- Remember the fact that an object has been added to the

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 1242 matching lines @@
   explicit StoreBufferUpdateVisitor(Isolate* isolate, RawObject* obj) :
       ObjectPointerVisitor(isolate), old_obj_(obj) {
     ASSERT(old_obj_->IsOldObject());
   }
 
   void VisitPointers(RawObject** first, RawObject** last) {
     for (RawObject** curr = first; curr <= last; ++curr) {
       RawObject* raw_obj = *curr;
       if (raw_obj->IsHeapObject() && raw_obj->IsNewObject()) {
         uword ptr = reinterpret_cast<uword>(old_obj_);
+        old_obj_->SetRememberedBit();
         isolate()->store_buffer()->AddPointer(ptr);
         // Remembered this object. There is no need to continue searching.
         return;
       }
     }
   }
 
  private:
   RawObject* old_obj_;
 
@@ skipping 11 matching lines @@
 }
 
 
 
 RawObject* Object::Clone(const Object& src, Heap::Space space) {
   const Class& cls = Class::Handle(src.clazz());
   intptr_t size = src.raw()->Size();
   RawObject* raw_obj = Object::Allocate(cls.id(), size, space);
   NoGCScope no_gc;
   memmove(raw_obj->ptr(), src.raw()->ptr(), size);
-  if (space == Heap::kOld) {
+  if ((space == Heap::kOld) && !raw_obj->IsRemembered()) {
     StoreBufferUpdateVisitor visitor(Isolate::Current(), raw_obj);
     raw_obj->VisitPointers(&visitor);
   }
   return raw_obj;
 }
 
 
 RawString* Class::Name() const {
   ASSERT(raw_ptr()->name_ != String::null());
   return raw_ptr()->name_;
@@ skipping 11862 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "_WeakProperty";
 }
 
 }  // namespace dart