a66724aafd
This PR changes the aarch64 ABI implementation to use positive offsets from SP, rather than negative offsets from FP, to refer to spill slots and stack-local storage. This allows for better addressing-mode options, and hence slightly better code: e.g., the unsigned scaled 12-bit offset mode can be used to reach anywhere in a 32KB frame without extra address-construction instructions, whereas negative offsets are limited to a signed 9-bit unscaled mode (-256 bytes). To enable this, the PR introduces a notion of "nominal SP offsets" as a virtual addressing mode, lowered during the emission pass. The offsets are relative to "SP after adjusting downward to allocate stack/spill slots", but before pushing clobbers. This allows the addressing-mode expressions to be generated before register allocation (or during it, for spill/reload sequences). To convert these offsets into *true* offsets from SP, we need to track how much further SP is moved downward, and compensate for this. We do so with "virtual SP offset adjustment" pseudo-instructions: these are seen by the emission pass, and result in no instruction (0 byte output), but update state that is now threaded through each instruction emission in turn. In this way, we can push e.g. stack args for a call and adjust the virtual SP offset, allowing reloads from nominal-SP-relative spillslots while we do the argument setup with "real SP offsets" at the same time.
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.
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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 - Python - the
wasmtimePyPI package - .NET - the
WasmtimeNuGet package - Go - the wasmtime-go repository
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.