perf probe: Add data structure member access support

Support accessing members in the data structures. With this,
perf-probe accepts data-structure members(IOW, it now accepts
dot '.' and arrow '->' operators) as probe arguemnts.

e.g.

 ./perf probe --add 'schedule:44 rq->curr'

 ./perf probe --add 'vfs_read file->f_op->read file->f_path.dentry'

Note that '>' can be interpreted as redirection in command-line.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220626.32050.57552.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 11 insertions, 1 deletions

diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 2a2f0a26dc67..cd308b0a4d96 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -45,9 +45,17 @@ struct perf_probe_point {
         bool            retprobe;       /* Return probe flag */
 };
 
+/* Perf probe probing argument field chain */
+struct perf_probe_arg_field {
+        struct perf_probe_arg_field     *next;  /* Next field */
+        char                            *name;  /* Name of the field */
+        bool                            ref;    /* Referencing flag */
+};
+
 /* Perf probe probing argument */
 struct perf_probe_arg {
-        char            *name;          /* Argument name */
+        char                            *name;  /* Argument name */
+        struct perf_probe_arg_field     *field; /* Structure fields */
 };
 
 /* Perf probe probing event (point + arg) */
@@ -86,6 +94,8 @@ extern void parse_kprobe_trace_command(const char *cmd,
 /* Events to command string */
 extern char *synthesize_perf_probe_command(struct perf_probe_event *pev);
 extern char *synthesize_kprobe_trace_command(struct kprobe_trace_event *tev);
+extern int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf,
+                                     size_t len);
 
 /* Check the perf_probe_event needs debuginfo */
 extern bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);