GC_apply_to_each_object  339 gc/backgraph.c   GC_apply_to_each_object(add_back_edges);
GC_apply_to_each_object  446 gc/backgraph.c   GC_apply_to_each_object(update_max_height);
GC_apply_to_each_object  463 gc/backgraph.c   GC_apply_to_each_object(reset_back_edge);