This PR is an implementation of [RFC 1974] which specifies a new method of
defining a global allocator for a program. This obsoletes the old
`#![allocator]` attribute and also removes support for it.
[RFC 1974]: https://github.com/rust-lang/rfcs/pull/197
The new `#[global_allocator]` attribute solves many issues encountered with the
`#![allocator]` attribute such as composition and restrictions on the crate
graph itself. The compiler now has much more control over the ABI of the
allocator and how it's implemented, allowing much more freedom in terms of how
this feature is implemented.
cc #27389
It was decided in the RFC discussion https://github.com/rust-lang/rfcs/pull/1954 to make the function call syntax Rc::clone(&foo) the idiomatic way to clone a reference counted pointer (over the method call syntax foo.clone(). This change updates the documentation of Rc, Arc and their respoective Weak pointers to reflect it and bring more exposure to the existence of the function call syntax.
refactor NonZero, Shared, and Unique APIs
Major difference is that I removed Deref impls, as apparently LLVM has
trouble maintaining metadata with a `&ptr -> &ptr` API. This was cited
as a blocker for ever stabilizing this API. It wasn't that ergonomic
anyway.
* Added `get` to NonZero to replace Deref impl
* Added `ptr` getter to Shared/Unique to replace Deref impl
* Added Unique's `get` and `get_mut` conveniences to Shared
* Deprecated `as_mut_ptr` on Shared in favour of `ptr`
Note that Shared used to primarily expose only `*const` but there isn't
a good justification for that, so I made it `*mut`.
This reverts commit 7f1d1c6d9a.
The original commit was created because mdBook and rustdoc had
different generation algorithms for header links; now with
https://github.com/rust-lang/rust/pull/39966 , the algorithms
are the same. So let's undo this change.
... when I came across this problem, I said "eh, this isn't fun,
but it doesn't take that long." I probably should have just actually
taken the time to fix upstream, given that they were amenable. Oh
well!
Add `{into,from}_raw` to Rc and Arc
These methods convert to and from a `*const T` for `Rc` and `Arc` similar to the way they work on `Box`. The only slight complication is that `from_raw` needs to offset the pointer back to find the beginning of the `RcBox`/`ArcInner`.
I felt this is a fairly small addition, filling in a gap (when compared to `Box`) so it wouldn't need an RFC. The motivation is primarily for FFI.
(I'll create an issue and update a PR with the issue number if reviewers agree with the change in principle **Edit: done #37197**)
~~Edit: This was initially `{into,from}_raw` but concerns were raised about the possible footgun if mixed with the methods of the same name of `Box`.~~
Edit: This was went from `{into,from}_raw` to `{into,from}_inner_raw` then back to `{into,from}_raw` during review.
The constant name `MAX_REFCOUNT` suggests that the value is a
_hard_ limit on the amount of references to an `Arc`. This is
a more soft limit however. This commit adds a comment to the
constant to annotate this.
See also: PR #37605
Long ago we discovered that threads which outlive main and then exit while the
rest of the program is exiting causes Windows to hang (#20704). That's what was
happening in this test so let's just not run this test any more.
This allows printing pointers to unsized types with the {:p} formatting
directive. The following impls are extended to unsized types:
- impl<'a, T: ?Sized> Pointer for &'a T
- impl<'a, T: ?Sized> Pointer for &'a mut T
- impl<T: ?Sized> Pointer for *const T
- impl<T: ?Sized> Pointer for *mut T
- impl<T: ?Sized> fmt::Pointer for Box<T>
- impl<T: ?Sized> fmt::Pointer for Rc<T>
- impl<T: ?Sized> fmt::Pointer for Arc<T>
This allows printing pointers to unsized types with the {:p} formatting
directive. The following impls are extended to unsized types:
- impl<'a, T: ?Sized> Pointer for &'a T
- impl<'a, T: ?Sized> Pointer for &'a mut T
- impl<T: ?Sized> Pointer for *const T
- impl<T: ?Sized> Pointer for *mut T
- impl<T: ?Sized> fmt::Pointer for Box<T>
- impl<T: ?Sized> fmt::Pointer for Rc<T>
- impl<T: ?Sized> fmt::Pointer for Arc<T>
Changed the description of the `make_mut` copy-on-write behaviour in arc.rs
The sentence "doesn't have one strong reference and no weak references." is a
hard to understand double negative, which can be much more easily explained.
