[PATCH v1 3/4] perf header: Display message if BPF/BTF info is empty

[Ian Rogers <irogers@google.com>]

The perf.data file may contain a bpf_prog_info or bpf_btf feature. If
the contents of these are empty then nothing is displayed. Rather than
display nothing and not account for the file space, display an empty
message.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/header.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 7798435ab5d3..69e4f6aae293 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1814,6 +1814,9 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
 	root = &env->bpf_progs.infos;
 	next = rb_first(root);
 
+	if (!next)
+		printf("# bpf_prog_info empty\n");
+
 	while (next) {
 		struct bpf_prog_info_node *node;
 
@@ -1838,6 +1841,9 @@ static void print_bpf_btf(struct feat_fd *ff, FILE *fp)
 	root = &env->bpf_progs.btfs;
 	next = rb_first(root);
 
+	if (!next)
+		printf("# btf info empty\n");
+
 	while (next) {
 		struct btf_node *node;
 
-- 
2.50.0.rc0.604.gd4ff7b7c86-goog