selftests: bpf: prepare for break up of verifier tests

test_verifier.c has grown to be very long (almost 16 kLoC),
and it is very conflict prone since we always add tests at
the end.

Try to break it apart a little bit. Allow test snippets
to be defined in separate files and include them automatically
into the huge test array.

Signed-off-by: Jakub Kicinski <[e-mail]>
Acked-by: Jiong Wang <[e-mail]>
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/testing/selftests/bpf/Makefile

···
 	$(BTF_PAHOLE) -J $@
 endif
 
+$(OUTPUT)/test_verifier: $(OUTPUT)/verifier/tests.h
+$(OUTPUT)/test_verifier: CFLAGS += -I$(OUTPUT)
+
+VERIFIER_TEST_FILES := $(wildcard verifier/*.c)
+$(OUTPUT)/verifier/tests.h: $(VERIFIER_TEST_FILES)
+	$(shell ( cd verifier/
+		  echo '/* Generated header, do not edit */'; \
+		  echo '#ifdef FILL_ARRAY'; \
+		  ls *.c 2> /dev/null | \
+			sed -e 's@\(.*\)@#include \"\1\"@'; \
+		  echo '#endif' \
+		 ) > $(OUTPUT)/verifier/tests.h)
+
 EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(ALU32_BUILD_DIR)

tools/testing/selftests/bpf/test_verifier.c

···
 	BPF_ALU64_IMM(BPF_ARSH, BPF_REG_7, 32)
 
 static struct bpf_test tests[] = {
+#define FILL_ARRAY
+#include <verifier/tests.h>
+#undef FILL_ARRAY
 	{
 		"add+sub+mul",
 		.insns = {

tools/testing/selftests/bpf/verifier/.gitignore

···
+tests.h