cc4be18119
This commit uses the `*.witx` files describing the current wasi API to reduce the boilerplate used to define implementations in the `wasmtime-wasi` crate. Eventually I'd like to remove lots of boilerplate in the `wasi-common` crate too, but this should at least be a good start! The boilerplate removed here is: * No need to list each function to add it to the `wasmtime_runtime::Module` being created * No need to list the signature of the function in a separate `syscalls.rs` file. Instead the `*.witx` file is processed in a single-use macro inside the `wasmtime-wasi` crate. This macro uses the signatures known from `*.witx` to automatically register with the right type in the wasm module as well as define a wrapper that the wasm module will call into. Functionally this is all the same as before, it's just defined in a different way now! The shim generated by this macro which wasmtime calls into only uses `i32`/`i64`/etc wasm types, and it internally uses `as` casts to convert to the right wasi types when delegating into the `wasi-common` crate. One change was necessary to get this implemented, however. The functions in `wasi-common` sometimes took `WasiCtx` and sometimes took a slice of memory. After this PR they uniformly all require both `WasiCtx` and memory so the wrappers can be auto-generated. The arguments are ignored if they weren't previously required.
Wasmtime: a WebAssembly Runtime
A Bytecode Alliance project
Wasmtime is a standalone wasm-only optimizing runtime for WebAssembly and WASI. It runs WebAssembly code outside of the Web, and can be used both as a command-line utility or as a library embedded in a larger application.
To get started, visit wasmtime.dev.
There are Rust, C, and C++ toolchains that can compile programs with WASI. See the WASI intro for more information, and the WASI tutorial for a tutorial on compiling and running programs using WASI and wasmtime, as well as an overview of the filesystem sandboxing system.
Wasmtime passes the WebAssembly spec testsuite. To run it, update the
tests/spec_testsuite submodule with git submodule update --remote, and it
will be run as part of cargo test.
Wasmtime does not yet implement Spectre mitigations, however this is a subject of ongoing research.
Additional goals for Wasmtime include:
- Support a variety of host APIs (not just WASI), with fast calling sequences, and develop proposals for additional API modules to be part of WASI.
- Facilitate development and testing around the Cranelift and Lightbeam JITs, and other WebAssembly execution strategies.
- Develop a native ABI used for compiling WebAssembly suitable for use in both JIT and AOT to native object files.
Including Wasmtime in your project
Wasmtime exposes an API for embedding as a library through the wasmtime subcrate,
which contains both a high-level and safe Rust API, as well as a C-compatible API
compatible with the proposed WebAssembly C API.
For more information, see the Rust API embedding chapter of the Wasmtime documentation.
It's Wasmtime.