GitHub Action for Swift armhf (armv6 & armv7)

This repo contains a GitHub action to download and install Swift built for Linux armhf (armv6 and armv7) distributions. This action is easily integrated into an existing CI and provides destination files that can be used to cross-compile any Swift package for the desired target.

The SDKs that are built and hosted on swift-armhf are downloaded and installed. The following versions are supported:

Architecture	Swift Versions	Supported Distributions
armv6	Swift 6.0 and later	raspios-bullseye raspios-bookworm raspios-trixie
armv7	Swift 5.10 and later	debian-bullseye debian-bookworm debian-trixie ubuntu-focal ubuntu-jammy ubuntu-noble raspios-bullseye raspios-bookworm raspios-trixie

The action is compatible with and has been tested to work with the following runners/environments:

• container: swift:<swift_version>
• x86_64 runners: ubuntu-20.04, ubuntu-22.04, ubuntu-24.04, ubuntu-latest
• arm64 runners: ubuntu-22.04-arm, ubuntu-24.04-arm

Notes:

1. In order to use the SDKs, the version of Swift that is installed on the host MUST match the version of the SDK that is installed. I.e., ensure that Swift 6.1.2 is installed in the host when installing any 6.1.2 SDK for armhf.
2. This action requires root access to install the wget dependency for downloading the SDK, and root access for installing the SDK to /opt.

Usage

To start using the action, include swift-embedded-linux/armhf-action@main in a step:

    - uses: swift-embedded-linux/armhf-action@main
      name: Install armhf SDK
      id: armhf-sdk
      with:
        swift-version: 6.2
        distribution: debian-bookworm
        arch: armv7

See action.yml for a complete list of supported Swift versions and distributions.

Warning

Cross-compiling Swift modules with Swift 6.2 is broken when .Cxx interop is enabled due to this bug: swiftlang/swift#83915. Some targets may work, but if you need C++ interop you may want to skip this release. The issue is fixed in Swift 6.2.1.

The action provides the following outputs that can be used from other steps:

• sdk_name: Name of the SDK that is installed to /opt.
• destination_json: The destination.json file to use to dynamically cross-compile.
• destination_static_json: The destination.json file to use to statically cross-compile.

To cross-compile a Swift package dynamically using the the destination_json file, use it like this:

    - name: Build (Include Tests)
      run: swift build --build-tests --destination ${{ steps.armhf-sdk.outputs.destination_json }}

Static linking can only be done against executable or library targets. Both the XCTest and Testing modules are NOT statically compiled in the provided armhf SDKs, so tests cannot be built using static linking. To statically link a target, use destination_static_json:

    - name: Static Build
      run: swift build -c release --destination ${{ steps.armhf-sdk.outputs.destination_static_json }} --static-swift-stdlib