[PATCH bpf-next v5 08/11] selftests/bpf: Tolerate benchmark build failures

[Ricardo B. Marlière]

Benchmark objects depend on skeletons that may be missing when some BPF
programs fail to build. In that case, benchmark object compilation or final
bench linking should not abort the full selftests/bpf build.

Keep both steps non-fatal, emit SKIP-BENCH or SKIP-LINK, and remove failed
outputs so stale objects or binaries are not reused by later incremental
builds. Note that because bench.c statically references every benchmark via
extern symbols, partial linking is not possible: if any single benchmark
object fails, the entire bench binary is skipped. This is by design -- the
error handler catches all compilation failures including genuine ones, but
those are caught by full-config CI runs.

Signed-off-by: Ricardo B. Marlière <rbm@xxxxxxxx>
---
 tools/testing/selftests/bpf/Makefile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 128ea61fd986..163552458327 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -891,7 +891,8 @@ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
 # Benchmark runner
 $(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(BPFOBJ)
 	$(call msg,CC,,$@)
-	$(Q)$(CC) $(CFLAGS) -O2 -c $(filter %.c,$^) $(LDLIBS) -o $@
+	$(Q)$(CC) $(CFLAGS) -O2 -c $(filter %.c,$^) $(LDLIBS) -o $@ $(if $(PERMISSIVE),|| \
+		($(RM) $@; printf '  %-12s %s\n' 'SKIP-BENCH' '$(notdir $@)' 1>&2))
 $(OUTPUT)/bench_rename.o: $(OUTPUT)/test_overhead.skel.h
 $(OUTPUT)/bench_trigger.o: $(OUTPUT)/trigger_bench.skel.h
 $(OUTPUT)/bench_ringbufs.o: $(OUTPUT)/ringbuf_bench.skel.h \
@@ -934,7 +935,8 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o \
 		 $(OUTPUT)/usdt_2.o \
 		 #
 	$(call msg,BINARY,,$@)
-	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@
+	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$(if $(PERMISSIVE),$(wildcard $^),$^)) $(LDLIBS) -o $@ $(if $(PERMISSIVE),|| \
+		($(RM) $@; printf '  %-12s %s\n' 'SKIP-LINK' '$(notdir $@) (some benchmarks may have been skipped)' 1>&2))
 
 # This works around GCC warning about snprintf truncating strings like:
 #

-- 
2.53.0