Deprecate atomic compare_and_swap method
Finish implementing [RFC 1443](https://github.com/rust-lang/rfcs/blob/master/text/1443-extended-compare-and-swap.md) (https://github.com/rust-lang/rfcs/pull/1443).
It was decided to deprecate `compare_and_swap` [back in Rust 1.12 already](https://github.com/rust-lang/rust/issues/31767#issuecomment-215903038). I can't find any info about that decision being reverted. My understanding is just that it has been forgotten. If there has been a decision on keeping `compare_and_swap` then it's hard to find, and even if this PR does not go through it can act as a place where people can find out about the decision being reverted.
Atomic operations are hard to understand, very hard. And it does not help that there are multiple similar methods to do compare and swap with. They are so similar that for a reader it might be hard to understand the difference. This PR aims to make that simpler by finally deprecating `compare_and_swap` which is essentially just a more limited version of `compare_exchange`. The documentation is also updated (according to the RFC text) to explain the differences a bit better.
Even if we decide to not deprecate `compare_and_swap`. I still think the documentation for the atomic operations should be improved to better describe their differences and similarities. And the documentation can be written nicer than the PR currently proposes, but I wanted to start somewhere. Most of it is just copied from the RFC.
The documentation for `compare_exchange` and `compare_exchange_weak` indeed describe how they work! The problem is that they are more complex and harder to understand than `compare_and_swap`. So for someone who does not fully grasp this they might fall back to using `compare_and_swap`. Making the documentation outline the similarities and differences might build a bridge for people so they can cross over to the more powerful and sometimes more efficient operations.
The conversions I do to avoid the `std` internal deprecation errors are very straight forward `compare_and_swap -> compare_exchange` changes where the orderings are just using the mapping in the new documentation. Only in one place did I use `compare_exchange_weak`. This can probably be improved further. But the goal here was not for those operations to be perfect. Just to not get worse and to allow the deprecation to happen.
Remove `DefPath` from `Visibility` and calculate it on demand
Depends on #80090 and should not be merged before. Helps with https://github.com/rust-lang/rust/issues/79103 and https://github.com/rust-lang/rust/issues/76382.
cc https://github.com/rust-lang/rust/pull/80014#issuecomment-746810284 - `@nnethercote` I figured it out! It was simpler than I expected :)
This brings the size of `clean::Visibility` down from 40 bytes to 8.
Note that this does *not* remove `clean::Visibility`, even though it's now basically the same as `ty::Visibility`, because the `Invsible` variant means something different from `Inherited` and I thought it would be be confusing to merge the two. See the new comments on `impl Clean for ty::Visibility` for details.
Update books
## nomicon
2 commits in d8383b65f7948c2ca19191b3b4bd709b403aaf45..a5a48441d411f61556b57d762b03d6874afe575d
2020-11-22 10:24:42 -0500 to 2020-12-06 10:39:41 +0900
- Update atomics.md (rust-lang/nomicon#249)
- Rename `AllocRef` to `Allocator` and `(de)alloc` to `(de)allocate` (rust-lang/nomicon#248)
## reference
2 commits in a8afdca5d0715b2257b6f8b9a032fd4dd7dae855..b278478b766178491a8b6f67afa4bcd6b64d977a
2020-11-30 06:44:46 -0800 to 2020-12-21 18:18:03 -0800
- Update unions for safe ManuallyDrop assignment. (rust-lang/reference#912)
- Removing ambiguity in type-layout.md (rust-lang/reference#911)
## book
25 commits in a190438d77d28041f24da4f6592e287fab073a61..5bb44f8b5b0aa105c8b22602e9b18800484afa21
2020-11-16 10:44:08 -0600 to 2020-12-18 20:07:31 -0500
- Make some further edits to rust-lang/book#2447
- Merge remote-tracking branch 'origin/pr/2447'
- Remove copied and dangling link brackets
- Merge remote-tracking branch 'origin/pr/2359'
- Override toolchain to nightly for run lints action. (rust-lang/book#2528)
- Remove an uneeded 'static lifetime (rust-lang/book#1752)
- Fixesrust-lang/book#2330. Clarify why the lock is held too long
- Update paragraph about rustfmt in Chapter 1.2 (rust-lang/book#2304)
- Clarify language around further from rust-lang/book#2418
- Merge remote-tracking branch 'origin/pr/2418'
- Merge remote-tracking branch 'origin/pr/2475'
- Add some further edits to rust-lang/book#2433
- Merge remote-tracking branch 'origin/pr/2433'
- Note all the method families to handle integer overflow
- Merge remote-tracking branch 'origin/pr/2405'
- Fixrust-lang/book#1855 - incorporate new reference cycle diagram
- Make some further edits to the changes in rust-lang/book#1886
- Merge remote-tracking branch 'origin/pr/1886'
- Make some further edits to rust-lang/book#1998
- Merge remote-tracking branch 'origin/pr/1998'
- Update Rust version and output (rust-lang/book#2518)
- Fix typo, regarding privileged ports being up to 1023 instead of 1024 (rust-lang/book#2509)
- Change "appendixes" to "appendices" in intro. (rust-lang/book#2498)
- Update 16-11 to use method call expression for `clone` (rust-lang/book#2511)
- Correct chapter 20 final listing (rust-lang/book#2516)
## rust-by-example
7 commits in 236c734a2cb323541b3394f98682cb981b9ec086..1cce0737d6a7d3ceafb139b4a206861fb1dcb2ab
2020-11-30 14:05:49 -0300 to 2020-12-21 17:36:29 -0300
- Add book.description in book.toml (rust-lang/rust-by-example#1397)
- Simplify the call of filter_map (rust-lang/rust-by-example#1396)
- Update README.md (rust-lang/rust-by-example#1382)
- Add missing main function in static life time example. (rust-lang/rust-by-example#1383)
- Clarify first matching arm and all possible values (rust-lang/rust-by-example#1395)
- Clarify distinction between for iter and into_iter (rust-lang/rust-by-example#1394)
- Drop extern crate (rust-lang/rust-by-example#1393)
Remove redundant test
Remove ignored test. This test can also be found at src/test/rustdoc-ui/intra-doc/double-anchor.rs and the second version isn't ignored.
r? ``@jyn514``
Clarify constructor splitting in exhaustiveness checking
I reworked the explanation of the algorithm completely to make it properly account for the various extensions we've added. This includes constructor splitting, which was previously not clearly included in the algorithm. This makes wildcards less magical; I added some detailed examples; and this distinguishes clearly between constructors that only make sense in patterns (like ranges) and those that make sense for values (like `Some`). This reformulation had been floating around in my mind for a while, and I'm quite happy with how it turned out. Let me know how you feel about it.
I also factored out all three cases of splitting (wildcards, ranges and slices) into dedicated structs to encapsulate the complicated bits.
I measured no perf impact but I don't trust my local measurements for refactors since https://github.com/rust-lang/rust/pull/79284.
r? `@varkor`
`@rustbot` modify labels: +A-exhaustiveness-checking
This implements support for applying PGO to the rustc compilation step (not
standard library or any tooling, including rustdoc). Expanding PGO to more tools
is not terribly difficult but will involve more work and greater CI time
commitment.
For the same reason of avoiding greater time commitment, this currently avoids
implementing for platforms outside of x86_64-unknown-linux-gnu, though in
practice it should be quite simple to extend over time to more platforms. The
initial implementation is intentionally minimal here to avoid too much work
investment before we start seeing wins for a subset of Rust users.
The choice of workloads to profile here is somewhat arbitrary, but the general
rationale was to aim for a small set that largely avoided time regressions on
perf.rust-lang.org's full suite of crates. The set chosen is libcore, cargo (and
its dependencies), and a few ad-hoc stress tests from perf.rlo. The stress tests
are arguably the most controversial, but they benefit those cases (avoiding
regressions) and do not really remove wins from other benchmarks.
The primary next step after this PR lands is to implement support for PGO in
LLVM. It is unclear whether we can afford a full LLVM rebuild in CI, though, so
the approach taken there may need to be more staggered. rustc-only PGO seems
well affordable on linux at least, giving us up to 20% wall time wins on some
crates for 15 minutes of extra CI time (1 hour up from 45 minutes).
The PGO data is uploaded to allow others to reuse it if attempting to reproduce
the CI build or potentially, in the future, on other platforms where an
off-by-one strategy is used for dist builds at minimal performance cost.
This does *not* currently work for associated items that are
auto-implemented by the compiler (e.g. `never::eq`), because they aren't
present in the source code. I plan to fix this in a follow-up PR.
Rename `overlapping_patterns` lint
As discussed in https://github.com/rust-lang/rust/issues/65477. I also tweaked a few things along the way.
r? `@varkor`
`@rustbot` modify labels: +A-exhaustiveness-checking
Acknowledge that `[CONST; N]` is stable
When `const_in_array_repeat_expressions` (RFC 2203) got unstably implemented as part of https://github.com/rust-lang/rust/pull/61749, accidentally, the special case of repeating a *constant* got stabilized immediately. That is why the following code works on stable:
```rust
const EMPTY: Vec<i32> = Vec::new();
pub const fn bar() -> [Vec<i32>; 2] {
[EMPTY; 2]
}
fn main() {
let x = bar();
}
```
In contrast, if we had written `[expr; 2]` for some expression that is not *literally* a constant but could be evaluated at compile-time (e.g. `(EMPTY,).0`), this would have failed.
We could take back this stabilization as it was clearly accidental. However, I propose we instead just officially accept this and stabilize a small subset of RFC 2203, while leaving the more complex case of general expressions that could be evaluated at compile-time unstable. Making that case work well is pretty much blocked on inline `const` expressions (to avoid relying too much on [implicit promotion](https://github.com/rust-lang/const-eval/blob/master/promotion.md)), so it could take a bit until it comes to full fruition. `[CONST; N]` is an uncontroversial subset of this feature that has no semantic ambiguities, does not rely on promotion, and basically provides the full expressive power of RFC 2203 but without the convenience (people have to define constants to repeat them, possibly using associated consts if generics are involved).
Well, I said "no semantic ambiguities", that is only almost true... the one point I am not sure about is `[CONST; 0]`. There are two possible behaviors here: either this is equivalent to `let x = CONST; [x; 0]`, or it is a NOP (if we argue that the constant is never actually instantiated). The difference between the two is that if `CONST` has a destructor, it should run in the former case (but currently doesn't, due to https://github.com/rust-lang/rust/issues/74836); but should not run if it is considered a NOP. For regular `[x; 0]` there seems to be consensus on running drop (there isn't really an alternative); any opinions for the `CONST` special case? Should this instantiate the const only to immediately run its destructors? That seems somewhat silly to me. After all, the `let`-expansion does *not* work in general, for `N > 1`.
Cc `@rust-lang/lang` `@rust-lang/wg-const-eval`
Cc https://github.com/rust-lang/rust/issues/49147
Ran the tidy check
Following the diagnostic guide better
Diagnostic generation is now relegated to its own function in the diagnostics module.
Added tests
Fixed the ui test
Fix pretty printing an AST representing `&(mut ident)`
The PR fixes a misguiding help diagnostic in the parser that I reported in #80186. I discovered that the parsers recovery and reporting logic was correct but the pretty printer produced wrong code for the example. (Details in https://github.com/rust-lang/rust/issues/80186#issuecomment-748498676)
Example:
```rust
#![allow(unused_variables)]
fn main() {
let mut &x = &0;
}
```
The AST fragment
`PatKind::Ref(PatKind::Ident(BindingMode::ByValue(Mutability::Mut), ..), Mutability::Not)`
was printed to be `&mut ident`. But this wouldn't round trip through parsing again, because then it would be:
`PatKind::Ref(PatKind::Ident(BindingMode::ByValue(Mutability::Not), ..), Mutability::Mut)`
Now the pretty-printer prints `&(mut ident)`. Reparsing that code results in the AST fragment
`PatKind::Ref(PatKind::Paren(PatKind::Ident(BindingMode::ByValue(Mutability::Mut), ..)), Mutability::Not)`
which I think should behave like the original pattern.
Old diagnostic:
```
error: `mut` must be attached to each individual binding
--> src/main.rs:3:9
|
3 | let mut &x = &0;
| ^^^^^^ help: add `mut` to each binding: `&mut x`
|
= note: `mut` may be followed by `variable` and `variable @ pattern`
```
New diagnostic:
```
error: `mut` must be attached to each individual binding
--> src/main.rs:3:9
|
3 | let mut &x = &0;
| ^^^^^^ help: add `mut` to each binding: `&(mut x)`
|
= note: `mut` may be followed by `variable` and `variable @ pattern`
```
Fixes#80186
Cleanup markdown span handling
1. Get rid of `locate()` in markdown handling
This function was unfortunate for several reasons:
- It used `unsafe` because it wanted to tell whether a string came from
the same *allocation* as another, not just whether it was a textual match.
- It recalculated spans even though they were already available from pulldown
- It sometimes *failed* to calculate the span, which meant it was always possible for the span to be `None`, even though in practice that should never happen.
This has several cleanups:
- Make the span required
- Pass through the span from pulldown in the `HeadingLinks` and `Footnotes` iterators
- Only add iterator bounds on the `impl Iterator`, not on `new` and the struct itself.
2. Remove unnecessary scope in `markdown_links`
I recommend reading a single commit at a time.
cc ``@bugadani`` - this will conflict with https://github.com/rust-lang/rust/pull/77859, I'll try to make sure that gets merged first.
Handle desugaring in impl trait bound suggestion
Fixes#79843.
When an associated type of a generic function parameter needs extra bounds, the diagnostics may suggest replacing an `impl Trait` with a named type parameter so that it can be referenced in the where clause. On stable and nightly, the suggestion can be malformed, for instance transforming:
```rust
async fn run(_: &(), foo: impl Foo) -> std::io::Result<()>
```
Into:
```rust
async fn run(_: &, F: Foo(), foo: F) -> std::io::Result<()> where <F as Foo>::Bar: Send
^^^^^^^^ ^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
Where we want something like:
```rust
async fn run<F: Foo>(_: &(), foo: F) -> std::io::Result<()> where <F as Foo>::Bar: Send
^^^^^^^^ ^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
The problem is that the elided lifetime of `&()` is added as a generic parameter when desugaring the async fn; the suggestion code sees this as an existing generic parameter and tries to use its span as an anchor to inject `F` into the parameter list. There doesn't seem to be an entirely principled way to check which generic parameters in the HIR were explicitly named in the source, so this commit changes the heuristics when generating the suggestion to only consider type parameters whose spans are contained within the span of the `Generics` when determining how to insert an additional type parameter into the declaration. (And to be safe it also excludes parameters whose spans are marked as originating from desugaring, although that doesn't seem to handle this elided lifetime.)
When normalizing a projection which results in a cycle, we would
cache the result of `project_type` without the nested obligations
(because they're not needed for inference). This would result in
the nested obligations only being handled once in fulfill, which
would avoid the cycle error.
Fixes#79714, a regresion from #79305 caused by the removal of
`get_paranoid_cache_value_obligation`.
This function was unfortunate for several reasons:
- It used `unsafe` because it wanted to tell whether a string came from
the same *allocation* as another, not just whether it was a textual
match.
- It recalculated spans even though they were already available from
pulldown
- It sometimes *failed* to calculate the span, which meant it was always
possible for the span to be `None`, even though in practice that
should never happen.
This commit has several cleanups:
- Make the span required
- Pass through the span from pulldown in the `HeadingLinks` and
`Footnotes` iterators
- Only add iterator bounds on the `impl Iterator`, not on `new` and the
struct itself.
Turn quadratic time on number of impl blocks into linear time
Previously, if you had a lot of inherent impl blocks on a type like:
```Rust
struct Foo;
impl Foo { fn foo_1() {} }
// ...
impl Foo { fn foo_100_000() {} }
```
The compiler would be very slow at processing it, because
an internal algorithm would run in O(n^2), where n is the number
of impl blocks. Now, we add a new algorithm that allocates but
is faster asymptotically.
Comparing rustc nightly with a local build of rustc as of this PR (results in seconds):
| N | real time before | real time after |
| - | - | - |
| 4_000 | 0.57 | 0.46 |
| 8_000 | 1.31 | 0.84 |
| 16_000 | 3.56 | 1.69 |
| 32_000 | 10.60 | 3.73 |
I've tuned up the numbers to make the effect larger than the startup noise of rustc, but the asymptotic difference should hold for smaller n as well.
Note: current state of the PR omits error messages if there are other errors present already. For now, I'm mainly interested in a perf run to study whether this issue is present at all. Please queue one for this PR. Thanks!
Mark `-1` as an available niche for file descriptors
Based on discussion from <https://internals.rust-lang.org/t/can-the-standard-library-shrink-option-file/12768>, the file descriptor `-1` is chosen based on the POSIX API designs that use it as a sentinel to report errors. A bigger niche could've been chosen, particularly on Linux, but would not necessarily be portable.
This PR also adds a test case to ensure that the -1 niche (which is kind of hacky and has no obvious test case) works correctly. It requires the "upper" bound, which is actually -1, to be expressed in two's complement.
Skip `dsymutil` by default for compiler bootstrap
`dsymutil` adds time to builds on Apple platforms for no clear benefit, and also makes it more difficult for debuggers to find debug info (which `@pnkfelix` highlighted on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/does.20lldb.20%28or.20gdb%29.20work.20on.20rustc.20on.20Mac.3F/near/220482092)). The compiler currently defaults to running `dsymutil` to preserve its historical default, but when compiling the compiler itself, we skip it by default since we know it's safe to do so in that case.
r? `@nagisa`
`PatKind::Ref(PatKind::Ident(BindingMode::ByValue(Mutability::Mut), ..), ..)`
is an AST representing `&(mut ident)`. It was errorneously printed as
`&mut ident` which reparsed into a syntactically different AST.
This affected help diagnostics in the parser.
Make BoundRegion have a kind of BoungRegionKind
Split from #76814
Also includes making `replace_escaping_bound_vars` only return `T`
Going to r? `@lcnr`
Feel free to reassign
or_patterns: implement :pat edition-specific behavior
cc #54883 `@joshtriplett`
This PR implements the edition-specific behavior of `:pat` wrt or-patterns, as determined by the crater runs and T-lang consensus in https://github.com/rust-lang/rust/issues/54883#issuecomment-745509090.
I believe this can unblock stabilization of or_patterns.
r? `@petrochenkov`
`dsymutil` adds time to builds on Apple platforms for no clear benefit, and also
makes it more difficult for debuggers to find debug info. The compiler currently
defaults to running `dsymutil` to preserve its historical default, but when
compiling the compiler itself, we skip it by default since we know it's safe to
do so in that case.
const_evaluatable_checked: fix occurs check
fixes#79615
this is kind of a hack because we use `TypeRelation` for both the `Generalizer` and the `ConstInferUnifier` but i am not sure if there is a useful way to disentangle this without unnecessarily duplicating some code.
The error in the added test is kind of unavoidable until we erase the unused substs of `ConstKind::Unevaluated`. We talked a bit about this in the cg lazy norm meeting (https://rust-lang.zulipchat.com/#narrow/stream/260443-project-const-generics/topic/lazy_normalization_consts)
Improve and fix diagnostics of exhaustiveness checking
Primarily, this fixes https://github.com/rust-lang/rust/issues/56379. This also fixes incorrect interactions between or-patterns and slice patterns that I discovered while working on #56379. Those two examples show the incorrect diagnostics:
```rust
match &[][..] {
[true] => {}
[true // detected as unreachable but that's not true
| false, ..] => {}
_ => {}
}
match (true, None) {
(true, Some(_)) => {}
(false, Some(true)) => {}
(true | false, None | Some(true // should be detected as unreachable
| false)) => {}
}
```
I did not measure any perf impact. However, I suspect that [`616ba9f`](616ba9f9f7) should have a negative impact on large or-patterns. I'll see what the perf run says; I have optimization ideas up my sleeve if needed.
EDIT: I initially had a noticeable perf impact that I thought unavoidable. I then proceeded to avoid it x)
r? `@varkor`
`@rustbot` label +A-exhaustiveness-checking
passes: prohibit invalid attrs on generic params
Fixes#78957.
This PR modifies the `check_attr` pass so that attribute placement on generic parameters is checked for validity.
r? `@lcnr`
Continue String to Symbol conversion in rustdoc (2)
Follow-up of #80119.
This is the last one (and I actually expected more conversions but seems like it was the last one remaining...).
r? `@jyn514`
Continue String to Symbol conversion in rustdoc
Follow-up of https://github.com/rust-lang/rust/pull/80091.
This PR is already big enough so I'll stop here before the next one.
r? `@jyn514`
Rollup of 5 pull requests
Successful merges:
- #78164 (Prefer regions with an `external_name` in `approx_universal_upper_bound`)
- #80003 (Fix overflow when converting ZST Vec to VecDeque)
- #80023 (Enhance error message when misspelled label to value in break expression)
- #80046 (Add more documentation to `Diagnostic` and `DiagnosticBuilder`)
- #80109 (Remove redundant and unreliable coverage test results)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Remove redundant and unreliable coverage test results
The `coverage-reports` tests still generate counters and JSON reports
for inspection, but these files are no longer used in Makefile diffs, to
reduce complexity and confusion from unreliable or unexpected test
results, especially when maintaining them (i.e., generating `--bless`ed
results).
The associated `expected_` files for counters and JSON reports have been
removed, leaving only the files actually used for testing: the `llvm-cov
show` reports.
r? `@tmandry`
Tyler - as we discussed offline...
FYI: `@wesleywiser` `@Swatinem`
Arpad, depending on the timing of this PR, it may not affect you, but I'm removing some of the files that produce slightly different results on Windows as they really aren't necessary to validate coverage results.
Prefer regions with an `external_name` in `approx_universal_upper_bound`
Fixes#75785
When displaying a MIR borrowcheck error, we may need to find an upper
bound for a region, which gives us a region to point to in the error
message. However, a region might outlive multiple distinct universal
regions, in which case the only upper bound is 'static
To try to display a meaningful error message, we compute an
'approximate' upper bound by picking one of the universal regions.
Currently, we pick the region with the lowest index - however, this
caused us to produce a suboptimal error message in issue #75785
This PR `approx_universal_upper_bound` to prefer regions with an
`external_name`. This causes us to prefer regions from function
arguments/upvars, which seems to lead to a nicer error message in some
cases.
Fixes#75785
When displaying a MIR borrowcheck error, we may need to find an upper
bound for a region, which gives us a region to point to in the error
message. However, a region might outlive multiple distinct universal
regions, in which case the only upper bound is 'static
To try to display a meaningful error message, we compute an
'approximate' upper bound by picking one of the universal regions.
Currently, we pick the region with the lowest index - however, this
caused us to produce a suboptimal error message in issue #75785
This PR `approx_universal_upper_bound` to prefer regions with an
`external_name`. This causes us to prefer regions from function
arguments/upvars, which seems to lead to a nicer error message in some
cases.
Move binder for dyn to each list item
This essentially changes `ty::Binder<&'tcx List<ExistentialTraitRef>>` to `&'tcx List<ty::Binder<ExistentialTraitRef>>`.
This is a first step in moving the `dyn Trait` representation closer to Chalk, which we've talked about in `@rust-lang/wg-traits.`
r? `@nikomatsakis`
bootstrap: update ci-llvm stamp after #80087Fixes#80086.
Unfortunately, #80087 forgot to update the ci-llvm stamp, so the updated ci-llvm tarball with `llvm-dwp` wasn't downloaded by users. This PR updates the ci-llvm stamp to resolve that problem.
r? `@Mark-Simulacrum`
Use more symbols in rustdoc
Builds on https://github.com/rust-lang/rust/pull/80044 and should not be merged before.
I want to test if this is actually faster before merging it, there was a lot of `to_string()` calls so I'm not sure it will actually help. That means I have to wait for 80044 to get merged before running perf.
r? `@ghost`
Always run intrinsics lowering pass
Move intrinsics lowering pass from the optimization phase (where it
would not run if -Zmir-opt-level=0), to the drop lowering phase where it
runs unconditionally.
The implementation of those intrinsics in code generation and
interpreter is unnecessary. Remove it.
Unfortunately, #80087 forgot to update the ci-llvm stamp, so the updated
ci-llvm tarball with `llvm-dwp` wasn't downloaded by users. This commit
updates the ci-llvm stamp to resolve that problem.
Signed-off-by: David Wood <david@davidtw.co>
The `coverage-reports` tests still generate counters and JSON reports
for inspection, but these files are no longer used in Makefile diffs, to
reduce complexity and confusion from unreliable or unexpected test
results, especially when maintaining them (i.e., generating `--bless`ed
results).
The associated `expected_` files for counters and JSON reports have been
removed, leaving only the files actually used for testing: the `llvm-cov
show` reports.
Fixed conflict with drop elaboration and coverage
See
https://github.com/rust-lang/rust/issues/80045#issuecomment-745733339
Coverage statements are moved to the beginning of the BCB. This does
also affect what's counted before a panic, changing some results, but I
think these results may even be preferred? In any case, there are no
guarantees about what's counted when a panic occurs (by design).
r? `@tmandry`
FYI `@wesleywiser` `@ecstatic-morse`
Fix issue #78496
EarlyOtherwiseBranch finds MIR structures like:
```
bb0: {
...
_2 = discriminant(X)
...
switchInt(_2) -> [1_isize: bb1, otherwise: bb3]
}
bb1: {
...
_3 = discriminant(Y)
...
switchInt(_3) -> [1_isize: bb2, otherwise: bb3]
}
bb2: {...}
bb3: {...}
```
And transforms them into something like:
```
bb0: {
...
_2 = discriminant(X)
_3 = discriminant(Y)
_4 = Eq(_2, _3)
switchInt(_4) -> [true: bb4, otherwise: bb3]
}
bb2: {...} // unchanged
bb3: {...} // unchanged
bb4: {
switchInt(_2) -> [1_isize: bb2, otherwise: bb3]
}
```
But that is not always a safe thing to do -- sometimes the early `otherwise` branch is necessary so the later block could assume the value of `discriminant(X)`.
I am not totally sure what's the best way to detect that, but fixing #78496 should be easy -- we just check if `X` is a sub-expression of `Y`. A more precise test might be to check if `Y` contains a `Downcast(1)` of `X`, but I think this might be good enough.
Fix#78496
Allow `since="TBD"` for rustc_deprecated
Closes#78381.
This PR only affects `#[rustc_deprecated]`, not `#[deprecated]`, so there is no effect on any stable language feature.
Likewise this PR only implements `since="TBD"`, it does not actually tag any library functions with it, so there is no effect on any stable API.
Overview of changes:
* `rustc_middle/stability.rs`:
* change `deprecation_in_effect` function to return `false` when `since="TBD"`
* tidy up the compiler output when a deprecated item has `since="TBD"`
* `rustc_passes/stability.rs`:
* allow `since="TBD"` to pass the sanity check for stable_version < deprecated_version
* refactor the "invalid stability version" and "invalid deprecation version" error into separate errors
* rustdoc: make `since="TBD"` message on a deprecated item's page match the command-line deprecation output
* tests:
* test rustdoc output
* test that the `deprecated_in_future` lint fires when `since="TBD"`
* test the new "invalid deprecation version" error message
Implement if-let match guards
Implements rust-lang/rfcs#2294 (tracking issue: #51114).
I probably should do a few more things before this can be merged:
- [x] Add tests (added basic tests, more advanced tests could be done in the future?)
- [x] Add lint for exhaustive if-let guard (comparable to normal if-let statements)
- [x] Fix clippy
However since this is a nightly feature maybe it's fine to land this and do those steps in follow-up PRs.
Thanks a lot `@matthewjasper` ❤️ for helping me with lowering to MIR! Would you be interested in reviewing this?
r? `@ghost` for now
Take into account negative impls in "trait item not found" suggestions
This removes the suggestion to implement a trait for a type when that type already has a negative implementation for the trait, and replaces it with a note to point out that the trait is explicitely unimplemented, as suggested by `@scottmcm.`
Helps with #79683.
r? `@scottmcm` do you want to review this?
This commit includes the `llvm-dwp` tool in the CI LLVM (which rustc
developers can download instead of building LLVM locally) - `llvm-dwp`
is required by Split DWARF which landed in PR #77117.
Signed-off-by: David Wood <david@davidtw.co>
cg_llvm: split dwarf support
cc #34651
This PR adds initial support for Split DWARF to rustc, based on the implementation in Clang.
##### Current Status
This PR currently has functioning split-dwarf, running rustc with `-Zsplit-dwarf=split` when compiling a binary will produce a `dwp` alongside the binary, which contains the linked dwarf objects.
```shell-session
$ rustc -Cdebuginfo=2 -Zsplit-dwarf=split -C save-temps ./foo.rs
$ ls foo*
foo
foo.belfx9afw9cmv8.rcgu.dwo
foo.belfx9afw9cmv8.rcgu.o
foo.foo.7rcbfp3g-cgu.0.rcgu.dwo
foo.foo.7rcbfp3g-cgu.0.rcgu.o
foo.foo.7rcbfp3g-cgu.1.rcgu.dwo
foo.foo.7rcbfp3g-cgu.1.rcgu.o
foo.foo.7rcbfp3g-cgu.2.rcgu.dwo
foo.foo.7rcbfp3g-cgu.2.rcgu.o
foo.foo.7rcbfp3g-cgu.3.rcgu.dwo
foo.foo.7rcbfp3g-cgu.3.rcgu.o
foo.foo.7rcbfp3g-cgu.4.rcgu.dwo
foo.foo.7rcbfp3g-cgu.4.rcgu.o
foo.foo.7rcbfp3g-cgu.5.rcgu.dwo
foo.foo.7rcbfp3g-cgu.5.rcgu.o
foo.foo.7rcbfp3g-cgu.6.rcgu.dwo
foo.foo.7rcbfp3g-cgu.6.rcgu.o
foo.foo.7rcbfp3g-cgu.7.rcgu.dwo
foo.foo.7rcbfp3g-cgu.7.rcgu.o
foo.dwp
foo.rs
$ readelf -wi foo.foo.7rcbfp3g-cgu.0.rcgu.o
# ...
Compilation Unit @ offset 0x90:
Length: 0x2c (32-bit)
Version: 4
Abbrev Offset: 0x5b
Pointer Size: 8
<0><9b>: Abbrev Number: 1 (DW_TAG_compile_unit)
<9c> DW_AT_stmt_list : 0xe8
<a0> DW_AT_comp_dir : (indirect string, offset: 0x13b): /home/david/Projects/rust/rust0
<a4> DW_AT_GNU_dwo_name: (indirect string, offset: 0x15b): foo.foo.7rcbfp3g-cgu.0.rcgu.dwo
<a8> DW_AT_GNU_dwo_id : 0x357472a2b032d7b9
<b0> DW_AT_low_pc : 0x0
<b8> DW_AT_ranges : 0x40
<bc> DW_AT_GNU_addr_base: 0x0
# ...
```
##### To-Do
I've opened this PR as a draft to get feedback and work out how we'd expect rustc to work when Split DWARF is requested. It might be easier to read the PR commit-by-commit.
- [ ] Add error when Split DWARF is requested on platforms where it doesn't make sense.
- [x] Determine whether or not there should be a single `dwo` output from rustc, or one per codegen-unit as exists currently.
- [x] Add tests.
- [x] Fix `single` mode - currently single mode doesn't change the invocation of `addPassesToEmitFile`, which is correct, but it also needs to change the split dwarf path provided to `createCompileUnit` and `createTargetMachine` so that it's just the final binary (currently it is still a non-existent `dwo` file).
r? `@nagisa`
cc `@michaelwoerister` `@eddyb` `@alexcrichton` `@rust-lang/wg-incr-comp`
This commit adds a Split DWARF compare mode to compiletest so that
debuginfo tests are also tested using Split DWARF in split mode (and
manually in single mode).
Signed-off-by: David Wood <david@davidtw.co>
`llvm-dwp` is required for linking the DWARF objects into DWARF packages
when using Split DWARF, especially given that rustc produces multiple
DWARF objects (one for each codegen unit).
Signed-off-by: David Wood <david@davidtw.co>
Don't look for blanket impls in intra-doc links
This never worked and has been causing severe performance problems.
Hopefully it will be re-landed at some point in the future when it
actually works, but in the meantime it makes no sense to have the code
around when it does nothing and actively makes rustdoc harder to use.
Closes https://github.com/rust-lang/rust/issues/78761. Does *not* affect https://github.com/rust-lang/rust/issues/78800.
r? `@Manishearth`
cc `@seeplusplus`
See
https://github.com/rust-lang/rust/issues/80045#issuecomment-745733339
Coverage statements are moved to the beginning of the BCB. This does
also affect what's counted before a panic, changing some results, but I
think these results may even be preferred? In any case, there are no
guarantees about what's counted when a panic occurs (by design).
This never worked and has been causing severe performance problems.
Hopefully it will be re-landed at some point in the future when it
actually works, but in the meantime it makes no sense to have the code
around when it does nothing and actively makes rustdoc harder to use.
make MIR graphviz generation use gsgdt
gsgdt [https://crates.io/crates/gsgdt] is a crate which provides an
interface for stringly typed graphs. It also provides generation of
graphviz dot format from said graph.
This is the first in a series of PRs on moving graphviz code out of rustc into normal crates and then implementating graph diffing on top of these crates.
r? `@oli-obk`
[rustdoc] Switch to Symbol for item.name
This decreases the size of `Item` from 680 to 616 bytes. It also does a
lot less work since it no longer has to copy as much.
Helps with #79103.
r? `@GuillaumeGomez`
Fixes reported bugs in Rust Coverage
Fixes: #79569Fixes: #79566Fixes: #79565
For the first issue (#79569), I got hit a `debug_assert!()` before
encountering the reported error message (because I have `debug = true`
enabled in my config.toml).
The assertion showed me that some `SwitchInt`s can have more than one
target pointing to the same `BasicBlock`.
I had thought that was invalid, but since it seems to be possible, I'm
allowing this now.
I added a new test for this.
----
In the last two cases above, both tests (intentionally) fail to compile,
but the `InstrumentCoverage` pass is invoked anyway.
The MIR starts with an `Unreachable` `BasicBlock`, which I hadn't
encountered before. (I had assumed the `InstrumentCoverage` pass
would only be invoked with MIRs from successful compilations.)
I don't have test infrastructure set up to test coverage on files that
fail to compile, so I didn't add a new test.
r? `@tmandry`
FYI: `@wesleywiser`
consider assignments of union field of ManuallyDrop type safe
Assigning to `Copy` union fields is safe because that assignment will never drop anything. However, with https://github.com/rust-lang/rust/pull/77547, unions may also have `ManuallyDrop` fields, and their assignments are currently still unsafe. That seems unnecessary though, as assigning `ManuallyDrop` does not drop anything either, and is thus safe even for union fields.
I assume this will at least require FCP.
[mir-opt] Allow debuginfo to be generated for a constant or a Place
Prior to this commit, debuginfo was always generated by mapping a name
to a Place. This has the side-effect that `SimplifyLocals` cannot remove
locals that are only used for debuginfo because their other uses have
been const-propagated.
To allow these locals to be removed, we now allow debuginfo to point to
a constant value. The `ConstProp` pass detects when debuginfo points to
a local with a known constant value and replaces it with the value. This
allows the later `SimplifyLocals` pass to remove the local.
This was always questionable, and removing it doesn't fail any tests, so
I think this was not affecting the behavior. It dates all the way back
to the very first commit of rustdoc: 268f3f0ff5
Move intrinsics lowering pass from the optimization phase (where it
would not run if -Zmir-opt-level=0), to the drop lowering phase where it
runs unconditionally.
The implementation of those intrinsics in code generation and
interpreter is unnecessary. Remove it.
Adds checks for:
* `no_core` attribute
* explicitly-enabled `legacy` symbol mangling
* mir_opt_level > 1 (which enables inlining)
I removed code from the `Inline` MIR pass that forcibly disabled
inlining if `-Zinstrument-coverage` was set. The default `mir_opt_level`
does not enable inlining anyway. But if the level is explicitly set and
is greater than 1, I issue a warning.
The new warnings show up in tests, which is much better for diagnosing
potential option conflicts in these cases.
Properly capture trailing 'unglued' token
If we try to capture the `Vec<u8>` in `Option<Vec<u8>>`, we'll
need to capture a `>` token which was 'unglued' from a `>>` token.
The processing of unglueing a token for parsing purposes bypasses the
usual capturing infrastructure, so we currently lose the trailing `>`.
As a result, we fall back to the reparsed `TokenStream`, causing us to
lose spans.
This commit makes token capturing keep track of a trailing 'unglued'
token. Note that we don't need to care about unglueing except at the end
of the captured tokens - if we capture both the first and second unglued
tokens, then we'll end up capturing the full 'glued' token, which
already works correctly.
Recover on `const impl<> X for Y`
`@leonardo-m` mentioned that `const impl Foo for Bar` could be recovered from in #79287.
I'm not sure about the error strings as they are, I think it should probably be something like the error that `expected_one_of_not_found` makes + the suggestion to flip the keywords, but I'm not sure how exactly to do that. Also, I decided not to try to handle `const unsafe impl` or `unsafe const impl` cause I figured that `unsafe impl const` would be pretty rare anyway (if it's even valid?), and it wouldn't be worth making the code more messy.
Resolve enum field visibility correctly
Fixes#79593. 🎉
Previously, this code treated enum fields' visibility as if they were
struct fields. However, that's not correct because the visibility of a
struct field with `ast::VisibilityKind::Inherited` is private to the
module it's defined in, whereas the visibility of an *enum* field with
`ast::VisibilityKind::Inherited` is the visibility of the enum it
belongs to.
Fixes submit event of the search input
Fixes https://github.com/rust-lang/rust/issues/79960
It's a very funny corner case:
In HTML, when a button follows an input (in a `form`), if the enter keep is pressed on the input, instead of sending the submit event to the input, it'll create a click event on the button following it, which in this case made the help popup show up whenever "enter" was pressed.
cc `@camelid`
r? `@jyn514`
rustdoc light theme: Fix CSS for selected buttons
Fixes#79961.
The background was dark before, which made the text impossible to read.
Now the button doesn't override the background, and the only thing it
does is add a light-blue top border.
Ultimately, the search results tabs now look very similar to how they
used to look.
r? `@GuillaumeGomez`
fix more clippy::complexity findings
fix clippy::unnecessary_filter_map
use if let Some(x) = .. instead of ...map(|x|) to conditionally run fns that return () (clippy::option_map_unit_fn)
fix clippy::{needless_bool, manual_unwrap_or}
don't clone types that are copy (clippy::clone_on_copy)
don't convert types into identical types with .into() (clippy::useless_conversion)
use strip_prefix over slicing (clippy::manual_strip)
r? ``@Dylan-DPC``
Fix rustup support in default_build_triple for python3
bootstrap completely ignores all errors when detecting a rustup version,
so this wasn't noticed before.
Fixes the following error:
```
rustup not detected: a bytes-like object is required, not 'str'
falling back to auto-detect
```
This also takes the opportunity to only call rustup and other external
commands only once during startup.
Follow-up to https://github.com/rust-lang/rust/pull/78513.
In HTML, when a button follows an input, if the enter keep is pressed on the input, instead of sending the submit event to the input, it'll create a click event on the button following it, which in this case made the help popup show up whenever "enter" was pressed.
Previously, this code treated enum fields' visibility as if they were
struct fields. However, that's not correct because the visibility of a
struct field with `ast::VisibilityKind::Inherited` is private to the
module it's defined in, whereas the visibility of an *enum* field with
`ast::VisibilityKind::Inherited` is the visibility of the enum it
belongs to.
If we try to capture the `Vec<u8>` in `Option<Vec<u8>>`, we'll
need to capture a `>` token which was 'unglued' from a `>>` token.
The processing of unglueing a token for parsing purposes bypasses the
usual capturing infrastructure, so we currently lose the trailing `>`.
As a result, we fall back to the reparsed `TokenStream`, causing us to
lose spans.
This commit makes token capturing keep track of a trailing 'unglued'
token. Note that we don't need to care about unglueing except at the end
of the captured tokens - if we capture both the first and second unglued
tokens, then we'll end up capturing the full 'glued' token, which
already works correctly.
The background was dark before, which made the text impossible to read.
Now the background is white, which is how selected `div`s are rendered.
As a result, the search results tabs now look identical to how they
used to look (before #79896).
[rustdoc] Calculate span information on demand instead of storing it ahead of time
This brings `size_of<clean::types::Span>()` down from over 100 bytes (!!) to only 12, the same as rustc. It brings `Item` down even more, from `784` to `680`.
~~TODO: I need to figure out how to do this for the JSON backend too. That uses `From` impls everywhere, which don't allow passing in the `Session` as an argument. `@P1n3appl3,` `@tmandry,` maybe one of you have ideas?~~ Figured it out, fortunately only two functions needed to be changed. I like the `convert_x()` format better than `From` everywhere but I'm open to feedback.
Helps with #79103
Fixes: #79569Fixes: #79566Fixes: #79565
For the first issue (#79569), I got hit a `debug_assert!()` before
encountering the reported error message (because I have `debug = true`
enabled in my config.toml).
The assertion showed me that some `SwitchInt`s can have more than one
target pointing to the same `BasicBlock`.
I had thought that was invalid, but since it seems to be possible, I'm
allowing this now.
I added a new test for this.
----
In the last two cases above, both tests (intentionally) fail to compile,
but the `InstrumentCoverage` pass is invoked anyway.
The MIR starts with an `Unreachable` `BasicBlock`, which I hadn't
encountered before. (I had assumed the `InstrumentCoverage` pass
would only be invoked with MIRs from successful compilations.)
I don't have test infrastructure set up to test coverage on files that
fail to compile, so I didn't add a new test.
Capture precise paths in THIR and MIR
This PR allows THIR and MIR to use the result of the new capture analysis to actually capture precise paths
To achieve we:
- Writeback min capture results to TypeckResults
- Move handling upvars to PlaceBuilder in mir_build
- Lower precise paths in THIR build by reading min_captures
- Search for ancestors in min_capture when trying to build a MIR place which starts off of an upvar
Closes: https://github.com/rust-lang/project-rfc-2229/issues/10
Partly implements: rust-lang/project-rfc-2229#18
Work that remains (not in this PR):
- [ ] [Known bugs when feature gate is enabled](https://github.com/rust-lang/project-rfc-2229/projects/1?card_filter_query=label%3Abug)
- [ ] Use min_capure_map for
- [ ] Liveness analysis
- [ ] rustc_mir/interpret/validity.rs
- [ ] regionck
- [ ] rust-lang/project-rfc-2229#8
- [ ] remove closure_captures and upvar_capture_map
r? `@ghost`
Apply `doc(cfg)` from parent items while collecting trait impls
Because trait impls bypass the standard `clean` hierarchy they do not participate in the `propagate_doc_cfg` pass, so instead we need to pre-collect all possible `doc(cfg)` attributes that will apply to them when cleaning.
fixes#79201
CTFE: tweak abort-on-uninhabited message
Having an "aborted execution:" makes it more consistent with the `Abort` terminator saying "the program aborted execution". Right now, at least one of the two errors will look weird in Miri.
r? `@oli-obk`
Use `def_path_hash_to_def_id` when re-using a `RawDefId`
Fixes#79890
Previously, we just copied a `RawDefId` from the 'old' map to the 'new'
map. However, the `RawDefId` for a given `DefPathHash` may be different
in the current compilation session. Using `def_path_hash_to_def_id`
ensures that the `RawDefId` we use is valid in the current session.
Make search results tab and help button focusable with keyboard
Fixes https://github.com/rust-lang/rust/issues/79859.
I replaced the element with `button` tag, which allows to focus them (and "click" on them using "enter") using only the keyboard.
cc ``@sersorrel``
r? ``@Manishearth``
Clarify the 'default is only allowed on...' error
Code like
impl Foo {
default fn foo() {}
}
will trigger the error
error: `default` is only allowed on items in `impl` definitions
--> src/lib.rs:5:5
|
5 | default fn foo() {}
| -------^^^^^^^^^
| |
| `default` because of this
but that's very confusing! I *did* put it on an item in an impl!
So this commit changes the message to
error: `default` is only allowed on items in trait impls
--> src/lib.rs:5:5
|
5 | default fn foo() {}
| -------^^^^^^^^^
| |
| `default` because of this
Dogfood `str_split_once()`
Part of https://github.com/rust-lang/rust/issues/74773.
Beyond increased clarity, this fixes some instances of a common confusion with how `splitn(2)` behaves: the first element will always be `Some()`, regardless of the delimiter, and even if the value is empty.
Given this code:
```rust
fn main() {
let val = "...";
let mut iter = val.splitn(2, '=');
println!("Input: {:?}, first: {:?}, second: {:?}", val, iter.next(), iter.next());
}
```
We get:
```
Input: "no_delimiter", first: Some("no_delimiter"), second: None
Input: "k=v", first: Some("k"), second: Some("v")
Input: "=", first: Some(""), second: Some("")
```
Using `str_split_once()` makes more clear what happens when the delimiter is not found.
Fixes#79890
Previously, we just copied a `RawDefId` from the 'old' map to the 'new'
map. However, the `RawDefId` for a given `DefPathHash` may be different
in the current compilation session. Using `def_path_hash_to_def_id`
ensures that the `RawDefId` we use is valid in the current session.
Based on discussion from https://internals.rust-lang.org/t/can-the-standard-library-shrink-option-file/12768,
the file descriptor -1 is chosen based on the POSIX API designs that use it as a sentinel to report errors.
A bigger niche could've been chosen, particularly on Linux, but would not necessarily be portable.
This PR also adds a test case to ensure that the -1 niche
(which is kind of hacky and has no obvious test case) works correctly.
It requires the "upper" bound, which is actually -1, to be expressed in two's complement.
ci: use 20.04 on x86_64-gnu-nopt builder
Switch the `x86_64-gnu-nopt` builder to use Ubuntu 20.04.
Ubuntu 20.04 has a more recent gdb version than Ubuntu 16.04 (9.1 vs 7.11.1), which is required for rust-lang/rust#77177, as 16.04's gdb 7.11.1 crashes in some cases with Split DWARF. `x86_64-gnu-nopt` is chosen because it runs compare modes, which is how Split DWARF testing is implemented in rust-lang/rust#77177.
I've not confirmed that the issue is resolved with gdb 9.1 (Feb 2020), but system was using gdb 9.2 (May 2020) and that was fine and it seems more likely to me that the bug was resolved between gdb 7.11.1 (May 2016) and gdb 9.1.
Updating a builder to use 20.04 was suggested by `@Mark-Simulacrum` in https://github.com/rust-lang/rust/pull/77117#issuecomment-731846170. I'm not sure if this is the only change that is required - if more are necessary then I'm happy to do that.
r? `@pietroalbini`
cc `@Mark-Simulacrum`
This commit switches the x86_64-gnu-nopt builder to use Ubuntu 20.04,
which contains a more recent gdb version than Ubuntu 16.04 (newer gdb
versions fix a bug that Split DWARF can trigger, see
rust-lang/rust#77177 for motivation). x86_64-gnu-nopt is chosen because
it runs compare modes, which is how Split DWARF testing is implemented
in rust-lang/rust#77177.
Signed-off-by: David Wood <david@davidtw.co>
rustc_codegen_ssa: use bitcasts instead of type punning for scalar transmutes.
This specifically helps with `f32` <-> `u32` (`from_bits`, `to_bits`) in Rust-GPU (`rustc_codegen_spirv`), where (AFAIK) we don't yet have enough infrastructure to turn type punning memory accesses into SSA bitcasts.
(There may be more instances, but the one I've seen myself is `f32::signum` from `num-traits` inspecting e.g. the sign bit)
Sadly I've had to make an exception for `transmute`s between pointers and non-pointers, as LLVM disallows using `bitcast` for them.
r? `@nagisa` cc `@khyperia`
Constier maybe uninit
I was playing around trying to make `[T; N]::zip()` in #79451 be `const fn`. One of the things I bumped into was `MaybeUninit::assume_init`. Is there any reason for the intrinsic `assert_inhabited<T>()` and therefore `MaybeUninit::assume_init` not being `const`?
---
I have as best as I could tried to follow the instruction in [library/core/src/intrinsics.rs](https://github.com/rust-lang/rust/blob/master/library/core/src/intrinsics.rs#L11). I have no idea what I am doing but it seems to compile after some slight changes after the copy paste. Is this anywhere near how this should be done?
Also any ideas for name of the feature gate? I guess `const_maybe_assume_init` is quite misleading since I have added some more methods. Should I add test? If so what should be tested?
Remove tab-lock and replace it with ctrl+up/down arrows to switch between search result tabs
Fixes https://github.com/rust-lang/rust/issues/65212
What took the longest time was to update the help popup in the end.
r? `@Manishearth`
