Symbols for type cells.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 15d9b3750ed4127ec95a8a6e49ec8c4f141169ca..7c8d15085add49516c1c339b457ee31dbb1e0ceb 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -6544,12 +6544,12 @@ MaybeObject* ConstantPoolArray::Copy() {
 
 
 Handle<Object> TypeFeedbackInfo::UninitializedSentinel(Isolate* isolate) {
-  return isolate->factory()->the_hole_value();
+  return isolate->factory()->uninitialized_symbol();
 }
 
 
 Handle<Object> TypeFeedbackInfo::MegamorphicSentinel(Isolate* isolate) {
-  return isolate->factory()->undefined_value();
+  return isolate->factory()->megamorphic_symbol();
 }
 
 
@@ -6560,7 +6560,7 @@ Handle<Object> TypeFeedbackInfo::MonomorphicArraySentinel(Isolate* isolate,
 
 
 Object* TypeFeedbackInfo::RawUninitializedSentinel(Heap* heap) {
-  return heap->the_hole_value();
+  return heap->uninitialized_symbol();
 }