On Mon, Jul 25, 2011 at 2:57 PM, Michael Roth <mdr...@linux.vnet.ibm.com> wrote: > On 07/25/2011 07:43 AM, Stefan Hajnoczi wrote: >> >> On Mon, Jul 25, 2011 at 1:16 PM, Michael Roth<mdr...@linux.vnet.ibm.com> >> wrote: >>> >>> On 07/25/2011 05:15 AM, Stefan Hajnoczi wrote: >>>> >>>> On Thu, Jul 21, 2011 at 5:41 AM, Alexandre Raymond<cerb...@gmail.com> >>>> wrote: >>>>> >>>>> This patch fixes a minor bugs which prevented QEMU from being built >>>>> out of tree. >>>>> >>>>> Signed-off-by: Alexandre Raymond<cerb...@gmail.com> >>>>> --- >>>>> Makefile | 2 +- >>>>> 1 files changed, 1 insertions(+), 1 deletions(-) >>>> >>>> I don't normally use --source-path but it still seems broken to me >>>> after applying your patch? >>>> >>>> $ cd /tmp; mkdir out; cd out >>>> $ ~/qemu/configure --source-path=$HOME/qemu >>>> $ make >>>> GEN config-all-devices.mak >>>> cat: i386-softmmu/config-devices.mak: No such file or directory >>>> cat: x86_64-softmmu/config-devices.mak: No such file or directory >>>> cat: alpha-softmmu/config-devices.mak: No such file or directory >>>> >>>> Stefan >>>> >>> >>> Works okay for me with and without the patch if I do a `make distclean` >>> in >>> $HOME/qemu beforehand. >>> >>> Not sure what the trigger is for the breakage Alexandre is trying to >>> address. >> >> You are right that make distclean in the source directory solves the >> issue. >> >> Intuitively I expect ./configure to re-wire things, make distclean >> should not be necessary. >> >> Alexandre: Can you describe the case where you hit a build issue in more >> detail? >> >> Stefan > > The root problem seems to be that by including $(SRC_DIR) in VPATH (via > $(call set-vpath, $(SRC_PATH):$(SRC_PATH)/hw)), $(SRC_DIR) ends up being > searched for source files as well as target dependencies. So any crud left > in there can still satisfy dependencies when building outside $SRC_PATH. I'm > not sure there's a simple way around this except to prefix all source files > with $(SRC_PATH) and remove $(SRC_PATH) from VPATH...I'm not even sure that > would work though.. > > Perhaps just a friendly error message if we detect the $(SRC_PATH) directory > needs a distclean? Once you know that's the magic fix it's not terribly > inconvenient....alternatively we could automatically do the distclean in > $SRC_PATH but that might be considered overstepping our bounds.
Yes, ./configure could detect the case where --source-path= is used but the source tree has build outputs. > Consequently, it seems like this patch would be a noop...default-configs > should never exist in an external build directory, so > $(SRC_PATH)/default-configs and default-configs end up being equivalent when > make eventually find it in $(SRC_PATH). Thanks for finding out what is happening. My understanding is that $(SRC_PATH) must be used when invoking external commands during the build, since they don't perform vpath search. For make targets we don't need to use $(SRC_PATH) since the vpath is in effect. Stefan
