Commit Graph

162957 Commits

Author SHA1 Message Date
Lucas Kent
1973f277a3 Cleanup uses 2022-02-16 15:01:19 +11:00
Lucas Kent
ae212402d6 Make implementation generic 2022-02-16 14:58:36 +11:00
Lucas Kent
8610edd014 Suggest deriving required supertraits 2022-02-16 14:58:36 +11:00
bors
393fdc1048 Auto merge of - tmiasko:inline, r=nagisa
Inline a few trivial conversion functions
2022-02-15 23:48:43 +00:00
bors
09cb29c64c Auto merge of - 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 .
2022-02-15 21:20:49 +00:00
bors
bfb2856f27 Auto merge of - compiler-errors:gat-wfcheck, r=jackh726
Rework GAT `where` clause check

rework the GAT where check to use a fixed-point algorithm, and check all GATs in a trait at once

fixes 

r? `@jackh726`
cc `@nikomatsakis`
2022-02-15 19:03:38 +00:00
Tomasz Miąsko
ea71420761 Inline LocalExpnId::from_raw and LocalExpnId::as_raw 2022-02-15 19:08:12 +01:00
Tomasz Miąsko
81f12eb7ef Inline Target::deref 2022-02-15 19:08:12 +01:00
Tomasz Miąsko
d04677750b Inline GenericArg conversion functions 2022-02-15 19:08:08 +01:00
Tomasz Miąsko
cd37638c14 Inline UnifyKey::index and UnifyKey::from_index 2022-02-15 19:07:06 +01:00
Michael Goulet
f045b214ea Add removed comments back in self-outlives-lint 2022-02-15 09:17:09 -08:00
Michael Goulet
ce16189d46 add some more comments to GAT where clause check 2022-02-15 09:17:09 -08:00
Michael Goulet
d8b49f0282 add test for issue-93278, bless 2022-02-15 09:17:09 -08:00
Michael Goulet
477459795d make the gat wfcheck algorithm a loop 2022-02-15 09:17:09 -08:00
Michael Goulet
852a851712 check associated types too 2022-02-15 09:17:09 -08:00
Michael Goulet
453d2dbbd4 check all GATs at once 2022-02-15 09:17:09 -08:00
Michael Goulet
764839320c rename some variables in gat wfcheck 2022-02-15 09:17:09 -08:00
Michael Goulet
5b2291cfa6 introduce gather_gat_bounds 2022-02-15 09:17:07 -08:00
bors
6bf3008f07 Auto merge of - matthiaskrgr:rollup-0hwxm0w, r=matthiaskrgr
Rollup of 5 pull requests

Successful merges:

 -  (Describe VecDeque with more consistent names)
 -  (Add basic platform support to library/{panic_}unwind for m68k)
 -  (suggest using raw strings when invalid escapes appear in literals)
 -  (llvm: migrate to new parameter-bearing uwtable attr)
 -  (Move transmute_undefined_repr back to nursery)

Failed merges:

 -  (Support pretty printing of invalid constants)

r? `@ghost`
`@rustbot` modify labels: rollup
2022-02-15 16:48:26 +00:00
Matthias Krüger
cc836ee292
Rollup merge of - 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.
2022-02-15 16:02:37 +01:00
Matthias Krüger
a87be980d8
Rollup merge of - 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.
2022-02-15 16:02:37 +01:00
Matthias Krüger
c6b27db876
Rollup merge of - 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.
2022-02-15 16:02:35 +01:00
Matthias Krüger
e1baa3d5b9
Rollup merge of - glaubitz:m68k-unwind, r=Mark-Simulacrum
Add basic platform support to library/{panic_}unwind for m68k

This PR adds basic platform support for m68k for library/{panic_}unwind for m68k.

Register information for UNWIND_DATA_REG has been extracted from LLVM.
2022-02-15 16:02:35 +01:00
Matthias Krüger
cdfdcfcf18
Rollup merge of - 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.
2022-02-15 16:02:34 +01:00
bors
5569757491 Auto merge of - 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.

r? `@fee1-dead`
2022-02-15 11:59:37 +00:00
flip1995
6a7fb3b64b
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.
2022-02-15 10:54:38 +01:00
bors
6421a499a5 Auto merge of - 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:

```rust
let foo: Pin<&mut PhantomPinned> = pin!(PhantomPinned);
stuff(foo);
```
or, directly:

```rust
stuff(pin!(PhantomPinned));
```

  - For context, historically, this used to require one of the two following syntaxes:

      - ```rust
        let foo = PhantomPinned;
        pin!(foo);
        stuff(foo);
        ```

      -  ```rust
         pin! {
             let foo = PhantomPinned;
         }
         stuff(foo);
         ```

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(),
        }
    }
}
```

  - _c.f._, https://doc.rust-lang.org/1.58.1/alloc/task/trait.Wake.html

And so on, and so forth.

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` \[EDIT: this doesn't seem to have pinged anybody 😩, thanks `@yoshuawuyts` for the real ping\]

r? `@joshtriplett`

___

# Docs preview

https://user-images.githubusercontent.com/9920355/150605731-1f45c2eb-c9b0-4ce3-b17f-2784fb75786e.mp4

___

# Implementation

The implementation ends up being dead simple (so much it's embarrassing):

```rust
pub macro pin($value:expr $(,)?) {
    Pin { pointer: &mut { $value } }
}
```

_and voilà_!

  - 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.
2022-02-15 09:32:03 +00:00
bors
6655109f58 Auto merge of - 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  by moving `-static-libstdc++` to just be passed as a linker flag, since that's what it is.

Fixes . Fixes . Closes .
2022-02-15 07:04:10 +00:00
Nicholas Nethercote
80632de4a1 Address review comments. 2022-02-15 16:20:01 +11:00
Nicholas Nethercote
a95fb8b150 Overhaul Const.
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.
2022-02-15 16:19:59 +11:00
Nicholas Nethercote
7eb15509ce Remove unnecessary RegionKind:: quals.
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.
2022-02-15 16:14:24 +11:00
Nicholas Nethercote
7024dc523a Overhaul RegionKind and Region.
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.
2022-02-15 16:08:52 +11:00
Nicholas Nethercote
925ec0d3c7 Overhaul PredicateInner and Predicate.
Specifically, change `Ty` from this:
```
pub struct Predicate<'tcx> { inner: &'tcx PredicateInner<'tcx> }
```
to this:
```
pub struct Predicate<'tcx>(&'tcx Interned<PredicateS<'tcx>>)
```
where `PredicateInner` is renamed as `PredicateS`.

 This (plus a few other minor changes) makes the parallels with `Ty` and
`TyS` much clearer, and makes the uniqueness more explicit.
2022-02-15 16:03:26 +11:00
Nicholas Nethercote
e9a0c429c5 Overhaul TyS and Ty.
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.
2022-02-15 16:03:24 +11:00
Nicholas Nethercote
0c2ebbd412 Rename PtrKey as Interned and improve it.
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.

There are also some tests.
2022-02-15 15:50:29 +11:00
Nicholas Nethercote
028e57ba1d Rename Interned as InternedInSet.
This will let us introduce a more widely-used `Interned` type in the
next commit.
2022-02-15 15:50:29 +11:00
bors
8d163e6621 Auto merge of - 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.

Closes .
2022-02-15 04:39:37 +00:00
bors
0c3f0cddde Auto merge of - 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.

Fixes 

r? `@nikomatsakis`
2022-02-15 02:27:37 +00:00
Augie Fackler
0958c8f4ca 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.
2022-02-14 16:09:53 -05:00
Erin Petra Sofiya Moon
e59cda9ee1
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.
2022-02-14 15:11:38 -05:00
Mara Bos
bf2a9dc375
Update unsafe_pin_internals unstable version. 2022-02-14 19:17:21 +00:00
bors
c5c610aad0 Auto merge of - spastorino:fix-negative-overlap-check-regions, r=nikomatsakis
Fix negative overlap check regions

r? `@nikomatsakis`
2022-02-14 18:28:04 +00:00
Daniel Henry-Mantilla
002f627d38 Add a comment to justify why the pointer field is pub.
Addresses https://github.com/rust-lang/rust/pull/93176/files#r795258110.
2022-02-14 17:35:27 +01:00
Andrew Brown
8d6c973c7f 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>`.

Co-authored-by: BlackHoleFox <blackholefoxdev@gmail.com>
2022-02-14 08:31:24 -08:00
Daniel Henry-Mantilla
c93968aee8 Mark unsafe_pin_internals as incomplete.
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
2022-02-14 17:27:37 +01:00
Daniel Henry-Mantilla
6df63cc148 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!`

Co-Authored-By: Mara Bos <m-ou.se@m-ou.se>
2022-02-14 17:27:37 +01:00
Daniel Henry-Mantilla
54e443dceb Improve documentation.
Co-Authored-By: Mara Bos <m-ou.se@m-ou.se>
2022-02-14 17:27:32 +01:00
Santiago Pastorino
3c7fa0bcf3
reveal_defining_opaque_types field doesn't exist after rebase 2022-02-14 13:02:22 -03:00
Santiago Pastorino
8c4ffaaa7c
Inline loose_check fn on call site 2022-02-14 12:57:22 -03:00
Santiago Pastorino
45983fecff
Add comments about outlives_env 2022-02-14 12:57:22 -03:00