[PATCH 1/2] perf-probe: Fix to die_entrypc() returns error correctly

[Masami Hiramatsu]

Fix die_entrypc() to return error correctly if the DIE has no
DW_AT_ranges attribute. Since dwarf_ranges() will treat the case
as an empty ranges and return 0, we have to check it by ourselves.

Fixes: 91e2f539eeda ("perf probe: Fix to show function entry line as 
probe-able")
Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
---
 tools/perf/util/dwarf-aux.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index aa898014ad12..03c1a39c312a 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -373,6 +373,7 @@ bool die_is_func_def(Dwarf_Die *dw_die)
 int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
 {
        Dwarf_Addr base, end;
+       Dwarf_Attribute attr;
 
        if (!addr)
                return -EINVAL;
@@ -380,6 +381,13 @@ int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
        if (dwarf_entrypc(dw_die, addr) == 0)
                return 0;
 
+       /*
+        *  Since the dwarf_ranges() will return 0 if there is no
+        * DW_AT_ranges attribute, we should check it first.
+        */
+       if (!dwarf_attr(dw_die, DW_AT_ranges, &attr))
+               return -ENOENT;
+
        return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
 }