Add initial hydrogenized NewStringAddStub.

src/code-stubs-hydrogen.cc

 // Copyright 2012 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 954 matching lines @@
   return result;
 }
 
 
 Handle<Code> BinaryOpStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 template <>
+HValue* CodeStubGraphBuilder<NewStringAddStub>::BuildCodeInitializedStub() {
+  NewStringAddStub* stub = casted_stub();
+  StringAddFlags flags = stub->flags();
+  PretenureFlag pretenure_flag = stub->pretenure_flag();
+
+  HValue* left = GetParameter(NewStringAddStub::kLeft);
+  HValue* right = GetParameter(NewStringAddStub::kRight);
+
+  // Make sure that both arguments are strings if not known in advance.
+  if ((flags & STRING_ADD_CHECK_LEFT) == STRING_ADD_CHECK_LEFT) {
+    IfBuilder if_leftnotstring(this);
+    if_leftnotstring.IfNot<HIsStringAndBranch>(left);
+    if_leftnotstring.Then();
+    if_leftnotstring.Deopt("Expected string for LHS of string addition");
+  }
+  if ((flags & STRING_ADD_CHECK_RIGHT) == STRING_ADD_CHECK_RIGHT) {
+    IfBuilder if_rightnotstring(this);
+    if_rightnotstring.IfNot<HIsStringAndBranch>(right);
+    if_rightnotstring.Then();
+    if_rightnotstring.Deopt("Expected string for RHS of string addition");
+  }
+
+  return BuildStringAdd(left, right, pretenure_flag);
+}
+
+
+Handle<Code> NewStringAddStub::GenerateCode(Isolate* isolate) {
+  return DoGenerateCode(isolate, this);
+}
+
+
+template <>
 HValue* CodeStubGraphBuilder<ToBooleanStub>::BuildCodeInitializedStub() {
   ToBooleanStub* stub = casted_stub();
 
   IfBuilder if_true(this);
   if_true.If<HBranch>(GetParameter(0), stub->GetTypes());
   if_true.Then();
   if_true.Return(graph()->GetConstant1());
   if_true.Else();
   if_true.End();
   return graph()->GetConstant0();
@@ skipping 270 matching lines @@
   return js_function;
 }
 
 
 Handle<Code> FastNewClosureStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 } }  // namespace v8::internal