Added %_NewConsString intrinsic.

src/runtime/runtime-strings.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/arguments.h"
 #include "src/jsregexp-inl.h"
 #include "src/jsregexp.h"
 #include "src/runtime/runtime-utils.h"
@@ skipping 1203 matching lines @@
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
         isolate, result, isolate->factory()->NewRawOneByteString(length));
   } else {
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
         isolate, result, isolate->factory()->NewRawTwoByteString(length));
   }
   return *result;
 }
 
 
+RUNTIME_FUNCTION(Runtime_NewConsString) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 4);
+  CONVERT_INT32_ARG_CHECKED(length, 0);
+  CONVERT_BOOLEAN_ARG_CHECKED(is_one_byte, 1);
+  CONVERT_ARG_HANDLE_CHECKED(String, left, 2);
+  CONVERT_ARG_HANDLE_CHECKED(String, right, 3);
+
+  Handle<String> result;
+  if (is_one_byte) {
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, result,
+        isolate->factory()->NewOneByteConsString(length, left, right));
+  } else {
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, result,
+        isolate->factory()->NewTwoByteConsString(length, left, right));
+  }
+  return *result;
+}
+
+
 RUNTIME_FUNCTION(Runtime_StringEquals) {
   HandleScope handle_scope(isolate);
   DCHECK(args.length() == 2);
 
   CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
   CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
 
   bool not_equal = !String::Equals(x, y);
   // This is slightly convoluted because the value that signifies
   // equality is 0 and inequality is 1 so we have to negate the result
@@ skipping 88 matching lines @@
 
 
 RUNTIME_FUNCTION(Runtime_StringGetLength) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
   return Smi::FromInt(s->length());
 }
 }
 }  // namespace v8::internal