[FFmpeg-devel] [PATCH] set HAVE_MMX2 in config.h
Wed Mar 19 06:34:23 CET 2008
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: *** [libswscale.so.0] Error 1
> > >> make: 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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