From c2bbfeadcce08a4b8ce02b66906ecc542cc9df39 Mon Sep 17 00:00:00 2001
From: Paul Dicker <pitdicker@gmail.com>
Date: Thu, 24 Oct 2019 17:08:23 +0200
Subject: Always align Waiter to 4 bytes

---
 src/libstd/sync/once.rs | 1 +
 1 file changed, 1 insertion(+)

(limited to 'src/libstd/sync')

diff --git a/src/libstd/sync/once.rs b/src/libstd/sync/once.rs
index 4c14fe75643..c135471e2f2 100644
--- a/src/libstd/sync/once.rs
+++ b/src/libstd/sync/once.rs
@@ -171,6 +171,7 @@ const STATE_MASK: usize = 0x3;
 // `wait` would both hand out a mutable reference to its `Waiter` node, and keep
 // a shared reference to check `signaled`. Instead we hold shared references and
 // use interior mutability.
+#[repr(align(4))] // Ensure the two lower bits are free to use as state bits.
 struct Waiter {
     thread: Cell<Option<Thread>>,
     signaled: AtomicBool,
-- 
cgit 1.4.1-3-g733a5