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 395 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 406 matching lines @@
   // Now that the symbol table is initialized and that the core dictionary as
   // well as the core implementation dictionary have been setup, preallocate
   // 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);
 
   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 239 matching lines @@
   object_store->set_bool_type(type);
 
   cls = object_store->smi_class();
   type = Type::NewNonParameterizedType(cls);
   object_store->set_smi_type(type);
 
   cls = object_store->mint_class();
   type = Type::NewNonParameterizedType(cls);
   object_store->set_mint_type(type);
 
   // The class 'Null' is not register in the class dictionary because it is not

[Florian Schneider, 2013/08/14 12:22:12]

Not from your code: This comment about the  Null class is not meaningful.

[rmacnak, 2013/08/14 16:25:30]

This will be cleaned up in https://chromiumcodereview.appspot.com/22819005/

[Lasse Reichstein Nielsen, 2013/08/15 12:24:44]

Leaving it untouched.

   // The classes 'void' and 'dynamic' are phoney classes to make type checking
   // more regular; they live in the VM isolate. The class 'void' is not
   // registered in the class dictionary because its name is a reserved word.
   // The class 'dynamic' is registered in the class dictionary because its name
   // is a built-in identifier (this is wrong).
   // The corresponding types are stored in the object store.
   cls = object_store->null_class();
   type = Type::NewNonParameterizedType(cls);
   object_store->set_null_type(type);
 
@@ skipping 13484 matching lines @@
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   stream->OpenObject();
   stream->CloseObject();
 }
 
 
 }  // namespace dart