Toolchain

Prebuilt toolchain

There're several options:

• Android Open Source Platform prebuilt snapshot. Click on the snapshot link to get a tar. It's about 74MB uncompressed.
• Android NDK
• Sourcery G++ arm eabi tool-chain

Assume you've chosen 1 since it is the best current option. After downloaded the toolchain to r:\prebuilt-*.tar.gz, execute:

tar xzf /mnt/r/prebuilt-*.tar.gz -C ~

A prebuilt folder will be created in user home.

Compiling your own toolchain from scratch

1. Download your device kernel, unpack this and create configs and headers:

make mapphone_defconfig
make headers_install ARCH=arm INSTALL_HDR_PATH=~/build/kern_h/

You must know, what proccessor chip you have on target device, and set optimisation options from (http://gcc.gnu.org/onlinedocs/gcc-4.4.3/gcc/ARM-Options.html#ARM-Options) For example, if you have Motorola Milestone - so processor chip is TI OMAP3430 - ARM Cortex a8 (armv7a arch) (http://en.wikipedia.org/wiki/ARM_architecture) So you need use configs with -omap3430 suffix.

Also, I recommend use kernel-...configs instead of XVilka-...configs for creating toolchain for kernel building and hacking.

Set enviroment variable for building options:

export _XXCFLAGS=" -march=armv7-a -mtune=cortex-a8 -mfpu=neon" (if you have Milestone/Droid or other device on TI OMAP3430)
export _XXCFLAGS=" -march=armv6j -mtune=arm1136jf-s" (if you have HTC Hero or other device on Quallcomm MSM 7200A)

2. Download crosstool-ng (http://ymorin.is-a-geek.org/dokuwiki/projects/crosstool), Unpack, build (you need for: make,install,bash,cut,sed,grep,gcc,awk,bison,flex,automake,libtool,stat, wget,cvs,patch,tar,gzip,bzip2,lzma,readlink,ncurses, mpfr-dev, gmp-dev)

.configure
make
make install

3. Create dir toolchain-android, cd to it and copy files: XVilka-crosstool-<suffix>.config in .config XVilka-uClibc-<suffix>.config in uClibc-0.9.30.2.config and then run:

ct-ng menuconfig

change anything, if you need, and save to .config then exec:

ct-ng build

4. Done! We have toolchain in build/x-tools. All tools have this triplet: arm-android-linux-uclibsgnueabi-* just add them in PATH

export PATH=$HOME/build/x-tools/arm-android-linux-uclibcgnueabi/bin:$PATH
export CROSS_COMPILE=arm-android-linux-uclibcgnueabi-
export KERNEL_CROSS_COMPILE=arm-android-linux-uclibcgnueabi-

So we can run arm-android-linux-uclibcgnueabi-gcc Also we have system root directory in: ~/build/x-tools/arm-android-linux-uclibcgnueabi/arm-android-linux-uclibcgnueabi/sys-root For some reasons we just copy it in ~/build/cross/sys-root

chmod +w sys-root
chmod +w sys-root/usr
chmod +w sys-root/usr/lib

Building and using tiny toolchain

For compiling some small hacking utility or kernel module you don need in whole gcc toolkit (more than 60 MB) and whole libc. So we need for something small and tiny. It can be tiny C compiler (tcc) and dietlibc You can download, unpack, copy bin files in /usr/local/bin, lib files in /usr/local/lib, tiny-root in $HOME/build. Link for downloading

If you want to know how i building it - read below:

For example we choose working directory as $HOME/build Download latest release of tiny C compiler (http://tinycc.org/) from git:

git clone git://repo.or.cz/tinycc.git $HOME/build/tinycc

Download latest release of dietlibc (http://www.fefe.de/dietlibc/) from cvs: <syntaxhiglight lang="bash"> cvs -d :pserver:cvs@cvs.fefe.de:/cvs -z9 co $HOME/build/dietlibc </syntaxhighlight> After this we need to build tcc:

cd $HOME/build/tinycc
./configure --enable-cross --prefix=$HOME/build/tiny-toolchain
make
make install

So we have this tools in $HOME/build/tiny-toolchain/bin:

arm-eabi-tcc
arm-fpa-ld-tcc
arm-fpa-tcc
arm-vfp-tcc
c67-tcc
i386-win32-tcc
tcc
x86_64-tcc
x86_64-win32-tcc

Add them in enviroment variable PATH for easy executing:

export PATH=$HOME/build/tiny-toolchain/bin:$PATH

But also we need a C library. So make the "target root" directory: <syntaxhiglight lang="bash"> mkdir $HOME/build/tiny-root </syntaxhighlight> Building dietlibc:

cd $HOME/build/dietlibc
make prefix=$HOME/build/tiny-root
make prefix=$HOME/build/tiny-root ARCH=arm CROSS=arm-android-linux-uclibcgnueabi-
make install-headers prefix=$HOME/build/tiny-root ARCH=arm CROSS=arm-android-linux-uclibcgnueabi-
make install-bin prefix=$HOME/build/tiny-root ARCH=arm CROSS=arm-android-linux-uclibcgnueabi-

Prepare "target root" directory:

ln -s $HOME/build/tiny-root/lib-arm $HOME/build/tiny-root/lib
cp $HOME/build/tiny-toolchain/include/* $HOME/build/tiny-root/include/
cp $HOME/build/tiny-toolchain/lib/* $HOME/build/tiny-root/lib/

Also, for kernel development we need for kernel headers:

cd /path/to/you/kernel/sources
make headers_install ARCH=arm INSTALL_HDR_PATH=$HOME/build/tiny-root/include

So, we have all needed libraries and headers in $HOME/build/tiny-root You can use tcc for compiling your small utilities, for example by this command:

arm-eabi-tcc -nostdinc -nostdlib -I$HOME/build/tiny-root/include -L$HOME/build/tiny-root/lib -o example example.c

Enjoy!