On Fri, Jul 26, 2019 at 2:21 PM Stanislav Fomichev [off-list ref] wrote:

On 07/26, Andrii Nakryiko wrote:

quoted

Apprently listing header as a normal dependency for a binary output
makes it go through compilation as if it was C code. This currently
works without a problem, but in subsequent commits causes problems for
differently generated test.h for test_progs. Marking those headers as
order-only dependency solves the issue.

Are you sure it will not result in a situation where
test_progs/test_maps is not regenerated if tests.h is updated.

If I read the following doc correctly, order deps make sense for
directories only:
https://www.gnu.org/software/make/manual/html_node/Prerequisite-Types.html

Can you maybe double check it with:
* make
* add new prog_tests/test_something.c
* make
to see if the binary is regenerated with test_something.c?

Yeah, tested that, it triggers test_progs rebuild.

Ordering is still preserved, because test.h is dependency of
test_progs.c, which is dependency of test_progs binary, so that's why
it works.

As to why .h file is compiled as C file, I have no idea and ideally
that should be fixed somehow.

I also started with just removing header as dependency completely
(because it's indirect dependency of test_progs.c), but that broke the
build logic. Dunno, too much magic... This works, tested many-many
times, so I was satisfied enough :)

Maybe fix the problem of header compilation by having '#ifndef
DECLARE_TEST #define DECLARE_TEST() #endif' in tests.h instead?

That's ugly, I'd like to avoid doing that.

quoted

Signed-off-by: Andrii Nakryiko <redacted>
---
 tools/testing/selftests/bpf/Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 11c9c62c3362..bb66cc4a7f34 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile

@@ -235,7 +235,7 @@ PROG_TESTS_H := $(PROG_TESTS_DIR)/tests.h
 PROG_TESTS_FILES := $(wildcard prog_tests/*.c)
 test_progs.c: $(PROG_TESTS_H)
 $(OUTPUT)/test_progs: CFLAGS += $(TEST_PROGS_CFLAGS)
-$(OUTPUT)/test_progs: test_progs.c $(PROG_TESTS_H) $(PROG_TESTS_FILES)
+$(OUTPUT)/test_progs: test_progs.c $(PROG_TESTS_FILES) | $(PROG_TESTS_H)
 $(PROG_TESTS_H): $(PROG_TESTS_FILES) | $(PROG_TESTS_DIR)
      $(shell ( cd prog_tests/; \
                echo '/* Generated header, do not edit */'; \

@@ -256,7 +256,7 @@ MAP_TESTS_H := $(MAP_TESTS_DIR)/tests.h
 MAP_TESTS_FILES := $(wildcard map_tests/*.c)
 test_maps.c: $(MAP_TESTS_H)
 $(OUTPUT)/test_maps: CFLAGS += $(TEST_MAPS_CFLAGS)
-$(OUTPUT)/test_maps: test_maps.c $(MAP_TESTS_H) $(MAP_TESTS_FILES)
+$(OUTPUT)/test_maps: test_maps.c $(MAP_TESTS_FILES) | $(MAP_TESTS_H)
 $(MAP_TESTS_H): $(MAP_TESTS_FILES) | $(MAP_TESTS_DIR)
      $(shell ( cd map_tests/; \
                echo '/* Generated header, do not edit */'; \

@@ -277,7 +277,7 @@ VERIFIER_TESTS_H := $(VERIFIER_TESTS_DIR)/tests.h
 VERIFIER_TEST_FILES := $(wildcard verifier/*.c)
 test_verifier.c: $(VERIFIER_TESTS_H)
 $(OUTPUT)/test_verifier: CFLAGS += $(TEST_VERIFIER_CFLAGS)
-$(OUTPUT)/test_verifier: test_verifier.c $(VERIFIER_TESTS_H)
+$(OUTPUT)/test_verifier: test_verifier.c | $(VERIFIER_TEST_FILES) $(VERIFIER_TESTS_H)
 $(VERIFIER_TESTS_H): $(VERIFIER_TEST_FILES) | $(VERIFIER_TESTS_DIR)
      $(shell ( cd verifier/; \
                echo '/* Generated header, do not edit */'; \
--

2.17.1