On Wed, Aug 28, 2019 at 11:19 PM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > On Wed, Aug 28, 2019 at 9:20 AM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > > > On Wed, Aug 28, 2019 at 7:55 AM Masahiro Yamada > > <yamada.masahiro@xxxxxxxxxxxxx> wrote: > > > > > > Instead of the warning-[123] magic, let's accumulate compiler options > > > to KBUILD_CFLAGS directly as the top Makefile does. I think this makes > > > easier to understand what is going on in this file. > > > > > > This commit slightly changes the behavior, I think all of which are OK. > > > > > > [1] Currently, cc-option calls are needlessly evaluated. For example, > > > warning-3 += $(call cc-option, -Wpacked-bitfield-compat) > > > needs evaluating only when W=3, but it is actually evaluated for > > > W=1, W=2 as well. With this commit, only relevant cc-option calls > > > will be evaluated. This is a slight optimization. > > > > > > [2] Currently, unsupported level like W=4 is checked by: > > > $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown) > > > This will no longer be checked, but I do not think it is a big > > > deal. > > > > > > > Hi Masahiro Yamada, > > > > thanks for your patch series. > > > > If KBUILD_ENABLE_EXTRA_GCC_CHECKS does extra(-warning)-checks for GCC and Clang, > > please rename the Kconfig into... You repeatedly mentioned "Kconfig" in your posts, where there is nothing related to Kconfig. > > > > KBUILD_ENABLE_EXTRA_CC_CHECKS You missed the fact this is already used not only for C compilers, but also for Device Tree compiler. (see scripts/Makefile.lib) One more thing, this is the environment variable that Kbuild officially supports. Keeping the backward compatibility is must. When I mentioned to rename this before, Arnd suggested to keep it as is. https://patchwork.kernel.org/patch/10172331/#21385013 I do not know whether he is still planning that rework, though. > > ...or something similiar (and maybe with some notes in its Kconfig help-text?). What did you mean by "Kconfig help-text" ? > > > > I have tested both patches against recent kbuild-next and can boot on > bare metal with clang. > > I have *not* passed any W= to my make, but I see that clang's W=1 > kbuild-cflags are active. > > [ scripts/Makefile.extrawarn ] > > ifeq ("$(origin W)", "command line") > export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W) > endif > > # > # W=1 - warnings that may be relevant and does not occur too often > # > ifneq ($(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)),) > [ ... ] > KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1 > > else > > # W=1 also stops suppressing some warnings > > ifdef CONFIG_CC_IS_CLANG > KBUILD_CFLAGS += -Wno-initializer-overrides > KBUILD_CFLAGS += -Wno-format > KBUILD_CFLAGS += -Wno-sign-compare > KBUILD_CFLAGS += -Wno-format-zero-length > endif # CONFIG_CC_IS_CLANG > > endif # KBUILD_ENABLE_EXTRA_GCC_CHECKS > > These clang KBUILD_CFLAGS are active independently of passing W=1. > > $ grep '\-Wno-initializer-overrides' > build-log_5.3.0-rc6-2-amd64-cbl-asmgoto.txt | wc -l > 27195 > > So the above comment is misleading? > > Is W=1 activated by default? > > Or do I miss something? I won't comment back to your long analysis. Instead, I will post v2. I hope you will notice something. > [ Documentation/kbuild/kbuild.rst ] > > KBUILD_ENABLE_EXTRA_GCC_CHECKS > ------------------------------ > If enabled over the make command line with "W=1", it turns on additional > gcc -W... options for more extensive build-time checking. > > What about? > > KBUILD_CC_EXTRA_CHECKS (or KBUILD_EXTRA_CC_CHECKS) > ------------------------------ > If enabled over the make command line with "W=...", it turns on additional > compiler warning options like -Wmissing-declarations for more extensive > build-time checking. For more details see <Documentation/kbuild/kbuild.rst>. > > W=1 - warnings that may be relevant and does not occur too often > W=1 - also stops suppressing some warnings > W=2 - warnings that occur quite often but may still be relevant > W=3 - the more obscure warnings, can most likely be ignored > > - Sedat - -- Best Regards Masahiro Yamada
