If you can't run on the prebuilt toolchain on your system or want to do a development build, you can build the toolchain from scratch. This is not that spectacular nowadays and can take like an hour at maximum. Nevertheless you need some basic understanding of how a build GNU process works.
First of all you need the development packages of the mpfr, gmp, mpc and zlib libraries on your computer, along with of course the basic GCC toolchain for your host. On a recent Debian/Ubuntu this is done with:
sudo apt-get install git libgmp-dev libmpfr-dev libmpc-dev \
zlib1g-dev texinfo build-essential flex bison
Next you need to setup the environment for your build (PREFIX to ease the execution of the code below and PATH because later stages need the results from previous stages):
export PREFIX=/opt/toolchains/or1k-elf
export PATH=$PATH:$PREFIX/bin
Next you need the git repositories. Of course you can also use the release snapshot tarballs of the releases. To build from the upstream repositories:
git clone git://sourceware.org/git/binutils-gdb.git binutils
git clone https://github.com/openrisc/or1k-gcc.git gcc
git clone git://sourceware.org/git/newlib-cygwin.git newlib
git clone https://github.com/openrisc/binutils-gdb.git gdb
In case you want to build from the development sources you need to check out the following set of repositories:
git clone https://github.com/openrisc/binutils-gdb.git binutils
git clone https://github.com/openrisc/or1k-gcc.git gcc
git clone https://github.com/openrisc/newlib.git
ln -s binutils gdb
Those repositories differ from the upstream repositories in that there might be changes in the upstream code that have not yet been merged, but also architecture specific code that is not yet in the upstream distribution.
Of course you may desire to check out a repository for a certain release by checkout of the respective git tag. Once the repositories are in your temporary compilation repository, you need to execute the following sequence to build the entire toolchain.
Note: In case you want to copy the toolchain to other computers with a different distribution or want to build a release version, it is preferable not to dynamically link gcc against the installed versions of `libgmp`, `libmpfr` and `libmpc`. Instead you then extract the sources of the libraries into the gcc source tree. The build when then pick those sources up and compile them into gcc. For example:
wget https://gmplib.org/download/gmp/gmp-6.1.0.tar.xz
tar -xf gmp-6.1.0.tar.xz
ln -s ../gmp-6.1.0 gcc/gmp
wget ftp://ftp.gnu.org/gnu/mpc/mpc-1.0.3.tar.gz
tar -xzf mpc-1.0.3.tar.gz
ln -s ../mpc-1.0.3 gcc/mpc
wget http://www.mpfr.org/mpfr-current/mpfr-3.1.6.tar.xz
tar -xf mpfr-3.1.6.tar.xz
ln -s ../mpfr-3.1.6 gcc/mpfrThe GNU binutils contain the assembler, linker, objdump and a lot more programs to handle the binary files for a certain architecture. Those can be directly built standalone:
mkdir build-binutils; cd build-binutils
../binutils/configure --target=or1k-elf --prefix=$PREFIX --disable-itcl --disable-tk --disable-tcl --disable-winsup --disable-gdbtk --disable-libgui --disable-rda --disable-sid --disable-sim --disable-gdb --with-sysroot --disable-newlib --disable-libgloss --with-system-zlib
make
make install
cd ..
GCC is built in two stages. First we now need the basic C compiler to build the C library in the next step:
mkdir build-gcc-stage1; cd build-gcc-stage1
../gcc/configure --target=or1k-elf --prefix=$PREFIX --enable-languages=c --disable-shared --disable-libssp
make
make install
cd ..
Now we can build the newlib C library:
mkdir build-newlib; cd build-newlib
../newlib/configure --target=or1k-elf --prefix=$PREFIX
make
make install
cd ..
Now we can build the entire GCC and tell it about using newlib:
mkdir build-gcc-stage2; cd build-gcc-stage2
../gcc/configure --target=or1k-elf --prefix=$PREFIX --enable-languages=c,c++ --disable-shared --disable-libssp --with-newlib
make
make install
cd ..
In the last step, we can now build gdb for our architecture:
mkdir build-gdb; cd build-gdb
../gdb/configure --target=or1k-elf --prefix=$PREFIX --disable-itcl --disable-tk --disable-tcl --disable-winsup --disable-gdbtk --disable-libgui --disable-rda --disable-sid --with-sysroot --disable-newlib --disable-libgloss --disable-gas --disable-ld --disable-binutils --disable-gprof --with-system-zlib
make
make install
cd ..
Now you are done and have the binaries or1k-elf-gcc, or1k-elf-gdb, or1k-elf-ld etc. in $PREFIX/bin.