From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35725) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b2dGY-0006Ap-RS for qemu-devel@nongnu.org; Tue, 17 May 2016 07:34:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b2dGU-0000GA-Ia for qemu-devel@nongnu.org; Tue, 17 May 2016 07:34:21 -0400 References: <1463484451-22979-1-git-send-email-peter.maydell@linaro.org> From: Paolo Bonzini Message-ID: <573B01B1.5050008@redhat.com> Date: Tue, 17 May 2016 13:34:09 +0200 MIME-Version: 1.0 In-Reply-To: <1463484451-22979-1-git-send-email-peter.maydell@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] Remove config-devices.mak on 'make clean' List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org On 17/05/2016 13:27, Peter Maydell wrote: > Our dependency mechanism works like this: > * on first build there is neither a .o nor a .d > * we create the .d as a side effect of creating the .o > * for rebuilds we know when we need to update the .o, > which also updates the .d > > This system requires that you're never in a situation where there is > a .o file but no .d (because then we will never realise we need to > build the .d, and we will not have the dependency information about > when to rebuild the .o). > > This is working fine for our object files, but we also try to use it > for $TARGET/config-devices.mak (where the dependency file is > in $TARGET-config-devices.mak.d). Unfortunately "make clean" doesn't > remove config-devices.mak, which means that it puts us in the > forbidden situation of "object file exists but not its .d file". > This in turn means that we will fail to notice when we need to rebuild: > mkdir build/depbug > (cd build/depbug && '../../configure') > make -C build/depbug -j8 > make -C build/depbug clean > echo "CONFIG_CANARY = y" >> default-configs/arm-softmmu.mak > make -C build/depbug > grep CANARY build/depbug/aarch64-softmmu/config-devices.mak > > The CANARY token should show up in config-devices.mak but does not. > > Fix this bug by making "make clean" delete the config-devices.mak files. > config-all-devices.mak doesn't have the same problem since it has > no .d file, but delete it too, since it is created by "make" and > logically should be removed by "make clean". > > (Note that it is important not to remove config-devices.mak until > after we have recursively run 'make clean' in the subdirectories.) > > Signed-off-by: Peter Maydell > --- > Makefile | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/Makefile b/Makefile > index 1d076a9..a5d7e62 100644 > --- a/Makefile > +++ b/Makefile > @@ -356,6 +356,7 @@ clean: > if test -d $$d; then $(MAKE) -C $$d $@ || exit 1; fi; \ > rm -f $$d/qemu-options.def; \ > done > + rm -f $(SUBDIR_DEVICES_MAK) config-all-devices.mak > > VERSION ?= $(shell cat VERSION) > > Queued, thanks (and nice writeup too!) Paolo