Use AST's type field and merge types for unary, binary & compare ICs

src/globals.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 381 matching lines @@
 // neither in strict nor extended mode. However, the more distinguishing term
 // 'classic mode' is used in V8 instead to avoid mix-ups.
 
 enum LanguageMode {
   CLASSIC_MODE,
   STRICT_MODE,
   EXTENDED_MODE
 };
 
 
+// A simple Maybe type, that can be passed by value.
+template<class T>
+struct Maybe {
+  Maybe() : has_value(false) {}
+  explicit Maybe(T t) : has_value(true), value(t) {}
+  Maybe(bool has, T t) : has_value(has), value(t) {}
+
+  bool has_value;
+  T value;
+};
+
+
 // The Strict Mode (ECMA-262 5th edition, 4.2.2).
 //
 // This flag is used in the backend to represent the language mode. So far
 // there is no semantic difference between the strict and the extended mode in
 // the backend, so both modes are represented by the kStrictMode value.
 enum StrictModeFlag {
   kNonStrictMode,
   kStrictMode
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBALS_H_