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* Remove unnecessary into_iter/map Forgotten from a previous refactoring, this variable was already of the right type! * Move `wasmtime_jit::Compiler` into `wasmtime` This `Compiler` struct is mostly a historical artifact at this point and wasn't necessarily pulling much weight any more. This organization also doesn't lend itself super well to compiling out `cranelift` when the `Compiler` here is used for both parallel iteration configuration settings as well as compilation. The movement into `wasmtime` is relatively small, with `Module::build_artifacts` being the main function added here which is a merging of the previous functions removed from the `wasmtime-jit` crate. * Add a `cranelift` compile-time feature to `wasmtime` This commit concludes the saga of refactoring Wasmtime and making Cranelift an optional dependency by adding a new Cargo feature to the `wasmtime` crate called `cranelift`, which is enabled by default. This feature is implemented by having a new cfg for `wasmtime` itself, `cfg(compiler)`, which is used wherever compilation is necessary. This bubbles up to disable APIs such as `Module::new`, `Func::new`, `Engine::precompile_module`, and a number of `Config` methods affecting compiler configuration. Checks are added to CI that when built in this mode Wasmtime continues to successfully build. It's hoped that although this is effectively "sprinkle `#[cfg]` until things compile" this won't be too too bad to maintain over time since it's also an use case we're interested in supporting. With `cranelift` disabled the only way to create a `Module` is with the `Module::deserialize` method, which requires some form of precompiled artifact. Two consequences of this change are: * `Module::serialize` is also disabled in this mode. The reason for this is that serialized modules contain ISA/shared flags encoded in them which were used to produce the compiled code. There's no storage for this if compilation is disabled. This could probably be re-enabled in the future if necessary, but it may not end up being all that necessary. * Deserialized modules are not checked to ensure that their ISA/shared flags are compatible with the host CPU. This is actually already the case, though, with normal modules. We'll likely want to fix this in the future using a shared implementation for both these locations. Documentation should be updated to indicate that `cranelift` can be disabled, although it's not really the most prominent documentation because this is expected to be a somewhat niche use case (albeit important, just not too common). * Always enable cranelift for the C API * Fix doc example builds * Fix check tests on GitHub Actions
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.