On Wed, Sep 7, 2022 at 1:59 PM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > as-instr uses KBUILD_AFLAGS, but as-option uses KBUILD_CFLAGS. This can > cause as-option to fail unexpectedly when CONFIG_WERROR is set, because > clang will emit -Werror,-Wunused-command-line-argument for various -m > and -f flags for assembler sources. > > Callers of as-option (and as-instr) likely want to be adding flags to > KBUILD_AFLAGS/aflags-y, not KBUILD_CFLAGS/cflags-y. > > Also, change as-option and as-instr to use -x assembler-with-cpp since > kernel sources are .S files that use the compiler as the driver. And > then add -Werror as well. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1699 > Suggested-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> > Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- 01 and 02, applied to linux-kbuild/fixes. Thanks. > Changes v2 -> v1: > * Add -x assembler-with-cpp -Werror to both as-option and (new) > as-instr, as per Masahiro. > * Add Masahiro's SB tag. > > Changes v1 -> v2: > * Split off changes to arch/x86/boot/compressed/Makefile into parent > patch, as per Masahiro. > > scripts/Makefile.compiler | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler > index 94d0d40cddb3..a66638b5f4a5 100644 > --- a/scripts/Makefile.compiler > +++ b/scripts/Makefile.compiler > @@ -29,16 +29,16 @@ try-run = $(shell set -e; \ > fi) > > # as-option > -# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) > +# Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,) > > as-option = $(call try-run,\ > - $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2)) > + $(CC) -Werror $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2)) > > # as-instr > -# Usage: cflags-y += $(call as-instr,instr,option1,option2) > +# Usage: aflags-y += $(call as-instr,instr,option1,option2) > > as-instr = $(call try-run,\ > - printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) > + printf "%b\n" "$(1)" | $(CC) -Werror $(KBUILD_AFLAGS) -c -x assembler-with-cpp -o "$$TMP" -,$(2),$(3)) > > # __cc-option > # Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586) > -- > 2.37.2.789.g6183377224-goog > -- Best Regards Masahiro Yamada
