
+  if (retaining_paths_ == NULL) retaining_paths_ = new List<HeapGraphPath*>(4);
+  if (retaining_paths_->length() == 0 && entry->retainers().length() != 0) {
     CachedHeapGraphPath path;
-    FindRetainingPaths(this, &path);
+    FindRetainingPaths(entry, &path);
   }
-  return &retaining_paths_;
+  return retaining_paths_;
 }
 
 
-void HeapEntry::FindRetainingPaths(HeapEntry* node,
-                                   CachedHeapGraphPath* prev_path) {
-  for (int i = 0; i < node->retainers_.length(); ++i) {
-    HeapGraphEdge* ret_edge = node->retainers_[i];
-    if (prev_path->ContainsNode(ret_edge->from())) continue;
-    if (ret_edge->from() != snapshot_->root()) {
+void HeapEntryCalculatedData::FindRetainingPaths(
+    HeapEntry* entry,
+    CachedHeapGraphPath* prev_path) {
+  Vector<HeapGraphEdge*> retainers = entry->retainers();
+  for (int i = 0; i < retainers.length(); ++i) {
+    HeapGraphEdge* ret_edge = retainers[i];
+    if (prev_path->ContainsNode(ret_edge->From())) continue;
+    if (ret_edge->From() != entry->snapshot()->root()) {
       CachedHeapGraphPath path(*prev_path);
       path.Add(ret_edge);
-      FindRetainingPaths(ret_edge->from(), &path);
+      FindRetainingPaths(ret_edge->From(), &path);
     } else {
       HeapGraphPath* ret_path = new HeapGraphPath(*prev_path->path());
       ret_path->Set(0, ret_edge);
-      retaining_paths_.Add(ret_path);
-    }
-  }
-}
-
-
-static void RemoveEdge(List<HeapGraphEdge*>* list, HeapGraphEdge* edge) {
-  for (int i = 0; i < list->length(); ) {
-    if (list->at(i) == edge) {
-      list->Remove(i);
-      return;
-    } else {
-      ++i;
-    }
-  }
-  UNREACHABLE();
-}
-
-
-void HeapEntry::RemoveChild(HeapGraphEdge* edge) {
-  RemoveEdge(&children_, edge);
-  delete edge;
-}
-
-
-void HeapEntry::RemoveRetainer(HeapGraphEdge* edge) {
-  RemoveEdge(&retainers_, edge);
-}
-
-
-void HeapEntry::CutEdges() {
-  for (int i = 0; i < children_.length(); ++i) {
-    HeapGraphEdge* edge = children_[i];
-    edge->to()->RemoveRetainer(edge);
-  }
-  children_.Iterate(DeleteHeapGraphEdge);
-  children_.Clear();
-
-  for (int i = 0; i < retainers_.length(); ++i) {
-    HeapGraphEdge* edge = retainers_[i];
-    edge->from()->RemoveChild(edge);
-  }
-  retainers_.Clear();
-}
-
-
-void HeapEntry::Print(int max_depth, int indent) {
-  OS::Print("%6d %6d %6d [%ld] ",
-            self_size_, TotalSize(), NonSharedTotalSize(), id_);
-  if (type_ != STRING) {
-    OS::Print("%s %.40s\n", TypeAsString(), name_);
-  } else {
-    OS::Print("\"");
-    const char* c = name_;
-    while (*c && (c - name_) <= 40) {
-      if (*c != '\n')
-        OS::Print("%c", *c);
-      else
-        OS::Print("\\n");
-      ++c;
+      retaining_paths_->Add(ret_path);
     }
-    OS::Print("\"\n");
-  }
-  if (--max_depth == 0) return;
-  const int children_count = children_.length();
-  for (int i = 0; i < children_count; ++i) {
-    HeapGraphEdge* edge = children_[i];
-    switch (edge->type()) {
-      case HeapGraphEdge::CONTEXT_VARIABLE:
-        OS::Print("  %*c #%s: ", indent, ' ', edge->name());
-        break;
-      case HeapGraphEdge::ELEMENT:
-        OS::Print("  %*c %d: ", indent, ' ', edge->index());
-        break;
-      case HeapGraphEdge::INTERNAL:
-        OS::Print("  %*c $%s: ", indent, ' ', edge->name());
-        break;
-      case HeapGraphEdge::PROPERTY:
-        OS::Print("  %*c %s: ", indent, ' ', edge->name());
-        break;
-      default:
-        OS::Print("!!! unknown edge type: %d ", edge->type());
-    }
-    edge->to()->Print(max_depth, indent + 2);
-  }
-}
-
-
-const char* HeapEntry::TypeAsString() {
-  switch (type_) {
-    case INTERNAL: return "/internal/";
-    case OBJECT: return "/object/";
-    case CLOSURE: return "/closure/";
-    case STRING: return "/string/";
-    case CODE: return "/code/";
-    case ARRAY: return "/array/";
-    default: return "???";
   }
 }
 
@@ -1151,21 +1159,21 @@ HeapGraphPath::HeapGraphPath(const List<HeapGraphEdge*>& path)
 
 
 void HeapGraphPath::Print() {
-  path_[0]->from()->Print(1, 0);
+  path_[0]->From()->Print(1, 0);
   for (int i = 0; i < path_.length(); ++i) {
     OS::Print(" -> ");
     HeapGraphEdge* edge = path_[i];
     switch (edge->type()) {
-      case HeapGraphEdge::CONTEXT_VARIABLE:
+      case HeapGraphEdge::kContextVariable:
         OS::Print("[#%s] ", edge->name());
         break;
-      case HeapGraphEdge::ELEMENT:
+      case HeapGraphEdge::kElement:
         OS::Print("[%d] ", edge->index());
         break;
-      case HeapGraphEdge::INTERNAL:
+      case HeapGraphEdge::kInternal:
         OS::Print("[$%s] ", edge->name());
         break;
-      case HeapGraphEdge::PROPERTY:
+      case HeapGraphEdge::kProperty:
         OS::Print("[%s] ", edge->name());
         break;
       default:
@@ -1177,76 +1185,8 @@ void HeapGraphPath::Print() {
 }
 
 
-class IndexedReferencesExtractor : public ObjectVisitor {
- public:
-  IndexedReferencesExtractor(HeapSnapshot* snapshot, HeapEntry* parent)
-      : snapshot_(snapshot),
-        parent_(parent) {
-  }
-
-  void VisitPointer(Object** o) {
-    if (!(*o)->IsHeapObject()) return;
-    HeapEntry* entry = snapshot_->GetEntry(HeapObject::cast(*o));
-    if (entry != NULL) {
-      parent_->SetAutoIndexReference(entry);
-    }
-  }
-
-  void VisitPointers(Object** start, Object** end) {
-    for (Object** p = start; p < end; p++) VisitPointer(p);
-  }
-
- private:
-  HeapSnapshot* snapshot_;
-  HeapEntry* parent_;
-};
-
-
-HeapEntriesMap::HeapEntriesMap()
-    : entries_(HeapObjectsMatch) {
-}
-
-
-HeapEntriesMap::~HeapEntriesMap() {
-  for (HashMap::Entry* p = entries_.Start();
-       p != NULL;
-       p = entries_.Next(p)) {
-    if (!IsAlias(p->value)) delete reinterpret_cast<HeapEntry*>(p->value);
-  }
-}
-
-
-void HeapEntriesMap::Alias(HeapObject* object, HeapEntry* entry) {
-  HashMap::Entry* cache_entry = entries_.Lookup(object, Hash(object), true);
-  if (cache_entry->value == NULL)
-    cache_entry->value = reinterpret_cast<void*>(
-        reinterpret_cast<intptr_t>(entry) | kAliasTag);
-}
-
-
-void HeapEntriesMap::Apply(void (HeapEntry::*Func)(void)) {
-  for (HashMap::Entry* p = entries_.Start();
-       p != NULL;
-       p = entries_.Next(p)) {
-    if (!IsAlias(p->value)) (reinterpret_cast<HeapEntry*>(p->value)->*Func)();
-  }
-}
-
-
-HeapEntry* HeapEntriesMap::Map(HeapObject* object) {
-  HashMap::Entry* cache_entry = entries_.Lookup(object, Hash(object), false);
-  return cache_entry != NULL ?
-      reinterpret_cast<HeapEntry*>(
-          reinterpret_cast<intptr_t>(cache_entry->value) & (~kAliasTag)) : NULL;
-}
-
-
-void HeapEntriesMap::Pair(HeapObject* object, HeapEntry* entry) {
-  HashMap::Entry* cache_entry = entries_.Lookup(object, Hash(object), true);
-  ASSERT(cache_entry->value == NULL);
-  cache_entry->value = entry;
-}
-
+HeapObject *const HeapSnapshot::kInternalRootObject =
+    reinterpret_cast<HeapObject*>(1);
 
 HeapSnapshot::HeapSnapshot(HeapSnapshotsCollection* collection,
                            const char* title,
@@ -1254,176 +1194,151 @@ HeapSnapshot::HeapSnapshot(HeapSnapshotsCollection* collection,
     : collection_(collection),
       title_(title),
       uid_(uid),
-      root_(this),
-      sorted_entries_(NULL) {
+      root_entry_index_(-1),
+      raw_entries_(NULL),
+      entries_sorted_(false) {
 }
 
 
-HeapSnapshot::~HeapSnapshot() {
-  delete sorted_entries_;
+static void DisposeCalculatedData(HeapEntryCalculatedData* cdata) {
+  cdata->Dispose();
 }
 
-
-void HeapSnapshot::ClearPaint() {
-  root_.ClearPaint();
-  entries_.Apply(&HeapEntry::ClearPaint);
+HeapSnapshot::~HeapSnapshot() {
+  DeleteArray(raw_entries_);
+  calculated_data_.Iterate(DisposeCalculatedData);
 }
 
 
-HeapEntry* HeapSnapshot::GetEntry(Object* obj) {
-  if (!obj->IsHeapObject()) return NULL;
-  HeapObject* object = HeapObject::cast(obj);
+void HeapSnapshot::AllocateEntries(int entries_count,
+                                   int children_count,
+                                   int retainers_count) {
+  ASSERT(raw_entries_ == NULL);
+  raw_entries_ = NewArray<char>(
+      HeapEntry::EntriesSize(entries_count, children_count, retainers_count));
+}
 
-  {
-    HeapEntry* existing = FindEntry(object);
-    if (existing != NULL) return existing;
-  }
 
-  // Add new entry.
-  if (object->IsJSFunction()) {
+HeapEntry* HeapSnapshot::AddEntry(HeapObject* object,
+                                  int children_count,
+                                  int retainers_count) {
+  if (object == kInternalRootObject) {
+    ASSERT(root_entry_index_ == -1);
+    root_entry_index_ = entries_.length();
+    HeapEntry* entry = GetNextEntryToInit();
+    entry->Init(this, children_count, retainers_count);
+    return entry;
+  } else if (object->IsJSFunction()) {
     JSFunction* func = JSFunction::cast(object);
     SharedFunctionInfo* shared = func->shared();
     String* name = String::cast(shared->name())->length() > 0 ?
         String::cast(shared->name()) : shared->inferred_name();
-    return AddEntry(object, HeapEntry::CLOSURE, collection_->GetName(name));
+    return AddEntry(object,
+                    HeapEntry::kClosure,
+                    collection_->GetName(name),
+                    children_count,
+                    retainers_count);
   } else if (object->IsJSObject()) {
     return AddEntry(object,
-                    HeapEntry::OBJECT,
+                    HeapEntry::kObject,
                     collection_->GetName(
-                        JSObject::cast(object)->constructor_name()));
-  } else if (object->IsJSGlobalPropertyCell()) {
-    HeapEntry* value = GetEntry(JSGlobalPropertyCell::cast(object)->value());
-    // If GPC references an object that we have interest in, add the object.
-    // We don't store HeapEntries for GPCs. Instead, we make our hash map
-    // to point to object's HeapEntry by GPCs address.
-    if (value != NULL) AddEntryAlias(object, value);
-    return value;
+                        JSObject::cast(object)->constructor_name()),
+                    children_count,
+                    retainers_count);
   } else if (object->IsString()) {
     return AddEntry(object,
-                    HeapEntry::STRING,
-                    collection_->GetName(String::cast(object)));
+                    HeapEntry::kString,
+                    collection_->GetName(String::cast(object)),
+                    children_count,
+                    retainers_count);
   } else if (object->IsCode()) {
-    return AddEntry(object, HeapEntry::CODE);
+    return AddEntry(object,
+                    HeapEntry::kCode,
+                    "",
+                    children_count,
+                    retainers_count);
   } else if (object->IsSharedFunctionInfo()) {
     SharedFunctionInfo* shared = SharedFunctionInfo::cast(object);
     String* name = String::cast(shared->name())->length() > 0 ?
         String::cast(shared->name()) : shared->inferred_name();
-    return AddEntry(object, HeapEntry::CODE, collection_->GetName(name));
+    return AddEntry(object,
+                    HeapEntry::kCode,
+                    collection_->GetName(name),
+                    children_count,
+                    retainers_count);
   } else if (object->IsScript()) {
     Script* script = Script::cast(object);
     return AddEntry(object,
-                    HeapEntry::CODE,
+                    HeapEntry::kCode,
                     script->name()->IsString() ?
-                    collection_->GetName(String::cast(script->name())) : "");
+                    collection_->GetName(String::cast(script->name())) : "",
+                    children_count,
+                    retainers_count);
   } else if (object->IsFixedArray()) {
-    return AddEntry(object, HeapEntry::ARRAY);
+    return AddEntry(object,
+                    HeapEntry::kArray,
+                    "",
+                    children_count,
+                    retainers_count);
   }
   // No interest in this object.
   return NULL;
 }
 
 
-void HeapSnapshot::SetClosureReference(HeapEntry* parent,
-                                       String* reference_name,
-                                       Object* child) {
-  HeapEntry* child_entry = GetEntry(child);
-  if (child_entry != NULL) {
-    parent->SetClosureReference(
-        collection_->GetName(reference_name), child_entry);
-  }
+bool HeapSnapshot::WillAddEntry(HeapObject* object) {
+  return object == kInternalRootObject
+      || object->IsJSFunction()
+      || object->IsJSObject()
+      || object->IsString()
+      || object->IsCode()
+      || object->IsSharedFunctionInfo()
+      || object->IsScript()
+      || object->IsFixedArray();
 }
 
 
-void HeapSnapshot::SetElementReference(HeapEntry* parent,
-                                       int index,
-                                       Object* child) {
-  HeapEntry* child_entry = GetEntry(child);
-  if (child_entry != NULL) {
-    parent->SetElementReference(index, child_entry);
-  }
+static void HeapEntryClearPaint(HeapEntry** entry_ptr) {
+  (*entry_ptr)->clear_paint();
 }
 
-
-void HeapSnapshot::SetInternalReference(HeapEntry* parent,
-                                        const char* reference_name,
-                                        Object* child) {
-  HeapEntry* child_entry = GetEntry(child);
-  if (child_entry != NULL) {
-    parent->SetInternalReference(reference_name, child_entry);
-  }
+void HeapSnapshot::ClearPaint() {
+  entries_.Iterate(HeapEntryClearPaint);
 }
 
 
-void HeapSnapshot::SetPropertyReference(HeapEntry* parent,
-                                        String* reference_name,
-                                        Object* child) {
-  HeapEntry* child_entry = GetEntry(child);
-  if (child_entry != NULL) {
-    parent->SetPropertyReference(
-        collection_->GetName(reference_name), child_entry);
-  }
+int HeapSnapshot::AddCalculatedData() {
+  calculated_data_.Add(HeapEntryCalculatedData());
+  return calculated_data_.length() - 1;
 }
 
 
 HeapEntry* HeapSnapshot::AddEntry(HeapObject* object,
                                   HeapEntry::Type type,
-                                  const char* name) {
-  HeapEntry* entry = new HeapEntry(this,
-                                   type,
-                                   name,
-                                   collection_->GetObjectId(object->address()),
-                                   GetObjectSize(object),
-                                   GetObjectSecurityToken(object));
-  entries_.Pair(object, entry);
-
-  // Detect, if this is a JS global object of the current context, and
-  // add it to snapshot's roots. There can be several JS global objects
-  // in a context.
-  if (object->IsJSGlobalProxy()) {
-    int global_security_token = GetGlobalSecurityToken();
-    int object_security_token =
-        collection_->token_enumerator()->GetTokenId(
-            Context::cast(
-                JSGlobalProxy::cast(object)->context())->security_token());
-    if (object_security_token == TokenEnumerator::kNoSecurityToken
-        || object_security_token == global_security_token) {
-      HeapEntry* global_object_entry =
-          GetEntry(HeapObject::cast(object->map()->prototype()));
-      ASSERT(global_object_entry != NULL);
-      root_.SetAutoIndexReference(global_object_entry);
-    }
-  }
-
+                                  const char* name,
+                                  int children_count,
+                                  int retainers_count) {
+  HeapEntry* entry = GetNextEntryToInit();
+  entry->Init(this,
+              type,
+              name,
+              collection_->GetObjectId(object->address()),
+              GetObjectSize(object),
+              children_count,
+              retainers_count);
   return entry;
 }
 
 
-class EdgesCutter {
- public:
-  explicit EdgesCutter(int global_security_token)
-      : global_security_token_(global_security_token) {
-  }
-
-  void Apply(HeapEntry* entry) {
-    if (entry->security_token_id() != TokenEnumerator::kNoSecurityToken
-        && entry->security_token_id() != global_security_token_) {
-      entry->CutEdges();
-    }
+HeapEntry* HeapSnapshot::GetNextEntryToInit() {
+  if (entries_.length() > 0) {
+    HeapEntry* last_entry = entries_.last();
+    entries_.Add(reinterpret_cast<HeapEntry*>(
+        reinterpret_cast<char*>(last_entry) + last_entry->EntrySize()));
+  } else {
+    entries_.Add(reinterpret_cast<HeapEntry*>(raw_entries_));
   }
-
- private:
-  const int global_security_token_;
-};
-
-void HeapSnapshot::CutObjectsFromForeignSecurityContexts() {
-  EdgesCutter cutter(GetGlobalSecurityToken());
-  entries_.Apply(&cutter);
-}
-
-
-int HeapSnapshot::GetGlobalSecurityToken() {
-  return collection_->token_enumerator()->GetTokenId(
-      Top::context()->global()->global_context()->security_token());
+  return entries_.last();
 }
 
 
@@ -1433,16 +1348,6 @@ int HeapSnapshot::GetObjectSize(HeapObject* obj) {
 }
 
 
-int HeapSnapshot::GetObjectSecurityToken(HeapObject* obj) {
-  if (obj->IsGlobalContext()) {
-    return collection_->token_enumerator()->GetTokenId(
-        Context::cast(obj)->security_token());
-  } else {
-    return TokenEnumerator::kNoSecurityToken;
-  }
-}
-
-
 int HeapSnapshot::CalculateNetworkSize(JSObject* obj) {
   int size = obj->Size();
   // If 'properties' and 'elements' are non-empty (thus, non-shared),
@@ -1467,15 +1372,10 @@ int HeapSnapshot::CalculateNetworkSize(JSObject* obj) {
 }
 
 
-class EntriesCollector {
- public:
-  explicit EntriesCollector(List<HeapEntry*>* list) : list_(list) { }
-  void Apply(HeapEntry* entry) {
-    list_->Add(entry);
-  }
- private:
-  List<HeapEntry*>* list_;
-};
+HeapSnapshotsDiff* HeapSnapshot::CompareWith(HeapSnapshot* snapshot) {
+  return collection_->CompareSnapshots(this, snapshot);
+}
+
 
 template<class T>
 static int SortByIds(const T* entry1_ptr,
@@ -1485,22 +1385,16 @@ static int SortByIds(const T* entry1_ptr,
 }
 
 List<HeapEntry*>* HeapSnapshot::GetSortedEntriesList() {
-  if (sorted_entries_ != NULL) return sorted_entries_;
-  sorted_entries_ = new List<HeapEntry*>(entries_.capacity());
-  EntriesCollector collector(sorted_entries_);
-  entries_.Apply(&collector);
-  sorted_entries_->Sort(SortByIds);
-  return sorted_entries_;
-}
-
-
-HeapSnapshotsDiff* HeapSnapshot::CompareWith(HeapSnapshot* snapshot) {
-  return collection_->CompareSnapshots(this, snapshot);
+  if (!entries_sorted_) {
+    entries_.Sort(SortByIds);
+    entries_sorted_ = true;
+  }
+  return &entries_;
 }
 
 
 void HeapSnapshot::Print(int max_depth) {
-  root_.Print(max_depth, 0);
+  root()->Print(max_depth, 0);
 }
 
 
@@ -1635,53 +1529,343 @@ HeapSnapshotsDiff* HeapSnapshotsCollection::CompareSnapshots(
 }
 
 
+HeapEntriesMap::HeapEntriesMap()
+    : entries_(HeapObjectsMatch),
+      entries_count_(0),
+      total_children_count_(0),
+      total_retainers_count_(0) {
+}
+
+
+HeapEntriesMap::~HeapEntriesMap() {
+  for (HashMap::Entry* p = entries_.Start(); p != NULL; p = entries_.Next(p)) {
+    if (!IsAlias(p->value)) delete reinterpret_cast<EntryInfo*>(p->value);
+  }
+}
+
+
+void HeapEntriesMap::Alias(HeapObject* from, HeapObject* to) {
+  HashMap::Entry* from_cache_entry = entries_.Lookup(from, Hash(from), true);
+  HashMap::Entry* to_cache_entry = entries_.Lookup(to, Hash(to), false);
+  if (from_cache_entry->value == NULL) {
+    ASSERT(to_cache_entry != NULL);
+    from_cache_entry->value = MakeAlias(to_cache_entry->value);
+  }
+}
+
+
+HeapEntry* HeapEntriesMap::Map(HeapObject* object) {
+  HashMap::Entry* cache_entry = entries_.Lookup(object, Hash(object), false);
+  if (cache_entry != NULL) {
+    EntryInfo* entry_info =
+        reinterpret_cast<EntryInfo*>(Unalias(cache_entry->value));
+    return entry_info->entry;
+  } else {
+    return NULL;
+  }
+}
+
+
+void HeapEntriesMap::Pair(HeapObject* object, HeapEntry* entry) {
+  HashMap::Entry* cache_entry = entries_.Lookup(object, Hash(object), true);
+  ASSERT(cache_entry->value == NULL);
+  cache_entry->value = new EntryInfo(entry);
+  ++entries_count_;
+}
+
+
+void HeapEntriesMap::CountReference(HeapObject* from, HeapObject* to,
+                                    int* prev_children_count,
+                                    int* prev_retainers_count) {
+  HashMap::Entry* from_cache_entry = entries_.Lookup(from, Hash(from), true);
+  HashMap::Entry* to_cache_entry = entries_.Lookup(to, Hash(to), false);
+  ASSERT(from_cache_entry != NULL);
+  ASSERT(to_cache_entry != NULL);
+  EntryInfo* from_entry_info =
+      reinterpret_cast<EntryInfo*>(Unalias(from_cache_entry->value));
+  EntryInfo* to_entry_info =
+      reinterpret_cast<EntryInfo*>(Unalias(to_cache_entry->value));
+  if (prev_children_count)
+    *prev_children_count = from_entry_info->children_count;
+  if (prev_retainers_count)
+    *prev_retainers_count = to_entry_info->retainers_count;
+  ++from_entry_info->children_count;
+  ++to_entry_info->retainers_count;
+  ++total_children_count_;
+  ++total_retainers_count_;
+}
+
+
+template<class Visitor>
+void HeapEntriesMap::UpdateEntries(Visitor* visitor) {
+  for (HashMap::Entry* p = entries_.Start();
+       p != NULL;
+       p = entries_.Next(p)) {
+    if (!IsAlias(p->value)) {
+      EntryInfo* entry_info = reinterpret_cast<EntryInfo*>(p->value);
+      entry_info->entry = visitor->GetEntry(
+          reinterpret_cast<HeapObject*>(p->key),
+          entry_info->children_count,
+          entry_info->retainers_count);
+      entry_info->children_count = 0;
+      entry_info->retainers_count = 0;
+    }
+  }
+}
+
+
 HeapSnapshotGenerator::HeapSnapshotGenerator(HeapSnapshot* snapshot)
-    : snapshot_(snapshot) {
+    : snapshot_(snapshot),
+      collection_(snapshot->collection()),
+      filler_(NULL) {
 }
 
 
+HeapEntry *const
+HeapSnapshotGenerator::SnapshotFillerInterface::kHeapEntryPlaceholder =
+    reinterpret_cast<HeapEntry*>(1);
+
+class SnapshotCounter : public HeapSnapshotGenerator::SnapshotFillerInterface {
+ public:
+  explicit SnapshotCounter(HeapEntriesMap* entries)
+      : entries_(entries) { }
+  HeapEntry* AddEntry(HeapObject* obj) {
+    entries_->Pair(obj, kHeapEntryPlaceholder);
+    return kHeapEntryPlaceholder;
+  }
+  void SetElementReference(HeapObject* parent_obj,
+                           HeapEntry*,
+                           int,
+                           Object* child_obj,
+                           HeapEntry*) {
+    entries_->CountReference(parent_obj, HeapObject::cast(child_obj));
+  }
+  void SetNamedReference(HeapGraphEdge::Type,
+                         HeapObject* parent_obj,
+                         HeapEntry*,
+                         const char*,
+                         Object* child_obj,
+                         HeapEntry*) {
+    entries_->CountReference(parent_obj, HeapObject::cast(child_obj));
+  }
+  void SetRootReference(Object* child_obj, HeapEntry*) {
+    entries_->CountReference(
+        HeapSnapshot::kInternalRootObject, HeapObject::cast(child_obj));
+  }
+ private:
+  HeapEntriesMap* entries_;
+};
+
+
+class SnapshotFiller : public HeapSnapshotGenerator::SnapshotFillerInterface {
+ public:
+  explicit SnapshotFiller(HeapSnapshot* snapshot, HeapEntriesMap* entries)
+      : snapshot_(snapshot),
+        collection_(snapshot->collection()),
+        entries_(entries) { }
+  HeapEntry* AddEntry(HeapObject* obj) {
+    UNREACHABLE();
+    return NULL;
+  }
+  void SetElementReference(HeapObject* parent_obj,
+                           HeapEntry* parent_entry,
+                           int index,
+                           Object* child_obj,
+                           HeapEntry* child_entry) {
+    int child_index, retainer_index;
+    entries_->CountReference(parent_obj, HeapObject::cast(child_obj),
+                             &child_index, &retainer_index);
+    parent_entry->SetElementReference(
+        child_index, index, child_entry, retainer_index);
+  }
+  void SetNamedReference(HeapGraphEdge::Type type,
+                         HeapObject* parent_obj,
+                         HeapEntry* parent_entry,
+                         const char* reference_name,
+                         Object* child_obj,
+                         HeapEntry* child_entry) {
+    int child_index, retainer_index;
+    entries_->CountReference(parent_obj, HeapObject::cast(child_obj),
+                             &child_index, &retainer_index);
+    parent_entry->SetNamedReference(type,
+                              child_index,
+                              reference_name,
+                              child_entry,
+                              retainer_index);
+  }
+  void SetRootReference(Object* child_obj, HeapEntry* child_entry) {
+    int child_index, retainer_index;
+    entries_->CountReference(
+        HeapSnapshot::kInternalRootObject, HeapObject::cast(child_obj),
+        &child_index, &retainer_index);
+    snapshot_->root()->SetElementReference(
+        child_index, child_index + 1, child_entry, retainer_index);
+  }
+ private:
+  HeapSnapshot* snapshot_;
+  HeapSnapshotsCollection* collection_;
+  HeapEntriesMap* entries_;
+};
+
+class SnapshotAllocator {
+ public:
+  explicit SnapshotAllocator(HeapSnapshot* snapshot)
+      : snapshot_(snapshot) { }
+  HeapEntry* GetEntry(
+      HeapObject* obj, int children_count, int retainers_count) {
+    HeapEntry* entry =
+        snapshot_->AddEntry(obj, children_count, retainers_count);
+    ASSERT(entry != NULL);
+    return entry;
+  }
+ private:
+  HeapSnapshot* snapshot_;
+};
+
 void HeapSnapshotGenerator::GenerateSnapshot() {
   AssertNoAllocation no_alloc;
 
-  // Iterate heap contents.
-  HeapIterator iterator;
-  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
+  // Pass 1. Iterate heap contents to count entries and references.
+  SnapshotCounter counter(&entries_);
+  filler_ = &counter;
+  filler_->AddEntry(HeapSnapshot::kInternalRootObject);
+  HeapIterator iterator1;
+  for (HeapObject* obj = iterator1.next();
+       obj != NULL;
+       obj = iterator1.next()) {
     ExtractReferences(obj);
   }
 
-  snapshot_->CutObjectsFromForeignSecurityContexts();
+  // Allocate and fill entries in the snapshot, allocate references.
+  snapshot_->AllocateEntries(entries_.entries_count(),
+                             entries_.total_children_count(),
+                             entries_.total_retainers_count());
+  SnapshotAllocator allocator(snapshot_);
+  entries_.UpdateEntries(&allocator);
+
+  // Pass 2. Fill references.
+  SnapshotFiller filler(snapshot_, &entries_);
+  filler_ = &filler;
+  HeapIterator iterator2;
+  for (HeapObject* obj = iterator2.next();
+       obj != NULL;
+       obj = iterator2.next()) {
+    ExtractReferences(obj);
+  }
+}
+
+
+HeapEntry* HeapSnapshotGenerator::GetEntry(Object* obj) {
+  if (!obj->IsHeapObject()) return NULL;
+  HeapObject* object = HeapObject::cast(obj);
+  HeapEntry* entry = entries_.Map(object);
+
+  // A new entry.
+  if (entry == NULL) {
+    if (obj->IsJSGlobalPropertyCell()) {
+      Object* cell_target = JSGlobalPropertyCell::cast(obj)->value();
+      entry = GetEntry(cell_target);
+      // If GPC references an object that we have interest in (see
+      // HeapSnapshot::AddEntry, WillAddEntry), add the object.  We
+      // don't store HeapEntries for GPCs. Instead, we make our hash
+      // map to point to object's HeapEntry by GPCs address.
+      if (entry != NULL) {
+        entries_.Alias(object, HeapObject::cast(cell_target));
+      }
+      return entry;
+    }
+
+    if (snapshot_->WillAddEntry(object)) entry = filler_->AddEntry(object);
+  }
+
+  return entry;
+}
+
+
+int HeapSnapshotGenerator::GetGlobalSecurityToken() {
+  return collection_->token_enumerator()->GetTokenId(
+      Top::context()->global()->global_context()->security_token());
+}
+
+
+int HeapSnapshotGenerator::GetObjectSecurityToken(HeapObject* obj) {
+  if (obj->IsGlobalContext()) {
+    return collection_->token_enumerator()->GetTokenId(
+        Context::cast(obj)->security_token());
+  } else {
+    return TokenEnumerator::kNoSecurityToken;
+  }
 }
 
 
+class IndexedReferencesExtractor : public ObjectVisitor {
+ public:
+  IndexedReferencesExtractor(HeapSnapshotGenerator* generator,
+                             HeapObject* parent_obj,
+                             HeapEntry* parent_entry)
+      : generator_(generator),
+        parent_obj_(parent_obj),
+        parent_(parent_entry),
+        next_index_(1) {
+  }
+
+  void VisitPointer(Object** o) {
+    generator_->SetElementReference(parent_obj_, parent_, next_index_++, *o);
+  }
+
+  void VisitPointers(Object** start, Object** end) {
+    for (Object** p = start; p < end; p++) VisitPointer(p);
+  }
+
+ private:
+  HeapSnapshotGenerator* generator_;
+  HeapObject* parent_obj_;
+  HeapEntry* parent_;
+  int next_index_;
+};
+
+
 void HeapSnapshotGenerator::ExtractReferences(HeapObject* obj) {
-  HeapEntry* entry = snapshot_->GetEntry(obj);
-  if (entry == NULL) return;
-  if (entry->visited()) return;
+  // We need to reference JS global objects from snapshot's root.
+  // We also need to only include global objects from the current
+  // security context. And we don't want to add the global proxy,
+  // as we don't have a special type for it.
+  if (obj->IsJSGlobalProxy()) {
+    int global_security_token = GetGlobalSecurityToken();
+    JSGlobalProxy* proxy = JSGlobalProxy::cast(obj);
+    int object_security_token =
+        collection_->token_enumerator()->GetTokenId(
+            Context::cast(proxy->context())->security_token());
+    if (object_security_token == TokenEnumerator::kNoSecurityToken
+        || object_security_token == global_security_token) {
+      SetRootReference(proxy->map()->prototype());
+    }
+    return;
+  }
+
+  HeapEntry* entry = GetEntry(obj);
+  if (entry == NULL) return;  // No interest in this object.
 
   if (obj->IsJSObject()) {
     JSObject* js_obj = JSObject::cast(obj);
     ExtractClosureReferences(js_obj, entry);
     ExtractPropertyReferences(js_obj, entry);
     ExtractElementReferences(js_obj, entry);
-    snapshot_->SetPropertyReference(
-        entry, Heap::prototype_symbol(), js_obj->map()->prototype());
-  } else if (obj->IsJSGlobalPropertyCell()) {
-    JSGlobalPropertyCell* cell = JSGlobalPropertyCell::cast(obj);
-    snapshot_->SetElementReference(entry, 0, cell->value());
+    SetPropertyReference(
+        obj, entry, Heap::prototype_symbol(), js_obj->map()->prototype());
   } else if (obj->IsString()) {
     if (obj->IsConsString()) {
       ConsString* cs = ConsString::cast(obj);
-      snapshot_->SetElementReference(entry, 0, cs->first());
-      snapshot_->SetElementReference(entry, 1, cs->second());
+      SetElementReference(obj, entry, 0, cs->first());
+      SetElementReference(obj, entry, 1, cs->second());
     }
   } else if (obj->IsCode() || obj->IsSharedFunctionInfo() || obj->IsScript()) {
-    IndexedReferencesExtractor refs_extractor(snapshot_, entry);
+    IndexedReferencesExtractor refs_extractor(this, obj, entry);
     obj->Iterate(&refs_extractor);
   } else if (obj->IsFixedArray()) {
-    IndexedReferencesExtractor refs_extractor(snapshot_, entry);
+    IndexedReferencesExtractor refs_extractor(this, obj, entry);
     obj->Iterate(&refs_extractor);
   }
-  entry->MarkAsVisited();
 }
 
 
@@ -1700,10 +1884,10 @@ void HeapSnapshotGenerator::ExtractClosureReferences(JSObject* js_obj,
       String* local_name = *zone_scope_info.LocalName(i);
       int idx = serialized_scope_info->ContextSlotIndex(local_name, NULL);
       if (idx >= 0 && idx < context->length()) {
-        snapshot_->SetClosureReference(entry, local_name, context->get(idx));
+        SetClosureReference(js_obj, entry, local_name, context->get(idx));
       }
     }
-    snapshot_->SetInternalReference(entry, "code", func->shared());
+    SetInternalReference(js_obj, entry, "code", func->shared());
   }
 }
 
@@ -1716,13 +1900,13 @@ void HeapSnapshotGenerator::ExtractPropertyReferences(JSObject* js_obj,
       switch (descs->GetType(i)) {
         case FIELD: {
           int index = descs->GetFieldIndex(i);
-          snapshot_->SetPropertyReference(
-              entry, descs->GetKey(i), js_obj->FastPropertyAt(index));
+          SetPropertyReference(
+              js_obj, entry, descs->GetKey(i), js_obj->FastPropertyAt(index));
           break;
         }
         case CONSTANT_FUNCTION:
-          snapshot_->SetPropertyReference(
-              entry, descs->GetKey(i), descs->GetConstantFunction(i));
+          SetPropertyReference(
+              js_obj, entry, descs->GetKey(i), descs->GetConstantFunction(i));
           break;
         default: ;
       }
@@ -1733,8 +1917,8 @@ void HeapSnapshotGenerator::ExtractPropertyReferences(JSObject* js_obj,
     for (int i = 0; i < length; ++i) {
       Object* k = dictionary->KeyAt(i);
       if (dictionary->IsKey(k)) {
-        snapshot_->SetPropertyReference(
-            entry, String::cast(k), dictionary->ValueAt(i));
+        SetPropertyReference(
+            js_obj, entry, String::cast(k), dictionary->ValueAt(i));
       }
     }
   }
@@ -1750,7 +1934,7 @@ void HeapSnapshotGenerator::ExtractElementReferences(JSObject* js_obj,
         elements->length();
     for (int i = 0; i < length; ++i) {
       if (!elements->get(i)->IsTheHole()) {
-        snapshot_->SetElementReference(entry, i, elements->get(i));
+        SetElementReference(js_obj, entry, i, elements->get(i));
       }
     }
   } else if (js_obj->HasDictionaryElements()) {
@@ -1761,13 +1945,90 @@ void HeapSnapshotGenerator::ExtractElementReferences(JSObject* js_obj,
       if (dictionary->IsKey(k)) {
         ASSERT(k->IsNumber());
         uint32_t index = static_cast<uint32_t>(k->Number());
-        snapshot_->SetElementReference(entry, index, dictionary->ValueAt(i));
+        SetElementReference(js_obj, entry, index, dictionary->ValueAt(i));
       }
     }
   }
 }
 
 
+void HeapSnapshotGenerator::SetClosureReference(HeapObject* parent_obj,
+                                                HeapEntry* parent_entry,
+                                                String* reference_name,
+                                                Object* child_obj) {
+  HeapEntry* child_entry = GetEntry(child_obj);
+  if (child_entry != NULL) {
+    filler_->SetNamedReference(HeapGraphEdge::kContextVariable,
+                               parent_obj,
+                               parent_entry,
+                               collection_->GetName(reference_name),
+                               child_obj,
+                               child_entry);
+  }
+}
+
+
+void HeapSnapshotGenerator::SetElementReference(HeapObject* parent_obj,
+                                                HeapEntry* parent_entry,
+                                                int index,
+                                                Object* child_obj) {
+  HeapEntry* child_entry = GetEntry(child_obj);
+  if (child_entry != NULL) {
+    filler_->SetElementReference(
+        parent_obj, parent_entry, index, child_obj, child_entry);
+  }
+}
+
+
+void HeapSnapshotGenerator::SetInternalReference(HeapObject* parent_obj,
+                                                 HeapEntry* parent_entry,
+                                                 const char* reference_name,
+                                                 Object* child_obj) {
+  HeapEntry* child_entry = GetEntry(child_obj);
+  if (child_entry != NULL) {
+    filler_->SetNamedReference(HeapGraphEdge::kInternal,
+                               parent_obj,
+                               parent_entry,
+                               reference_name,
+                               child_obj,
+                               child_entry);
+  }
+}
+
+
+void HeapSnapshotGenerator::SetPropertyReference(HeapObject* parent_obj,
+                                                 HeapEntry* parent_entry,
+                                                 String* reference_name,
+                                                 Object* child_obj) {
+  HeapEntry* child_entry = GetEntry(child_obj);
+  if (child_entry != NULL) {
+    filler_->SetNamedReference(HeapGraphEdge::kProperty,
+                               parent_obj,
+                               parent_entry,
+                               collection_->GetName(reference_name),
+                               child_obj,
+                               child_entry);
+  }
+}
+
+
+void HeapSnapshotGenerator::SetRootReference(Object* child_obj) {
+  HeapEntry* child_entry = GetEntry(child_obj);
+  ASSERT(child_entry != NULL);
+  filler_->SetRootReference(child_obj, child_entry);
+}
+
+
+void HeapSnapshotsDiff::CreateRoots(int additions_count, int deletions_count) {
+  raw_additions_root_ =
+      NewArray<char>(HeapEntry::EntriesSize(1, additions_count, 0));
+  additions_root()->Init(snapshot2_, additions_count, 0);
+  raw_deletions_root_ =
+      NewArray<char>(HeapEntry::EntriesSize(1, deletions_count, 0));
+  deletions_root()->Init(snapshot1_, deletions_count, 0);
+}
+
+
 static void DeleteHeapSnapshotsDiff(HeapSnapshotsDiff** diff_ptr) {
   delete *diff_ptr;
 }
@@ -1779,8 +2040,6 @@ HeapSnapshotsComparator::~HeapSnapshotsComparator() {
 
 HeapSnapshotsDiff* HeapSnapshotsComparator::Compare(HeapSnapshot* snapshot1,
                                                     HeapSnapshot* snapshot2) {
-  HeapSnapshotsDiff* diff = new HeapSnapshotsDiff(snapshot1, snapshot2);
-  diffs_.Add(diff);
   List<HeapEntry*>* entries1 = snapshot1->GetSortedEntriesList();
   List<HeapEntry*>* entries2 = snapshot2->GetSortedEntriesList();
   int i = 0, j = 0;
@@ -1810,17 +2069,33 @@ HeapSnapshotsDiff* HeapSnapshotsComparator::Compare(HeapSnapshot* snapshot1,
 
   snapshot1->ClearPaint();
   snapshot1->root()->PaintAllReachable();
+  snapshot2->ClearPaint();
+  snapshot2->root()->PaintAllReachable();
+  int reachable_deleted_entries = 0, reachable_added_entries = 0;
+  for (int i = 0; i < deleted_entries.length(); ++i) {
+    HeapEntry* entry = deleted_entries[i];
+    if (entry->painted_reachable()) ++reachable_deleted_entries;
+  }
+  for (int i = 0; i < added_entries.length(); ++i) {
+    HeapEntry* entry = added_entries[i];
+    if (entry->painted_reachable()) ++reachable_added_entries;
+  }
+
+  HeapSnapshotsDiff* diff = new HeapSnapshotsDiff(snapshot1, snapshot2);
+  diffs_.Add(diff);
+  diff->CreateRoots(reachable_added_entries, reachable_deleted_entries);
+
+  int del_child_index = 0, deleted_entry_index = 1;
   for (int i = 0; i < deleted_entries.length(); ++i) {
     HeapEntry* entry = deleted_entries[i];
     if (entry->painted_reachable())
-      diff->AddDeletedEntry(entry);
+      diff->AddDeletedEntry(del_child_index++, deleted_entry_index++, entry);
   }
-  snapshot2->ClearPaint();
-  snapshot2->root()->PaintAllReachable();
+  int add_child_index = 0, added_entry_index = 1;
   for (int i = 0; i < added_entries.length(); ++i) {
     HeapEntry* entry = added_entries[i];
     if (entry->painted_reachable())
-      diff->AddAddedEntry(entry);
+      diff->AddAddedEntry(add_child_index++, added_entry_index++, entry);
   }
   return diff;
 }

src/profile-generator.h

@@ -423,167 +423,194 @@ class ProfileGenerator {
 };
 
 
-class HeapSnapshot;
 class HeapEntry;
 
-
-class HeapGraphEdge {
+class HeapGraphEdge BASE_EMBEDDED {
  public:
   enum Type {
-    CONTEXT_VARIABLE = v8::HeapGraphEdge::CONTEXT_VARIABLE,
-    ELEMENT = v8::HeapGraphEdge::ELEMENT,
-    PROPERTY = v8::HeapGraphEdge::PROPERTY,
-    INTERNAL = v8::HeapGraphEdge::INTERNAL
+    kContextVariable = v8::HeapGraphEdge::kContextVariable,
+    kElement = v8::HeapGraphEdge::kElement,
+    kProperty = v8::HeapGraphEdge::kProperty,
+    kInternal = v8::HeapGraphEdge::kInternal
   };
 
-  HeapGraphEdge(Type type, const char* name, HeapEntry* from, HeapEntry* to);
-  HeapGraphEdge(int index, HeapEntry* from, HeapEntry* to);
+  HeapGraphEdge() { }
+  void Init(int child_index, Type type, const char* name, HeapEntry* to);
+  void Init(int child_index, int index, HeapEntry* to);
 
-  Type type() const { return type_; }
-  int index() const {
-    ASSERT(type_ == ELEMENT);
+  Type type() { return type_; }
+  int index() {
+    ASSERT(type_ == kElement);
     return index_;
   }
-  const char* name() const {
-    ASSERT(type_ == CONTEXT_VARIABLE || type_ == PROPERTY || type_ == INTERNAL);
+  const char* name() {
+    ASSERT(type_ == kContextVariable
+           || type_ == kProperty
+           || type_ == kInternal);
     return name_;
   }
-  HeapEntry* from() const { return from_; }
-  HeapEntry* to() const { return to_; }
+  HeapEntry* to() { return to_; }
+
+  HeapEntry* From();
 
  private:
-  Type type_;
+  int child_index_ : 30;
+  Type type_ : 2;
   union {
     int index_;
     const char* name_;
   };
-  HeapEntry* from_;
   HeapEntry* to_;
 
   DISALLOW_COPY_AND_ASSIGN(HeapGraphEdge);
 };
 
 
-class HeapGraphPath;
 class CachedHeapGraphPath;
+class HeapGraphPath;
+class HeapSnapshot;
 
-class HeapEntry {
+// HeapEntry instances represent an entity from the heap (or a special
+// virtual node, e.g. root). To make heap snapshots more compact,
+// HeapEntries has a special memory layout (no Vectors or Lists used):
+//
+//   +-----------------+
+//        HeapEntry
+//   +-----------------+
+//      HeapGraphEdge    |
+//           ...         } children_count
+//      HeapGraphEdge    |
+//   +-----------------+
+//      HeapGraphEdge*   |
+//           ...         } retainers_count
+//      HeapGraphEdge*   |
+//   +-----------------+
+//
+// In a HeapSnapshot, all entries are hand-allocated in a continuous array
+// of raw bytes.
+//
+class HeapEntry BASE_EMBEDDED {
  public:
   enum Type {
-    INTERNAL = v8::HeapGraphNode::INTERNAL,
-    ARRAY = v8::HeapGraphNode::ARRAY,
-    STRING = v8::HeapGraphNode::STRING,
-    OBJECT = v8::HeapGraphNode::OBJECT,
-    CODE = v8::HeapGraphNode::CODE,
-    CLOSURE = v8::HeapGraphNode::CLOSURE
+    kInternal = v8::HeapGraphNode::kInternal,
+    kArray = v8::HeapGraphNode::kArray,
+    kString = v8::HeapGraphNode::kString,
+    kObject = v8::HeapGraphNode::kObject,
+    kCode = v8::HeapGraphNode::kCode,
+    kClosure = v8::HeapGraphNode::kClosure
   };
 
-  explicit HeapEntry(HeapSnapshot* snapshot)
-      : snapshot_(snapshot),
-        visited_(false),
-        type_(INTERNAL),
-        name_(""),
-        id_(0),
-        next_auto_index_(0),
-        self_size_(0),
-        security_token_id_(TokenEnumerator::kNoSecurityToken),
-        children_(1),
-        retainers_(0),
-        retaining_paths_(0),
-        total_size_(kUnknownSize),
-        non_shared_total_size_(kUnknownSize),
-        painted_(kUnpainted) { }
-  HeapEntry(HeapSnapshot* snapshot,
+  HeapEntry() { }
+  void Init(HeapSnapshot* snapshot, int children_count, int retainers_count);
+  void Init(HeapSnapshot* snapshot,
             Type type,
             const char* name,
             uint64_t id,
             int self_size,
-            int security_token_id)
-      : snapshot_(snapshot),
-        visited_(false),
-        type_(type),
-        name_(name),
-        id_(id),
-        next_auto_index_(1),
-        self_size_(self_size),
-        security_token_id_(security_token_id),
-        children_(4),
-        retainers_(4),
-        retaining_paths_(4),
-        total_size_(kUnknownSize),
-        non_shared_total_size_(kUnknownSize),
-        painted_(kUnpainted) { }
-  ~HeapEntry();
-
-  bool visited() const { return visited_; }
-  Type type() const { return type_; }
-  const char* name() const { return name_; }
-  uint64_t id() const { return id_; }
-  int self_size() const { return self_size_; }
-  int security_token_id() const { return security_token_id_; }
-  bool painted_reachable() { return painted_ == kPaintReachable; }
+            int children_count,
+            int retainers_count);
+
+  HeapSnapshot* snapshot() { return snapshot_; }
+  Type type() { return type_; }
+  const char* name() { return name_; }
+  uint64_t id() { return id_; }
+  int self_size() { return self_size_; }
+
+  Vector<HeapGraphEdge> children() {
+    return Vector<HeapGraphEdge>(children_arr(), children_count_); }
+  Vector<HeapGraphEdge*> retainers() {
+    return Vector<HeapGraphEdge*>(retainers_arr(), retainers_count_); }
+  List<HeapGraphPath*>* GetRetainingPaths();
+
+  void clear_paint() { painted_ = kUnpainted; }
+  bool painted_reachable() { return painted_ == kPainted; }
+  void paint_reachable() {
+    ASSERT(painted_ == kUnpainted);
+    painted_ = kPainted;
+  }
   bool not_painted_reachable_from_others() {
-    return painted_ != kPaintReachableFromOthers;
+    return painted_ != kPaintedReachableFromOthers;
+  }
+  void paint_reachable_from_others() {
+    painted_ = kPaintedReachableFromOthers;
   }
-  const List<HeapGraphEdge*>* children() const { return &children_; }
-  const List<HeapGraphEdge*>* retainers() const { return &retainers_; }
-  const List<HeapGraphPath*>* GetRetainingPaths();
-
   template<class Visitor>
   void ApplyAndPaintAllReachable(Visitor* visitor);
-
-  void ClearPaint() { painted_ = kUnpainted; }
-  void CutEdges();
-  void MarkAsVisited() { visited_ = true; }
   void PaintAllReachable();
-  void PaintReachable() {
-    ASSERT(painted_ == kUnpainted);
-    painted_ = kPaintReachable;
-  }
-  void PaintReachableFromOthers() { painted_ = kPaintReachableFromOthers; }
-  void SetClosureReference(const char* name, HeapEntry* entry);
-  void SetElementReference(int index, HeapEntry* entry);
-  void SetInternalReference(const char* name, HeapEntry* entry);
-  void SetPropertyReference(const char* name, HeapEntry* entry);
-  void SetAutoIndexReference(HeapEntry* entry);
-  void SetUnidirAutoIndexReference(HeapEntry* entry);
 
-  int TotalSize();
-  int NonSharedTotalSize();
+  void SetElementReference(
+      int child_index, int index, HeapEntry* entry, int retainer_index);
+  void SetNamedReference(HeapGraphEdge::Type type,
+                         int child_index,
+                         const char* name,
+                         HeapEntry* entry,
+                         int retainer_index);
+  void SetUnidirElementReference(int child_index, int index, HeapEntry* entry);
+
+  int EntrySize() { return EntriesSize(1, children_count_, retainers_count_); }
+  int ReachableSize();
+  int RetainedSize();
 
   void Print(int max_depth, int indent);
 
- private:
-  void AddEdge(HeapGraphEdge* edge);
-  int CalculateTotalSize();
-  int CalculateNonSharedTotalSize();
-  void FindRetainingPaths(HeapEntry* node, CachedHeapGraphPath* prev_path);
-  void RemoveChild(HeapGraphEdge* edge);
-  void RemoveRetainer(HeapGraphEdge* edge);
+  static int EntriesSize(int entries_count,
+                         int children_count,
+                         int retainers_count);
 
+ private:
+  HeapGraphEdge* children_arr() {
+    return reinterpret_cast<HeapGraphEdge*>(this + 1);
+  }
+  HeapGraphEdge** retainers_arr() {
+    return reinterpret_cast<HeapGraphEdge**>(children_arr() + children_count_);
+  }
   const char* TypeAsString();
 
   HeapSnapshot* snapshot_;
-  bool visited_;
-  Type type_;
+  unsigned painted_: 2;
+  Type type_: 3;
+  // The calculated data is stored in HeapSnapshot in HeapEntryCalculatedData
+  // entries. See AddCalculatedData and GetCalculatedData.
+  int calculated_data_index_: 27;
   const char* name_;
   uint64_t id_;
-  int next_auto_index_;
   int self_size_;
-  int security_token_id_;
-  List<HeapGraphEdge*> children_;
-  List<HeapGraphEdge*> retainers_;
-  List<HeapGraphPath*> retaining_paths_;
-  int total_size_;
-  int non_shared_total_size_;
-  int painted_;
+  int children_count_;
+  int retainers_count_;
+
+  static const unsigned kUnpainted = 0;
+  static const unsigned kPainted = 1;
+  static const unsigned kPaintedReachableFromOthers = 2;
+  static const int kNoCalculatedData = -1;
+
+  DISALLOW_COPY_AND_ASSIGN(HeapEntry);
+};
+
+
+class HeapEntryCalculatedData {
+ public:
+  HeapEntryCalculatedData()
+      : retaining_paths_(NULL),
+        reachable_size_(kUnknownSize),
+        retained_size_(kUnknownSize) {
+  }
+  void Dispose();
+
+  List<HeapGraphPath*>* GetRetainingPaths(HeapEntry* entry);
+  int ReachableSize(HeapEntry* entry);
+  int RetainedSize(HeapEntry* entry);
+
+ private:
+  void CalculateSizes(HeapEntry* entry);
+  void FindRetainingPaths(HeapEntry* entry, CachedHeapGraphPath* prev_path);
+
+  List<HeapGraphPath*>* retaining_paths_;
+  int reachable_size_;
+  int retained_size_;
 
   static const int kUnknownSize = -1;
-  static const int kUnpainted = 0;
-  static const int kPaintReachable = 1;
-  static const int kPaintReachableFromOthers = 2;
 
-  DISALLOW_IMPLICIT_CONSTRUCTORS(HeapEntry);
+  // Allow generated copy constructor and assignment operator.
 };
 
 
@@ -595,7 +622,7 @@ class HeapGraphPath {
 
   void Add(HeapGraphEdge* edge) { path_.Add(edge); }
   void Set(int index, HeapGraphEdge* edge) { path_[index] = edge; }
-  const List<HeapGraphEdge*>* path() const { return &path_; }
+  const List<HeapGraphEdge*>* path() { return &path_; }
 
   void Print();
 
@@ -606,39 +633,6 @@ class HeapGraphPath {
 };
 
 
-class HeapEntriesMap {
- public:
-  HeapEntriesMap();
-  ~HeapEntriesMap();
-
-  void Alias(HeapObject* object, HeapEntry* entry);
-  void Apply(void (HeapEntry::*Func)(void));
-  template<class Visitor>
-  void Apply(Visitor* visitor);
-  HeapEntry* Map(HeapObject* object);
-  void Pair(HeapObject* object, HeapEntry* entry);
-
-  uint32_t capacity() { return entries_.capacity(); }
-
- private:
-  INLINE(uint32_t Hash(HeapObject* object)) {
-    return static_cast<uint32_t>(reinterpret_cast<intptr_t>(object));
-  }
-  INLINE(static bool HeapObjectsMatch(void* key1, void* key2)) {
-    return key1 == key2;
-  }
-  INLINE(bool IsAlias(void* ptr)) {
-    return reinterpret_cast<intptr_t>(ptr) & kAliasTag;
-  }
-
-  static const intptr_t kAliasTag = 1;
-
-  HashMap entries_;
-
-  DISALLOW_COPY_AND_ASSIGN(HeapEntriesMap);
-};
-
-
 class HeapSnapshotsCollection;
 class HeapSnapshotsDiff;
 
@@ -653,53 +647,50 @@ class HeapSnapshot {
                const char* title,
                unsigned uid);
   ~HeapSnapshot();
-  void ClearPaint();
-  void CutObjectsFromForeignSecurityContexts();
-  HeapEntry* GetEntry(Object* object);
-  void SetClosureReference(
-      HeapEntry* parent, String* reference_name, Object* child);
-  void SetElementReference(HeapEntry* parent, int index, Object* child);
-  void SetInternalReference(
-      HeapEntry* parent, const char* reference_name, Object* child);
-  void SetPropertyReference(
-      HeapEntry* parent, String* reference_name, Object* child);
 
-  INLINE(const char* title() const) { return title_; }
-  INLINE(unsigned uid() const) { return uid_; }
-  const HeapEntry* const_root() const { return &root_; }
-  HeapEntry* root() { return &root_; }
-  template<class Visitor>
-  void IterateEntries(Visitor* visitor) { entries_.Apply(visitor); }
-  List<HeapEntry*>* GetSortedEntriesList();
+  HeapSnapshotsCollection* collection() { return collection_; }
+  const char* title() { return title_; }
+  unsigned uid() { return uid_; }
+  HeapEntry* root() { return entries_[root_entry_index_]; }
+
+  void AllocateEntries(
+      int entries_count, int children_count, int retainers_count);
+  HeapEntry* AddEntry(
+      HeapObject* object, int children_count, int retainers_count);
+  bool WillAddEntry(HeapObject* object);
+  int AddCalculatedData();
+  HeapEntryCalculatedData& GetCalculatedData(int index) {
+    return calculated_data_[index];
+  }
+  void ClearPaint();
   HeapSnapshotsDiff* CompareWith(HeapSnapshot* snapshot);
+  List<HeapEntry*>* GetSortedEntriesList();
+  template<class Visitor>
+  void IterateEntries(Visitor* visitor) { entries_.Iterate(visitor); }
 
   void Print(int max_depth);
+  void PrintEntriesSize();
+
+  static HeapObject *const kInternalRootObject;
 
  private:
-  HeapEntry* AddEntry(HeapObject* object, HeapEntry::Type type) {
-    return AddEntry(object, type, "");
-  }
-  HeapEntry* AddEntry(
-      HeapObject* object, HeapEntry::Type type, const char* name);
-  void AddEntryAlias(HeapObject* object, HeapEntry* entry) {
-    entries_.Alias(object, entry);
-  }
-  HeapEntry* FindEntry(HeapObject* object) {
-    return entries_.Map(object);
-  }
-  int GetGlobalSecurityToken();
-  int GetObjectSecurityToken(HeapObject* obj);
+  HeapEntry* AddEntry(HeapObject* object,
+                      HeapEntry::Type type,
+                      const char* name,
+                      int children_count,
+                      int retainers_count);
+  HeapEntry* GetNextEntryToInit();
   static int GetObjectSize(HeapObject* obj);
   static int CalculateNetworkSize(JSObject* obj);
 
   HeapSnapshotsCollection* collection_;
   const char* title_;
   unsigned uid_;
-  HeapEntry root_;
-  // Mapping from HeapObject* pointers to HeapEntry* pointers.
-  HeapEntriesMap entries_;
-  // Entries sorted by id.
-  List<HeapEntry*>* sorted_entries_;
+  int root_entry_index_;
+  char* raw_entries_;
+  List<HeapEntry*> entries_;
+  bool entries_sorted_;
+  List<HeapEntryCalculatedData> calculated_data_;
 
   DISALLOW_COPY_AND_ASSIGN(HeapSnapshot);
 };
@@ -748,30 +739,36 @@ class HeapSnapshotsDiff {
   HeapSnapshotsDiff(HeapSnapshot* snapshot1, HeapSnapshot* snapshot2)
       : snapshot1_(snapshot1),
         snapshot2_(snapshot2),
-        additions_root_(new HeapEntry(snapshot2)),
-        deletions_root_(new HeapEntry(snapshot1)) { }
+        raw_additions_root_(NULL),
+        raw_deletions_root_(NULL) { }
 
   ~HeapSnapshotsDiff() {
-    delete deletions_root_;
-    delete additions_root_;
+    DeleteArray(raw_deletions_root_);
+    DeleteArray(raw_additions_root_);
   }
 
-  void AddAddedEntry(HeapEntry* entry) {
-    additions_root_->SetUnidirAutoIndexReference(entry);
+  void AddAddedEntry(int child_index, int index, HeapEntry* entry) {
+    additions_root()->SetUnidirElementReference(child_index, index, entry);
   }
 
-  void AddDeletedEntry(HeapEntry* entry) {
-    deletions_root_->SetUnidirAutoIndexReference(entry);
+  void AddDeletedEntry(int child_index, int index, HeapEntry* entry) {
+    deletions_root()->SetUnidirElementReference(child_index, index, entry);
   }
 
-  const HeapEntry* additions_root() const { return additions_root_; }
-  const HeapEntry* deletions_root() const { return deletions_root_; }
+  void CreateRoots(int additions_count, int deletions_count);
+
+  HeapEntry* additions_root() {
+    return reinterpret_cast<HeapEntry*>(raw_additions_root_);
+  }
+  HeapEntry* deletions_root() {
+    return reinterpret_cast<HeapEntry*>(raw_deletions_root_);
+  }
 
  private:
   HeapSnapshot* snapshot1_;
   HeapSnapshot* snapshot2_;
-  HeapEntry* additions_root_;
-  HeapEntry* deletions_root_;
+  char* raw_additions_root_;
+  char* raw_deletions_root_;
 
   DISALLOW_COPY_AND_ASSIGN(HeapSnapshotsDiff);
 };
@@ -830,18 +827,123 @@ class HeapSnapshotsCollection {
 };
 
 
+// The HeapEntriesMap instance is used to track a mapping between
+// real heap objects and their representations in heap snapshots.
+class HeapEntriesMap {
+ public:
+  HeapEntriesMap();
+  ~HeapEntriesMap();
+
+  // Aliasing is used for skipping intermediate proxy objects, like
+  // JSGlobalPropertyCell.
+  void Alias(HeapObject* from, HeapObject* to);
+  HeapEntry* Map(HeapObject* object);
+  void Pair(HeapObject* object, HeapEntry* entry);
+  void CountReference(HeapObject* from, HeapObject* to,
+                      int* prev_children_count = NULL,
+                      int* prev_retainers_count = NULL);
+  template<class Visitor>
+  void UpdateEntries(Visitor* visitor);
+
+  int entries_count() { return entries_count_; }
+  int total_children_count() { return total_children_count_; }
+  int total_retainers_count() { return total_retainers_count_; }
+
+ private:
+  struct EntryInfo {
+    explicit EntryInfo(HeapEntry* entry)
+        : entry(entry), children_count(0), retainers_count(0) { }
+    HeapEntry* entry;
+    int children_count;
+    int retainers_count;
+  };
+
+  uint32_t Hash(HeapObject* object) {
+    return static_cast<uint32_t>(reinterpret_cast<intptr_t>(object));
+  }
+  static bool HeapObjectsMatch(void* key1, void* key2) { return key1 == key2; }
+
+  bool IsAlias(void* ptr) {
+    return reinterpret_cast<intptr_t>(ptr) & kAliasTag;
+  }
+  void* MakeAlias(void* ptr) {
+    return reinterpret_cast<void*>(reinterpret_cast<intptr_t>(ptr) | kAliasTag);
+  }
+  void* Unalias(void* ptr) {
+    return reinterpret_cast<void*>(
+        reinterpret_cast<intptr_t>(ptr) & (~kAliasTag));
+  }
+
+  HashMap entries_;
+  int entries_count_;
+  int total_children_count_;
+  int total_retainers_count_;
+
+  static const intptr_t kAliasTag = 1;
+
+  DISALLOW_COPY_AND_ASSIGN(HeapEntriesMap);
+};
+
+
 class HeapSnapshotGenerator {
  public:
+  class SnapshotFillerInterface {
+   public:
+    virtual ~SnapshotFillerInterface() { }
+    virtual HeapEntry* AddEntry(HeapObject* obj) = 0;
+    virtual void SetElementReference(HeapObject* parent_obj,
+                                     HeapEntry* parent_entry,
+                                     int index,
+                                     Object* child_obj,
+                                     HeapEntry* child_entry) = 0;
+    virtual void SetNamedReference(HeapGraphEdge::Type type,
+                                   HeapObject* parent_obj,
+                                   HeapEntry* parent_entry,
+                                   const char* reference_name,
+                                   Object* child_obj,
+                                   HeapEntry* child_entry) = 0;
+    virtual void SetRootReference(Object* child_obj,
+                                  HeapEntry* child_entry) = 0;
+
+    static HeapEntry *const kHeapEntryPlaceholder;
+  };
+
   explicit HeapSnapshotGenerator(HeapSnapshot* snapshot);
   void GenerateSnapshot();
 
  private:
+  HeapEntry* GetEntry(Object* obj);
+  int GetGlobalSecurityToken();
+  int GetObjectSecurityToken(HeapObject* obj);
   void ExtractReferences(HeapObject* obj);
   void ExtractClosureReferences(JSObject* js_obj, HeapEntry* entry);
   void ExtractPropertyReferences(JSObject* js_obj, HeapEntry* entry);
   void ExtractElementReferences(JSObject* js_obj, HeapEntry* entry);
+  void SetClosureReference(HeapObject* parent_obj,
+                           HeapEntry* parent,
+                           String* reference_name,
+                           Object* child);
+  void SetElementReference(HeapObject* parent_obj,
+                           HeapEntry* parent,
+                           int index,
+                           Object* child);
+  void SetInternalReference(HeapObject* parent_obj,
+                            HeapEntry* parent,
+                            const char* reference_name,
+                            Object* child);
+  void SetPropertyReference(HeapObject* parent_obj,
+                            HeapEntry* parent,
+                            String* reference_name,
+                            Object* child);
+  void SetRootReference(Object* child);
 
   HeapSnapshot* snapshot_;
+  HeapSnapshotsCollection* collection_;
+  // Mapping from HeapObject* pointers to HeapEntry* pointers.
+  HeapEntriesMap entries_;
+  SnapshotFillerInterface* filler_;
+
+  friend class IndexedReferencesExtractor;
 
   DISALLOW_COPY_AND_ASSIGN(HeapSnapshotGenerator);
 };

test/cctest/test-heap-profiler.cc

@@ -396,20 +396,17 @@ class NamedEntriesDetector {
         has_A2(false), has_B2(false), has_C2(false) {
   }
 
-  void Apply(i::HeapEntry* entry) {
-    const char* node_name = entry->name();
-    if (strcmp("A1", node_name) == 0
-        && entry->GetRetainingPaths()->length() > 0) has_A1 = true;
-    if (strcmp("B1", node_name) == 0
-        && entry->GetRetainingPaths()->length() > 0) has_B1 = true;
-    if (strcmp("C1", node_name) == 0
-        && entry->GetRetainingPaths()->length() > 0) has_C1 = true;
-    if (strcmp("A2", node_name) == 0
-        && entry->GetRetainingPaths()->length() > 0) has_A2 = true;
-    if (strcmp("B2", node_name) == 0
-        && entry->GetRetainingPaths()->length() > 0) has_B2 = true;
-    if (strcmp("C2", node_name) == 0
-        && entry->GetRetainingPaths()->length() > 0) has_C2 = true;
+  void Apply(i::HeapEntry** entry_ptr) {
+    if (IsReachableNodeWithName(*entry_ptr, "A1")) has_A1 = true;
+    if (IsReachableNodeWithName(*entry_ptr, "B1")) has_B1 = true;
+    if (IsReachableNodeWithName(*entry_ptr, "C1")) has_C1 = true;
+    if (IsReachableNodeWithName(*entry_ptr, "A2")) has_A2 = true;
+    if (IsReachableNodeWithName(*entry_ptr, "B2")) has_B2 = true;
+    if (IsReachableNodeWithName(*entry_ptr, "C2")) has_C2 = true;
+  }
+
+  static bool IsReachableNodeWithName(i::HeapEntry* entry, const char* name) {
+    return strcmp(name, entry->name()) == 0 && entry->painted_reachable();
   }
 
   bool has_A1;
@@ -460,7 +457,7 @@ static bool HasString(const v8::HeapGraphNode* node, const char* contents) {
   for (int i = 0, count = node->GetChildrenCount(); i < count; ++i) {
     const v8::HeapGraphEdge* prop = node->GetChild(i);
     const v8::HeapGraphNode* node = prop->GetToNode();
-    if (node->GetType() == v8::HeapGraphNode::STRING) {
+    if (node->GetType() == v8::HeapGraphNode::kString) {
       v8::String::AsciiValue node_name(node->GetName());
       if (strcmp(contents, *node_name) == 0) return true;
     }
@@ -496,26 +493,34 @@ TEST(HeapSnapshot) {
       "var c2 = new C2(a2);");
   const v8::HeapSnapshot* snapshot_env2 =
       v8::HeapProfiler::TakeSnapshot(v8::String::New("env2"));
+  i::HeapSnapshot* i_snapshot_env2 =
+      const_cast<i::HeapSnapshot*>(
+          reinterpret_cast<const i::HeapSnapshot*>(snapshot_env2));
   const v8::HeapGraphNode* global_env2 = GetGlobalObject(snapshot_env2);
+  // Paint all nodes reachable from global object.
+  i_snapshot_env2->ClearPaint();
+  const_cast<i::HeapEntry*>(
+      reinterpret_cast<const i::HeapEntry*>(global_env2))->PaintAllReachable();
 
   // Verify, that JS global object of env2 doesn't have '..1'
   // properties, but has '..2' properties.
-  CHECK_EQ(NULL, GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "a1"));
-  CHECK_EQ(NULL, GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "b1_1"));
-  CHECK_EQ(NULL, GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "b1_2"));
-  CHECK_EQ(NULL, GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "c1"));
+  CHECK_EQ(NULL, GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "a1"));
+  CHECK_EQ(
+      NULL, GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "b1_1"));
+  CHECK_EQ(
+      NULL, GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "b1_2"));
+  CHECK_EQ(NULL, GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "c1"));
   const v8::HeapGraphNode* a2_node =
-      GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "a2");
+      GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "a2");
   CHECK_NE(NULL, a2_node);
-  CHECK_NE(NULL, GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "b2_1"));
-  CHECK_NE(NULL, GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "b2_2"));
-  CHECK_NE(NULL, GetProperty(global_env2, v8::HeapGraphEdge::PROPERTY, "c2"));
+  CHECK_NE(
+      NULL, GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "b2_1"));
+  CHECK_NE(
+      NULL, GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "b2_2"));
+  CHECK_NE(NULL, GetProperty(global_env2, v8::HeapGraphEdge::kProperty, "c2"));
 
   // Verify that anything related to '[ABC]1' is not reachable.
   NamedEntriesDetector det;
-  i::HeapSnapshot* i_snapshot_env2 =
-      const_cast<i::HeapSnapshot*>(
-          reinterpret_cast<const i::HeapSnapshot*>(snapshot_env2));
   i_snapshot_env2->IterateEntries(&det);
   CHECK(!det.has_A1);
   CHECK(!det.has_B1);
@@ -539,7 +544,7 @@ TEST(HeapSnapshot) {
     const v8::HeapGraphEdge* last_edge = path->GetEdge(edges_count - 1);
     v8::String::AsciiValue last_edge_name(last_edge->GetName());
     if (strcmp("a2", *last_edge_name) == 0
-        && last_edge->GetType() == v8::HeapGraphEdge::PROPERTY) {
+        && last_edge->GetType() == v8::HeapGraphEdge::kProperty) {
       has_global_obj_a2_ref = true;
       continue;
     }
@@ -547,19 +552,19 @@ TEST(HeapSnapshot) {
     const v8::HeapGraphEdge* prev_edge = path->GetEdge(edges_count - 2);
     v8::String::AsciiValue prev_edge_name(prev_edge->GetName());
     if (strcmp("x1", *last_edge_name) == 0
-        && last_edge->GetType() == v8::HeapGraphEdge::PROPERTY
+        && last_edge->GetType() == v8::HeapGraphEdge::kProperty
         && strcmp("c2", *prev_edge_name) == 0) has_c2_x1_ref = true;
     if (strcmp("x2", *last_edge_name) == 0
-        && last_edge->GetType() == v8::HeapGraphEdge::PROPERTY
+        && last_edge->GetType() == v8::HeapGraphEdge::kProperty
         && strcmp("c2", *prev_edge_name) == 0) has_c2_x2_ref = true;
     if (strcmp("1", *last_edge_name) == 0
-        && last_edge->GetType() == v8::HeapGraphEdge::ELEMENT
+        && last_edge->GetType() == v8::HeapGraphEdge::kElement
         && strcmp("c2", *prev_edge_name) == 0) has_c2_1_ref = true;
     if (strcmp("x", *last_edge_name) == 0
-        && last_edge->GetType() == v8::HeapGraphEdge::CONTEXT_VARIABLE
+        && last_edge->GetType() == v8::HeapGraphEdge::kContextVariable
         && strcmp("b2_1", *prev_edge_name) == 0) has_b2_1_x_ref = true;
     if (strcmp("x", *last_edge_name) == 0
-        && last_edge->GetType() == v8::HeapGraphEdge::CONTEXT_VARIABLE
+        && last_edge->GetType() == v8::HeapGraphEdge::kContextVariable
         && strcmp("b2_2", *prev_edge_name) == 0) has_b2_2_x_ref = true;
   }
   CHECK(has_global_obj_a2_ref);
@@ -571,6 +576,73 @@ TEST(HeapSnapshot) {
 }
 
 
+TEST(HeapSnapshotObjectSizes) {
+  v8::HandleScope scope;
+  LocalContext env;
+
+  //   -a-> X1 --a
+  // x -b-> X2 <-|
+  CompileAndRunScript(
+      "function X(a, b) { this.a = a; this.b = b; }\n"
+      "x = new X(new X(), new X());\n"
+      "x.a.a = x.b;");
+  const v8::HeapSnapshot* snapshot =
+      v8::HeapProfiler::TakeSnapshot(v8::String::New("sizes"));
+  const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
+  const v8::HeapGraphNode* x =
+      GetProperty(global, v8::HeapGraphEdge::kProperty, "x");
+  CHECK_NE(NULL, x);
+  const v8::HeapGraphNode* x_prototype =
+      GetProperty(x, v8::HeapGraphEdge::kProperty, "prototype");
+  CHECK_NE(NULL, x_prototype);
+  const v8::HeapGraphNode* x1 =
+      GetProperty(x, v8::HeapGraphEdge::kProperty, "a");
+  CHECK_NE(NULL, x1);
+  const v8::HeapGraphNode* x2 =
+      GetProperty(x, v8::HeapGraphEdge::kProperty, "b");
+  CHECK_NE(NULL, x2);
+  CHECK_EQ(
+      x->GetSelfSize() * 3,
+      x->GetReachableSize() - x_prototype->GetReachableSize());
+  CHECK_EQ(
+      x->GetSelfSize() * 3 + x_prototype->GetSelfSize(), x->GetRetainedSize());
+  CHECK_EQ(
+      x1->GetSelfSize() * 2,
+      x1->GetReachableSize() - x_prototype->GetReachableSize());
+  CHECK_EQ(
+      x1->GetSelfSize(), x1->GetRetainedSize());
+  CHECK_EQ(
+      x2->GetSelfSize(),
+      x2->GetReachableSize() - x_prototype->GetReachableSize());
+  CHECK_EQ(
+      x2->GetSelfSize(), x2->GetRetainedSize());
+}
+
+
+TEST(HeapSnapshotEntryChildren) {
+  v8::HandleScope scope;
+  LocalContext env;
+
+  CompileAndRunScript(
+      "function A() { }\n"
+      "a = new A;");
+  const v8::HeapSnapshot* snapshot =
+      v8::HeapProfiler::TakeSnapshot(v8::String::New("children"));
+  const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
+  for (int i = 0, count = global->GetChildrenCount(); i < count; ++i) {
+    const v8::HeapGraphEdge* prop = global->GetChild(i);
+    CHECK_EQ(global, prop->GetFromNode());
+  }
+  const v8::HeapGraphNode* a =
+      GetProperty(global, v8::HeapGraphEdge::kProperty, "a");
+  CHECK_NE(NULL, a);
+  for (int i = 0, count = a->GetChildrenCount(); i < count; ++i) {
+    const v8::HeapGraphEdge* prop = a->GetChild(i);
+    CHECK_EQ(a, prop->GetFromNode());
+  }
+}
+
+
 TEST(HeapSnapshotCodeObjects) {
   v8::HandleScope scope;
   LocalContext env;
@@ -584,20 +656,20 @@ TEST(HeapSnapshotCodeObjects) {
 
   const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
   const v8::HeapGraphNode* compiled =
-      GetProperty(global, v8::HeapGraphEdge::PROPERTY, "compiled");
+      GetProperty(global, v8::HeapGraphEdge::kProperty, "compiled");
   CHECK_NE(NULL, compiled);
-  CHECK_EQ(v8::HeapGraphNode::CLOSURE, compiled->GetType());
+  CHECK_EQ(v8::HeapGraphNode::kClosure, compiled->GetType());
   const v8::HeapGraphNode* lazy =
-      GetProperty(global, v8::HeapGraphEdge::PROPERTY, "lazy");
+      GetProperty(global, v8::HeapGraphEdge::kProperty, "lazy");
   CHECK_NE(NULL, lazy);
-  CHECK_EQ(v8::HeapGraphNode::CLOSURE, lazy->GetType());
+  CHECK_EQ(v8::HeapGraphNode::kClosure, lazy->GetType());
 
   // Find references to code.
   const v8::HeapGraphNode* compiled_code =
-      GetProperty(compiled, v8::HeapGraphEdge::INTERNAL, "code");
+      GetProperty(compiled, v8::HeapGraphEdge::kInternal, "code");
   CHECK_NE(NULL, compiled_code);
   const v8::HeapGraphNode* lazy_code =
-      GetProperty(lazy, v8::HeapGraphEdge::INTERNAL, "code");
+      GetProperty(lazy, v8::HeapGraphEdge::kInternal, "code");
   CHECK_NE(NULL, lazy_code);
 
   // Verify that non-compiled code doesn't contain references to "x"
@@ -607,7 +679,7 @@ TEST(HeapSnapshotCodeObjects) {
   for (int i = 0, count = compiled_code->GetChildrenCount(); i < count; ++i) {
     const v8::HeapGraphEdge* prop = compiled_code->GetChild(i);
     const v8::HeapGraphNode* node = prop->GetToNode();
-    if (node->GetType() == v8::HeapGraphNode::ARRAY) {
+    if (node->GetType() == v8::HeapGraphNode::kArray) {
       if (HasString(node, "x")) {
         compiled_references_x = true;
         break;
@@ -617,7 +689,7 @@ TEST(HeapSnapshotCodeObjects) {
   for (int i = 0, count = lazy_code->GetChildrenCount(); i < count; ++i) {
     const v8::HeapGraphEdge* prop = lazy_code->GetChild(i);
     const v8::HeapGraphNode* node = prop->GetToNode();
-    if (node->GetType() == v8::HeapGraphNode::ARRAY) {
+    if (node->GetType() == v8::HeapGraphNode::kArray) {
       if (HasString(node, "x")) {
         lazy_references_x = true;
         break;
@@ -634,11 +706,8 @@ TEST(HeapSnapshotCodeObjects) {
 // them to a signed type.
 #define CHECK_EQ_UINT64_T(a, b) \
   CHECK_EQ(static_cast<int64_t>(a), static_cast<int64_t>(b))
-#define CHECK_NE_UINT64_T(a, b) do              \
-  {                                             \
-    bool ne = a != b;                           \
-    CHECK(ne);                                  \
-  } while (false)
+#define CHECK_NE_UINT64_T(a, b) \
+  CHECK((a) != (b))  // NOLINT
 
 TEST(HeapEntryIdsAndGC) {
   v8::HandleScope scope;
@@ -662,27 +731,35 @@ TEST(HeapEntryIdsAndGC) {
   CHECK_NE_UINT64_T(0, global1->GetId());
   CHECK_EQ_UINT64_T(global1->GetId(), global2->GetId());
   const v8::HeapGraphNode* A1 =
-      GetProperty(global1, v8::HeapGraphEdge::PROPERTY, "A");
+      GetProperty(global1, v8::HeapGraphEdge::kProperty, "A");
+  CHECK_NE(NULL, A1);
   const v8::HeapGraphNode* A2 =
-      GetProperty(global2, v8::HeapGraphEdge::PROPERTY, "A");
+      GetProperty(global2, v8::HeapGraphEdge::kProperty, "A");
+  CHECK_NE(NULL, A2);
   CHECK_NE_UINT64_T(0, A1->GetId());
   CHECK_EQ_UINT64_T(A1->GetId(), A2->GetId());
   const v8::HeapGraphNode* B1 =
-      GetProperty(global1, v8::HeapGraphEdge::PROPERTY, "B");
+      GetProperty(global1, v8::HeapGraphEdge::kProperty, "B");
+  CHECK_NE(NULL, B1);
   const v8::HeapGraphNode* B2 =
-      GetProperty(global2, v8::HeapGraphEdge::PROPERTY, "B");
+      GetProperty(global2, v8::HeapGraphEdge::kProperty, "B");
+  CHECK_NE(NULL, B2);
   CHECK_NE_UINT64_T(0, B1->GetId());
   CHECK_EQ_UINT64_T(B1->GetId(), B2->GetId());
   const v8::HeapGraphNode* a1 =
-      GetProperty(global1, v8::HeapGraphEdge::PROPERTY, "a");
+      GetProperty(global1, v8::HeapGraphEdge::kProperty, "a");
+  CHECK_NE(NULL, a1);
   const v8::HeapGraphNode* a2 =
-      GetProperty(global2, v8::HeapGraphEdge::PROPERTY, "a");
+      GetProperty(global2, v8::HeapGraphEdge::kProperty, "a");
+  CHECK_NE(NULL, a2);
   CHECK_NE_UINT64_T(0, a1->GetId());
   CHECK_EQ_UINT64_T(a1->GetId(), a2->GetId());
   const v8::HeapGraphNode* b1 =
-      GetProperty(global1, v8::HeapGraphEdge::PROPERTY, "b");
+      GetProperty(global1, v8::HeapGraphEdge::kProperty, "b");
+  CHECK_NE(NULL, b1);
   const v8::HeapGraphNode* b2 =
-      GetProperty(global2, v8::HeapGraphEdge::PROPERTY, "b");
+      GetProperty(global2, v8::HeapGraphEdge::kProperty, "b");
+  CHECK_NE(NULL, b2);
   CHECK_NE_UINT64_T(0, b1->GetId());
   CHECK_EQ_UINT64_T(b1->GetId(), b2->GetId());
 }
@@ -717,15 +794,15 @@ TEST(HeapSnapshotsDiff) {
   for (int i = 0, count = additions_root->GetChildrenCount(); i < count; ++i) {
     const v8::HeapGraphEdge* prop = additions_root->GetChild(i);
     const v8::HeapGraphNode* node = prop->GetToNode();
-    if (node->GetType() == v8::HeapGraphNode::OBJECT) {
+    if (node->GetType() == v8::HeapGraphNode::kObject) {
       v8::String::AsciiValue node_name(node->GetName());
       if (strcmp(*node_name, "A") == 0) {
-        CHECK(IsNodeRetainedAs(node, v8::HeapGraphEdge::PROPERTY, "a"));
+        CHECK(IsNodeRetainedAs(node, v8::HeapGraphEdge::kProperty, "a"));
         CHECK(!found_A);
         found_A = true;
         s1_A_id = node->GetId();
       } else if (strcmp(*node_name, "B") == 0) {
-        CHECK(IsNodeRetainedAs(node, v8::HeapGraphEdge::PROPERTY, "b2"));
+        CHECK(IsNodeRetainedAs(node, v8::HeapGraphEdge::kProperty, "b2"));
         CHECK(!found_B);
         found_B = true;
       }
@@ -741,10 +818,10 @@ TEST(HeapSnapshotsDiff) {
   for (int i = 0, count = deletions_root->GetChildrenCount(); i < count; ++i) {
     const v8::HeapGraphEdge* prop = deletions_root->GetChild(i);
     const v8::HeapGraphNode* node = prop->GetToNode();
-    if (node->GetType() == v8::HeapGraphNode::OBJECT) {
+    if (node->GetType() == v8::HeapGraphNode::kObject) {
       v8::String::AsciiValue node_name(node->GetName());
       if (strcmp(*node_name, "A") == 0) {
-        CHECK(IsNodeRetainedAs(node, v8::HeapGraphEdge::PROPERTY, "a"));
+        CHECK(IsNodeRetainedAs(node, v8::HeapGraphEdge::kProperty, "a"));
         CHECK(!found_A_del);
         found_A_del = true;
         s2_A_id = node->GetId();