Fix memory leak caused by treating Code::next_code_link as strong in marker.

src/mark-compact.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 88 matching lines @@
   }
 
   void VisitCell(RelocInfo* rinfo) {
     Code* code = rinfo->host();
     ASSERT(rinfo->rmode() == RelocInfo::CELL);
     if (!code->IsWeakObject(rinfo->target_cell())) {
       ObjectVisitor::VisitCell(rinfo);
     }
   }
 
+  WeakPointerMode weak_pointer_mode() {
+    return SKIP_WEAK_POINTERS;
+  }
+
  private:
   Heap* heap_;
 };
 
 
 static void VerifyMarking(Heap* heap, Address bottom, Address top) {
   VerifyMarkingVisitor visitor(heap);
   HeapObject* object;
   Address next_object_must_be_here_or_later = bottom;
 
@@ skipping 1734 matching lines @@
     : collector_(heap->mark_compact_collector()) { }
 
   void VisitPointer(Object** p) {
     MarkObjectByPointer(p);
   }
 
   void VisitPointers(Object** start, Object** end) {
     for (Object** p = start; p < end; p++) MarkObjectByPointer(p);
   }
 
+  WeakPointerMode weak_pointer_mode() {
+    return SKIP_WEAK_POINTERS;
+  }
+
  private:
   void MarkObjectByPointer(Object** p) {
     if (!(*p)->IsHeapObject()) return;
 
     // Replace flat cons strings in place.
     HeapObject* object = ShortCircuitConsString(p);
     MarkBit mark_bit = Marking::MarkBitFrom(object);
     if (mark_bit.Get()) return;
 
     Map* map = object->map();
@@ skipping 2604 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal