I'd like to add HeapSnapshot::GetMaxSnapshotJSObjectId function.

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 1115 matching lines @@
                            const char* title,
                            unsigned uid)
     : collection_(collection),
       type_(type),
       title_(title),
       uid_(uid),
       root_entry_(NULL),
       gc_roots_entry_(NULL),
       natives_root_entry_(NULL),
       raw_entries_(NULL),
-      entries_sorted_(false) {
+      entries_sorted_(false),
+      max_snapshot_js_object_id_(0) {
   STATIC_CHECK(
       sizeof(HeapGraphEdge) ==
       SnapshotSizeConstants<kPointerSize>::kExpectedHeapGraphEdgeSize);
   STATIC_CHECK(
       sizeof(HeapEntry) ==
       SnapshotSizeConstants<kPointerSize>::kExpectedHeapEntrySize);
   for (int i = 0; i < VisitorSynchronization::kNumberOfSyncTags; ++i) {
     gc_subroot_entries_[i] = NULL;
   }
 }
@@ skipping 69 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 has odd ids.

[yurys, 2012/03/26 14:53:20]

typo: has -> have

+  if (id % 2 && 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 84 matching lines @@
   RemoveDeadEntries();
 }
 
 
 SnapshotObjectId HeapObjectsMap::FindObject(Address addr) {
   if (!initial_fill_mode_) {
     SnapshotObjectId existing = FindEntry(addr);
     if (existing != 0) return existing;
   }
   SnapshotObjectId id = next_id_;
+  printf("newId = %d\n", next_id_);

[yurys, 2012/03/26 14:53:20]

Remove this.

   next_id_ += kObjectIdStep;
   AddEntry(addr, id);
   return id;
 }
 
 
 void HeapObjectsMap::MoveObject(Address from, Address to) {
   if (from == to) return;
   HashMap::Entry* entry = entries_map_.Lookup(from, AddressHash(from), false);
   if (entry != NULL) {
@@ skipping 2391 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