[Buildroot] [PATCH 4/5] package/mesa3d: explicitely disable asm

Romain Naour romain.naour at gmail.com
Wed Mar 29 21:55:12 UTC 2017


Hi Thomas, Bernd, All,

Le 29/03/2017 à 23:35, Thomas Petazzoni a écrit :
> Hello,
> 
> On Wed, 29 Mar 2017 23:28:56 +0200, Romain Naour wrote:
> 
>> Le 29/03/2017 à 06:41, Bernd Kuhls a écrit :
>>> Am Sun, 26 Mar 2017 18:28:52 +0200 schrieb Romain Naour:
>>>   
>>>> assembly are enabled by default on supported plaforms even while
>>>> crosscompiling if host == target:
>>>>
>>>> checking whether to enable assembly... yes, x86_64
>>>>
>>>> It was also disabled in the mesa package in Fedora since 7.6 [1].
>>>>
>>>> [1] http://pkgs.fedoraproject.org/cgit/rpms/mesa.git/commit/?id=629c8726  
>>>
>>> Hi,
>>>
>>> I am unsure about this patch, why shouldn't we use asm code when 
>>> crosscompiling for host == target CPU?  
>>
>> To be honest I don't really have an issue with assembly being enabled for my use
>> case. But there is an issue when you want a reproducible build with the same
>> defconfig build on a x86 and x86_64 host.
> 
> For which architectures is the assembly code available? We should
> forcefully enable it for those architectures.

Assembly code is available for x86, x86_64/amd64 and sparc (see configure.ac).

The issue while cross-compiling is when assembly are enabled, the build system
build and run a small tool called gen_matypes on the host.

"disable if cross compiling on x86/x86_64 since we must run gen_matypes"

So it allow to enable assembly code while cross-compiling only when the host =
target.

> 
> I agree with Romain that we shouldn't depend on something that looks at
> the architecture of the host machine to decide if a feature for the
> target should be enabled or not.

I believe we don't have the choice... we need to disable it.

Best regards,
Romain

> 
> Thomas
> 



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