Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755467Ab1DUWGu (ORCPT ); Thu, 21 Apr 2011 18:06:50 -0400 Received: from diomedes.noc.ntua.gr ([147.102.222.220]:54281 "EHLO diomedes.noc.ntua.gr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752428Ab1DUWGt (ORCPT ); Thu, 21 Apr 2011 18:06:49 -0400 Message-ID: <4DB0AA67.6030101@ece.ntua.gr> Date: Fri, 22 Apr 2011 01:06:31 +0300 From: Stratos Psomadakis User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.15) Gecko/20110402 Icedove/3.1.9 MIME-Version: 1.0 To: Sam Ravnborg CC: Michal Marek , linux-kbuild , lkml , Borislav Petkov Subject: Re: [RFC PATCH] kbuild: implement several W= levels References: <20110421213903.GB9660@merkur.ravnborg.org> In-Reply-To: <20110421213903.GB9660@merkur.ravnborg.org> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (diomedes.noc.ntua.gr [147.102.222.220]); Fri, 22 Apr 2011 01:06:35 +0300 (EEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5851 Lines: 143 On 22/04/2011 12:39 πμ, Sam Ravnborg wrote: > Building a kernel with "make W=1" produce far too much noise > to be usefull. > > Divide the warning options in three groups: > > W=1 - usefull warning options > W=2 - noisy but semi usefull warnign options > W=3 - almost pure noise options > > I do not feel strongly about the distinction between > group 2 and 3. But we should consider what we add in group 1. > > > Sample run on my box (x86, 32bit allyesconfig build) > CC kernel/bounds.s > kernel/bounds.c:14: warning: no previous prototype for ‘foo’ > GEN include/generated/bounds.h > CC arch/x86/kernel/asm-offsets.s > In file included from include/linux/sched.h:73, > from arch/x86/kernel/asm-offsets.c:9: > include/linux/signal.h: In function ‘sigorsets’: > include/linux/signal.h:121: warning: nested extern declaration of ‘_NSIG_WORDS_is_unsupported_size’ > include/linux/signal.h: In function ‘sigandsets’: > include/linux/signal.h:124: warning: nested extern declaration of ‘_NSIG_WORDS_is_unsupported_size’ > include/linux/signal.h: In function ‘signandsets’: > include/linux/signal.h:127: warning: nested extern declaration of ‘_NSIG_WORDS_is_unsupported_size’ > include/linux/signal.h: In function ‘signotset’: > include/linux/signal.h:151: warning: nested extern declaration of ‘_NSIG_WORDS_is_unsupported_size’ > arch/x86/kernel/asm-offsets.c: At top level: > arch/x86/kernel/asm-offsets.c:30: warning: no previous prototype for ‘common’ > > the patch is only an RFC - and is not made on top > of an upstream kernel with no additiona stuff applied. > > Sam > > diff --git a/Makefile b/Makefile > index b967b96..f0e138b 100644 > --- a/Makefile > +++ b/Makefile > @@ -103,7 +103,7 @@ ifeq ("$(origin O)", "command line") > endif > > ifeq ("$(origin W)", "command line") > - export KBUILD_ENABLE_EXTRA_GCC_CHECKS := 1 > + export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W) > endif > > # That's our default target when none is given on the command line > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index d5f925a..b65f820 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -56,31 +56,43 @@ endif > # $(call cc-option... ) handles gcc -W.. options which > # are not supported by all versions of the compiler > ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS > -KBUILD_EXTRA_WARNINGS := -Wextra > -KBUILD_EXTRA_WARNINGS += -Wunused -Wno-unused-parameter > -KBUILD_EXTRA_WARNINGS += -Waggregate-return > -KBUILD_EXTRA_WARNINGS += -Wbad-function-cast > -KBUILD_EXTRA_WARNINGS += -Wcast-qual > -KBUILD_EXTRA_WARNINGS += -Wcast-align > -KBUILD_EXTRA_WARNINGS += -Wconversion > -KBUILD_EXTRA_WARNINGS += -Wdisabled-optimization > -KBUILD_EXTRA_WARNINGS += -Wlogical-op > -KBUILD_EXTRA_WARNINGS += -Wmissing-declarations > -KBUILD_EXTRA_WARNINGS += -Wmissing-format-attribute > -KBUILD_EXTRA_WARNINGS += $(call cc-option, -Wmissing-include-dirs,) > -KBUILD_EXTRA_WARNINGS += -Wmissing-prototypes > -KBUILD_EXTRA_WARNINGS += -Wnested-externs > -KBUILD_EXTRA_WARNINGS += -Wold-style-definition > -KBUILD_EXTRA_WARNINGS += $(call cc-option, -Woverlength-strings,) > -KBUILD_EXTRA_WARNINGS += -Wpacked > -KBUILD_EXTRA_WARNINGS += -Wpacked-bitfield-compat > -KBUILD_EXTRA_WARNINGS += -Wpadded > -KBUILD_EXTRA_WARNINGS += -Wpointer-arith > -KBUILD_EXTRA_WARNINGS += -Wredundant-decls > -KBUILD_EXTRA_WARNINGS += -Wshadow > -KBUILD_EXTRA_WARNINGS += -Wswitch-default > -KBUILD_EXTRA_WARNINGS += $(call cc-option, -Wvla,) > -KBUILD_CFLAGS += $(KBUILD_EXTRA_WARNINGS) > +warning-1 := -Wextra > +warning-1 += -Wunused -Wno-unused-parameter > +warning-2 += -Waggregate-return > +warning-2 += -Wbad-function-cast > +warning-2 += -Wcast-qual > +warning-2 += -Wcast-align > +warning-3 += -Wconversion > +warning-2 += -Wdisabled-optimization > +warning-2 += -Wlogical-op > +warning-1 += -Wmissing-declarations > +warning-1 += -Wmissing-format-attribute > +warning-1 += $(call cc-option, -Wmissing-include-dirs,) > +warning-1 += -Wmissing-prototypes > +warning-1 += -Wnested-externs > +warning-2 += -Wold-style-definition > +warning-2 += $(call cc-option, -Woverlength-strings,) > +warning-3 += -Wpacked > +warning-3 += -Wpacked-bitfield-compat > +warning-3 += -Wpadded > +warning-3 += -Wpointer-arith > +warning-2 += -Wredundant-decls > +warning-2 += -Wshadow > +warning-3 += -Wswitch-default > +warning-3 += $(call cc-option, -Wvla,) > +ifeq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),1) > + KBUILD_CFLAGS += $(warning-1) > +else > + ifeq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),2) > + KBUILD_CFLAGS += $(warning-1) $(warning-2) > + else > + ifeq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),3) > + KBUILD_CFLAGS += $(warning-1) $(warning-2) $(warning-3) > + else > + $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown) > + endif > + endif > +endif > endif > > include scripts/Makefile.lib > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ Just started looking at the patch. I tested it and -Wnested-externs is causing a *lot* of noise, because of the nested extern ‘_NSIG_WORDS_is_unsupported_size’ in include/linux/signal.h, which gets included a lot. So, unless that changes, I think that it shouldn't be enabled for W=1. -- Stratos Psomadakis -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/