Re: [patch] compiler, clang: suppress warning for unused static inline functions

[Ingo Molnar <mingo@kernel.org>]

* Matthias Kaehlcke <mka@chromium.org> wrote:

> El Wed, May 24, 2017 at 02:01:15PM -0700 David Rientjes ha dit:
> 
> > GCC explicitly does not warn for unused static inline functions for
> > -Wunused-function.  The manual states:
> > 
> > 	Warn whenever a static function is declared but not defined or
> > 	a non-inline static function is unused.
> > 
> > Clang does warn for static inline functions that are unused.
> > 
> > It turns out that suppressing the warnings avoids potentially complex
> > #ifdef directives, which also reduces LOC.
> > 
> > Supress the warning for clang.
> > 
> > Signed-off-by: David Rientjes <rientjes@google.com>
> > ---
> 
> As expressed earlier in other threads, I don't think gcc's behavior is
> preferable in this case. The warning on static inline functions (only
> in .c files) allows to detect truly unused code. About 50% of the
> warnings I have looked into so far fall into this category.
> 
> In my opinion it is more valuable to detect dead code than not having
> a few more __maybe_unused attributes (there aren't really that many
> instances, at least with x86 and arm64 defconfig). In most cases it is
> not necessary to use #ifdef, it is an option which is preferred by
> some maintainers. The reduced LOC is arguable, since dectecting dead
> code allows to remove it.

Static inline functions in headers are often not dead code.

Thanks,

	Ingo

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