From patchwork Fri Oct 19 13:54:23 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Makefile: Forbid out-of-tree build from a source tree that has been built in Date: Fri, 19 Oct 2012 03:54:23 -0000 From: Peter Maydell X-Patchwork-Id: 192706 Message-Id: <1350654863-26048-1-git-send-email-peter.maydell@linaro.org> To: qemu-devel@nongnu.org Cc: patches@linaro.org If we try to do an out-of-tree build but the source tree we're building from has been used in the past for an in-tree build then things will go confusingly wrong. Specifically, some parts of the build process will pull in generated files from the old in-tree build (because SRC_PATH is on the vpath). Diagnose this situation so we can produce a useful error message and tell the user how to fix it (run distclean in the source tree). Signed-off-by: Peter Maydell --- I got bitten by this again the other day so I figured it was worth adding a molly-guard. The check is not perfect (it won't notice if you did a distclean but didn't delete the *-softmmu &c directories, for instance) but it should catch most cases of this user error. Makefile | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Makefile b/Makefile index a9c22bf..5094a08 100644 --- a/Makefile +++ b/Makefile @@ -8,6 +8,17 @@ ifneq ($(wildcard config-host.mak),) # Put the all: rule here so that config-host.mak can contain dependencies. all: include config-host.mak + +# Check that we're not trying to do an out-of-tree build from +# a tree that's been used for an in-tree build. +ifneq ($(realpath $(SRC_PATH)),$(realpath .)) +ifneq ($(wildcard $(SRC_PATH)/config-host.mak),) +$(error This is an out of tree build but your source tree ($(SRC_PATH)) \ +seems to have been used for an in-tree build. You can fix this by running \ +"make distclean && rm -rf *-linux-user *-softmmu" in your source tree) +endif +endif + include $(SRC_PATH)/rules.mak config-host.mak: $(SRC_PATH)/configure @echo $@ is out-of-date, running configure