From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 9F8316B0279 for ; Thu, 25 May 2017 12:14:08 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id m5so234788093pfc.1 for ; Thu, 25 May 2017 09:14:08 -0700 (PDT) Received: from mail-pf0-x232.google.com (mail-pf0-x232.google.com. [2607:f8b0:400e:c00::232]) by mx.google.com with ESMTPS id a8si28278219plt.238.2017.05.25.09.14.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 May 2017 09:14:07 -0700 (PDT) Received: by mail-pf0-x232.google.com with SMTP id m17so171520784pfg.3 for ; Thu, 25 May 2017 09:14:07 -0700 (PDT) Date: Thu, 25 May 2017 09:14:06 -0700 From: Matthias Kaehlcke Subject: Re: [patch] compiler, clang: suppress warning for unused static inline functions Message-ID: <20170525161406.GT141096@google.com> References: <20170524212229.GR141096@google.com> <20170525055207.udcphnshuzl2gkps@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170525055207.udcphnshuzl2gkps@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar Cc: David Rientjes , Andrew Morton , Christoph Lameter , Pekka Enberg , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Douglas Anderson , Mark Brown , David Miller El Thu, May 25, 2017 at 07:52:07AM +0200 Ingo Molnar ha dit: > > * Matthias Kaehlcke 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 > > > --- > > > > 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. Sure, there is no intention to delete these and clang doesn't raise warnings about unused static inline functions in headers. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org