On Wed, Sep 7, 2022 at 12:12 PM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > > > > > > > > > I also believe '-x assembler' should be changed to > > '-x assembler-with-cpp'. > > > > > > As I mentioned somewhere before, our assembly code (*.S) is always > > preprocessed. There is no *.s file in the kernel source tree. > > > > > > So, '-x assembler-with-cpp' matches the real situation. > > Should I do this for as-instr then as well? In the same patch? Probably we should fix as-instr in the same way. You can do it in the same patch, or in a separate one. It is up to you. > > > > > > One interesting thing is, clang does not warn > > [-Wunused-command-line-argument] for *.S files. > > > > > > > > > > $ clang -fomit-frame-pointer -c -x assembler /dev/null -o /dev/null > > clang: warning: argument unused during compilation: > > '-fomit-frame-pointer' [-Wunused-command-line-argument] > > > > $ clang -fomit-frame-pointer -c -x assembler-with-cpp /dev/null -o /dev/null > > > > > > > > The root cause is we are using '-x assembler', which > > never happens in the kernel tree. > > > > > > > > > > To sum up, the code I think correct is: > > > > > > as-option = $(call try-run,\ > > $(CC) -Werror $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp > > /dev/null -o "$$TMP",$(1),$(2)) > > Does your recent patch affect this? > https://lore.kernel.org/linux-kbuild/20220905083619.672091-1-masahiroy@xxxxxxxxxx/ No, I do not think so. > If so, then I should not add -Werror as you suggest above? I think we should always add -Werror to as-option. as-option checks the command line options with /dev/null as the source input (that is, source input is always valid). If as-option results in a warning, that option will sprinkle the same warning for all *.S files in the source tree. So, any warning in as-option should be considered as an error. -- Best Regards Masahiro Yamada
