[FFmpeg-trac] #2659(build system:new): Compiling for i386 on 64bit OSX is hard

[FFmpeg]

#2659: Compiling for i386 on 64bit OSX is hard
-------------------------------------+-------------------------------------
             Reporter:  hendrik      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  build        |                  Version:  git-
  system                             |  master
             Keywords:  i386 OSX     |               Blocked By:
  Darwin                             |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:

 When building on OS X 10.7.5 (64bit), it is hard to build a ''small'' or
 ''shared'' 32bit version.


 How to reproduce:

 Specifying `--arch=i386` has no effect, as `configure` differentiates
 between 32 and 64 bit by compiling some code.

 Forcing 32bit via `--cc="clang -m32"` works, but then the flag `--enable-
 small` leads to a compilation error:

 {{{
 CC      libavcodec/h264_cabac.o
 In file included from libavcodec/h264_cabac.c:43:
 libavcodec/x86/h264_i386.h:137:9: error: ran out of registers during
 register allocation
         "mov %1, %6                             \n\t"
 }}}

 Since the failing code is assembler, specifying `--disable-asm` avoids the
 failure.

 What if we use gcc instead of clang? Well, that works partially. I.e. it
 does not work with shared libs enabled:

 `--enable-small --enable-shared --disable-static --arch=i386 --cc="gcc
 -m32"`

 again leads to

 {{{
 CC      libavcodec/h264_cabac.o
 cc1: error in backend: Ran out of registers during register allocation!
 make: *** [libavcodec/h264_cabac.o] Error 1
 }}}


 $ gcc --version
 i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build
 5658) (LLVM build 2336.9.00)

 $ clang --version
 Apple clang version 3.1 (tags/Apple/clang-318.0.58) (based on LLVM 3.1svn)
 Target: x86_64-apple-darwin11.4.2
 Thread model: posix

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2659>
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