[PATCH v5 5/9] perf libdw: Support DWARF line 0 in inline list

[Ian Rogers <irogers@google.com>]

Allow DWARF line 0 in `libdw_a2l_cb()`, as it is a valid
reference for compiler-generated code.

Filter `die_get_call_lineno` error codes (negative values), but
fallback to line 0 if `call_fname` is present to preserve the
caller's filename instead of discarding it entirely.

Signed-off-by: Ian Rogers <irogers@google.com>
---
v5:
 - Split from original Patch 3/6 into its own commit.
 - Fixed fallback logic for missing call lines to preserve filename by defaulting to line 0.
---
 tools/perf/util/libdw.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/libdw.c b/tools/perf/util/libdw.c
index 301642084c69..196b9cdf51b2 100644
--- a/tools/perf/util/libdw.c
+++ b/tools/perf/util/libdw.c
@@ -80,6 +80,7 @@ static int libdw_a2l_cb(Dwarf_Die *die, void *_args)
 	struct libdw_a2l_cb_args *args  = _args;
 	struct symbol *inline_sym = new_inline_sym(args->dso, args->sym, dwarf_diename(die));
 	const char *call_fname = die_get_call_file(die);
+	int call_lineno = die_get_call_lineno(die);
 	char *call_srcline = srcline__unknown;
 
 	if (!inline_sym)
@@ -87,7 +88,7 @@ static int libdw_a2l_cb(Dwarf_Die *die, void *_args)
 
 	/* Assign caller information to the parent. */
 	if (call_fname)
-		call_srcline = srcline_from_fileline(call_fname, die_get_call_lineno(die));
+		call_srcline = srcline_from_fileline(call_fname, call_lineno >= 0 ? call_lineno : 0);
 
 	if (!list_empty(&args->node->val)) {
 		struct inline_list *parent;
-- 
2.54.0.545.g6539524ca2-goog