Synchronize on concurrent slot buffer entries during migration.

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 356 matching lines @@
       buffer = buffer->next();
     }
   }
 
   enum AdditionMode { FAIL_ON_OVERFLOW, IGNORE_OVERFLOW };
 
   static bool ChainLengthThresholdReached(SlotsBuffer* buffer) {
     return buffer != NULL && buffer->chain_length_ >= kChainLengthThreshold;
   }
 
+  INLINE(static bool AddToSynchronized(SlotsBufferAllocator* allocator,
+                                       SlotsBuffer** buffer_address,
+                                       base::Mutex* buffer_mutex,
+                                       ObjectSlot slot, AdditionMode mode)) {
+    base::LockGuard<base::Mutex> lock_guard(buffer_mutex);
+    return AddTo(allocator, buffer_address, slot, mode);
+  }
+
   INLINE(static bool AddTo(SlotsBufferAllocator* allocator,
                            SlotsBuffer** buffer_address, ObjectSlot slot,
                            AdditionMode mode)) {
     SlotsBuffer* buffer = *buffer_address;
     if (buffer == NULL || buffer->IsFull()) {
       if (mode == FAIL_ON_OVERFLOW && ChainLengthThresholdReached(buffer)) {
         allocator->DeallocateChain(buffer_address);
         return false;
       }
       buffer = allocator->AllocateBuffer(buffer);
       *buffer_address = buffer;
     }
     buffer->Add(slot);
     return true;
   }
 
   static bool IsTypedSlot(ObjectSlot slot);
 
+  static bool AddToSynchronized(SlotsBufferAllocator* allocator,
+                                SlotsBuffer** buffer_address,
+                                base::Mutex* buffer_mutex, SlotType type,
+                                Address addr, AdditionMode mode);
+
   static bool AddTo(SlotsBufferAllocator* allocator,
                     SlotsBuffer** buffer_address, SlotType type, Address addr,
                     AdditionMode mode);
 
   // Eliminates all stale entries from the slots buffer, i.e., slots that
   // are not part of live objects anymore. This method must be called after
   // marking, when the whole transitive closure is known and must be called
   // before sweeping when mark bits are still intact.
   static void RemoveInvalidSlots(Heap* heap, SlotsBuffer* buffer);
 
@@ skipping 310 matching lines @@
 
   // Synchronize compaction threads.
   base::Semaphore pending_compaction_jobs_semaphore_;
 
   bool evacuation_;
 
   SlotsBufferAllocator slots_buffer_allocator_;
 
   SlotsBuffer* migration_slots_buffer_;
 
+  base::Mutex migration_slots_buffer_mutex_;
+
   // Finishes GC, performs heap verification if enabled.
   void Finish();
 
   // -----------------------------------------------------------------------
   // Phase 1: Marking live objects.
   //
   //  Before: The heap has been prepared for garbage collection by
   //          MarkCompactCollector::Prepare() and is otherwise in its
   //          normal state.
   //
@@ skipping 155 matching lines @@
 
   // Finalizes the parallel sweeping phase. Marks all the pages that were
   // swept in parallel.
   void ParallelSweepSpacesComplete();
 
   void ParallelSweepSpaceComplete(PagedSpace* space);
 
   // Updates store buffer and slot buffer for a pointer in a migrating object.
   void RecordMigratedSlot(Object* value, Address slot);
 
+  // Adds the code entry slot to the slots buffer.
+  void RecordMigratedCodeEntrySlot(Address code_entry, Address code_entry_slot);
+
+  // Adds the slot of a moved code object.
+  void RecordMigratedCodeObjectSlot(Address code_object);
+
 #ifdef DEBUG
   friend class MarkObjectVisitor;
   static void VisitObject(HeapObject* obj);
 
   friend class UnmarkObjectVisitor;
   static void UnmarkObject(HeapObject* obj);
 #endif
 
   Heap* heap_;
   base::VirtualMemory* marking_deque_memory_;
@@ skipping 65 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_MARK_COMPACT_H_