Ignore slots buffer overflow when recording entries of the allocation sites scratchpad.

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 3636 matching lines @@
 
 void Heap::InitializeAllocationSitesScratchpad() {
   ASSERT(allocation_sites_scratchpad()->length() ==
          kAllocationSiteScratchpadSize);
   for (int i = 0; i < kAllocationSiteScratchpadSize; i++) {
     allocation_sites_scratchpad()->set_undefined(i);
   }
 }
 
 
-void Heap::AddAllocationSiteToScratchpad(AllocationSite* site) {
+void Heap::AddAllocationSiteToScratchpad(AllocationSite* site,
+                                         ScratchpadSlotMode mode) {
   if (allocation_sites_scratchpad_length_ < kAllocationSiteScratchpadSize) {
     // We cannot use the normal write-barrier because slots need to be
     // recorded with non-incremental marking as well. We have to explicitly
     // record the slot to take evacuation candidates into account.
     allocation_sites_scratchpad()->set(
         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);
+
+    if (mode == RECORD_SCRATCHPAD_SLOT) {
+      mark_compact_collector()->RecordSlot(

[Michael Starzinger, 2014/03/05 13:58:11]

Can we get a short comment explaining why IGNORE_OVERFLOW is needed here?

[Hannes Payer (out of office), 2014/03/05 14:02:06]

Done.

+          slot, slot, *slot, SlotsBuffer::IGNORE_OVERFLOW);
+    }
     allocation_sites_scratchpad_length_++;
   }
 }
 
 
 Map* Heap::MapForExternalArrayType(ExternalArrayType array_type) {
   return Map::cast(roots_[RootIndexForExternalArrayType(array_type)]);
 }
 
 
@@ skipping 4000 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