Re: [PATCH 2/2] kbuild: clang: Disable the 'duplicate-decl-specifier' warning

Doug Anderson
2017-05-16T21:41:20Z

Hi

On Fri, Apr 21, 2017 at 2:39 PM, Matthias Kaehlcke <mka@chromium.org> wrote:
> clang generates plenty of these warnings in different parts of the code.
> They are mostly caused by container_of() and other macros which declare
> a "const <type> *" variable for their internal use which triggers a
> "duplicate 'const' specifier" warning if the <type> is already const
> qualified.
>
> Wording-mostly-from: Michael Davidson <md@google.com>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
> Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/Makefile b/Makefile
> index df5abf346354..6cd6d428db43 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -704,6 +704,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)
> KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
> KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
> KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
> +KBUILD_CFLAGS += $(call cc-disable-warning, duplicate-decl-specifier)
> # Quiet clang warning: comparison of unsigned expression < 0 is always false
> KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
> # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the

It seems like gcc 7 may have the same warning. Specifically I saw a
patch fly by from Arnd, which you can find in Mark Brown's tree now:

https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/commit/?h=topic/rt5614&id=03ba791df98d15d07ea74075122af71e35c7611c

+Arnd since he may be trying to solve the same issues?

-Doug