Building Testing and Debugging

Building, Testing, and Debugging

This page contains instructions for building Roslyn on Windows. For special instructions on building Roslyn on Linux see here.

Required Software

Visual Studio 2015 with the Visual Studio Extensibility and Windows 10 tools optional components installed
To prevent unnecessary project.json changes, turn off NuGet package restore within Visual Studio
- Uncheck Tools -> Options -> NuGet Package Manager -> General -> Automatically check for missing packages during build in Visual Studio

Getting the code

Open Developer Command Prompt for VS2015
Clone https://github.com/dotnet/roslyn
Run: nuget.exe restore Roslyn.sln
Open Roslyn.sln

Running Unit Tests

To run the unit tests:

msbuild /v:m /m BuildAndTest.proj /p:PublicBuild=true /p:DeployExtension=false

This command will build and run all of the code / tests which are supported on the current public build of Visual Studio 2015.

To debug suites use the xunit.console.x86.exe runner command which is included in the xunit.runners NuGet package. Make sure to use a 2.0 version of the runner.

xunit.console.x86.exe [UnitTestDll] -noshadow

Contributing

Please see Contributing Code for details on contributing changes back to the code.

Strong Name Verification

Roslyn binaries are configured to be delay signed using the Microsoft strong name key. We are using a new technique to allow these assemblies to be loaded - currently 'fakesign' - these assemblies do not need to have strong name signing disabled to be loaded. However, they cannot be installed in the GAC neither can they be loaded from a partially trusted AppDomain.

In order to test changes in Visual Studio without affecting the normal development environment, Visual Studio can be run using an isolated registry hive and AppData directories via the /rootSuffix Roslyn command line option. When Roslyn is built it creates and populates this hive with the necessary packages.

"%devenvdir%"\devenv.exe /rootSuffix Roslyn

Download NuGet Packages

From the command prompt, change directory to <clone dir> and run Src\.nuget\nuget restore Src\Roslyn.sln

This ensures that all of the references and tools needed to build Roslyn are present on the computer. Because we use toolset packages, it's important to do this before opening the solution.

Deploying changes to Visual Studio

When you build using VS 2015 the updates will be deployed to the Roslyn Hive and ready for debugging. Note that only the components up to the Workspaces layer will be deployed.

Debugging Visual Studio

To begin

In Solution Explorer, right click the project "OpenSourceDebug" and choose "Set as Startup Project"
Choose Debug\Start Debugging (F5)

At this point, you will be able to debug the code that you changed. Note that not all aspects of the compiler are executed inside the Visual Studio process, so you may not hit all breakpoints. Visual Studio will call many of the APIs in your built binaries to power its own features, but if you invoke a build inside your target Visual Studio, that will launch a new instance of csc.exe and vbc.exe. This technique does not execute vbcscompiler.exe. csc.exe and vbc.exe are a separate process and are not retained in memory after compilation is complete.

If you have installed and built Roslyn with a previous build of Visual Studio, you may get an InvalidCast out of VS MEF, this is because the VS MEFCache is out of date, I cured this by re-creating the roslyn hive by running this command at a Dos Prompt:

"%VSSDK140Install%\VisualStudioIntegration\Tools\Bin\CreateExpInstance.exe" /Create /VSInstance=14.0 /RootSuffix=Roslyn

To Build a project using OSS built compilers

At the command line type:

set RoslynHive=VisualStudio\14.0Roslyn
MSBuild someproj.vbproj

Removing the code To remove the code

Start Task Manager and end all "VBCSCompiler.exe" processes
Delete the directory containing your local git clone

Uninstalling the End User Preview (optional)

You are welcome to continue to use the End User Preview to provide feedback on the potential new language and IDE features it contains, but if you want to uninstall it, you can do so by following these steps: