ddd39cdb84
We currently skip some tests when running our qemu-based tests for aarch64 and s390x. Qemu has broken madvise(MADV_DONTNEED) semantics -- specifically, it just ignores madvise() [1]. We could continue to whack-a-mole the tests whenever we create new functionality that relies on madvise() semantics, but ideally we'd just have emulation that properly emulates! The earlier discussions on the qemu mailing list [2] had a proposed patch for this, but (i) this patch doesn't seem to apply cleanly anymore (it's 3.5 years old) and (ii) it's pretty complex due to the need to handle qemu's ability to emulate differing page sizes on host and guest. It turns out that we only really need this for CI when host and guest have the same page size (4KiB), so we *could* just pass the madvise()s through. I wouldn't expect such a patch to ever land upstream in qemu, but it satisfies our needs I think. So this PR modifies our CI setup to patch qemu before building it locally with a little one-off patch. [1] https://github.com/bytecodealliance/wasmtime/pull/2518#issuecomment-747280133 [2] https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg05416.html
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, 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 or usewasmtimeConan package - [C++] - the
wasmtime-cpprepository or usewasmtime-cppConan package - 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.