HOWTO build the toolchain

• Ensure that you have a copy of bison and flex installed on your system. All major systems should have these tools installed or available in package management systems.

$ bison --version
GNU Bison version 1.28
$ flex --version
flex version 2.5.4

• Check out a copy of LLVM SVN, and build a release build (as opposed to a debug one). Currently, due to Issue 70, we are limited to revision 42498.

$ svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm-svn -r 42498
$ pushd llvm-svn
$ ./configure --enable-optimized
$ make ENABLE_OPTIMIZED=1
$ sudo make install
$ LLVMOBJDIR=`pwd`
$ popd

• Check out a copy of the iphone-dev SVN repository.

$ svn checkout http://iphone-dev.googlecode.com/svn/trunk/ iphone-dev
$ pushd iphone-dev

• Make a directory to hold the toolchain.

$ sudo mkdir /usr/local/arm-apple-darwin

• Build odcctools.

$ mkdir -p build/odcctools
$ pushd build/odcctools
$ ../../odcctools/configure --target=arm-apple-darwin --disable-ld64
$ make
$ sudo make install
$ popd

• Get a copy of the iPhone root filesystem. This is usually obtained by decrypting and extracting the iPhone restore software using these tools, but there are many other methods to obtain this, including simply using scp to download all the files from the iPhone over Wi-Fi. Unpack the root filesystem somewhere, and set the environment variable $HEAVENLY to its path.

$ HEAVENLY=/usr/local/share/iphone-filesystem

• Install the iPhone headers to the appropriate place. If you aren't on Mac OS X, replace the /Developer/SDKs/MacOSX10.4u.sdk path with the full path to the unpacked Mac OS X 10.4 Universal SDK. If you don't have a copy of this, see below.

$ pushd include
$ ./configure --with-macosx-sdk=/Developer/SDKs/MacOSX10.4u.sdk
$ sudo bash install-headers.sh
$ popd

• Install csu, which includes crt1.o, dylib1.o, and bundle1.o. Don't rebuild them from source, as this requires a working cross-GCC, which you don't have yet (and the build-from-source process for csu is broken right now anyway). Binaries are provided for this reason.

$ mkdir -p build/csu
$ pushd build/csu
$ ../../csu/configure --host=arm-apple-darwin
$ sudo make install
$ popd

• Only if you are compiling on leopard 10.5. This is an ugly workaround and compiling with the resulting toolchain will give you a warning.

$ mv llvm-gcc-4.0-iphone/configure llvm-gcc-4.0-iphone/configure.old
$ sed 's/^FLAGS_FOR_TARGET=$/FLAGS_FOR_TARGET=${FLAGS_FOR_TARGET-}/g' \
llvm-gcc-4.0-iphone/configure.old > llvm-gcc-4.0-iphone/configure
$ export FLAGS_FOR_TARGET="-mmacosx-version-min=10.1"
$ sudo ln -s /usr/local/arm-apple-darwin/lib/crt1.o \
/usr/local/arm-apple-darwin/lib/crt1.10.5.o

• Configure and make LLVM-GCC. Make sure that $LLVMOBJDIR and $HEAVENLY are set per the instructions above.

$ mkdir -p build/llvm-gcc-4.0-iphone
$ pushd build/llvm-gcc-4.0-iphone
$ ../../llvm-gcc-4.0-iphone/configure --enable-llvm=`llvm-config --obj-root` \
--enable-languages=c,c++,objc,obj-c++ --target=arm-apple-darwin --enable-sjlj-exceptions \
--with-heavenly=$HEAVENLY --with-as=/usr/local/bin/arm-apple-darwin-as \
--with-ld=/usr/local/bin/arm-apple-darwin-ld --enable-wchar_t=no
$ make LLVM_VERSION_INFO=2.0-svn-iphone-dev-0.3-svn
$ sudo make install
$ popd
$ popd

• You're done. Have fun!