perf probe: Support --line option to show probable source-code lines

Add --line option to support showing probable source-code lines.

  perf probe --line SRC:LN[-LN|+NUM]
   or
  perf probe --line FUNC[:LN[-LN|+NUM]]

This option shows source-code with line number if the line can
be probed. Lines without line number (and blue color) means that
the line can not be probed, because debuginfo doesn't have the
information of those lines.

The argument specifies the range of lines, "source.c:100-120"
shows lines between 100th to l20th in source.c file. And
"func:10+20" shows 20 lines from 10th line of func function.

e.g.
 # ./perf probe --line kernel/sched.c:1080
 <kernel/sched.c:1080>
          *
          * called with rq->lock held and irqs disabled
          */
         static void hrtick_start(struct rq *rq, u64 delay)
         {
                struct hrtimer *timer = &rq->hrtick_timer;
   1086         ktime_t time = ktime_add_ns(timer->base->get_time(), delay);

                hrtimer_set_expires(timer, time);

   1090         if (rq == this_rq()) {
   1091                 hrtimer_restart(timer);
   1092         } else if (!rq->hrtick_csd_pending) {
   1093                 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd,
   1094                 rq->hrtick_csd_pending = 1;

If you specifying function name, this shows function-relative
line number.

 # ./perf probe --line schedule
 <schedule:0>
         asmlinkage void __sched schedule(void)
      1  {
                struct task_struct *prev, *next;
                unsigned long *switch_count;
                struct rq *rq;
                int cpu;

         need_resched:
                preempt_disable();
      9         cpu = smp_processor_id();
     10         rq = cpu_rq(cpu);
     11         rcu_sched_qs(cpu);
     12         prev = rq->curr;
     13         switch_count = &prev->nivcsw;

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20100106144534.27218.77939.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 63 insertions, 13 deletions

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index ffdd3fe87b4..1d3a99ea5ce 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -55,11 +55,13 @@ static struct {
 	bool need_dwarf;
 	bool list_events;
 	bool force_add;
+	bool show_lines;
 	int nr_probe;
 	struct probe_point probes[MAX_PROBES];
 	struct strlist *dellist;
 	struct perf_session *psession;
 	struct map *kmap;
+	struct line_range line_range;
 } session;
 
 
@@ -116,6 +118,15 @@ static int opt_del_probe_event(const struct option *opt __used,
 	return 0;
 }
 
+static int opt_show_lines(const struct option *opt __used,
+			  const char *str, int unset __used)
+{
+	if (str)
+		parse_line_range_desc(str, &session.line_range);
+	INIT_LIST_HEAD(&session.line_range.line_list);
+	session.show_lines = true;
+	return 0;
+}
 /* Currently just checking function name from symbol map */
 static void evaluate_probe_point(struct probe_point *pp)
 {
@@ -144,6 +155,7 @@ static const char * const probe_usage[] = {
 	"perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
 	"perf probe [<options>] --del '[GROUP:]EVENT' ...",
 	"perf probe --list",
+	"perf probe --line 'LINEDESC'",
 	NULL
 };
 
@@ -182,9 +194,32 @@ static const struct option options[] = {
 		opt_add_probe_event),
 	OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
 		    " with existing name"),
+#ifndef NO_LIBDWARF
+	OPT_CALLBACK('L', "line", NULL,
+		     "FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]",
+		     "Show source code lines.", opt_show_lines),
+#endif
 	OPT_END()
 };
 
+/* Initialize symbol maps for vmlinux */
+static void init_vmlinux(void)
+{
+	symbol_conf.sort_by_name = true;
+	if (symbol_conf.vmlinux_name == NULL)
+		symbol_conf.try_vmlinux_path = true;
+	else
+		pr_debug("Use vmlinux: %s\n", symbol_conf.vmlinux_name);
+	if (symbol__init() < 0)
+		die("Failed to init symbol map.");
+	session.psession = perf_session__new(NULL, O_WRONLY, false);
+	if (session.psession == NULL)
+		die("Failed to init perf_session.");
+	session.kmap = session.psession->vmlinux_maps[MAP__FUNCTION];
+	if (!session.kmap)
+		die("Could not find kernel map.\n");
+}
+
 int cmd_probe(int argc, const char **argv, const char *prefix __used)
 {
 	int i, ret;
@@ -203,7 +238,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 		parse_probe_event_argv(argc, argv);
 	}
 
-	if ((!session.nr_probe && !session.dellist && !session.list_events))
+	if ((!session.nr_probe && !session.dellist && !session.list_events &&
+	     !session.show_lines))
 		usage_with_options(probe_usage, options);
 
 	if (debugfs_valid_mountpoint(debugfs_path) < 0)
@@ -215,10 +251,34 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 				   " --add/--del.\n");
 			usage_with_options(probe_usage, options);
 		}
+		if (session.show_lines) {
+			pr_warning("  Error: Don't use --list with --line.\n");
+			usage_with_options(probe_usage, options);
+		}
 		show_perf_probe_events();
 		return 0;
 	}
 
+#ifndef NO_LIBDWARF
+	if (session.show_lines) {
+		if (session.nr_probe != 0 || session.dellist) {
+			pr_warning("  Error: Don't use --line with"
+				   " --add/--del.\n");
+			usage_with_options(probe_usage, options);
+		}
+		init_vmlinux();
+		fd = open_vmlinux();
+		if (fd < 0)
+			die("Could not open debuginfo file.");
+		ret = find_line_range(fd, &session.line_range);
+		if (ret <= 0)
+			die("Source line is not found.\n");
+		close(fd);
+		show_line_range(&session.line_range);
+		return 0;
+	}
+#endif
+
 	if (session.dellist) {
 		del_trace_kprobe_events(session.dellist);
 		strlist__delete(session.dellist);
@@ -226,18 +286,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 			return 0;
 	}
 
-	/* Initialize symbol maps for vmlinux */
-	symbol_conf.sort_by_name = true;
-	if (symbol_conf.vmlinux_name == NULL)
-		symbol_conf.try_vmlinux_path = true;
-	if (symbol__init() < 0)
-		die("Failed to init symbol map.");
-	session.psession = perf_session__new(NULL, O_WRONLY, false);
-	if (session.psession == NULL)
-		die("Failed to init perf_session.");
-	session.kmap = session.psession->vmlinux_maps[MAP__FUNCTION];
-	if (!session.kmap)
-		die("Could not find kernel map.\n");
+	/* Add probes */
+	init_vmlinux();
 
 	if (session.need_dwarf)
 #ifdef NO_LIBDWARF