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

[Alexander Strange]

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.
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