ffmpeg does not build with gcc-4.7

[Julian Sikorski]

Hi,

I have recently tried to build an mplayer snapshot, which pulls ffmpeg git. Unfortunately, it is impossible to build it with gcc-4.7 prerelease, which Fedora switched to:

ffmpeg/libavcodec/libavcodec.a(ffv1.o): In function `encode_init':
/builddir/build/BUILD/mplayer-export-2012-02-26/ffmpeg/libavcodec/ffv1.c:1041: undefined reference to `__builtin_iround'
collect2: error: ld returned 1 exit status
make: *** [mplayer] Error 1
make: *** Waiting for unfinished jobs....
ffmpeg/libavcodec/libavcodec.a(ffv1.o): In function `encode_init':
/builddir/build/BUILD/mplayer-export-2012-02-26/ffmpeg/libavcodec/ffv1.c:1041: undefined reference to `__builtin_iround'
collect2: error: ld returned 1 exit status
make: *** [mencoder] Error 1

Any ideas on how to fix this? Or is it perhaps a gcc error? Cheers.

[Julian Sikorski]

full build log

[Carl Eugen Hoyos]

Could you confirm that the problem is also reproducible with current FFmpeg git head and ./configure --cc=... && make?
If yes, please run make twice and provide the complete, uncut output of a subsequent make V=1.

[Julian Sikorski]

Hmm, it seems ffmpeg itself builds fine (even when make is invoked from within the copy configured by mplayer. Where should I report it then, mplayer-users or mplayer bugzilla?

[Julian Sikorski]

​http://bugzilla.mplayerhq.hu/show_bug.cgi?id=2047

[Carl Eugen Hoyos]

What is the difference between the config.h (and config.mak) files?

[Julian Sikorski]

Which ones?

[Carl Eugen Hoyos]

You will find a config.h (and a config.mak) file in both your MPlayer and your FFmpeg build directory. Comparing them may explain why the MPlayer build fails.

[Julian Sikorski]

The ones in ffmpeg subdir just include the toplevel ones:

#include "../config.h"

ifndef FFMPEG_CONFIG_MAK
FFMPEG_CONFIG_MAK = 1
include ../config.mak
endif # FFMPEG_CONFIG_MAK

[Carl Eugen Hoyos]

1.
configure MPlayer with ./configure: You will find a config.h and a config.mak file in the MPlayer root directory. I assume building with "make" fails with above error (builtin_iround).
2.
Download current FFmpeg git master and run ./configure. I assume building with "make" does not fail. Now find config.h (and config.mak) in the FFmpeg root directory and compare it with config.h from MPlayer root directory.
If building current FFmpeg fails (you may just have tested "cd ffmpeg && make" which does not link anything and therefore cannot fail as above), then please run make twice for FFmpeg and post the complete, uncut output of a subsequent run of "make V=1" and of "gcc -v" (and consider closing the MPlayer bug you opened).

[Julian Sikorski]

config.h differences

[Julian Sikorski]

config.mak differences

[Julian Sikorski]

The files are quite different to figure anything out immediately.
ffmpeg git master from yesterday builds fine on its own, including linkage.
mplayer svn w/ ffmpeg git master builds fine on Fedora 16 (gcc-4.6), it fails on Fedora 17 only.
I hope it clears the current situation.

[Carl Eugen Hoyos]

Is the compilation problem also reproducible if you build MPlayer with "./configure && make" - the only supported configuration afaict?

[Julian Sikorski]

Yes, it does. I tried with a newer checkout (2012-03-01) and it is still the same.

[Julian Sikorski]

build log with no additional switches passed to ./configure

[Julian Sikorski]

--disable-mencoder works around the problem.

[Julian Sikorski]

configuration diff between --disable-mencoder and no configure switches

[Carl Eugen Hoyos]

How does the comparison between config.h and config.mak look now?

[Julian Sikorski]

config.h differences

[Julian Sikorski]

config.mak differences

[Julian Sikorski]

Here you go. I did:
$ ./configure && make -j8
$ cd ffmpeg
$ ./configure && make -j8

[ojab]

GCC bug, fixed ​http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52592
This ticket can be closed.

[Carl Eugen Hoyos]

Thank you for the information!