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.

###  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

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++

On OS X, you can use [Homebrew](http://brew.sh) to install the dependencies:

    $ brew install gawk gnu-sed gmp mpfr libmpc isl

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 riscv-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

### 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 riscv-unknown-linux-gnu-,
rather than the usual prefix (riscv32-... or riscv64-...).

### 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 currently only runs in
the GDB simulator, which doesn't support floating-point or Linux/glibc.  To
test GCC, run the following commands:

  ./configure --prefix=$RISCV --disable-float --disable-linux
  make check-gcc-newlib