New heap profiler: implement fast retaining sizes approximation.

src/profile-generator.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 851 matching lines @@
 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;
+  retained_size_ = 0;
   children_count_ = children_count;
   retainers_count_ = retainers_count;
+  dominator_ = NULL;
 }
 
 
 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::SetIndexedReference(HeapGraphEdge::Type type,
                                     int child_index,
                                     int index,
                                     HeapEntry* entry,
                                     int retainer_index) {
   children_arr()[child_index].Init(child_index, type, index, entry);
   entry->retainers_arr()[retainer_index] = children_arr() + child_index;
 }
 
 
 void HeapEntry::SetUnidirElementReference(
     int child_index, int index, HeapEntry* entry) {
   children_arr()[child_index].Init(child_index, index, entry);
 }
 
 
-int HeapEntry::ReachableSize() {
-  if (calculated_data_index_ == kNoCalculatedData) {
-    calculated_data_index_ = snapshot_->AddCalculatedData();
+int HeapEntry::RetainedSize(bool exact) {
+  if (exact && (retained_size_ & kExactRetainedSizeTag) == 0) {
+    CalculateExactRetainedSize();
   }
-  return snapshot_->GetCalculatedData(
-      calculated_data_index_).ReachableSize(this);
-}
-
-
-int HeapEntry::RetainedSize() {
-  if (calculated_data_index_ == kNoCalculatedData) {
-    calculated_data_index_ = snapshot_->AddCalculatedData();
-  }
-  return snapshot_->GetCalculatedData(
-      calculated_data_index_).RetainedSize(this);
+  return retained_size_ & (~kExactRetainedSizeTag);
 }
 
 
 List<HeapGraphPath*>* HeapEntry::GetRetainingPaths() {
-  if (calculated_data_index_ == kNoCalculatedData) {
-    calculated_data_index_ = snapshot_->AddCalculatedData();
-  }
-  return snapshot_->GetCalculatedData(
-      calculated_data_index_).GetRetainingPaths(this);
+  return snapshot_->GetRetainingPaths(this);
 }
 
 
 template<class Visitor>
 void HeapEntry::ApplyAndPaintAllReachable(Visitor* visitor) {
   List<HeapEntry*> list(10);
   list.Add(this);
   this->paint_reachable();
   visitor->Apply(this);
   while (!list.is_empty()) {
@@ skipping 17 matching lines @@
   void Apply(HeapEntry* entry) { }
 };
 
 void HeapEntry::PaintAllReachable() {
   NullClass null;
   ApplyAndPaintAllReachable(&null);
 }
 
 
 void HeapEntry::Print(int max_depth, int indent) {
-  OS::Print("%6d %6d %6d [%llu] ",
-            self_size(), ReachableSize(), RetainedSize(), id_);
+  OS::Print("%6d %6d [%llu] ", self_size(), RetainedSize(false), 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");
@@ skipping 49 matching lines @@
 
 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
 }
 
 
-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:
-  ReachableSizeCalculator()
-      : reachable_size_(0) {
-  }
-
-  int reachable_size() const { return reachable_size_; }
-
-  void Apply(HeapEntry* entry) {
-    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 retained_size_;
 };
 
-void HeapEntryCalculatedData::CalculateSizes(HeapEntry* entry) {
+void HeapEntry::CalculateExactRetainedSize() {
   // 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();
+  // one color, then we paint (or re-paint) all nodes reachable from
+  // other nodes with a different color. Then we sum up self sizes of
+  // nodes painted with the first color.
+  snapshot()->ClearPaint();
+  PaintAllReachable();
 
   List<HeapEntry*> list(10);
-  HeapEntry* root = entry->snapshot()->root();
-  if (entry != root) {
+  HeapEntry* root = snapshot()->root();
+  if (this != root) {
     list.Add(root);
     root->paint_reachable_from_others();
   }
   while (!list.is_empty()) {
     HeapEntry* curr = list.RemoveLast();
     Vector<HeapGraphEdge> children = curr->children();
     for (int i = 0; i < children.length(); ++i) {
       if (children[i].type() == HeapGraphEdge::kShortcut) continue;
       HeapEntry* child = children[i].to();
-      if (child != entry && child->not_painted_reachable_from_others()) {
+      if (child != this && child->not_painted_reachable_from_others()) {
         list.Add(child);
         child->paint_reachable_from_others();
       }
     }
   }
 
   RetainedSizeCalculator ret_size_calc;
-  entry->snapshot()->IterateEntries(&ret_size_calc);
+  snapshot()->IterateEntries(&ret_size_calc);
   retained_size_ = ret_size_calc.reained_size();
+  ASSERT((retained_size_ & kExactRetainedSizeTag) == 0);
+  retained_size_ |= kExactRetainedSizeTag;
 }
 
 
 class CachedHeapGraphPath {
  public:
   CachedHeapGraphPath()
       : nodes_(NodesMatch) { }
   CachedHeapGraphPath(const CachedHeapGraphPath& src)
       : nodes_(NodesMatch, &HashMap::DefaultAllocator, src.nodes_.capacity()),
         path_(src.path_.length() + 1) {
@@ skipping 17 matching lines @@
   static uint32_t Hash(HeapEntry* entry) {
     return static_cast<uint32_t>(reinterpret_cast<intptr_t>(entry));
   }
   static bool NodesMatch(void* key1, void* key2) { return key1 == key2; }
 
   HashMap nodes_;
   List<HeapGraphEdge*> path_;
 };
 
 
-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(entry, &path);
-  }
-  return retaining_paths_;
+List<HeapGraphPath*>* HeapEntry::CalculateRetainingPaths() {
+  List<HeapGraphPath*>* retaining_paths = new List<HeapGraphPath*>(4);
+  CachedHeapGraphPath path;
+  FindRetainingPaths(&path, retaining_paths);
+  return retaining_paths;
 }
 
 
-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];
+void HeapEntry::FindRetainingPaths(CachedHeapGraphPath* prev_path,
+                                   List<HeapGraphPath*>* retaining_paths) {
+  Vector<HeapGraphEdge*> rets = retainers();
+  for (int i = 0; i < rets.length(); ++i) {
+    HeapGraphEdge* ret_edge = rets[i];
     if (prev_path->ContainsNode(ret_edge->From())) continue;
-    if (ret_edge->From() != entry->snapshot()->root()) {
+    if (ret_edge->From() != snapshot()->root()) {
       CachedHeapGraphPath path(*prev_path);
       path.Add(ret_edge);
-      FindRetainingPaths(ret_edge->From(), &path);
+      ret_edge->From()->FindRetainingPaths(&path, retaining_paths);
     } else {
       HeapGraphPath* ret_path = new HeapGraphPath(*prev_path->path());
       ret_path->Set(0, ret_edge);
-      retaining_paths_->Add(ret_path);
+      retaining_paths->Add(ret_path);
     }
   }
 }
 
 
 HeapGraphPath::HeapGraphPath(const List<HeapGraphEdge*>& path)
     : path_(path.length() + 1) {
   Add(NULL);
   for (int i = path.length() - 1; i >= 0; --i) {
     Add(path[i]);
@@ skipping 39 matching lines @@
 
 
 // It is very important to keep objects that form a heap snapshot
 // as small as possible.
 namespace {  // Avoid littering the global namespace.
 
 template <size_t ptr_size> struct SnapshotSizeConstants;
 
 template <> struct SnapshotSizeConstants<4> {
   static const int kExpectedHeapGraphEdgeSize = 12;
-  static const int kExpectedHeapEntrySize = 32;
+  static const int kExpectedHeapEntrySize = 36;
 };
 
 template <> struct SnapshotSizeConstants<8> {
   static const int kExpectedHeapGraphEdgeSize = 24;
-  static const int kExpectedHeapEntrySize = 40;
+  static const int kExpectedHeapEntrySize = 48;
 };
 
 }  // namespace
 
 HeapSnapshot::HeapSnapshot(HeapSnapshotsCollection* collection,
                            HeapSnapshot::Type type,
                            const char* title,
                            unsigned uid)
     : collection_(collection),
       type_(type),
       title_(title),
       uid_(uid),
       root_entry_(NULL),
       gc_roots_entry_(NULL),
       raw_entries_(NULL),
-      entries_sorted_(false) {
+      entries_sorted_(false),
+      retaining_paths_(HeapEntry::Match) {
   STATIC_ASSERT(
       sizeof(HeapGraphEdge) ==
       SnapshotSizeConstants<sizeof(void*)>::kExpectedHeapGraphEdgeSize);  // NOLINT
   STATIC_ASSERT(
       sizeof(HeapEntry) ==
       SnapshotSizeConstants<sizeof(void*)>::kExpectedHeapEntrySize);  // NOLINT
 }
 
 
-static void DisposeCalculatedData(HeapEntryCalculatedData* cdata) {
-  cdata->Dispose();
+static void DeleteHeapGraphPath(HeapGraphPath** path_ptr) {
+  delete *path_ptr;
 }
 
 HeapSnapshot::~HeapSnapshot() {
   DeleteArray(raw_entries_);
-  calculated_data_.Iterate(DisposeCalculatedData);
+  for (HashMap::Entry* p = retaining_paths_.Start();
+       p != NULL;
+       p = retaining_paths_.Next(p)) {
+    List<HeapGraphPath*>* list =
+        reinterpret_cast<List<HeapGraphPath*>*>(p->value);
+    list->Iterate(DeleteHeapGraphPath);
+    delete list;
+  }
 }
 
 
 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));
 #ifdef DEBUG
@@ skipping 95 matching lines @@
 
 static void HeapEntryClearPaint(HeapEntry** entry_ptr) {
   (*entry_ptr)->clear_paint();
 }
 
 void HeapSnapshot::ClearPaint() {
   entries_.Iterate(HeapEntryClearPaint);
 }
 
 
-int HeapSnapshot::AddCalculatedData() {
-  calculated_data_.Add(HeapEntryCalculatedData());
-  return calculated_data_.length() - 1;
-}
-
-
 HeapEntry* HeapSnapshot::AddEntry(HeapObject* object,
                                   HeapEntry::Type type,
                                   const char* name,
                                   int children_count,
                                   int retainers_count) {
   return AddEntry(type,
                   name,
                   collection_->GetObjectId(object->address()),
                   object->Size(),
                   children_count,
                   retainers_count);
 }
 
 
 HeapEntry* HeapSnapshot::AddEntry(HeapEntry::Type type,
                                   const char* name,
                                   uint64_t id,
                                   int size,
                                   int children_count,
                                   int retainers_count) {
   HeapEntry* entry = GetNextEntryToInit();
   entry->Init(this, type, name, id, size, children_count, retainers_count);
   return entry;
 }
 
 
+void HeapSnapshot::FillReversePostorderIndexes(Vector<HeapEntry*>* entries) {
+  ClearPaint();
+  int current_entry = 0;
+  List<HeapEntry*> nodes_to_visit;
+  nodes_to_visit.Add(root());
+  root()->paint_reachable();
+  while (!nodes_to_visit.is_empty()) {
+    HeapEntry* entry = nodes_to_visit.last();
+    Vector<HeapGraphEdge> children = entry->children();
+    bool has_new_edges = false;
+    for (int i = 0; i < children.length(); ++i) {
+      if (children[i].type() == HeapGraphEdge::kShortcut) continue;
+      HeapEntry* child = children[i].to();
+      if (!child->painted_reachable()) {
+        nodes_to_visit.Add(child);
+        child->paint_reachable();
+        has_new_edges = true;
+      }
+    }
+    if (!has_new_edges) {
+      entry->set_ordered_index(current_entry);
+      entries->at(current_entry++) = entry;
+      nodes_to_visit.RemoveLast();
+    }
+  }
+  entries->Truncate(current_entry);
+}
+
+
+static int Intersect(int i1, int i2, const Vector<HeapEntry*>& dominators) {
+  int finger1 = i1, finger2 = i2;
+  while (finger1 != finger2) {
+    while (finger1 < finger2) finger1 = dominators[finger1]->ordered_index();
+    while (finger2 < finger1) finger2 = dominators[finger2]->ordered_index();
+  }
+  return finger1;
+}
+
+// The algorithm is based on the article:
+// K. Cooper, T. Harvey and K. Kennedy "A Simple, Fast Dominance Algorithm"
+// Softw. Pract. Exper. 4 (2001), pp. 1–10.
+void HeapSnapshot::BuildDominatorTree(const Vector<HeapEntry*>& entries,
+                                      Vector<HeapEntry*>* dominators) {
+  if (entries.length() == 0) return;
+  const int root_index = entries.length() - 1;
+  for (int i = 0; i < root_index; ++i) dominators->at(i) = NULL;
+  dominators->at(root_index) = entries[root_index];
+  bool changed = true;
+  while (changed) {
+    changed = false;
+    for (int i = root_index - 1; i >= 0; --i) {
+      HeapEntry* new_idom = NULL;
+      Vector<HeapGraphEdge*> rets = entries[i]->retainers();
+      int j = 0;
+      for (; j < rets.length(); ++j) {
+        if (rets[j]->type() == HeapGraphEdge::kShortcut) continue;
+        HeapEntry* ret = rets[j]->From();
+        if (dominators->at(ret->ordered_index()) != NULL) {
+          new_idom = ret;
+          break;
+        }
+      }
+      for (++j; j < rets.length(); ++j) {
+        if (rets[j]->type() == HeapGraphEdge::kShortcut) continue;
+        HeapEntry* ret = rets[j]->From();
+        if (dominators->at(ret->ordered_index()) != NULL) {
+          new_idom = entries[Intersect(ret->ordered_index(),
+                                       new_idom->ordered_index(),
+                                       *dominators)];
+        }
+      }
+      if (new_idom != NULL && dominators->at(i) != new_idom) {
+        dominators->at(i) = new_idom;
+        changed = true;
+      }
+    }
+  }
+}
+
+
+void HeapSnapshot::SetEntriesDominators() {
+  // This array is used for maintaining reverse postorder of nodes.
+  ScopedVector<HeapEntry*> ordered_entries(entries_.length());
+  FillReversePostorderIndexes(&ordered_entries);
+  ScopedVector<HeapEntry*> dominators(ordered_entries.length());
+  BuildDominatorTree(ordered_entries, &dominators);
+  for (int i = 0; i < ordered_entries.length(); ++i) {
+    ASSERT(dominators[i] != NULL);
+    ordered_entries[i]->set_dominator(dominators[i]);
+  }
+  // For nodes unreachable from root, set dominator to itself.
+  for (int i = 0; i < entries_.length(); ++i) {
+    HeapEntry* entry = entries_[i];
+    if (entry->dominator() == NULL) entry->set_dominator(entry);
+  }
+}
+
+
+void HeapSnapshot::ApproximateRetainedSizes() {
+  SetEntriesDominators();
+  // As for the dominators tree we only know parent nodes, not
+  // children, to sum up total sizes we traverse the tree level by
+  // level upwards, starting from leaves.
+  for (int i = 0; i < entries_.length(); ++i) {
+    HeapEntry* entry = entries_[i];
+    entry->set_retained_size(entry->self_size());
+    entry->set_leaf();
+  }
+  while (true) {
+    bool onlyLeaves = true;
+    for (int i = 0; i < entries_.length(); ++i) {
+      HeapEntry *entry = entries_[i], *dominator = entry->dominator();
+      if (!entry->is_processed() && dominator != entry) {
+        dominator->set_non_leaf();
+        onlyLeaves = false;
+      }
+    }
+    if (onlyLeaves) break;
+
+    for (int i = 0; i < entries_.length(); ++i) {
+      HeapEntry *entry = entries_[i], *dominator = entry->dominator();
+      if (entry->is_leaf() && dominator != entry) {
+        dominator->add_retained_size(entry->retained_size());
+      }
+    }
+
+    // Mark all current leaves as processed, reset non-leaves back to leaves.
+    for (int i = 0; i < entries_.length(); ++i) {
+      HeapEntry* entry = entries_[i];
+      if (entry->is_leaf())
+        entry->set_processed();
+      else if (entry->is_non_leaf())
+        entry->set_leaf();
+    }
+  }
+}
+
+
 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_));
   }
   ASSERT(reinterpret_cast<char*>(entries_.last()) <
          (raw_entries_ + raw_entries_size_));
   return entries_.last();
 }
 
 
 HeapSnapshotsDiff* HeapSnapshot::CompareWith(HeapSnapshot* snapshot) {
   return collection_->CompareSnapshots(this, snapshot);
 }
 
 
+List<HeapGraphPath*>* HeapSnapshot::GetRetainingPaths(HeapEntry* entry) {
+  HashMap::Entry* p =
+      retaining_paths_.Lookup(entry, HeapEntry::Hash(entry), true);
+  if (p->value == NULL) {
+    p->value = entry->CalculateRetainingPaths();
+  }
+  return reinterpret_cast<List<HeapGraphPath*>*>(p->value);
+}
+
+
 template<class T>
 static int SortByIds(const T* entry1_ptr,
                      const T* entry2_ptr) {
   if ((*entry1_ptr)->id() == (*entry2_ptr)->id()) return 0;
   return (*entry1_ptr)->id() < (*entry2_ptr)->id() ? -1 : 1;
 }
 
 List<HeapEntry*>* HeapSnapshot::GetSortedEntriesList() {
   if (!entries_sorted_) {
     entries_.Sort(SortByIds);
@@ skipping 425 matching lines @@
 
   // Pass 2. Fill references.
   SnapshotFiller filler(snapshot_, &entries_);
   filler_ = &filler;
   iterator.reset();
   for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     ExtractReferences(obj);
   }
   SetRootGcRootsReference();
   Heap::IterateRoots(&extractor, VISIT_ONLY_STRONG);
+
+  snapshot_->ApproximateRetainedSizes();
 }
 
 
 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) entry = filler_->AddEntry(object);
   return entry;
@@ skipping 555 matching lines @@
 void HeapSnapshotJSONSerializer::SerializeNode(HeapEntry* entry) {
   writer_->AddCharacter('\n');
   writer_->AddCharacter(',');
   writer_->AddNumber(entry->type());
   writer_->AddCharacter(',');
   writer_->AddNumber(GetStringId(entry->name()));
   writer_->AddCharacter(',');
   writer_->AddNumber(entry->id());
   writer_->AddCharacter(',');
   writer_->AddNumber(entry->self_size());
+  writer_->AddCharacter(',');
+  writer_->AddNumber(entry->RetainedSize(false));
+  writer_->AddCharacter(',');
+  writer_->AddNumber(GetNodeId(entry->dominator()));
   Vector<HeapGraphEdge> children = entry->children();
   writer_->AddCharacter(',');
   writer_->AddNumber(children.length());
   for (int i = 0; i < children.length(); ++i) {
     SerializeEdge(&children[i]);
     if (writer_->aborted()) return;
   }
 }
 
 
 void HeapSnapshotJSONSerializer::SerializeNodes() {
   // The first (zero) item of nodes array is an object describing node
   // serialization layout.  We use a set of macros to improve
   // readability.
 #define JSON_A(s) "["s"]"
 #define JSON_O(s) "{"s"}"
 #define JSON_S(s) "\""s"\""
   writer_->AddString(JSON_O(
     JSON_S("fields") ":" JSON_A(
         JSON_S("type")
         "," JSON_S("name")
         "," JSON_S("id")
         "," JSON_S("self_size")
+        "," JSON_S("retained_size")
+        "," JSON_S("dominator")
         "," JSON_S("children_count")
         "," JSON_S("children"))
     "," JSON_S("types") ":" JSON_A(
         JSON_A(
             JSON_S("hidden")
             "," JSON_S("array")
             "," JSON_S("string")
             "," JSON_S("object")
             "," JSON_S("code")
             "," JSON_S("closure")
             "," JSON_S("regexp")
             "," JSON_S("number"))
         "," JSON_S("string")
         "," JSON_S("number")
         "," JSON_S("number")
         "," JSON_S("number")
+        "," JSON_S("number")
+        "," JSON_S("number")
         "," JSON_O(
             JSON_S("fields") ":" JSON_A(
                 JSON_S("type")
                 "," JSON_S("name_or_index")
                 "," JSON_S("to_node"))
             "," JSON_S("types") ":" JSON_A(
                 JSON_A(
                     JSON_S("context")
                     "," JSON_S("element")
                     "," JSON_S("property")
                     "," JSON_S("internal")
                     "," JSON_S("hidden")
                     "," JSON_S("shortcut"))
                 "," JSON_S("string_or_number")
                 "," JSON_S("node"))))));
 #undef JSON_S
 #undef JSON_O
 #undef JSON_A
 
-  const int node_fields_count = 5;  // type,name,id,self_size,children_count.
+  const int node_fields_count = 7;
+  // type,name,id,self_size,retained_size,dominator,children_count.
   const int edge_fields_count = 3;  // type,name|index,to_node.
   List<HashMap::Entry*> sorted_nodes;
   SortHashMap(&nodes_, &sorted_nodes);
   // Rewrite node ids, so they refer to actual array positions.
   if (sorted_nodes.length() > 1) {
     // Nodes start from array index 1.
     int prev_value = 1;
     sorted_nodes[0]->value = reinterpret_cast<void*>(prev_value);
     for (int i = 1; i < sorted_nodes.length(); ++i) {
       HeapEntry* prev_heap_entry =
@@ skipping 108 matching lines @@
 void HeapSnapshotJSONSerializer::SortHashMap(
     HashMap* map, List<HashMap::Entry*>* sorted_entries) {
   for (HashMap::Entry* p = map->Start(); p != NULL; p = map->Next(p))
     sorted_entries->Add(p);
   sorted_entries->Sort(SortUsingEntryValue);
 }
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_LOGGING_AND_PROFILING