Dart Dynamic Import Library

This is an attempt / POC to build the Dart VM into a dynamic library, importable in any platform Dart supports.

Eventual support

The hope is that the the dynamic library will eventually support the following targets:

• A "Fully Featured" .dll / .so that supports booting Dart in different configurations:
  • Boot (or not) the service and kernel isolates
  • Support Dart Source Compilation and / or Kernel Isolates
  • JIT from source or .dil
• An AOT Only .dll / .so

Additionally we may have a static target that uses the same interface as the dynamic library, so the VM can be embedded on platforms that don't support dynamic linking.

I also hope to support all platforms that Dart currently supports, plus a few extra.

Using

Lastest builds of the libraries are now available for certain targets as artifacts from Github Actions as well as all the headers necessary.

Github Actions currently builds a Windows x64 .dll, A Linux x64 .so, and a macOS x64 .dylib. You can build a M-series dylib for macOS, but Github Actions does not currently support it.

Building

Prerequisets

You need:

• git
• Dart 3+
• C++ build tools for your platform (Visual Studio, XCode, gcc, etc)
• For Windows
  • 2019 16.61 with 10.0.20348.0 SDK don't forget install Debugger Tools
  • 2022 17 with ? SDK don't forget install Debugger Tools
  • 2017 15 with ? SDK don't forget install Debugger Tools
  • see dart-sdk\sdk\build\vs_toolchain.py
• CMake

Optionally, I recommend installing depot_tools and making sure it is on your path before running setup scripts. Without depot_tools, the scripts will download them anyway, but having them already set up will save you some time with subsequent builds.

Patching and Building Dart

NOTE: If you are building on Windows, I recommend running .\setup_env.ps1 before executing any other scripts.
This will set up some environment variables that will be needed to build Dart properly.

The first step is to build a statically linkable verison of Dart. This requires that we download Dart, patch some of the Dart build files, and then run the actual build. Thankfully there is a Dart script to do this. build_dart commandline

• -v -> Verbose Log
• -t -> Build Type all, release, debug

cd ./scripts/build_helpers
dart pub get
cd ../..
dart ./scripts/build_helpers/bin/build_dart.dart

This script does the following:

• Pulls down depot_tools if needed.
• Clones a fresh copy of the Dart sdk git repo using fetch if needed.
• Uses gsync to syncs the repo the the version of dart specificed in .dart_version.
• Applies dart_sdk.patch to the repo to create the statically linkable libdart library
• Builds libdart

CMake

Once Dart is built, you can use CMake to generate build files and / or build the libraries and examples

cmake -B ./.build .
cmake --build .\.build\ --config release

Troubleshooting

Unresolved externals building Dart on Linux

Two possible causes of this are having the snap package for Flutter installed, or having depot_tools not too far down your path.

First, uninstall the Flutter snap package and remove the dart-sdk build directory at dart-sdk/sdk/out and attempt to rebuild Dart.

If that doesn't work, put depot_tools at the front of your path, instead of at the end. Clean the dart-sdk build directory, then attempt a rebuild.