[U-Boot] [PATCH] tools/Makefile: fix HOSTCFLAGS with CROSS_BUILD_TOOLS

Thu Nov 14 16:41:42 UTC 2019

On Thu, Nov 14, 2019 at 05:28:06PM +0100, Jan Kiszka wrote:
> On 26.08.19 08:43, Fabrice Fontaine wrote:
> > Le lun. 26 août 2019 à 07:57, Jan Kiszka <jan.kiszka at web.de> a écrit :
> > > 
> > > On 25.08.19 21:11, Fabrice Fontaine wrote:
> > > > Le dim. 25 août 2019 à 17:49, Jan Kiszka <jan.kiszka at web.de> a écrit :
> > > > > 
> > > > > On 25.08.19 17:13, Fabrice Fontaine wrote:
> > > > > > Le dim. 25 août 2019 à 16:11, Jan Kiszka <jan.kiszka at web.de> a écrit :
> > > > > > > 
> > > > > > > On 25.08.19 15:43, Fabrice Fontaine wrote:
> > > > > > > > Hello,
> > > > > > > > Le dim. 25 août 2019 à 13:44, Jan Kiszka <jan.kiszka at web.de> a écrit :
> > > > > > > > > 
> > > > > > > > > On 01.05.19 15:08, Fabrice Fontaine wrote:
> > > > > > > > > > When CROSS_BUILD_TOOLS is set, set HOSTCFLAGS to CFLAGS otherwise CC
> > > > > > > > > > will be used with HOSTCFLAGS which seems wrong
> > > > > > > > > > 
> > > > > > > > > > Signed-off-by: Fabrice Fontaine <fontaine.fabrice at gmail.com>
> > > > > > > > > > ---
> > > > > > > > > >       tools/Makefile | 1 +
> > > > > > > > > >       1 file changed, 1 insertion(+)
> > > > > > > > > > 
> > > > > > > > > > diff --git a/tools/Makefile b/tools/Makefile
> > > > > > > > > > index 12a3027e23..eadeba417d 100644
> > > > > > > > > > --- a/tools/Makefile
> > > > > > > > > > +++ b/tools/Makefile
> > > > > > > > > > @@ -272,6 +272,7 @@ subdir- += env
> > > > > > > > > > 
> > > > > > > > > >       ifneq ($(CROSS_BUILD_TOOLS),)
> > > > > > > > > >       override HOSTCC = $(CC)
> > > > > > > > > > +override HOSTCFLAGS = $(CFLAGS)
> > > > > > > > > > 
> > > > > > > > > >       quiet_cmd_crosstools_strip = STRIP   $^
> > > > > > > > > >             cmd_crosstools_strip = $(STRIP) $^; touch $@
> > > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > This eats - among other things - -O2, normally set in /Makefile. And that breaks
> > > > > > > > > CROSS_BUILD_TOOLS=y with CONFIG_FIT but without CONFIG_FIT_SIGNATURE because "if
> > > > > > > > > (!IMAGE_ENABLE_SIGN)" is no longer optimized. I tend to believe this should
> > > > > > > > > simply be reverted (which is what I'm doing locally in order to fix my builds).
> > > > > > > > I don't think this patch should be reverted, I sent it to fix a
> > > > > > > > cross-compilation build issue with host-openssl.
> > > > > > > > 
> > > > > > > > Indeed, without this patch, with CROSS_BUILD_TOOLS=y, tools/Makefile
> > > > > > > > sets HOSTCC=$(CC) but it forgets
> > > > > > > > to override HOSTCFLAGS, though, so the tools are built with target
> > > > > > > > compiler but host CFLAGS.
> > > > > > > > 
> > > > > > > > This raises a build failure if host-openssl is built before uboot-tools because
> > > > > > > > uboot-tools links with openssl headers from host which depends on pthread.h
> > > > > > > > 
> > > > > > > > More information can be found on buildroot's patchwork here:
> > > > > > > > - https://patchwork.ozlabs.org/patch/1092227
> > > > > > > > - https://patchwork.ozlabs.org/patch/1093385
> > > > > > > > > 
> > > > > > > > > Jan
> > > > > > > > 
> > > > > > > > Best Regards,
> > > > > > > > 
> > > > > > > > Fabrice
> > > > > > > > 
> > > > > > > 
> > > > > > > So what is your suggestion to fix the O2-regression best?
> > > > > > I'm far from being an expert in uboot so please excuse me if my answer
> > > > > > contains some mistakes.
> > > > > > However, IMHO, we should not pass -O2 or any other optimization flags.
> > > > > >    From my understanding, CFLAGS (and so HOSTCFLAGS when building tools
> > > > > > for the target through cross-tools) will (or should?) contain -O2 or
> > > > > > -Os depending on CONFIG_CC_OPTIMIZE_FOR_SIZE value.
> > > > > > However, I do understand that this is a change in the former behavior
> > > > > > that was always passing -O2 in HOSTCFLAGS.
> > > > > > So, if you really want to pass -O2, I would add it to HOSTCFLAGS in
> > > > > > tools/Makefile (after the override).
> > > > > 
> > > > > This is a hack. U-boot relies on >= -O2 for proper build, so it must inject this
> > > > > setting on its own - which it did prior to your change. I think top-level
> > > > > HOSTCFLAGS belongs to the build, irrespective of native vs. cross. You may allow
> > > > > appending (and, thus, overwriting) settings but you cannot remove mandatory ones.
> > > > > 
> > > > > > However, I have to confess that I don't understand why the build
> > > > > > breaks "if (!IMAGE_ENABLE_SIGN)" is no longer optimized."
> > > > > 
> > > > > IMAGE_ENABLE_SIGN is 0 when CONFIG_FIT_SIGNATURE is not set. That will remove
> > > > > all code from tools/image-host.c which is not reachable then. When it's not
> > > > > removed because of default optimization settings, we get linker errors because
> > > > > common/image.sig.c is not built without CONFIG_FIT_SIGNATURE. I assume this way
> > > > > was preferred over #ifdef'ery, but it's broken now.
> > > > Thanks a lot for your explanation.
> > > > I was able to reproduce the issue and I think that
> > > > https://github.com/ffontaine/u-boot/commit/61a162e5c0343fc55304902042f8c9adfe531f51
> > > > should fixed it.
> > > > Can you review it? I can also directly send a PR.
> > > 
> > > I still think that dropping the content of HOSTCFLAGS is the actual bug. There
> > > is more than -O2 that you lose. If you want your CFLAGS to be respected, append
> > > them.
> > I add Arnout to the list to get his feedback as he is the one that
> > suggested this solution during review of
> > https://patchwork.ozlabs.org/patch/1092227.
> 
> Nothing happened, bug is still present in master. Any suggestions how to
> resolve it?

OK, I've looked over the thread again.  Where and how are you hitting a
problem here again?  This area is indeed a bit funky and I see
OpenEmbedded has long been doing "shove everything we need in via CC, do
not use CFLAGS/etc".  Thanks!

-- 
Tom
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