wasmruntimelayer

wasm_runtime_layer creates a thin abstraction over WebAssembly runtimes, allowing for backend-agnostic host code. The interface is based upon the wasmtime and wasmi crates, but may be implemented for any runtime.

Usage

To use this crate, first instantiate a backend runtime. The runtime may be any value that implements backend::WasmEngine. Some runtimes are already implemented as optional features. Then, one can create an Engine from the backend runtime, and use it to initialize modules and instances:

```rust // 1. Instantiate a runtime let engine = Engine::new(wasmi::Engine::default()); let mut store = Store::new(&engine, ());

// 2. Create modules and instances, similar to other runtimes let modulebin = wabt::wat2wasm( r#" (module (type $t0 (func (param i32) (result i32))) (func $addone (export "addone") (type $t0) (param $p0 i32) (result i32) getlocal $p0 i32.const 1 i32.add)) "#, ) .unwrap();

let module = Module::new(&engine, std::io::Cursor::new(&module_bin)).unwrap(); let instance = Instance::new(&mut store, &module, &Imports::default()).unwrap();

let addone = instance .getexport(&store, "addone") .unwrap() .intofunc() .unwrap();

let mut result = [Value::I32(0)]; add_one .call(&mut store, &[Value::I32(42)], &mut result) .unwrap();

assert_eq!(result[0], Value::I32(43)); ```

Optional features and backends

backend_wasmi - Implements the WasmEngine trait for wasmi::Engine instances.

Contributions for additional backend implementations are welcome!