]> git.lizzy.rs Git - rust.git/log
rust.git
3 years agoAuto merge of #76217 - RalfJung:maybe-uninit-slice, r=KodrAus
bors [Sat, 5 Sep 2020 21:02:18 +0000 (21:02 +0000)]
Auto merge of #76217 - RalfJung:maybe-uninit-slice, r=KodrAus

rename MaybeUninit slice methods

The `first` methods conceptually point to the whole slice, not just its first element, so rename them to be consistent with the raw ptr methods on ref-slices.

Also, do the equivalent of https://github.com/rust-lang/rust/pull/76047 for the slice reference getters, and make them part of https://github.com/rust-lang/rust/issues/63569 (so far they somehow had no tracking issue).

* first_ptr -> slice_as_ptr
* first_ptr_mut -> slice_as_mut_ptr
* slice_get_ref -> slice_assume_init_ref
* slice_get_mut -> slice_assume_init_mut

3 years agoAuto merge of #75428 - the8472:fix-copy-eopnotsupp, r=joshtriplett
bors [Sat, 5 Sep 2020 19:09:22 +0000 (19:09 +0000)]
Auto merge of #75428 - the8472:fix-copy-eopnotsupp, r=joshtriplett

Workarounds for copy_file_range issues

fixes #75387
fixes #75446

3 years agoAuto merge of #75872 - mati865:pgo-tests, r=petrochenkov
bors [Sat, 5 Sep 2020 17:18:26 +0000 (17:18 +0000)]
Auto merge of #75872 - mati865:pgo-tests, r=petrochenkov

Enable some of profiler tests on Windows-gnu

CC https://github.com/rust-lang/rust/issues/61266

Because of force-push GitHub didn't let me reopen https://github.com/rust-lang/rust/pull/75184

Because of the GCC miscompilation, generated binaries either segfault or `.profraw` is malformed. Clang works fine but we can't use it on the CI.
However we can still test the IR for the proper instrumentation so let's do it.

3 years agodocument remaining unsafety in maybe_uninit.rs
Ralf Jung [Wed, 2 Sep 2020 08:00:08 +0000 (10:00 +0200)]
document remaining unsafety in maybe_uninit.rs

3 years agorename MaybeUninit slice methods
Ralf Jung [Tue, 1 Sep 2020 21:16:51 +0000 (23:16 +0200)]
rename MaybeUninit slice methods

first_ptr -> slice_as_ptr
first_ptr_mut -> slice_as_mut_ptr
slice_get_ref -> slice_assume_init_ref
slice_get_mut -> slice_assume_init_mut

3 years agoAuto merge of #76376 - Dylan-DPC:rollup-8chsbw9, r=Dylan-DPC
bors [Sat, 5 Sep 2020 14:59:32 +0000 (14:59 +0000)]
Auto merge of #76376 - Dylan-DPC:rollup-8chsbw9, r=Dylan-DPC

Rollup of 11 pull requests

Successful merges:

 - #75695 (Add a regression test for issue-72793)
 - #75741 (Refactor byteorder to std in rustc_middle)
 - #75954 (Unstable Book: add links to tracking issues for FFI features)
 - #75994 (`impl Rc::new_cyclic`)
 - #76060 (Link vec doc to & reference)
 - #76078 (Remove disambiguators from intra doc link text)
 - #76082 (Fix intra-doc links on pub re-exports)
 - #76254 (Fold length constant in Rvalue::Repeat)
 - #76258 (x.py check checks tests/examples/benches)
 - #76263 (inliner: Check for codegen fn attributes compatibility)
 - #76285 (Move jointness censoring to proc_macro)

Failed merges:

r? @ghost

3 years agoRollup merge of #76285 - matklad:censor-spacing, r=petrochenkov
Dylan DPC [Sat, 5 Sep 2020 14:28:36 +0000 (16:28 +0200)]
Rollup merge of #76285 - matklad:censor-spacing, r=petrochenkov

Move jointness censoring to proc_macro

Proc-macro API currently exposes jointness in `Punct` tokens. That is,
`+` in `+one` is **non** joint.

Our lexer produces jointness info for all tokens, so we need to censor
it *somewhere*

Previously we did this in a lexer, but it makes more sense to do this
in a proc-macro server.

r? @petrochenkov

3 years agoRollup merge of #76263 - tmiasko:inline-codegen-fn-attrs, r=ecstatic-morse
Dylan DPC [Sat, 5 Sep 2020 14:28:34 +0000 (16:28 +0200)]
Rollup merge of #76263 - tmiasko:inline-codegen-fn-attrs, r=ecstatic-morse

inliner: Check for codegen fn attributes compatibility

* Check for target features compatibility
* Check for no_sanitize attribute compatibility

Fixes #76259.

3 years agoRollup merge of #76258 - Mark-Simulacrum:check-tests, r=ehuss
Dylan DPC [Sat, 5 Sep 2020 14:28:32 +0000 (16:28 +0200)]
Rollup merge of #76258 - Mark-Simulacrum:check-tests, r=ehuss

x.py check checks tests/examples/benches

This also adds a check for bootstrap to x.py.

r? @ehuss

3 years agoRollup merge of #76254 - tmiasko:fold-len, r=wesleywiser
Dylan DPC [Sat, 5 Sep 2020 14:28:30 +0000 (16:28 +0200)]
Rollup merge of #76254 - tmiasko:fold-len, r=wesleywiser

Fold length constant in Rvalue::Repeat

Fixes #76248.

3 years agoRollup merge of #76082 - jyn514:top-level-links, r=ollie27,GuillaumeGomez
Dylan DPC [Sat, 5 Sep 2020 14:28:28 +0000 (16:28 +0200)]
Rollup merge of #76082 - jyn514:top-level-links, r=ollie27,GuillaumeGomez

Fix intra-doc links on pub re-exports

Partial fix for https://github.com/rust-lang/rust/issues/76073 - This removes the incorrect error, but doesn't show the documentation anywhere.
r? @GuillaumeGomez

3 years agoRollup merge of #76078 - jyn514:no-disambiguator, r=manishearth
Dylan DPC [Sat, 5 Sep 2020 14:28:26 +0000 (16:28 +0200)]
Rollup merge of #76078 - jyn514:no-disambiguator, r=manishearth

Remove disambiguators from intra doc link text

Closes https://github.com/rust-lang/rust/issues/65354.
r? @Manishearth

The commits are mostly atomic, but there might be some mix between them here and there. I recommend reading 'refactor ItemLink' and 'refactor RenderedLink' on their own though, lots of churn without any logic changes.

3 years agoRollup merge of #76060 - pickfire:patch-12, r=jyn514
Dylan DPC [Sat, 5 Sep 2020 14:28:24 +0000 (16:28 +0200)]
Rollup merge of #76060 - pickfire:patch-12, r=jyn514

Link vec doc to & reference

It is not always obvious that people could see the docs for `&`
especially for beginners, it also helps learnability.

3 years agoRollup merge of #75994 - mental32:impl-rc-new-cyclic, r=KodrAus
Dylan DPC [Sat, 5 Sep 2020 14:28:22 +0000 (16:28 +0200)]
Rollup merge of #75994 - mental32:impl-rc-new-cyclic, r=KodrAus

`impl Rc::new_cyclic`

References #75861

r? @Dylan-DPC

3 years agoRollup merge of #75954 - ArekPiekarz:unstable_book_ffi_tracking_issues, r=steveklabnik
Dylan DPC [Sat, 5 Sep 2020 14:28:20 +0000 (16:28 +0200)]
Rollup merge of #75954 - ArekPiekarz:unstable_book_ffi_tracking_issues, r=steveklabnik

Unstable Book: add links to tracking issues for FFI features

3 years agoRollup merge of #75741 - workingjubilee:refactor-byteorder, r=matthewjasper
Dylan DPC [Sat, 5 Sep 2020 14:28:17 +0000 (16:28 +0200)]
Rollup merge of #75741 - workingjubilee:refactor-byteorder, r=matthewjasper

Refactor byteorder to std in rustc_middle

Use std::io::{Read, Write} and {to, from}_{le, be}_bytes methods in
order to remove byteorder from librustc_middle's dependency graph.

3 years agoRollup merge of #75695 - JohnTitor:regression-test, r=Dylan-DPC
Dylan DPC [Sat, 5 Sep 2020 14:28:16 +0000 (16:28 +0200)]
Rollup merge of #75695 - JohnTitor:regression-test, r=Dylan-DPC

Add a regression test for issue-72793

Adds a regression test for #72793, which is fixed by #75443. Note that this won't close the issue as the snippet still shows ICE with `-Zmir-opt-level=2`. But it makes sense to add a test anyway.

3 years agoAuto merge of #75584 - RalfJung:union-no-deref, r=matthewjasper
bors [Sat, 5 Sep 2020 11:47:01 +0000 (11:47 +0000)]
Auto merge of #75584 - RalfJung:union-no-deref, r=matthewjasper

do not apply DerefMut on union field

This implements the part of [RFC 2514](https://github.com/rust-lang/rfcs/blob/master/text/2514-union-initialization-and-drop.md) about `DerefMut`. Unlike described in the RFC, we only apply this warning specifically when doing `DerefMut` of a `ManuallyDrop` field; that is really the case we are worried about here.

@matthewjasper suggested I patch `convert_place_derefs_to_mutable` and `convert_place_op_to_mutable` for this, but I could not find anything to do in `convert_place_op_to_mutable` and this is sufficient to make the test pass. However, maybe there are some other cases this misses? I have no familiarity with this code.

This is a breaking change *in theory*, if someone used `ManuallyDrop<T>` in a union field and relied on automatic `DerefMut`. But on stable this means `T: Copy`, so the `ManuallyDrop` is rather pointless.

Cc https://github.com/rust-lang/rust/issues/55149

3 years agoUpdate llvm submodule
Mateusz Mikuła [Mon, 31 Aug 2020 12:42:26 +0000 (14:42 +0200)]
Update llvm submodule

3 years agoIgnore failing PGO/coverage tests on MinGW
Mateusz Mikuła [Mon, 24 Aug 2020 09:58:04 +0000 (11:58 +0200)]
Ignore failing PGO/coverage tests on MinGW

3 years agoAuto merge of #75888 - GuillaumeGomez:trait-impl-assoc-const-doc-alias, r=ollie27
bors [Sat, 5 Sep 2020 09:35:17 +0000 (09:35 +0000)]
Auto merge of #75888 - GuillaumeGomez:trait-impl-assoc-const-doc-alias, r=ollie27

Add check for doc alias on assoc const in trait impl

Fixes #73721.

r? @ollie27

3 years agoFix big endian read/write
Jubilee Young [Sat, 22 Aug 2020 10:54:15 +0000 (03:54 -0700)]
Fix big endian read/write

Co-authored-by: matthewjasper <mjjasper1@gmail.com>
3 years agoExplain contract of {read, write}_target_uint
Jubilee Young [Fri, 21 Aug 2020 07:55:33 +0000 (00:55 -0700)]
Explain contract of {read, write}_target_uint

3 years agoBe explicit that we're handling bytes
Jubilee [Thu, 20 Aug 2020 22:55:02 +0000 (15:55 -0700)]
Be explicit that we're handling bytes

Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>
3 years agoRemove reference to byteorder limits
Jubilee Young [Thu, 20 Aug 2020 12:32:14 +0000 (05:32 -0700)]
Remove reference to byteorder limits

3 years agoRefactor byteorder to std in rustc_middle
Jubilee Young [Thu, 20 Aug 2020 09:37:00 +0000 (02:37 -0700)]
Refactor byteorder to std in rustc_middle

Use std::io::{Read, Write} and {to, from}_{le, be}_bytes methods in
order to remove byteorder from librustc_middle's dependency graph.

3 years agoAuto merge of #75173 - jackh726:chalk-0.21, r=nikomatsakis
bors [Sat, 5 Sep 2020 02:24:05 +0000 (02:24 +0000)]
Auto merge of #75173 - jackh726:chalk-0.21, r=nikomatsakis

Upgrade Chalk to 0.21

Two commits here. First commit actually does the upgrade. Second commit has some changes to make more tests in compare-mode=chalk pass.

The `PlaceholdersCollector` and `RegionsSubstitutor` bits are bit a hacky, but only insomuch as `ParamsSubstitutor` is. These won't be needed eventually.

r? @nikomatsakis

3 years agokind -> kind()
Jack Huey [Fri, 4 Sep 2020 23:17:57 +0000 (19:17 -0400)]
kind -> kind()

3 years agoAuto merge of #75200 - ssomers:btree_valmut, r=Mark-Simulacrum
bors [Fri, 4 Sep 2020 23:16:23 +0000 (23:16 +0000)]
Auto merge of #75200 - ssomers:btree_valmut, r=Mark-Simulacrum

 BTreeMap: introduce marker::ValMut and reserve Mut for unique access

The mutable BTreeMap iterators (apart from `DrainFilter`) are double-ended, meaning they have to rely on a front and a back handle that each represent a reference into the tree. Reserve a type category `marker::ValMut` for them, so that we guarantee that they cannot reach operations on handles with borrow type `marker::Mut`and that these operations can assume unique access to the tree.

Including #75195, benchmarks report no genuine change:
```
benchcmp old new --threshold 5
 name                                 old ns/iter  new ns/iter  diff ns/iter   diff %  speedup
 btree::map::iter_100                 3,333        3,023                -310   -9.30%   x 1.10
 btree::map::range_unbounded_vs_iter  36,624       31,569             -5,055  -13.80%   x 1.16
```

r? @Mark-Simulacrum

3 years agoBless changed test output
Jack Huey [Fri, 4 Sep 2020 05:51:57 +0000 (01:51 -0400)]
Bless changed test output

3 years agoReview comments
Jack Huey [Sat, 15 Aug 2020 22:04:11 +0000 (18:04 -0400)]
Review comments

3 years agoMore chalk work
Jack Huey [Wed, 5 Aug 2020 02:28:59 +0000 (22:28 -0400)]
More chalk work

3 years agoUpgrade chalk to 0.21
Jack Huey [Tue, 4 Aug 2020 22:35:37 +0000 (18:35 -0400)]
Upgrade chalk to 0.21

3 years agoAuto merge of #76292 - Aaron1011:fix/proc-macro-panic-hide, r=petrochenkov
bors [Fri, 4 Sep 2020 20:58:37 +0000 (20:58 +0000)]
Auto merge of #76292 - Aaron1011:fix/proc-macro-panic-hide, r=petrochenkov

Respect `-Z proc-macro-backtrace` flag for panics inside libproc_macro

Fixes #76270

Previously, any panic occuring during a call to a libproc_macro method
(e.g. calling `Ident::new` with an invalid identifier) would always
cause an ICE message to be printed.

3 years agoAuto merge of #76315 - lcnr:map-track-caller, r=Mark-Simulacrum
bors [Fri, 4 Sep 2020 19:05:20 +0000 (19:05 +0000)]
Auto merge of #76315 - lcnr:map-track-caller, r=Mark-Simulacrum

add `#[track_caller]` to `local_def_id_to_hir_id`

Improves one of the more frequent ICE

3 years agoAuto merge of #75077 - LeSeulArtichaut:tys-kind, r=nikomatsakis
bors [Fri, 4 Sep 2020 17:07:39 +0000 (17:07 +0000)]
Auto merge of #75077 - LeSeulArtichaut:tys-kind, r=nikomatsakis

Refractor ty.kind -> ty.kind() and ty.flags -> ty.flags()

First step for the ["shared library to represent Rust types"](https://rust-lang.github.io/compiler-team/minutes/design-meeting/2020-03-12-shared-library-for-types/) work (rust-lang/wg-traits#16).

This PR makes the `TyS::kind` field private and adds a `kind()` method to access it.
As noted [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/144729-wg-traits/topic/Looking.20to.20contribute/near/205185412), this refractoring might require a MCP. I am perfectly fine with having to wait until MCP is accepted and resolving the conflicts that pop up afterwards.

r? @nikomatsakis

3 years agoty.flags -> ty.flags()
LeSeulArtichaut [Thu, 6 Aug 2020 15:49:46 +0000 (17:49 +0200)]
ty.flags -> ty.flags()

3 years ago`ty.kind` -> `ty.kind()` in rustdoc and clippy
LeSeulArtichaut [Mon, 3 Aug 2020 22:18:29 +0000 (00:18 +0200)]
`ty.kind` -> `ty.kind()` in rustdoc and clippy

3 years agoChange ty.kind to a method
LeSeulArtichaut [Sun, 2 Aug 2020 22:49:11 +0000 (00:49 +0200)]
Change ty.kind to a method

3 years agoAuto merge of #75655 - nielx:fix/haiku-llvm-libz, r=Mark-Simulacrum
bors [Fri, 4 Sep 2020 14:32:33 +0000 (14:32 +0000)]
Auto merge of #75655 - nielx:fix/haiku-llvm-libz, r=Mark-Simulacrum

Disable zlib in LLVM on Haiku

PR #72696 enabled the option LLVM_ENABLE_ZLIB for the LLVM builds. Like NetBSD and aarch64-apple-darwin (see PR #75500), the LLVM build system not explicitly linking to libz on these platforms cause issues. For Haiku, this meant the runtime loader complaining about undefined symbols..

3 years agoFix warning whe building profiler_builtins crate
Mateusz Mikuła [Mon, 24 Aug 2020 09:57:32 +0000 (11:57 +0200)]
Fix warning whe building profiler_builtins crate

3 years agoEnable profiler tests on Windows-gnu
Mateusz Mikuła [Wed, 5 Aug 2020 08:58:04 +0000 (10:58 +0200)]
Enable profiler tests on Windows-gnu

3 years agoMisc cleanup
Joshua Nelson [Sat, 29 Aug 2020 19:19:43 +0000 (15:19 -0400)]
Misc cleanup

- Preserve suffixes when displaying
- Rename test file to match `intra-link*`
- Remove unnecessary .clone()s
- Improve comments and naming
- Fix more bugs and add tests
- Escape intra-doc link example in public documentation

3 years agoAuto merge of #75207 - dylni:add-slice-check-range, r=KodrAus
bors [Fri, 4 Sep 2020 12:21:43 +0000 (12:21 +0000)]
Auto merge of #75207 - dylni:add-slice-check-range, r=KodrAus

Add `slice::check_range`

This method is useful for [`RangeBounds`] parameters. It's even been [rewritten](https://github.com/rust-lang/rust/blob/22ee68dc586440f96b76b32fbd6087507c6afdb9/src/librustc_data_structures/sorted_map.rs#L214) [many](https://github.com/rust-lang/rust/blob/22ee68dc586440f96b76b32fbd6087507c6afdb9/library/alloc/src/vec.rs#L1299) [times](https://github.com/rust-lang/rust/blob/22ee68dc586440f96b76b32fbd6087507c6afdb9/library/core/src/slice/mod.rs#L2441) in the standard library, sometimes assuming that the bounds won't be [`usize::MAX`].

For example, [`Vec::drain`] creates an empty iterator when [`usize::MAX`] is used as an inclusive end bound:

```rust
assert!(vec![1].drain(..=usize::max_value()).eq(iter::empty()));
```

If this PR is merged, I'll create another to use it for those methods.

[`RangeBounds`]: https://doc.rust-lang.org/std/ops/trait.RangeBounds.html
[`usize::MAX`]: https://doc.rust-lang.org/std/primitive.usize.html#associatedconstant.MAX
[`Vec::drain`]: https://doc.rust-lang.org/std/vec/struct.Vec.html#method.drain

3 years agoadd track_caller to `local_def_id_to_hir_id`
Bastian Kauschke [Fri, 4 Sep 2020 07:24:44 +0000 (09:24 +0200)]
add track_caller to `local_def_id_to_hir_id`

3 years agoAdd slice primitive link to vec
Ivan Tham [Fri, 4 Sep 2020 01:50:50 +0000 (09:50 +0800)]
Add slice primitive link to vec

3 years agoAuto merge of #76004 - richkadel:llvm-coverage-map-gen-6b.5, r=tmandry
bors [Fri, 4 Sep 2020 01:31:07 +0000 (01:31 +0000)]
Auto merge of #76004 - richkadel:llvm-coverage-map-gen-6b.5, r=tmandry

Tools, tests, and experimenting with MIR-derived coverage counters

Leverages the new mir_dump output file in HTML+CSS (from #76074) to visualize coverage code regions
and the MIR features that they came from (including overlapping spans).

See example below.

The `run-make-fulldeps/instrument-coverage` test has been refactored to maximize test coverage and reduce code duplication. The new tests support testing with and without `-Clink-dead-code`, so Rust coverage can be tested on MSVC (which, currently, only works with `link-dead-code` _disabled_).

New tests validate coverage region generation and coverage reports with multiple counters per function. Starting with a simple `if-else` branch tests, coverage tests for each additional syntax type can be added by simply dropping in a new Rust sample program.

Includes a basic, MIR-block-based implementation of coverage injection,
available via `-Zexperimental-coverage`. This implementation has known
flaws and omissions, but is simple enough to validate the new tools and
tests.

The existing `-Zinstrument-coverage` option currently enables
function-level coverage only, which at least appears to generate
accurate coverage reports at that level.

Experimental coverage is not accurate at this time. When branch coverage
works as intended, the `-Zexperimental-coverage` option should be
removed.

This PR replaces the bulk of PR #75828, with the remaining parts of
that PR distributed among other separate and indentpent PRs.

This PR depends on two of those other PRs: #76002, #76003 and #76074

Rust compiler MCP rust-lang/compiler-team#278

Relevant issue: #34701 - Implement support for LLVMs code coverage
instrumentation

![Screen-Recording-2020-08-21-at-2](https://user-images.githubusercontent.com/3827298/90972923-ff417880-e4d1-11ea-92bb-8713c6198f6d.gif)

r? @tmandry
FYI: @wesleywiser

3 years agoinliner: Add mir-opt tests for codegen attributes compatibility
Tomasz Miąsko [Fri, 4 Sep 2020 00:00:00 +0000 (00:00 +0000)]
inliner: Add mir-opt tests for codegen attributes compatibility

3 years agoinliner: Check for no_sanitize attribute compatibility
Tomasz Miąsko [Thu, 3 Sep 2020 00:00:00 +0000 (00:00 +0000)]
inliner: Check for no_sanitize attribute compatibility

3 years agoinliner: Check for target features compatibility
Tomasz Miąsko [Thu, 3 Sep 2020 00:00:00 +0000 (00:00 +0000)]
inliner: Check for target features compatibility

3 years agoAuto merge of #73996 - da-x:short-unique-paths, r=petrochenkov
bors [Thu, 3 Sep 2020 23:27:45 +0000 (23:27 +0000)]
Auto merge of #73996 - da-x:short-unique-paths, r=petrochenkov

diagnostics: shorten paths of unique symbols

This is a step towards implementing a fix for #50310, and continuation of the discussion in [Pre-RFC: Nicer Types In Diagnostics - compiler - Rust Internals](https://internals.rust-lang.org/t/pre-rfc-nicer-types-in-diagnostics/11139). Impressed upon me from previous discussion in #21934 that an RFC for this is not needed, and I should just come up with code.

The recent improvements to `use` suggestions that I've contributed have given rise to this implementation. Contrary to previous suggestions, it's rather simple logic, and I believe it only reduces the amount of cognitive load that a developer would need when reading type errors.

-----

If a symbol name can only be imported from one place, and as long as it was not glob-imported anywhere in the current crate, we can trim its printed path to the last component.

This has wide implications on error messages with types, for example, shortening `std::vec::Vec` to just `Vec`, as long as there is no other `Vec` importable from anywhere.

3 years agoOptimize Cursor::look_ahead
Aleksey Kladov [Thu, 3 Sep 2020 21:26:59 +0000 (23:26 +0200)]
Optimize Cursor::look_ahead

Cloning a tt is cheap, but not free (there's Arc inside).

3 years agoAuto merge of #70793 - the8472:in-place-iter-collect, r=Amanieu
bors [Thu, 3 Sep 2020 21:20:21 +0000 (21:20 +0000)]
Auto merge of #70793 - the8472:in-place-iter-collect, r=Amanieu

specialize some collection and iterator operations to run in-place

This is a rebase and update of #66383 which was closed due inactivity.

Recent rustc changes made the compile time regressions disappear, at least for webrender-wrench. Running a stage2 compile and the rustc-perf suite takes hours on the hardware I have at the moment, so I can't do much more than that.

![Screenshot_2020-04-05 rustc performance data](https://user-images.githubusercontent.com/1065730/78462657-5d60f100-76d4-11ea-8a0b-4f3962707c38.png)

In the best case of the `vec::bench_in_place_recycle` synthetic microbenchmark these optimizations can provide a 15x speedup over the regular implementation which allocates a new vec for every benchmark iteration. [Benchmark results](https://gist.github.com/the8472/6d999b2d08a2bedf3b93f12112f96e2f). In real code the speedups are tiny, but it also depends on the allocator used, a system allocator that uses a process-wide mutex will benefit more than one with thread-local pools.

## What was changed

* `SpecExtend` which covered `from_iter` and `extend` specializations was split into separate traits
* `extend` and `from_iter` now reuse the `append_elements` if passed iterators are from slices.
* A preexisting `vec.into_iter().collect::<Vec<_>>()` optimization that passed through the original vec has been generalized further to also cover cases where the original has been partially drained.
* A chain of *Vec<T> / BinaryHeap<T> / Box<[T]>* `IntoIter`s  through various iterator adapters collected into *Vec<U>* and *BinaryHeap<U>* will be performed in place as long as `T` and `U` have the same alignment and size and aren't ZSTs.
* To enable above specialization the unsafe, unstable `SourceIter` and `InPlaceIterable` traits have been added. The first allows reaching through the iterator pipeline to grab a pointer to the source memory. The latter is a marker that promises that the read pointer will advance as fast or faster than the write pointer and thus in-place operation is possible in the first place.
* `vec::IntoIter` implements `TrustedRandomAccess` for `T: Copy` to allow in-place collection when there is a `Zip` adapter in the iterator. TRA had to be made an unstable public trait to support this.

## In-place collectible adapters

* `Map`
* `MapWhile`
* `Filter`
* `FilterMap`
* `Fuse`
* `Skip`
* `SkipWhile`
* `Take`
* `TakeWhile`
* `Enumerate`
* `Zip` (left hand side only, `Copy` types only)
* `Peek`
* `Scan`
* `Inspect`

## Concerns

`vec.into_iter().filter(|_| false).collect()` will no longer return a vec with 0 capacity, instead it will return its original allocation. This avoids the cost of doing any allocation or deallocation but could lead to large allocations living longer than expected.
If that's not acceptable some resizing policy at the end of the attempted in-place collect would be necessary, which in the worst case could result in one more memcopy than the non-specialized case.

## Possible followup work

* split liballoc/vec.rs to remove `ignore-tidy-filelength`
* try to get trivial chains such as `vec.into_iter().skip(1).collect::<Vec<)>>()` to compile to a `memmove` (currently compiles to a pile of SIMD, see #69187 )
* improve up the traits so they can be reused by other crates, e.g. itertools. I think currently they're only good enough for internal use
* allow iterators sourced from a `HashSet` to be in-place collected into a `Vec`

3 years agofix debug assertion
The8472 [Thu, 3 Sep 2020 20:15:47 +0000 (22:15 +0200)]
fix debug assertion

The InPlaceIterable debug assert checks that the write pointer
did not advance beyond the read pointer. But TrustedRandomAccess
never advances the read pointer, thus triggering the assert.
Skip the assert if the source pointer did not change during iteration.

3 years agoAdd test for doc alias on associated const in trait impls
Guillaume Gomez [Mon, 24 Aug 2020 18:20:31 +0000 (20:20 +0200)]
Add test for doc alias on associated const in trait impls

3 years agoAdd check for doc alias on associated const in trait impls
Guillaume Gomez [Mon, 24 Aug 2020 18:20:03 +0000 (20:20 +0200)]
Add check for doc alias on associated const in trait impls

3 years agoCheck test/example/benchmark on x.py check
Mark Rousskov [Wed, 2 Sep 2020 20:41:36 +0000 (16:41 -0400)]
Check test/example/benchmark on x.py check

Often when modifying compiler code you'll miss that you've changed an API used
by unit tests, since x.py check didn't previously catch that.

It's also useful to have this for editing with rust-analyzer and similar tooling
where editing tests previously didn't notify you of errors in test files.

3 years agoAuto merge of #73819 - euclio:rustdoc-summaries, r=jyn514,GuillaumeGomez
bors [Thu, 3 Sep 2020 19:07:38 +0000 (19:07 +0000)]
Auto merge of #73819 - euclio:rustdoc-summaries, r=jyn514,GuillaumeGomez

rustdoc: do not use plain summary for trait impls

Fixes #38386.
Fixes #48332.
Fixes #49430.
Fixes #62741.
Fixes #73474.

Unfortunately this is not quite ready to go because the newly-working links trigger a bunch of linkcheck failures. The failures are tough to fix because the links are resolved relative to the implementor, which could be anywhere in the module hierarchy.

(In the current docs, these links end up rendering as uninterpreted markdown syntax, so I don't think these failures are any worse than the status quo. It might be acceptable to just add them to the linkchecker whitelist.)

Ideally this could be fixed with intra-doc links ~~but it isn't working for me: I am currently investigating if it's possible to solve it this way.~~ Opened #73829.

EDIT: This is now ready!

3 years agoimprove comments and naming
The8472 [Wed, 2 Sep 2020 19:40:19 +0000 (21:40 +0200)]
improve comments and naming

3 years agoadd explanation to specialization marker
The8472 [Sun, 30 Aug 2020 00:15:45 +0000 (02:15 +0200)]
add explanation to specialization marker

3 years agoremove separate no-drop code path since it resulted in more LLVM IR
The8472 [Wed, 26 Aug 2020 21:32:09 +0000 (23:32 +0200)]
remove separate no-drop code path since it resulted in more LLVM IR

3 years agoremove empty Vec extend optimization
The8472 [Wed, 26 Aug 2020 21:24:34 +0000 (23:24 +0200)]
remove empty Vec extend optimization

The optimization meant that every extend code path had to emit llvm
IR for from_iter and extend spec_extend, which likely impacts
compile times while only improving a few edge-cases

3 years agoplease tidy
The8472 [Fri, 21 Aug 2020 21:56:23 +0000 (23:56 +0200)]
please tidy

3 years agoget things to work under min_specialization by leaning more heavily on #[rustc_unsafe...
The8472 [Fri, 21 Aug 2020 21:53:13 +0000 (23:53 +0200)]
get things to work under min_specialization by leaning more heavily on #[rustc_unsafe_specialization_marker]

3 years agoavoid applying in-place collect specialization in type-length test
The8472 [Sun, 24 May 2020 01:23:15 +0000 (03:23 +0200)]
avoid applying in-place collect specialization in type-length test

the test was sized to match external iteration only, since
vec's in-place collect now uses internal iteration we collect into
a different type now.
Note that any other try-fold based operation such as count() would also
have exceeded the type length limit for that iterator.

3 years agofix benchmark compile errors
The8472 [Wed, 20 May 2020 23:34:05 +0000 (01:34 +0200)]
fix benchmark compile errors

3 years agoapply required min_specialization attributes
The8472 [Mon, 18 May 2020 22:44:16 +0000 (00:44 +0200)]
apply required min_specialization attributes

3 years agosupport in-place collect for MapWhile adapters
The8472 [Sat, 4 Apr 2020 16:34:18 +0000 (18:34 +0200)]
support in-place collect for MapWhile adapters

3 years agopacify tidy
The8472 [Sun, 2 Feb 2020 19:24:40 +0000 (20:24 +0100)]
pacify tidy

3 years agogeneralize in-place collect to types of same size and alignment
The8472 [Tue, 28 Jan 2020 14:14:55 +0000 (15:14 +0100)]
generalize in-place collect to types of same size and alignment

3 years agoincrease comment verbosity
The8472 [Sun, 26 Jan 2020 19:52:59 +0000 (20:52 +0100)]
increase comment verbosity

3 years agowork around compiler overhead around lambdas in generics by extracting them into...
The8472 [Sun, 26 Jan 2020 19:51:57 +0000 (20:51 +0100)]
work around compiler overhead around lambdas in generics by extracting them into free functions

3 years agoextract IntoIter drop/forget used by specialization into separate methods
The8472 [Sun, 26 Jan 2020 19:50:05 +0000 (20:50 +0100)]
extract IntoIter drop/forget used by specialization into separate methods

3 years agoadd benchmark to cover in-place extend
The8472 [Sat, 25 Jan 2020 19:08:46 +0000 (20:08 +0100)]
add benchmark to cover in-place extend

3 years agoremove redundant cast
The8472 [Sat, 25 Jan 2020 16:58:34 +0000 (17:58 +0100)]
remove redundant cast

3 years agotest drops during in-place iteration
The8472 [Sat, 25 Jan 2020 16:55:47 +0000 (17:55 +0100)]
test drops during in-place iteration

3 years agomove unsafety into method, not relevant to caller
The8472 [Sat, 25 Jan 2020 14:02:13 +0000 (15:02 +0100)]
move unsafety into method, not relevant to caller

3 years agoreplace unsafe ptr::write with deref-write, benchmarks show no difference
The8472 [Sat, 25 Jan 2020 14:01:39 +0000 (15:01 +0100)]
replace unsafe ptr::write with deref-write, benchmarks show no difference

3 years agopacify tidy
The8472 [Wed, 15 Jul 2020 18:53:03 +0000 (20:53 +0200)]
pacify tidy

3 years agoreplace drop flag with ManuallyDrop
The8472 [Sat, 18 Jan 2020 15:13:28 +0000 (16:13 +0100)]
replace drop flag with ManuallyDrop

3 years agomark as_inner as unsafe and update comments
The8472 [Sat, 18 Jan 2020 15:03:58 +0000 (16:03 +0100)]
mark as_inner as unsafe and update comments

3 years agoavoid exposing that binary heap's IntoIter is backed by vec::IntoIter, use a private...
The8472 [Fri, 20 Dec 2019 19:28:10 +0000 (20:28 +0100)]
avoid exposing that binary heap's IntoIter is backed by vec::IntoIter, use a private trait instead

3 years agofix: bench didn't black_box its results
The8472 [Sat, 30 Nov 2019 18:40:28 +0000 (19:40 +0100)]
fix: bench didn't black_box its results

3 years agofix build issue due to stabilized feature
The8472 [Sat, 30 Nov 2019 14:35:18 +0000 (15:35 +0100)]
fix build issue due to stabilized feature

3 years agoimpl TrustedRandomAccess for vec::IntoIter
The8472 [Fri, 29 Nov 2019 00:11:14 +0000 (01:11 +0100)]
impl TrustedRandomAccess for vec::IntoIter

3 years agobench larger allocations
The8472 [Wed, 27 Nov 2019 21:19:15 +0000 (22:19 +0100)]
bench larger allocations

3 years agoinclude in-place .zip() in test
The8472 [Wed, 27 Nov 2019 21:19:06 +0000 (22:19 +0100)]
include in-place .zip() in test

3 years agoremove unecessary feature flag
The8472 [Mon, 24 Aug 2020 20:09:44 +0000 (22:09 +0200)]
remove unecessary feature flag

# Conflicts:
# library/alloc/src/lib.rs

3 years agomake tidy happy
The8472 [Sat, 23 Nov 2019 18:34:26 +0000 (19:34 +0100)]
make tidy happy

3 years agosupport in-place iteration for most adapters
The8472 [Sat, 23 Nov 2019 17:59:18 +0000 (18:59 +0100)]
support in-place iteration for most adapters

`Take` is not included since users probably call it with small constants
and it doesn't make sense to hold onto huge allocations in that case

3 years agomove free-standing method into trait impl
The8472 [Sat, 23 Nov 2019 17:30:32 +0000 (18:30 +0100)]
move free-standing method into trait impl

3 years agoadd in-place iteration for Zip
The8472 [Sat, 23 Nov 2019 17:29:47 +0000 (18:29 +0100)]
add in-place iteration for Zip

this picks the left hand side as source since it might be more natural to
consume that as IntoIter source

3 years agobench in-place zip
The8472 [Sat, 23 Nov 2019 17:26:52 +0000 (18:26 +0100)]
bench in-place zip

3 years agoadditional specializations tests
The8472 [Sat, 23 Nov 2019 13:34:58 +0000 (14:34 +0100)]
additional specializations tests

3 years agofix some in-place-collect edge-cases
The8472 [Sat, 23 Nov 2019 13:32:20 +0000 (14:32 +0100)]
fix some in-place-collect edge-cases

- it's an allocation optimization, so don't attempt to do it on ZSTs
- drop the tail of partially exhausted iters

3 years agoremove redundant code
The8472 [Sat, 23 Nov 2019 13:30:10 +0000 (14:30 +0100)]
remove redundant code

3 years agoimprove comments
The8472 [Thu, 21 Nov 2019 12:44:28 +0000 (13:44 +0100)]
improve comments

3 years agospecialize creating a Vec from a slice iterator where T: Copy
The8472 [Thu, 21 Nov 2019 12:43:53 +0000 (13:43 +0100)]
specialize creating a Vec from a slice iterator where T: Copy

this was already implemented for Extend but not for FromIterator

3 years agorestore SpecFrom<T, TrustedLen<Item=T>> specialization by nesting
The8472 [Thu, 21 Nov 2019 12:40:49 +0000 (13:40 +0100)]
restore SpecFrom<T, TrustedLen<Item=T>> specialization by nesting
specializations

3 years agouse From specializations on extend if extended Vec is empty
The8472 [Thu, 21 Nov 2019 12:24:48 +0000 (13:24 +0100)]
use From specializations on extend if extended Vec is empty

this enables in-place iteration and allocation reuse in additional cases