From a4e87e940620bc0e61caa7c42b1edc53c0aee7cb Mon Sep 17 00:00:00 2001
From: Jules Bertholet <julesbertholet@quoi.xyz>
Date: Wed, 10 Sep 2025 17:11:47 -0400
Subject: Support `#[rustc_align_static]` inside `thread_local!`

---
 src/tools/miri/tests/pass/static_align.rs | 60 +++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

(limited to 'src/tools')

diff --git a/src/tools/miri/tests/pass/static_align.rs b/src/tools/miri/tests/pass/static_align.rs
index f292f028568..bc6a9bf8af7 100644
--- a/src/tools/miri/tests/pass/static_align.rs
+++ b/src/tools/miri/tests/pass/static_align.rs
@@ -1,4 +1,7 @@
 #![feature(static_align)]
+#![deny(non_upper_case_globals)]
+
+use std::cell::Cell;
 
 // When a static uses `align(N)`, its address should be a multiple of `N`.
 
@@ -8,7 +11,64 @@ static FOO: u64 = 0;
 #[rustc_align_static(512)]
 static BAR: u64 = 0;
 
+struct HasDrop(*const HasDrop);
+
+impl Drop for HasDrop {
+    fn drop(&mut self) {
+        assert_eq!(core::ptr::from_mut(self).cast_const(), self.0);
+    }
+}
+
+thread_local! {
+    #[rustc_align_static(4096)]
+    static LOCAL: u64 = 0;
+
+    #[allow(unused_mut, reason = "test attribute handling")]
+    #[cfg_attr(true, rustc_align_static(4096))]
+    static CONST_LOCAL: u64 = const { 0 };
+
+    #[cfg_attr(any(true), cfg_attr(true, rustc_align_static(4096)))]
+    #[allow(unused_mut, reason = "test attribute handling")]
+    static HASDROP_LOCAL: Cell<HasDrop> = Cell::new(HasDrop(core::ptr::null()));
+
+    /// I love doc comments.
+    #[allow(unused_mut, reason = "test attribute handling")]
+    #[cfg_attr(all(),
+      cfg_attr(any(true),
+      cfg_attr(true, rustc_align_static(4096))))]
+    #[allow(unused_mut, reason = "test attribute handling")]
+    /// I love doc comments.
+    static HASDROP_CONST_LOCAL: Cell<HasDrop> = const { Cell::new(HasDrop(core::ptr::null())) };
+
+    #[cfg_attr(true,)]
+    #[cfg_attr(false,)]
+    #[cfg_attr(
+        true,
+        rustc_align_static(32),
+        cfg_attr(true, allow(non_upper_case_globals, reason = "test attribute handling")),
+        cfg_attr(false,)
+    )]
+    #[cfg_attr(false, rustc_align_static(0))]
+    static more_attr_testing: u64 = 0;
+}
+
+fn thread_local_ptr<T>(key: &'static std::thread::LocalKey<T>) -> *const T {
+    key.with(|local| core::ptr::from_ref::<T>(local))
+}
+
 fn main() {
     assert!(core::ptr::from_ref(&FOO).addr().is_multiple_of(256));
     assert!(core::ptr::from_ref(&BAR).addr().is_multiple_of(512));
+
+    assert!(thread_local_ptr(&LOCAL).addr().is_multiple_of(4096));
+    assert!(thread_local_ptr(&CONST_LOCAL).addr().is_multiple_of(4096));
+    assert!(thread_local_ptr(&HASDROP_LOCAL).addr().is_multiple_of(4096));
+    assert!(thread_local_ptr(&HASDROP_CONST_LOCAL).addr().is_multiple_of(4096));
+    assert!(thread_local_ptr(&more_attr_testing).addr().is_multiple_of(32));
+
+    // Test that address (and therefore alignment) is maintained during drop
+    let hasdrop_ptr = thread_local_ptr(&HASDROP_LOCAL);
+    core::mem::forget(HASDROP_LOCAL.replace(HasDrop(hasdrop_ptr.cast())));
+    let hasdrop_const_ptr = thread_local_ptr(&HASDROP_CONST_LOCAL);
+    core::mem::forget(HASDROP_CONST_LOCAL.replace(HasDrop(hasdrop_const_ptr.cast())));
 }
-- 
cgit 1.4.1-3-g733a5