b0939f6626
* Remove explicit `S` type parameters This commit removes the explicit `S` type parameter on `Func::typed` and `Instance::get_typed_func`. Historical versions of Rust required that this be a type parameter but recent rustcs support a mixture of explicit type parameters and `impl Trait`. This removes, at callsites, a superfluous `, _` argument which otherwise never needs specification. * Fix mdbook examples
57 lines
1.9 KiB
Rust
57 lines
1.9 KiB
Rust
use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
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use wasmtime::*;
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#[test]
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fn host_always_has_some_stack() -> anyhow::Result<()> {
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static HITS: AtomicUsize = AtomicUsize::new(0);
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// assume hosts always have at least 128k of stack
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const HOST_STACK: usize = 128 * 1024;
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let mut store = Store::<()>::default();
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// Create a module that's infinitely recursive, but calls the host on each
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// level of wasm stack to always test how much host stack we have left.
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let module = Module::new(
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store.engine(),
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r#"
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(module
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(import "" "" (func $host))
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(func $recursive (export "foo")
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call $host
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call $recursive)
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)
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"#,
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)?;
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let func = Func::wrap(&mut store, test_host_stack);
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let instance = Instance::new(&mut store, &module, &[func.into()])?;
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let foo = instance.get_typed_func::<(), ()>(&mut store, "foo")?;
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// Make sure that our function traps and the trap says that the call stack
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// has been exhausted.
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let trap = foo.call(&mut store, ()).unwrap_err().downcast::<Trap>()?;
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assert_eq!(trap, Trap::StackOverflow);
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// Additionally, however, and this is the crucial test, make sure that the
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// host function actually completed. If HITS is 1 then we entered but didn't
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// exit meaning we segfaulted while executing the host, yet still tried to
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// recover from it with longjmp.
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assert_eq!(HITS.load(SeqCst), 0);
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return Ok(());
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fn test_host_stack() {
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HITS.fetch_add(1, SeqCst);
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assert!(consume_some_stack(0, HOST_STACK) > 0);
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HITS.fetch_sub(1, SeqCst);
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}
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#[inline(never)]
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fn consume_some_stack(ptr: usize, stack: usize) -> usize {
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if stack == 0 {
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return ptr;
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}
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let mut space = [0u8; 1024];
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consume_some_stack(space.as_mut_ptr() as usize, stack.saturating_sub(1024))
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}
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}
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