[PATCH v3 3/3] perf probe: Show better error message when failed to find variable

He Kuang
2015-05-11T09:26:01Z

Indicate to check variable location range in error message when we got
failed to find the variable.

Before this patch:

$ perf probe --add 'generic_perform_write+118 bytes'
Failed to find the location of bytes at this address.
Perhaps, it has been optimized out.
Error: Failed to add events.

After this patch:
$ perf probe --add 'generic_perform_write+118 bytes'
Failed to find the location of bytes at this address.
Perhaps, it has been optimized out.
Use -V with --range option to show variable location range.
Error: Failed to add events.

Signed-off-by: He Kuang <hekuang@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
tools/perf/util/probe-finder.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index f032329..8510cde 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -529,7 +529,9 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
&pf->sp_die, pf->tvar);
if (ret == -ENOENT || ret == -EINVAL)
pr_err("Failed to find the location of %s at this address.\n"
- " Perhaps, it has been optimized out.\n", pf->pvar->var);
+ " Perhaps, it has been optimized out.\n"
+ " Use -V with --range option to show variable location range.\n",
+ pf->pvar->var);
else if (ret == -ENOTSUP)
pr_err("Sorry, we don't support this variable location yet.\n");
else if (ret == 0 && pf->pvar->field) {
--
1.8.5.2