[PATCH 14/16] perf probe: Improve error message when %return is on inlined function

From: Arnaldo Carvalho de Melo
Date: Wed Sep 30 2015 - 17:56:00 EST


From: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>

perf probe shows more precisely message when it finds given
%return target function is inlined.

Without this fix:
----
# ./perf probe -V getname_flags%return
Return probe must be on the head of a real function.
Debuginfo analysis failed.
Error: Failed to show vars.
----

With this fix:
----
# ./perf probe -V getname_flags%return
Failed to find "getname_flags%return",
because getname_flags is an inlined function and has no return point.
Debuginfo analysis failed.
Error: Failed to show vars.
----

Suggested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20150930164137.3733.55055.stgit@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/probe-finder.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index f0708ffd5e07..bd8f03de5e40 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -594,6 +594,7 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
/* Convert subprogram DIE to trace point */
static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
Dwarf_Addr paddr, bool retprobe,
+ const char *function,
struct probe_trace_point *tp)
{
Dwarf_Addr eaddr, highaddr;
@@ -637,8 +638,10 @@ static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
/* Return probe must be on the head of a subprogram */
if (retprobe) {
if (eaddr != paddr) {
- pr_warning("Return probe must be on the head of"
- " a real function.\n");
+ pr_warning("Failed to find \"%s%%return\",\n"
+ " because %s is an inlined function and"
+ " has no return point.\n", function,
+ function);
return -EINVAL;
}
tp->retprobe = true;
@@ -1178,6 +1181,7 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
{
struct trace_event_finder *tf =
container_of(pf, struct trace_event_finder, pf);
+ struct perf_probe_point *pp = &pf->pev->point;
struct probe_trace_event *tev;
struct perf_probe_arg *args;
int ret, i;
@@ -1192,7 +1196,7 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)

/* Trace point should be converted from subprogram DIE */
ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
- pf->pev->point.retprobe, &tev->point);
+ pp->retprobe, pp->function, &tev->point);
if (ret < 0)
return ret;

@@ -1322,6 +1326,7 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
{
struct available_var_finder *af =
container_of(pf, struct available_var_finder, pf);
+ struct perf_probe_point *pp = &pf->pev->point;
struct variable_list *vl;
Dwarf_Die die_mem;
int ret;
@@ -1335,7 +1340,7 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)

/* Trace point should be converted from subprogram DIE */
ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
- pf->pev->point.retprobe, &vl->point);
+ pp->retprobe, pp->function, &vl->point);
if (ret < 0)
return ret;

--
2.1.0

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