Compile Swift on Mac and run on Windows

Question

How can I compile a swift file on Mac as an executable to run on Windows?

All I need is an executable that can be called from C# code.

Answer 1

If you have a proper swift library module for Windows, your swift compiler for macOS can generate object files for Windows, such as Hello.obj. Moreover, you can build the executable (ex. Hello.exe) if you have the special linker and some C/C++ runtime object files for Windows.

All you need one is follows.

1. Copy the directories to the macOS from the package for Windows.

   1) Install Swift for Windows ver-1.5 (https://swiftforwindows.codeplex.com) on Windows

   2) Copy directories to macOS from Windows

    SwiftForWindows/Swift/lib/swift  // Swift library for Windows (MinGW)
    SwiftForWindows/Swift/lib/mingw  // C/C++ runtime object files (MinGW)
   

2. Install Swift compiler for MacOS (https://swift.org/builds/swift-3.0-release/xcode/swift-3.0-RELEASE/swift-3.0-RELEASE-osx.pkg)

   You should use the same version for the library module and compiler. Use the version 3.0. Swift 3.0.1 or 3.1 will not work with SwiftForWindows-1.5.

3. Install MinGW linker with Mac Port

   1) Install Mac Port (https:// www.macports.org/install.php)

   2) $ sudo port install x86_64-w64-mingw32-binutils

   3) Create directory bfd_ld and copy /opt/local/bin/x86_64-w64-mingw32-ld and name to ld

    $ mkdir bfd_ld
    $ cp -p /opt/local/bin/x86_64-w64-mingw32-ld bfd_ld/ld
   

4. More Settings

   1) Rename the directory in macOS

    mv SwiftForWindows/Swift/lib/swift/mingw SwiftForWindows/Swift/lib/swift/windows
   

   2) Copy C runtime objects (3 files)

    cp SwiftForWindows/Swift/lib/mingw/*.o bfd_ld
   

5. Compiling

    echo "print(Hello)" > Hello.swift
    ~/Library/Developer/Toolchains/swift-3.0-RELEASE.xctoolchain/usr/bin/swiftc -target x86_64-pc-windows-gnu -resource-dir SwiftForWindows/Swift/lib/swift -tools-directory bfd_ld  -L SwiftForWindows/Swift/lib/mingw -lswiftSwiftOnoneSupport -o Hello.exe Hello.swift 
   

   This will generate Hello.exe. You can ignore the 'Warning: .drectve' message.

6. Running

   The executable file will need the DLL's in the directory 'SwiftForWindows/My Programs'.

   Copy Hello.exe to the directory in Windows and run it.

Good luck to you. Thanks.

Answer 2

If you want to run Swift code on Windows, the closest you can get is swift-windows. I have never used it but it looks like you can compile Swift 3.0 code to a Windows executable.

To download pre-built binaries, try this link. It requires Windows 10 64 bit and the Visual Studio 2015 SDK. Additionally you will have to have a cygwin or mingw environment.