_descr            157 gc/include/private/gc_pmark.h     register word _descr = (hhdr) -> hb_descr; \
_descr            159 gc/include/private/gc_pmark.h     if (_descr == 0) { \
_descr            168 gc/include/private/gc_pmark.h         mark_stack_top -> mse_descr = _descr; \