Commit Graph

2048 Commits

Author SHA1 Message Date
Yuki Okushi
c1ee9a3a03
Rollup merge of #87183 - RalfJung:option-doctest, r=jyn514
fix typo in compile_fail doctest

Fixes a typo introduced by https://github.com/rust-lang/rust/pull/86211. For some reason this typo makes Miri go all crazy when running libcore doctests (https://github.com/rust-lang/miri/issues/1852). Kudos to ``@hyd-dev`` for noticing the typo.

Cc ``@tlyu`` ``@joshtriplett``
2021-07-18 14:21:58 +09:00
Yuki Okushi
07faa2e32c
Rollup merge of #87170 - xFrednet:clippy-5393-add-diagnostic-items, r=Manishearth,oli-obk
Add diagnostic items for Clippy

This adds a bunch of diagnostic items to `std`/`core`/`alloc` functions, structs and traits used in Clippy. The actual refactorings in Clippy to use these items will be done in a different PR in Clippy after the next sync.

This PR doesn't include all paths Clippy uses, I've only gone through the first 85 lines of Clippy's [`paths.rs`](ecf85f4bdc/clippy_utils/src/paths.rs) (after rust-lang/rust-clippy#7466) to get some feedback early on. I've also decided against adding diagnostic items to methods, as it would be nicer and more scalable to access them in a nicer fashion, like adding a `is_diagnostic_assoc_item(did, sym::Iterator, sym::map)` function or something similar (Suggested by `@camsteffen` [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/147480-t-compiler.2Fwg-diagnostics/topic/Diagnostic.20Item.20Naming.20Convention.3F/near/225024603))

There seems to be some different naming conventions when it comes to diagnostic items, some use UpperCamelCase (`BinaryHeap`) and some snake_case (`hashmap_type`). This PR uses UpperCamelCase for structs and traits and snake_case with the module name as a prefix for functions. Any feedback on is this welcome.

cc: rust-lang/rust-clippy#5393

r? `@Manishearth`
2021-07-18 14:21:57 +09:00
bors
f502bd3abd Auto merge of #86761 - Alexhuszagh:master, r=estebank
Update Rust Float-Parsing Algorithms to use the Eisel-Lemire algorithm.

# Summary

Rust, although it implements a correct float parser, has major performance issues in float parsing. Even for common floats, the performance can be 3-10x [slower](https://arxiv.org/pdf/2101.11408.pdf) than external libraries such as [lexical](https://github.com/Alexhuszagh/rust-lexical) and [fast-float-rust](https://github.com/aldanor/fast-float-rust).

Recently, major advances in float-parsing algorithms have been developed by Daniel Lemire, along with others, and implement a fast, performant, and correct float parser, with speeds up to 1200 MiB/s on Apple's M1 architecture for the [canada](0e2b5d163d/data/canada.txt) dataset, 10x faster than Rust's 130 MiB/s.

In addition, [edge-cases](https://github.com/rust-lang/rust/issues/85234) in Rust's [dec2flt](868c702d0c/library/core/src/num/dec2flt) algorithm can lead to over a 1600x slowdown relative to efficient algorithms. This is due to the use of Clinger's correct, but slow [AlgorithmM and Bellepheron](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.45.4152&rep=rep1&type=pdf), which have been improved by faster big-integer algorithms and the Eisel-Lemire algorithm, respectively.

Finally, this algorithm provides substantial improvements in the number of floats the Rust core library can parse. Denormal floats with a large number of digits cannot be parsed, due to use of the `Big32x40`, which simply does not have enough digits to round a float correctly. Using a custom decimal class, with much simpler logic, we can parse all valid decimal strings of any digit count.

```rust
// Issue in Rust's dec2fly.
"2.47032822920623272088284396434110686182e-324".parse::<f64>();   // Err(ParseFloatError { kind: Invalid })
```

# Solution

This pull request implements the Eisel-Lemire algorithm, modified from [fast-float-rust](https://github.com/aldanor/fast-float-rust) (which is licensed under Apache 2.0/MIT), along with numerous modifications to make it more amenable to inclusion in the Rust core library. The following describes both features in fast-float-rust and improvements in fast-float-rust for inclusion in core.

**Documentation**

Extensive documentation has been added to ensure the code base may be maintained by others, which explains the algorithms as well as various associated constants and routines. For example, two seemingly magical constants include documentation to describe how they were derived as follows:

```rust
    // Round-to-even only happens for negative values of q
    // when q ≥ −4 in the 64-bit case and when q ≥ −17 in
    // the 32-bitcase.
    //
    // When q ≥ 0,we have that 5^q ≤ 2m+1. In the 64-bit case,we
    // have 5^q ≤ 2m+1 ≤ 2^54 or q ≤ 23. In the 32-bit case,we have
    // 5^q ≤ 2m+1 ≤ 2^25 or q ≤ 10.
    //
    // When q < 0, we have w ≥ (2m+1)×5^−q. We must have that w < 2^64
    // so (2m+1)×5^−q < 2^64. We have that 2m+1 > 2^53 (64-bit case)
    // or 2m+1 > 2^24 (32-bit case). Hence,we must have 2^53×5^−q < 2^64
    // (64-bit) and 2^24×5^−q < 2^64 (32-bit). Hence we have 5^−q < 2^11
    // or q ≥ −4 (64-bit case) and 5^−q < 2^40 or q ≥ −17 (32-bitcase).
    //
    // Thus we have that we only need to round ties to even when
    // we have that q ∈ [−4,23](in the 64-bit case) or q∈[−17,10]
    // (in the 32-bit case). In both cases,the power of five(5^|q|)
    // fits in a 64-bit word.
    const MIN_EXPONENT_ROUND_TO_EVEN: i32;
    const MAX_EXPONENT_ROUND_TO_EVEN: i32;
```

This ensures maintainability of the code base.

**Improvements for Disguised Fast-Path Cases**

The fast path in float parsing algorithms attempts to use native, machine floats to represent both the significant digits and the exponent, which is only possible if both can be exactly represented without rounding. In practice, this means that the significant digits must be 53-bits or less and the then exponent must be in the range `[-22, 22]` (for an f64). This is similar to the existing dec2flt implementation.

However, disguised fast-path cases exist, where there are few significant digits and an exponent above the valid range, such as `1.23e25`. In this case, powers-of-10 may be shifted from the exponent to the significant digits, discussed at length in https://github.com/rust-lang/rust/issues/85198.

**Digit Parsing Improvements**

Typically, integers are parsed from string 1-at-a-time, requiring unnecessary multiplications which can slow down parsing. An approach to parse 8 digits at a time using only 3 multiplications is described in length [here](https://johnnylee-sde.github.io/Fast-numeric-string-to-int/). This leads to significant performance improvements, and is implemented for both big and little-endian systems.

**Unsafe Changes**

Relative to fast-float-rust, this library makes less use of unsafe functionality and clearly documents it. This includes the refactoring and documentation of numerous unsafe methods undesirably marked as safe. The original code would look something like this, which is deceptively marked as safe for unsafe functionality.

```rust
impl AsciiStr {
    #[inline]
    pub fn step_by(&mut self, n: usize) -> &mut Self {
        unsafe { self.ptr = self.ptr.add(n) };
        self
    }
}

...

#[inline]
fn parse_scientific(s: &mut AsciiStr<'_>) -> i64 {
    // the first character is 'e'/'E' and scientific mode is enabled
    let start = *s;
    s.step();
    ...
}
```

The new code clearly documents safety concerns, and does not mark unsafe functionality as safe, leading to better safety guarantees.

```rust
impl AsciiStr {
    /// Advance the view by n, advancing it in-place to (n..).
    pub unsafe fn step_by(&mut self, n: usize) -> &mut Self {
        // SAFETY: same as step_by, safe as long n is less than the buffer length
        self.ptr = unsafe { self.ptr.add(n) };
        self
    }
}

...

/// Parse the scientific notation component of a float.
fn parse_scientific(s: &mut AsciiStr<'_>) -> i64 {
    let start = *s;
    // SAFETY: the first character is 'e'/'E' and scientific mode is enabled
    unsafe {
        s.step();
    }
    ...
}
```

This allows us to trivially demonstrate the new implementation of dec2flt is safe.

**Inline Annotations Have Been Removed**

In the previous implementation of dec2flt, inline annotations exist practically nowhere in the entire module. Therefore, these annotations have been removed, which mostly does not impact [performance](https://github.com/aldanor/fast-float-rust/issues/15#issuecomment-864485157).

**Fixed Correctness Tests**

Numerous compile errors in `src/etc/test-float-parse` were present, due to deprecation of `time.clock()`, as well as the crate dependencies with `rand`. The tests have therefore been reworked as a [crate](https://github.com/Alexhuszagh/rust/tree/master/src/etc/test-float-parse), and any errors in `runtests.py` have been patched.

**Undefined Behavior**

An implementation of `check_len` which relied on undefined behavior (in fast-float-rust) has been refactored, to ensure that the behavior is well-defined. The original code is as follows:

```rust
    #[inline]
    pub fn check_len(&self, n: usize) -> bool {
        unsafe { self.ptr.add(n) <= self.end }
    }
```

And the new implementation is as follows:

```rust
    /// Check if the slice at least `n` length.
    fn check_len(&self, n: usize) -> bool {
        n <= self.as_ref().len()
    }
```

Note that this has since been fixed in [fast-float-rust](https://github.com/aldanor/fast-float-rust/pull/29).

**Inferring Binary Exponents**

Rather than explicitly store binary exponents, this new implementation infers them from the decimal exponent, reducing the amount of static storage required. This removes the requirement to store [611 i16s](868c702d0c/library/core/src/num/dec2flt/table.rs (L8)).

# Code Size

The code size, for all optimizations, does not considerably change relative to before for stripped builds, however it is **significantly** smaller prior to stripping the resulting binaries. These binary sizes were calculated on x86_64-unknown-linux-gnu.

**new**

Using rustc version 1.55.0-dev.

opt-level|size|size(stripped)
|:-:|:-:|:-:|
0|400k|300K
1|396k|292K
2|392k|292K
3|392k|296K
s|396k|292K
z|396k|292K

**old**

Using rustc version 1.53.0-nightly.

opt-level|size|size(stripped)
|:-:|:-:|:-:|
0|3.2M|304K
1|3.2M|292K
2|3.1M|284K
3|3.1M|284K
s|3.1M|284K
z|3.1M|284K

# Correctness

The dec2flt implementation passes all of Rust's unittests and comprehensive float parsing tests, along with numerous other tests such as Nigel Toa's comprehensive float [tests](https://github.com/nigeltao/parse-number-fxx-test-data) and Hrvoje Abraham  [strtod_tests](https://github.com/ahrvoje/numerics/blob/master/strtod/strtod_tests.toml). Therefore, it is unlikely that this algorithm will incorrectly round parsed floats.

# Issues Addressed

This will fix and close the following issues:

- resolves #85198
- resolves #85214
- resolves #85234
- fixes #31407
- fixes #31109
- fixes #53015
- resolves #68396
- closes https://github.com/aldanor/fast-float-rust/issues/15
2021-07-17 12:56:22 +00:00
Alex Huszagh
8752b40369 Changed dec2flt to use the Eisel-Lemire algorithm.
Implementation is based off fast-float-rust, with a few notable changes.

- Some unsafe methods have been removed.
- Safe methods with inherently unsafe functionality have been removed.
- All unsafe functionality is documented and provably safe.
- Extensive documentation has been added for simpler maintenance.
- Inline annotations on internal routines has been removed.
- Fixed Python errors in src/etc/test-float-parse/runtests.py.
- Updated test-float-parse to be a library, to avoid missing rand dependency.
- Added regression tests for #31109 and #31407 in core tests.
- Added regression tests for #31109 and #31407 in ui tests.
- Use the existing slice primitive to simplify shared dec2flt methods
- Remove Miri ignores from dec2flt, due to faster parsing times.

- resolves #85198
- resolves #85214
- resolves #85234
- fixes #31407
- fixes #31109
- fixes #53015
- resolves #68396
- closes https://github.com/aldanor/fast-float-rust/issues/15
2021-07-17 00:30:34 -05:00
bors
0cd12d649e Auto merge of #87195 - yaahc:move-assert_matches-again, r=oli-obk
rename assert_matches module

Fixes nightly breakage introduced in https://github.com/rust-lang/rust/pull/86947
2021-07-17 00:35:36 +00:00
Jane Lusby
d0e8de68c4 i sweat to god 2021-07-16 13:25:11 -07:00
Jane Lusby
085d52c588 pls this time 2021-07-16 12:16:39 -07:00
The8472
8dd903cc77 implement ConstSizeIntoIterator for &[T;N] in addition to [T;N]
Due to #20400 the corresponding TrustedLen impls need a helper trait
instead of directly adding `Item = &[T;N]` bounds.
Since TrustedLen is a public trait this in turn means
the helper trait needs to be public. Since it's just a workaround
for a compiler deficit it's marked hidden, unstable and unsafe.
2021-07-16 20:38:42 +02:00
Guillaume Gomez
7c5cabe30f
Rollup merge of #87174 - inquisitivecrystal:array-map, r=kennytm
Stabilize `[T; N]::map()`

This stabilizes the `[T; N]::map()` function, gated by the `array_map` feature. The FCP has [already completed.](https://github.com/rust-lang/rust/issues/75243#issuecomment-878448138)

Closes #75243.
2021-07-16 19:54:04 +02:00
The8472
18a034f97e rename specializing trait to ConstSizeIntoIterator 2021-07-16 19:17:30 +02:00
oxalica
774a79e3fd
Mark Option::insert as must_use 2021-07-17 00:19:44 +08:00
Jane Lusby
93b7aee2da rename assert_matches module 2021-07-16 09:18:14 -07:00
Ralf Jung
0d3d6f05f1 fix typo in compile_fail doctest 2021-07-16 10:31:56 +02:00
Guillaume Gomez
36de8778fc
Rollup merge of #87138 - dhwthompson:fix-range-invariant, r=JohnTitor
Correct invariant documentation for `steps_between`

Given that the previous example involves stepping forward from A to B, the equivalent example on this line would make most sense as stepping backward from B to A.

I should probably add a caveat here that I’m fairly new to Rust, and this is my first contribution to this repo, so it’s very possible that I’ve misunderstood how this is supposed to work (either on a technical level or a social one). If this is the case, please do let me know.
2021-07-16 10:08:06 +02:00
inquisitivecrystal
7fc4fc747c Stabilize [T; N]::map() 2021-07-15 16:27:08 -07:00
xFrednet
d38f2b0cc1 Added diagnostic items to structs and traits for Clippy 2021-07-15 23:57:02 +02:00
xFrednet
1a900042ab Added diagnostic items to functions for Clippy 2021-07-15 23:47:03 +02:00
The8472
bd1c39dc6c implement TrustedLen for Flatten/FlatMap if the U: IntoIterator == [T; N]
This only works if arrays are passed directly instead of array iterators
because we need to be sure that they have not been advanced before
Flatten does its size calculation.
2021-07-15 22:59:30 +02:00
Chayim Refael Friedman
f10da9f50a Allow leading pipe in matches!() patterns.
This is allowed in `match` statement, and stated in https://internals.rust-lang.org/t/leading-pipe-in-core-matches/14699/2 that it should be allowed in these macros too.
2021-07-15 22:05:45 +03:00
Yuki Okushi
dc464f20a1
Rollup merge of #87127 - poliorcetics:ptr-rotate-safety, r=scottmcm
Add safety comments in private core::slice::rotate::ptr_rotate function

Helps with #66219.

```@rustbot``` label C-cleanup T-compiler T-libs
2021-07-15 21:19:19 +09:00
Yuki Okushi
a5acb7b4ba
Rollup merge of #86947 - m-ou-se:assert-matches-to-submodule, r=yaahc
Move assert_matches to an inner module

Fixes #82913
2021-07-15 21:19:16 +09:00
Hans Kratz
a3fb1d6188 Make wrapping_neg() use wrapping_sub(), #[inline(always)]
This is a follow-up change to the fix for #75598. It simplifies the implementation of wrapping_neg() for all integer types by just calling 0.wrapping_sub(self) and always inlines it. This leads to much less assembly code being emitted for opt-level≤1.
2021-07-15 09:58:35 +02:00
bors
2f391da2e6 Auto merge of #86765 - cuviper:fuse-less-specialized, r=joshtriplett
Make the specialized Fuse still deal with None

Fixes #85863 by removing the assumption that we'll never see a cleared iterator in the `I: FusedIterator` specialization. Now all `Fuse` methods check for the possibility that `self.iter` is `None`, and the specialization only avoids _setting_ that to `None` in `&mut self` methods.
2021-07-14 21:17:52 +00:00
David Thompson
e753f30543 Correct invariant documentation for steps_between
Given that the previous example involves stepping forward from A to B,
the equivalent example on this line would make most sense as stepping
backward from B to A.
2021-07-14 13:48:18 -07:00
Guillaume Gomez
4d141f5e4c
Rollup merge of #87027 - petrochenkov:builderhelp, r=oli-obk
expand: Support helper attributes for built-in derive macros

This is needed for https://github.com/rust-lang/rust/pull/86735 (derive macro `Default` should have a helper attribute `default`).

With this PR we can specify helper attributes for built-in derives using syntax `#[rustc_builtin_macro(MacroName, attributes(attr1, attr2, ...))]` which mirrors equivalent syntax for proc macros `#[proc_macro_derive(MacroName, attributes(attr1, attr2, ...))]`.
Otherwise expansion infra was already ready for this.
The attribute parsing code is shared between proc macro derives and built-in macros (`fn parse_macro_name_and_helper_attrs`).
2021-07-14 19:53:35 +02:00
Alexis Bourget
4541aa971f Add safety comments in private core::slice::rotate::ptr_rotate function 2021-07-14 15:31:12 +02:00
Matthias Geier
46abc12598 DOC: Add missing arguments to hypothetical code for step_by() 2021-07-14 08:48:54 +02:00
bors
a08f25a7ef Auto merge of #86211 - tlyu:option-result-overviews, r=joshtriplett
create method overview docs for core::option and core::result

The `Option` and `Result` types have large lists of methods. They each could use an overview page of methods grouped by category. These proposed overviews include "truth tables" for the underappreciated boolean operators/combinators of these types. The methods are already somewhat categorized in the source, but some logical groupings are broken up by the necessities of putting related methods in different `impl` blocks, for example.

This is based on #86209, but those are small changes and unlikely to conflict.
2021-07-14 05:10:57 +00:00
Vadim Petrochenkov
6c9ea1e8a9 expand: Support helper attributes for built-in derive macros 2021-07-13 21:59:22 +03:00
Yuki Okushi
b507cd1745
Rollup merge of #86344 - est31:maybe-uninit-extra, r=RalfJung
Split MaybeUninit::write into new feature gate and stabilize it

This splits off the `MaybeUninit::write` function from the `maybe_uninit_extra` feature gate into a new `maybe_uninit_write` feature gate and stabilizes it.

Earlier work to improve the documentation of the write function: #86220

Tracking issue: #63567
2021-07-13 08:54:27 +09:00
est31
848a621591 Use the write function in some more places 2021-07-12 20:32:23 +02:00
Alexis Bourget
101a146db9 Fix #85462 by adding a marker flag
This will not affect ABI since the other variant of the enum is bigger.
It may break some code, but that would be very strange: usually people
don't continue after the first `Done` (or `None` for a normal iterator).
2021-07-11 17:45:12 +02:00
phlopsi
3e82dca65c Optimize fmt::PadAdapter::wrap 2021-07-11 08:06:29 +02:00
Jacob Pratt
14633a0a27
Fix tracking issue for bool_to_option 2021-07-10 18:43:52 -04:00
bors
ee86f96ba1 Auto merge of #85828 - scottmcm:raw-eq, r=oli-obk
Stop generating `alloca`s & `memcmp` for simple short array equality

Example:
```rust
pub fn demo(x: [u16; 6], y: [u16; 6]) -> bool { x == y }
```

Before:
```llvm
define zeroext i1 `@_ZN10playground4demo17h48537f7eac23948fE(i96` %0, i96 %1) unnamed_addr #0 {
start:
  %y = alloca [6 x i16], align 8
  %x = alloca [6 x i16], align 8
  %.0..sroa_cast = bitcast [6 x i16]* %x to i96*
  store i96 %0, i96* %.0..sroa_cast, align 8
  %.0..sroa_cast3 = bitcast [6 x i16]* %y to i96*
  store i96 %1, i96* %.0..sroa_cast3, align 8
  %_11.i.i.i = bitcast [6 x i16]* %x to i8*
  %_14.i.i.i = bitcast [6 x i16]* %y to i8*
  %bcmp.i.i.i = call i32 `@bcmp(i8*` nonnull dereferenceable(12) %_11.i.i.i, i8* nonnull dereferenceable(12) %_14.i.i.i, i64 12) #2, !alias.scope !2
  %2 = icmp eq i32 %bcmp.i.i.i, 0
  ret i1 %2
}
```
```x86
playground::demo: # `@playground::demo`
	sub	rsp, 32
	mov	qword ptr [rsp], rdi
	mov	dword ptr [rsp + 8], esi
	mov	qword ptr [rsp + 16], rdx
	mov	dword ptr [rsp + 24], ecx
	xor	rdi, rdx
	xor	esi, ecx
	or	rsi, rdi
	sete	al
	add	rsp, 32
	ret
```

After:
```llvm
define zeroext i1 `@_ZN4mini4demo17h7a8994aaa314c981E(i96` %0, i96 %1) unnamed_addr #0 {
start:
  %2 = icmp eq i96 %0, %1
  ret i1 %2
}
```
```x86
_ZN4mini4demo17h7a8994aaa314c981E:
	xor	rcx, r8
	xor	edx, r9d
	or	rdx, rcx
	sete	al
	ret
```
2021-07-09 09:16:27 +00:00
bors
95fb131521 Auto merge of #86904 - m-ou-se:prelude-collision-check-trait, r=nikomatsakis
Check FromIterator trait impl in prelude collision check.

Fixes #86902.
2021-07-09 06:35:42 +00:00
Scott McMurray
b63b2f1e42 PR feedback
- Add `:Sized` assertion in interpreter impl
- Use `Scalar::from_bool` instead of `ScalarInt: From<bool>`
- Remove unneeded comparison in intrinsic typeck
- Make this UB to call with undef, not just return undef in that case
2021-07-08 14:55:57 -07:00
Scott McMurray
2456495a26 Stop generating allocas+memcmp for simple array equality 2021-07-08 14:55:54 -07:00
Scott McMurray
d05eafae2f Move the PartialEq and Eq impls for arrays to a separate file 2021-07-08 14:53:37 -07:00
bors
8b87e85394 Auto merge of #86930 - tspiteri:int_log10, r=kennytm
special case for integer log10

Now that #80918 has been merged, this PR provides a faster version of `log10`.

The PR also adds some tests for values close to all powers of 10.
2021-07-08 20:19:00 +00:00
Guillaume Gomez
d12b16887b
Rollup merge of #86726 - sexxi-goose:use-diagnostic-item-for-rfc2229-migration, r=nikomatsakis
Use diagnostic items instead of lang items for rfc2229 migrations

This PR removes the `Send`, `UnwindSafe` and `RefUnwindSafe` lang items introduced in https://github.com/rust-lang/rust/pull/84730, and uses diagnostic items instead to check for `Send`, `UnwindSafe` and `RefUnwindSafe` traits for RFC2229 migrations.

r? ```@nikomatsakis```
2021-07-08 18:30:33 +02:00
bors
0cd0709f19 Auto merge of #86823 - the8472:opt-chunk-tra, r=kennytm
Optimize unchecked indexing into chunks and chunks_mut

Fixes #53340

```
# BEFORE

$ rustc +nightly -Copt-level=3 -Ccodegen-units=1 -Clto=fat chunks.rs
$ perf stat ./chunks

 Performance counter stats for './chunks':

          3,177.03 msec task-clock                #    1.000 CPUs utilized
                 4      context-switches          #    0.001 K/sec
                 0      cpu-migrations            #    0.000 K/sec
           984,006      page-faults               #    0.310 M/sec
    13,092,199,322      cycles                    #    4.121 GHz                      (83.29%)
       384,543,475      stalled-cycles-frontend   #    2.94% frontend cycles idle     (83.35%)
     7,414,280,722      stalled-cycles-backend    #   56.63% backend cycles idle      (83.38%)
    50,493,980,662      instructions              #    3.86  insn per cycle
                                                  #    0.15  stalled cycles per insn  (83.29%)
     6,625,375,297      branches                  # 2085.396 M/sec                    (83.38%)
         3,087,652      branch-misses             #    0.05% of all branches          (83.31%)

       3.178079469 seconds time elapsed

       2.327156000 seconds user
       0.762041000 seconds sys

# AFTER

$ ./build/x86_64-unknown-linux-gnu/stage1/bin/rustc -Copt-level=3 -Ccodegen-units=1 -Clto=fat chunks.rs
$ perf stat ./chunks

 Performance counter stats for './chunks':

          2,705.76 msec task-clock                #    1.000 CPUs utilized
                 4      context-switches          #    0.001 K/sec
                 0      cpu-migrations            #    0.000 K/sec
           984,005      page-faults               #    0.364 M/sec
    11,156,763,039      cycles                    #    4.123 GHz                      (83.26%)
       342,198,882      stalled-cycles-frontend   #    3.07% frontend cycles idle     (83.37%)
     6,486,263,637      stalled-cycles-backend    #   58.14% backend cycles idle      (83.37%)
    40,553,476,617      instructions              #    3.63  insn per cycle
                                                  #    0.16  stalled cycles per insn  (83.37%)
     6,668,429,113      branches                  # 2464.532 M/sec                    (83.37%)
         3,099,636      branch-misses             #    0.05% of all branches          (83.26%)

       2.706725288 seconds time elapsed

       1.782083000 seconds user
       0.848424000 seconds sys
```
2021-07-08 09:44:52 +00:00
Yuki Okushi
01474ad92c
Rollup merge of #86956 - cuviper:unalias-every, r=m-ou-se
Revert "Add "every" as a doc alias for "all"."

This reverts commit 35450365ac (#81697) for "every" and closes #86554 in kind for "some".

The new [doc alias policy](https://std-dev-guide.rust-lang.org/documentation/doc-alias-policy.html) is that we don't want language-specific aliases like these JavaScript names, and we especially don't want to conflict with real names. While "every" is okay in the latter regard, its natural pair "some" makes a doc-search collision with `Option::Some`.

r? ```@m-ou-se```
2021-07-08 10:44:37 +09:00
Mara Bos
e3044432c7 Move [debug_]assert_matches to mod {core, std}::assert. 2021-07-08 02:33:36 +02:00
Josh Stone
ace3989d55 Revert "Add "every" as a doc alias for "all"."
This reverts commit 35450365ac.
2021-07-07 13:13:26 -07:00
Swordelf2
7677f5fe31
Fix typo in ops::Drop docs 2021-07-07 22:26:32 +03:00
Mara Bos
60535441c8 Check FromIterator trait impl in prelude collision check. 2021-07-07 13:26:38 +00:00
Trevor Spiteri
ed76c11202 special case for integer log10 2021-07-07 14:10:05 +02:00
Trevor Spiteri
b0f98c60a6 test integer log10 values close to all powers of 10 2021-07-07 14:07:32 +02:00
Yuki Okushi
fe3d6a74d9
Rollup merge of #86906 - juniorbassani:update-sync-docs, r=yaahc
Replace deprecated compare_and_swap and fix typo in core::sync::atomic::{fence, compiler_fence} docs
2021-07-07 12:17:42 +09:00
Yuki Okushi
c630b6b0fc
Rollup merge of #86880 - m-ou-se:test-manuallydrop-clone-from, r=Mark-Simulacrum
Test ManuallyDrop::clone_from.

See #86288
2021-07-07 12:17:41 +09:00
Yuki Okushi
7e95290caa
Rollup merge of #86717 - rylev:rename, r=nikomatsakis
Rename some Rust 2021 lints to better names

Based on conversation in https://github.com/rust-lang/rust/issues/85894.

Rename a bunch of Rust 2021 related lints:

Lints that are officially renamed because they are already in beta or stable:
* `disjoint_capture_migration` => `rust_2021_incompatible_closure_captures`
* `or_patterns_back_compat` => `rust_2021_incompatible_or_patterns`
* `non_fmt_panic` => `non_fmt_panics`

Lints that are renamed but don't require any back -compat work since they aren't yet in stable:
* `future_prelude_collision` => `rust_2021_prelude_collisions`
* `reserved_prefix` => `rust_2021_token_prefixes`

Lints that have been discussed but that I did not rename:
* ~`non_fmt_panic` and `bare_trait_object`: is making this plural worth the headache we might cause users?~
* `array_into_iter`: I'm unsure of a good name and whether bothering users with a name change is worth it.

r? `@nikomatsakis`
2021-07-07 12:17:39 +09:00
Yuki Okushi
9bbc470e97
Rollup merge of #80918 - yoshuawuyts:int-log2, r=m-ou-se
Add Integer::log variants

_This is another attempt at landing https://github.com/rust-lang/rust/pull/70835, which was approved by the libs team but failed on Android tests through Bors. The text copied here is from the original issue. The only change made so far is the addition of non-`checked_` variants of the log methods._

_Tracking issue: #70887_

---

This implements `{log,log2,log10}` methods for all integer types. The implementation was provided by `@substack` for use in the stdlib.

_Note: I'm not big on math, so this PR is a best effort written with limited knowledge. It's likely I'll be getting things wrong, but happy to learn and correct. Please bare with me._

## Motivation
Calculating the logarithm of a number is a generally useful operation. Currently the stdlib only provides implementations for floats, which means that if we want to calculate the logarithm for an integer we have to cast it to a float and then back to an int.

> would be nice if there was an integer log2 instead of having to either use the f32 version or leading_zeros() which i have to verify the results of every time to be sure

_— [`@substack,` 2020-03-08](https://twitter.com/substack/status/1236445105197727744)_

At higher numbers converting from an integer to a float we also risk overflows. This means that Rust currently only provides log operations for a limited set of integers.

The process of doing log operations by converting between floats and integers is also prone to rounding errors. In the following example we're trying to calculate `base10` for an integer. We might try and calculate the `base2` for the values, and attempt [a base swap](https://www.rapidtables.com/math/algebra/Logarithm.html#log-rules) to arrive at `base10`. However because we're performing intermediate rounding we arrive at the wrong result:

```rust
// log10(900) = ~2.95 = 2
dbg!(900f32.log10() as u64);

// log base change rule: logb(x) = logc(x) / logc(b)
// log2(900) / log2(10) = 9/3 = 3
dbg!((900f32.log2() as u64) / (10f32.log2() as u64));
```
_[playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=6bd6c68b3539e400f9ca4fdc6fc2eed0)_

This is somewhat nuanced as a lot of the time it'll work well, but in real world code this could lead to some hard to track bugs. By providing correct log implementations directly on integers we can help prevent errors around this.

## Implementation notes

I checked whether LLVM intrinsics existed before implementing this, and none exist yet. ~~Also I couldn't really find a better way to write the `ilog` function. One option would be to make it a private method on the number, but I didn't see any precedent for that. I also didn't know where to best place the tests, so I added them to the bottom of the file. Even though they might seem like quite a lot they take no time to execute.~~

## References

- [Log rules](https://www.rapidtables.com/math/algebra/Logarithm.html#log-rules)
- [Rounding error playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=6bd6c68b3539e400f9ca4fdc6fc2eed0)
- [substack's tweet asking about integer log2 in the stdlib](https://twitter.com/substack/status/1236445105197727744)
- [Integer Logarithm, A. Jaffer 2008](https://people.csail.mit.edu/jaffer/III/ilog.pdf)
2021-07-07 12:17:32 +09:00
Jon Gjengset
cf40292122
Link tracking issue for pin_deref_mut 2021-07-06 16:59:45 -07:00
Ryan Levick
a902e25f58 Add s to non_fmt_panic 2021-07-06 20:12:56 +02:00
Ryan Levick
1d49658f5c Change or_patterns_back_compat lint to rust_2021_incompatible_or_patterns 2021-07-06 20:11:45 +02:00
Júnior Bassani
0d61e6e8d6
Fix typo in core::sync::atomic::compiler_fence example 2021-07-06 10:53:14 -03:00
Júnior Bassani
a87fb18027
Replace deprecated compare_and_swap by compare_exchange_weak in core::sync::atomic::fence example 2021-07-06 10:50:17 -03:00
Yuki Okushi
470ed70a86
Rollup merge of #86852 - Amanieu:remove_doc_aliases, r=joshtriplett
Remove some doc aliases

As per the new doc alias policy in https://github.com/rust-lang/std-dev-guide/pull/25, this removes some controversial doc aliases:
- `malloc`, `alloc`, `realloc`, etc.
- `length` (alias for `len`)
- `delete` (alias for `remove` in collections and also file/directory deletion)

r? `@joshtriplett`
2021-07-06 02:33:16 +09:00
Yuki Okushi
add24d2f4f
Rollup merge of #85377 - ijackson:abort-docs, r=m-ou-se
aborts: Clarify documentation and comments

In the docs for intrinsics::abort():

 * Strengthen the recommendation by to use process::abort instead.
 * Document the fact that it sometimes (ab)uses an LLVM debug trap and what the likely consequences are.
 * State that the precise behaviour is unstable.

In the docs for process::abort():

 * Promise that we have the same behaviour as C `abort()`.
 * Document the likely consequences, including, specifically, the consequences on Unix.

In the internal comment for unix::abort_internal:

 * Refer to the public docs for the public API functions.
 * Correct and expand the description of libc::abort.  Specifically:
 * Do not claim that abort() unregisters signal handlers.  It doesn't; it honours the SIGABRT handler.
 * Discuss, extensively, the issue with abort() flushing stdio buffers.
 * Describe the glibc behaviour in some detail.

Co-authored-by: Mark Wooding <mdw@distorted.org.uk>
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

Fixes #40230
2021-07-06 02:33:13 +09:00
bors
6e9b3696d4 Auto merge of #84560 - cjgillot:inline-iter, r=m-ou-se
Inline Iterator as IntoIterator.

For some reason, it appears on rustc's own perf stats.
2021-07-05 13:12:07 +00:00
Mara Bos
3d20b2a14f Test ManuallyDrop::clone_from. 2021-07-05 11:55:45 +00:00
Mara Bos
f73a555fc9 Use american spelling for behaviour
Co-authored-by: Yuki Okushi <jtitor@2k36.org>
2021-07-05 12:43:03 +02:00
Ian Jackson
19c347ede9 Talk about "terminate" rather than "die"
Adapted from a suggestion by @m-ou-se.

Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
2021-07-05 12:43:03 +02:00
Ian Jackson
44852e0603 Talk about invalid instructions rather than debug traps
And withdraw the allegation of "abuse".

Adapted from a suggestion by @m-ou-se.

Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
2021-07-05 12:43:03 +02:00
Ian Jackson
de19e4d2b6 abort docs: Do not claim that intrinsics::abort is always a debug trap
As per discussion here
 https://github.com/rust-lang/rust/pull/85377#pullrequestreview-660460501

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
2021-07-05 12:43:02 +02:00
Ian Jackson
a8bb7fa76b aborts: Clarify documentation and comments
In the docs for intrinsics::abort():

 * Strengthen the recommendation by to use process::abort instead.
 * Document the fact that it (ab)uses an LLVM debug trap and what the
   likely consequences are.
 * State that the precise behaviour is unstable.

In the docs for process::abort():

 * Promise that we have the same behaviour as C `abort()`.
 * Document the likely consequences, including, specifically, the
   consequences on Unix.

In the internal comment for unix::abort_internal:

 * Refer to the public docs for the public API functions.
 * Correct and expand the description of libc::abort.  Specifically:
 * Do not claim that abort() unregisters signal handlers.  It doesn't;
   it honours the SIGABRT handler.
 * Discuss, extensively, the issue with abort() flushing stdio buffers.
 * Describe the glibc behaviour in some detail.

Co-authored-by: Mark Wooding <mdw@distorted.org.uk>
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
2021-07-05 12:43:00 +02:00
bors
b3d11f95cc Auto merge of #86598 - yoshuawuyts:poll-method-docs, r=JohnTitor
Add examples to the various methods of `core::task::Poll`

This improves the documentation of the various methods of [`core::task::Poll`](https://doc.rust-lang.org/std/task/enum.Poll.html). These currently have fairly simple docs with no examples. This PR changes these methods to be closer to `core::option::Option` and adds usage examples (and importantly: tests!) to `Poll`'s methods.

cc/ `@rust-lang/wg-async-foundations`

## Screenshots

<details>
<summary>View generated rustdoc page</summary>
<image src="https://user-images.githubusercontent.com/2467194/123286616-59ee9b00-d50e-11eb-9e02-40269070f904.png" alt="Poll in core::task"></details>
2021-07-04 20:00:57 +00:00
bors
90442458ac Auto merge of #86048 - nbdd0121:no_floating_point, r=Amanieu
core: add unstable no_fp_fmt_parse to disable float formatting code

In some projects (e.g. kernel), floating point is forbidden. They can disable
hardware floating point support and use `+soft-float` to avoid fp instructions
from being generated, but as libcore contains the formatting code for `f32`
and `f64`, some fp intrinsics are depended. One could define stubs for these
intrinsics that just panic [1], but it means that if any formatting functions
are accidentally used, mistake can only be caught during the runtime rather
than during compile-time or link-time, and they consume a lot of space without
LTO.

This patch provides an unstable cfg `no_fp_fmt_parse` to disable these.
A panicking stub is still provided for the `Debug` implementation (unfortunately)
because there are some SIMD types that use `#[derive(Debug)]`.

[1]: https://lkml.org/lkml/2021/4/14/1028
2021-07-04 14:18:57 +00:00
bors
308fc2322b Auto merge of #86213 - jhpratt:stabilize-const-from_utf8_unchecked, r=JohnTitor
Stabilize `str::from_utf8_unchecked` as `const`

This stabilizes `unsafe fn str::from_utf8_unchecked` as `const` pending FCP on #75196. By the time FCP finishes, the beta will have already been cut, so I've set 1.55 as the stable-since version.

(should also be +relnotes but I don't have the permission to do that)

r? `@m-ou-se`

Closes #75196
2021-07-04 11:56:55 +00:00
Charles Lew
0d1919c7ab Remove the deprecated core::raw and std::raw module. 2021-07-03 14:03:27 +08:00
Gary Guo
ec7292ad3c core: add unstable no_fp_fmt_parse to disable float fmt/parse code
In some projects (e.g. kernel), floating point is forbidden. They can disable
hardware floating point support and use `+soft-float` to avoid fp instructions
from being generated, but as libcore contains the formatting code for `f32`
and `f64`, some fp intrinsics are depended. One could define stubs for these
intrinsics that just panic [1], but it means that if any formatting functions
are accidentally used, mistake can only be caught during the runtime rather
than during compile-time or link-time, and they consume a lot of space without
LTO.

This patch provides an unstable cfg `no_fp_fmt_parse` to disable these.
A panicking stub is still provided for the `Debug` implementation (unfortunately)
because there are some SIMD types that use `#[derive(Debug)]`.

[1]: https://lkml.org/lkml/2021/4/14/1028
2021-07-02 22:52:37 +01:00
The8472
24094a04b6 optimize chunks and chunks_mut 2021-07-02 23:14:05 +02:00
Yuki Okushi
7fb3c29dc6
Rollup merge of #86308 - bstrie:intrinsafe, r=JohnTitor
Docs: clarify that certain intrinsics are not unsafe

As determined by the hardcoded list at 003b8eadd7/compiler/rustc_typeck/src/check/intrinsic.rs (L59-L92)
2021-07-03 03:15:10 +09:00
Guillaume Gomez
cd3a48fdb6
Rollup merge of #86797 - inquisitivecrystal:bound-cloned, r=jyn514
Stabilize `Bound::cloned()`

This PR stabilizes the function `Bound::cloned()`.

Closes #61356.
2021-07-02 11:35:31 +02:00
Taylor Yu
2b4a6aa149 fix missing word 2021-07-01 19:14:27 -05:00
Aris Merchant
f2b21e2d0b Stabilize Bound::cloned() 2021-07-01 17:09:57 -07:00
Josh Stone
6f5e933adb Make the specialized Fuse still deal with None 2021-06-30 16:10:33 -07:00
Amanieu d'Antras
e2536bb271 Remove "length" doc aliases 2021-06-30 20:28:51 +01:00
Roxane
cc3af7091c Rename variable 2021-06-29 20:26:37 -04:00
Roxane Fruytier
3e569dd2df Remove lang items Send, UnwindSafe and RefUnwindSafe 2021-06-29 17:47:57 -04:00
Mark Rousskov
06661ba759 Update to new bootstrap compiler 2021-06-28 11:30:49 -04:00
bors
9cdb2d3d59 Auto merge of #86655 - jonas-schievink:const-arguments-as-str, r=kennytm
Make `fmt::Arguments::as_str` unstably const

Motivation: mostly to move "panic!() in const contexts" forward, making use of `as_str` was mentioned in https://github.com/rust-lang/rust/issues/85194#issuecomment-852345377 and seems like the simplest way forward.
2021-06-27 15:45:29 +00:00
Albin Hedman
22fe76d97d
Add reference to tracking issue #86302 for const_ptr_write 2021-06-27 12:05:19 +02:00
Albin Hedman
1aa032f506
Add reference to issue for const_intrinsic_copy in ptr::write 2021-06-27 12:05:19 +02:00
Albin Hedman
6c890bb969
Revert "Revert tests added by PR 81167."
This reverts commit cebfcd3256.
2021-06-27 12:05:17 +02:00
Albin Hedman
5fbb1354ce
Revert "Revert effects of PRs 81167 and 83091."
This reverts commit 9d96b0ed8c.
2021-06-27 12:05:16 +02:00
Jonas Schievink
b3fbfe474b Make fmt::Arguments::as_str unstably const 2021-06-27 03:54:06 +02:00
bors
481971978f Auto merge of #86586 - Smittyvb:https-everywhere, r=petrochenkov
Use HTTPS links where possible

While looking at #86583, I wondered how many other (insecure) HTTP links were in `rustc`. This changes most other `http` links to `https`. While most of the links are in comments or documentation, there are a few other HTTP links that are used by CI that are changed to HTTPS.

Notes:
- I didn't change any to or in licences
- Some links don't support HTTPS :(
- Some `http` links were dead, in those cases I upgraded them to their new places (all of which used HTTPS)
2021-06-26 08:24:31 +00:00
bors
6830052c7b Auto merge of #86637 - ehuss:spellings, r=dtolnay
Fix a few misspellings.
2021-06-26 05:09:27 +00:00
Eric Huss
6235e6f93f Fix a few misspellings. 2021-06-25 13:18:56 -07:00
Yoshua Wuyts
9f579968cd Add Integer::{log,log2,log10} variants 2021-06-25 18:52:46 +02:00
Yuki Okushi
9e4649995f
Rollup merge of #86592 - jhpratt:non_exhaustive, r=JohnTitor
Use `#[non_exhaustive]` where appropriate

Due to the std/alloc split, it is not possible to make `alloc::collections::TryReserveError::AllocError` non-exhaustive without having an unstable, doc-hidden method to construct (which negates the benefits from `#[non_exhaustive]`).

`@rustbot` label +C-cleanup +T-libs +S-waiting-on-review
2021-06-26 00:42:12 +09:00
est31
8e328be73d Fix grammar mistake
present perfect passive constructions need to use the past participle form,
which for run is "run".
2021-06-25 00:54:34 +02:00
est31
5585cce06c Add another example 2021-06-25 00:54:34 +02:00
Yoshua Wuyts
a06ee821b7 Document the various methods of core::task::Poll 2021-06-25 00:41:56 +02:00
Taylor Yu
c196cc9f12 option/result overviews: address feedback
(Most of these are from a review by joshtriplett. Thanks!)

Fix errors in `as_pin_ref` and `as_pin_mut` in the "Adapters for
working with references" overview.

Reword some headings about transformation methods.

Reclassify `map`, `map_or`, `map_or_else`, `map_err`, etc. to more
accurately reflect which variants they transform.

Document `Debug` requirement for `get_or_insert_default`.

Reword text about `take` and `replace` to be more accurate.

Add examples for the `Product` and `Sum` traits.

Also:

Move link reference definitions closer to their uses. Warn about making
link reference definintions for `err` and `ok`. Avoid making other link
reference definitions that might conflict in the future (foreign methods
that share a name with local ones, etc.)

Write out the generics of `Option` and `Result` when the following
text refers to the type parameters.
2021-06-24 12:33:51 -05:00
Jacob Pratt
5d85130995
Partially stabilize const_slice_first_last 2021-06-24 05:16:45 -04:00
Scott McMurray
579d19bc6a Use hash_one to simplify some other doctests 2021-06-24 01:30:48 -07:00
Scott McMurray
63d28192da Add tracking issue and rename to hash_one 2021-06-24 01:30:48 -07:00
Scott McMurray
a3eb9e3db2 Add BuildHasher::hash_of as unstable 2021-06-24 01:30:48 -07:00
Jacob Pratt
3f14f4b3ce
Use #[non_exhaustive] where appropriate
Due to the std/alloc split, it is not possible to make
`alloc::collections::TryReserveError::AllocError` non-exhaustive without
having an unstable, doc-hidden method to construct (which negates the
benefits from `#[non_exhaustive]`.
2021-06-24 04:16:11 -04:00
Yuki Okushi
0fa4f0ba62
Rollup merge of #86415 - Kmeakin:iterator-associativity-docs, r=dtolnay
Document associativity of iterator folds.

Document the associativity of `Iterator::fold` and
`DoubleEndedIterator::rfold` and add examples demonstrating this.
Add links to direct users to the fold of the opposite associativity.
2021-06-24 13:47:34 +09:00
Smitty
bdfcb88e8b Use HTTPS links where possible 2021-06-23 16:26:46 -04:00
Yoshua Wuyts
660f585413 Add core::stream::from_iter 2021-06-23 17:49:26 +02:00
bors
8cb207ae69 Auto merge of #86386 - inquisitivecrystal:better-errors-for-display-traits-v3, r=estebank
Better errors for Debug and Display traits

Currently, if someone tries to pass value that does not implement `Debug` or `Display` to a formatting macro, they get a very verbose and confusing error message. This PR changes the error messages for missing `Debug` and `Display` impls to be less overwhelming in this case, as suggested by #85844. I was a little less aggressive in changing the error message than that issue proposed. Still, this implementation would be enough to reduce the number of messages to be much more manageable.

After this PR, information on the cause of an error involving a `Debug` or `Display` implementation would suppressed if the requirement originated within a standard library macro. My reasoning was that errors originating from within a macro are confusing when they mention details that the programmer can't see, and this is particularly problematic for `Debug` and `Display`, which are most often used via macros. It is possible that either a broader or a narrower criterion would be better. I'm quite open to any feedback.

Fixes #85844.
2021-06-23 03:16:04 +00:00
Dylan DPC
6023ac2c8d
Rollup merge of #86521 - the8472:add-footgun-comments, r=RalfJung
Add comments around code where ordering is important due for panic-safety

Iterators contain arbitrary code which may panic. Unsafe code has to be
careful to do its state updates at the right point between calls that may panic.

As requested in https://github.com/rust-lang/rust/pull/86452#discussion_r655153948

r? `@RalfJung`
2021-06-23 00:20:20 +02:00
Taylor Yu
771f35ce84 Some<T> is not a type, etc 2021-06-22 15:35:14 -05:00
The8472
e0d70153cd Add comments around code where ordering is important due for panic-safety
Iterators contain arbitrary code which may panic. Unsafe code has to be
careful to do its state updates at the right point between calls
that may panic.
2021-06-22 19:06:55 +02:00
bors
75ed34223a Auto merge of #84910 - eopb:stabilize_int_error_matching, r=yaahc
stabilize `int_error_matching`

closes #22639

> It has been over half a year since https://github.com/rust-lang/rust/pull/77640#pullrequestreview-511263516, and the indexing question is rejected in https://github.com/rust-lang/rust/pull/79728#pullrequestreview-633030341, so I guess we can submit another stabilization attempt? 😉

_Originally posted by `@kennytm` in https://github.com/rust-lang/rust/issues/22639#issuecomment-831738266_
2021-06-22 09:30:15 +00:00
Ethan Brierley
52a6885c50 postpone stabilizaton by one release 2021-06-22 10:20:56 +01:00
Aris Merchant
20ea5fedea Change Debug unimplemented message per request 2021-06-22 00:38:31 -07:00
bors
2c04f0bb17 Auto merge of #86527 - JohnTitor:rollup-cbu78g4, r=JohnTitor
Rollup of 11 pull requests

Successful merges:

 - #85054 (Revert SGX inline asm syntax)
 - #85182 (Move `available_concurrency` implementation to `sys`)
 - #86037 (Add `io::Cursor::{remaining, remaining_slice, is_empty}`)
 - #86114 (Reopen #79692 (Format symbols under shared frames))
 - #86297 (Allow to pass arguments to rustdoc-gui tool)
 - #86334 (Resolve type aliases to the type they point to in intra-doc links)
 - #86367 (Fix comment about rustc_inherit_overflow_checks in abs().)
 - #86381 (Add regression test for issue #39161)
 - #86387 (Remove `#[allow(unused_lifetimes)]` which is now unnecessary)
 - #86398 (Add regression test for issue #54685)
 - #86493 (Say "this enum variant takes"/"this struct takes" instead of "this function takes")

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
2021-06-22 01:14:31 +00:00
Yuki Okushi
8389cd3a1a
Rollup merge of #86367 - m-ou-se:fix-abs-comment, r=scottmcm
Fix comment about rustc_inherit_overflow_checks in abs().
2021-06-22 07:37:51 +09:00
bors
4573a4a879 Auto merge of #86383 - shamatar:slice_len_lowering, r=bjorn3
Add MIR pass to lower call to `core::slice::len` into `Len` operand

During some larger experiment with range analysis I've found that code like `let l = slice.len()` produces different MIR then one found in bound checks. This optimization pass replaces terminators that are calls to `core::slice::len` with just a MIR operand and Goto terminator.

It uses some heuristics to remove the outer borrow that is made to call `core::slice::len`, but I assume it can be eliminated, just didn't find how.

Would like to express my gratitude to `@oli-obk` who helped me a lot on Zullip
2021-06-21 22:24:13 +00:00
Yuki Okushi
504c378159
Rollup merge of #86452 - the8472:fix-zip-drop-safety, r=m-ou-se
fix panic-safety in specialized Zip::next_back

This was unsound since a panic in a.next_back() would result in the
length not being updated which would then lead to the same element
being revisited in the side-effect preserving code.

fixes #86443
2021-06-21 09:42:17 +09:00
Yuki Okushi
e6732e05e4
Rollup merge of #85637 - RalfJung:partial-ord, r=m-ou-se
document PartialEq, PartialOrd, Ord requirements more explicitly

This is the result of discussion in https://github.com/rust-lang/rust/issues/50230, in particular [this summary comment](https://github.com/rust-lang/rust/issues/50230#issuecomment-392819364).

Fixes https://github.com/rust-lang/rust/issues/50230.
2021-06-21 09:42:13 +09:00
Taylor Yu
9a00fd049b add more to result overview 2021-06-20 17:22:03 -05:00
Alex Vlasov
aa53928ed7 Squashed implementation of the pass 2021-06-20 16:09:42 +02:00
The8472
b4734b7c38 disable test on platforms that don't support unwinding 2021-06-20 12:20:05 +02:00
bstrie
16168dd114 Clarify that certain intrinsics are not unsafe 2021-06-19 12:22:39 -04:00
Yuki Okushi
ad79aba2bc
Rollup merge of #86453 - akiselev:patch-1, r=dtolnay
stdlib: Fix typo in internal RefCell docs

`BorroeError` => `BorrowError` in [cell.rs](https://github.com/rust-lang/rust/blob/master/library/core/src/cell.rs#L581)
2021-06-19 10:14:15 +09:00
Yuki Okushi
90e82c950b
Rollup merge of #86397 - Eosis:alter-cell-docs, r=JohnTitor
Alter std::cell::Cell::get_mut documentation

I felt that there was some inconsistency between between Cell and RefCell with regards to their `get_mut` method documentation: `RefCell` flags this method as "unusual" in that it takes `&mut self`, while `Cell` does not. I attempted to flag this in `Cell`s documentation as well, and point to `RefCell`s method in the case where it is required.

Find relevant parts of docs and the new version below.

The current docs for `Cell::get_mut`:
> Returns a mutable reference to the underlying data.
This call borrows Cell mutably (at compile-time) which guarantees that we possess the only reference.

And `RefCell::get_mut`:
> Returns a mutable reference to the underlying data.
 This call borrows `RefCell` mutably (at compile-time) so there is no need for dynamic checks.
However be cautious: this method expects self to be mutable, which is generally not the case when using a `RefCell`. Take a look at the `borrow_mut` method instead if self isn’t mutable.
Also, please be aware that this method is only for special circumstances and is usually not what you want. In case of doubt, use `borrow_mut` instead.

My attempt to make `Cell::get_mut` clearer:
> Returns a mutable reference to the underlying data.
This call borrows `Cell` mutably (at compile-time) which guaranteesthat we possess the only reference.
However be cautious: this method expects `self` to be mutable, which is generally not the case when using a `Cell`. If you require interior mutability by reference, consider using `RefCell` which provides run-time checked mutable borrows through its `borrow_mut` method.
2021-06-19 10:14:10 +09:00
Alexander Kiselev
c688e70d66
Fixed typo BorroeError => BorrowError in RefCell docs 2021-06-18 17:43:18 -07:00
The8472
8b518542d0 fix panic-safety in specialized Zip::next_back
This was unsound since a panic in a.next_back() would result in the
length not being updated which would then lead to the same element
being revisited in the side-effect preserving code.
2021-06-19 02:20:51 +02:00
Karl Meakin
8eb0c0df0e Document associativity of iterator folds.
Document the associativity of `Iterator::fold` and
`DoubleEndedIterator::rfold` and add examples demonstrating this.
Add links to direct users to the fold of the opposite associativity.
2021-06-17 20:42:48 +01:00
Yuki Okushi
65d412b637
Rollup merge of #86389 - kpreid:sum, r=scottmcm
Make `sum()` and `product()` documentation hyperlinks refer to `Iterator` methods.

The previous linking seemed confusing: within "the sum() method on iterators", "sum()" was linked to `Sum::sum`, not `Iterator::sum`, even though the sentence is talking about the latter. I have rewritten the sentence to be, I believe, clearer, as well as changing the link destinations; applying the same change to the `Product` documentation as well as `Sum`.

I reviewed other traits in the same module and did not see similar issues, and previewed the results using `./x.py doc library/std`.
2021-06-17 21:56:46 +09:00
Rupert Rutledge
7cadf7bc01 Alter std::cell::Cell::get_mut documentation
I find this more consistent with RefCell's equivalent method.
2021-06-17 11:02:16 +01:00
Mara Bos
13bfbb4253 Fix comment about rustc_inherit_overflow_checks in abs(). 2021-06-17 10:02:08 +00:00
Jacob Hoffman-Andrews
910c7fa767 Add doc(hidden) to all __iterator_get_unchecked
This method on the Iterator trait is doc(hidden), and about half of
implementations were doc(hidden). This adds the attribute to the
remaining implementations.
2021-06-16 22:08:44 -07:00
Kevin Reid
cb2f8d9b02 Make sum() and product() hyperlinks refer to Iterator methods.
The previous linking seemed confusing: within "the sum() method on
iterators", "sum()" was linked to `Sum::sum`, not `Iterator::sum`, even
though the sentence is talking about the latter.

I have rewritten the sentence to be, I believe, clearer, as well as
changing the link destinations; applying the same change to the
`Product` documentation as well as `Sum`.
2021-06-16 17:52:33 -07:00
Yuki Okushi
27d5426bcf
Rollup merge of #86372 - snoyberg:patch-1, r=jonas-schievink
Typo correction: s/is/its
2021-06-17 05:55:02 +09:00
Yuki Okushi
b1fb32d165
Rollup merge of #86140 - scottmcm:array-hash-facepalm, r=kennytm
Mention the `Borrow` guarantee on the `Hash` implementations for Arrays and `Vec`

To remind people like me who forget about it and send PRs to make them different, and to (probably) get a test failure if the code is changed to no longer uphold it.
2021-06-17 05:54:54 +09:00
Michael Snoyman
770e8cc01e
Typo correction: s/is/its 2021-06-16 19:20:15 +03:00
Aris Merchant
f1f1c9b25b Improve errors for missing Debug and Display impls 2021-06-16 01:13:28 -07:00
Yuki Okushi
d476707a1f
Rollup merge of #86209 - tlyu:option-doc-typos, r=JohnTitor
fix minor wording/typo issues in core::option docs

These are just minor wording or typo things I came across while making other edits.
2021-06-16 13:31:07 +09:00
Yuki Okushi
7ceb706e9d
Rollup merge of #86200 - qwerty01:clone-doc-update, r=JohnTitor
Updates `Clone` docs for `Copy` comparison.

Quite a few people (myself included) have come under the impression that the difference between `Copy` and `Clone` is that `Copy` is cheap and `Clone` is expensive, where the actual difference is that `Copy` constrains the type to bit-wise copying, and `Clone` allows for more expensive operations. The source of this misconception is in the `Clone` docs, where the following line is in the description:

> Differs from `Copy` in that `Copy` is implicit and extremely inexpensive, while `Clone` is always explicit and may or may not be expensive.

The `Clone` documentation page also comes up before the `Copy` page on google when searching for "the difference between `Clone` and `Copy`".

This PR updates the documentation to clarify that "extremely inexpensive" means an "inexpensive bit-wise copy" to hopefully prevent future rust users from falling into this misunderstanding.
2021-06-16 13:31:06 +09:00
Jon Gjengset
b5e5a182ca
Update library/core/src/pin.rs
Co-authored-by: Ralf Jung <post@ralfj.de>
2021-06-15 20:47:43 -04:00
est31
1c8033f77f Split MaybeUninit::write into new feature gate and stabilize it 2021-06-16 02:47:05 +02:00
bors
684ca335d5 Auto merge of #85406 - VillSnow:integrate_binary_search, r=JohnTitor
Integrate binary search codes of binary_search_by and partition_point

For now partition_point has own binary search code piece.
It is because binary_search_by had called the comparer more times and the author (=me) wanted to avoid it.

However, now binary_search_by uses the comparer minimum times. (#74024)
So it's time to integrate them.

The appearance of the codes are a bit different but both use completely same logic.
2021-06-15 22:56:41 +00:00
Yuki Okushi
891ceab0ea
Rollup merge of #86294 - m-ou-se:edition-prelude-modules, r=joshtriplett
Stabilize {std, core}::prelude::rust_*.

This stabilizes the `{core, std}::prelude::{rust_2015, rust_2018, rust_2021}` modules.

The usage of these modules as the prelude in those editions was already stabilized. This just stabilizes the modules themselves, making it possible for a user to explicitly refer to them.

Tracking issue: https://github.com/rust-lang/rust/issues/85684

FCP on the RFC that included this finished here: https://github.com/rust-lang/rfcs/pull/3114#issuecomment-840577395
2021-06-15 17:40:14 +09:00
Yuki Okushi
e84ee522a9
Rollup merge of #86220 - est31:maybe-uninit-extra, r=RalfJung
Improve maybe_uninit_extra docs

For reasoning, see https://github.com/rust-lang/rust/issues/63567#issuecomment-858640987
2021-06-15 17:40:10 +09:00
Yuki Okushi
5936ecc24f
Rollup merge of #85608 - scottmcm:stabilize-control-flow-enum-basics, r=m-ou-se
Stabilize `ops::ControlFlow` (just the type)

Tracking issue: https://github.com/rust-lang/rust/issues/75744 (which also tracks items *not* closed by this PR).

With the new `?` desugar implemented, [it's no longer possible to mix `Result` and `ControlFlow`](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=13feec97f5c96a9d791d97f7de2d49a6).  (At the time of making this PR, godbolt was still on the 2021-05-01 nightly, where you can see that [the mixing example compiled](https://rust.godbolt.org/z/13Ke54j16).)  That resolves the only blocker I know of, so I'd like to propose that `ControlFlow` be considered for stabilization.

Its basic existence was part of https://github.com/rust-lang/rfcs/pull/3058, where it got a bunch of positive comments (examples [1](https://github.com/rust-lang/rfcs/pull/3058#issuecomment-758277325) [2](https://github.com/rust-lang/rfcs/pull/3058#pullrequestreview-592106494) [3](https://github.com/rust-lang/rfcs/pull/3058#issuecomment-784444155) [4](https://github.com/rust-lang/rfcs/pull/3058#issuecomment-797031584)).  Its use in the compiler has been well received (https://github.com/rust-lang/rust/pull/78182#issuecomment-713695594), and there are ecosystem updates interested in using it (https://github.com/rust-itertools/itertools/issues/469#issuecomment-677729589, https://github.com/jonhoo/rust-imap/issues/194).

As this will need an FCP, picking a libs member manually:
r? `@m-ou-se`

## Stabilized APIs

```rust
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum ControlFlow<B, C = ()> {
    /// Exit the operation without running subsequent phases.
    Break(B),
    /// Move on to the next phase of the operation as normal.
    Continue(C),
}
```

As well as using `?` on a `ControlFlow<B, _>` in a function returning `ControlFlow<B, _>`.  (Note, in particular, that there's no `From::from`-conversion on the `Break` value, the way there is for `Err`s.)

## Existing APIs *not* stabilized here

All the associated methods and constants: `break_value`, `is_continue`, `map_break`, [`CONTINUE`](https://doc.rust-lang.org/nightly/std/ops/enum.ControlFlow.html#associatedconstant.CONTINUE), etc.

Some of the existing methods in nightly seem reasonable, some seem like they should be removed, and some need more discussion to decide.  But none of them are *essential*, so [as in the RFC](https://rust-lang.github.io/rfcs/3058-try-trait-v2.html#methods-on-controlflow), they're all omitted from this PR.

They can be considered separately later, as further usage demonstrates which are important.
2021-06-15 17:40:08 +09:00
Yuki Okushi
1e14d397db
Rollup merge of #82179 - mbartlett21:patch-5, r=joshtriplett
Add functions `Duration::try_from_secs_{f32, f64}`

These functions allow constructing a Duration from a floating point value that could be out of range without panicking.

Tracking issue: #83400
2021-06-15 17:40:03 +09:00
Ralf Jung
45675f3d95
wording
Co-authored-by: Jane Lusby <jlusby42@gmail.com>
2021-06-15 10:20:08 +02:00
Taylor Yu
1b58d93bb2 add boolean operator example 2021-06-14 21:42:34 -05:00
Scott McMurray
590d4526e9 Master is 1.55 now :( 2021-06-14 10:37:05 -07:00
Mara Bos
65c1d35973 Stabilize {std, core}::prelude::rust_*. 2021-06-14 14:44:50 +00:00
bors
a216131c35 Auto merge of #86273 - JohnTitor:stabilize-maybe-uninit-ref, r=RalfJung
Stabilize `maybe_uninit_ref`

This stabilizes `assume_init_{ref,mut}`. FCP is complete: https://github.com/rust-lang/rust/issues/63568#issuecomment-590121300
The renaming was done by #76047 and FIXME was resolved by #76241, so I think we can now stabilize them finally 🎉
Still, it's const-unstable as `assert_inhabited` is unstable.

Closes #63568
2021-06-14 13:05:54 +00:00
mbartlett21
7803955cae Use try_from_secs_* in Duration::from_secs_* functions.
`Duration::from_secs_{f32, f64}` now use the results from the
non-panicking functions and unwrap it.
2021-06-14 12:17:53 +00:00