Add Null class to dart:core.

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 399 matching lines @@
     cls.set_is_type_finalized();
     cls.raw_ptr()->type_arguments_field_offset_in_words_ =
         Class::kNoTypeArguments;
     cls.raw_ptr()->num_native_fields_ = 0;
     cls.InitEmptyFields();
     isolate->RegisterClass(cls);
   }
 
   // Allocate and initialize the null class.
   cls = Class::New<Instance>(kNullCid);
-  cls.set_is_finalized();
-  cls.set_is_type_finalized();
+  cls.set_is_prefinalized();
   isolate->object_store()->set_null_class(cls);
 
   // Allocate and initialize the free list element class.
   cls = Class::New<FreeListElement::FakeInstance>(kFreeListElement);
   cls.set_is_finalized();
   cls.set_is_type_finalized();
 
   // Allocate and initialize the sentinel values of Null class.
   {
     *sentinel_ ^=
@@ skipping 419 matching lines @@
   // remaining classes and register them by name in the dictionaries.
   String& name = String::Handle();
   cls = Class::New<Bool>();
   object_store->set_bool_class(cls);
   RegisterClass(cls, Symbols::Bool(), core_lib);
   pending_classes.Add(cls, Heap::kOld);
 
   // TODO(12364): The class 'Null' is not registered in the class dictionary
   // because it is not exported by dart:core.
   cls = Class::New<Instance>(kNullCid);
-  cls.set_name(Symbols::Null());
-  // We immediately mark Null as finalized because it has no corresponding
-  // source.
-  cls.set_is_finalized();
-  cls.set_is_type_finalized();
   object_store->set_null_class(cls);
-  cls.set_library(core_lib);  // A sort of fiction for the mirrors.
-  // When/if we promote Null to an ordinary class, it should be added to the
-  // core library, given source and added to the list of classes pending
-  // finalization.
-  // RegisterClass(cls, Symbols::Null(), core_lib);
-  // pending_classes.Add(cls, Heap::kOld);
+  cls.set_is_prefinalized();
+  RegisterClass(cls, Symbols::Null(), core_lib);
+  pending_classes.Add(cls, Heap::kOld);
 
   cls = object_store->array_class();  // Was allocated above.
   RegisterPrivateClass(cls, Symbols::ObjectArray(), core_lib);
   pending_classes.Add(cls, Heap::kOld);
   // We cannot use NewNonParameterizedType(cls), because Array is parameterized.
   type ^= Type::New(Object::Handle(cls.raw()),
                     TypeArguments::Handle(),
                     Scanner::kDummyTokenIndex);
   type.SetIsFinalized();
   type ^= type.Canonicalize();
@@ skipping 9592 matching lines @@
 RawString* AbstractType::ClassName() const {
   if (HasResolvedTypeClass()) {
     return Class::Handle(type_class()).Name();
   } else {
     return UnresolvedClass::Handle(unresolved_class()).Name();
   }
 }
 
 
 bool AbstractType::IsNullType() const {
-  ASSERT(Type::Handle(Type::NullType()).IsCanonical());
-  return raw() == Type::NullType();
+  return HasResolvedTypeClass() &&
+      (type_class() == Type::Handle(Type::NullType()).type_class());
 }
 
 
 bool AbstractType::IsBoolType() const {
   return HasResolvedTypeClass() &&
       (type_class() == Type::Handle(Type::BoolType()).type_class());
 }
 
 
 bool AbstractType::IsIntType() const {
@@ skipping 4122 matching lines @@
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   stream->OpenObject();
   stream->CloseObject();
 }
 
 
 }  // namespace dart