67870d1518
This implements the s390x back-end portion of the solution for https://github.com/bytecodealliance/wasmtime/issues/4566 We now support both big- and little-endian vector lane order in code generation. The order used for a function is determined by the function's ABI: if it uses a Wasmtime ABI, it will use little-endian lane order, and big-endian lane order otherwise. (This ensures that all raw_bitcast instructions generated by both wasmtime and other cranelift frontends can always be implemented as a no-op.) Lane order affects the implementation of a number of operations: - Vector immediates - Vector memory load / store (in big- and little-endian variants) - Operations explicitly using lane numbers (insertlane, extractlane, shuffle, swizzle) - Operations implicitly using lane numbers (iadd_pairwise, narrow/widen, promote/demote, fcvt_low, vhigh_bits) In addition, when calling a function using a different lane order, we need to lane-swap all vector values passed or returned in registers. A small number of changes to common code were also needed: - Ensure we always select a Wasmtime calling convention on s390x in crates/cranelift (func_signature). - Fix vector immediates for filetests/runtests. In PR #4427, I attempted to fix this by byte-swapping the V128 value, but with the new scheme, we'd instead need to perform a per-lane byte swap. Since we do not know the actual type in write_to_slice and read_from_slice, this isn't easily possible. Revert this part of PR #4427 again, and instead just mark the memory buffer as little-endian when emitting the trampoline; the back-end will then emit correct code to load the constant. - Change a runtest in simd-bitselect-to-vselect.clif to no longer make little-endian lane order assumptions. - Remove runtests in simd-swizzle.clif that make little-endian lane order assumptions by relying on implicit type conversion when using a non-i16x8 swizzle result type (this feature should probably be removed anyway). Tested with both wasmtime and cg_clif.
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
-
Fast. Wasmtime is built on the optimizing Cranelift code generator to quickly generate high-quality machine code either at runtime or ahead-of-time. Wasmtime's runtime is also optimized for cases such as efficient instantiation, low-overhead transitions between the embedder and wasm, and scalability of concurrent instances.
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Secure. Wasmtime's development is strongly focused on the correctness of its implementation with 24/7 fuzzing donated by Google's OSS Fuzz, leveraging Rust's API and runtime safety guarantees, careful design of features and APIs through an RFC process, a security policy in place for when things go wrong, and a release policy for patching older versions as well. We follow best practices for defense-in-depth and known protections and mitigations for issues like Spectre. Finally, we're working to push the state-of-the-art by collaborating with academic researchers to formally verify critical parts of Wasmtime and Cranelift.
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Configurable. Wastime supports a rich set of APIs and build time configuration to provide many options such as further means of restricting WebAssembly beyond its basic guarantees such as its CPU and Memory consumption. Wasmtime also runs in tiny environments all the way up to massive servers with many concurrent instances.
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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, CMake orwasmtimeConan 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.