README.md

Building Swift on ARM

A few, very simple, bash scripts to clone, configure and build Swift 4.1.3 on ARM devices.

Supported Architectures

• ✅ ARMv7 (RaspberryPi 2/3, ODroid, CHIP, etc...)
• ✅ ARMv6 (Original RaspberryPi, Pi Zero, etc... )
• ✅ aarch64 (Pine64, etc...)

Prebuilt binaries

Swift 4.1.3 armv7(RaspberryPi 2/3) for Ubuntu Mate 16.04.x is available here or here for Raspbian Stretch. Binaries for the original RaspberryPi and the various versions of the RaspberryPi Zero running Raspbian are here.

See the required dependencies below (clang and a few other packages).

Instructions

For the latest updates on Swift on ARM, check out my blog here.

Check out Helge Heß's project dockSwiftOnARM to build Swift in a Docker container or to build a cross-compiling toolchain that will allow you to build arm binaries directly from your Mac using a precompiled swiftc for ARM.

The scripts:

• clone.sh - Install dependencies and clones the main Swift repository and all the related projects

• checkoutRelease.sh - Resets all repos, updates them, checks out a specific tag (4.1.3 at the moment) and apply the patches

• build.sh - Build

• clean.sh - Clean all build artifacts

Building instructions

First of all, use a suitably sized sd-card, at least 16Gb in size.

Configure a swap file of at least 3Gb, on Ubuntu:

sudo fallocate -l 3G swapfile
sudo chmod 600 swapfile
sudo mkswap swapfile
sudo swapon swapfile

You'll need to manually enable the swap file with swapon each time you reboot the RaspberryPi (or the system will just run without swap).

On Raspbian, open /etc/dphys-swapfile and edit:

CONF_SWAPSIZE=2048

Save the file and:

sudo /etc/init.d/dphys-swapfile stop
sudo /etc/init.d/dphys-swapfile start

Now, call the included scripts as follows:

1. Launch clone.sh that will install the required dependencies (git cmake ninja-build clang-3.8 python uuid-dev libicu-dev icu-devtools libbsd-dev libedit-dev libxml2-dev libsqlite3-dev swig libpython-dev libncurses5-dev pkg-config libblocksruntime-dev libcurl4-openssl-dev autoconf libtool systemtap-sdt-dev libcurl4-openssl-dev libz-dev), fix clang links and clone apple/swift with all its dependecies.

2. Run checkoutRelease.sh that will select the current release (4.1.1) and apply the needed patches. These patches cover the basic Raspi2/3 with Xenial case, but I've had many reports of successful build on different setups, but beware, additional patches could be needed on different boards/OSs.

3. Once done, start the build with build.sh.

4. Once the build completes a few hours later, you'll have a swift-4.1.1.tgz archive containing the whole Swift compiler distribution. Once decompressed you'll find the Swift binaries under usr/bin.

I recommend to perform all these operations in a permanent background tmux or screen session (CTRL+B d to detach from the session and tmux a to reattach to it when you ssh again into the RaspberryPi).

Additional steps could be required in some cases (on a RaspberryPi 1 or for Raspbian) check the latest ARM posts on my blog for additional info.

To build a different release than the one currently configured in the script, open checkoutRelease.sh and build.sh and modify the variables on top, with the branch name for the release and the release name for the tgz respectively.

Dependencies

If you plan to use one of the provided prebuilt binaries, you'll need the install the following dependencies dependecies:

sudo apt install clang-3.8 libicu-dev libcurl4-nss-dev

REPL Issues

Since the first releases of Swift on ARM32, the REPL has never been available on this platform, but that doesn't impact the compiler itself. Considering this, as you would expect, launching swift without parameters will result in an error instead of the REPL prompt.

Acknowledgments

We wouldn't have Swift on ARM and most of the patches included on buildSwiftOnARM without the work done by these developers:

• @Kaiede
• @chnmrc
• @jasonm128
• @hpux735
• @iachievedit

The community can be reached at the swift-arm Slack channel.

Previous Releases

You can compile old releases checking out the specific tag:

• Swift 4.1.3
• Swift 3.1.1
• Swift 3.1
• Swift 3.0.2