perf probe: Show accessible local variables

Add -V (--vars) option for listing accessible local variables at given probe
point. This will help finding which local variables are available for event
arguments.

e.g.)
 # perf probe -V call_timer_fn:23
 Available variables at call_timer_fn:23
         @<run_timer_softirq+345>
                 function_type*  fn
                 int     preempt_count
                 long unsigned int       data
                 struct list_head        work_list
                 struct list_head*       head
                 struct timer_list*      timer
                 struct tvec_base*       base

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101021101323.3542.40282.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 22 insertions, 3 deletions

diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 4507d519f183..baffd25f39c9 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -25,17 +25,22 @@ extern int find_probe_trace_events(int fd, struct perf_probe_event *pev,
 extern int find_perf_probe_point(int fd, unsigned long addr,
                                  struct perf_probe_point *ppt);
 
+/* Find a line range */
 extern int find_line_range(int fd, struct line_range *lr);
 
+/* Find available variables */
+extern int find_available_vars_at(int fd, struct perf_probe_event *pev,
+                                  struct variable_list **vls, int max_points);
+
 #include <dwarf.h>
 #include <libdw.h>
 #include <version.h>
 
 struct probe_finder {
         struct perf_probe_event *pev;           /* Target probe event */
-        struct probe_trace_event *tevs;         /* Result trace events */
-        int                     ntevs;          /* Number of trace events */
-        int                     max_tevs;       /* Max number of trace events */
+
+        /* Callback when a probe point is found */
+        int (*callback)(Dwarf_Die *sp_die, struct probe_finder *pf);
 
         /* For function searching */
         int                     lno;            /* Line number */
@@ -53,6 +58,20 @@ struct probe_finder {
         struct probe_trace_arg  *tvar;          /* Current result variable */
 };
 
+struct trace_event_finder {
+        struct probe_finder     pf;
+        struct probe_trace_event *tevs;         /* Found trace events */
+        int                     ntevs;          /* Number of trace events */
+        int                     max_tevs;       /* Max number of trace events */
+};
+
+struct available_var_finder {
+        struct probe_finder     pf;
+        struct variable_list    *vls;           /* Found variable lists */
+        int                     nvls;           /* Number of variable lists */
+        int                     max_vls;        /* Max no. of variable lists */
+};
+
 struct line_finder {
         struct line_range       *lr;            /* Target line range */