Fix bug where strings were not flattened before regexp.

src/objects.h

 // Copyright 2006-2008 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 3113 matching lines @@
   // use the length() and set_length methods.
   inline uint32_t length_field();
   inline void set_length_field(uint32_t value);
 
   // Get and set individual two byte chars in the string.
   inline void Set(StringShape shape, int index, uint16_t value);
   // Get individual two byte char in the string.  Repeated calls
   // to this method are not efficient unless the string is flat.
   inline uint16_t Get(StringShape shape, int index);
 
-  // Flatten the top level ConsString that is hiding behind this
+  // Try to flatten the top level ConsString that is hiding behind this
   // string.  This is a no-op unless the string is a ConsString or a
   // SlicedString.  Flatten mutates the ConsString and might return a
   // failure.
-  Object* Flatten(StringShape shape);
-  // Try to flatten the string.  Do not allow handling of allocation
-  // failures.  After calling TryFlatten, the string could still be a
-  // ConsString.
-  inline void TryFlatten(StringShape shape);
+  Object* TryFlatten(StringShape shape);
+
+  // Try to flatten the string.  Checks first inline to see if it is necessary.
+  // Do not handle allocation failures.  After calling TryFlattenIfNotFlat, the
+  // string could still be a ConsString, in which case a failure is returned.
+  // Use FlattenString from Handles.cc to be sure to flatten.
+  inline Object* TryFlattenIfNotFlat(StringShape shape);
 
   Vector<const char> ToAsciiVector();
   Vector<const uc16> ToUC16Vector();
 
   // Mark the string as an undetectable object. It only applies to
   // ascii and two byte string types.
   bool MarkAsUndetectable();
 
   // Slice the string and return a substring.
   Object* Slice(int from, int to);
@@ skipping 1066 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_