Make sure that allocation site scratchpad entries get recorded.

src/heap.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 3603 matching lines @@
   ASSERT(allocation_sites_scratchpad()->length() ==
          kAllocationSiteScratchpadSize);
   for (int i = 0; i < kAllocationSiteScratchpadSize; i++) {
     allocation_sites_scratchpad()->set_undefined(i);
   }
 }
 
 
 void Heap::AddAllocationSiteToScratchpad(AllocationSite* site) {
   if (allocation_sites_scratchpad_length_ < kAllocationSiteScratchpadSize) {
+    // Since the processing of the allocation sites scratchpad happens after
+    // evacuation, we have to explicitly record the slot to take evacuation
+    // candidates into account.

[Michael Starzinger, 2014/02/11 10:48:48]

Maybe make it explicit in the comment that "we cannot use the normal
write-barrier because slots need to be recorded with non-incremental marking as
well".

[Hannes Payer (out of office), 2014/02/11 10:52:20]

Done.

     allocation_sites_scratchpad()->set(
-        allocation_sites_scratchpad_length_, site);
+        allocation_sites_scratchpad_length_, site, SKIP_WRITE_BARRIER);
+    Object** slot = allocation_sites_scratchpad()->RawFieldOfElementAt(
+        allocation_sites_scratchpad_length_);
+    mark_compact_collector()->RecordSlot(slot, slot, *slot);
     allocation_sites_scratchpad_length_++;
   }
 }
 
 
 Map* Heap::MapForExternalArrayType(ExternalArrayType array_type) {
   return Map::cast(roots_[RootIndexForExternalArrayType(array_type)]);
 }
 
 
@@ skipping 4063 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal