Add inline caches for loading non-existing properties.

src/x64/stub-cache-x64.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1126 matching lines @@
   __ movq(rax, Operand(rsp, kPointerSize));
   GenerateLoadConstant(object, holder, rax, rbx, rdx, value, name, &miss);
   __ bind(&miss);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
 
   // Return the generated code.
   return GetCode(CONSTANT_FUNCTION, name);
 }
 
 
+Object* LoadStubCompiler::CompileLoadNonExisting(JSObject* object) {
+  // ----------- S t a t e -------------
+  //  -- rcx    : name
+  //  -- rsp[0] : return address
+  //  -- rsp[8] : receiver
+  // -----------------------------------
+  Label miss;
+
+  // Load receiver.
+  __ movq(rax, Operand(rsp, kPointerSize));
+
+  // Check the maps of the full prototype chain.
+  JSObject* last = object;
+  while (last->GetPrototype() != Heap::null_value()) {
+    last = JSObject::cast(last->GetPrototype());
+  }
+  CheckPrototypes(object, rax, last, rbx, rdx, Heap::empty_string(), &miss);
+
+  // Return undefined if maps of the full prototype chain is still the same.
+  __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
+  __ ret(0);
+
+  __ bind(&miss);
+  GenerateLoadMiss(masm(), Code::LOAD_IC);
+
+  // Return the generated code.
+  return GetCode(NON_EXISTING, Heap::empty_string());
+}
+
+
 Object* LoadStubCompiler::CompileLoadField(JSObject* object,
                                            JSObject* holder,
                                            int index,
                                            String* name) {
   // ----------- S t a t e -------------
   //  -- rcx    : name
   //  -- rsp[0] : return address
   //  -- rsp[8] : receiver
   // -----------------------------------
   Label miss;
@@ skipping 802 matching lines @@
   __ Jump(generic_construct_stub, RelocInfo::CODE_TARGET);
 
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal