[PATCH 4/8] perf callchain: Use debug_frame if eh_frame is unusable

From: Arnaldo Carvalho de Melo
Date: Tue Oct 13 2015 - 15:42:01 EST


From: Rabin Vincent <rabin.vincent@xxxxxxxx>

When NO_LIBUNWIND_DEBUG_FRAME=0, use the .debug_frame if the .eh_frame
doesn't contain the approprate unwind tables.

Signed-off-by: Rabin Vincent <rabin.vincent@xxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Rabin Vincent <rabinv@xxxxxxxx>
Link: http://lkml.kernel.org/r/1443379079-29133-3-git-send-email-rabin.vincent@xxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/unwind-libunwind.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index 4c00507ee3fd..ea993f6c7e0c 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -330,6 +330,7 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
struct map *map;
unw_dyn_info_t di;
u64 table_data, segbase, fde_count;
+ int ret = -EINVAL;

map = find_map(ip, ui);
if (!map || !map->dso)
@@ -348,13 +349,14 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
di.u.rti.table_data = map->start + table_data;
di.u.rti.table_len = fde_count * sizeof(struct table_entry)
/ sizeof(unw_word_t);
- return dwarf_search_unwind_table(as, ip, &di, pi,
- need_unwind_info, arg);
+ ret = dwarf_search_unwind_table(as, ip, &di, pi,
+ need_unwind_info, arg);
}

#ifndef NO_LIBUNWIND_DEBUG_FRAME
/* Check the .debug_frame section for unwinding info */
- if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
+ if (ret < 0 &&
+ !read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
int fd = dso__data_get_fd(map->dso, ui->machine);
int is_exec = elf_is_exec(fd, map->dso->name);
unw_word_t base = is_exec ? 0 : map->start;
@@ -370,7 +372,7 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
}
#endif

- return -EINVAL;
+ return ret;
}

static int access_fpreg(unw_addr_space_t __maybe_unused as,
--
2.1.0

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