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

src/heap.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 7078 matching lines @@
  public:
   explicit MarkVisitor(PathTracer* tracer) : tracer_(tracer) {}
   void VisitPointers(Object** start, Object** end) {
     // Scan all HeapObject pointers in [start, end)
     for (Object** p = start; !tracer_->found() && (p < end); p++) {
       if ((*p)->IsHeapObject())
         tracer_->MarkRecursively(p, this);
     }
   }
 
+  WeakPointerMode weak_pointer_mode() {
+    return SKIP_WEAK_POINTERS;
+  }
+
  private:
   PathTracer* tracer_;
 };
 
 
 class PathTracer::UnmarkVisitor: public ObjectVisitor {
  public:
   explicit UnmarkVisitor(PathTracer* tracer) : tracer_(tracer) {}
   void VisitPointers(Object** start, Object** end) {
     // Scan all HeapObject pointers in [start, end)
     for (Object** p = start; p < end; p++) {
       if ((*p)->IsHeapObject())
         tracer_->UnmarkRecursively(p, this);
     }
   }
 
+  WeakPointerMode weak_pointer_mode() {
+    return SKIP_WEAK_POINTERS;
+  }
+
  private:
   PathTracer* tracer_;
 };
 
 
 void PathTracer::VisitPointers(Object** start, Object** end) {
   bool done = ((what_to_find_ == FIND_FIRST) && found_target_);
   // Visit all HeapObject pointers in [start, end)
   for (Object** p = start; !done && (p < end); p++) {
     if ((*p)->IsHeapObject()) {
@@ skipping 618 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal