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

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

Example:

Before this patch:

 $ perf script <TAB>
 $

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

After this patch:

 $ perf script <TAB>
 record  report

As shown above, the subsubcommands of perf script 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/1426685758-25488-10-git-send-email-yunlong.song@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-script.c

@@ -1572,7 +1572,8 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
 		    "Show the mmap events"),
 	OPT_END()
 	};
-	const char * const script_usage[] = {
+	const char * const script_subcommands[] = { "record", "report", NULL };
+	const char *script_usage[] = {
 		"perf script [<options>]",
 		"perf script [<options>] record <script> [<record-options>] <command>",
 		"perf script [<options>] report <script> [script-args]",
@@ -1586,7 +1587,7 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
 
 	setup_scripting();
 
-	argc = parse_options(argc, argv, options, script_usage,
+	argc = parse_options_subcommand(argc, argv, options, script_subcommands, script_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
 
 	file.path = input_name;

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|help) ]]; then
+		if [[ $prev_skip_opts == @(kvm|kmem|mem|lock|sched|data|help|script) ]]; then
 			subcmds=$($cmd $prev_skip_opts --list-cmds)
 			__perfcomp_colon "$subcmds" "$cur"
 		fi