Fix bug in string replace with nonparticipating captures.

src/runtime.cc

 // Copyright 2006-2009 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 3339 matching lines @@
       {
         // Avoid accumulating new handles inside loop.
         HandleScope temp_scope;
         // Arguments array to replace function is match, captures, index and
         // subject, i.e., 3 + capture count in total.
         Handle<FixedArray> elements = Factory::NewFixedArray(3 + capture_count);
         elements->set(0, *Factory::NewSubString(subject,
                                                 match_start,
                                                 match_end));
         for (int i = 1; i <= capture_count; i++) {
-          Handle<String> substring =
-              Factory::NewSubString(subject,
-                                    register_vector[i * 2],
-                                    register_vector[i * 2 + 1]);
-          elements->set(i, *substring);
+          int start = register_vector[i * 2];
+          if (start >= 0) {
+            int end = register_vector[i * 2 + 1];
+            ASSERT(start <= end);
+            Handle<String> substring = Factory::NewSubString(subject, start, end);
+            elements->set(i, *substring);
+          } else {
+            ASSERT(register_vector[i * 2 + 1] < 0);
+            elements->set(i, Heap::undefined_value());
+          }
         }
         elements->set(capture_count + 1, Smi::FromInt(match_start));
         elements->set(capture_count + 2, *subject);
         builder->Add(*Factory::NewJSArrayWithElements(elements));
       }
       // Swap register vectors, so the last successful match is in
       // prev_register_vector.
       Vector<int> tmp = prev_register_vector;
       prev_register_vector = register_vector;
       register_vector = tmp;
@@ skipping 6657 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal