Remove bogus writability check in DefineGetterSetter.

src/runtime.cc

 // Copyright 2011 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 4230 matching lines @@
 // Steps 9c & 12 - replace an existing data property with an accessor property.
 // Step 12 - update an existing accessor property with an accessor or generic
 //           descriptor.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DefineOrRedefineAccessorProperty) {
   ASSERT(args.length() == 5);
   HandleScope scope(isolate);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   CONVERT_CHECKED(String, name, args[1]);
   CONVERT_CHECKED(Smi, flag_setter, args[2]);
   Object* fun = args[3];
-  RUNTIME_ASSERT(fun->IsSpecFunction() || fun->IsUndefined());
   CONVERT_CHECKED(Smi, flag_attr, args[4]);
+
   int unchecked = flag_attr->value();
   RUNTIME_ASSERT((unchecked & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
+  PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
+
   RUNTIME_ASSERT(!obj->IsNull());
-  LookupResult result(isolate);
-  obj->LocalLookupRealNamedProperty(name, &result);
-
-  PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
-  // If an existing property is either FIELD, NORMAL or CONSTANT_FUNCTION
-  // delete it to avoid running into trouble in DefineAccessor, which
-  // handles this incorrectly if the property is readonly (does nothing)
-  if (result.IsProperty() &&
-      (result.type() == FIELD || result.type() == NORMAL
-       || result.type() == CONSTANT_FUNCTION)) {
-    Object* ok;
-    { MaybeObject* maybe_ok =
-          obj->DeleteProperty(name, JSReceiver::NORMAL_DELETION);
-      if (!maybe_ok->ToObject(&ok)) return maybe_ok;
-    }
-  }
+  RUNTIME_ASSERT(fun->IsSpecFunction() || fun->IsUndefined());
   return obj->DefineAccessor(name, flag_setter->value() == 0, fun, attr);
 }
 
 // Implements part of 8.12.9 DefineOwnProperty.
 // There are 3 cases that lead here:
 // Step 4a - define a new data property.
 // Steps 9b & 12 - replace an existing accessor property with a data property.
 // Step 12 - update an existing data property with a data or generic
 //           descriptor.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_DefineOrRedefineDataProperty) {
   ASSERT(args.length() == 4);
   HandleScope scope(isolate);
   CONVERT_ARG_CHECKED(JSObject, js_object, 0);
   CONVERT_ARG_CHECKED(String, name, 1);
   Handle<Object> obj_value = args.at<Object>(2);
+  CONVERT_CHECKED(Smi, flag, args[3]);
 
-  CONVERT_CHECKED(Smi, flag, args[3]);
   int unchecked = flag->value();
   RUNTIME_ASSERT((unchecked & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
-
   PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
 
   // Check if this is an element.
   uint32_t index;
   bool is_element = name->AsArrayIndex(&index);
 
   // Special case for elements if any of the flags might be involved.
   // If elements are in fast case we always implicitly assume that:
   // DONT_DELETE: false, DONT_ENUM: false, READ_ONLY: false.
   if (is_element && (attr != NONE ||
@@ skipping 9283 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags);
   }
 }
 
 
 } }  // namespace v8::internal