Implement map collection for incremental marking.

src/mark-compact.h

 // 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 24 matching lines @@
 namespace internal {
 
 // Callback function, returns whether an object is alive. The heap size
 // of the object is returned in size. It optionally updates the offset
 // to the first live object in the page (only used for old and map objects).
 typedef bool (*IsAliveFunction)(HeapObject* obj, int* size, int* offset);
 
 // Forward declarations.
 class CodeFlusher;
 class GCTracer;
+class MarkCompactCollector;
 class MarkingVisitor;
 class RootMarkingVisitor;
 
 
 class Marking {
  public:
   explicit Marking(Heap* heap)
       : heap_(heap) {
   }
 
@@ skipping 104 matching lines @@
     }
     return is_black;
   }
 
  private:
   Heap* heap_;
 };
 
 // ----------------------------------------------------------------------------
 // Marking deque for tracing live objects.
-
 class MarkingDeque {
  public:
   MarkingDeque()
       : array_(NULL), top_(0), bottom_(0), mask_(0), overflowed_(false) { }
 
   void Initialize(Address low, Address high) {
     HeapObject** obj_low = reinterpret_cast<HeapObject**>(low);
     HeapObject** obj_high = reinterpret_cast<HeapObject**>(high);
     array_ = obj_low;
     mask_ = RoundDownToPowerOf2(static_cast<int>(obj_high - obj_low)) - 1;
@@ skipping 196 matching lines @@
  private:
   static const int kChainLengthThreshold = 15;
 
   intptr_t idx_;
   intptr_t chain_length_;
   SlotsBuffer* next_;
   ObjectSlot slots_[kNumberOfElements];
 };
 
 
+// -------------------------------------------------------------------------
+// Marker shared between incremental and non-incremental marking
+template<class BaseMarker> class Marker {
+ public:
+  Marker(BaseMarker* base_marker, MarkCompactCollector* mark_compact_collector)
+      : base_marker_(base_marker),
+        mark_compact_collector_(mark_compact_collector) {}
+
+  // Mark pointers in a Map and its DescriptorArray together, possibly
+  // treating transitions or back pointers weak.
+  void MarkMapContents(Map* map);
+  void MarkDescriptorArray(DescriptorArray* descriptors);
+  void MarkAccessorPairSlot(AccessorPair* accessors, int offset);
+
+ private:
+  BaseMarker* base_marker() {
+    return base_marker_;
+  }
+
+  MarkCompactCollector* mark_compact_collector() {
+    return mark_compact_collector_;
+  }
+
+  BaseMarker* base_marker_;
+  MarkCompactCollector* mark_compact_collector_;
+};
+
+
 // Defined in isolate.h.
 class ThreadLocalTop;
 
 
 // -------------------------------------------------------------------------
 // Mark-Compact collector
 class MarkCompactCollector {
  public:
   // Type of functions to compute forwarding addresses of objects in
   // compacted spaces.  Given an object and its size, return a (non-failure)
@@ skipping 181 matching lines @@
   bool reduce_memory_footprint_;
 
   bool abort_incremental_marking_;
 
   // True if we are collecting slots to perform evacuation from evacuation
   // candidates.
   bool compacting_;
 
   bool was_marked_incrementally_;
 
-  bool collect_maps_;
-
   bool flush_monomorphic_ics_;
 
   // A pointer to the current stack-allocated GC tracer object during a full
   // collection (NULL before and after).
   GCTracer* tracer_;
 
   SlotsBufferAllocator slots_buffer_allocator_;
 
   SlotsBuffer* migration_slots_buffer_;
 
   // 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.
   //
   //   After: Live objects are marked and non-live objects are unmarked.
 
-
   friend class RootMarkingVisitor;
   friend class MarkingVisitor;
   friend class StaticMarkingVisitor;
   friend class CodeMarkingVisitor;
   friend class SharedFunctionInfoMarkingVisitor;
+  friend class Marker<IncrementalMarking>;
+  friend class Marker<MarkCompactCollector>;
 
   // Mark non-optimize code for functions inlined into the given optimized
   // code. This will prevent it from being flushed.
   void MarkInlinedFunctionsCode(Code* code);
 
   // Mark code objects that are active on the stack to prevent them
   // from being flushed.
   void PrepareThreadForCodeFlushing(Isolate* isolate, ThreadLocalTop* top);
 
   void PrepareForCodeFlushing();
 
   // Marking operations for objects reachable from roots.
   void MarkLiveObjects();
 
   void AfterMarking();
 
   // Marks the object black and pushes it on the marking stack.
-  // This is for non-incremental marking.
+  // Returns true if object needed marking and false otherwise.
+  // This is for non-incremental marking only.
+  INLINE(bool MarkObjectAndPush(HeapObject* obj));
+
+  // Marks the object black and pushes it on the marking stack.
+  // This is for non-incremental marking only.
   INLINE(void MarkObject(HeapObject* obj, MarkBit mark_bit));
 
-  INLINE(bool MarkObjectWithoutPush(HeapObject* object));
-  INLINE(void MarkObjectAndPush(HeapObject* value));
+  // Marks the object black without pushing it on the marking stack.
+  // Returns true if object needed marking and false otherwise.
+  // This is for non-incremental marking only.
+  INLINE(bool MarkObjectWithoutPush(HeapObject* obj));
 
-  // Marks the object black.  This is for non-incremental marking.
+  // Marks the object black assuming that it is not yet marked.
+  // This is for non-incremental marking only.
   INLINE(void SetMark(HeapObject* obj, MarkBit mark_bit));
 
   void ProcessNewlyMarkedObject(HeapObject* obj);
 
-  // Mark a Map and its DescriptorArray together, skipping transitions.
-  void MarkMapContents(Map* map);
-  void MarkAccessorPairSlot(HeapObject* accessors, int offset);
-  void MarkDescriptorArray(DescriptorArray* descriptors);
-
   // Mark the heap roots and all objects reachable from them.
   void MarkRoots(RootMarkingVisitor* visitor);
 
   // Mark the symbol table specially.  References to symbols from the
   // symbol table are weak.
   void MarkSymbolTable();
 
   // Mark objects in object groups that have at least one object in the
   // group marked.
   void MarkObjectGroups();
@@ skipping 82 matching lines @@
   static void VisitObject(HeapObject* obj);
 
   friend class UnmarkObjectVisitor;
   static void UnmarkObject(HeapObject* obj);
 #endif
 
   Heap* heap_;
   MarkingDeque marking_deque_;
   CodeFlusher* code_flusher_;
   Object* encountered_weak_maps_;
+  Marker<MarkCompactCollector> marker_;
 
   List<Page*> evacuation_candidates_;
   List<Code*> invalidated_code_;
 
   friend class Heap;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_