From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
commit 91e2f539eeda26ab00bd03fae8dc434c128c85ed upstream.
Fix die_walk_lines() to list the function entry line correctly. Since
the dwarf_entrypc() does not return the entry pc if the DIE has only
range attribute, __die_walk_funclines() fails to list the declaration
line (entry line) in that case.
To solve this issue, this introduces die_entrypc() which correctly
returns the entry PC (the first address range) even if the DIE has only
range attribute. With this fix die_walk_lines() shows the function entry
line is able to probe correctly.
Fixes: 4cc9cec636e7 ("perf probe: Introduce lines walker interface")
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: http://lore.kernel.org/lkml/157190837419.1859.4619125803596816752.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Thomas Backlund <tmb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/util/dwarf-aux.c | 24 +++++++++++++++++++++++-
tools/perf/util/dwarf-aux.h | 3 +++
2 files changed, 26 insertions(+), 1 deletion(-)
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -318,6 +318,28 @@ bool die_is_func_def(Dwarf_Die *dw_die)
}
/**
+ * die_entrypc - Returns entry PC (the lowest address) of a DIE
+ * @dw_die: a DIE
+ * @addr: where to store entry PC
+ *
+ * Since dwarf_entrypc() does not return entry PC if the DIE has only address
+ * range, we have to use this to retrieve the lowest address from the address
+ * range attribute.
+ */
+int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
+{
+ Dwarf_Addr base, end;
+
+ if (!addr)
+ return -EINVAL;
+
+ if (dwarf_entrypc(dw_die, addr) == 0)
+ return 0;
+
+ return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
+}
+
+/**
* die_is_func_instance - Ensure that this DIE is an instance of a subprogram
* @dw_die: a DIE
*
@@ -730,7 +752,7 @@ static int __die_walk_funclines(Dwarf_Di
/* Handle function declaration line */
fname = dwarf_decl_file(sp_die);
if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
- dwarf_entrypc(sp_die, &addr) == 0) {
+ die_entrypc(sp_die, &addr) == 0) {
lw.retval = callback(fname, lineno, addr, data);
if (lw.retval != 0)
goto done;
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -41,6 +41,9 @@ int cu_walk_functions_at(Dwarf_Die *cu_d
/* Get DW_AT_linkage_name (should be NULL for C binary) */
const char *die_get_linkage_name(Dwarf_Die *dw_die);
+/* Get the lowest PC in DIE (including range list) */
+int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr);
+
/* Ensure that this DIE is a subprogram and definition (not declaration) */
bool die_is_func_def(Dwarf_Die *dw_die);
