[Mesa-dev] [PATCH] docs/autoconf: mention CC/CXX when doing multilib builds

[Ilia Mirkin]

On Wed, Aug 13, 2014 at 5:56 PM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> On 13/08/14 22:22, Ilia Mirkin wrote:
>> On Wed, Aug 13, 2014 at 5:16 PM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
>>> Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
>>> ---
>>>
>>> Unless someone object I would like to squash this patch with the
>>> previous one.
>>>
>>> -Emil
>>>
>>>  docs/autoconf.html | 16 ++++++++++++++--
>>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/docs/autoconf.html b/docs/autoconf.html
>>> index f27838f..c225659 100644
>>> --- a/docs/autoconf.html
>>> +++ b/docs/autoconf.html
>>> @@ -141,14 +141,26 @@ assembly will not be used.</p>
>>>  <dt><code>--host=</code></dt>
>>>  <dd><p>By default, the build will compile code for the architecture that
>>>  it's running on. In order to build Mesa on a x64-86 machine that is to run
>>
>> While you're fixing stuff, x86-64
>>
> Ack, will do.
>
>>> -on a i686, one would need to set the options to:
>>> +on a i686, one would need to set the options to:</p>
>>>
>>>  <p><code>--build=i686-pc-linux-gnu --host=i686-pc-linux-gnu</code></p>
>>>
>>>  Note that these can vary from distribution to distribution. For more
>>>  information check with the
>>>  <a href="https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Specifying-Target-Triplets.html">
>>> -autoconf manual</a>.</p>
>>> +autoconf manual</a>.
>>> +
>>> +
>>> +<p>In some cases a single compiler is capable of handling both architectures
>>> +in that case one would need to set the <code>CC,CXX</code> variables
>>> +appending the correct machine options. Seek your compiler documentation for
>>> +further information -
>>> +<a href="https://gcc.gnu.org/onlinedocs/gcc/Submodel-Options.html"> gcc
>>> +machine dependent options</a></p>
>>> +
>>> +<p>The following is the complete setup needed to compile on my Archlinux setup</p>
>>
>> There's nothing about the below that's specific to Arch, or any
>> distro, really -- I'd avoid the explicit distro reference.
> Haven't touched any other distro but Arch in years. Yet it makes sense to drop
> the distro reference but keep the example.

Right, I was suggesting s/Archlinux// :)

>
>> Do you
>> actually need the --build and --host things? I thought that was if you
>> were going to use a cross-compiler. I only have
>> x86_64-pc-linux-gnu-gcc, no i686-...-gnu-gcc.
>>
> --build/host (at lest) used to be required by mesa, as some bits were built
> differently when doing cross-compilation. Not sure what the case is now - I
> care not look in src/{glsl,mesa} which is where all of that chaos was.

But that's my point -- it's not a cross-compilation. It's using the
same system compiler. The way cross-compilation works (afaik) is that
you just look for $host-gcc, $host-ld, $host-as etc (and use
$build-gcc, etc for the binaries that need to be run as part of the
build). But i686-...-gcc is not a binary available on my system. So
the cross-compilation will fail...

Perhaps I'm just misunderstanding how things work though.

>
>
>> In the past I've just done CFLAGS=-m32 CXXFLAGS=-m32 and it has worked
>> like a charm. But perhaps there's a downside to doing that...
>>
> I cannot think of any side effects to be honest (barring any bugs in mesa).
> Yet I would love if people avoid touching any *FLAGS :)
>
> Thanks
> -Emil
>
>>> +
>>> +<code>./configure CC="gcc -m32" CXX="g++ -m32" --build=i686-unknown-linux-gnu --host=i686-unknown-linux-gnu ...</code>
>>>  </dd>
>>>  </dl>
>>>
>>> --
>>> 2.0.2
>>>
>>> _______________________________________________
>>> mesa-dev mailing list
>>> mesa-dev at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>