Serialize edge counts instead of indexes in heap snapshot.

src/profile-generator.cc

 // Copyright 2012 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 3230 matching lines @@
       SnapshotSizeConstants<kPointerSize>::kMaxSerializableSnapshotRawSize / MB,
       (snapshot_->RawSnapshotSize() + MB - 1) / MB);
   HeapEntry* message = result->AddEntry(HeapEntry::kString, text, 0, 4);
   result->root()->SetIndexedReference(HeapGraphEdge::kElement, 1, message);
   result->FillChildren();
   return result;
 }
 
 
 void HeapSnapshotJSONSerializer::SerializeImpl() {
-  List<HeapEntry>& nodes = snapshot_->entries();
   ASSERT(0 == snapshot_->root()->index());
   writer_->AddCharacter('{');
   writer_->AddString("\"snapshot\":{");
   SerializeSnapshot();
   if (writer_->aborted()) return;
   writer_->AddString("},\n");
   writer_->AddString("\"nodes\":[");
-  SerializeNodes(nodes);
+  SerializeNodes();
   if (writer_->aborted()) return;
   writer_->AddString("],\n");
   writer_->AddString("\"edges\":[");
-  SerializeEdges(nodes);
+  SerializeEdges();
   if (writer_->aborted()) return;
   writer_->AddString("],\n");
   writer_->AddString("\"strings\":[");
   SerializeStrings();
   if (writer_->aborted()) return;
   writer_->AddCharacter(']');
   writer_->AddCharacter('}');
   writer_->Finalize();
 }
 
@@ skipping 21 matching lines @@
     int last_digit = value % 10;
     buffer[--buffer_pos] = '0' + last_digit;
     value /= 10;
   } while (value);
   return result;
 }
 
 
 void HeapSnapshotJSONSerializer::SerializeEdge(HeapGraphEdge* edge,
                                                bool first_edge) {
-  // The buffer needs space for 3 ints, 3 commas and \0
+  // The buffer needs space for 3 unsigned ints, 3 commas and \0
   static const int kBufferSize =
-      MaxDecimalDigitsIn<sizeof(int)>::kSigned * 3 + 3 + 1;  // NOLINT
+      MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned * 3 + 3 + 1;  // NOLINT
   EmbeddedVector<char, kBufferSize> buffer;
   int edge_name_or_index = edge->type() == HeapGraphEdge::kElement
       || edge->type() == HeapGraphEdge::kHidden
       || edge->type() == HeapGraphEdge::kWeak
       ? edge->index() : GetStringId(edge->name());
   int buffer_pos = 0;
   if (!first_edge) {
     buffer[buffer_pos++] = ',';
   }
   buffer_pos = utoa(edge->type(), buffer, buffer_pos);
   buffer[buffer_pos++] = ',';
   buffer_pos = utoa(edge_name_or_index, buffer, buffer_pos);
   buffer[buffer_pos++] = ',';
   buffer_pos = utoa(entry_index(edge->to()), buffer, buffer_pos);
   buffer[buffer_pos++] = '\0';
   writer_->AddString(buffer.start());
 }
 
 
-void HeapSnapshotJSONSerializer::SerializeEdges(const List<HeapEntry>& nodes) {
-  bool first_edge = true;
-  for (int i = 0; i < nodes.length(); ++i) {
-    HeapEntry* entry = &nodes[i];
-    Vector<HeapGraphEdge*> children = entry->children();
-    for (int j = 0; j < children.length(); ++j) {
-      SerializeEdge(children[j], first_edge);
-      first_edge = false;
-      if (writer_->aborted()) return;
-    }
+void HeapSnapshotJSONSerializer::SerializeEdges() {
+  List<HeapGraphEdge*>& edges = snapshot_->children();
+  for (int i = 0; i < edges.length(); ++i) {
+    ASSERT(i == 0 ||
+           edges[i - 1]->from()->index() <= edges[i]->from()->index());
+    SerializeEdge(edges[i], i == 0);
+    if (writer_->aborted()) return;
   }
 }
 
 
-void HeapSnapshotJSONSerializer::SerializeNode(HeapEntry* entry,
-                                               int edges_index) {
-  // The buffer needs space for 5 uint32_t, 5 commas, \n and \0
+void HeapSnapshotJSONSerializer::SerializeNode(HeapEntry* entry) {
+  // The buffer needs space for 5 unsigned ints, 5 commas, \n and \0
   static const int kBufferSize =
-      5 * MaxDecimalDigitsIn<sizeof(uint32_t)>::kUnsigned  // NOLINT
+      5 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned  // NOLINT
       + 5 + 1 + 1;
   EmbeddedVector<char, kBufferSize> buffer;
   int buffer_pos = 0;
   if (entry_index(entry) != 0) {
     buffer[buffer_pos++] = ',';
   }
   buffer_pos = utoa(entry->type(), buffer, buffer_pos);
   buffer[buffer_pos++] = ',';
   buffer_pos = utoa(GetStringId(entry->name()), buffer, buffer_pos);
   buffer[buffer_pos++] = ',';
   buffer_pos = utoa(entry->id(), buffer, buffer_pos);
   buffer[buffer_pos++] = ',';
   buffer_pos = utoa(entry->self_size(), buffer, buffer_pos);
   buffer[buffer_pos++] = ',';
-  buffer_pos = utoa(edges_index, buffer, buffer_pos);
+  buffer_pos = utoa(entry->children_count(), buffer, buffer_pos);
   buffer[buffer_pos++] = '\n';
   buffer[buffer_pos++] = '\0';
   writer_->AddString(buffer.start());
 }
 
 
-void HeapSnapshotJSONSerializer::SerializeNodes(const List<HeapEntry>& nodes) {
-  int edges_index = 0;
-  for (int i = 0; i < nodes.length(); ++i) {
-    HeapEntry* entry = &nodes[i];
-    SerializeNode(entry, edges_index);
-    edges_index += entry->children().length() * kEdgeFieldsCount;
+void HeapSnapshotJSONSerializer::SerializeNodes() {
+  List<HeapEntry>& entries = snapshot_->entries();
+  for (int i = 0; i < entries.length(); ++i) {
+    SerializeNode(&entries[i]);
     if (writer_->aborted()) return;
   }
 }
 
 
 void HeapSnapshotJSONSerializer::SerializeSnapshot() {
   writer_->AddString("\"title\":\"");
   writer_->AddString(snapshot_->title());
   writer_->AddString("\"");
   writer_->AddString(",\"uid\":");
   writer_->AddNumber(snapshot_->uid());
   writer_->AddString(",\"meta\":");
   // The 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("node_fields") ":" JSON_A(
         JSON_S("type") ","
         JSON_S("name") ","
         JSON_S("id") ","
         JSON_S("self_size") ","
-        JSON_S("edges_index")) ","
+        JSON_S("edge_count")) ","
     JSON_S("node_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") ","
@@ skipping 117 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