Simple non-incremental compaction by evacuation.

src/heap.h

 // 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 850 matching lines @@
   // Returns whether there is a chance that another major GC could
   // collect more garbage.
   bool CollectGarbage(AllocationSpace space, GarbageCollector collector);
 
   // Performs garbage collection operation.
   // Returns whether there is a chance that another major GC could
   // collect more garbage.
   inline bool CollectGarbage(AllocationSpace space);
 
   static const int kNoGCFlags = 0;
+  // TODO(gc) we are ignoring this flag
   static const int kForceCompactionMask = 1;
   static const int kMakeHeapIterableMask = 2;
 
   // Performs a full garbage collection.  If (flags & kForceCompactionMask) is
   // non-zero then force compaction.  If (flags & kMakeHeapIterableMask) is non-
   // zero, then the slower precise sweeper is used, which leaves the heap in a
   // state where we can iterate over the heap visiting all objects.
   void CollectAllGarbage(int flags);
 
   // Ensure that we have swept all spaces in such a way that we can iterate
@@ skipping 326 matching lines @@
   Map* MapForExternalArrayType(ExternalArrayType array_type);
   RootListIndex RootIndexForExternalArrayType(
       ExternalArrayType array_type);
 
   void RecordStats(HeapStats* stats, bool take_snapshot = false);
 
   // Copy block of memory from src to dst. Size of block should be aligned
   // by pointer size.
   static inline void CopyBlock(Address dst, Address src, int byte_size);
 
-  inline void CopyBlockToOldSpaceAndUpdateWriteBarrier(Address dst,
-                                                       Address src,
-                                                       int byte_size);
-
   // Optimized version of memmove for blocks with pointer size aligned sizes and
   // pointer size aligned addresses.
   static inline void MoveBlock(Address dst, Address src, int byte_size);
 
   // Check new space expansion criteria and expand semispaces if it was hit.
   void CheckNewSpaceExpansionCriteria();
 
   inline void IncrementYoungSurvivorsCounter(int survived) {
     young_survivors_after_last_gc_ = survived;
     survived_since_last_expansion_ += survived;
@@ skipping 15 matching lines @@
 
     if (PromotedSpaceSize() >= adjusted_allocation_limit) return true;
 
     return false;
   }
 
 
   void UpdateNewSpaceReferencesInExternalStringTable(
       ExternalStringTableUpdaterCallback updater_func);
 
+  void UpdateReferencesInExternalStringTable(
+      ExternalStringTableUpdaterCallback updater_func);
+
   void ProcessWeakReferences(WeakObjectRetainer* retainer);
 
   // Helper function that governs the promotion policy from new space to
   // old.  If the object's old address lies below the new space's age
   // mark or if we've already filled the bottom 1/16th of the to space,
   // we try to promote this object.
   inline bool ShouldBePromoted(Address old_address, int object_size);
 
   int MaxObjectSizeInNewSpace() { return kMaxObjectSizeInNewSpace; }
 
@@ skipping 95 matching lines @@
   OldSpace* old_data_space_;
   OldSpace* code_space_;
   MapSpace* map_space_;
   CellSpace* cell_space_;
   LargeObjectSpace* lo_space_;
   HeapState gc_state_;
 
   // Returns the amount of external memory registered since last global gc.
   int PromotedExternalMemorySize();
 
-  int mc_count_;  // how many mark-compact collections happened
   int ms_count_;  // how many mark-sweep collections happened
   unsigned int gc_count_;  // how many gc happened
 
   // Total length of the strings we failed to flatten since the last GC.
   int unflattened_strings_length_;
 
 #define ROOT_ACCESSOR(type, name, camel_name)                                  \
   inline void set_##name(type* value) {                                 \
     roots_[k##camel_name##RootIndex] = value;                                  \
   }
@@ skipping 163 matching lines @@
 
   Address DoScavenge(ObjectVisitor* scavenge_visitor, Address new_space_front);
   static void ScavengeStoreBufferCallback(Heap* heap,
                                           MemoryChunk* page,
                                           StoreBufferEvent event);
 
   // Performs a major collection in the whole heap.
   void MarkCompact(GCTracer* tracer);
 
   // Code to be run before and after mark-compact.
-  void MarkCompactPrologue(bool is_compacting);
+  void MarkCompactPrologue();
 
   // Completely clear the Instanceof cache (to stop it keeping objects alive
   // around a GC).
   inline void CompletelyClearInstanceofCache();
 
 #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
   // Record statistics before and after garbage collection.
   void ReportStatisticsBeforeGC();
   void ReportStatisticsAfterGC();
 #endif
@@ skipping 525 matching lines @@
 
   // Sets the collector.
   void set_collector(GarbageCollector collector) { collector_ = collector; }
 
   // Sets the GC count.
   void set_gc_count(unsigned int count) { gc_count_ = count; }
 
   // Sets the full GC count.
   void set_full_gc_count(int count) { full_gc_count_ = count; }
 
-  // Sets the flag that this is a compacting full GC.
-  void set_is_compacting() { is_compacting_ = true; }
-  bool is_compacting() const { return is_compacting_; }
-
-  // Increment and decrement the count of marked objects.
-  void increment_marked_count() { ++marked_count_; }
-  void decrement_marked_count() { --marked_count_; }
-
-  int marked_count() { return marked_count_; }
-
   void increment_promoted_objects_size(int object_size) {
     promoted_objects_size_ += object_size;
   }
 
  private:
   // Returns a string matching the collector.
   const char* CollectorString();
 
   // Returns size of object in heap (in MB).
   double SizeOfHeapObjects() {
     return (static_cast<double>(HEAP->SizeOfObjects())) / MB;
   }
 
   double start_time_;  // Timestamp set in the constructor.
   intptr_t start_size_;  // Size of objects in heap set in constructor.
   GarbageCollector collector_;  // Type of collector.
 
   // A count (including this one, eg, the first collection is 1) of the
   // number of garbage collections.
   unsigned int gc_count_;
 
   // A count (including this one) of the number of full garbage collections.
   int full_gc_count_;
 
-  // True if the current GC is a compacting full collection, false
-  // otherwise.
-  bool is_compacting_;
-
-  // On a full GC, a count of the number of marked objects.  Incremented
-  // when an object is marked and decremented when an object's mark bit is
-  // cleared.  Will be zero on a scavenge collection.
-  int marked_count_;
-
   // Amounts of time spent in different scopes during GC.
   double scopes_[Scope::kNumberOfScopes];
 
   // Total amount of space either wasted or contained in one of free lists
   // before the current GC.
   intptr_t in_free_list_or_wasted_before_gc_;
 
   // Difference between space used in the heap at the beginning of the current
   // collection and the end of the previous collection.
   intptr_t allocated_since_last_gc_;
@@ skipping 193 matching lines @@
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_