BACIL 🦠

An experimental interpreter for .NET CIL binaries for GraalVM. While it only implements a small subset of the full ECMA-335 Common Language Infrastructure (CLI) standard, stuff it can run it runs within 10 times slower than .NET's official JIT runtime.

The project is written like an interpreter (you will find a familiar while(true) switch(opcode) in BytecodeNode.execute()), and leverages Truffle and the Graal compiler to turn it into a Just-In-Time (JIT) compiler.

Written as a part of a bachelor thesis called Truffle based .NET IL interpreter and compiler: run C# on Java Virtual Machine at Charles University, Prague. You can find the final thesis text here.

Building

For ease of building we use Maven, therefore building consists of running mvn package in the root of the project.

The resulting artifacts will be the language jar in language/target/language-1.0-SNAPSHOT.jar and a (shaded) launcher jar in launcher/target/bacil-launcher.jar.

Running

For running you'll need to obtain GraalVM and a copy of a .NET standard library. While the target for development was Java 8 and .NET Runtime 5.0.6 on both Linux and Windows, we succesfully ran the project on Java 11 with .NET 6.

You'll also need an assembly to run. If you don't have any handy, you can clone BACIL_examples.

Once you have all the prerequisites, you can run BACIL on Windows with .NET Runtime 5.0.6 like so:

BACIL>java -version
openjdk version "1.8.0_282"
OpenJDK Runtime Environment (build 1.8.0_282-b07)
OpenJDK 64-Bit Server VM GraalVM CE 21.0.0 (build 25.282-b07-jvmci-21.0-b06, mixed mode)

BACIL>java -Dtruffle.class.path.append=language/target/language-1.0-SNAPSHOT.jar -jar launcher/target/bacil-launcher.jar "--cil.libraryPath=c:\Program Files\dotnet\shared\Microsoft.NETCore.App\5.0.6" BACIL_examples\Inheritance\bin\Debug\net5.0\TestHarness.dll
Micka: Meow
Rex: Woof
Returned 4
Returned: 0
Runtime: 110ms

Apart from the last 2 lines (added by BACIL to aid debugging), the output should be identical when running the assemblies directly.

BACIL>dotnet BACIL_examples\Inheritance\bin\Debug\net5.0\TestHarness.dll
Micka: Meow
Rex: Woof
Returned 4

On Linux it's very similiar:

$ java -version
openjdk version "1.8.0_292"
OpenJDK Runtime Environment (build 1.8.0_292-b09)
OpenJDK 64-Bit Server VM GraalVM CE 21.1.0 (build 25.292-b09-jvmci-21.1-b05, mixed mode)

$ java -Dtruffle.class.path.append=language/target/language-1.0-SNAPSHOT.jar -jar launcher/target/bacil-launcher.jar --cil.libraryPath=../dotnet-runtime-5.0.6-linux-x64/shared/Microsoft.NETCore.App/5.0.6 BACIL_examples/Inheritance/bin/Debug/net5.0/TestHarness.dll
Micka: Meow
Rex: Woof
Returned 4
Returned: 0
Runtime: 348ms

$ dotnet BACIL_examples/Inheritance/bin/Debug/net5.0/TestHarness.dll
Micka: Meow
Rex: Woof
Returned 4

Always make sure you are running GraalVM and replace the libraryPath with path to the .NET standard library DLLs.