Add Object::IsNullOrUndefined(Isolate*) helper method

src/objects.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 1144 matching lines @@
 // data members can be present in Object.
 class Object {
  public:
   // Type testing.
   bool IsObject() const { return true; }
 
 #define IS_TYPE_FUNCTION_DECL(Type) INLINE(bool Is##Type() const);
   OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
   HEAP_OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
 #undef IS_TYPE_FUNCTION_DECL
+
 #define IS_TYPE_FUNCTION_DECL(Type, Value) \
   INLINE(bool Is##Type(Isolate* isolate) const);
   ODDBALL_LIST(IS_TYPE_FUNCTION_DECL)
 #undef IS_TYPE_FUNCTION_DECL
 
+  INLINE(bool IsNullOrUndefined(Isolate* isolate) const);
+
   // A non-keyed store is of the form a.x = foo or a["x"] = foo whereas
   // a keyed store is of the form a[expression] = foo.
   enum StoreFromKeyed {
     MAY_BE_STORE_FROM_KEYED,
     CERTAINLY_NOT_STORE_FROM_KEYED
   };
 
   enum ShouldThrow { THROW_ON_ERROR, DONT_THROW };
 
 #define RETURN_FAILURE(isolate, should_throw, call) \
@@ skipping 524 matching lines @@
 
 #define IS_TYPE_FUNCTION_DECL(Type) INLINE(bool Is##Type() const);
   HEAP_OBJECT_TYPE_LIST(IS_TYPE_FUNCTION_DECL)
 #undef IS_TYPE_FUNCTION_DECL
 
 #define IS_TYPE_FUNCTION_DECL(Type, Value) \
   INLINE(bool Is##Type(Isolate* isolate) const);
   ODDBALL_LIST(IS_TYPE_FUNCTION_DECL)
 #undef IS_TYPE_FUNCTION_DECL
 
+  INLINE(bool IsNullOrUndefined(Isolate* isolate) const);
+
 #define DECLARE_STRUCT_PREDICATE(NAME, Name, name) \
   INLINE(bool Is##Name() const);
   STRUCT_LIST(DECLARE_STRUCT_PREDICATE)
 #undef DECLARE_STRUCT_PREDICATE
 
   // Converts an address to a HeapObject pointer.
   static inline HeapObject* FromAddress(Address address) {
     DCHECK_TAG_ALIGNED(address);
     return reinterpret_cast<HeapObject*>(address + kHeapObjectTag);
   }
@@ skipping 10027 matching lines @@
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #include "src/objects/object-macros-undef.h"
 
 #endif  // V8_OBJECTS_H_