Tentative implementation of string slices (hidden under the flag --string-slices).

src/interpreter-irregexp.cc

 // Copyright 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 617 matching lines @@
 bool IrregexpInterpreter::Match(Isolate* isolate,
                                 Handle<ByteArray> code_array,
                                 Handle<String> subject,
                                 int* registers,
                                 int start_position) {
   ASSERT(subject->IsFlat());
 
   AssertNoAllocation a;
   const byte* code_base = code_array->GetDataStartAddress();
   uc16 previous_char = '\n';
-  if (subject->IsAsciiRepresentation()) {
+
+  if (subject->IsAsciiRepresentationUnderneath()) {
     Vector<const char> subject_vector = subject->ToAsciiVector();
     if (start_position != 0) previous_char = subject_vector[start_position - 1];
     return RawMatch(isolate,
                     code_base,
                     subject_vector,
                     registers,
                     start_position,
                     previous_char);
   } else {
     Vector<const uc16> subject_vector = subject->ToUC16Vector();
     if (start_position != 0) previous_char = subject_vector[start_position - 1];
     return RawMatch(isolate,
                     code_base,
                     subject_vector,
                     registers,
                     start_position,
                     previous_char);
   }
 }
 
 } }  // namespace v8::internal