Add ObjectMoveEvent reporting for the Heap Profiler into MarkCompact.

src/profile-generator.cc

 // Copyright 2011 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 1380 matching lines @@
   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) {
     void* value = entry->value;
     entries_map_.Remove(from, AddressHash(from));
-    entry = entries_map_.Lookup(to, AddressHash(to), true);
-    // We can have an entry at the new location, it is OK, as GC can overwrite
-    // dead objects with alive objects being moved.
-    entry->value = value;
+    if (to != NULL) {
+      entry = entries_map_.Lookup(to, AddressHash(to), true);
+      // We can have an entry at the new location, it is OK, as GC can overwrite
+      // dead objects with alive objects being moved.
+      entry->value = value;
+    }
   }
 }
 
 
 void HeapObjectsMap::AddEntry(Address addr, uint64_t id) {
   HashMap::Entry* entry = entries_map_.Lookup(addr, AddressHash(addr), true);
   ASSERT(entry->value == NULL);
   entry->value = reinterpret_cast<void*>(entries_->length());
   entries_->Add(EntryInfo(id));
 }
@@ skipping 1953 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