Introduce a class encapsulating arguments descriptor arrays.

runtime/vm/flow_graph_inliner.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_inliner.h"
 
 #include "vm/compiler.h"
 #include "vm/flags.h"
 #include "vm/flow_graph.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 412 matching lines @@
       // If the callee has optional parameters, rebuild the argument and stub
       // arrays so that actual arguments are in one-to-one with the formal
       // parameters.
       if (function.HasOptionalParameters()) {
         TRACE_INLINING(OS::Print("     adjusting for optional parameters\n"));
         AdjustForOptionalParameters(*parsed_function,
                                     argument_names,
                                     arguments,
                                     &param_stubs,
                                     callee_graph);
-        // Add a bogus parameter at the end for the (unused) argument descriptor
-        // slot. The parser allocates an extra slot between locals and
-        // parameters to hold the argument descriptor in case it escapes.  We
-        // currently bailout if there are argument test expressions or escaping
-        // variables so this parameter and the stack slot are not used.
+        // Add a bogus parameter at the end for the (unused) arguments
+        // descriptor slot. The parser allocates an extra slot between
+        // locals and parameters to hold the arguments descriptor in case it
+        // escapes.  We currently bailout if there are argument test
+        // expressions or escaping variables so this parameter and the stack
+        // slot are not used.
         if (parsed_function->GetSavedArgumentsDescriptorVar() != NULL) {
           param_stubs.Add(new ParameterInstr(
               function.NumParameters(), callee_graph->graph_entry()));
         }
       }
 
       // After treating optional parameters the actual/formal count must match.
       ASSERT(arguments->length() == function.NumParameters());
       ASSERT(param_stubs.length() == callee_graph->parameter_count());
 
@@ skipping 350 matching lines @@
         OS::Print("After Inlining of %s\n", flow_graph_->
                   parsed_function().function().ToFullyQualifiedCString());
         FlowGraphPrinter printer(*flow_graph_);
         printer.PrintBlocks();
       }
     }
   }
 }
 
 }  // namespace dart