Add HLoadRoot hydrogen instruction.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 2870 matching lines @@
   // Non-instance prototype: Fetch prototype from constructor field
   // in the function's map.
   __ bind(&non_instance);
   __ movq(result, FieldOperand(result, Map::kConstructorOffset));
 
   // All done.
   __ bind(&done);
 }
 
 
+void LCodeGen::DoLoadRoot(LLoadRoot* instr) {
+  Register result = ToRegister(instr->result());
+  __ LoadRoot(result, instr->index());
+}
+
+
 void LCodeGen::DoLoadExternalArrayPointer(
     LLoadExternalArrayPointer* instr) {
   Register result = ToRegister(instr->result());
   Register input = ToRegister(instr->object());
   __ movq(result, FieldOperand(input,
                                ExternalPixelArray::kExternalPointerOffset));
 }
 
 
 void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
@@ skipping 2619 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64