On Thu, Feb 12, 2015 at 02:20:13PM +0000, Andreas Haupt wrote: > > > > > > >Michael Niedermayer <michae...@gmx.at> schrieb am 13:01 Donnerstag, > >12.Februar 2015: > > > > > >On Thu, Feb 12, 2015 at 10:56:58AM +0000, Andreas Haupt wrote: > >> Hi, > >> > >> I found an issue when linking against the ffmpeg libavcodec.a static > >> libary on armhf which can probably consider to be a bug. > >> > >> Summary of the bug: > >> When I try to build a shared library in which I include libavcodec.a I > >> receive the following linker error (on ARM plattform - banana pi board). > >> Affected versions of ffmpeg are at least 2.5.3 and git-master, affected > >> plattform is armhf (linux). > >> > >> Error message from linker: > >> > >> /home/hpt/ffmpeg/arm_gcc/2.5.3/lib/static/libavcodec.a(videodsp_armv5te.o): > >> In function `ff_prefetch_arm': > >> /root/build_ffmpeg/ffmpeg/libavcodec/arm/videodsp_armv5te.S:29:(.text+0x8): > >> relocation truncated to fit: R_ARM_THM_JUMP19 against symbol > >> `ff_prefetch_arm' defined in .text section in > >> /home/hpt/ffmpeg/arm_gcc/2.5.3/lib/static/libavcodec.a(videodsp_armv5te.o) > >> collect2: ld returned 1 exit status > >> > >> How to reproduce: > >> Use the attached cpp file to build a shared object library on arm. > >> > >> When I try to create the shared object library I get the linker error from > >> above. I used the following command to create the shared object library: > >> > >> % g++ -shared -D__STDC_CONSTANT_MACROS -o test.so > >> -I/home/hpt/ffmpeg/arm_gcc/2.5.3/include/ > >> sample_cpp_file_for_bug_reproduction.cpp > >> /home/hpt/ffmpeg/arm_gcc/2.5.3/lib/static/libavcodec.a > >> > >> There seems to be some problem in the libavcodec/arm/videodsp_armv5te.S > >> assembler file. In that file the label 'ff_prefetch_arm' (line 25) is > >> exported and further down used by a conditional near jump (line 29). The > >> near jump cannot be done if the label is exported within a shared object > >> library. That's at least the explanation I found for myself. > >> > >> I used the attached (untested) patch to fix the linker error from above. > >> As far as I can see this patch should fix the problem without any side > >> effects. At least it fixes the linker error I get. > > > >does this work too: ? > >diff --git a/libavcodec/arm/videodsp_armv5te.S > >b/libavcodec/arm/videodsp_armv5te.S > >index 55bcce5..aff1161 100644 > >--- a/libavcodec/arm/videodsp_armv5te.S > >+++ b/libavcodec/arm/videodsp_armv5te.S > >@@ -23,9 +23,10 @@ > >#include "libavutil/arm/asm.S" > > > >function ff_prefetch_arm, export=1 > > > >+1: > > subs r2, r2, #1 > > pld [r0] > > add r0, r0, r1 > >- bne X(ff_prefetch_arm) > >+ bne 1b > > bx lr > >endfunc > > > >[...] > > > >-- > >Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > > >Frequently ignored answer#1 FFmpeg bugs should be sent to our bugtracker. > >User > >questions about the command line tools should be sent to the ffmpeg-user ML. > >And questions about how to use libav* should be sent to the libav-user ML. > >_______________________________________________ > >ffmpeg-devel mailing list > >ffmpeg-devel@ffmpeg.org > >http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > > > > > > Yes, the diff you suggested does work. (They don't produce the earlier linker > error.)
patch applied thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding go out to meet it. -- Thucydides
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