if let Some(pointee) = layout.pointee_info_at(cx, offset) {
if let Some(kind) = pointee.safe {
- attrs.pointee_size = pointee.size;
attrs.pointee_align = Some(pointee.align);
+ // `Box` (`UniqueBorrowed`) are not necessarily dereferencable
+ // for the entire duration of the function, so set their size to 0.
+ attrs.pointee_size = match kind {
+ PointerKind::UniqueOwned => Size::ZERO,
+ _ => pointee.size
+ };
+
// `Box` pointer parameters never alias because ownership is transferred
// `&mut` pointer parameters never alias other parameters,
// or mutable global data
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub struct ArgAttributes {
pub regular: ArgAttribute,
+ /// The dereferenceable size of the pointee.
pub pointee_size: Size,
pub pointee_align: Option<Align>
}
pub fn borrowed_struct(_: &S) {
}
-// CHECK: noalias align 4 dereferenceable(4) i32* @_box(i32* noalias align 4 dereferenceable(4) %x)
+// `Box` can get deallocated during execution of the function, so it should
+// not get `dereferenceable`.
+// CHECK: noalias nonnull align 4 i32* @_box(i32* noalias nonnull align 4 %x)
#[no_mangle]
pub fn _box(x: Box<i32>) -> Box<i32> {
x