Windows TLS: ManuallyDrop instead of mem::forget by RalfJung · Pull Request #798...
source link: https://github.com/rust-lang/rust/pull/79893
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Collaborator
rust-highfive commented 10 days ago
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@@ -111,16 +111,13 @@ struct Node {
}
unsafe fn register_dtor(key: Key, dtor: Dtor) {
let mut node = Box::new(Node { key, dtor, next: ptr::null_mut() });
let mut node = ManuallyDrop::new(Box::new(Node { key, dtor, next: ptr::null_mut() }));
oli-obk 10 days ago
Contributor
Since we never drop this anyway, couldn't we also just Box::into_raw here and then compare_exchangeing the raw pointer directly? I guess that would mean node.next = head needs to be (*node).next = head and is now unsafe, so maybe the ManuallyDrop is better, but I am somewhat unhappy with the &mut **node (the previous &mut *node was not better imo). I know we can rely on the deref ops on boxes, but it still seems wrong to me to not be using Box::into_raw when this is technically what we want.
RalfJung 10 days ago
Author
Member
I guess that would mean node.next = head needs to be (*node).next = head and is now unsafe
I went with into_raw first and decided to use ManuallyDrop when I realized this.
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