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The main purpose for doing this is that this is a large piece of functionality used by Wasmtime which is entirely independent of Cranelift. Eventually Wasmtime wants to be able to compile without Cranelift, but it can't also depend on `cranelift-wasm` in that situation for module translation which means that something needs to happen. One option is to refactor what's in `cranelift-wasm` into a separate crate (since all these pieces don't actually depend on `cranelift-codegen`), but I personally chose to not do this because: * The `ModuleEnvironment` trait, AFAIK, only has a primary user of Wasmtime. The Spidermonkey integration, for example, does not use this. * This is an extra layer of abstraction between Wasmtime and the compilation phase which was a bit of a pain to maintain. It couldn't be Wasmtime-specific as it was part of Cranelift but at the same time it had lots of Wasmtime-centric functionality (such as module linking). * Updating the "dummy" implementation has become pretty onerous over time as frequent additions are made and the "dummy" implementation was never actually used anywhere. This ended up feeling like effectively busy-work to update this. For these reasons I've opted to to move the meat of `cranelift-wasm` used by `wasmtime-environ` directly into `wasmtime-environ`. This means that the only real meat that Wasmtime uses from `cranelift-wasm` is the function-translation bits in the `wasmtime-cranelift` crate. The changes in `wasmtime-environ` are largely to inline module parsing together so it's a bit easier to follow instead of trying to connect the dots between lots of various function calls.
wasmtime
A standalone runtime for WebAssembly
A Bytecode Alliance project
Guide | Contributing | Website | Chat
Installation
The Wasmtime CLI can be installed on Linux and macOS with a small install script:
$ curl https://wasmtime.dev/install.sh -sSf | bash
Windows or otherwise interested users can download installers and binaries directly from the GitHub Releases page.
Example
If you've got the Rust compiler installed then you can take some Rust source code:
fn main() {
println!("Hello, world!");
}
and compile/run it with:
$ rustup target add wasm32-wasi
$ rustc hello.rs --target wasm32-wasi
$ wasmtime hello.wasm
Hello, world!
Features
-
Lightweight. Wasmtime is a standalone runtime for WebAssembly that scales with your needs. It fits on tiny chips as well as makes use of huge servers. Wasmtime can be embedded into almost any application too.
-
Fast. Wasmtime is built on the optimizing Cranelift code generator to quickly generate high-quality machine code at runtime.
-
Configurable. Whether you need to precompile your wasm ahead of time, generate code blazingly fast with Lightbeam, or interpret it at runtime, Wasmtime has you covered for all your wasm-executing needs.
-
WASI. Wasmtime supports a rich set of APIs for interacting with the host environment through the WASI standard.
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Standards Compliant. Wasmtime passes the official WebAssembly test suite, implements the official C API of wasm, and implements future proposals to WebAssembly as well. Wasmtime developers are intimately engaged with the WebAssembly standards process all along the way too.
Language Support
You can use Wasmtime from a variety of different languages through embeddings of the implementation:
- Rust - the
wasmtimecrate - C - the
wasm.h,wasi.h, andwasmtime.hheaders - [C++] - the
wasmtime-cpprepository - Python - the
wasmtimePyPI package - .NET - the
WasmtimeNuGet package - Go - the
wasmtime-gorepository
Documentation
📚 Read the Wasmtime guide here! 📚
The wasmtime guide is the best starting point to learn about what Wasmtime can do for you or help answer your questions about Wasmtime. If you're curious in contributing to Wasmtime, it can also help you do that!
It's Wasmtime.