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.
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