[FFmpeg-devel] Building for Mac x86 with GCC & NASM

[Martin Storsjö]

On Wed, 28 May 2025, softworkz . wrote:

>> -----Original Message-----
>> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
>> Christopher Snowhill
>> Sent: Mittwoch, 28. Mai 2025 09:40
>> To: FFmpeg development discussions and patches <ffmpeg-
>> devel at ffmpeg.org>
>> Subject: Re: [FFmpeg-devel] Building for Mac x86 with GCC & NASM
>>
>> On Tue May 27, 2025 at 10:54 PM PDT, Martin Storsjö wrote:
>>> On Tue, 27 May 2025, softworkz . wrote:
>>>
>>>> Hi,
>>>>
>>>> I have an issue with the CI builds for Mac in a way that it prints
>>>> tons of lines like this:
>>>>
>>>> ld: warning: no platform load command found in
>> 'libavcodec/libavcodec.a[1008](sao_10bit.o)', assuming: macOS
>>>> ld: warning: no platform load command found in
>> 'libavcodec/libavcodec.a[1009](hpeldsp.o)', assuming: macOS
>>>> ld: warning: no platform load command found in
>> 'libavcodec/libavcodec.a[1011](huffyuvdsp.o)', assuming: macOS
>>>> ld: warning: no platform load command found in
>> 'libavcodec/libavcodec.a[1013](huffyuvencdsp.o)', assuming: macOS
>>>>
>>>>
>>>> These are all about X86AM output. I've had those lines for all .o
>> files
>>>> before and was able to get rid of them by adding flags like below.
>>>>
>>>> Does anybody know how I can avoid those lines for the X86ASM output
>> as well?
>>>> (don't know much about building for Apple)
>>>
>>> These warnings appeared since the new linker in Xcode 15.0, 1.5
>> years ago.
>>> I'm not aware of a flag for silencing these warnings; the only way
>> I'm
>>> aware of is to force using the old linker by passing -Wl,-
>> ld_classic.
>>>
>>> These warnings would go away of nasm could produce the right
>> platform load
>>> commands; this is https://github.com/netwide-assembler/nasm/pull/13,
>> but
>>> there hasn't been much progress on it. (And since the macOS
>> ecossytem
>>> mostly is moving away from x86, I guess there's progressively less
>> effort
>>> on it as well.)
>>>
>>> // Martin
>>
>> I do wonder how this is going, since I have never noticed such
>> messages
>> while building for x86 from an ARM machine. I continue to support x86
>> machines all the way down to the minimum spec of current Xcode, which
>> is
>> 10.13.
>
> I don't think you can cross-compile x86 assembler on an arm machine.

Why wouldn't you be able to do that? The assembler is an executable like 
any other, taking in source code and outputting object files. You can run 
that on any machine.

// Martin