| Message ID | 20221012180118.331005-1-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/2] kbuild: move -Werror from KBUILD_CFLAGS to KBUILD_CPPFLAGS | expand |
On Thu, Oct 13, 2022 at 03:01:17AM +0900, Masahiro Yamada wrote: > CONFIG_WERROR turns warnings into errors, which happens only for *.c > files because -Werror is added to KBUILD_CFLAGS. > > Adding it to KBUILD_CPPFLAGS makes more sense because preprocessors > understand the -Werror option. > > For example, you can put a #warning directive in any preprocessed code. > > warning: #warning "this is a warning message" [-Wcpp] > > If -Werror is added, it is promoted to an error. > > error: #warning "this is a warning message" [-Werror=cpp] > > This commit moves -Werror to KBUILD_CPPFLAGS so it works in the same way > for *.c, *.S, *.lds.S or whatever needs preprocessing. > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > --- > > (no changes since v1) > > Makefile | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/Makefile b/Makefile > index 85a63a1d29b3..790760d26ea0 100644 > --- a/Makefile > +++ b/Makefile > @@ -859,7 +859,8 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong > > KBUILD_CFLAGS += $(stackp-flags-y) > > -KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror > +KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror > +KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y) > KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds > > KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings > -- > 2.34.1 > > For what it's worth, this is going to break 32-bit ARM builds with clang plus the integrated assembler due to https://github.com/ClangBuiltLinux/linux/issues/1315: clang-16: error: argument unused during compilation: '-march=armv7-a' [-Werror,-Wunused-command-line-argument] Ultimately, I want -Wunused-command-line-argument to be an error anyways (https://github.com/ClangBuiltLinux/linux/issues/1587) but it would be nice to get these cleaned up before this goes in. Cheers, Nathan
On Fri, Oct 14, 2022 at 9:03 AM Nathan Chancellor <nathan@kernel.org> wrote: > > On Thu, Oct 13, 2022 at 03:01:17AM +0900, Masahiro Yamada wrote: > > CONFIG_WERROR turns warnings into errors, which happens only for *.c > > files because -Werror is added to KBUILD_CFLAGS. > > > > Adding it to KBUILD_CPPFLAGS makes more sense because preprocessors > > understand the -Werror option. > > > For what it's worth, this is going to break 32-bit ARM builds with clang > plus the integrated assembler due to > https://github.com/ClangBuiltLinux/linux/issues/1315: > > clang-16: error: argument unused during compilation: '-march=armv7-a' [-Werror,-Wunused-command-line-argument] Ah, sorry, I should have finished off that series back then. I've rebased the series and sent a v4. https://lore.kernel.org/llvm/20221014201354.3190007-1-ndesaulniers@google.com/ You mentioned to me on IRC https://lore.kernel.org/linux-next/CAK7LNARg8OpqLR_71PJV3ZoLuDV8+mz9mphg=CzEeEEMY0G3rw@mail.gmail.com/ maybe will be a conflict. > > Ultimately, I want -Wunused-command-line-argument to be an error anyways > (https://github.com/ClangBuiltLinux/linux/issues/1587) but it would be > nice to get these cleaned up before this goes in. > > Cheers, > Nathan
On Sat, Oct 15, 2022 at 1:03 AM Nathan Chancellor <nathan@kernel.org> wrote: > > On Thu, Oct 13, 2022 at 03:01:17AM +0900, Masahiro Yamada wrote: > > CONFIG_WERROR turns warnings into errors, which happens only for *.c > > files because -Werror is added to KBUILD_CFLAGS. > > > > Adding it to KBUILD_CPPFLAGS makes more sense because preprocessors > > understand the -Werror option. > > > > For example, you can put a #warning directive in any preprocessed code. > > > > warning: #warning "this is a warning message" [-Wcpp] > > > > If -Werror is added, it is promoted to an error. > > > > error: #warning "this is a warning message" [-Werror=cpp] > > > > This commit moves -Werror to KBUILD_CPPFLAGS so it works in the same way > > for *.c, *.S, *.lds.S or whatever needs preprocessing. > > > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > --- > > > > (no changes since v1) > > > > Makefile | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/Makefile b/Makefile > > index 85a63a1d29b3..790760d26ea0 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -859,7 +859,8 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong > > > > KBUILD_CFLAGS += $(stackp-flags-y) > > > > -KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror > > +KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror > > +KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y) > > KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds > > > > KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings > > -- > > 2.34.1 > > > > > > For what it's worth, this is going to break 32-bit ARM builds with clang > plus the integrated assembler due to > https://github.com/ClangBuiltLinux/linux/issues/1315: > > clang-16: error: argument unused during compilation: '-march=armv7-a' [-Werror,-Wunused-command-line-argument] > > Ultimately, I want -Wunused-command-line-argument to be an error anyways > (https://github.com/ClangBuiltLinux/linux/issues/1587) but it would be > nice to get these cleaned up before this goes in. > > Cheers, > Nathan OK, I will postpone this patch. Thanks.
diff --git a/Makefile b/Makefile index 85a63a1d29b3..790760d26ea0 100644 --- a/Makefile +++ b/Makefile @@ -859,7 +859,8 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong KBUILD_CFLAGS += $(stackp-flags-y) -KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror +KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror +KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y) KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings
CONFIG_WERROR turns warnings into errors, which happens only for *.c files because -Werror is added to KBUILD_CFLAGS. Adding it to KBUILD_CPPFLAGS makes more sense because preprocessors understand the -Werror option. For example, you can put a #warning directive in any preprocessed code. warning: #warning "this is a warning message" [-Wcpp] If -Werror is added, it is promoted to an error. error: #warning "this is a warning message" [-Werror=cpp] This commit moves -Werror to KBUILD_CPPFLAGS so it works in the same way for *.c, *.S, *.lds.S or whatever needs preprocessing. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> --- (no changes since v1) Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)