Parallel and concurrent sweeping.

tools/gyp/v8.gyp

 # 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 443 matching lines @@
             '../../src/store-buffer.cc',
             '../../src/store-buffer.h',
             '../../src/string-search.cc',
             '../../src/string-search.h',
             '../../src/string-stream.cc',
             '../../src/string-stream.h',
             '../../src/strtod.cc',
             '../../src/strtod.h',
             '../../src/stub-cache.cc',
             '../../src/stub-cache.h',
+            '../../src/sweeper-thread.h',
+            '../../src/sweeper-thread.cc',
             '../../src/token.cc',
             '../../src/token.h',
             '../../src/transitions-inl.h',
             '../../src/transitions.cc',
             '../../src/transitions.h',
             '../../src/type-info.cc',
             '../../src/type-info.h',
             '../../src/unbound-queue-inl.h',
             '../../src/unbound-queue.h',
             '../../src/unicode-inl.h',
@@ skipping 571 matching lines @@
             }],
           ],
           'dependencies': [
             'v8'
           ],
         },
       ],
     }],
   ],
 }