VM: Explicitly load function and context before calling a closure.

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 35546)
+++ runtime/vm/object.h	(working copy)
@@ -435,6 +435,7 @@
   static RawClass* void_class() { return void_class_; }
   static RawType* dynamic_type() { return dynamic_type_; }
   static RawType* void_type() { return void_type_; }
+  static RawType* function_type() { return function_type_; }

[regis, 2014/04/30 18:23:15]

You should not introduce this type. This is not a Dart type.
You will never do any type check on it. The type of the function field in a
closure should either be null or dynamic.
This is similar to the parent field in a context. It has no Dart type. I think
it is null in that case.

[Florian Schneider, 2014/04/30 18:57:33]

Done. I changed flow_graph_type_propagator instead to never create a
AbstractType from a value with kFunctionCid.

   static RawClass* unresolved_class_class() { return unresolved_class_class_; }
   static RawClass* type_arguments_class() { return type_arguments_class_; }
   static RawClass* patch_class_class() { return patch_class_class_; }
@@ -591,6 +592,7 @@
   static RawClass* void_class_;  // Class of the 'void' type.
   static RawType* dynamic_type_;  // Class of the 'dynamic' type.
   static RawType* void_type_;  // Class of the 'void' type.
+  static RawType* function_type_;  // Type of the 'Function' vm class.

[regis, 2014/04/30 18:23:15]

ditto

   static RawClass* unresolved_class_class_;  // Class of UnresolvedClass.
   static RawClass* type_arguments_class_;  // Class of TypeArguments vm object.
   static RawClass* patch_class_class_;  // Class of the PatchClass vm object.