GC_STORE_BACK_PTR  263 gc/include/private/gc_pmark.h     GC_STORE_BACK_PTR((ptr_t)source, (ptr_t)HBLKPTR(current) \
GC_STORE_BACK_PTR 1392 gc/mark.c       	    GC_STORE_BACK_PTR(source, (ptr_t)r);