[FFmpeg-devel] [PATCH] set HAVE_MMX2 in config.h

[Gert Vervoort]

Diego Biurrun wrote:
> On Wed, Mar 19, 2008 at 01:34:23AM -0400, Alexander Strange wrote:
>   
>> On Wed, Mar 19, 2008 at 1:08 AM, Alexander Strange
>> <astrange at ithinksw.com> wrote:
>>     
>>> On Tue, Mar 18, 2008 at 11:03 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
>>>  >
>>>  > On Tue, Mar 18, 2008 at 10:37:34PM -0400, Alexander Strange wrote:
>>>  >  >
>>>  >  > On Mar 18, 2008, at 5:57 PM, Gert Vervoort wrote:
>>>  >  >>
>>>  >  >> Enabling HAVE_MMX2 for swscale gives an linker error on x86-64 when
>>>  >  >> compiling as a shared library:
>>>  >  >>
>>>  >  >> gcc -shared -Wl,-soname,libswscale.so.0 -L"/tmp/ffmpeg"/libavutil
>>>  >  >> -rdynamic -export-dynamic -Wl,--warn-common -Wl,--as-needed
>>>  >  >> -Wl,-rpath-link,"/tmp/ffmpeg"/libavcodec
>>>  >  >> -Wl,-rpath-link,"/tmp/ffmpeg"/libavformat
>>>  >  >> -Wl,-rpath-link,"/tmp/ffmpeg"/libavutil -Wl,-Bsymbolic -o
>>>  >  >> libswscale.so.0 rgb2rgb.o swscale.o yuv2rgb.o -lavutil -lz -pthread -lm
>>>  >  >> -lamrnb -lm -lamrwb -lm -lfaac -lfaad -lmp3lame -lm   -ldl -ldl -lX11
>>>  >  >> -lXext
>>>  >  >> /usr/bin/ld: swscale.o: relocation R_X86_64_32S against `a local symbol'
>>>  >  >> can not be used when making a shared object; recompile with -fPIC
>>>  >  >> swscale.o: could not read symbols: Bad value
>>>  >  >> collect2: ld returned 1 exit status
>>>  >  >> make[1]: *** [libswscale.so.0] Error 1
>>>  >  >> make[1]: Leaving directory `/tmp/ffmpeg/libswscale'
>>>  >  >> make: *** [lib] Error 2
>>>  >  >> [gert at apollo ffmpeg]$
>>>  >  >
>>>  >  > The attached patch fixes 64-bit but breaks any system with an
>>>  >  > EXTERN_PREFIX.
>>>  >  > Suggestions?
>>>  >
>>>  >  Well figure out the proper syntax for all the systems and do whatever
>>>  >  is needed so that it ends in there.
>>>  >
>>>  >  [...]
>>>
>>>  This patch generates the right asm by making a new LOCAL_MANGLE().
>>>
>>>  I tested it on 64-bit, but it turns out fast_bilinear crashes there
>>>  whether or not the patch is applied, unless you run it under valgrind.
>>>  Don't have time to debug it.
>>>       
>> Or maybe I do; it's just an executable stack issue. configure didn't
>> check for mmap, so this fixes it on any system with non-executable
>> stacks and mmap.
>>     
>
> Patch applied, we did sport HAVE_SYS_MMAP_H in libswscale without a
> proper check in configure.
>
> However, I assume this does not take care of the linking issue, does it?
>
>   
No, it doesn't. However, the 2 other patches (swscale-mmx2-mangle.diff 
and  local-mangle-2.diff) posted by Alexander Strange do fix the linking 
issue.

Gert