clarify that realloc refreshes pointer provenance even when the allocation remains in-place
This [matches what C does](https://en.cppreference.com/w/c/memory/realloc):
> The original pointer ptr is invalidated and any access to it is undefined behavior (even if reallocation was in-place).
Cc `@rust-lang/wg-allocators`
`VecDeque::resize` should re-use the buffer in the passed-in element
Today it always copies it for *every* appended element, but one of those clones is avoidable.
This adds `iter::repeat_n` (https://github.com/rust-lang/rust/issues/104434) as the primitive needed to do this. If this PR is acceptable, I'll also use this in `Vec` rather than its custom `ExtendElement` type & infrastructure that is harder to share between multiple different containers:
101e1822c3/library/alloc/src/vec/mod.rs (L2479-L2492)
* Fix doc examples for Platforms with underaligned integer primitives.
* Mutable pointer doc examples use mutable pointers.
* Fill out tracking issue.
* Minor formatting changes.
Rollup of 10 pull requests
Successful merges:
- #103117 (Use `IsTerminal` in place of `atty`)
- #103969 (Partial support for running UI tests with `download-rustc`)
- #103989 (Fix build of std for thumbv7a-pc-windows-msvc)
- #104076 (fix sysroot issue which appears for ci downloaded rustc)
- #104469 (Make "long type" printing type aware and trim types in E0275)
- #104497 (detect () to avoid redundant <> suggestion for type)
- #104577 (Don't focus on notable trait parent when hiding it)
- #104587 (Update cargo)
- #104593 (Improve spans for RPITIT object-safety errors)
- #104604 (Migrate top buttons style to CSS variables)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix build of std for thumbv7a-pc-windows-msvc
Attempting to build std for the tier-3 target `thumbv7a-pc-windows-msvc` fails with the following error:
```
Building stage1 std artifacts (x86_64-pc-windows-msvc -> thumbv7a-pc-windows-msvc)
..
LLVM ERROR: WinEH not implemented for this target
error: could not compile `panic_unwind`
```
EH (unwinding) is not supported by LLVM for 32 bit arm msvc targets. This changes panic unwind to use the dummy implementation for `thumbv7a-pc-windows-msvc`.
Revert Vec/Rc storage reuse opt
Remove the optimization for using storage added by #104205.
The perf wins were pretty small, and it relies on non-guarenteed behaviour. On platforms that don't implement shrinking in place, the performance will be significantly worse.
While it could be gated to platforms that do this (such as GNU), I don't think it's worth the overhead of maintaining it for very small gains. (#104565, #104563)
cc `@RalfJung` `@matthiaskrgr`
Fixes#104565Fixes#104563
Improve accuracy of asinh and acosh
This PR addresses the inaccuracy of `asinh` and `acosh` identified by the [Herbie](http://herbie.uwplse.org/) tool, `@pavpanchekha,` `@finnbear` in #104548. It also adds a couple tests that failed in the existing implementations and now pass.
Closes#104548
r? rust-lang/libs
Rollup of 8 pull requests
Successful merges:
- #102977 (remove HRTB from `[T]::is_sorted_by{,_key}`)
- #103378 (Fix mod_inv termination for the last iteration)
- #103456 (`unchecked_{shl|shr}` should use `u32` as the RHS)
- #103701 (Simplify some pointer method implementations)
- #104047 (Diagnostics `icu4x` based list formatting.)
- #104338 (Enforce that `dyn*` coercions are actually pointer-sized)
- #104498 (Edit docs for `rustc_errors::Handler::stash_diagnostic`)
- #104556 (rustdoc: use `code-header` class to format enum variants)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Enforce that `dyn*` coercions are actually pointer-sized
Implement a perma-unstable, rudimentary `PointerSized` trait to enforce `dyn*` casts are `usize`-sized for now, at least to prevent ICEs and weird codegen issues from cropping up after monomorphization since currently we enforce *nothing*.
This probably can/should be removed in favor of a more sophisticated trait for handling `dyn*` conversions when we decide on one, but I just want to get something up for discussion and experimentation for now.
r? ```@eholk``` cc ```@tmandry``` (though feel free to claim/reassign)
Fixes#102141Fixes#102173
Simplify some pointer method implementations
- Make `pointer::with_metadata_of` const (+simplify implementation) (cc #75091)
- Simplify implementation of various pointer methods
r? ```@scottmcm```
----
`from_raw_parts::<T>(this, metadata(self))` was annoying me for a while and I've finally figured out how it should _actually_ be done.
Fix mod_inv termination for the last iteration
On usize=u64 platforms, the 4th iteration would overflow the `mod_gate` back to 0. Similarly for usize=u32 platforms, the 3rd iteration would overflow much the same way.
I tested various approaches to resolving this, including approaches with `saturating_mul` and `widening_mul` to a double usize. Turns out LLVM likes `mul_with_overflow` the best. In fact now, that LLVM can see the iteration count is limited, it will happily unroll the loop into a nice linear sequence.
You will also notice that the code around the loop got simplified somewhat. Now that LLVM is handling the loop nicely, there isn’t any more reasons to manually unroll the first iteration out of the loop (though looking at the code today I’m not sure all that complexity was necessary in the first place).
Fixes#103361
Fix non-associativity of `Instant` math on `aarch64-apple-darwin` targets
This is a duplicate of #94100 (since the original author is unresponsive), which resolves#91417.
On `aarch64-apple-darwin` targets, the internal resolution of `Instant` is lower than that of `Duration`, so math between them becomes non-associative with small-enough durations.
This PR makes this target use the standard Unix implementation (where `Instant` has 1ns resolution), but with `CLOCK_UPTIME_RAW` so it still returns the same values as `mach_absolute_time`[^1].
(Edit: I need someone to confirm that this still works, I do not have access to an M1 device.)
[^1]: https://www.manpagez.com/man/3/clock_gettime/
Support `#[track_caller]` on async fns
Adds `#[track_caller]` to the generator that is created when we desugar the async fn.
Fixes#78840
Open questions:
- What is the performance impact of adding `#[track_caller]` to every `GenFuture`'s `poll(...)` function, even if it's unused (i.e., the parent span does not set `#[track_caller]`)? We might need to set it only conditionally, if the indirection causes overhead we don't want.
