perf symbols: Consider unresolved DSOs in the dso__col_widt calculation

By using BITS_PER_LONG / 4, that is the number of chars that will be
used in such cases as the DSO "name".

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/event.c

@@ -676,6 +676,13 @@ int event__preprocess_sample(const event_t *self, struct perf_session *session,
 			dso__calc_col_width(al->map->dso);
 
 		al->sym = map__find_symbol(al->map, al->addr, filter);
+	} else {
+		const unsigned int unresolved_col_width = BITS_PER_LONG / 4;
+
+		if (dsos__col_width < unresolved_col_width &&
+		    !symbol_conf.col_width_list_str && !symbol_conf.field_sep &&
+		    !symbol_conf.dso_list)
+			dsos__col_width = unresolved_col_width;
 	}
 
 	if (symbol_conf.sym_list && al->sym &&