Question

I’ve been trying to cross compile libogg for armv6, armv6 and i386 using the iOS 5.1 SDK in Mountain Lion. Libogg uses autoconf, and I’ve been having pretty similar issues with a few other libraries as well. I picked up a neat little cross-compiling script from here. I had to update it a bit to find the location of the SDK’s.

GLOBAL_OUTDIR="`pwd`/dependencies"
mkdir -p $GLOBAL_OUTDIR/include $GLOBAL_OUTDIR/lib
OUTDIR="./outdir"
OGG_LIB="`pwd`/libogg-1.3.0"

IOS_BASE_SDK="5.1"
IOS_DEPLOY_TGT="3.2"

setenv_all()
{
# Add internal libs
export CFLAGS="$CFLAGS -I$GLOBAL_OUTDIR/include -L$GLOBAL_OUTDIR/lib"

export CXX="$DEVROOT/usr/bin/llvm-g++-4.2"
    export CC="$DEVROOT/usr/bin/llvm-gcc-4.2"

export LD=$DEVROOT/usr/bin/ld
export AR=$DEVROOT/usr/bin/ar
export AS=$DEVROOT/usr/bin/as
export NM=$DEVROOT/usr/bin/nm
export RANLIB=$DEVROOT/usr/bin/ranlib
export LDFLAGS="-L$SDKROOT/usr/lib/"

export CPPFLAGS=$CFLAGS
export CXXFLAGS=$CFLAGS
}

setenv_arm6()
{
unset DEVROOT SDKROOT CFLAGS CC LD CPP CXX AR AS NM CXXCPP RANLIB LDFLAGS CPPFLAGS CXXFLAGS

export DEVROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer
export SDKROOT=$DEVROOT/SDKs/iPhoneOS$IOS_BASE_SDK.sdk

export CFLAGS="-arch armv6 -pipe -no-cpp-precomp -isysroot $SDKROOT -miphoneos-version-min=$IOS_DEPLOY_TGT -I$SDKROOT/usr/include/"

setenv_all
}

setenv_arm7()
{
unset DEVROOT SDKROOT CFLAGS CC LD CPP CXX AR AS NM CXXCPP RANLIB LDFLAGS CPPFLAGS CXXFLAGS

export DEVROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer
export SDKROOT=$DEVROOT/SDKs/iPhoneOS$IOS_BASE_SDK.sdk

export CFLAGS="-arch armv7 -pipe -no-cpp-precomp -isysroot $SDKROOT -miphoneos-version-min=$IOS_DEPLOY_TGT -I$SDKROOT/usr/include/"

setenv_all
}

setenv_i386()
{
unset DEVROOT SDKROOT CFLAGS CC LD CPP CXX AR AS NM CXXCPP RANLIB LDFLAGS CPPFLAGS CXXFLAGS

export DEVROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer
export SDKROOT=$DEVROOT/SDKs/iPhoneSimulator$IOS_BASE_SDK.sdk

export CFLAGS="-arch i386 -pipe -no-cpp-precomp -isysroot $SDKROOT -miphoneos-version-min=$IOS_DEPLOY_TGT"

setenv_all
}

create_outdir_lipo()
{
for lib_i386 in `find $LOCAL_OUTDIR/i386 -name "lib*\.a"`; do
    lib_arm6=`echo $lib_i386 | sed "s/i386/arm6/g"`
    lib_arm7=`echo $lib_i386 | sed "s/i386/arm7/g"`
    lib=`echo $lib_i386 | sed "s/i386\///g"`
    lipo -arch armv6 $lib_arm6 -arch armv7 $lib_arm7 -arch i386 $lib_i386 -create -output $lib
done
}

merge_libfiles()
{
DIR=$1
LIBNAME=$2

cd $DIR
for i in `find . -name "lib*.a"`; do
    $AR -x $i
done
$AR -r $LIBNAME *.o
rm -rf *.o __*
cd -
}

And then to build the ogg library.

## libogg
cd $OGG_LIB
rm -rf $OUTPUT_DIR
mkdir -p $OUTDIR/arm6 $OUTDIR/arm7 $OUTDIR/i386

## Build for armv6
make clean 2> /dev/null
make distclean 2> /dev/null
setenv_arm6
./configure --host=arm-apple-darwin6 --enable-shared=no
make
cp /src/.libs/libogg.a $OUTDIR/arm6

## Build for armv7

make clean 2> /dev/null
make distclean 2> /dev/null
setenv_arm7
./configure --host=arm-apple-darwin7 --enable-shared=no
make
cp src/.libs/libogg.a $OUTDIR/arm7

## Build for iPhone simulator
make clean 2> /dev/null
setenv_i386
./configure
make -j4
cp src/.libs/libogg.a $OUTDIR/i386

## Stich it altogether in a fat .a file.  
create_outdir_lipo

Anyway, when building armv6 and armv7, configure finds the compiler’s and sdk’s okay , and the compiling stage goes off without a hitch. But they both fail to link. The armv7 build spits out the error.

ld: in section __TEXT,__text reloc 1: unknown relocation type 9 for architecture armv7 collect2: ld returned 1 exit status

And when I test the output binary with lipo :

$ lipo -info libogg.a
lipo: archive with no architecture specification: libogg.a (can't determine architecture for it)

What is strange is i386 seems to compile perfectly, (I’ve tried it in the simulator and all is okay).

Any suggestions on what I can do to try and fix this, or a least where I should start looking. Sorry for the massive code dumps, and thanks.

Answer 1

I was able to solve this by setting the optimization level on the compile to -O3 instead of -O4. With -O4 the files output do not seem to be recognizable to lipo (and even file reports them as data instead of Mach-O object arm).

Update: It seems quite a few people are encountering difficulty compiling Ogg Vorbis. I have made my build available. See: Precompiled Ogg Vorbis Libraries for iOS.