selftests/bpf: Bring back c++ include/link test
Commit 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
converted existing c++ test to c. We still want to include and
link against libbpf from c++ code, so reinstate this test back,
this time in a form of a selftest with a clear comment about
its purpose.
v2:
* -lelf -> $(LDLIBS) (Andrii Nakryiko)
Fixes: 5c26f9a78358 ("libbpf: Don't use cxx to test_libpf target")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191202215931.248178-1-sdf@google.com
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 085678d..e0fe01d 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -71,7 +71,7 @@
# Compile but not part of 'make run_tests'
TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
- test_lirc_mode2_user xdping
+ test_lirc_mode2_user xdping test_cpp
TEST_CUSTOM_PROGS = urandom_read
@@ -317,6 +317,10 @@
$(OUTPUT)/test_verifier: test_verifier.c verifier/tests.h $(BPFOBJ) | $(OUTPUT)
$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
+# Make sure we are able to include and link libbpf against c++.
+$(OUTPUT)/test_cpp: test_cpp.cpp $(BPFOBJ)
+ $(CXX) $(CFLAGS) $^ $(LDLIBS) -o $@
+
EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) \
prog_tests/tests.h map_tests/tests.h verifier/tests.h \
feature $(OUTPUT)/*.o $(OUTPUT)/no_alu32 $(OUTPUT)/bpf_gcc