15c68f2cc1
* Moves CodeMemory, VMInterrupts and SignatureRegistry from Compiler * CompiledModule holds CodeMemory and GdbJitImageRegistration * Store keeps track of its JIT code * Makes "jit_int.rs" stuff Send+Sync * Adds the threads example.
59 lines
1.4 KiB
Markdown
59 lines
1.4 KiB
Markdown
# WebAssembly Text Format (`*.wat`)
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While not necessarily a full-blown language you might be curious how Wasmtime
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interacts with [the `*.wat` text format][spec]! The `wasmtime` CLI and Rust
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embedding API both support the `*.wat` text format by default.
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"Hello, World!" is pretty nontrivial in the `*.wat` format since it's
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assembly-like and not really intended to be a primary programming language. That
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being said we can create a simple add function to call it!
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For example if you have a file `add.wat` like so:
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```wat
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(module
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(func (export "add") (param i32 i32) (result i32)
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local.get 0
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local.get 1
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i32.add))
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```
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Then you can execute this on the CLI with:
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```sh
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$ wasmtime add.wat --invoke add 1 2
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warning: ...
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warning: ...
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3
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```
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And we can see that we're already adding numbers!
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You can also see how this works in the Rust API like so:
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```rust
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# extern crate wasmtime;
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# extern crate anyhow;
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use wasmtime::*;
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# fn main() -> anyhow::Result<()> {
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let engine = Engine::default();
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let store = Store::new(&engine);
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let wat = r#"
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(module
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(func (export "add") (param i32 i32) (result i32)
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local.get 0
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local.get 1
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i32.add))
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"#;
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let module = Module::new(&engine, wat)?;
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let instance = Instance::new(&store, &module, &[])?;
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let add = instance.get_func("add").unwrap();
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let add = add.get2::<i32, i32, i32>()?;
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println!("1 + 2 = {}", add(1, 2)?);
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# Ok(())
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# }
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```
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[spec]: https://webassembly.github.io/spec/core/text/index.html
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