d4fcd32cdc
* Optimize generated code via the CLI by default This commit updates the behavior of the CLI and adds a new flag. It first enables the `--optimize` flag by default, ensuring that usage of the `wasmtime` CLI will enable cranelift optimizations by default. Next it also adds a `--opt-level` flag which is similar to Rust's `-Copt-level` where it takes a string argument of how to optimize. This is updates to support 0/1/2/s, where 1 is currently the same as 2 but added for consistency with other compilers. The default setting is `--opt-level=2`. When the `-O` flag is not passed the `--opt-level` flag is used, otherwise `-O` takes precedent in the sense that it implies `--opt-level=2` which is the highest optimization level. The thinking is that these flags will in general select the highest optimization level specified as the final optimization level. * Add inline docs * fix a test
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.