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103 lines
2.1 KiB
Rust
103 lines
2.1 KiB
Rust
// Test that we don't store uninitialized locals in futures from `async fn`.
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//
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// The exact sizes can change by a few bytes (we'd like to know when they do).
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// What we don't want to see is the wrong multiple of 1024 (the size of `Big`)
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// being reflected in the size.
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//@ ignore-emscripten (sizes don't match)
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//@ needs-unwind Size of Futures change on panic=abort
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//@ run-pass
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//@ edition:2018
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#![allow(unused_variables, unused_assignments)]
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use std::future::Future;
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use std::pin::Pin;
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use std::task::{Context, Poll};
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const BIG_FUT_SIZE: usize = 1024;
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struct Big(#[allow(dead_code)] [u8; BIG_FUT_SIZE]);
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impl Big {
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fn new() -> Self {
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Big([0; BIG_FUT_SIZE])
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}
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}
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impl Drop for Big {
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fn drop(&mut self) {}
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}
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#[allow(dead_code)]
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struct Joiner {
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a: Option<Big>,
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b: Option<Big>,
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c: Option<Big>,
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}
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impl Future for Joiner {
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type Output = ();
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fn poll(self: Pin<&mut Self>, _ctx: &mut Context<'_>) -> Poll<Self::Output> {
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Poll::Ready(())
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}
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}
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fn noop() {}
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async fn fut() {}
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async fn single() {
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let x;
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fut().await;
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x = Big::new();
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}
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async fn single_with_noop() {
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let x;
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fut().await;
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noop();
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x = Big::new();
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noop();
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}
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async fn joined() {
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let joiner;
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let a = Big::new();
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let b = Big::new();
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let c = Big::new();
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fut().await;
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joiner = Joiner { a: Some(a), b: Some(b), c: Some(c) };
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}
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async fn joined_with_noop() {
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let joiner;
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let a = Big::new();
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let b = Big::new();
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let c = Big::new();
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fut().await;
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noop();
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joiner = Joiner { a: Some(a), b: Some(b), c: Some(c) };
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noop();
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}
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async fn join_retval() -> Joiner {
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let a = Big::new();
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let b = Big::new();
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let c = Big::new();
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fut().await;
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noop();
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Joiner { a: Some(a), b: Some(b), c: Some(c) }
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}
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fn main() {
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assert_eq!(2, std::mem::size_of_val(&single()));
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assert_eq!(3, std::mem::size_of_val(&single_with_noop()));
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assert_eq!(3074, std::mem::size_of_val(&joined()));
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assert_eq!(3078, std::mem::size_of_val(&joined_with_noop()));
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assert_eq!(3074, std::mem::size_of_val(&join_retval()));
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}
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