Make Null a public class of dart:core.

runtime/vm/code_generator.cc

 // Copyright (c) 2013, 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/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/bigint_operations.h"
 #include "vm/code_patcher.h"
@@ skipping 1014 matching lines @@
 DEFINE_RUNTIME_ENTRY(MegamorphicCacheMissHandler, 3) {
   ASSERT(arguments.ArgCount() ==
      kMegamorphicCacheMissHandlerRuntimeEntry.argument_count());
   const Instance& receiver = Instance::CheckedHandle(arguments.ArgAt(0));
   const ICData& ic_data = ICData::CheckedHandle(arguments.ArgAt(1));
   const Array& descriptor = Array::CheckedHandle(arguments.ArgAt(2));
   const String& name = String::Handle(ic_data.target_name());
   const MegamorphicCache& cache = MegamorphicCache::Handle(
       isolate->megamorphic_cache_table()->Lookup(name, descriptor));
   Class& cls = Class::Handle(receiver.clazz());
-  const bool is_null = cls.IsNullClass();
-  // For lookups treat null as an instance of class Object.
-  if (is_null) {
-    cls = isolate->object_store()->object_class();
-  }
   ASSERT(!cls.IsNull());
   if (FLAG_trace_ic || FLAG_trace_ic_miss_in_optimized) {
     OS::PrintErr("Megamorphic IC miss, class=%s, function=%s\n",
                  cls.ToCString(), name.ToCString());
   }
 
   ArgumentsDescriptor args_desc(descriptor);
   const Function& target = Function::Handle(
       Resolver::ResolveDynamicForReceiverClass(cls,
                                                name,
                                                args_desc));
 
   Instructions& instructions = Instructions::Handle();
   if (!target.IsNull()) {
     if (!target.HasCode()) {
       const Error& error = Error::Handle(Compiler::CompileFunction(target));
       if (!error.IsNull()) {
         Exceptions::PropagateError(error);
       }
     }
     ASSERT(target.HasCode());
     instructions = Code::Handle(target.CurrentCode()).instructions();
   }
   arguments.SetReturn(instructions);
   if (instructions.IsNull()) return;
 
   cache.EnsureCapacity();
-  const Smi& class_id = Smi::Handle(Smi::New(
-      is_null ? static_cast<intptr_t>(kNullCid) : cls.id()));
+  const Smi& class_id = Smi::Handle(Smi::New(cls.id()));
   cache.Insert(class_id, target);
   return;
 }
 
 
 // Updates IC data for two arguments. Used by the equality operation when
 // the control flow bypasses regular inline cache (null arguments).
 //   Arg0: Receiver object.
 //   Arg1: Argument after receiver.
 //   Arg2: Target's name.
@@ skipping 131 matching lines @@
 //
 // 3. There is no such method.
 DEFINE_RUNTIME_ENTRY(InstanceFunctionLookup, 4) {
   ASSERT(arguments.ArgCount() ==
          kInstanceFunctionLookupRuntimeEntry.argument_count());
   const Instance& receiver = Instance::CheckedHandle(arguments.ArgAt(0));
   const ICData& ic_data = ICData::CheckedHandle(arguments.ArgAt(1));
   const Array& args_descriptor = Array::CheckedHandle(arguments.ArgAt(2));
   const Array& args = Array::CheckedHandle(arguments.ArgAt(3));
 
-  Class& receiver_class = Class::Handle(receiver.clazz());
-  // For lookups treat null as an instance of class Object.
-  if (receiver_class.IsNullClass()) {
-    receiver_class = isolate->object_store()->object_class();
-  }
+  const Class& receiver_class = Class::Handle(receiver.clazz());

[Lasse Reichstein Nielsen, 2013/08/16 08:04:13]

I like how this change makes code *simpler*! :)

   const String& target_name = String::Handle(ic_data.target_name());
 
   Object& result = Object::Handle();
   if (!ResolveCallThroughGetter(receiver,
                                 receiver_class,
                                 target_name,
                                 args_descriptor,
                                 args,
                                 ic_data,
                                 &result)) {
@@ skipping 632 matching lines @@
 //   Arg1: Value that is being stored.
 DEFINE_RUNTIME_ENTRY(UpdateFieldCid, 2) {
   ASSERT(arguments.ArgCount() == kUpdateFieldCidRuntimeEntry.argument_count());
   const Field& field = Field::CheckedHandle(arguments.ArgAt(0));
   const Object& value = Object::Handle(arguments.ArgAt(1));
 
   field.UpdateCid(value.GetClassId());
 }
 
 }  // namespace dart