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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/async-await/async-fn-size-moved-locals.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/async-await/async-fn-size-moved-locals.rs')
-rw-r--r--src/test/ui/async-await/async-fn-size-moved-locals.rs118
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diff --git a/src/test/ui/async-await/async-fn-size-moved-locals.rs b/src/test/ui/async-await/async-fn-size-moved-locals.rs
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+// Test that we don't duplicate storage for futures moved around in .await, and
+// for futures moved into other futures.
+//
+// The exact sizes can change by a few bytes (we'd like to know when they do).
+// What we don't want to see is the wrong multiple of 1024 (the size of BigFut)
+// being reflected in the size.
+//
+// See issue #59123 for a full explanation.
+
+// ignore-emscripten (sizes don't match)
+// run-pass
+
+// edition:2018
+
+use std::future::Future;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+const BIG_FUT_SIZE: usize = 1024;
+struct BigFut(#[allow(unused_tuple_struct_fields)] [u8; BIG_FUT_SIZE]);
+
+impl BigFut {
+ fn new() -> Self {
+ BigFut([0; BIG_FUT_SIZE])
+ }
+}
+
+impl Drop for BigFut {
+ fn drop(&mut self) {}
+}
+
+impl Future for BigFut {
+ type Output = ();
+
+ fn poll(self: Pin<&mut Self>, _ctx: &mut Context<'_>) -> Poll<Self::Output> {
+ Poll::Ready(())
+ }
+}
+
+#[allow(dead_code)]
+struct Joiner {
+ a: Option<BigFut>,
+ b: Option<BigFut>,
+ c: Option<BigFut>,
+}
+
+impl Future for Joiner {
+ type Output = ();
+
+ fn poll(self: Pin<&mut Self>, _ctx: &mut Context<'_>) -> Poll<Self::Output> {
+ Poll::Ready(())
+ }
+}
+
+fn noop() {}
+
+async fn single() {
+ let x = BigFut::new();
+ x.await;
+}
+
+async fn single_with_noop() {
+ let x = BigFut::new();
+ noop();
+ x.await;
+}
+
+async fn joined() {
+ let a = BigFut::new();
+ let b = BigFut::new();
+ let c = BigFut::new();
+
+ let joiner = Joiner {
+ a: Some(a),
+ b: Some(b),
+ c: Some(c),
+ };
+ joiner.await
+}
+
+async fn joined_with_noop() {
+ let a = BigFut::new();
+ let b = BigFut::new();
+ let c = BigFut::new();
+
+ let joiner = Joiner {
+ a: Some(a),
+ b: Some(b),
+ c: Some(c),
+ };
+ noop();
+ joiner.await
+}
+
+async fn mixed_sizes() {
+ let a = BigFut::new();
+ let b = BigFut::new();
+ let c = BigFut::new();
+ let d = BigFut::new();
+ let e = BigFut::new();
+ let joiner = Joiner {
+ a: Some(a),
+ b: Some(b),
+ c: Some(c),
+ };
+
+ d.await;
+ e.await;
+ joiner.await;
+}
+
+fn main() {
+ assert_eq!(1025, std::mem::size_of_val(&single()));
+ assert_eq!(1026, std::mem::size_of_val(&single_with_noop()));
+ assert_eq!(3076, std::mem::size_of_val(&joined()));
+ assert_eq!(3076, std::mem::size_of_val(&joined_with_noop()));
+ assert_eq!(6157, std::mem::size_of_val(&mixed_sizes()));
+}