Messages in this thread | | | From | Nick Desaulniers <> | Date | Mon, 17 Sep 2018 10:24:11 -0700 | Subject | Re: [PATCH] ftrace: Build with CPPFLAGS to get -Qunused-arguments |
| |
On Mon, Sep 17, 2018 at 12:38 AM Joel Stanley <joel@jms.id.au> wrote: > > When building to record the mcount locations the kernel uses > KBUILD_CFLAGS but not KBUILD_CPPFLAGS. This means it lacks > -Qunused-arguments when building with clang, resulting in a lot of > noisy warnings. > > Signed-off-by: Joel Stanley <joel@jms.id.au> > --- > Not sure why -Qunused-arguments is in CPP instead of KBUILD_CFLAGS. We > could instead put it in KBUILD_CFLAGS, and not need this patch.
The preprocessor has flags that can change the definitions of macros. So there might be unused flags there. I'm not a fan of covering up those warnings via -Qunused-arguments; the flags should be feature detected via cc-option and friends rather than always added then silenced if excessive. That hides flags that are long dead/unused.
Thanks for this patch! Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> > scripts/Makefile.build | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 5a2d1c9578a0..54da4b070db3 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -219,7 +219,7 @@ else > sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ > "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ > "$(if $(CONFIG_64BIT),64,32)" \ > - "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \ > + "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \ > "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \ > "$(if $(part-of-module),1,0)" "$(@)"; > recordmcount_source := $(srctree)/scripts/recordmcount.pl > -- > 2.17.1 >
-- Thanks, ~Nick Desaulniers
| |