This document describes how to cross compile Swift for Windows on a non-Windows host. For more context on the status of Swift on Windows in general, see Getting Started with Swift on Windows
Building for Windows requires that the Visual Studio environment variables are setup similar to the values on Windows. Currently, the runtime has been tested to build against the Windows 10 SDK at revision 10.10.586.
# Visual Studio 2015 does not have VCToolsInstallDir, use VCINSTALLDIR's value export UCRTVersion=10.0.10586.0 export UniversalCRTSdkDir=".../Windows Kits/10" export VCToolsInstallDir=".../Microsoft Visual Studio/2017/Community"
ucrt.modulemap located at
swift/stdlib/public/Platform/ucrt.modulemap needs to be copied into
visualc.modulemap located at
swift/stdlib/public/Platform/visualc.modulemap needs to be copied into
Ensure that we use the tools from the just built LLVM and
clang tools to build the Windows SDK. You will need to pass a few extra options to cmake via the
build-script invocation to achieve this. You will need to expand out the path where
llvm-ranlib are built. These are needed to correctly build the static libraries. Note that cross-compiling will require the use of
lld. Ensure that
lld-link.exe is available to clang via your path. Additionally, the ICU headers and libraries need to be provided for the build.
--extra-cmake-options=-DSWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER=FALSE,\ -DCMAKE_AR=<path to llvm-ar>,\ -DCMAKE_RANLIB=<path to llvm-ranlib>,\ -DSWIFT_SDKS='OSX;WINDOWS',\ -DSWIFT_WINDOWS_x86_64_ICU_I18N_INCLUDE=<path to ICU i18n includes>,\ -DSWIFT_WINDOWS_x86_64_ICU_UC_INCLUDE=<path to ICU UC includes>,\ -DSWIFT_WINDOWS_x86_64_ICU_I18N=<path to ICU i18n lib>,\ -DSWIFT_WINDOWS_x86_64_ICU_UC=<path to ICU UC lib>
For Linux, you will need to build the Linux SDK instead of the macOS SDK by replacing the cmake option with
From the build directory, you can build the Swift runtime and standard library for Windows using