MIPS: Fix the context check in LoadGlobalFunctionPrototype

src/mips/stub-cache-mips.cc

 // Copyright 2012 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 269 matching lines @@
   __ lw(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));
 }
 
 
 void StubCompiler::GenerateDirectLoadGlobalFunctionPrototype(
     MacroAssembler* masm,
     int index,
     Register prototype,
     Label* miss) {
   Isolate* isolate = masm->isolate();
-  // Check we're still in the same context.
-  __ lw(prototype,
-        MemOperand(cp, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
-  ASSERT(!prototype.is(at));
-  __ li(at, isolate->global_object());
-  __ Branch(miss, ne, prototype, Operand(at));
   // Get the global function with the given index.
   Handle<JSFunction> function(
       JSFunction::cast(isolate->native_context()->get(index)));
+
+  // Check we're still in the same context.
+  Register scratch = prototype;
+  const int offset = Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX);
+  __ lw(scratch, MemOperand(cp, offset));
+  __ lw(scratch, FieldMemOperand(scratch, GlobalObject::kNativeContextOffset));
+  __ lw(scratch, MemOperand(scratch, Context::SlotOffset(index)));
+  __ li(at, function);
+  __ Branch(miss, ne, at, Operand(scratch));
+
   // Load its initial map. The global functions all have initial maps.
   __ li(prototype, Handle<Map>(function->initial_map()));
   // Load the prototype from the initial map.
   __ lw(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));
 }
 
 
 void StubCompiler::GenerateFastPropertyLoad(MacroAssembler* masm,
                                             Register dst,
                                             Register src,
@@ skipping 1642 matching lines @@
   // -----------------------------------
   TailCallBuiltin(masm, Builtins::kKeyedLoadIC_Miss);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS