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

[Fabrice Fontaine]

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.
>
> Jan
Fabrice