Use pointer offset instead of deref for A/Rc::into_raw

rust-lang · Dec 16, 2019 · c842f02 · c842f02
1 parent 7dbfb0a
commit c842f02
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Showing 2 changed files with 14 additions and 4 deletions.
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
@@ -571,9 +571,14 @@ impl<T: ?Sized> Rc<T> {
  /// ```
  #[stable(feature = "rc_raw", since = "1.17.0")]
  pub fn into_raw(this: Self) -> *const T {
- let ptr: *const T = &*this;
+ let ptr: *mut RcBox<T> = NonNull::as_ptr(this.ptr);
+ let fake_ptr = ptr as *mut T;
  mem::forget(this);
- ptr
+
+ unsafe {
+ let offset = data_offset(&(*ptr).value);
+ set_data_ptr(fake_ptr, (ptr as *mut u8).offset(offset))
+ }
  }
 
  /// Constructs an `Rc` from a raw pointer.

diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs
@@ -551,9 +551,14 @@ impl<T: ?Sized> Arc<T> {
  /// ```
  #[stable(feature = "rc_raw", since = "1.17.0")]
  pub fn into_raw(this: Self) -> *const T {
- let ptr: *const T = &*this;
+ let ptr: *mut ArcInner<T> = NonNull::as_ptr(this.ptr);
+ let fake_ptr = ptr as *mut T;
  mem::forget(this);
- ptr
+
+ unsafe {
+ let offset = data_offset(&(*ptr).data);
+ set_data_ptr(fake_ptr, (ptr as *mut u8).offset(offset))
+ }
  }
 
  /// Constructs an `Arc` from a raw pointer.