Bookkeeping for allocation site pretenuring

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 627d371142e768a93ec1475e55bd08e185d395c6..2e60bb40944d95e10a02b919784c3f1c71f577e2 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -5714,10 +5714,7 @@ class JSObjectCopyVisitor: public JSObjectWalkVisitor {
     // 2) the elements kind is palatable
     // 3) allow_mementos is true
     Handle<JSObject> copy;
-    if (site_context()->activated() &&
-        AllocationSite::CanTrack(object->map()->instance_type()) &&
-        AllocationSite::GetMode(object->GetElementsKind()) ==
-        TRACK_ALLOCATION_SITE) {
+    if (site_context()->ShouldCreateMemento(object)) {
       copy = JSObject::Copy(object, site_context()->current());
     } else {
       copy = JSObject::Copy(object);
@@ -9233,7 +9230,9 @@ AllocationMemento* AllocationMemento::FindForJSObject(JSObject* object,
           object->GetHeap()->allocation_memento_map()) {
         AllocationMemento* memento = AllocationMemento::cast(
             reinterpret_cast<Object*>(ptr_end + kHeapObjectTag));
-        return memento;
+        if (memento->IsValid()) {
+          return memento;
+        }
       }
     }
   }