Auto merge of #76708 - Mark-Simulacrum:lld-macos, r=alexcrichton
Always try to promote shared LLVM to the sysroot
Even when LLVM is not generally participating in a shared link with rustc, we
will likely still link to the shared dylib from rust-lld, so we still need to
promote it.
This reverts part of #76349; my expectation that the link-shared rule was sufficient was likely wrong.
Mark Rousskov [Mon, 14 Sep 2020 20:22:56 +0000 (16:22 -0400)]
Enable shared linking to LLVM on non-Windows
Windows doesn't quite support dynamic linking to LLVM yet, but on other
platforms we do. In #76708, it was discovered that we dynamically link to LLVM
from the LLVM tools (e.g., rust-lld), so we need the shared LLVM library to link
against. That means that if we do not have a shared link to LLVM, and want LLVM
tools to work, we'd be shipping two copies of LLVM on all of these platforms:
one in librustc_driver and one in libLLVM.
Also introduce an error into rustbuild if we do end up configured for shared
linking on Windows.
Auto merge of #76311 - lzutao:split_core-slice, r=lcnr
Split `core::slice` to smaller mods
Unfortunately the `#[lang = "slice"]` is too big (3003 lines), I cannot split it further.
Note for reviewer:
* I split to multiple commits for easier reviewing, but I could git squash them all to one if requested.
* Recommend pulling this change locally and using advanced git diff viewer or this command:
```
git show --reverse --color-moved=dimmed-zebra master..
```
---
I split core/slice/mod.rs to these modules:
* `ascii`: For operations on `[u8]`.
* `cmp`: For comparison operations on `[T]`, like PartialEq and SliceContains impl.
* `index`: For indexing operations like Index/IndexMut and SliceIndex.
* `iter`: For Iterator definitions and implementation on `[T]`.
- `macros`: For iterator! and forward_iterator! macros.
* `raw`: For free function to create `&[T]` or `&mut [T]` from pointer + length or a reference.
The heapsort wrapper in mod.rs is removed in favor of reexport from `sort::heapsort`.
Auto merge of #76684 - jyn514:refactor-intra-links, r=manishearth
Refactor intra doc link code
I got tired of `fold_item` being 500 lines long.
This is best reviewed one commit at a time with whitespace changes hidden.
There are no logic changes other than the last commit making a parameter checked by the caller instead of the callee.
Auto merge of #76682 - richkadel:vec-take, r=Mark-Simulacrum
Optimize behavior of vec.split_off(0) (take all)
Optimization improvement to `split_off()` so the performance meets the
intuitively expected behavior when `at == 0`, avoiding the current behavior
of copying the entire vector.
The change honors documented behavior that the original vector's
"previous capacity unchanged".
This improvement better supports the pattern for building and flushing a
buffer of elements, such as the following:
```rust
let mut vec = Vec::new();
loop {
vec.push(something);
if condition_is_met {
process(vec.split_off(0));
}
}
```
`Option` wrapping is the first alternative I thought of, but is much
less obvious and more verbose:
```rust
let mut capacity = 1;
let mut vec: Option<Vec<Stuff>> = None;
loop {
vec.get_or_insert_with(|| Vec::with_capacity(capacity)).push(something);
if condition_is_met {
capacity = vec.capacity();
process(vec.take().unwrap());
}
}
```
Directly using `mem::replace()` (instead of calling`split_off()`) could work,
but `mem::replace()` is a more advanced tool for Rust developers, and in
this case, I believe developers would assume the standard library should
be sufficient for the purpose described here.
The benefit of the approach to this change is it does not change the
existing API contract, but improves the peformance of `split_off(0)` for
`Vec`, `String` (which delegates `split_off()` to `Vec`), and any other
existing use cases.
This change adds tests to validate the behavior of `split_off()` with
regard to capacity, as originally documented, and confirm that behavior
still holds, when `at == 0`.
The change is an implementation detail, and does not require a
documentation change, but documenting the new behavior as part of its
API contract may benefit future users.
(Let me know if I should make that documentation update.)
Note, for future consideration:
I think it would be helpful to introduce an additional method to `Vec`
(if not also to `String`):
This would make it more clear how `Vec` supports the pattern, and make
it easier to find, since the behavior is similar to other `take()`
methods in the Rust standard library.
Auto merge of #75608 - estebank:suggest-boxed-match-exprs, r=lcnr,varkor
More structured suggestions for boxed trait objects instead of impl Trait on non-coerceable tail expressions
When encountering a `match` or `if` as a tail expression where the
different arms do not have the same type *and* the return type of that
`fn` is an `impl Trait`, check whether those arms can implement `Trait`
and if so, suggest using boxed trait objects.
Use structured suggestion for `impl T` to `Box<dyn T>`.
Auto merge of #75740 - GuillaumeGomez:stabilize-doc-alias-feature, r=ollie27
Stabilize doc_alias feature
Fixes #50146.
This PR intend to stabilize the `doc_alias` feature. The last remaining bits were missing checks on the attribute usage and on its arguments. Both have been added so I think we can now move to the next step.
Mark Rousskov [Sun, 6 Sep 2020 23:38:26 +0000 (19:38 -0400)]
Make bootstrap build on stable
This is generally a good idea, and will help with being able to build bootstrap
without Python over time as it means we can "just" build with cargo +beta build
rather than needing the user to set environment variables. This is a minor step,
but a necessary one on that road.
Auto merge of #76549 - ehuss:lints-comments, r=wesleywiser
Auto-generate lint documentation.
This adds a tool which will generate the lint documentation in the rustc book automatically. This is motivated by keeping the documentation up-to-date, and consistently formatted. It also ensures the examples are correct and that they actually generate the expected lint. The lint groups table is also auto-generated. See https://github.com/rust-lang/compiler-team/issues/349 for the original proposal.
An outline of how this works:
- The `declare_lint!` macro now accepts a doc comment where the documentation is written. This is inspired by how clippy works.
- A new tool `src/tools/lint-docs` scrapes the documentation and adds it to the rustc book during the build.
- It runs each example and verifies its output and embeds the output in the book.
- It does a few formatting checks.
- It verifies that every lint is documented.
- Groups are collected from `rustc -W help`.
I updated the documentation for all the missing lints. I have also added an "Explanation" section to each lint providing a reason for the lint and suggestions on how to resolve it.
This can lead towards a future enhancement of possibly showing these docs via the `--explain` flag to make them easily accessible and discoverable.
This is quite a bad hack to fix #75486. There might be a better way to check if the self type depends on generic parameters, but I wasn't able to come up with one.
Auto merge of #76123 - tmiasko:inline-args-storage, r=wesleywiser
inliner: Emit storage markers for introduced arg temporaries
When introducing argument temporaries during inlining, emit storage
marker statements just before the assignment and in the beginning of
the return block.
This ensures that such temporaries will not be considered live across
yield points after inlining inside a generator.
Auto merge of #76656 - jonas-schievink:fewer-unstable-metadata-queries, r=lcnr
Don't query stability data when `staged_api` is off
This data only needs to be encoded when `#![feature(staged_api)]` or `-Zforce-unstable-if-unmarked` is on. Running these queries takes measurable time on large crates with many items, so skip it when the unstable flags have not been enabled.
Auto merge of #76678 - jonas-schievink:rollup-vzl9yhx, r=jonas-schievink
Rollup of 12 pull requests
Successful merges:
- #75559 (unions: test move behavior of non-Copy fields)
- #76441 (Note that parallel-compiler = true causes tests to fail)
- #76527 (Remove internal and unstable MaybeUninit::UNINIT.)
- #76629 (Simplify iter zip struct doc)
- #76640 (Simplify SyncOnceCell's `take` and `drop`.)
- #76646 (Add mailmap entry)
- #76651 (Remove Windows details from Unix and VmWorks symlink() docstrings)
- #76663 (Simplify iter chain struct doc)
- #76665 (slice::from_raw_parts: explicitly mention that data must be initialized)
- #76667 (Fix CI LLVM to work on NixOS out of the box)
- #76668 (Add visualization of rustc span in doc)
- #76677 (note that test_stable_pointers does not reflect a stable guarantee)
Optimization improvement to `split_off()` so the performance meets the
intuitively expected behavior when `at == 0`, avoiding the current
behavior of copying the entire vector.
The change honors documented behavior that the method leaves the
original vector's "previous capacity unchanged".
This improvement better supports the pattern for building and flushing a
buffer of elements, such as the following:
```rust
let mut vec = Vec::new();
loop {
vec.push(something);
if condition_is_met {
process(vec.split_off(0));
}
}
```
`Option` wrapping is the first alternative I thought of, but is much
less obvious and more verbose:
```rust
let mut capacity = 1;
let mut vec: Option<Vec<Stuff>> = None;
loop {
vec.get_or_insert_with(|| Vec::with_capacity(capacity)).push(something);
if condition_is_met {
capacity = vec.capacity();
process(vec.take().unwrap());
}
}
```
Directly applying `mem::replace()` could work, but `mem::` functions are
typically a last resort, when a developer is actively seeking better
performance than the standard library provides, for example.
The benefit of the approach to this change is it does not change the
existing API contract, but improves the peformance of `split_off(0)` for
`Vec`, `String` (which delegates `split_off()` to `Vec`), and any other
existing use cases.
This change adds tests to validate the behavior of `split_off()` with
regard to capacity, as originally documented, and confirm that behavior
still holds, when `at == 0`.
The change is an implementation detail, and does not require a
documentation change, but documenting the new behavior as part of its
API contract may benefit future users.
(Let me know if I should make that documentation update.)
Note, for future consideration:
I think it would be helpful to introduce an additional method to `Vec`
(if not also to `String`):
This would make it more clear how `Vec` supports the pattern, and make
it easier to find, since the behavior is similar to other `take()`
methods in the Rust standard library.
Joshua Nelson [Sun, 13 Sep 2020 21:15:40 +0000 (17:15 -0400)]
Require `module_id` param to `resolve` to be non-empty
Previously, `resolve` would immediately check that `module_id` was
non-empty and give an error if not. This had two downsides:
- It introduced `Option`s everywhere, even if the calling function knew
it had a valid module, and
- It checked the module on each namespace, which is unnecessary: it only
needed to be checked once.
This makes the caller responsible for checking the module exists, making
the code a lot simpler.
Auto merge of #76623 - slightlyoutofphase:master, r=jyn514
Use `is_unstable_const_fn` instead of `is_min_const_fn` in rustdoc where appropriate
This closes #76501. Specifically, it allows for nightly users with the `#![feature(const_fn)]` flag enabled to still have their `const fn` declarations documented as such, while retaining the desired behavior that rustdoc *not* document functions that have the `rustc_const_unstable` attribute as `const`.
Auto merge of #76598 - ad-anssi:diagnostic_errors_fix, r=estebank
Fixing memory exhaustion when formatting short code suggestion
Details can be found in issue #76597. This PR replaces substractions with `saturating_sub`'s to avoid usize wrapping leading to memory exhaustion when formatting short suggestion messages.
Auto merge of #76658 - Aaron1011:fix/encode-dummy-loc-span, r=lcnr
Properly encode spans with a dummy location and non-root `SyntaxContext`
Previously, we would throw away the `SyntaxContext` of any span with a
dummy location during metadata encoding. This commit makes metadata Span
encoding consistent with incr-cache Span encoding - an 'invalid span'
tag is only used when it doesn't lose any information.
Auto merge of #76588 - guswynn:debug_logging, r=jyn514,Mark-Simulacrum
Add a dedicated debug-logging option to config.toml
`@Mark-Simulacrum` and I were talking in zulip and we found that turning on debug/trace logging in rustc is fairly confusing, as it effectively depends on debug-assertions and is not documented as such. `@Mark-Simulacrum` mentioned that we should probably have a separate option for logging anyways.
this diff adds that, having the option follow debug-assertions (so everyone's existing config.toml should be fine) and if the option is false
to test I ran ./x.py test <something> twice, once with `debug-logging = false` and once with `debug-logging = true` and made sure i only saw trace's when it was true
Aaron Hill [Sun, 13 Sep 2020 03:26:17 +0000 (23:26 -0400)]
Properly encode spans with a dummy location and non-root `SyntaxContext`
Previously, we would throw away the `SyntaxContext` of any span with a
dummy location during metadata encoding. This commit makes metadata Span
encoding consistent with incr-cache Span encoding - an 'invalid span'
tag is only used when it doesn't lose any information.
Auto merge of #76349 - Mark-Simulacrum:dl-llvm, r=alexcrichton
Download LLVM from CI to bootstrap (linux-only to start)
This follows #76332, adding support for using CI-built LLVM rather than building it locally. This should essentially "just work," but is left off by default in this PR.
While we can support downloading LLVM for multiple host triples, this currently only downloads it for the build triple. That said, it should be possible to expand this relatively easily should multiple host triples be desired. Most people shouldn't be adjusting host/target triples though, so this should cover most use cases.
Currently this downloads LLVM for the last bors-authored commit in the `git log`. This is a bit suboptimal -- we want the last bors-authored commit that touched the llvm-project submodule in basically all cases. But for now this just adds an extra ~20 MB download when rebasing atop latest master. Once we have a submodule bump landing after #76332, we can fix this behavior to reduce downloads further.
Auto merge of #76306 - tmiasko:nrvo-debuginfo, r=ecstatic-morse
NRVO: Allow occurrences of the return place in var debug info
The non-use occurrence of the return place in var debug info does not
currently inhibit NRVO optimization, but it will fail assertion in
`visit_place` when optimization is performed.
Relax assertion check to allow the return place in var debug info.
This case might be impossible to hit in optimization pipelines as of
now, but can be encountered in customized mir-opt-level=2 pipeline with
copy propagation disabled. For example in:
```rust
pub fn b(s: String) -> String {
a(s)
}
#[inline]
pub fn a(s: String) -> String {
let x = s;
let y = x;
y
}
```
Auto merge of #73461 - calebzulawski:validate-attribute-placement, r=matthewjasper
Validate built-in attribute placement
Closes #54584, closes #47725, closes #54044.
I've changed silently ignoring some incorrectly placed attributes to errors. I'm not sure what the policy is since this can theoretically break code (should they be warnings instead? does it warrant a crater run?).
Mark Rousskov [Sat, 12 Sep 2020 19:10:13 +0000 (15:10 -0400)]
Set link-shared if LLVM ThinLTO is enabled in config.rs
This avoids missing a shared build when uplifting LLVM artifacts into the
sysroot. We were already producing a shared link anyway, though, so this is not
a visible change from the end user's perspective.
Auto merge of #76538 - fusion-engineering-forks:check-useless-unstable-trait-impl, r=lcnr
Warn for #[unstable] on trait impls when it has no effect.
Earlier today I sent a PR with an `#[unstable]` attribute on a trait `impl`, but was informed that this attribute has no effect there. (comment: https://github.com/rust-lang/rust/pull/76525#issuecomment-689678895, issue: https://github.com/rust-lang/rust/issues/55436)
This PR adds a warning for this situation. Trait `impl` blocks with `#[unstable]` where both the type and the trait are stable will result in a warning:
```
warning: An `#[unstable]` annotation here has no effect. See issue #55436 <https://github.com/rust-lang/rust/issues/55436> for more information.
--> library/std/src/panic.rs:235:1
|
235 | #[unstable(feature = "integer_atomics", issue = "32976")]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
---
It detects three problems in the existing code:
1. A few `RefUnwindSafe` implementations for the atomic integer types in `library/std/src/panic.rs`. Example:
https://github.com/rust-lang/rust/blob/d92155bf6ae0b7d79fc83cbeeb0cc0c765353471/library/std/src/panic.rs#L235-L236
2. An implementation of `Error` for `LayoutErr` in `library/std/srd/error.rs`:
https://github.com/rust-lang/rust/blob/d92155bf6ae0b7d79fc83cbeeb0cc0c765353471/library/std/src/error.rs#L392-L397
3. `From` implementations for `Waker` and `RawWaker` in `library/alloc/src/task.rs`. Example:
https://github.com/rust-lang/rust/blob/d92155bf6ae0b7d79fc83cbeeb0cc0c765353471/library/alloc/src/task.rs#L36-L37
Case 3 interesting: It has a bound with an `#[unstable]` trait (`W: Wake`), so appears to have much effect on stable code. It does however break similar blanket implementations. It would also have immediate effect if `Wake` was implemented for any stable type. (Which is not the case right now, but there are no warnings in place to prevent it.) Whether this case is a problem or not is not clear to me. If it isn't, adding a simple `c.visit_generics(..);` to this PR will stop the warning for this case.
Auto merge of #76639 - Mark-Simulacrum:ci-hosts, r=pietroalbini
Add host triples to CI builders
This is a follow-up to #76415, which changed how x.py interprets cross-compilation target/host flags. This should fix the known cases, but I'm still working through CI logs before/after that PR to identify if anything else is missing.
Mark Rousskov [Sat, 12 Sep 2020 14:05:10 +0000 (10:05 -0400)]
Print all step timings
It is really painful to inspect differences in what was built in CI if things
are appearing and disappearing randomly as they hover around the 100ms mark. No
matter what we choose there's always going to be quite a bit of variability on
CI in timing, so we're going to see things appear and vanish.
Auto merge of #76632 - andjo403:updateDep, r=Mark-Simulacrum
update the version of itertools and parking_lot
this is to avoid compiling multiple version of the crates in rustc speeding up compilation of rustc
an old version of parking_lot is still used in measureme but new version will not be released for some time see [zulip chat](https://rust-lang.zulipchat.com/#narrow/stream/187831-t-compiler.2Fwg-self-profile/topic/new.20release.20of.20measureme)