[heap] Use HashMap as scratchpad backing store

src/heap/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include "src/base/bits.h"
 #include "src/heap/spaces.h"
 
@@ skipping 493 matching lines @@
   }
 
  private:
   class CompactionTask;
   class EvacuateNewSpaceVisitor;
   class EvacuateOldSpaceVisitor;
   class EvacuateVisitorBase;
   class HeapObjectVisitor;
   class SweeperTask;
 
+  static const int kInitialLocalPretenuringFeedbackCapacity = 256;
+
   explicit MarkCompactCollector(Heap* heap);
 
   bool WillBeDeoptimized(Code* code);
   void EvictPopularEvacuationCandidate(Page* page);
   void ClearInvalidStoreAndSlotsBufferEntries();
 
   void StartSweeperThreads();
 
   void ComputeEvacuationHeuristics(int area_size,
                                    int* target_fragmentation_percent,
@@ skipping 165 matching lines @@
   //   After: Live objects are unmarked, non-live regions have been added to
   //          their space's free list. Active eden semispace is compacted by
   //          evacuation.
   //
 
   // If we are not compacting the heap, we simply sweep the spaces except
   // for the large object space, clearing mark bits and adding unmarked
   // regions to each space's free list.
   void SweepSpaces();
 
-  void EvacuateNewSpace();
+  void EvacuateNewSpacePrologue();
+
+  // Returns local pretenuring feedback.
+  HashMap* EvacuateNewSpaceInParallel();
 
   void AddEvacuationSlotsBufferSynchronized(
       SlotsBuffer* evacuation_slots_buffer);
 
   void EvacuatePages(CompactionSpaceCollection* compaction_spaces,
                      SlotsBuffer** evacuation_slots_buffer);
 
   void EvacuatePagesInParallel();
 
   // The number of parallel compaction tasks, including the main thread.
@@ skipping 55 matching lines @@
 
   Heap* heap_;
   base::VirtualMemory* marking_deque_memory_;
   size_t marking_deque_memory_committed_;
   MarkingDeque marking_deque_;
   CodeFlusher* code_flusher_;
   bool have_code_to_deoptimize_;
 
   List<Page*> evacuation_candidates_;
 
+  List<MemoryChunk*> newspace_evacuation_candidates_;
+
   // The evacuation_slots_buffers_ are used by the compaction threads.
   // When a compaction task finishes, it uses
   // AddEvacuationSlotsbufferSynchronized to adds its slots buffer to the
   // evacuation_slots_buffers_ list using the evacuation_slots_buffers_mutex_
   // lock.
   base::Mutex evacuation_slots_buffers_mutex_;
   List<SlotsBuffer*> evacuation_slots_buffers_;
 
   base::SmartPointer<FreeList> free_list_old_space_;
   base::SmartPointer<FreeList> free_list_code_space_;
@@ skipping 81 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_MARK_COMPACT_H_