eb1991c579
This reverts commit 7b33f1c619.
Pushed a few extra commits by accident, so reverting this.
63 lines
1.4 KiB
Rust
63 lines
1.4 KiB
Rust
//! Example of instantiating of the WebAssembly module and
|
|
//! invoking its exported function.
|
|
|
|
use wasmtime::*;
|
|
|
|
const WAT: &str = r#"
|
|
(module
|
|
(func $gcd (param i32 i32) (result i32)
|
|
(local i32)
|
|
block ;; label = @1
|
|
block ;; label = @2
|
|
local.get 0
|
|
br_if 0 (;@2;)
|
|
local.get 1
|
|
local.set 2
|
|
br 1 (;@1;)
|
|
end
|
|
loop ;; label = @2
|
|
local.get 1
|
|
local.get 0
|
|
local.tee 2
|
|
i32.rem_u
|
|
local.set 0
|
|
local.get 2
|
|
local.set 1
|
|
local.get 0
|
|
br_if 0 (;@2;)
|
|
end
|
|
end
|
|
local.get 2
|
|
)
|
|
(export "gcd" (func $gcd))
|
|
)
|
|
"#;
|
|
|
|
fn main() -> anyhow::Result<()> {
|
|
// Load our WebAssembly (parsed WAT in our case), and then load it into a
|
|
// `Module` which is attached to a `Store` cache.
|
|
let wasm = wat::parse_str(WAT)?;
|
|
let store = Store::default();
|
|
let module = HostRef::new(Module::new(&store, &wasm)?);
|
|
|
|
// Find index of the `gcd` export.
|
|
let gcd_index = module
|
|
.borrow()
|
|
.exports()
|
|
.iter()
|
|
.enumerate()
|
|
.find(|(_, export)| export.name().to_string() == "gcd")
|
|
.unwrap()
|
|
.0;
|
|
|
|
// Instantiate the module.
|
|
let instance = Instance::new(&store, &module, &[])?;
|
|
|
|
// Invoke `gcd` export
|
|
let gcd = instance.exports()[gcd_index].func().expect("gcd");
|
|
let result = gcd.borrow().call(&[Val::from(6i32), Val::from(27i32)])?;
|
|
|
|
println!("{:?}", result);
|
|
Ok(())
|
|
}
|