Re: [PATCH] Makerules: pass CFLAGS when building .S files, BZ #23273

[Florian Weimer <fweimer@redhat.com>]

On 06/11/2018 03:18 PM, Sergei Trofimovich wrote:
> On Mon, 11 Jun 2018 14:50:24 +0200
> Florian Weimer <fweimer@redhat.com> wrote:
> 
>> On 06/11/2018 02:35 PM, Sergei Trofimovich wrote:
>>> On Mon, 11 Jun 2018 08:17:37 -0300
>>> Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
>>>    
>>>> On 11/06/2018 07:46, Florian Weimer wrote:
>>>>> On 06/11/2018 12:28 PM, Sergei Trofimovich wrote:
>>>>>> When glibc is built on armv7 with CFLAGS="-pipe -march=armv7-a -O2 -mfpu=neon"
>>>>>> rtld fails to link due to missing memcpy symbol.
>>>>>>
>>>>>> This happens because .c files are built with -mfpu=neon flag but .S/.s files
>>>>>> are built without it. Among other things -mfpu=neon defines __ARM_NEON__.
>>>>>>
>>>>>> To fix this mismatch CFLAGS should be passed consistently to .c and .S files.
>>>>>
>>>>> Please check if you can fix this by putting the architecture selection flags into the CC and CXX variables when invoking configure.
>>>
>>> I'm not sure just adding an arch flag is enough:
>>>       https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/arm/armv7/multiarch/memcpy_neon.S;h=1a8d8bbe9e128618105be0652de42a34fbc52d73;hb=HEAD
>>>      ...
>>>      2 #ifndef __ARM_NEON__
>>>      3 # define memcpy __memcpy_neon
>>> Here memcpy_neon.S explicitly supports both neon-enabled and disabled flags.
>>
>> Does this mean your proposed patch fails to address the issue, too?
> 
> My proposed patch fixes ld.so linkage (and ld.so seems to work).

Yes, but what about using CC/CXX setting at configure time to achieve 
the same effect?

Thanks,
Florian