On Mon, Aug 07, 2023 at 09:50:32AM -0700, Nick Desaulniers wrote:
> I noticed Tom was sending patches where smatch was recommending
> annotating functions as static when no previous declaration existed.
> Surely the compiler could make such recommendations as well, I thought.
>
> Looks like -Wmissing-variable-declarations can make such
> recommendations.
>
> GCC just added support for this warning (gcc 14.1.0 will ship with
> support), and all versions of clang relevant to building the kernel
> support this flag.
>
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Any idea how many instances of this there are? At least x86_64 defconfig
fails immediately with:
In file included from scripts/mod/devicetable-offsets.c:3:
In file included from include/linux/mod_devicetable.h:14:
In file included from include/linux/uuid.h:11:
In file included from include/linux/string.h:20:
In file included from arch/x86/include/asm/string.h:5:
In file included from arch/x86/include/asm/string_64.h:6:
In file included from include/linux/jump_label.h:112:
In file included from arch/x86/include/asm/jump_label.h:7:
arch/x86/include/asm/asm.h:208:24: error: no previous extern declaration for non-static variable 'current_stack_pointer' [-Werror,-Wmissing-variable-declarations]
208 | register unsigned long current_stack_pointer asm(_ASM_SP);
| ^
arch/x86/include/asm/asm.h:208:10: note: declare 'static' if the variable is not intended to be used outside of this translation unit
208 | register unsigned long current_stack_pointer asm(_ASM_SP);
| ^
1 error generated.
> ---
> scripts/Makefile.extrawarn | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
> index 40cd13eca82e..617739eb84e2 100644
> --- a/scripts/Makefile.extrawarn
> +++ b/scripts/Makefile.extrawarn
> @@ -32,6 +32,7 @@ KBUILD_CFLAGS += $(call cc-option, -Wunused-but-set-variable)
> KBUILD_CFLAGS += $(call cc-option, -Wunused-const-variable)
> KBUILD_CFLAGS += $(call cc-option, -Wpacked-not-aligned)
> KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation)
> +KBUILD_CFLAGS += $(call cc-option, -Wmissing-varibale-declarations)
^ variable
> # The following turn off the warnings enabled by -Wextra
> KBUILD_CFLAGS += -Wno-missing-field-initializers
> KBUILD_CFLAGS += -Wno-sign-compare
>
> ---
> base-commit: 52a93d39b17dc7eb98b6aa3edb93943248e03b2f
> change-id: 20230807-missing_proto-0cb90ec6454c
>
> Best regards,
> --
> Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
>
