Fix direct loading of global function prototypes:

src/stub-cache.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 352 matching lines @@
   Object* CompileCallDebugBreak(Code::Flags flags);
   Object* CompileCallDebugPrepareStepIn(Code::Flags flags);
 #endif
 
   // Static functions for generating parts of stubs.
   static void GenerateLoadGlobalFunctionPrototype(MacroAssembler* masm,
                                                   int index,
                                                   Register prototype);
 
   // Generates prototype loading code that uses the objects from the
-  // context we were in when this function was called.  This ties the
-  // generated code to a particular context and so must not be used in
-  // cases where the generated code is not allowed to have references
-  // to objects from a context.
+  // context we were in when this function was called. If the context
+  // has changed, a jump to miss is performed. This ties the generated
+  // code to a particular context and so must not be used in cases
+  // where the generated code is not allowed to have references to
+  // objects from a context.
   static void GenerateDirectLoadGlobalFunctionPrototype(MacroAssembler* masm,
                                                         int index,
-                                                        Register prototype);
+                                                        Register prototype,
+                                                        Label* miss);
 
   static void GenerateFastPropertyLoad(MacroAssembler* masm,
                                        Register dst, Register src,
                                        JSObject* holder, int index);
 
   static void GenerateLoadArrayLength(MacroAssembler* masm,
                                       Register receiver,
                                       Register scratch,
                                       Label* miss_label);
 
@@ skipping 380 matching lines @@
 
   JSFunction* constant_function_;
   bool is_simple_api_call_;
   FunctionTemplateInfo* expected_receiver_type_;
   CallHandlerInfo* api_call_info_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_STUB_CACHE_H_