Implement provenance preserving methods on NonNull #95556
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**Description** Add the `addr`, `with_addr, `map_addr` methods to the `NonNull` type, and map the address type to `NonZeroUsize`. **Motiviation** The `NonNull` type is useful for implementing pointer types which have the 0-niche. It is currently possible to implement these provenance preserving functions by calling `NonNull::as_ptr` and `new_unchecked`. The addition of these methods simply make it more ergonomic to use. **Testing** Added a unit test of a nonnull tagged pointer type. This is based on some real code I have elsewhere, that currently routes the pointer through a `NonZeroUsize` and back out to produce a usable pointer.
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Implement provenance preserving methods on NonNull ### Description Add the `addr`, `with_addr`, `map_addr` methods to the `NonNull` type, and map the address type to `NonZeroUsize`. ### Motivation The `NonNull` type is useful for implementing pointer types which have the 0-niche. It is currently possible to implement these provenance preserving functions by calling `NonNull::as_ptr` and `new_unchecked`. The adding these methods makes it more ergonomic. ### Testing Added a unit test of a non-null tagged pointer type. This is based on some real code I have elsewhere, that currently routes the pointer through a `NonZeroUsize` and back out to produce a usable pointer. I wanted to produce an ideal version of the same tagged pointer struct that preserved pointer provenance. ### Related Extension of APIs proposed in rust-lang#95228 . I can also split this out into a separate tracking issue if that is better (though I may need some pointers on how to do that).
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Implement provenance preserving methods on NonNull ### Description Add the `addr`, `with_addr`, `map_addr` methods to the `NonNull` type, and map the address type to `NonZeroUsize`. ### Motivation The `NonNull` type is useful for implementing pointer types which have the 0-niche. It is currently possible to implement these provenance preserving functions by calling `NonNull::as_ptr` and `new_unchecked`. The adding these methods makes it more ergonomic. ### Testing Added a unit test of a non-null tagged pointer type. This is based on some real code I have elsewhere, that currently routes the pointer through a `NonZeroUsize` and back out to produce a usable pointer. I wanted to produce an ideal version of the same tagged pointer struct that preserved pointer provenance. ### Related Extension of APIs proposed in rust-lang#95228 . I can also split this out into a separate tracking issue if that is better (though I may need some pointers on how to do that).
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Apr 2, 2022
Rollup of 8 pull requests Successful merges: - rust-lang#95354 (Handle rustc_const_stable attribute in library feature collector) - rust-lang#95373 (invalid_value lint: detect invalid initialization of arrays) - rust-lang#95430 (Disable #[thread_local] support on i686-pc-windows-msvc) - rust-lang#95544 (Add error message suggestion for missing noreturn in naked function) - rust-lang#95556 (Implement provenance preserving methods on NonNull) - rust-lang#95557 (Fix `thread_local!` macro to be compatible with `no_implicit_prelude`) - rust-lang#95559 (small type system refactoring) - rust-lang#95560 (convert more `DefId`s to `LocalDefId`) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
RalfJung
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Apr 3, 2022
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| /// Creates a new pointer by mapping `self`'s address to a new one. | ||
| /// | ||
| /// This is a convenience for [`with_addr`][Self::with_addr], see that method for details. |
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Might be good to have a similar reference in the addr and with_addr docs?
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Do you mean references to the ptr::addr and ptr::with_addr from the NonNull versions? I can make a followup CR
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Yes, that's what I mean. That would be great. :)
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Description
Add the
addr,with_addr,map_addrmethods to theNonNulltype, and map the address type toNonZeroUsize.Motivation
The
NonNulltype is useful for implementing pointer types which have the 0-niche. It is currently possible to implement these provenance preserving functions by callingNonNull::as_ptrandnew_unchecked. The adding these methods makes it more ergonomic.Testing
Added a unit test of a non-null tagged pointer type. This is based on some real code I have elsewhere, that currently routes the pointer through a
NonZeroUsizeand back out to produce a usable pointer. I wanted to produce an ideal version of the same tagged pointer struct that preserved pointer provenance.Related
Extension of APIs proposed in #95228 . I can also split this out into a separate tracking issue if that is better (though I may need some pointers on how to do that).