Commit Graph

2643 Commits

Author SHA1 Message Date
Zalathar 6f1944d394 Document some alternatives to Vec::split_off 2024-01-21 11:56:55 +11:00
Guillaume Gomez b917753d79 Rollup merge of #120116 - the8472:only-same-alignments, r=cuviper
Remove alignment-changing in-place collect

This removes the alignment-changing in-place collect optimization introduced in #110353
Currently stable users can't benefit from the optimization because GlobaAlloc doesn't support alignment-changing realloc and neither do most posix allocators. So in practice it has a negative impact on performance.

Explanation from https://github.com/rust-lang/rust/issues/120091#issuecomment-1899071681:

> > You mention that in case of alignment mismatch -- when the new alignment is less than the old -- the implementation calls `mremap`.
>
> I was trying to note that this isn't really the case in practice, due to the semantics of Rust's allocator APIs. The only use of the allocator within the `in_place_collect` implementation itself is [a call to `Allocator::shrink()`](https://github.com/rust-lang/rust/blob/db7125f008cfd72e8951c9a863178956e2cbacc3/library/alloc/src/vec/in_place_collect.rs#L299-L303), which per its documentation [allows decreasing the required alignment](https://doc.rust-lang.org/1.75.0/core/alloc/trait.Allocator.html). However, in stable Rust, the only available `Allocator` is [`Global`](https://doc.rust-lang.org/1.75.0/alloc/alloc/struct.Global.html), which delegates to the registered `GlobalAlloc`. Since `GlobalAlloc::realloc()` [cannot change the required alignment](https://doc.rust-lang.org/1.75.0/core/alloc/trait.GlobalAlloc.html#method.realloc), the implementation of [`<Global as Allocator>::shrink()`](https://github.com/rust-lang/rust/blob/db7125f008cfd72e8951c9a863178956e2cbacc3/library/alloc/src/alloc.rs#L280-L321) must fall back to creating a brand-new allocation, `memcpy`ing the data into it, and freeing the old allocation, whenever the alignment doesn't remain exactly the same.
>
> Therefore, the underlying allocator, provided by libc or some other source, has no opportunity to internally `mremap()` the data when the alignment is changed, since it has no way of knowing that the allocation is the same.
2024-01-20 20:06:35 +01:00
Tomás Vallotton 180c68bef5 doc: fix some doctests after rebase 2024-01-20 10:26:25 -03:00
Tomás Vallotton 038c6e046c refactor: make waker mandatory.
This also removes
* impl From<&Context> for ContextBuilder
* Context::try_waker()

The from implementation is removed because now that
wakers are always supported, there are less incentives
to override the current context. Before, the incentive
was to add Waker support to a reactor that didn't have
any.
2024-01-20 10:16:09 -03:00
tvallotton c67a446e72 fix: Apply suggestions from code review
Co-authored-by: Mark Rousskov <mark.simulacrum@gmail.com>
2024-01-20 10:14:25 -03:00
Tomás Vallotton 093f80ba7e chore: fix ci failures 2024-01-20 10:14:25 -03:00
Tomás Vallotton 0cb7a0a90e chore: add tracking issue number to local waker feature 2024-01-20 10:14:25 -03:00
Tomás Vallotton 2012d4b703 fix: make LocalWake available in targets that don't support atomics by removing a #[cfg(target_has_atomic = ptr)] 2024-01-20 10:14:25 -03:00
Tomás Vallotton 403718b19d feat: add try_waker and From<&mut Context> for ContextBuilder to allow the extention of contexts by futures 2024-01-20 10:14:21 -03:00
Tomás Vallotton 60a08196b6 feat: add LocalWaker type, ContextBuilder type, and LocalWake trait. 2024-01-20 10:13:08 -03:00
The 8472 5796b3c167 fix: Drop guard was deallocating with the incorrect size
InPlaceDstBufDrop holds onto the allocation before the shrinking happens
which means it must deallocate the destination elements but the source
allocation.
2024-01-19 23:05:30 +01:00
Matthias Krüger 7219bd22ed Rollup merge of #120110 - invpt:patch-1, r=the8472
Update documentation for Vec::into_boxed_slice to be more clear about excess capacity

Currently, the documentation for Vec::into_boxed_slice says that "if the vector has excess capacity, its items will be moved into a newly-allocated buffer with exactly the right capacity." This is misleading, as copies do not necessarily occur, depending on if the allocator supports in-place shrinking. I copied some of the wording from shrink_to_fit, though it could potentially still be worded better than this.
2024-01-19 08:15:05 +01:00
invpt 35a9fc3472 Clarify docs for Vec::into_boxed_slice, Vec::shrink_to_fit 2024-01-18 18:01:36 -05:00
The 8472 85d1787962 remove alignment-changing in-place collect
Currently stable users can't benefit from this because GlobaAlloc doesn't support
alignment-changing realloc and neither do most posix allocators.
So in practice it always results in an extra memcpy.
2024-01-18 22:50:14 +01:00
The 8472 b28a95391b update internal ASCII art comment for vec specializations 2024-01-18 22:47:20 +01:00
Jake Goulding fb7762b1c5 Remove no-longer-needed allow(dead_code) from the standard library
`repr(transparent)` now silences the lint.
2024-01-18 13:14:42 -05:00
zetanumbers 656a38830b Add A: 'static bound for Arc/Rc::pin_in 2024-01-18 14:28:39 +03:00
Robert Grosse db7125f008 Fix typo in comments (in_place_collect) 2024-01-16 20:48:22 -08:00
joboet fa9a911a57 libs: use assert_unchecked instead of intrinsic 2024-01-13 20:10:00 +01:00
Zalathar a655558b38 Remove special-case handling of vec.split_off(0) 2024-01-13 17:21:54 +11:00
Matthias Krüger b3d15ebb08 Rollup merge of #119853 - klensy:rustfmt-ignore, r=cuviper
rustfmt.toml: don't ignore just any tests path, only root one

Previously ignored any `tests` path, now only /tests at repo root.

For reference, https://git-scm.com/docs/gitignore#_pattern_format
2024-01-11 19:42:53 +01:00
klensy aa696c5a22 apply fmt 2024-01-11 15:04:48 +03:00
hi-rustin 784b50cece chore: remove unnecessary blank line
Signed-off-by: hi-rustin <rustin.liu@gmail.com>
2024-01-11 09:45:21 +08:00
The8472 37d26c719d Implement in-place iteratation markers for iter::{Copied, Cloned} 2024-01-10 19:03:57 +01:00
zachs18 bfe04e08c0 Fix deallocation with wrong allocator in (A)Rc::from_box_in 2024-01-10 02:17:47 -06:00
Taiki Endo 4e973b0b63 rc,sync: Do not create references to uninitialized values 2024-01-08 00:36:31 +09:00
The 8472 93b34a5ffa mark vec::IntoIter pointers as !nonnull 2024-01-07 03:44:04 +01:00
The 8472 fd8ba7bc3c typo fix 2024-01-07 03:42:45 +01:00
Matthias Krüger 923578e6f9 Rollup merge of #118781 - RalfJung:core-panic-feature, r=the8472
merge core_panic feature into panic_internals

I don't know why those are two separate features, but it does not seem intentional. This merge is useful because with https://github.com/rust-lang/rust/pull/118123, panic_internals is recognized as an internal feature, but core_panic is not -- but core_panic definitely should be internal.
2024-01-06 16:07:46 +01:00
bors 5113ed28ea Auto merge of #118297 - shepmaster:warn-dead-tuple-fields, r=WaffleLapkin
Merge `unused_tuple_struct_fields` into `dead_code`

This implicitly upgrades the lint from `allow` to `warn` and places it into the `unused` lint group.

[Discussion on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Moving.20.60unused_tuple_struct_fields.60.20from.20allow.20to.20warn)
2024-01-05 04:51:55 +00:00
León Orell Valerian Liehr 34ef194859 Rollup merge of #119434 - taiki-e:rc-is-dangling, r=Mark-Simulacrum
rc: Take *const T in is_dangling

It is not important which one is used since `is_dangling` does not access memory, but `*const` removes the needs of `*const T` -> `*mut T` casts in `from_raw_in`.
2024-01-03 16:08:25 +01:00
Jake Goulding 5772818dc8 Adjust library tests for unused_tuple_struct_fields -> dead_code 2024-01-02 15:34:37 -05:00
Matthias Krüger c67ab2e0b4 Rollup merge of #119158 - JohnTheCoolingFan:arc-weak-clone-pretty, r=cuviper
Clean up alloc::sync::Weak Clone implementation

Since both return points (tail and early return) return the same expression and the only difference is whether inner is available, the code that does the atomic operations and checks on inner was moved into the if body and the only return is at the tail. Original comments preserved.
2023-12-30 11:42:02 +01:00
Taiki Endo 2c23c06c32 rc: Take *const T in is_dangling
It is not important which one is used since `is_dangling` does not access
memory, but `*const` removes the needs of `*const T` -> `*mut T` casts
in `from_raw_in`.
2023-12-30 16:28:00 +09:00
Gurinder Singh e3aca01343 Italicise "bytes" in the docs of some Vec methods
because on a cursory read it's easy to miss that the limit is
in terms of bytes not no. of elements. The italics should help
with that.
2023-12-29 09:53:29 +05:30
Matthias Krüger 89c3236789 Rollup merge of #119205 - mumbleskates:vecdeque-comment-fix, r=Mark-Simulacrum
fix minor mistake in comments describing VecDeque resizing

Avoiding confusion where one of the items in the deque seems to disappear in two of the three cases
2023-12-24 01:08:09 +01:00
Pietro Albini c00486c9bb update version placeholders 2023-12-22 11:01:42 +01:00
Kent Ross f2e711e4c2 fix minor mistake in comments describing VecDeque resizing 2023-12-21 15:20:14 -08:00
JohnTheCoolingFan 0453d5fe6f Cleaned up alloc::sync::Weak Clone implementation
Since both return points (tail and early return) return the same
expression and the only difference is whether inner is available, the
code that does the atomic operations and checks on inner was moved into
the if body and the only return is at the tail. Original comments
preserved.
2023-12-20 12:13:34 +03:00
bors 51c0db6a91 Auto merge of #106790 - the8472:rawvec-niche, r=scottmcm
add more niches to rawvec

Previously RawVec only had a single niche in its `NonNull` pointer. With this change it now has `isize::MAX` niches since half the value-space of the capacity field is never needed, we can't have a capacity larger than isize::MAX.
2023-12-20 02:19:10 +00:00
Daniel Huang f2f9b1d82a Update c_str.rs 2023-12-14 19:08:36 -05:00
The 8472 6a2f44e9d8 add comment to RawVec::cap field 2023-12-11 23:38:48 +01:00
The 8472 502df1b7d4 add more niches to rawvec 2023-12-11 23:38:48 +01:00
bors 8a3765582c Auto merge of #117758 - Urgau:lint_pointer_trait_comparisons, r=davidtwco
Add lint against ambiguous wide pointer comparisons

This PR is the resolution of https://github.com/rust-lang/rust/issues/106447 decided in https://github.com/rust-lang/rust/issues/117717 by T-lang.

## `ambiguous_wide_pointer_comparisons`

*warn-by-default*

The `ambiguous_wide_pointer_comparisons` lint checks comparison of `*const/*mut ?Sized` as the operands.

### Example

```rust
let ab = (A, B);
let a = &ab.0 as *const dyn T;
let b = &ab.1 as *const dyn T;

let _ = a == b;
```

### Explanation

The comparison includes metadata which may not be expected.

-------

This PR also drops `clippy::vtable_address_comparisons` which is superseded by this one.

~~One thing: is the current naming right? `invalid` seems a bit too much.~~

Fixes https://github.com/rust-lang/rust/issues/117717
2023-12-11 14:33:16 +00:00
bors 84f6130fe3 Auto merge of #118692 - surechen:remove_unused_imports, r=petrochenkov
remove redundant imports

detects redundant imports that can be eliminated.

for #117772 :

In order to facilitate review and modification, split the checking code and removing redundant imports code into two PR.

r? `@petrochenkov`
2023-12-10 11:55:48 +00:00
bors 61afc9c928 Auto merge of #116949 - hamza1311:stablize-arc_unwrap_or_clone, r=dtolnay
Stablize arc_unwrap_or_clone

Fixes: #93610

This likely needs FCP. I created this PR as it's stabilization is trivial and FCP can be just conducted here. Not sure how to ping the libs API team (last attempt didn't work apparently according to GH UI)
2023-12-10 05:01:00 +00:00
surechen 40ae34194c remove redundant imports
detects redundant imports that can be eliminated.

for #117772 :

In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
2023-12-10 10:56:22 +08:00
Ralf Jung af4913fcf4 merge core_panic feature into panic_internals 2023-12-09 14:49:00 +01:00
bors 1a3aa4ad14 Auto merge of #114136 - TennyZhuang:linked-list-retain, r=thomcc
add LinkedList::{retain,retain_mut}

Implement #114135

The API is consistent with other collections.
2023-12-09 02:38:45 +00:00
bors c9d85d67c4 Auto merge of #117960 - zhiqiangxu:dry, r=workingjubilee
chore: avoid duplicate code in `Weak::inner`
2023-12-07 02:27:41 +00:00