From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36522) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eyG8K-00005T-TI for qemu-devel@nongnu.org; Tue, 20 Mar 2018 08:12:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eyG8G-0008SQ-US for qemu-devel@nongnu.org; Tue, 20 Mar 2018 08:12:52 -0400 Date: Tue, 20 Mar 2018 14:12:24 +0200 From: "Michael S. Tsirkin" Message-ID: <20180320141107-mutt-send-email-mst@kernel.org> References: <1521510562-529051-1-git-send-email-mst@redhat.com> <8f06e1e3-4823-d8e8-43bd-c092c523849e@vivier.eu> <20180320094406.GD4530@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20180320094406.GD4530@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] qemu: include generated files with <> and not "" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Cc: Laurent Vivier , qemu-devel@nongnu.org, Paolo Bonzini , Peter Crosthwaite , Richard Henderson , Gerd Hoffmann , Eduardo Habkost , Igor Mammedov , Kevin Wolf , Max Reitz , Jeff Cody , Fam Zheng , John Snow , Stefan Weil , Stefan Hajnoczi , Ronnie Sahlberg , Peter Lieven , Eric Blake , Markus Armbruster , Alberto Garcia , Josh Durgin , Hitoshi Mitake , Liu Yuan , "Richard W.M. Jones" , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , "Dr. David Alan Gilbert" , Greg Kurz , Ben Warren , Peter Maydell , Shannon Zhao , Michael Walle , Keith Busch , Stefano Stabellini , Anthony Perard , Fabien Chouteau , Amit Shah , Marcel Apfelbaum , Mark Cave-Ayland , BALATON Zoltan , Alexander Graf , Cornelia Huck , Christian Borntraeger , David Gibson , Corey Minyard , =?iso-8859-1?Q?Herv=E9?= Poussineau , Peter Chubb , Subbaraya Sundeep , Dmitry Fleytman , Jason Wang , Yongbok Kim , Max Filippov , Jiri Pirko , Yuval Shaia , David Hildenbrand , Hannes Reinecke , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Andrzej Zaborowski , Artyom Tarasenko , Alistair Francis , "Edgar E. Iglesias" , Stefan Berger , Alex Williamson , zhanghailiang , Juan Quintela , Michael Roth , Andreas =?iso-8859-1?Q?F=E4rber?= , Pavel Dovgalyuk , Riku Voipio , Zhang Chen , Li Zhijian , Wen Congyang , Xie Changlong , Marcelo Tosatti , Aurelien Jarno , kvm@vger.kernel.org, qemu-block@nongnu.org, sheepdog@lists.wpkg.org, qemu-arm@nongnu.org, xen-devel@lists.xenproject.org, qemu-ppc@nongnu.org, qemu-s390x@nongnu.org, Thomas Huth On Tue, Mar 20, 2018 at 09:44:06AM +0000, Daniel P. Berrang=E9 wrote: > On Tue, Mar 20, 2018 at 09:58:23AM +0100, Laurent Vivier wrote: > > Le 20/03/2018 =E0 02:54, Michael S. Tsirkin a =E9crit=A0: > > > QEMU coding style at the moment asks for all non-system > > > include files to be used with #include "foo.h". > > > However this rule actually does not make sense and > > > creates issues for when the included file is generated. > >=20 > > If you change that, we can have issue when a system include has the s= ame > > name as our local include. With "", system header are taken fir= st. >=20 > > > In C, include "file" means look in current directory, > > > then on include search path. Current directory here > > > means the source file directory. > > > By comparison include means look on include search path. > >=20 > > Not exactly, there is the notion of "system header" too. > >=20 > > https://gcc.gnu.org/onlinedocs/cpp/Include-Syntax.html > >=20 > > #include > > This variant is used for system header files. It searches for a file > > named file in a standard list of system directories. You can prepend > > directories to this list with the -I option (see Invocation). > >=20 > > #include "file" > > This variant is used for header files of your own program. It searche= s > > for a file named file first in the directory containing the current > > file, then in the quote directories and then the same directories use= d > > for . You can prepend directories to the list of quote director= ies > > with the -iquote option. > >=20 > > > As generated files are not in the search directory (unless the buil= d > > > directory happens to match the source directory), it does not make = sense > > > to include them with "" - doing so is merely more work for preproce= ssor > > > and a source or errors if a stale file happens to exist in the sour= ce > > > directory. > >=20 > > I agree there is a problem with stale files. But linux, for instance, > > asks for a "make mrproper" to avoid this. >=20 > We can follow what autoconf does, and add a check to configure to see i= f > there are generated files left in the source dir, when configuring with > builddir !=3D srcdir, and exit with error, telling user to clean their > src dir first. >=20 > > > This changes include directives for all generated files, across the > > > tree. The idea is to avoid sending a huge amount of email. But whe= n > > > merging, the changes will be split with one commit per file, e.g. f= or > > > ease of bisect in case of build failures, and to ease merging. > > >=20 > > > Note that should some generated files be missed by this tree-wide > > > refactoring, it isn't a big deal - this merely maintains the status= quo, > > > and this can be addressed by a separate patch on top. > > >=20 > > > Signed-off-by: Michael S. Tsirkin > >=20 > > I think your idea conflicts with what Markus has started to do: >=20 > Yes, I don't think we should revert what Markus started. Both ways of > referencing QEMU headers have downsides, but I think "..." has fewer > downsides that "<....">. Could you please explain what the advantage of "" is? It seems to be gone since we moved headers away from source. > The problem Michael is tackling should be pretty rare, because moist > developers aren't frequently switching between srcdir=3D=3Dbuilddir and > srcdir!=3Dbiulddir setups - they have their preference for which to use > and stick with it. As long as we get ./configure to warn about the > dirty srcdir it should be good enough >=20 > Regards, > Daniel > --=20 > |: https://berrange.com -o- https://www.flickr.com/photos/dberr= ange :| > |: https://libvirt.org -o- https://fstop138.berrange= .com :| > |: https://entangle-photo.org -o- https://www.instagram.com/dberr= ange :|