Opened 4 years ago

Closed 4 years ago

#1241 closed defect (fixed)

ffmpeg build is trying to compile 'neon' although this instruction set is disabled @ ./configure ( '--disable-neon' )

Reported by: nadav Owned by:
Priority: normal Component: build system
Version: git-master Keywords: arm neon build
Cc: notzed Blocked By:
Blocking: Reproduced by developer: yes
Analyzed by developer: no

Description

Environment

OS Ubuntu 11.10
RELEASE 0.10.2.git
Platform Android
neon --disable-neon
optimizations --disable-optimizations

Problem

Problem ffmpeg build is trying to compile 'neon' although this instruction set is disabled @ ./configure ( '--disable-neon' )
Symptom libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_vert_neon' ...
Analysis The problem is in affect ONLY when compiling with '--disable-optimizations', going though the code, at multiple places the line 'if (HAVE_NEON)' is used, my assumption is that when the optimizer is on, the 'if (HAVE_NEON)' phrases are omitted from compilation, and, when the optimization is disabled, they ( neon phrases ) are not, and thus, the import table for neon instructions @ 'if (false)' phrases is added the neon instructions ( although they are not used by the code ), and this, leads to the undefined reference linker error.

Attachments (3)

patchneondsp.diff (2.4 KB) - added by cehoyos 4 years ago.
1241-new.diff (1.9 KB) - added by notzed 4 years ago.
similar patch against git head
patchneondsp2.diff (2.0 KB) - added by cehoyos 4 years ago.

Download all attachments as: .zip

Change History (17)

comment:1 Changed 4 years ago by nadav

One additional comment, using '--disable-optimizations' with ffmpeg@Android is mandatory so I'll B able to step through ffmpeg code while debugging on the device.

comment:2 Changed 4 years ago by cehoyos

  • Component changed from avcodec to build system
  • Keywords arm added

Which compiler and version are you using?

The error message you provide does not match the configure options you mentioned.

Please provide your configure line and please run make, run make again, then run "make V=1" and post the complete output (please do not post the complete output of the first make run).

comment:3 Changed 4 years ago by nadav

compiler

The one provided with NDK7B ( arm-linux-androideabi-4.4.3 )

configure

../../Multimedia/ffmpeg/configure \
--logfile="configure.log" \
--cross-prefix=arm-linux-androideabi- \
--arch=arm \
--target-os=linux \
--disable-everything \
--disable-pthreads \
--disable-stripping \
--enable-debug=3 \
--enable-version3 \
--enable-libx264 \
--enable-demuxer=mov \
--enable-demuxer=rtsp \
--enable-muxer=asf \
--enable-muxer=asf_stream \
--enable-muxer=mov \
--enable-muxer=mp4 \
--enable-muxer=ffm \
--enable-encoder=h264 \
--enable-decoder=h264 \
--enable-demuxer=ffm \
--enable-parser=h264 \
--enable-protocol=file \
--enable-protocol=rtp \
--enable-nonfree \
--enable-gpl \
--enable-postproc \
--extra-cflags="-I/home/nadav/workspace/Android/x264 -I/home/nadav/workspace/Multimedia/x264 -gstabs+" \
--extra-ldflags="-L/home/nadav/workspace/Android/x264" \
--enable-static \
--enable-shared \
--disable-neon \
--disable-optimizations

make V=1

arm-linux-androideabi-gcc -Llibavcodec -Llibavdevice -Llibavfilter -Llibavformat -Llibavutil -Llibpostproc -Llibswscale -Llibswresample -L/home/nadav/workspace/Android/x264 -Wl,--as-needed -Wl,--warn-common -Wl,-rpath-link=libpostproc:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil -o ffmpeg_g ffmpeg.o cmdutils.o -lavdevice -lavfilter -lavformat -lavcodec -lpostproc -lswresample -lswscale -lavutil -lx264 -lm -lz

undefined reference

libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_vert_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_l0t_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_biweight_h264_pixels_4_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_left_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct_add16_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct8_add4_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_0l0_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_v_loop_filter_luma_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_top_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_biweight_h264_pixels_16_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_0lt_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_hor_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_128_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_plane_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_hor_neon'
libavcodec/libavcodec.so: undefined reference to `ff_weight_h264_pixels_8_neon'
libavcodec/libavcodec.so: undefined reference to `ff_biweight_h264_pixels_8_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_v_loop_filter_chroma_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_top_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_weight_h264_pixels_4_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_left_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_128_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_h_loop_filter_luma_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_vert_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct_add8_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred8x8_l00_dc_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct8_add_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct_add16intra_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct_dc_add_neon'
libavcodec/libavcodec.so: undefined reference to `ff_pred16x16_plane_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct_add_neon'
libavcodec/libavcodec.so: undefined reference to `ff_weight_h264_pixels_16_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_h_loop_filter_chroma_neon'
libavcodec/libavcodec.so: undefined reference to `ff_h264_idct8_dc_add_neon'

Changed 4 years ago by cehoyos

comment:4 Changed 4 years ago by cehoyos

Could you test if attached patch makes any difference?

comment:5 Changed 4 years ago by nadav

~/workspace/Multimedia/ffmpeg$ patch -p1 -i patchneondsp.diff
patching file libavcodec/arm/h264dsp_init_arm.c
Hunk #1 succeeded at 68 (offset 1 line).
Hunk #2 FAILED at 96.
1 out of 2 hunks FAILED -- saving rejects to file libavcodec/arm/h264dsp_init_arm.c.rej
patching file libavcodec/arm/h264pred_init_arm.c
Hunk #1 succeeded at 43 (offset 1 line).
Hunk #2 FAILED at 74.
1 out of 2 hunks FAILED -- saving rejects to file libavcodec/arm/h264pred_init_arm.c.rej

Also, attached, 'h264dsp_init_arm.c.rej' and 'h264pred_init_arm.c.rej'

comment:6 Changed 4 years ago by cehoyos

Please test current git head with (and without) the patch.

comment:7 Changed 4 years ago by cehoyos

Could you test if this problem is still reproducible?
Build problems can be important, but this is unlikely to get fixed without some help (I don't have an arm environment).

Changed 4 years ago by notzed

similar patch against git head

comment:8 follow-up: Changed 4 years ago by notzed

with this patch applied, --enable-optimize works, --enable-optimise --disable-neon also works.

This is the config line, which is about the simplest I could manage and have it build:

--prefix=/home/notzed/svn/ffmpeg-build/build/armeabi-v7a --cross-prefix=/usr/local/android-ndk-r7c/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi- --enable-cross-compile --target-os=linux --sysroot=/usr/local/android-ndk-r7c/platforms/android-8/arch-arm/ --arch=arm --disable-optimizations

Version 0, edited 4 years ago by notzed (next)

Changed 4 years ago by cehoyos

comment:9 in reply to: ↑ 8 Changed 4 years ago by cehoyos

  • Cc notzed added

Replying to notzed:

with this patch applied, --enable-optimize works, --enable-optimise --disable-neon also works.

--enable-optimize ?

Your patch adds an externally visible symbol, does my new patch work for you?

comment:10 Changed 4 years ago by notzed

Sure it does - it was copying the patch you provided: https://ffmpeg.org/trac/ffmpeg/attachment/ticket/1241/patchneondsp.diff

The new patch also works.

comment:11 Changed 4 years ago by michael

Which patch fixes what ?
ive tested several patches and configurations on NDK and none fixed anything.

comment:12 Changed 4 years ago by michael

  • Summary changed from ffmpeg to ffmpeg build is trying to compile 'neon' although this instruction set is disabled @ ./configure ( '--disable-neon' )

update summary based on dscription of the original report

comment:13 follow-up: Changed 4 years ago by notzed

Sorry I mean to update this a while ago but I couldn't find the bug number.

Without the patchneondsp2 diff, the command line i gave fails to build, with those neon_* symbols missing. With the patch it succeeds.

But I actually wanted neon turned on, so my case was slightly different, sorry if i just confused the matter by trying to help.

comment:14 in reply to: ↑ 13 Changed 4 years ago by michael

  • Keywords neon build added
  • Reproduced by developer set
  • Resolution set to fixed
  • Status changed from new to closed
  • Version changed from unspecified to git-master

Replying to notzed:

Without the patchneondsp2 diff, the command line i gave fails to build, with those neon_* symbols missing. With the patch it succeeds.

thanks, ive been able to reproduce and fix the issue

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