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

[Jan Kiszka]

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?

Jan