Trim fast elements tail on significant length decreases.

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 3514 matching lines @@
   CONVERT_ARG_CHECKED(JSRegExp, regexp, 0);
   CONVERT_ARG_CHECKED(JSArray, last_match_info, 2);
   CONVERT_ARG_CHECKED(JSArray, result_array, 3);
 
   ASSERT(last_match_info->HasFastElements());
   ASSERT(regexp->GetFlags().is_global());
   Handle<FixedArray> result_elements;
   if (result_array->HasFastElements()) {
     result_elements =
         Handle<FixedArray>(FixedArray::cast(result_array->elements()));
-  } else {
+  }
+  if (result_elements.is_null() || result_elements->length() < 16) {

[Mads Ager (chromium), 2011/06/23 06:37:04]

Is this an unrelated change?

[Mads Ager (chromium), 2011/06/23 08:54:08]

Nevermind, just read the change description. :-)

     result_elements = isolate->factory()->NewFixedArrayWithHoles(16);
   }
   FixedArrayBuilder builder(result_elements);
 
   if (regexp->TypeTag() == JSRegExp::ATOM) {
     Handle<String> pattern(
         String::cast(regexp->DataAt(JSRegExp::kAtomPatternIndex)));
     ASSERT(pattern->IsFlat());
     if (SearchStringMultiple(isolate, subject, pattern,
                              last_match_info, &builder)) {
@@ skipping 8936 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(false);
   }
 }
 
 
 } }  // namespace v8::internal