Fix performance regression introduced in r28961

src/bootstrapper.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/code-stubs.h"
@@ skipping 580 matching lines @@
   PropertyAttributes rw_attribs =
       static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE);
   PropertyAttributes ro_attribs =
       static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY);
   PropertyAttributes roc_attribs =
       static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY);
 
   // Add length.
   if (function_mode == BOUND_FUNCTION) {
     Handle<String> length_string = isolate()->factory()->length_string();
-    DataDescriptor d(length_string, 0, ro_attribs, Representation::Tagged());
+    DataDescriptor d(length_string, 0, roc_attribs, Representation::Tagged());
     map->AppendDescriptor(&d);
   } else {
     DCHECK(function_mode == FUNCTION_WITH_WRITEABLE_PROTOTYPE ||
            function_mode == FUNCTION_WITH_READONLY_PROTOTYPE ||
            function_mode == FUNCTION_WITHOUT_PROTOTYPE);
     Handle<AccessorInfo> length =
         Accessors::FunctionLengthInfo(isolate(), roc_attribs);
     AccessorConstantDescriptor d(Handle<Name>(Name::cast(length->name())),
                                  length, roc_attribs);
     map->AppendDescriptor(&d);
@@ skipping 2586 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8