First of all, in order to build with clang at all, one must first apply Valentin Obst's build fix for LLVM [1]. Once that is done, then when building with clang, via:

make LLVM=1 -C tools/testing/selftests

...the following error occurs:

clang: error: cannot specify -o when generating multiple output files

This is because clang, unlike gcc, won't accept invocations of this form:

clang file1.c header2.h

Fix this by using selftests/lib.mk facilities for tracking local header file dependencies: add them to LOCAL_HDRS, leaving only the .c files to be passed to the compiler.

[1] https://lore.kernel.org/all/20240329-selftests-libmk-llvm-rfc-v1-1-2f9ed7d1c...

Fixes: 8e289f454289 ("selftests/resctrl: Add resctrl.h into build deps") Cc: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Signed-off-by: John Hubbard jhubbard@nvidia.com --- tools/testing/selftests/resctrl/Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/resctrl/Makefile b/tools/testing/selftests/resctrl/Makefile index 2deac2031de9..021863f86053 100644 --- a/tools/testing/selftests/resctrl/Makefile +++ b/tools/testing/selftests/resctrl/Makefile @@ -5,6 +5,8 @@ CFLAGS += $(KHDR_INCLUDES)

TEST_GEN_PROGS := resctrl_tests

+LOCAL_HDRS += $(wildcard *.h) + include ../lib.mk

-$(OUTPUT)/resctrl_tests: $(wildcard *.[ch]) +$(OUTPUT)/resctrl_tests: $(wildcard *.c)

base-commit: f03359bca01bf4372cf2c118cd9a987a5951b1c8 prerequisite-patch-id: b901ece2a5b78503e2fb5480f20e304d36a0ea27