perf bpf: Fix build with libbpf 0.7.0 by checking if bpf_program__set_insns() is available

During the transition to libbpf 1.0 some functions that perf used were
deprecated and finally removed from libbpf, so bpf_program__set_insns()
was introduced for perf to continue to use its bpf loader.

But when build with LIBBPF_DYNAMIC=1 we now need to check if that
function is available so that perf can build with older libbpf versions,
even if the end result is emitting a warning to the user that the use
of the perf BPF loader requires a newer libbpf, since bpf_program__set_insns()
touches libbpf objects internal state.

This affects only 'perf trace' when using bpf C code or pre-compiled
bytecode as an event.

Noticed on RHEL9, that has libbpf 0.7.0, where bpf_program__set_insns()
isn't available.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 13 insertions, 0 deletions

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 57619f240b56..38f8851bd7cb 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -103,6 +103,7 @@ FEATURE_TESTS_EXTRA :=                  \
          libbpf-bpf_prog_load           \
          libbpf-bpf_object__next_program \
          libbpf-bpf_object__next_map    \
+         libbpf-bpf_program__set_insns  \
          libbpf-bpf_create_map		\
          libpfm4                        \
          libdebuginfod			\
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 04b07ff88234..690fe97be190 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -63,6 +63,7 @@ FILES=                                          \
          test-libbpf-bpf_map_create.bin		\
          test-libbpf-bpf_object__next_program.bin \
          test-libbpf-bpf_object__next_map.bin   \
+         test-libbpf-bpf_program__set_insns.bin	\
          test-libbpf-btf__raw_data.bin          \
          test-get_cpuid.bin                     \
          test-sdt.bin                           \
@@ -316,6 +317,9 @@ $(OUTPUT)test-libbpf-bpf_object__next_program.bin:
 $(OUTPUT)test-libbpf-bpf_object__next_map.bin:
 	$(BUILD) -lbpf
 
+$(OUTPUT)test-libbpf-bpf_program__set_insns.bin:
+	$(BUILD) -lbpf
+
 $(OUTPUT)test-libbpf-btf__raw_data.bin:
 	$(BUILD) -lbpf
 
diff --git a/tools/build/feature/test-libbpf-bpf_program__set_insns.c b/tools/build/feature/test-libbpf-bpf_program__set_insns.c
new file mode 100644
index 000000000000..f3b7f18c8f49
--- /dev/null
+++ b/tools/build/feature/test-libbpf-bpf_program__set_insns.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <bpf/libbpf.h>
+
+int main(void)
+{
+	bpf_program__set_insns(NULL /* prog */, NULL /* new_insns */, 0 /* new_insn_cnt */);
+	return 0;
+}