Introduce exception object and remove some uses of MaybeObject::IsFailure().

src/objects.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 1424 matching lines @@
   STRUCT_LIST(DECLARE_STRUCT_PREDICATE)
 #undef DECLARE_STRUCT_PREDICATE
 
   INLINE(bool IsSpecObject());
   INLINE(bool IsSpecFunction());
   bool IsCallable();
 
   // Oddball testing.
   INLINE(bool IsUndefined());
   INLINE(bool IsNull());
-  INLINE(bool IsTheHole());  // Shadows MaybeObject's implementation.
+  INLINE(bool IsTheHole());
+  INLINE(bool IsException());
   INLINE(bool IsUninitialized());
   INLINE(bool IsTrue());
   INLINE(bool IsFalse());
   inline bool IsArgumentsMarker();
   inline bool NonFailureIsHeapObject();
 
   // Filler objects (fillers and free space objects).
   inline bool IsFiller();
 
   // Extract the number.
@@ skipping 60 matching lines @@
   static inline MaybeHandle<JSReceiver> ToObject(Isolate* isolate,
                                                  Handle<Object> object);
   static MaybeHandle<JSReceiver> ToObject(Isolate* isolate,
                                           Handle<Object> object,
                                           Handle<Context> context);
 
   // Converts this to a Smi if possible.
   // Failure is returned otherwise.
   static MUST_USE_RESULT inline Handle<Object> ToSmi(Isolate* isolate,
                                                      Handle<Object> object);
-  MUST_USE_RESULT inline MaybeObject* ToSmi();
 
   void Lookup(Name* name, LookupResult* result);
 
   MUST_USE_RESULT static MaybeHandle<Object> GetPropertyWithReceiver(
       Handle<Object> object,
       Handle<Object> receiver,
       Handle<Name> name,
       PropertyAttributes* attributes);
   MUST_USE_RESULT static inline MaybeHandle<Object> GetPropertyOrElement(
       Handle<Object> object,
@@ skipping 8242 matching lines @@
 
   static const byte kFalse = 0;
   static const byte kTrue = 1;
   static const byte kNotBooleanMask = ~1;
   static const byte kTheHole = 2;
   static const byte kNull = 3;
   static const byte kArgumentMarker = 4;
   static const byte kUndefined = 5;
   static const byte kUninitialized = 6;
   static const byte kOther = 7;
+  static const byte kException = 8;
 
   typedef FixedBodyDescriptor<kToStringOffset,
                               kToNumberOffset + kPointerSize,
                               kSize> BodyDescriptor;
 
   STATIC_CHECK(kKindOffset == Internals::kOddballKindOffset);
   STATIC_CHECK(kNull == Internals::kNullOddballKind);
   STATIC_CHECK(kUndefined == Internals::kUndefinedOddballKind);
 
  private:
@@ skipping 1305 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_