Move the temporary private freelist closer to where it's used

src/mark-compact.cc

 // Copyright 2012 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 3953 matching lines @@
     freed_bytes += Free<mode>(space, free_list, free_start,
                               static_cast<int>(p->area_end() - free_start));
   }
 
   p->ResetLiveBytes();
   return freed_bytes;
 }
 
 
 void MarkCompactCollector::SweepInParallel(PagedSpace* space,
-                                           FreeList* private_free_list,
                                            FreeList* free_list) {
   PageIterator it(space);
+  FreeList private_free_list(space);
   while (it.has_next()) {
     Page* p = it.next();
 
     if (p->TryParallelSweeping()) {
-      SweepConservatively<SWEEP_IN_PARALLEL>(space, private_free_list, p);
-      free_list->Concatenate(private_free_list);
+      SweepConservatively<SWEEP_IN_PARALLEL>(space, &private_free_list, p);
+      free_list->Concatenate(&private_free_list);
     }
   }
 }
 
 
 void MarkCompactCollector::SweepSpace(PagedSpace* space, SweeperType sweeper) {
   space->set_was_swept_conservatively(sweeper == CONSERVATIVE ||
                                       sweeper == LAZY_CONSERVATIVE ||
                                       sweeper == PARALLEL_CONSERVATIVE ||
                                       sweeper == CONCURRENT_CONSERVATIVE);
@@ skipping 376 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal