[Heap profiler] Add construction stack trace to heap object

src/heap-snapshot-generator.cc

Index: src/heap-snapshot-generator.cc
diff --git a/src/heap-snapshot-generator.cc b/src/heap-snapshot-generator.cc
index 6714c42ca982d27dc1c29afbf859402e7e0e5133..aa28d07b98c75ec4bc2436466f22f6e5a7d67a68 100644
--- a/src/heap-snapshot-generator.cc
+++ b/src/heap-snapshot-generator.cc
@@ -73,14 +73,16 @@ HeapEntry::HeapEntry(HeapSnapshot* snapshot,
                      Type type,
                      const char* name,
                      SnapshotObjectId id,
-                     size_t self_size)
+                     size_t self_size,
+                     unsigned trace_node_id)
     : type_(type),
       children_count_(0),
       children_index_(-1),
       self_size_(self_size),
-      id_(id),
       snapshot_(snapshot),
-      name_(name) { }
+      name_(name),
+      id_(id),
+      trace_node_id_(trace_node_id) { }
 
 
 void HeapEntry::SetNamedReference(HeapGraphEdge::Type type,
@@ -189,7 +191,7 @@ template <size_t ptr_size> struct SnapshotSizeConstants;
 
 template <> struct SnapshotSizeConstants<4> {
   static const int kExpectedHeapGraphEdgeSize = 12;
-  static const int kExpectedHeapEntrySize = 24;
+  static const int kExpectedHeapEntrySize = 28;
 };
 
 template <> struct SnapshotSizeConstants<8> {
@@ -243,6 +245,7 @@ HeapEntry* HeapSnapshot::AddRootEntry() {
   HeapEntry* entry = AddEntry(HeapEntry::kSynthetic,
                               "",
                               HeapObjectsMap::kInternalRootObjectId,
+                              0,
                               0);
   root_index_ = entry->index();
   ASSERT(root_index_ == 0);
@@ -255,6 +258,7 @@ HeapEntry* HeapSnapshot::AddGcRootsEntry() {
   HeapEntry* entry = AddEntry(HeapEntry::kSynthetic,
                               "(GC roots)",
                               HeapObjectsMap::kGcRootsObjectId,
+                              0,
                               0);
   gc_roots_index_ = entry->index();
   return entry;
@@ -268,6 +272,7 @@ HeapEntry* HeapSnapshot::AddGcSubrootEntry(int tag) {
       HeapEntry::kSynthetic,
       VisitorSynchronization::kTagNames[tag],
       HeapObjectsMap::GetNthGcSubrootId(tag),
+      0,
       0);
   gc_subroot_indexes_[tag] = entry->index();
   return entry;
@@ -277,8 +282,9 @@ HeapEntry* HeapSnapshot::AddGcSubrootEntry(int tag) {
 HeapEntry* HeapSnapshot::AddEntry(HeapEntry::Type type,
                                   const char* name,
                                   SnapshotObjectId id,
-                                  size_t size) {
-  HeapEntry entry(this, type, name, id, size);
+                                  size_t size,
+                                  unsigned trace_node_id) {
+  HeapEntry entry(this, type, name, id, size, trace_node_id);
   entries_.Add(entry);
   return &entries_.last();
 }
@@ -390,10 +396,10 @@ HeapObjectsMap::HeapObjectsMap(Heap* heap)
 }
 
 
-void HeapObjectsMap::MoveObject(Address from, Address to, int object_size) {
+bool HeapObjectsMap::MoveObject(Address from, Address to, int object_size) {
   ASSERT(to != NULL);
   ASSERT(from != NULL);
-  if (from == to) return;
+  if (from == to) return false;
   void* from_value = entries_map_.Remove(from, ComputePointerHash(from));
   if (from_value == NULL) {
     // It may occur that some untracked object moves to an address X and there
@@ -434,6 +440,7 @@ void HeapObjectsMap::MoveObject(Address from, Address to, int object_size) {
     entries_.at(from_entry_info_index).size = object_size;
     to_entry->value = from_value;
   }
+  return from_value != NULL;
 }
 
 
@@ -910,7 +917,13 @@ HeapEntry* V8HeapExplorer::AddEntry(Address address,
                                     size_t size) {
   SnapshotObjectId object_id = heap_object_map_->FindOrAddEntry(
       address, static_cast<unsigned int>(size));
-  return snapshot_->AddEntry(type, name, object_id, size);
+  unsigned trace_node_id = 0;
+  if (AllocationTracker* allocation_tracker =
+      snapshot_->profiler()->allocation_tracker()) {
+    trace_node_id =
+        allocation_tracker->address_to_trace()->GetTraceNodeId(address);
+  }
+  return snapshot_->AddEntry(type, name, object_id, size, trace_node_id);
 }
 
 
@@ -2143,7 +2156,8 @@ HeapEntry* BasicHeapEntriesAllocator::AllocateEntry(HeapThing ptr) {
       entries_type_,
       name,
       heap_object_map_->GenerateId(info),
-      size != -1 ? static_cast<int>(size) : 0);
+      size != -1 ? static_cast<int>(size) : 0,
+      0);
 }
 
 
@@ -2642,8 +2656,8 @@ class OutputStreamWriter {
 
 // type, name|index, to_node.
 const int HeapSnapshotJSONSerializer::kEdgeFieldsCount = 3;
-// type, name, id, self_size, children_index.
-const int HeapSnapshotJSONSerializer::kNodeFieldsCount = 5;
+// type, name, id, self_size, edge_count, trace_node_id.
+const int HeapSnapshotJSONSerializer::kNodeFieldsCount = 6;
 
 void HeapSnapshotJSONSerializer::Serialize(v8::OutputStream* stream) {
   if (AllocationTracker* allocation_tracker =
@@ -2783,9 +2797,9 @@ void HeapSnapshotJSONSerializer::SerializeEdges() {
 void HeapSnapshotJSONSerializer::SerializeNode(HeapEntry* entry) {
   // The buffer needs space for 4 unsigned ints, 1 size_t, 5 commas, \n and \0
   static const int kBufferSize =
-      4 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned  // NOLINT
+      5 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned  // NOLINT
       + MaxDecimalDigitsIn<sizeof(size_t)>::kUnsigned  // NOLINT
-      + 5 + 1 + 1;
+      + 6 + 1 + 1;
   EmbeddedVector<char, kBufferSize> buffer;
   int buffer_pos = 0;
   if (entry_index(entry) != 0) {
@@ -2800,6 +2814,8 @@ void HeapSnapshotJSONSerializer::SerializeNode(HeapEntry* entry) {
   buffer_pos = utoa(entry->self_size(), buffer, buffer_pos);
   buffer[buffer_pos++] = ',';
   buffer_pos = utoa(entry->children_count(), buffer, buffer_pos);
+  buffer[buffer_pos++] = ',';
+  buffer_pos = utoa(entry->trace_node_id(), buffer, buffer_pos);
   buffer[buffer_pos++] = '\n';
   buffer[buffer_pos++] = '\0';
   writer_->AddString(buffer.start());
@@ -2833,7 +2849,8 @@ void HeapSnapshotJSONSerializer::SerializeSnapshot() {
         JSON_S("name") ","
         JSON_S("id") ","
         JSON_S("self_size") ","
-        JSON_S("edge_count")) ","
+        JSON_S("edge_count") ","
+        JSON_S("trace_node_id")) ","
     JSON_S("node_types") ":" JSON_A(
         JSON_A(
             JSON_S("hidden") ","