Added support for assignments to global variables in the toplevel code...

src/arm/codegen-arm.h

Index: src/arm/codegen-arm.h
===================================================================
--- src/arm/codegen-arm.h	(revision 3091)
+++ src/arm/codegen-arm.h	(working copy)
@@ -242,7 +242,7 @@
   void LoadReference(Reference* ref);
   void UnloadReference(Reference* ref);
 
-  MemOperand ContextOperand(Register context, int index) const {
+  static MemOperand ContextOperand(Register context, int index) {
     return MemOperand(context, Context::SlotOffset(index));
   }
 
@@ -254,7 +254,7 @@
                                                JumpTarget* slow);
 
   // Expressions
-  MemOperand GlobalObject() const  {
+  static MemOperand GlobalObject()  {
     return ContextOperand(cp, Context::GLOBAL_INDEX);
   }
 
@@ -425,6 +425,7 @@
   friend class VirtualFrame;
   friend class JumpTarget;
   friend class Reference;
+  friend class FastCodeGenerator;
 
   DISALLOW_COPY_AND_ASSIGN(CodeGenerator);
 };