Cross compilation with MSVC on Linux

This is a set of tools for using MSVC on Linux (and other Unix OSes).

It consists of two main parts:

• A Python script that downloads and unpacks MSVC and the Windows SDK

• Wrapping and tweaking of the unpacked MSVC/WinSDK to make MSVC work transparently from Unix based build tools with Wine

The first part also works without the second, as a source of MSVC and WinSDK for use with e.g. clang-cl.

This downloads and unpacks the necessary Visual Studio components using the same installer manifests as Visual Studio 2017/2019's installer uses. Downloading and installing it requires accepting the license, available at https://go.microsoft.com/fwlink/?LinkId=2086102 for the currently latest version.

As Visual Studio isn't redistributable, the installed toolchain isn't either.

To install, just run the following two commands:

./vsdownload.py --dest <dir>
./install.sh <dir>

The unpacking requires recent versions of msitools (0.98) and libgcab (1.2); sufficiently new versions are available in e.g. Ubuntu 19.04.

After installing the toolchain this way, there are 4 directories with tools, in <dest>/bin/<arch>, for all architectures out of x86, x64, arm and arm64, that should be added to the PATH before building with it.

There's also a reproducible dockerfile, that creates a docker image with the MSVC tools available in /opt/msvc. (This also serves as a testable example of an environment where the install is known to work.)

Build instructions for local installation

The following instructions are for setting up MSVC without docker.

Prerequisites

apt-get update
apt-get install -y wine64-development python3 msitools python3-simplejson python3-six ca-certificates winbind

Installation

We're going to install it into ~/my_msvc to avoid needing root privileges on a non-contained system.

# Download and unpack MSVC
./vsdownload.py --dest ~/my_msvc/opt/msvc
# Add wrapper scripts, do minor cleanup of the unpacked MSVC installation
./install.sh ~/my_msvc/opt/msvc

# Optional: Start a persistent wineserver
wineserver -k # Kill a potential old server
wineserver -p # Start a new server
wine64 wineboot # Run a process to start up all background wine processes

Setting up your project with CMake

You need to add the our MSVC installation to the path. After that we just run CMake command with a few extra settings:

export PATH=~/my_msvc/opt/msvc/bin/x64:$PATH
CC=cl CXX=cl cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_SYSTEM_NAME=Windows
make

Use with Clang/LLD in MSVC mode

It's possible to cross compile from Linux using Clang and LLD operating entirely in MSVC mode, without running any tools through Wine. This still requires the nonredistributable MSVC and WinSDK headers and libraries - which can be fetched and unpacked conveniently with msvc-wine.

To use clang/lld with MSVC/WinSDK headers provided by msvc-wine, first download and set up the MSVC installation as usual. You need less prerequisites as wine won't be needed:

apt-get update
apt-get install -y python3 msitools python3-simplejson python3-six ca-certificates

# Download and unpack MSVC
./vsdownload.py --dest ~/my_msvc
# Clean up headers, add scripts for setting up the environments
./install.sh ~/my_msvc

To let Clang/LLD find the headers and libraries, source the msvcenv-native.sh script to set up the INCLUDE and LIB environment variables, with the BIN variable pointing at the relevant bin directory set up by install.sh above.

BIN=~/my_msvc/bin/x64 . ./msvcenv-native.sh

After this, you can invoke clang-cl, clang --target=<arch>-windows-msvc or lld-link without needing to point it specifically towards the MSVC installation, e.g. like this:

clang-cl -c hello.c
lld-link hello.obj -out:hello.exe

clang --target=x86_64-windows-msvc hello.c -fuse-ld=lld -o hello.exe

This should work with most distributions of Clang (both upstream release packages and Linux distribution provided packages). Note that not all distributions provide the clang-cl frontend (or it may exist as a version-suffixed tool like clang-cl-14). If clang-cl or lld-link are unavailable but plain clang and lld (or ld.lld) binaries are available, it's enough to just create new symlinks named clang-cl and lld-link pointing at the existing binaries. (The binaries normally contain all support for all targets, but switch mode/behaviour based on what name they are invoked as.)

Do note that older versions of Clang/LLD might not work out of the box with the libraries from the very latest MSVC/WinSDK. Currently, at least Clang/LLD 13 seems to be required for MSVC 2019 16.8 or newer.

FAQ

Does it run on Ubuntu 18.04 LTS?

Yes, but the install scripts won't work because msitools is too old. You'll need to install either via Docker or on a real Ubuntu 20.04 LTS machine; and later copy paste the files under /opt/msvc.

Does it work with CMake?

Yes, but you need CMake 3.23, and either need winbind installed, or need to configure the build to always use embedded debug info (or a custom build of CMake that doesn't try to use separate PDB file debug info by default).

Even if configuring CMake with -DCMAKE_BUILD_TYPE=Release, CMake does call the compiler in Debug mode when it does the first few test invocations of the compiler. By default, CMake uses separate PDB file debug info, when compiling in Debug mode, i.e. using the /Zi compiler option (as opposed to the /Z7 option, storing the debug info in the individual object files).

When MSVC is invoked with the /Zi and /FS options, it spawns a background mspdbsrv.exe process and communicates with it. This requires the winbind package to be installed for this communication to work.

With CMake 3.25, it's possible to override the type of debug info even for the first few probing steps. This requires the CMake project to either set cmake_minimum_required(VERSION 3.25.0), or set cmake_policy(SET CMP0141 NEW), and requires the user to configure it with -DCMAKE_MSVC_DEBUG_INFORMATION_FORMAT=Embedded; in such a configuration, winbind isn't needed.

Can it build Debug versions?

Yes, but there may be troubles. From wine errors appearing in the logs/console to problems when trying to launch it because of missing debug redistributables. You will also have to install winbind (see next item).

For the best out-of-the-box experience build in Release mode.

fatal error C1902: Program database manager mismatch; please check your installation

You need winbind: sudo apt install winbind

Issue is being tracked.

What generators work with CMake?

The following generators were tested and known to work:

• Ninja
• Unix Makefiles

Other generators are untested and may or may not work. Use it at your own peril.

Do I need CMake to use msvc-wine?

No. Using Ninja or GNU Make directly should work.

I get ninja: error: build.ninja:225: bad $-escape (literal $ must be written as $$)

Visual Studio can switch between Debug/Release/RelWithDebInfo/etc at build time in the IDE.

It's slightly common for CMake projects to use $(CONFIGURATION) macro from Visual Studio to resolve commands to each intended configuration automatically.

However generators like Ninja/Unix Makefiles can only target one configuration at a time.

You'll have to edit the CMake script to use ${CMAKE_BUILD_TYPE} instead when using Ninja/Unix Makefiles generators (which is extremely rare to use in an actual Windows environment).

Note the script may have other hardcoded commands which use $(...) syntax that make no sense when using generators other than Visual Studio; and will need to be fixed accordingly.

This is not an msvc-wine bug.