TinyWasm

A tiny WebAssembly Runtime written in Rust

Why TinyWasm?

• Tiny: TinyWasm is designed to be as small as possible without significantly compromising performance or functionality (< 6000 lines of code).
• Portable: TinyWasm runs on any platform that Rust can target, including other WebAssembly Runtimes, with minimal external dependencies.
• Lightweight: TinyWasm is easy to integrate and has a low call overhead, making it suitable for scripting and embedding.

Status

As of version 0.3.0, TinyWasm successfully passes all the WebAssembly 1.0 tests in the WebAssembly Test Suite. Work on the 2.0 tests is ongoing. This enables TinyWasm to run most WebAssembly programs, including executing TinyWasm itself compiled to WebAssembly (see examples/wasm-rust.rs). The results of the testsuites are available here.

The API is still unstable and may change at any time, so you probably don't want to use it in production yet. TinyWasm isn't primarily designed for high performance; it focuses more on simplicity, size, and portability. More details on its performance can be found in BENCHMARKS.md.

Future Development: The first major version will focus on improving the API and adding support for WASI. While doing so, I also want to further simplify and reduce the codebase's size and improve the parser's performance.

Supported Proposals

Usage

TinyWasm can be used through the tinywasm-cli CLI tool or as a library in your Rust project. Documentation can be found here.

Library

$ cargo add tinywasm

CLI

The CLI is mainly available for testing purposes, but can also be used to run WebAssembly programs.

$ cargo install tinywasm-cli
$ tinywasm-cli --help

Feature Flags

• std
  Enables the use of std and std::io for parsing from files and streams. This is enabled by default.
• logging
  Enables logging using the log crate. This is enabled by default.
• parser
  Enables the tinywasm-parser crate. This is enabled by default.
• archive
  Enables pre-parsing of archives. This is enabled by default.
• unsafe
  Uses unsafe code to improve performance, particularly in Memory access.

With all these features disabled, TinyWasm only depends on core, alloc ,and libm and can be used in no_std environments. Since libm is not as performant as the compiler's math intrinsics, it is recommended to use the std feature if possible (at least for now), especially on wasm32 targets.

Inspiration

Big thanks to the authors of the following projects, which have inspired and influenced TinyWasm:

• wasmi - an efficient and lightweight WebAssembly interpreter that also runs on no_std environments
• wasm3 - a high performance WebAssembly interpreter written in C
• wazero - a zero-dependency WebAssembly interpreter written in go
• wain - a zero-dependency WebAssembly interpreter written in Rust

I encourage you to check these projects out if you're looking for a more mature and feature-complete WebAssembly interpreter.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in TinyWasm by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Note: The GitHub repository contains a Submodule (crates/tinywasm-parser/data) which is licensed only under the Apache License, Version 2.0. This data is generated from the WebAssembly Specification and is only used for testing purposes and not included in the final binary.