Symbols for type cells.

src/a64/builtins-a64.cc

Index: src/a64/builtins-a64.cc
diff --git a/src/a64/builtins-a64.cc b/src/a64/builtins-a64.cc
index 797fbc3a5421eb9f1dd4f1250efe136eca4d4f05..be700095acc24bda2be12f4a28103332ca8e871a 100644
--- a/src/a64/builtins-a64.cc
+++ b/src/a64/builtins-a64.cc
@@ -149,10 +149,9 @@ void Builtins::Generate_ArrayCode(MacroAssembler* masm) {
   }
 
   // Run the native code for the Array function called as a normal function.
-  Handle<Object> undefined_sentinel(
-      masm->isolate()->heap()->undefined_value(),
-      masm->isolate());
-  __ Mov(x2, Operand(undefined_sentinel));
+  Handle<Object> megamorphic_sentinel =
+      TypeFeedbackInfo::MegamorphicSentinel(masm->isolate());
+  __ Mov(x2, Operand(megamorphic_sentinel));
   ArrayConstructorStub stub(masm->isolate());
   __ TailCallStub(&stub);
 }
@@ -715,9 +714,9 @@ static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
     __ Mov(x0, argc);
     if (is_construct) {
       // No type feedback cell is available.
-      Handle<Object> undefined_sentinel(
-          masm->isolate()->heap()->undefined_value(), masm->isolate());
-      __ Mov(x2, Operand(undefined_sentinel));
+      Handle<Object> megamorphic_sentinel =
+          TypeFeedbackInfo::MegamorphicSentinel(masm->isolate());
+      __ Mov(x2, Operand(megamorphic_sentinel));
 
       CallConstructStub stub(NO_CALL_FUNCTION_FLAGS);
       __ CallStub(&stub);