80 lines
3.8 KiB
Markdown
80 lines
3.8 KiB
Markdown
# Wasmtime: a WebAssembly Runtime.
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Wasmtime is a standalone wasm-only runtime for [WebAssembly], using the [Cranelift] JIT.
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It runs WebAssembly code [outside of the Web], and can be used both as a command-line
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utility or as a library embedded in a larger application.
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[WebAssembly]: https://webassembly.org/
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[Cranelift]: https://github.com/CraneStation/cranelift
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[outside of the Web]: https://webassembly.org/docs/non-web/
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[](https://travis-ci.org/CraneStation/wasmtime)
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[](https://ci.appveyor.com/project/CraneStation/cranelift)
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[](https://gitter.im/CraneStation/Lobby)
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Wasmtime passes the WebAssembly spec testsuite, and supports a new system
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API proposal called [WebAssembly System Interface], or WASI.
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Wasmtime includes a git submodule; in order to build it, it's necessary to
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obtain a full checkout, like this:
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```
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git clone --recurse-submodules https://github.com/CraneStation/wasmtime.git
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```
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To build Wasmtime, install cmake and clang, and then build with cargo, such
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as with "cargo build --release". For information on installing clang, see
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[rust-bindgen's documentation](https://github.com/rust-lang/rust-bindgen/blob/master/book/src/requirements.md).
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There are Rust, C, and C++ toolchains that can compile programs with WASI. See
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the [WASI intro][WASI intro] for more information, and the [WASI tutorial][WASI tutorial]
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for a tutorial on compiling and running programs using WASI and wasmtime, as
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well as an overview of the filesystem sandboxing system.
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Wasmtime does not yet implement Spectre mitigations, such as those being
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pioneered [by](https://www.wasmjit.org/blog/spectre-mitigations-part-1.html)
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[wasmjit](https://www.wasmjit.org/blog/spectre-mitigations-part-2.html),
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however this is a subject of ongoing research.
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[CloudABI]: https://cloudabi.org/
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[WebAssembly System Interface]: docs/WASI-overview.md
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[WASI intro]: docs/WASI-intro.md
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[WASI tutorial]: docs/WASI-tutorial.md
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Additional goals for Wasmtime include:
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- Support a variety of host APIs (not just WASI Core), with fast calling sequences,
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and develop proposals for additional API modules to be part of WASI.
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[Reference Sysroot](https://github.com/WebAssembly/reference-sysroot).
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- Implement the [proposed WebAssembly C API].
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- Facilitate testing, experimentation, and development around the [Cranelift] and
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[Lightbeam] JITs.
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- Develop a native ABI used for compiling WebAssembly suitable for use in both
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JIT and AOT to native object files.
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[proposed WebAssembly C API]: https://github.com/rossberg/wasm-c-api
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[Cranelift]: https://github.com/CraneStation/cranelift
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[Lightbeam]: https://github.com/CraneStation/lightbeam
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#### Including Wasmtime in your project
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Wasmtime exposes an API for JIT compilation through the `wasmtime-jit` subcrate, which depends on `wasmtime-environ` and `wasmtime-runtime` for the ABI and runtime support respectively. However, this API is not documented and subject to change. Please use at your own risk!
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Build the individual crates as such:
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```
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cargo build --package wasmtime-jit
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```
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Wasmtime does not currently publish these crates on crates.io. They may be included as a git dependency, like this:
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```toml
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[dependencies]
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wasmtime-environ = { git = "https://github.com/CraneStation/wasmtime", rev = "somecommithash" }
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wasmtime-runtime = { git = "https://github.com/CraneStation/wasmtime", rev = "somecommithash" }
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wasmtime-jit = { git = "https://github.com/CraneStation/wasmtime", rev = "somecommithash" }
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```
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All three crates must be specified as dependencies for `wasmtime-jit` to build correctly, at the moment.
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It's Wasmtime.
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