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

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 22083)
+++ runtime/vm/object.h	(working copy)
@@ -440,7 +440,9 @@
     *addr = value;
     // Filter stores based on source and target.
     if (!value->IsHeapObject()) return;
-    if (value->IsNewObject() && raw()->IsOldObject()) {
+    if (value->IsNewObject() && raw()->IsOldObject() &&
+        !raw()->IsRemembered()) {
+      raw()->SetRememberedBit();
       uword ptr = reinterpret_cast<uword>(raw());
       Isolate::Current()->store_buffer()->AddPointer(ptr);
     }
@@ -4963,7 +4965,9 @@
     *addr = value;
     // Filter stores based on source and target.
     if (!value->IsHeapObject()) return;
-    if (value->IsNewObject() && data()->IsOldObject()) {
+    if (value->IsNewObject() && data()->IsOldObject() &&
+        !data()->IsRemembered()) {
+      data()->SetRememberedBit();
       uword ptr = reinterpret_cast<uword>(data());
       Isolate::Current()->store_buffer()->AddPointer(ptr);
     }