Bare metal RISC-V GCC 9.3.0 cross compiler instructions

Introduction

We'll build a GCC 9.2.0 targeting bare metal RISC-V. Many RISC-V tools expect a $RISCV variable pointing at the toolchain, so we can't use split --prefix and --bindir as we usually use.

Create directories

cd $HOME
mkdir -p src obj/{binutils-build,gcc-build,gdb-build,newlib-build}

Get GCC, GDB and binutils

curl https://ftp.gnu.org/gnu/binutils/binutils-2.33.1.tar.gz | tar -C $HOME/src -xf -
curl https://ftp.gnu.org/gnu/gdb/gdb-8.3.tar.gz | tar -C $HOME/src -xf -
curl https://ftp.gnu.org/gnu/gcc/gcc-9.2.0/gcc-9.2.0.tar.gz | tar -C $HOME/src -xf -
curl ftp://sourceware.org/pub/newlib/newlib-3.1.0.tar.gz | tar -C $HOME/src -xf -

Download prerequisites

cd $HOME/src/gcc-9.2.0
./contrib/download_prerequisites

Build and install binutils

cd $HOME/obj/binutils-build
../../src/binutils-2.33.1/configure --prefix $HOME/riscv --target riscv64-unknown-elf --enable-multilib
make -j8 && make install

Build and install gdb

cd $HOME/obj/gdb-build
../../src/gdb-8.3/configure --prefix $HOME/riscv --target riscv64-unknown-elf --enable-multilib
make -j8 && make install

Build and install bare metal gcc

cd $HOME/obj/gcc-build
../../src/gcc-9.2.0/configure --prefix $HOME/riscv --target riscv64-unknown-elf --enable-multilib --enable-languages=c --with-gnu-as --with-gnu-ld --without-headers --with-newlib
make -j8 all-gcc && make install-gcc

Build and install newlib

cd $HOME/obj/newlib-build
../../src/newlib-3.1.0/configure --prefix $HOME/riscv --target riscv64-unknown-elf --enable-multilib
make -j8 all && make install

Build and install newlib gcc

rm -rf $HOME/obj/gcc-build && mkdir -p $HOME/obj/gcc-build
cd $HOME/obj/gcc-build
../../src/gcc-9.2.0/configure --prefix $HOME/riscv --target riscv64-unknown-elf --enable-multilib --enable-languages=c --with-gnu-as --with-gnu-ld --with-newlib
make -j8 all && make install

Build and install riscv-openocd

cd $HOME/src
git clone --recursive git@github.com:riscv/riscv-openocd.git
cd $HOME/src/riscv-openocd
# brew install pkg-config libtool automake autoconf # required by bootstrap
./bootstrap
./configure --prefix=$HOME/riscv --enable-remote-bitbang --enable-jtag_vpi
make -j8 && make install

Add tools to PATH and set RISCV

printf "PATH=$HOME/riscv/bin:$PATH\nRISCV=$HOME/riscv\nexport RISCV\n" >> $HOME/lib/profile.local