b9dd48e34b
This adds support for StructArgument on s390x. The ABI for this platform requires that the address of the buffer holding the copy of the struct argument is passed from caller to callee as hidden pointer, using a register or overflow stack slot. To implement this, I've added an optional "pointer" filed to ABIArg::StructArg, and code to handle the pointer both in common abi_impl code and the s390x back-end. One notable change necessary to make this work involved the "copy_to_arg_order" mechanism. Currently, for struct args we only need to copy the data (and that need to happen before setting up any other args), while for non-struct args we only need to set up the appropriate registers or stack slots. This order is ensured by sorting the arguments appropriately into a "copy_to_arg_order" list. However, for struct args with explicit pointers we need to *both* copy the data (again, before everything else), *and* set up a register or stack slot. Since we now need to touch the argument twice, we cannot solve the ordering problem by a simple sort. Instead, the abi_impl common code now provided *two* callbacks, emit_copy_regs_to_buffer and emit_copy_regs_to_arg, and expects the back end to first call copy..to_buffer for all args, and then call copy.._to_arg for all args. This required updates to all back ends. In the s390x back end, in addition to the new ABI code, I'm now adding code to actually copy the struct data, using the MVC instruction (for small buffers) or a memcpy libcall (for larger buffers). This also requires a bit of new infrastructure: - MVC is the first memory-to-memory instruction we use, which needed a bit of memory argument tweaking - We also need to set up the infrastructure to emit libcalls. (This implements the first half of issue #4565.)
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.
-
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.