Always create HArgumentsObject on function entry.

src/hydrogen.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 2595 matching lines @@
   return call;
 }
 
 
 void HGraphBuilder::SetUpScope(Scope* scope) {
   HConstant* undefined_constant = new(zone()) HConstant(
       isolate()->factory()->undefined_value(), Representation::Tagged());
   AddInstruction(undefined_constant);
   graph_->set_undefined_constant(undefined_constant);
 
+  HArgumentsObject* object = new(zone()) HArgumentsObject;
+  AddInstruction(object);
+  graph()->SetArgumentsObject(object);
+
   // Set the initial values of parameters including "this".  "This" has
   // parameter index 0.
   ASSERT_EQ(scope->num_parameters() + 1, environment()->parameter_count());
 
   for (int i = 0; i < environment()->parameter_count(); ++i) {
     HInstruction* parameter = AddInstruction(new(zone()) HParameter(i));
     environment()->Bind(i, parameter);
   }
 
   // First special is HContext.
   HInstruction* context = AddInstruction(new(zone()) HContext);
   environment()->BindContext(context);
 
   // Initialize specials and locals to undefined.
   for (int i = environment()->parameter_count() + 1;
        i < environment()->length();
        ++i) {
     environment()->Bind(i, undefined_constant);
   }
 
   // Handle the arguments and arguments shadow variables specially (they do
   // not have declarations).
   if (scope->arguments() != NULL) {
     if (!scope->arguments()->IsStackAllocated()) {
       return Bailout("context-allocated arguments");
     }
 
-    if (!graph()->HasArgumentsObject()) {
-      HArgumentsObject* object = new(zone()) HArgumentsObject;
-      AddInstruction(object);
-      graph()->SetArgumentsObject(object);
-    }
     environment()->Bind(scope->arguments(),
                         graph()->GetArgumentsObject());
   }
 }
 
 
 void HGraphBuilder::VisitStatements(ZoneList<Statement*>* statements) {
   for (int i = 0; i < statements->length(); i++) {
     CHECK_ALIVE(Visit(statements->at(i)));
   }
@@ skipping 2660 matching lines @@
   AddSimulate(return_id);
   current_block()->UpdateEnvironment(inner_env);
   AddInstruction(new(zone()) HEnterInlined(target,
                                            arguments->length(),
                                            function,
                                            call_kind,
                                            function_state()->is_construct()));
   // If the function uses arguments object create and bind one.
   if (function->scope()->arguments() != NULL) {
     ASSERT(function->scope()->arguments()->IsStackAllocated());
-    if (!graph()->HasArgumentsObject()) {
-      HArgumentsObject* object = new(zone()) HArgumentsObject;
-      AddInstruction(object);
-      graph()->SetArgumentsObject(object);
-    }
     environment()->Bind(function->scope()->arguments(),
                         graph()->GetArgumentsObject());
   }
   VisitDeclarations(target_info.scope()->declarations());
   VisitStatements(function->body());
   if (HasStackOverflow()) {
     // Bail out if the inline function did, as we cannot residualize a call
     // instead.
     TraceInline(target, caller, "inline graph construction failed");
     target_shared->DisableOptimization();
@@ skipping 2763 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal