Matthias Krüger [Wed, 16 Feb 2022 17:59:29 +0000 (18:59 +0100)]
Rollup merge of #93962 - joboet:branchless_slice_ord, r=Mark-Simulacrum
Make [u8]::cmp implementation branchless
The current implementation generates rather ugly assembly code, branching when the common parts are equal. By performing the comparison of the lengths upfront using a subtraction, the assembly gets much prettier: https://godbolt.org/z/4e5fnEKGd.
This will probably not impact speed too much, as the expensive part is in most cases the `memcmp`, but it sure looks better (I'm porting a sorting algorithm currently, and that branch just bothered me).
Matthias Krüger [Wed, 16 Feb 2022 17:59:27 +0000 (18:59 +0100)]
Rollup merge of #92366 - jhpratt:derive-default-enum, r=Mark-Simulacrum
Resolve concern of `derive_default_enum`
This resolves the concern in favor of prohibiting multiple instances of
the attribute. This is similar to non-helper attributes as introduced in
#88681.
bors [Tue, 15 Feb 2022 21:20:49 +0000 (21:20 +0000)]
Auto merge of #93439 - abrown:cf-protection, r=nagisa
Add support for control-flow protection
This change adds a flag for configuring control-flow protection in the LLVM backend. In Clang, this flag is exposed as `-fcf-protection` with options `none|branch|return|full`. This convention is followed for `rustc`, though as a codegen option: `rustc -Z cf-protection=<none|branch|return|full>`. Tracking issue for future work is #93754.
bors [Tue, 15 Feb 2022 16:48:26 +0000 (16:48 +0000)]
Auto merge of #94024 - matthiaskrgr:rollup-0hwxm0w, r=matthiaskrgr
Rollup of 5 pull requests
Successful merges:
- #93899 (Describe VecDeque with more consistent names)
- #93949 (Add basic platform support to library/{panic_}unwind for m68k)
- #93999 (suggest using raw strings when invalid escapes appear in literals)
- #94001 (llvm: migrate to new parameter-bearing uwtable attr)
- #94014 (Move transmute_undefined_repr back to nursery)
Failed merges:
- #94020 (Support pretty printing of invalid constants)
Matthias Krüger [Tue, 15 Feb 2022 15:02:37 +0000 (16:02 +0100)]
Rollup merge of #94014 - flip1995:clippy_transmute_lint_regroup, r=dtolnay
Move transmute_undefined_repr back to nursery
There's still open discussion if this lint is ready to be enabled by
default. We want to give us more time to figure this out and prevent
this lint from getting to stable as an enabled-by-default lint.
cc https://github.com/rust-lang/rust-clippy/pull/8432
r? `@Manishearth` `@dtolnay`
I think this is the way to go here. We can re-enable this lint with the next sync, if we should decide to do so. But I would hold of for this release.
We have until Friday (beta branching) to decide if we want to merge this.
Matthias Krüger [Tue, 15 Feb 2022 15:02:37 +0000 (16:02 +0100)]
Rollup merge of #94001 - durin42:llvm-15-uwtable, r=nikic
llvm: migrate to new parameter-bearing uwtable attr
In https://reviews.llvm.org/D114543 the uwtable attribute gained a flag
so that we can ask for sync uwtables instead of async, as the former are
much cheaper. The default is async, so that's what I've done here, but I
left a TODO that we might be able to do better.
While in here I went ahead and dropped support for removing uwtable
attributes in rustc: we never did it, so I didn't write the extra C++
bridge code to make it work. Maybe I should have done the same thing
with the `sync|async` parameter but we'll see.
Matthias Krüger [Tue, 15 Feb 2022 15:02:35 +0000 (16:02 +0100)]
Rollup merge of #93999 - barzamin:suggest-raw-strings, r=jackh726
suggest using raw strings when invalid escapes appear in literals
i'd guess about 70% of "bad escape" cases occur when someone meant to use a raw string literal because they're passing it directly to `Regex::new()`.
this emits an advisory (`Applicability::MaybeIncorrect`) `help:` suggestion to the user that they use an `r""` string, on top of the normal notes about looking at the string literal documentation/spec.
Matthias Krüger [Tue, 15 Feb 2022 15:02:34 +0000 (16:02 +0100)]
Rollup merge of #93899 - ssomers:vecdeque_naming, r=m-ou-se
Describe VecDeque with more consistent names
The public documentation of VecDeque starts describing itself as a "queue". In method descriptions, it's ~~never~~ sometimes named queue again, or `VecDeque` (IMO a sometimes useful and often noisy notation) or "deque" or "vector". In examples, `deque`, `v` (hidden in `range_mut`) or `vector`. Here is a subjective attempt at more consistency.
bors [Tue, 15 Feb 2022 11:59:37 +0000 (11:59 +0000)]
Auto merge of #93148 - nnethercote:Uniq, r=fee1-dead
Overhaul interning.
A number of types are interned and `eq` and `hash` are implemented on
the pointer rather than the contents. But this is not well enforced
within the type system like you might expect.
This PR introduces a new type `Interned` which encapsulates this concept
more rigorously, and uses it to convert a couple of the less common
interned types.
flip1995 [Tue, 15 Feb 2022 09:54:38 +0000 (10:54 +0100)]
Move transmute_undefined_repr back to nursery
There's still open discussion if this lint is ready to be enabled by
default. We want to give us more time to figure this out and prevent
this lint from getting to stable as an enabled-by-default lint.
bors [Tue, 15 Feb 2022 09:32:03 +0000 (09:32 +0000)]
Auto merge of #93176 - danielhenrymantilla:stack-pinning-macro, r=m-ou-se
Add a stack-`pin!`-ning macro to `core::pin`.
- https://github.com/rust-lang/rust/issues/93178
`pin!` allows pinning a value to the stack. Thanks to being implemented in the stdlib, which gives access to `macro` macros, and to the private `.pointer` field of the `Pin` wrapper, [it was recently discovered](https://rust-lang.zulipchat.com/#narrow/stream/187312-wg-async-foundations/topic/pin!.20.E2.80.94.20the.20.22definitive.22.20edition.20.28a.20rhs-compatible.20pin-nin.2E.2E.2E/near/268731241) ([archive link](https://zulip-archive.rust-lang.org/stream/187312-wg-async-foundations/topic/A.20rhs-compatible.20pin-ning.20macro.html#268731241)), contrary to popular belief, that it is actually possible to implement and feature such a macro:
This macro thus allows, for instance, doing things like:
```diff
fn block_on<T>(fut: impl Future<Output = T>) -> T {
// Pin the future so it can be polled.
- let mut fut = Box::pin(fut);
+ let mut fut = pin!(fut);
// Create a new context to be passed to the future.
let t = thread::current();
let waker = Arc::new(ThreadWaker(t)).into();
let mut cx = Context::from_waker(&waker);
// Run the future to completion.
loop {
match fut.as_mut().poll(&mut cx) {
Poll::Ready(res) => return res,
Poll::Pending => thread::park(),
}
}
}
```
I don't think such an API can get better than that, barring full featured language support (`&pin` references or something), so I see no reason not to start experimenting with featuring this in the stdlib already 🙂
- cc `@rust-lang/wg-async-foundations` \[EDIT: this doesn't seem to have pinged anybody 😩, thanks `@yoshuawuyts` for the real ping\]
- The key for it working lies in [the rules governing the scope of anonymous temporaries](https://doc.rust-lang.org/1.58.1/reference/destructors.html#temporary-lifetime-extension).
<details><summary>Comments and context</summary>
This is `Pin::new_unchecked(&mut { $value })`, so, for starters, let's
review such a hypothetical macro (that any user-code could define):
```rust
macro_rules! pin {( $value:expr ) => (
match &mut { $value } { at_value => unsafe { // Do not wrap `$value` in an `unsafe` block.
$crate::pin::Pin::<&mut _>::new_unchecked(at_value)
}}
)}
```
Safety:
- `type P = &mut _`. There are thus no pathological `Deref{,Mut}` impls that would break `Pin`'s invariants.
- `{ $value }` is braced, making it a _block expression_, thus **moving** the given `$value`, and making it _become an **anonymous** temporary_.
By virtue of being anonynomous, it can no longer be accessed, thus preventing any attemps to `mem::replace` it or `mem::forget` it, _etc._
This gives us a `pin!` definition that is sound, and which works, but only in certain scenarios:
- If the `pin!(value)` expression is _directly_ fed to a function call:
`let poll = pin!(fut).poll(cx);`
- If the `pin!(value)` expression is part of a scrutinee:
```rust
match pin!(fut) { pinned_fut => {
pinned_fut.as_mut().poll(...);
pinned_fut.as_mut().poll(...);
}} // <- `fut` is dropped here.
```
Alas, it doesn't work for the more straight-forward use-case: `let` bindings.
```rust
let pinned_fut = pin!(fut); // <- temporary value is freed at the end of this statement
pinned_fut.poll(...) // error[E0716]: temporary value dropped while borrowed
// note: consider using a `let` binding to create a longer lived value
```
- Issues such as this one are the ones motivating https://github.com/rust-lang/rfcs/pull/66
This makes such a macro incredibly unergonomic in practice, and the reason most macros out there had to take the path of being a statement/binding macro (_e.g._, `pin!(future);`) instead of featuring the more intuitive ergonomics of an expression macro.
Luckily, there is a way to avoid the problem. Indeed, the problem stems from the fact that a temporary is dropped at the end of its enclosing statement when it is part of the parameters given to function call, which has precisely been the case with our `Pin::new_unchecked()`!
For instance,
```rust
let p = Pin::new_unchecked(&mut <temporary>);
```
becomes:
```rust
let p = { let mut anon = <temporary>; &mut anon };
```
However, when using a literal braced struct to construct the value, references to temporaries can then be taken. This makes Rust change the lifespan of such temporaries so that they are, instead, dropped _at the end of the enscoping block_.
For instance,
```rust
let p = Pin { pointer: &mut <temporary> };
```
becomes:
```rust
let mut anon = <temporary>;
let p = Pin { pointer: &mut anon };
```
which is *exactly* what we want.
Finally, we don't hit problems _w.r.t._ the privacy of the `pointer` field, or the unqualified `Pin` name, thanks to `decl_macro`s being _fully_ hygienic (`def_site` hygiene).
</details>
___
# TODO
- [x] Add compile-fail tests with attempts to break the `Pin` invariants thanks to the macro (_e.g._, try to access the private `.pointer` field, or see what happens if such a pin is used outside its enscoping scope (borrow error));
- [ ] Follow-up stuff:
- [ ] Try to experiment with adding `pin!` to the prelude: this may require to be handled with some extra care, as it may lead to issues reminiscent of those of `assert_matches!`: https://github.com/rust-lang/rust/issues/82913
- [x] Create the tracking issue.
bors [Tue, 15 Feb 2022 07:04:10 +0000 (07:04 +0000)]
Auto merge of #93918 - jonhoo:bootstrap-native-envflags, r=Mark-Simulacrum
bootstrap: tidy up flag handling for llvm build
This tidies up the logic in `src/bootstrap/native.rs` such that:
- `CMAKE_*_LINKER_FLAGS` is not overridden if we add to it twice.
- `CMAKE_*_FLAGS` also include the standard `*FLAGS` environment
variables, which CMake respects when we _don't_ set `CMAKE_*_FLAGS`.
- `llvm.ldflags` from `config.toml` appends to the ldflags Rust's
bootstrap logic adds, rather than replacing them.
It also takes a second stab at #89983 by moving `-static-libstdc++` to just be passed as a linker flag, since that's what it is.
Specifically, rename the `Const` struct as `ConstS` and re-introduce `Const` as
this:
```
pub struct Const<'tcx>(&'tcx Interned<ConstS>);
```
This now matches `Ty` and `Predicate` more closely, including using
pointer-based `eq` and `hash`.
Notable changes:
- `mk_const` now takes a `ConstS`.
- `Const` was copy, despite being 48 bytes. Now `ConstS` is not, so need a
we need separate arena for it, because we can't use the `Dropless` one any
more.
- Many `&'tcx Const<'tcx>`/`&Const<'tcx>` to `Const<'tcx>` changes
- Many `ct.ty` to `ct.ty()` and `ct.val` to `ct.val()` changes.
- Lots of tedious sigil fiddling.
The variant names are exported, so we can use them directly (possibly
with a `ty::` qualifier). Lots of places already do this, this commit
just increases consistency.
Specifically, change `Region` from this:
```
pub type Region<'tcx> = &'tcx RegionKind;
```
to this:
```
pub struct Region<'tcx>(&'tcx Interned<RegionKind>);
```
This now matches `Ty` and `Predicate` more closely.
Things to note
- Regions have always been interned, but we haven't been using pointer-based
`Eq` and `Hash`. This is now happening.
- I chose to impl `Deref` for `Region` because it makes pattern matching a lot
nicer, and `Region` can be viewed as just a smart wrapper for `RegionKind`.
- Various methods are moved from `RegionKind` to `Region`.
- There is a lot of tedious sigil changes.
- A couple of types like `HighlightBuilder`, `RegionHighlightMode` now have a
`'tcx` lifetime because they hold a `Ty<'tcx>`, so they can call `mk_region`.
- A couple of test outputs change slightly, I'm not sure why, but the new
outputs are a little better.
Specifically, change `Ty` from this:
```
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
```
to this
```
pub struct Ty<'tcx>(Interned<'tcx, TyS<'tcx>>);
```
There are two benefits to this.
- It's now a first class type, so we can define methods on it. This
means we can move a lot of methods away from `TyS`, leaving `TyS` as a
barely-used type, which is appropriate given that it's not meant to
be used directly.
- The uniqueness requirement is now explicit, via the `Interned` type.
E.g. the pointer-based `Eq` and `Hash` comes from `Interned`, rather
than via `TyS`, which wasn't obvious at all.
Much of this commit is boring churn. The interesting changes are in
these files:
- compiler/rustc_middle/src/arena.rs
- compiler/rustc_middle/src/mir/visit.rs
- compiler/rustc_middle/src/ty/context.rs
- compiler/rustc_middle/src/ty/mod.rs
Specifically:
- Most mentions of `TyS` are removed. It's very much a dumb struct now;
`Ty` has all the smarts.
- `TyS` now has `crate` visibility instead of `pub`.
- `TyS::make_for_test` is removed in favour of the static `BOOL_TY`,
which just works better with the new structure.
- The `Eq`/`Ord`/`Hash` impls are removed from `TyS`. `Interned`s impls
of `Eq`/`Hash` now suffice. `Ord` is now partly on `Interned`
(pointer-based, for the `Equal` case) and partly on `TyS`
(contents-based, for the other cases).
- There are many tedious sigil adjustments, i.e. adding or removing `*`
or `&`. They seem to be unavoidable.
In particular, there's now more protection against incorrect usage,
because you can only create one via `Interned::new_unchecked`, which
makes it more obvious that you must be careful.
bors [Tue, 15 Feb 2022 04:39:37 +0000 (04:39 +0000)]
Auto merge of #93863 - pierwill:fix-93676, r=Mark-Simulacrum
Update `sha1`, `sha2`, and `md-5` dependencies
This replaces the deprecated [`cpuid-bool`](https://crates.io/crates/cpuid-bool) dependency with [`cpufeatures`](https://crates.io/crates/cpufeatures), while adding [`crypto-common`](https://crates.io/crates/crypto-common) as a new dependency.
bors [Tue, 15 Feb 2022 02:27:37 +0000 (02:27 +0000)]
Auto merge of #93752 - eholk:drop-tracking-break-continue, r=nikomatsakis
Generator drop tracking: improve break and continue handling
This PR fixes two related issues.
One, sometimes break or continue have a block target instead of an expression target. This seems to mainly happen with try blocks. Since the drop tracking analysis only works on expressions, if we see a block target for break or continue, we substitute the last expression of the block as the target instead.
Two, break and continue were incorrectly being treated as the same, so continue would also show up as an exit from the loop or block. This patch corrects the way continue is handled by keeping a stack of loop entry points and uses those to find the target of the continue.
Augie Fackler [Mon, 14 Feb 2022 19:01:19 +0000 (14:01 -0500)]
llvm: migrate to new parameter-bearing uwtable attr
In https://reviews.llvm.org/D114543 the uwtable attribute gained a flag
so that we can ask for sync uwtables instead of async, as the former are
much cheaper. The default is async, so that's what I've done here, but I
left a TODO that we might be able to do better.
While in here I went ahead and dropped support for removing uwtable
attributes in rustc: we never did it, so I didn't write the extra C++
bridge code to make it work. Maybe I should have done the same thing
with the `sync|async` parameter but we'll see.
suggest using raw string literals when invalid escapes appear
i'd guess about 70% of "bad escape" cases occur when someone meant to
use a raw string literal because they're passing it directly to
Regex::new(). this emits an advisory (Applicability::MaybeIncorrect)
help: suggestion to the user that they use an r"" string,
on top of the normal notes about looking at the
string literal documentation/spec.
Andrew Brown [Fri, 28 Jan 2022 17:48:59 +0000 (09:48 -0800)]
Add support for control-flow protection
This change adds a flag for configuring control-flow protection in the
LLVM backend. In Clang, this flag is exposed as `-fcf-protection` with
options `none|branch|return|full`. This convention is followed for
`rustc`, though as a codegen option: `rustc -Z
cf-protection=<none|branch|return|full>`.
This thus still makes it technically possible to enable the feature, and thus
to trigger UB without `unsafe`, but this is fine since incomplete features are
known to be potentially unsound (labelled "may not be safe").
This follows from the discussion at https://github.com/rust-lang/rust/pull/93176#discussion_r799413561
Replace `def_site`-&-privacy implementation with a stability-based one.
Since `decl_macro`s and/or `Span::def_site()` is deemed quite unstable,
no public-facing macro that relies on it can hope to be, itself, stabilized.
We circumvent the issue by no longer relying on field privacy for safety and,
instead, relying on an unstable feature-gate to act as the gate keeper for
non users of the macro (thanks to `allow_internal_unstable`).
This is technically not correct (since a `nightly` user could technically enable
the feature and cause unsoundness with it); or, in other words, this makes the
feature-gate used to gate the access to the field be (technically unsound, and
in practice) `unsafe`. Hence it having `unsafe` in its name.
Back to the macro, we go back to `macro_rules!` / `mixed_site()`-span rules thanks
to declaring the `decl_macro` as `semitransparent`, which is a hack to basically have
`pub macro_rules!`
bors [Mon, 14 Feb 2022 12:26:43 +0000 (12:26 +0000)]
Auto merge of #93938 - BoxyUwU:fix_res_self_ty, r=lcnr
Make `Res::SelfTy` a struct variant and update docs
I found pattern matching on a `(Option<DefId>, Option<(DefId, bool)>)` to not be super readable, additionally the doc comments on the types in a tuple variant aren't visible anywhere at use sites as far as I can tell (using rust analyzer + vscode)
The docs incorrectly assumed that the `DefId` in `Option<(DefId, bool)>` would only ever be for an impl item and I also found the code examples to be somewhat unclear about which `DefId` was being talked about.
r? `@lcnr` since you reviewed the last PR changing these docs
bors [Mon, 14 Feb 2022 05:55:26 +0000 (05:55 +0000)]
Auto merge of #93937 - bjorn3:simplifications3, r=cjgillot
Remove Config::stderr
1. It captured stdout and not stderr
2. It isn't used anywhere
3. All error messages should go to the DiagnosticOutput instead
4. It modifies thread local state
Marking as blocked as it will conflict a bit with https://github.com/rust-lang/rust/pull/93936.
bors [Sun, 13 Feb 2022 20:46:42 +0000 (20:46 +0000)]
Auto merge of #83822 - petrochenkov:linkandro, r=davidtwco
rustc_target: Remove compiler-rt linking hack on Android
`compiler-rt` did some significant work last year trying to eliminate this kind of duplicated symbols, so the flag may be no longer necessary.
Tested locally with AArch64 Android, seems to work, CI will check the rest of the targets.
bors [Sun, 13 Feb 2022 17:41:31 +0000 (17:41 +0000)]
Auto merge of #93837 - nikic:arm-update, r=Mark-Simulacrum
Update dist-(arm|armv7|armhf)-linux to Ubuntu 20.04
I believe this should be safe, as actual artifacts will be produced by a cross toolchain. The build ran through cleanly locally.
This came up in https://github.com/rust-lang/rust/pull/93577, where the host GCC ICEd during the LLD build. (Though I wonder why we build LLD for the host at all...)
bors [Sun, 13 Feb 2022 15:12:21 +0000 (15:12 +0000)]
Auto merge of #93685 - Mark-Simulacrum:drop-time, r=Mark-Simulacrum
Drop time dependency from bootstrap
This was only used for the inclusion of 'current' dates into our manpages, but
it is not clear that this is practically necessary. The manpage is essentially
never updated, and so we can likely afford to keep a manual date in these files.
It also seems possible to just omit it, but that may cause other tools trouble,
so avoid doing that for now.
This is largely done to reduce bootstrap complexity; the time crate is not particularly
small and in #92480 would have started pulling in num-threads, which does runtime
thread count detection. I would prefer to avoid that, so filing this to just drop the nearly
unused dependency entirely.
bors [Sun, 13 Feb 2022 12:03:52 +0000 (12:03 +0000)]
Auto merge of #91673 - ChrisDenton:path-absolute, r=Mark-Simulacrum
`std::path::absolute`
Implements #59117 by adding a `std::path::absolute` function that creates an absolute path without reading the filesystem. This is intended to be a drop-in replacement for [`std::fs::canonicalize`](https://doc.rust-lang.org/std/fs/fn.canonicalize.html) in cases where it isn't necessary to resolve symlinks. It can be used on paths that don't exist or where resolving symlinks is unwanted. It can also be used to avoid circumstances where `canonicalize` might otherwise fail.
On Windows this is a wrapper around [`GetFullPathNameW`](https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getfullpathnamew). On Unix it partially implements the POSIX [pathname resolution](https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13) specification, stopping just short of actually resolving symlinks.
bjorn3 [Fri, 25 Jun 2021 10:58:21 +0000 (12:58 +0200)]
Remove Config::stderr
1. It captured stdout and not stderr
2. It isn't used anywhere
3. All error messages should go to the DiagnosticOutput instead
4. It modifies thread local state
bors [Sun, 13 Feb 2022 09:41:41 +0000 (09:41 +0000)]
Auto merge of #93763 - jsha:re-space-empty-impls, r=GuillaumeGomez
rustdoc: fix spacing of non-toggled impl blocks
We [recently removed the "up here" arrows on item-infos](https://github.com/rust-lang/rust/pull/92651), and adjusted
vertical spacing so that even without the arrow, it would be visually
clear which item the item-info belonged to. The new CSS styles for
vertical spacing only applied to toggles, though. This missed
non-toggled impl blocks - for instance, those without any methods, like
https://doc.rust-lang.org/nightly/std/marker/trait.Send.html#implementors.
The result was lists of implementors that were spaced too closely. This
PR fixes the spacing by making it apply to non-toggled impl blocks as
well.
This also fixes an issue where item-infos were displayed too far below
their items. That was a result of display: table on .item-info .stab.
Changed that to display: inline-block.
bors [Sun, 13 Feb 2022 07:04:56 +0000 (07:04 +0000)]
Auto merge of #93956 - matthiaskrgr:rollup-zfk35hb, r=matthiaskrgr
Rollup of 9 pull requests
Successful merges:
- #89926 (make `Instant::{duration_since, elapsed, sub}` saturating and remove workarounds)
- #90532 (More informative error message for E0015)
- #93810 (Improve chalk integration)
- #93851 (More practical examples for `Option::and_then` & `Result::and_then`)
- #93885 (bootstrap.py: Suggest disabling download-ci-llvm option if url fails to download)
- #93886 (Stabilise inherent_ascii_escape (FCP in #77174))
- #93930 (add link to format_args! when mention it in docs)
- #93936 (Couple of driver cleanups)
- #93944 (Don't relabel to a team if there is already a team label)
Matthias Krüger [Sun, 13 Feb 2022 05:44:19 +0000 (06:44 +0100)]
Rollup merge of #93944 - jackh726:team-exclude, r=Mark-Simulacrum
Don't relabel to a team if there is already a team label
Should prevent cases like #93628, where teams have been manually assigned, but changes are pushed. We give up adding new labels on *new* changes; but I feel like that is less frequent.
Matthias Krüger [Sun, 13 Feb 2022 05:44:18 +0000 (06:44 +0100)]
Rollup merge of #93936 - bjorn3:simplifications2, r=cjgillot
Couple of driver cleanups
* Remove the `RustcDefaultCalls` struct, which hasn't been necessary since the introduction of `rustc_interface`.
* Move the `setup_callbacks` call around for a tiny code deduplication.
* Remove the `SPAN_DEBUG` global as it isn't actually necessary.
Matthias Krüger [Sun, 13 Feb 2022 05:44:17 +0000 (06:44 +0100)]
Rollup merge of #93886 - clarfonthey:stable_ascii_escape, r=Mark-Simulacrum
Stabilise inherent_ascii_escape (FCP in #77174)
Implements #77174, which completed its FCP.
This does *not* deprecate any existing methods or structs, as that is tracked in #93887. That stated, people should prefer using `u8::escape_ascii` to `std::ascii::escape_default`.
Matthias Krüger [Sun, 13 Feb 2022 05:44:16 +0000 (06:44 +0100)]
Rollup merge of #93885 - Badel2:error-download-ci-llvm, r=Mark-Simulacrum
bootstrap.py: Suggest disabling download-ci-llvm option if url fails to download
I got an error when trying to build the compiler using an old commit, and it turns out it was because the option `download-ci-llvm` was implicitly set to true. So this pull request tries to add a help message for other people that may run into the same problem.
```
# Includes one of the default files in src/bootstrap/defaults
profile = "compiler"
changelog-seen = 2
[rust]
debug = true
```
To reproduce an error with this branch:
Change line 618 of bootstrap.py to
```
url = "rustc-builds-error404/{}".format(llvm_sha)
```
Delete llvm and cached tarball, and set `llvm.download-ci-llvm=true` in config.toml.
```
./x.py test
[...]
spurious failure, trying again
downloading https://ci-artifacts.rust-lang.org/rustc-builds-error404/719b04ca99be0c78e09a8ec5e2eda082a5d8ccae/rust-dev-nightly-x86_64-unknown-linux-gnu.tar.xz
curl: (22) The requested URL returned error: 404
failed to run: curl -# -y 30 -Y 10 --connect-timeout 30 --retry 3 -Sf -o /tmp/tmpesl1ydvo https://ci-artifacts.rust-lang.org/rustc-builds-error404/719b04ca99be0c78e09a8ec5e2eda082a5d8ccae/rust-dev-nightly-x86_64-unknown-linux-gnu.tar.xz
error: failed to download llvm from ci
help: old builds get deleted after a certain time
help: if trying to compile an old commit of rustc, disable `download-ci-llvm` in config.toml:
[llvm]
download-ci-llvm = false
Build completed unsuccessfully in 0:00:01
```
Regarding the implementation, I expected to be able to use a try/catch block in `_download_ci_llvm`, but the `run` function calls `sys.exit` instead of raising an exception so that's not possible. Also, suggestions for better wording of the help message are welcome.
Matthias Krüger [Sun, 13 Feb 2022 05:44:15 +0000 (06:44 +0100)]
Rollup merge of #93851 - cyqsimon:option-examples, r=scottmcm
More practical examples for `Option::and_then` & `Result::and_then`
To be blatantly honest, I think the current example given for `Option::and_then` is objectively terrible. (No offence to whoever wrote them initially.)
Current example:
- does not demonstrate that `and_then` converts `Option<T>` to `Option<U>`
- is far removed from any realistic code
- generally just causes more confusion than it helps
So I replaced them with two blocks:
- the first one shows basic usage (including the type conversion)
- the second one shows an example of typical usage
Matthias Krüger [Sun, 13 Feb 2022 05:44:14 +0000 (06:44 +0100)]
Rollup merge of #93810 - matthewjasper:chalk-and-canonical-universes, r=jackh726
Improve chalk integration
- Support subtype bounds in chalk lowering
- Handle universes in canonicalization
- Handle type parameters in chalk responses
- Use `chalk_ir::LifetimeData::Empty` for `ty::ReEmpty`
- Remove `ignore-compare-mode-chalk` for tests that no longer hang (they may still fail or ICE)
This is enough to get a hello world program to compile with `-Zchalk` now. Some of the remaining issues that are needed to get Chalk integration working on larger programs are:
- rust-lang/chalk#234
- rust-lang/chalk#548
- rust-lang/chalk#734
- Generators are handled differently in chalk and rustc
Matthias Krüger [Sun, 13 Feb 2022 05:44:12 +0000 (06:44 +0100)]
Rollup merge of #89926 - the8472:saturate-instant, r=Mark-Simulacrum
make `Instant::{duration_since, elapsed, sub}` saturating and remove workarounds
This removes all mutex/atomic-based workarounds for non-monotonic clocks and makes the previously panicking methods saturating instead. Additionally `saturating_duration_since` becomes deprecated since `duration_since` now fills that role.
Effectively this moves the fixup from `Instant` construction to the comparisons.
This has some observable effects, especially on platforms without monotonic clocks:
* Incorrectly ordered Instant comparisons no longer panic in release mode. This could hide some programming errors, but since debug mode still panics tests can still catch them.
* `checked_duration_since` will now return `None` in more cases. Previously it only happened when one compared instants obtained in the wrong order or manually created ones. Now it also does on backslides.
* non-monotonic intervals will not be transitive, i.e. `b.duration_since(a) + c.duration_since(b) != c.duration_since(a)`
The upsides are reduced complexity and lower overhead of `Instant::now`.
## Motivation
Currently we must choose between two poisons. One is high worst-case latency and jitter of `Instant::now()` due to explicit synchronization; see #83093 for benchmarks, the worst-case overhead is > 100x. The other is sporadic panics on specific, rare combinations of CPU/hypervisor/operating system due to platform bugs.
Use-cases where low-overhead, fine-grained timestamps are needed - such as syscall tracing, performance profiles or sensor data acquisition (drone flight controllers were mentioned in a libs meeting) in multi-threaded programs - are negatively impacted by the synchronization.
The panics are user-visible (program crashes), hard to reproduce and can be triggered by any dependency that might be using Instants for any reason.
A solution that is fast _and_ doesn't panic is desirable.
bors [Sun, 13 Feb 2022 04:48:05 +0000 (04:48 +0000)]
Auto merge of #93713 - klensy:deps-up, r=Mark-Simulacrum
Update deps
cargo_metadata 0.12 -> 0.14, to dedupe and remove some `semver`, `semver-parser` versions
pretty_assertions 0.6 -> 0.7, to drop some `ansi_term` version
futures 0.1.29 -> 0.1.31, backported some [fixes](https://github.com/rust-lang/futures-rs/compare/0.1.29...0.1.31) to old versions
futures-* 0.3.12 -> 0.3.19, to remove `proc-macro-hack`, `proc-macro-nested` and fix some [issues](https://github.com/rust-lang/futures-rs/blob/master/CHANGELOG.md#0319---2021-12-18). There exist 0.3.21, but it's quite new (06.02.22), so not updated to.
itertools 0.9 -> 0.10 for rustdoc, will be droppped when rustfmt will bump `itertools` version
linked-hash-map 0.5.3 -> 0.5.4, fix [UB](https://github.com/contain-rs/linked-hash-map/pull/106)
markup5ever 0.10.0 -> 0.10.1, internally drops `serde`, reducing [build time](https://github.com/servo/html5ever/commit/3afd8d63853627e530b3063b0185eea3732cc29f#diff-4c20e8293515259c0aa26932413a55a334aa5f2b37de5a5adc92a2186f632606) for some usecases
mio 0.7.13 -> 0.7.14 fix [unsoundness](https://github.com/tokio-rs/mio/compare/v0.7.13...v0.7.14)
num_cpus 1.13.0 -> 1.13.1 fix parsing mountinfo and other [fixes](https://github.com/seanmonstar/num_cpus/compare/v1.13.0...v1.13.1)
openssl-src 111.16.0+1.1.1l -> 111.17.0+1.1.1m fix CVE-2021-4160
bors [Sun, 13 Feb 2022 02:40:56 +0000 (02:40 +0000)]
Auto merge of #93696 - Amanieu:compiler-builtins-0.1.68, r=Mark-Simulacrum
Bump compiler-builtins to 0.1.69
This includes https://github.com/rust-lang/compiler-builtins/pull/452 which should fix some issues with duplicate symbol defintions of some intrinsics.
bors [Sun, 13 Feb 2022 00:14:52 +0000 (00:14 +0000)]
Auto merge of #93670 - erikdesjardins:noundef, r=nikic
Apply noundef attribute to &T, &mut T, Box<T>, bool
This doesn't handle `char` because it's a bit awkward to distinguish it from `u32` at this point in codegen.
Note that this _does not_ change whether or not it is UB for `&`, `&mut`, or `Box` to point to undef. It only applies to the pointer itself, not the pointed-to memory.