Current schema of calculation max_snapshot_js_object_id is not always correct.

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 1140 matching lines @@
   DeleteArray(raw_entries_);
 }
 
 
 void HeapSnapshot::Delete() {
   collection_->RemoveSnapshot(this);
   delete this;
 }
 
 
+void HeapSnapshot::RememberLastSnapshotJSObjectId() {

[mnaganov (inactive), 2012/03/29 12:12:17]

I think, the word 'Snapshot' in the method name is superfluous.

+  max_snapshot_js_object_id_ = collection_->max_snapshot_js_object_id();
+}
+
+
 void HeapSnapshot::AllocateEntries(int entries_count,
                                    int children_count,
                                    int retainers_count) {
   ASSERT(raw_entries_ == NULL);
   raw_entries_size_ =
       HeapEntry::EntriesSize(entries_count, children_count, retainers_count);
   raw_entries_ = NewArray<char>(raw_entries_size_);
 }
 
 
@@ skipping 46 matching lines @@
 
 
 HeapEntry* HeapSnapshot::AddEntry(HeapEntry::Type type,
                                   const char* name,
                                   SnapshotObjectId id,
                                   int size,
                                   int children_count,
                                   int retainers_count) {
   HeapEntry* entry = GetNextEntryToInit();
   entry->Init(this, type, name, id, size, children_count, retainers_count);
-
-  // Track only js objects. They have odd ids.
-  if (id % HeapObjectsMap::kObjectIdStep && id > max_snapshot_js_object_id_)
-    max_snapshot_js_object_id_ = id;
-
   return entry;
 }
 
 
 void HeapSnapshot::SetDominatorsToSelf() {
   for (int i = 0; i < entries_.length(); ++i) {
     HeapEntry* entry = entries_[i];
     if (entry->dominator() == NULL) entry->set_dominator(entry);
   }
 }
@@ skipping 1914 matching lines @@
 
 
 bool HeapSnapshotGenerator::FillReferences() {
   SnapshotFiller filler(snapshot_, &entries_);
   // IterateAndExtractReferences cannot set object names because
   // it makes call to JSObject::LocalLookupRealNamedProperty which
   // in turn may relocate objects in property maps thus changing the heap
   // layout and affecting retainer counts. This is not acceptable because
   // number of retainers must not change between count and fill passes.
   // To avoid this there's a separate postpass that set object names.
-  return v8_heap_explorer_.IterateAndExtractReferences(&filler)
+  bool result = v8_heap_explorer_.IterateAndExtractReferences(&filler)
       && dom_explorer_.IterateAndExtractReferences(&filler)
       && v8_heap_explorer_.IterateAndSetObjectNames(&filler);
+  snapshot_->RememberLastSnapshotJSObjectId();

[mnaganov (inactive), 2012/03/29 12:12:17]

I would place this call into GenerateSnapshot. Having it here, one needs to look
into GenerateSnapshot in order to understand, at what stage this happens.

+  return result;
 }
 
 
 void HeapSnapshotGenerator::FillReversePostorderIndexes(
     Vector<HeapEntry*>* entries) {
   snapshot_->ClearPaint();
   int current_entry = 0;
   List<HeapEntry*> nodes_to_visit;
   nodes_to_visit.Add(snapshot_->root());
   snapshot_->root()->paint();
@@ skipping 558 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