| Message ID | 20201026220331.3896226-2-arnd@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] Makefile.extrawarn: move -Wcast-align to W=3 | expand |
On Mon, Oct 26, 2020 at 11:03:14PM +0100, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > The -Wnested-externs warning has become useless with gcc, since > this warns every time that BUILD_BUG_ON() or similar macros > are used. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Also see: 2486baae2cf6 ("objtool: Allow nested externs to enable BUILD_BUG()") 6cf4ecf5c51d ("perf build: Allow nested externs to enable BUILD_BUG() usage") Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > scripts/Makefile.extrawarn | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn > index 6baee1200615..9406f752e355 100644 > --- a/scripts/Makefile.extrawarn > +++ b/scripts/Makefile.extrawarn > @@ -61,7 +61,10 @@ endif > ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),) > > KBUILD_CFLAGS += -Wdisabled-optimization > +ifdef CONFIG_CC_IS_CLANG > KBUILD_CFLAGS += -Wnested-externs > +endif > + > KBUILD_CFLAGS += -Wshadow > KBUILD_CFLAGS += $(call cc-option, -Wlogical-op) > KBUILD_CFLAGS += -Wmissing-field-initializers > -- > 2.27.0 >
On Mon, Oct 26, 2020 at 06:48:46PM -0700, Nathan Chancellor wrote: > On Mon, Oct 26, 2020 at 11:03:14PM +0100, Arnd Bergmann wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > > > The -Wnested-externs warning has become useless with gcc, since > > this warns every time that BUILD_BUG_ON() or similar macros > > are used. > > > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > > Also see: > > 2486baae2cf6 ("objtool: Allow nested externs to enable BUILD_BUG()") > 6cf4ecf5c51d ("perf build: Allow nested externs to enable BUILD_BUG() usage") > > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Actually, just delete this line altogether. -Wnested-externs is a GCC only warning, the flag is only present in clang for compatibility with GCC: https://clang.llvm.org/docs/DiagnosticsReference.html#wnested-externs With that, my reviewed by still stands. Cheers, Nathan
On Tue, Oct 27, 2020 at 1:32 PM Nathan Chancellor <natechancellor@gmail.com> wrote: > > On Mon, Oct 26, 2020 at 06:48:46PM -0700, Nathan Chancellor wrote: > > On Mon, Oct 26, 2020 at 11:03:14PM +0100, Arnd Bergmann wrote: > > > From: Arnd Bergmann <arnd@arndb.de> > > > > > > The -Wnested-externs warning has become useless with gcc, since > > > this warns every time that BUILD_BUG_ON() or similar macros > > > are used. > > > > > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > > > > Also see: > > > > 2486baae2cf6 ("objtool: Allow nested externs to enable BUILD_BUG()") > > 6cf4ecf5c51d ("perf build: Allow nested externs to enable BUILD_BUG() usage") > > > > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > > Actually, just delete this line altogether. -Wnested-externs is a GCC > only warning, the flag is only present in clang for compatibility with > GCC: > > https://clang.llvm.org/docs/DiagnosticsReference.html#wnested-externs > > With that, my reviewed by still stands. > I agree. Arnd, will you send v2? Please include https://clang.llvm.org/docs/DiagnosticsReference.html#wnested-externs as a reference. Thanks.
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 6baee1200615..9406f752e355 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -61,7 +61,10 @@ endif ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),) KBUILD_CFLAGS += -Wdisabled-optimization +ifdef CONFIG_CC_IS_CLANG KBUILD_CFLAGS += -Wnested-externs +endif + KBUILD_CFLAGS += -Wshadow KBUILD_CFLAGS += $(call cc-option, -Wlogical-op) KBUILD_CFLAGS += -Wmissing-field-initializers