perf tools: Add the bash completion for listing subsubcommands of perf help

The bash completion does not support listing subsubcommands for 'perf
help <TAB>', so fix it.

Example:

Before this patch:

 $ perf help <TAB>
 $

As shown above, the subsubcommands of perf help does not come out.

After this patch:

 $ perf help <TAB>
 annotate       buildid-cache  data           evlist         inject
 kvm            lock           probe          report         script
 test           top
 bench          buildid-list   diff           help           kmem
 list           mem            record         sched          stat
 timechart      trace

As shown above, the subsubcommands of perf help can come out now.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1426685758-25488-9-git-send-email-yunlong.song@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 15 insertions, 4 deletions

diff --git a/tools/perf/builtin-help.c b/tools/perf/builtin-help.c
index 25d20628212e..36486eade1ef 100644
--- a/tools/perf/builtin-help.c
+++ b/tools/perf/builtin-help.c
@@ -437,7 +437,18 @@ int cmd_help(int argc, const char **argv, const char *prefix __maybe_unused)
                         HELP_FORMAT_INFO),
         OPT_END(),
         };
-        const char * const builtin_help_usage[] = {
+        const char * const builtin_help_subcommands[] = {
+                "buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
+                "record", "report", "bench", "stat", "timechart", "top", "annotate",
+                "script", "sched", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
+#ifdef HAVE_LIBELF_SUPPORT
+                "probe",
+#endif
+#ifdef HAVE_LIBAUDIT_SUPPORT
+                "trace",
+#endif
+        NULL };
+        const char *builtin_help_usage[] = {
                 "perf help [--all] [--man|--web|--info] [command]",
                 NULL
         };
@@ -448,8 +459,8 @@ int cmd_help(int argc, const char **argv, const char *prefix __maybe_unused)
 
         perf_config(perf_help_config, &help_format);
 
-        argc = parse_options(argc, argv, builtin_help_options,
-                        builtin_help_usage, 0);
+        argc = parse_options_subcommand(argc, argv, builtin_help_options,
+                        builtin_help_subcommands, builtin_help_usage, 0);
 
         if (show_all) {
                 printf("\n usage: %s\n\n", perf_usage_string);
diff --git a/tools/perf/perf-completion.sh b/tools/perf/perf-completion.sh
index 535ff72babc7..dbca6a66f401 100644
--- a/tools/perf/perf-completion.sh
+++ b/tools/perf/perf-completion.sh
@@ -143,7 +143,7 @@ __perf_main ()
                 __perfcomp_colon "$evts" "$cur"
         else
                 # List subcommands for perf commands
-                if [[ $prev_skip_opts == @(kvm|kmem|mem|lock|sched|data) ]]; then
+                if [[ $prev_skip_opts == @(kvm|kmem|mem|lock|sched|data|help) ]]; then
                         subcmds=$($cmd $prev_skip_opts --list-cmds)
                         __perfcomp_colon "$subcmds" "$cur"
                 fi