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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/async-await/async-fn-size-moved-locals.rs | |
parent | Initial commit. (diff) | |
download | rustc-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.rs | 118 |
1 files changed, 118 insertions, 0 deletions
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 new file mode 100644 index 000000000..155662566 --- /dev/null +++ b/src/test/ui/async-await/async-fn-size-moved-locals.rs @@ -0,0 +1,118 @@ +// 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())); +} |