d42c8692bc
As discussed in #3035, most backends have explicit `unimplemented!(...)` match-arms for opcode lowering cases that are not yet implemented; this allows the backend maintainer to easily see what is not yet implemented, and avoiding a catch-all wildcard arm is less error-prone as opcodes are added in the future. However, the x64 backend was the exception: as @akirilov-arm pointed out, it had a wildcard match arm. This fixes the issue by explicitly listing all opcodes the x64 backend does not yet implement. As per our tests, these opcodes are not used or need by Wasm lowering; but, it is good to know that they exist, so that we can eventually either support or remove them. This was a good exercise for me as I wasn't aware of a few of these in particular: e.g., aarch64 supports `bmask` while x64 does not, and there isn't a good reason why x64 shouldn't, especially if others hope to use Cranelift as a SIMD-capable general codegen in the future. The `unimplemented!()` cases are separate from `panic!()` ones: my convention here was to split out those that are logically just *missing* from those that should be *impossible*, mostly due to expected removal by legalization before we reach the lowering step.
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.
-
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.