Files
wasmtime/examples/linking.rs
Dan Gohman 9364eb1d98 Refactor (#1524)
* Compute instance exports on demand.

Instead having instances eagerly compute a Vec of Externs, and bumping
the refcount for each Extern, compute Externs on demand.

This also enables `Instance::get_export` to avoid doing a linear search.

This also means that the closure returned by `get0` and friends now
holds an `InstanceHandle` to dynamically hold the instance live rather
than being scoped to a lifetime.

* Compute module imports and exports on demand too.

And compute Extern::ty on demand too.

* Add a utility function for computing an ExternType.

* Add a utility function for looking up a function's signature.

* Add a utility function for computing the ValType of a Global.

* Rename wasmtime_environ::Export to EntityIndex.

This helps differentiate it from other Export types in the tree, and
describes what it is.

* Fix a typo in a comment.

* Simplify module imports and exports.

* Make `Instance::exports` return the export names.

This significantly simplifies the public API, as it's relatively common
to need the names, and this avoids the need to do a zip with
`Module::exports`.

This also changes `ImportType` and `ExportType` to have public members
instead of private members and accessors, as I find that simplifies the
usage particularly in cases where there are temporary instances.

* Remove `Instance::module`.

This doesn't quite remove `Instance`'s `module` member, it gets a step
closer.

* Use a InstanceHandle utility function.

* Don't consume self in the `Func::get*` methods.

Instead, just create a closure containing the instance handle and the
export for them to call.

* Use `ExactSizeIterator` to avoid needing separate `num_*` methods.

* Rename `Extern::func()` etc. to `into_func()` etc.

* Revise examples to avoid using `nth`.

* Add convenience methods to instance for getting specific extern types.

* Use the convenience functions in more tests and examples.

* Avoid cloning strings for `ImportType` and `ExportType`.

* Remove more obviated clone() calls.

* Simplify `Func`'s closure state.

* Make wasmtime::Export's fields private.

This makes them more consistent with ExportType.

* Fix compilation error.

* Make a lifetime parameter explicit, and use better lifetime names.

Instead of 'me, use 'instance and 'module to make it clear what the
lifetime is.

* More lifetime cleanups.
2020-04-20 15:55:33 -05:00

34 lines
1.2 KiB
Rust

//! Example of instantiating two modules which link to each other.
// You can execute this example with `cargo run --example linking`
use anyhow::Result;
use wasmtime::*;
use wasmtime_wasi::{Wasi, WasiCtx};
fn main() -> Result<()> {
let store = Store::default();
// First set up our linker which is going to be linking modules together. We
// want our linker to have wasi available, so we set that up here as well.
let mut linker = Linker::new(&store);
let wasi = Wasi::new(&store, WasiCtx::new(std::env::args())?);
wasi.add_to_linker(&mut linker)?;
// Load and compile our two modules
let linking1 = Module::from_file(&store, "examples/linking1.wat")?;
let linking2 = Module::from_file(&store, "examples/linking2.wat")?;
// Instantiate our first module which only uses WASI, then register that
// instance with the linker since the next linking will use it.
let linking2 = linker.instantiate(&linking2)?;
linker.instance("linking2", &linking2)?;
// And with that we can perform the final link and the execute the module.
let linking1 = linker.instantiate(&linking1)?;
let run = linking1.get_func("run").unwrap();
let run = run.get0::<()>()?;
run()?;
Ok(())
}