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
```
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.
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.
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..
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:
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
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.
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.
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.
`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`
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.
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.
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
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.
Aaron Hill [Thu, 3 Sep 2020 16:11:18 +0000 (12:11 -0400)]
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.
Rich Kadel [Thu, 27 Aug 2020 21:13:04 +0000 (14:13 -0700)]
Tools, tests, and experimenting with MIR-derived coverage counters
Adds a new mir_dump output file in HTML/CSS to visualize code regions
and the MIR features that they came from (including overlapping spans).
See example below:
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 three of those other PRs: #76000, #76002, and
Rust compiler MCP rust-lang/compiler-team#278
Relevant issue: #34701 - Implement support for LLVMs code coverage
instrumentation
Dan Aloni [Thu, 3 Sep 2020 06:30:51 +0000 (09:30 +0300)]
rustc_driver: have TrimmedDefPaths::GoodPath only for rustc
`run_compiler` is used by clippy and other tools, which should not have
the trimmed paths feature enabled by default, until we see it works well
for them.
Would also be nice to rename `TimePassesCallbacks` however it's a
submodule change.
Auto merge of #76235 - jyn514:std-intra-links, r=poliorcetics
Convert many files to intra-doc links
Helps with https://github.com/rust-lang/rust/issues/75080
r? @poliorcetics
I recommend reviewing one commit at a time, but the diff is small enough you can do it all at once if you like :)
Auto merge of #75971 - Amjad50:libstd-deny-unsafe_op_in_unsafe_fn, r=Mark-Simulacrum
Applied `#![deny(unsafe_op_in_unsafe_fn)]` in library/std/src/wasi
partial fix for #73904
There are still more that was not applied in [mod.rs]( https://github.com/rust-lang/rust/blob/38fab2ea92a48980219989817201bf2094ae826a/library/std/src/sys/wasi/mod.rs) and that is due to its using files from `../unsupported`
like:
```
#[path = "../unsupported/cmath.rs"]
pub mod cmath;
```
Rollup merge of #76255 - ehuss:update-books, r=ehuss
Update books
## reference
4 commits in 1b6c4b0afab97c0230433466c97167bbbe8445f6..25391dba46262f882fa846beefaff54a966a8fa5
2020-08-18 17:04:28 -0700 to 2020-09-02 07:22:55 -0700
- clarify when reading uninititalized memory is allowed (rust-lang-nursery/reference#852)
- Update patterns chapter, add rest patterns. (rust-lang-nursery/reference#876)
- Improve Type-Coersion Documentation (rust-lang-nursery/reference#843)
- Added variable back into example. (rust-lang-nursery/reference#880)
## book
3 commits in c0a6a61b8205da14ac955425f74258ffd8ee065d..e5ed97128302d5fa45dbac0e64426bc7649a558c
2020-08-14 14:21:49 -0500 to 2020-08-31 12:53:40 -0500
- Fix type mismatch in listing 10-5 (rust-lang/book#2441)
- Update ppendix-06-translation.md (rust-lang/book#2437)
- Correct no-listing-10-result-in-tests: Take tests module out of the main function (rust-lang/book#2430)
## rust-by-example
3 commits in 80a10e22140e28392b99d24ed02f4c6d8cb770a0..19f0a0372af497b34369cf182d9d16156cab2969
2020-08-08 09:56:46 -0300 to 2020-08-26 09:38:48 -0300
- prefer `length` over `size` when talking about number of elements vs. bytesize (rust-lang/rust-by-example#1372)
- Split out variable shadowing into a separate example (rust-lang/rust-by-example#1370)
- Update extern crate related sections (rust-lang/rust-by-example#1369)
Rollup merge of #76245 - tmiasko:inline-generators, r=ecstatic-morse
inliner: Avoid query cycles when optimizing generators
The HIR Id trick is insufficient to prevent query cycles when optimizing
generators, since merely requesting a layout of a generator also
computes its `optimized_mir`.
Make no attempts to inline functions into generators within the same
crate to avoid query cycles.
Rollup merge of #76243 - ama0:patch-1, r=jonas-schievink
Fix typos in vec try_reserve(_exact) docs
`try_reserve` and `try_reserve_exact` docs refer to calling `reserve` and `reserve_exact`.
`try_reserve_exact` example uses `try_reserve` method instead of `try_reserve_exact`.
Rollup merge of #76242 - RalfJung:read-fixme, r=Dylan-DPC
Read: adjust a FIXME reference
There's already another reference to https://github.com/rust-lang/rust/issues/42788 for basically the same problem, so lets reuse it here:
https://github.com/rust-lang/rust/blob/5e208efaa850efaa97495e81c49cf0f5767e8f49/library/std/src/io/mod.rs#L369-L376
Rollup merge of #76238 - denisvasilik:intra-doc-links-core-iterator, r=jyn514
Move to intra-doc links for library/core/src/iter/traits/iterator.rs
Helps with #75080.
@jyn514 We're almost finished with this issue. Thanks for mentoring. If you have other topics to work on just let me know, I will be around in Discord.
Rollup merge of #76120 - LukasKalbertodt:add-as-slice-method-to-array, r=Mark-Simulacrum
Add `[T; N]::as_[mut_]slice`
Part of me trying to populate arrays with a couple of basic useful methods, like slices already have. The ability to add methods to arrays were added in #75212. Tracking issue: #76118
Rollup merge of #75150 - nanpuyue:deprecate_to_ipv6_compatible, r=LukasKalbertodt
Add a note for Ipv4Addr::to_ipv6_compatible
Previous discussion: #75019
> I think adding a comment saying "This isn't typically the method you want; these addresses don't typically function on modern systems. Use `to_ipv6_mapped` instead." would be a good first step, whether this method gets marked as deprecated or not.
_Originally posted by @joshtriplett in https://github.com/rust-lang/rust/pull/75150#issuecomment-680267745_