Enable optimization of top-level code.

src/x64/lithium-x64.h

 // 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 69 matching lines @@
   V(ClassOfTestAndBranch)                       \
   V(CmpConstantEqAndBranch)                     \
   V(CmpIDAndBranch)                             \
   V(CmpObjectEqAndBranch)                       \
   V(CmpMapAndBranch)                            \
   V(CmpT)                                       \
   V(ConstantD)                                  \
   V(ConstantI)                                  \
   V(ConstantT)                                  \
   V(Context)                                    \
+  V(DeclareGlobals)                             \
   V(DeleteProperty)                             \
   V(Deoptimize)                                 \
   V(DivI)                                       \
   V(DoubleToI)                                  \
   V(ElementsKind)                               \
   V(FixedArrayBaseLength)                       \
   V(FunctionLiteral)                            \
   V(GetCachedArrayIndex)                        \
   V(GlobalObject)                               \
   V(GlobalReceiver)                             \
@@ skipping 1238 matching lines @@
   explicit LOuterContext(LOperand* context) {
     inputs_[0] = context;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(OuterContext, "outer-context")
 
   LOperand* context() { return InputAt(0); }
 };
 
 
+class LDeclareGlobals: public LTemplateInstruction<0, 0, 0> {
+ public:
+  DECLARE_CONCRETE_INSTRUCTION(DeclareGlobals, "declare-globals")
+  DECLARE_HYDROGEN_ACCESSOR(DeclareGlobals)
+};
+
+
 class LGlobalObject: public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(GlobalObject, "global-object")
 };
 
 
 class LGlobalReceiver: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LGlobalReceiver(LOperand* global_object) {
     inputs_[0] = global_object;
@@ skipping 896 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_