Add void operator to fast compiler.

src/x64/fast-codegen-x64.cc

 // Copyright 2009 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 723 matching lines @@
   for (int i = 0; i < arg_count; i++) {
     Visit(args->at(i));
     ASSERT_EQ(Expression::kValue, args->at(i)->context());
   }
 
   __ CallRuntime(function, arg_count);
   Move(expr->context(), rax);
 }
 
 
+void FastCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
+  Comment cmnt(masm_, "[ UnaryOperation");
+
+  switch (expr->op()) {
+    case Token::VOID:
+      Visit(expr->expression());
+      ASSERT_EQ(Expression::kEffect, expr->expression()->context());
+      switch (expr->context()) {
+        case Expression::kUninitialized:
+          UNREACHABLE();
+          break;
+        case Expression::kValue:
+          __ PushRoot(Heap::kUndefinedValueRootIndex);
+          break;
+        case Expression::kEffect:
+          break;
+      }
+      break;
+
+    default:
+      UNREACHABLE();
+  }
+}
+
+
 void FastCodeGenerator::VisitBinaryOperation(BinaryOperation* expr) {
   switch (expr->op()) {
     case Token::COMMA:
       ASSERT_EQ(Expression::kEffect, expr->left()->context());
       ASSERT_EQ(expr->context(), expr->right()->context());
       Visit(expr->left());
       Visit(expr->right());
       break;
 
     case Token::OR:
@@ skipping 114 matching lines @@
   }
   // Save or discard the right-hand value as needed.
   Visit(right);
   ASSERT_EQ(context, right->context());
 
   __ bind(&done);
 }
 
 
 } }  // namespace v8::internal