Reactor support. (#1565)

* Reactor support.

This implements the new WASI ABI described here:

https://github.com/WebAssembly/WASI/blob/master/design/application-abi.md

It adds APIs to `Instance` and `Linker` with support for running
WASI programs, and also simplifies the process of instantiating
WASI API modules.

This currently only includes Rust API support.

* Add comments and fix a typo in a comment.

* Fix a rustdoc warning.

* Tidy an unneeded `mut`.

* Factor out instance initialization with `NewInstance`.

This also separates instantiation from initialization in a manner
similar to https://github.com/bytecodealliance/lucet/pull/506.

* Update fuzzing oracles for the API changes.

* Remove `wasi_linker` and clarify that Commands/Reactors aren't connected to WASI.

* Move Command/Reactor semantics into the Linker.

* C API support.

* Fix fuzzer build.

* Update usage syntax from "::" to "=".

* Remove `NewInstance` and `start()`.

* Elaborate on Commands and Reactors and add a spec link.

* Add more comments.

* Fix wat syntax.

* Fix wat.

* Use the `Debug` formatter to format an anyhow::Error.

* Fix wat.
This commit is contained in:
Dan Gohman
2020-05-26 08:39:40 -07:00
committed by GitHub
parent c619136752
commit 3715e19c67
19 changed files with 724 additions and 245 deletions

View File

@@ -9,32 +9,18 @@ use wasmtime_wasi::{Wasi, WasiCtx};
fn main() -> Result<()> {
let store = Store::default();
let module = Module::from_file(&store, "target/wasm32-wasi/debug/wasi.wasm")?;
let mut linker = Linker::new(&store);
// Create an instance of `Wasi` which contains a `WasiCtx`. Note that
// `WasiCtx` provides a number of ways to configure what the target program
// will have access to.
let wasi = Wasi::new(&store, WasiCtx::new(std::env::args())?);
let mut imports = Vec::new();
for import in module.imports() {
if import.module() == "wasi_snapshot_preview1" {
if let Some(export) = wasi.get_export(import.name()) {
imports.push(Extern::from(export.clone()));
continue;
}
}
panic!(
"couldn't find import for `{}::{}`",
import.module(),
import.name()
);
}
wasi.add_to_linker(&mut linker)?;
// Instantiate our module with the imports we've created, and run it.
let module = Module::from_file(&store, "target/wasm32-wasi/debug/wasi.wasm")?;
linker.module("", &module)?;
linker.get_default("")?.get0::<()>()?()?;
// Instance our module with the imports we've created, then we can run the
// standard wasi `_start` function.
let instance = Instance::new(&module, &imports)?;
let start = instance.get_func("_start").unwrap();
let start = start.get0::<()>()?;
start()?;
Ok(())
}