Messages in this thread | | | Date | Fri, 22 Dec 2017 13:58:50 -0800 | From | Guenter Roeck <> | Subject | Re: [PATCH 1/2] kbuild: Require a 'make clean' if we detect gcc changed underneath us |
| |
On Thu, Dec 21, 2017 at 05:53:02PM -0800, Douglas Anderson wrote: > Several people reported that the commit 3298b690b21c ("kbuild: Add a > cache for generated variables") caused them problems when they updated > gcc versions. Specifically the reports all looked something similar > to this: > > > In file included from ./include/uapi/linux/uuid.h:21:0, > > from ./include/linux/uuid.h:19, > > from ./include/linux/mod_devicetable.h:12, > > from scripts/mod/devicetable-offsets.c:2: > > ./include/linux/string.h:8:20: fatal error: stdarg.h: No such file or > > directory > > #include <stdarg.h> > > Masahiro Yamada determined that the problem was with: > > NOSTDINC_FLAGS += -nostdinc -isystem $(call shell-cached,$(CC) > -print-file-name=include) > > Specifically that the stale result of -print-file-name is stored in > the cache file. It was determined that a "make clean" fixed the > problems in all cases. > > In this particular case we could certainly try to clean just the cache > when we detect a gcc update, but it seems like overall it's a bad idea > to do an incremental build when gcc changes. We should warn the user > and tell them that they need a 'make clean'. > > Fixes: 3298b690b21c ("kbuild: Add a cache for generated variables") > Reported-by: Yang Shi <yang.s@alibaba-inc.com> > Reported-by: Dave Hansen <dave.hansen@intel.com> > Reported-by: Mathieu Malaterre <malat@debian.org> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
Unfortunately, it doesn't work as-is. Trying to build for mips with two different compilers, and trying to run "make clean" with the 2nd compiler version, results in:
scripts/Kbuild.include:490: *** Detected new CC version (050400 vs 040803). Please 'make clean'. Stop. Makefile:1297: recipe for target '_clean_.' failed make: *** [_clean_.] Error 2 make: *** Waiting for unfinished jobs.... scripts/Kbuild.include:490: *** Detected new CC version (050400 vs 040803). Please 'make clean'. Stop. Makefile:1297: recipe for target '_clean_arch/mips' failed make: *** [_clean_arch/mips] Error 2 scripts/Kbuild.include:490: *** Detected new CC version (050400 vs 040803). Please 'make clean'. Stop. Makefile:1297: recipe for target '_clean_arch/mips/boot/dts' failed make: *** [_clean_arch/mips/boot/dts] Error 2 make: *** wait: No child processes. Stop.
Guenter
| |