Skip to content

Latest commit

 

History

History
67 lines (51 loc) · 2.42 KB

README.md

File metadata and controls

67 lines (51 loc) · 2.42 KB
Raw

Wasm.SourceGen

C# Source generator for developing WASI modules and components

About

Note: this project is experimental and should not be used in any serious context

This repository contains a C# source generator for generating WASI modules from pure C# code. It does this by generating C code calling into the mono C driver. This can can then be compiled to a WASI module using the dotnet-wasi-sdk. In the future, this will hopefully support the Component Model.

The package has 2 projects:

  • Wasm.SourceGen is a class library holding types and functions relating to the source generator, this namespace can be used by guest modules and C# hosts.
  • Wasm.SourceGen.Analyzers contains the actual C# source generator.

Usage

Parameter & Return types

Not all types are currently supported, or will be supported. My goal is to get to the following supported at least:

  • built-in types (strings, int, float, etc)
  • Arrays
  • Arbitrary classes and structs

For now only string works as function parameter, with int or void as return :)

Exporting a function

A function can be exposed by applying the WasmExportAttribute from Wasm.SourceGen to a static method:

[WasmExport("hello")]
public static void Hello(string name)
{
  Console.WriteLine($"Hello {name}, from WASI");
}

The above will export the Hello function and expose it as hello in the WASM module. It can be called with wasmtime like so:

//...
var hello = instance.GetFunction<int, int>("hello");
var name = WasmtimeUtils.CreateWasmString(instance, "MyName");
hello.Invoke(name);

Importing a function

A function can be imported from a WASM host by applying the Wasm.SourceGen.WasmImportAttribute to a public static extern method marked with [MethodImpl(MethodImplOptions.InternalCall)]:

[MethodImpl(MethodImplOptions.InternalCall)]
[WasmImport("env", "hello")]
public static extern void Hello();

Executing

The project can be built and run by executing:

make run

Contributing

If you are interested in contributing, please open an issue to discuss the desired change. Proactive PR's are also very much welcome!