MIPS parallel build breakage

[Sascha Hauer]

On Thu, Mar 01, 2018 at 12:07:29PM +0100, Sascha Hauer wrote:
> Hi Sam and Antony,
> 
> (Antony because you introduced this and Sam because you have intimate
> knowledge with our build system ;)
> 
> I am trying to solve a problem that annoys me for some years now. The
> problem is that the MIPS defconfigs regularly fail in my autobuilder.
> I usually help myself with trying it again and most of the time it
> then works, but doing this for years increases the pressure to do
> something.
> 
> What happens is that the MIPS builds use include/generated/compile.h:
> 
> > arch/mips/include/asm/pbl_macros.h:28:#include <generated/compile.h>
> 
> This often ends in:
> 
> > In file included from arch/mips/boot/start.S:20:0: arch/mips/include/asm/pbl_macros.h:28:31:
> > fatal error: generated/compile.h: No such file or directory
> > compilation terminated.
> 
> include/generated/compile.h is generated in common/Makefile:
> 
> > include/generated/compile.h: FORCE
> > 	@$($(quiet)chk_compile.h)
> > 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
> > 	"$(UTS_MACHINE)" "$(CC) $(KBUILD_CFLAGS)"
> 
> Other users of this file add an explicit dependency on it:
> 
> > # dependencies on generated files need to be listed explicitly
> > $(obj)/version.o: include/generated/compile.h
> 
> This only seems to work though when the dependent file is in the same
> directory, but not when the file is in arch/mips/boot/.
> 
> I tried doing the include/generated/compile.h in Makefile instead of
> common/Makefile, but then the version counting gets confused and causes
> unnecessary rebuilds.
> 
> Any ideas how to solve this?

We still have no solution for this. I dropped MIPS from my autobuilder,
so we won't catch any build errors on MIPS anymore :(

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |