[Ffmpeg-devel] [PATCH] Universal binary support for Mac OS X

[Diego Biurrun]

On Sat, Feb 04, 2006 at 07:39:27PM +0100, Dan Villiom Podlaski Christiansen wrote:
> 
> Attached below is a patch which adds a new CPU type to the FFmpeg  
> configure system, 'fat'. This is used for building a universal binary  
> on Mac OS X 10.4, which runs natively both on PowerPC and x86  
> systems. Also added is an easier way to access this this flag, '-- 
> enable-universal'. Additionally, tuning for all four CPU families  
> that Mac OS X runs on, G3, G4, G5 and Intel, is also possible by  
> specifying '--tune=all'. To my knowledge, this has no benefits beyond  
> resulting in a binary that takes four times as long to compile and is  
> four times as large as a non-fat binary, rather than the ordinary  
> universal binary which just doubles the time and space required.

I've been wondering about this fat binary thing for some time, I'm not
sure if it's a good idea in the first place.  Then again, it's probably
here to stay..

> While at it, I added the 'safe' flags that are used in Apple's -fast  
> option to GCC 4, which should generate slightly faster binaries.

Please send a separate patch for this.

> I hope the changes are acceptable for FFmpeg. If not, please tell me  
> what needs to be fixed.

I've only had a quick cursory glance at your patch.  At 48k it's quite
big and would probably be easier to review if you could break it up into
a few easier to digest pieces.


> --- configure	2 Feb 2006 13:07:29 -0000	1.242
> +++ configure	4 Feb 2006 18:06:21 -0000
> @@ -1070,7 +1117,7 @@
> -if $cc $CFLAGS $LDFLAGS $extralibs -o $TMPE $TMPC 2> /dev/null ; then
> +if $cc $CFLAGS $LDFLAGS $extralibs -o $TMPE $TMPC 2> /dev/null; then
> @@ -1475,8 +1577,9 @@
> -  echo "#define EMULATE_FAST_INT 1" >> $TMPH
> +    echo "#define EMULATE_FAST_INT 1" >> $TMPH

cosmetics

> --- libavcodec/dsputil.h	12 Jan 2006 22:43:15 -0000	1.126
> +++ libavcodec/dsputil.h	4 Feb 2006 18:06:21 -0000
> @@ -468,7 +468,7 @@
> -#if defined(HAVE_ALTIVEC) && !defined(CONFIG_DARWIN)
> +#if defined(HAVE_ALTIVEC) && defined(HAVE_ALTIVEC_H)

Won't just 'defined(HAVE_ALTIVEC_H)' suffice?

> --- libavcodec/i386/cputest.c	22 Dec 2005 01:10:09 -0000	1.16
> +++ libavcodec/i386/cputest.c	4 Feb 2006 18:06:21 -0000
> @@ -4,6 +4,8 @@
>  #include "../dsputil.h"
>  
> +#ifdef HAVE_MMX
> +
> @@ -129,3 +131,5 @@
> +
> +#endif /* HAVE_MMX */

I dislike putting #ifdef around complete file contents.  The build
system should take care of this instead and compile the file only if the
#ifdef condition is fulfilled.

Diego