diff -r 572668ef742b -r e3c851a14f16 src/Heap.cpp
--- a/src/Heap.cpp	Tue Dec 25 17:02:07 2012 -0800
+++ b/src/Heap.cpp	Tue Dec 25 18:13:02 2012 -0800
@@ -350,7 +350,7 @@
 Heap::sweep()
 {
     // Before destroying mark bits, sweep weak roots.
-    zone_->symbols()->sweep();
+    zone_->sweepWeakRoots();
 
     // Note: we don't bother sweeping the LIFO space.
     SweepOldSpace(&mapSpace_);