Merge tag 'debian/1.52.1+dfsg1-1_exp2' into proxmox/buster

[rustc.git] / compiler / rustc_arena / src / tests.rs

diff --git a/compiler/rustc_arena/src/tests.rs b/compiler/rustc_arena/src/tests.rs
index e8a1f2db1a16b029b380b4f0004306f0ab43ac63..911e577c1edc7b5b29bea226cd68fbc7c8a80029 100644 (file)
--- a/compiler/rustc_arena/src/tests.rs
+++ b/compiler/rustc_arena/src/tests.rs
@@ -11,6 +11,24 @@ struct Point {
     z: i32,
 }
 
+impl<T> TypedArena<T> {
+    /// Clears the arena. Deallocates all but the longest chunk which may be reused.
+    fn clear(&mut self) {
+        unsafe {
+            // Clear the last chunk, which is partially filled.
+            let mut chunks_borrow = self.chunks.borrow_mut();
+            if let Some(mut last_chunk) = chunks_borrow.last_mut() {
+                self.clear_last_chunk(&mut last_chunk);
+                let len = chunks_borrow.len();
+                // If `T` is ZST, code below has no effect.
+                for mut chunk in chunks_borrow.drain(..len - 1) {
+                    chunk.destroy(chunk.entries);
+                }
+            }
+        }
+    }
+}
+
 #[test]
 pub fn test_unused() {
     let arena: TypedArena<Point> = TypedArena::default();