With clang compiler: make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1 the test_cpp build failed due to the failure: warning: treating 'c-header' input as 'c++-header' when in C++ mode, this behavior is deprecated [-Wdeprecated] clang-13: error: cannot specify -o when generating multiple output files test_cpp compilation flag looks like: clang++ -g -Og -rdynamic -Wall -I<...> ... \ -Dbpf_prog_load=bpf_prog_test_load -Dbpf_load_program=bpf_test_load_program \ test_cpp.cpp <...>/test_core_extern.skel.h <...>/libbpf.a <...>/test_stub.o \ -lcap -lelf -lz -lrt -lpthread -o <...>/test_cpp The clang++ compiler complains the header file in the command line and also failed the compilation due to this. Let us remove the header file from the command line which is not intended any way, and this fixed the compilation problem. Signed-off-by: Yonghong Song <yhs@xxxxxx> --- tools/testing/selftests/bpf/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 6448c626498f..dcc2dc1f2a86 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -481,7 +481,7 @@ $(OUTPUT)/test_verifier: test_verifier.c verifier/tests.h $(BPFOBJ) | $(OUTPUT) # Make sure we are able to include and link libbpf against c++. $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ) $(call msg,CXX,,$@) - $(Q)$(CXX) $(CFLAGS) $^ $(LDLIBS) -o $@ + $(Q)$(CXX) $(CFLAGS) $(filter %.a %.o %.cpp,$^) $(LDLIBS) -o $@ # Benchmark runner $(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h -- 2.30.2
