> > >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.) Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel