RISC-V GNU Compiler Toolchain
This is the RISC-V C and C++ cross-compiler. It supports two build modes: a generic ELF/Newlib toolchain and a more sophisticated Linux-ELF/glibc toolchain.
If you are looking for how to build toolchain for Nuclei RISC-V Processor, please check Build RISC-V GNU Toolchain For Nuclei
Getting the sources
This repository uses submodules. You need the --recursive option to fetch the submodules automatically
$ git clone --recursive https://github.com/riscv/riscv-gnu-toolchain
Alternatively :
$ git clone https://github.com/riscv/riscv-gnu-toolchain
$ cd riscv-gnu-toolchain
$ git submodule update --init --recursive
Prerequisites
Several standard packages are needed to build the toolchain. On Ubuntu, executing the following command should suffice:
$ sudo apt-get install autoconf automake autotools-dev curl libmpc-dev libmpfr-dev libgmp-dev gawk build-essential bison flex texinfo gperf libtool patchutils bc zlib1g-dev libexpat-dev
On Fedora/CentOS/RHEL OS, executing the following command should suffice:
$ sudo yum install autoconf automake libmpc-devel mpfr-devel gmp-devel gawk bison flex texinfo patchutils gcc gcc-c++ zlib-devel expat-devel
On OS X, you can use Homebrew to install the dependencies:
$ brew install gawk gnu-sed gmp mpfr libmpc isl zlib expat
To build the glibc (Linux) on OS X, you will need to build within a case-sensitive file system. The simplest approach is to create and mount a new disk image with a case sensitive format. Make sure that the mount point does not contain spaces. This is not necessary to build newlib or gcc itself on OS X.
This process will start by downloading about 200 MiB of upstream sources, then will patch, build, and install the toolchain. If a local cache of the upstream sources exists in $(DISTDIR), it will be used; the default location is /var/cache/distfiles. Your computer will need about 8 GiB of disk space to complete the process.
Installation (Newlib)
To build the Newlib cross-compiler, pick an install path. If you choose,
say, /opt/riscv, then add /opt/riscv/bin to your PATH now. Then, simply
run the following command:
./configure --prefix=/opt/riscv
make
You should now be able to use riscv64-unknown-elf-gcc and its cousins.
Installation (Linux)
To build the Linux cross-compiler, pick an install path. If you choose,
say, /opt/riscv, then add /opt/riscv/bin to your PATH now. Then, simply
run the following command:
./configure --prefix=/opt/riscv
make linux
The build defaults to targetting RV64GC (64-bit), even on a 32-bit build environment. To build the 32-bit RV32GC toolchain, use:
./configure --prefix=/opt/riscv --with-arch=rv32gc --with-abi=ilp32d
make linux
Supported architectures are rv32i or rv64i plus standard extensions (a)tomics, (m)ultiplication and division, (f)loat, (d)ouble, or (g)eneral for MAFD.
Supported ABIs are ilp32 (32-bit soft-float), ilp32d (32-bit hard-float), ilp32f (32-bit with single-precision in registers and double in memory, niche use only), lp64 lp64f lp64d (same but with 64-bit long and pointers).
Installation (Linux multilib)
To build the Linux cross-compiler with support for both 32-bit and 64-bit, run the following commands:
./configure --prefix=/opt/riscv --enable-multilib
make linux
The multilib compiler will have the prefix riscv64-unknown-linux-gnu-, but will be able to target both 32-bit and 64-bit systems.
Advanced Options
There are a number of additional options that may be passed to configure. See './configure --help' for more details.
Test Suite
The DejaGnu test suite has been ported to RISC-V. This can run with GDB simulator for elf toolchain or Qemu for linux toolchain, and GDB simulator doesn't support floating-point. To test GCC, run the following commands:
./configure --prefix=$RISCV --disable-linux --with-arch=rv64ima # or --with-arch=rv32ima
make newlib
make report-newlib
./configure --prefix=$RISCV
make linux
make report-linux