Fix MIRI with updated MaybeUninit move semantics

rkyv · Sep 11, 2024 · e8fb001 · e8fb001
1 parent b9706b4
commit e8fb001
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Showing 2 changed files with 24 additions and 4 deletions.
diff --git a/rkyv/src/collections/btree_map/mod.rs b/rkyv/src/collections/btree_map/mod.rs
@@ -501,7 +501,12 @@ impl<K, V, const E: usize> ArchivedBTreeMap<K, V, E> {
         }
 
         let pos = serializer.align_for::<LeafNode<K, V, E>>()?;
-        let mut node = MaybeUninit::<LeafNode<K, V, E>>::zeroed();
+        let mut node = MaybeUninit::<LeafNode<K, V, E>>::uninit();
+        // SAFETY: `node` is properly aligned and valid for writes of
+        // `size_of::<LeafNode<K, V, E>>()` bytes.
+        unsafe {
+            node.as_mut_ptr().write_bytes(0, 1);
+        }
 
         let node_place =
             unsafe { Place::new_unchecked(pos, node.as_mut_ptr()) };
@@ -561,7 +566,12 @@ impl<K, V, const E: usize> ArchivedBTreeMap<K, V, E> {
         }
 
         let pos = serializer.align_for::<InnerNode<K, V, E>>()?;
-        let mut node = MaybeUninit::<InnerNode<K, V, E>>::zeroed();
+        let mut node = MaybeUninit::<InnerNode<K, V, E>>::uninit();
+        // SAFETY: `node` is properly aligned and valid for writes of
+        // `size_of::<InnerNode<K, V, E>>()` bytes.
+        unsafe {
+            node.as_mut_ptr().write_bytes(0, 1);
+        }
 
         let node_place =
             unsafe { Place::new_unchecked(pos, node.as_mut_ptr()) };

diff --git a/rkyv/src/ser/writer/mod.rs b/rkyv/src/ser/writer/mod.rs
@@ -121,7 +121,12 @@ pub trait WriterExt<E>: Writer<E> {
         let pos = self.pos();
         debug_assert_eq!(pos & (mem::align_of::<T::Archived>() - 1), 0);
 
-        let mut resolved = mem::MaybeUninit::<T::Archived>::zeroed();
+        let mut resolved = mem::MaybeUninit::<T::Archived>::uninit();
+        // SAFETY: `resolved` is properly aligned and valid for writes of
+        // `size_of::<T::Archived>()` bytes.
+        unsafe {
+            resolved.as_mut_ptr().write_bytes(0, 1);
+        }
         // SAFETY: `resolved.as_mut_ptr()` points to a local zeroed
         // `MaybeUninit`, and so is properly aligned, dereferenceable, and all
         // of its bytes are initialized.
@@ -150,7 +155,12 @@ pub trait WriterExt<E>: Writer<E> {
             0
         );
 
-        let mut resolved = mem::MaybeUninit::<RelPtr<T::Archived>>::zeroed();
+        let mut resolved = mem::MaybeUninit::<RelPtr<T::Archived>>::uninit();
+        // SAFETY: `resolved` is properly aligned and valid for writes of
+        // `size_of::<RelPtr<T::Archived>>()` bytes.
+        unsafe {
+            resolved.as_mut_ptr().write_bytes(0, 1);
+        }
         // SAFETY: `resolved.as_mut_ptr()` points to a local zeroed
         // `MaybeUninit`, and so is properly aligned, dereferenceable, and all
         // of its bytes are initialized.