From ac623ff4034caeee28f423ae7800e8516cbc0078 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20Sanz=20Gonz=C3=A1lez?=
 <80487270+hsanzg@users.noreply.github.com>
Date: Wed, 19 Aug 2026 19:40:05 +0200
Subject: [PATCH] Double-word align `_Unwind_Exception`

---
 library/unwind/src/types.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/library/unwind/src/types.rs b/library/unwind/src/types.rs
index 7634052c93f33..d745b836e822b 100644
--- a/library/unwind/src/types.rs
+++ b/library/unwind/src/types.rs
@@ -42,6 +42,12 @@ pub const unwinder_private_data_size: usize = cfg_select! {
 };
 
 #[repr(C)]
+// The Itanium C++ ABI requires this type to have "double-word" alignment,
+// which libunwind and libgcc interpret as the maximum alignment of any
+// scalar type on the current target.
+#[cfg_attr(target_pointer_width = "16", repr(align(4)))]
+#[cfg_attr(target_pointer_width = "32", repr(align(8)))]
+#[cfg_attr(target_pointer_width = "64", repr(align(16)))]
 pub struct _Unwind_Exception {
     pub exception_class: _Unwind_Exception_Class,
     pub exception_cleanup: _Unwind_Exception_Cleanup_Fn,