[PATCH 3/5] perf-probe: Add __return suffix for return events

[Masami Hiramatsu]

Add __return suffix for function return events
automatically. Without this, user have to give --force
option and will see the number suffix for each event
like "function_1", which is not easy to recognize.
Instead, this adds __return suffix to it automatically.
E.g.

  =====
  # ./perf probe -x /lib64/libc-2.25.so 'malloc*%return'
  Added new events:
    probe_libc:malloc_printerr__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc_consolidate__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc_check__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc_hook_ini__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_trim__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc_usable_size__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc_stats__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc_info__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:mallochook__return (on malloc*%return in /usr/lib64/libc-2.25.so)
    probe_libc:malloc_get_state__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)
    probe_libc:malloc_set_state__return (on malloc*%return in 
/usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

          perf record -e probe_libc:malloc_set_state__return -aR sleep 1

  =====

Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
Reported-by: Arnaldo Carvalho de Melo <a...@kernel.org>
---
 tools/perf/util/probe-event.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 74435fb7ab7f..959c4d2ef455 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2573,7 +2573,8 @@ int show_perf_probe_events(struct strfilter *filter)
 }
 
 static int get_new_event_name(char *buf, size_t len, const char *base,
-                             struct strlist *namelist, bool allow_suffix)
+                             struct strlist *namelist, bool ret_event,
+                             bool allow_suffix)
 {
        int i, ret;
        char *p, *nbase;
@@ -2590,7 +2591,7 @@ static int get_new_event_name(char *buf, size_t len, 
const char *base,
                *p = '\0';
 
        /* Try no suffix number */
-       ret = e_snprintf(buf, len, "%s", nbase);
+       ret = e_snprintf(buf, len, "%s%s", nbase, ret_event ? "__return" : "");
        if (ret < 0) {
                pr_debug("snprintf() failed: %d\n", ret);
                goto out;
@@ -2689,8 +2690,8 @@ static int probe_trace_event__set_name(struct 
probe_trace_event *tev,
                group = PERFPROBE_GROUP;
 
        /* Get an unused new event name */
-       ret = get_new_event_name(buf, 64, event,
-                                namelist, allow_suffix);
+       ret = get_new_event_name(buf, 64, event, namelist,
+                                tev->point.retprobe, allow_suffix);
        if (ret < 0)
                return ret;