bors [Wed, 9 Mar 2022 02:17:58 +0000 (02:17 +0000)]
Auto merge of #94750 - cuviper:dirent64_min, r=joshtriplett
unix: reduce the size of DirEntry
On platforms where we call `readdir` instead of `readdir_r`, we store
the name as an allocated `CString` for variable length. There's no point
carrying around a full `dirent64` with its fixed-length `d_name` too.
Dylan DPC [Tue, 8 Mar 2022 21:44:00 +0000 (22:44 +0100)]
Rollup merge of #94724 - cuviper:rmdirall-cstr, r=Dylan-DPC
unix: Avoid name conversions in `remove_dir_all_recursive`
Each recursive call was creating an `OsString` for a `&Path`, only for
it to be turned into a `CString` right away. Instead we can directly
pass `.name_cstr()`, saving two allocations each time.
Dylan DPC [Tue, 8 Mar 2022 21:43:59 +0000 (22:43 +0100)]
Rollup merge of #94723 - dtolnay:mustuse, r=Mark-Simulacrum
Add core::hint::must_use
The example code in this documentation is minimized from a real-world situation in the `anyhow` crate where this function would have been valuable.
Having this provided by the standard library is especially useful for proc macros, even more than for macro_rules. That's because proc macro crates aren't allowed to export anything other than macros, so they couldn't make their own `must_use` function for their macro-generated code to call.
<br>
## Rendered documentation
> An identity function that causes an `unused_must_use` warning to be triggered if the given value is not used (returned, stored in a variable, etc) by the caller.
>
> This is primarily intended for use in macro-generated code, in which a [`#[must_use]` attribute][must_use] either on a type or a function would not be convenient.
>
> [must_use]: https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute
>
> ### Example
>
> ```rust
> #![feature(hint_must_use)]
>
> use core::fmt;
>
> pub struct Error(/* ... */);
>
> #[macro_export]
> macro_rules! make_error {
> ($($args:expr),*) => {
> core::hint::must_use({
> let error = $crate::make_error(core::format_args!($($args),*));
> error
> })
> };
> }
>
> // Implementation detail of make_error! macro.
> #[doc(hidden)]
> pub fn make_error(args: fmt::Arguments<'_>) -> Error {
> Error(/* ... */)
> }
>
> fn demo() -> Option<Error> {
> if true {
> // Oops, meant to write `return Some(make_error!("..."));`
> Some(make_error!("..."));
> }
> None
> }
> ```
>
> In the above example, we'd like an `unused_must_use` lint to apply to the value created by `make_error!`. However, neither `#[must_use]` on a struct nor `#[must_use]` on a function is appropriate here, so the macro expands using `core::hint::must_use` instead.
>
> - We wouldn't want `#[must_use]` on the `struct Error` because that would make the following unproblematic code trigger a warning:
>
> ```rust
> fn f(arg: &str) -> Result<(), Error>
>
> #[test]
> fn t() {
> // Assert that `f` returns error if passed an empty string.
> // A value of type `Error` is unused here but that's not a problem.
> f("").unwrap_err();
> }
> ```
>
> - Using `#[must_use]` on `fn make_error` can't help because the return value *is* used, as the right-hand side of a `let` statement. The `let` statement looks useless but is in fact necessary for ensuring that temporaries within the `format_args` expansion are not kept alive past the creation of the `Error`, as keeping them alive past that point can cause autotrait issues in async code:
>
> ```rust
> async fn f() {
> // Using `let` inside the make_error expansion causes temporaries like
> // `unsync()` to drop at the semicolon of that `let` statement, which
> // is prior to the await point. They would otherwise stay around until
> // the semicolon on *this* statement, which is after the await point,
> // and the enclosing Future would not implement Send.
> log(make_error!("look: {:p}", unsync())).await;
> }
>
> async fn log(error: Error) {/* ... */}
>
> // Returns something without a Sync impl.
> fn unsync() -> *const () {
> 0 as *const ()
> }
> ```
Dylan DPC [Tue, 8 Mar 2022 21:43:57 +0000 (22:43 +0100)]
Rollup merge of #94714 - ChrisDenton:win-close_read_wakes_up, r=Mark-Simulacrum
Enable `close_read_wakes_up` test on Windows
I wonder if we could/should try enabling this again? It was closed by #38867 due to #31657. I've tried running this test (along with other tests) on my machine a number of times and haven't seen this fail yet,
Caveat: the worst that can happen is this succeeds initially but then causes random hangs in CI. This is not a great failure mode and would be a reason not to do this.
Dylan DPC [Tue, 8 Mar 2022 21:43:56 +0000 (22:43 +0100)]
Rollup merge of #94689 - compiler-errors:on-unimplemented-substs, r=petrochenkov
Use impl substs in `#[rustc_on_unimplemented]`
We were using the trait-ref substs instead of impl substs in `rustc_on_unimplemented`, even when computing the `rustc_on_unimplemented` attached to an impl block. Let's not do that.
This PR also untangles impl and trait def-ids in the logic in `on_unimplemented` a bit.
Josh Stone [Tue, 8 Mar 2022 21:36:01 +0000 (13:36 -0800)]
unix: reduce the size of DirEntry
On platforms where we call `readdir` instead of `readdir_r`, we store
the name as an allocated `CString` for variable length. There's no point
carrying around a full `dirent64` with its fixed-length `d_name` too.
bors [Tue, 8 Mar 2022 19:25:19 +0000 (19:25 +0000)]
Auto merge of #94702 - b-naber:static-refs-mir, r=lcnr
Reinstate #93800
https://github.com/rust-lang/rust/pull/93800 caused a regression in an alt builder with parallel enabled. https://github.com/rust-lang/rust/pull/94205 reverted that PR because of the regression. For an unknown reason the regression has disappeared, so we reinstate the changes in https://github.com/rust-lang/rust/pull/93800 here.
bors [Tue, 8 Mar 2022 17:04:45 +0000 (17:04 +0000)]
Auto merge of #92260 - jyn514:less-python-logic, r=Mark-Simulacrum
Move some more bootstrap logic from python to rust
Same rationale as https://github.com/rust-lang/rust/pull/76544; it would be nice to make python entirely optional at some point.
This also removes $ROOT as an option for the build directory; I haven't been using it, and like Alex
said in https://github.com/rust-lang/rust/pull/76544#discussion_r488248930 it seems like a misfeature.
This allows running `cargo run` from src/bootstrap, although that still gives
lots of compile errors if you don't use the beta toolchain. It's not exactly the same as using `x.py`, since it won't have `BOOTSTRAP_DOWNLOAD_RUSTC` set, but it's pretty close. Doing this from the top-level directory requires https://github.com/rust-lang/cargo/issues/7290 to be fixed, or using `cargo run -p bootstrap`.
The next steps for making python optional are to move download-ci-llvm and download-rustc support into rustbuild, likely be shelling out as the python scripts do today.
It would also be nice (although not required) to move submodule support there, but that would require taking bootstrap out of the workspace to avoid errors from crates that haven't been cloned yet.
bors [Tue, 8 Mar 2022 10:24:46 +0000 (10:24 +0000)]
Auto merge of #94734 - matthiaskrgr:rollup-28shqhy, r=matthiaskrgr
Rollup of 8 pull requests
Successful merges:
- #91993 (Tweak output for non-exhaustive `match` expression)
- #92385 (Add Result::{ok, err, and, or, unwrap_or} as const)
- #94559 (Remove argument from closure in thread::Scope::spawn.)
- #94580 (Emit `unused_attributes` if a level attr only has a reason)
- #94586 (Generalize `get_nullable_type` to allow types where null is all-ones.)
- #94708 (diagnostics: only talk about `Cargo.toml` if running under Cargo)
- #94712 (promot debug_assert to assert)
- #94726 (:arrow_up: rust-analyzer)
Matthias Krüger [Tue, 8 Mar 2022 10:04:53 +0000 (11:04 +0100)]
Rollup merge of #94586 - sunfishcode:sunfishcode/io-lifetimes-tests, r=davidtwco
Generalize `get_nullable_type` to allow types where null is all-ones.
Generalize get_nullable_type to accept types that have an all-ones bit
pattern as their sentry "null" value.
This will allow [`OwnedFd`], [`BorrowedFd`], [`OwnedSocket`], and
[`BorrowedSocket`] to be marked with
`#[rustc_nonnull_optimization_guaranteed]`, which will allow
`Option<OwnedFd>`, `Option<BorrowedFd>`, `Option<OwnedSocket>`, and
`Option<BorrowedSocket>` to be used in FFI declarations, as described
in the [I/O safety RFC].
For example, it will allow a function like `open` on Unix and `WSASocketW`
on Windows to be declared using `Option<OwnedFd>` and `Option<OwnedSocket>`
return types, respectively.
The actual change to add `#[rustc_nonnull_optimization_guaranteed]`
to the abovementioned types will be a separate PR, as it'll depend on
having this patch in the stage0 compiler.
Also, update the diagnostics to mention that "niche optimizations" are
used in libstd as well as libcore, as `rustc_layout_scalar_valid_range_start`
and `rustc_layout_scalar_valid_range_end` are already in use in libstd.
Matthias Krüger [Tue, 8 Mar 2022 10:04:52 +0000 (11:04 +0100)]
Rollup merge of #94580 - xFrednet:55112-only-reason-in-lint-attr, r=lcnr
Emit `unused_attributes` if a level attr only has a reason
Fixes a comment from `compiler/rustc_lint/src/levels.rs`. Lint level attributes that only contain a reason will also trigger the `unused_attribute` lint. The lint now also checks for the `expect` lint level.
That's it, have a great rest of the day for everyone reasoning this :upside_down_face:
Matthias Krüger [Tue, 8 Mar 2022 10:04:51 +0000 (11:04 +0100)]
Rollup merge of #94559 - m-ou-se:thread-scope-spawn-closure-without-arg, r=Mark-Simulacrum
Remove argument from closure in thread::Scope::spawn.
This implements ```@danielhenrymantilla's``` [suggestion](https://github.com/rust-lang/rust/issues/93203#issuecomment-1040798286) for improving the scoped threads interface.
Summary:
The `Scope` type gets an extra lifetime argument, which represents basically its own lifetime that will be used in `&'scope Scope<'scope, 'env>`:
This simplifies the `spawn` function, which now no longer passes an argument to the closure you give it, and now uses the `'scope` lifetime for everything:
<details><summary>And, as a bonus, errors get <em>slightly</em> better because now any lifetime issues point to the outermost <code>s</code> (since there is only one <code>s</code>), rather than the innermost <code>s</code>, making it clear that the lifetime lasts for the entire <code>thread::scope</code>.
</summary>
```diff
error[E0373]: closure may outlive the current function, but it borrows `a`, which is owned by the current function
--> src/main.rs:9:21
|
- 7 | s.spawn(|s| {
- | - has type `&Scope<'1>`
+ 6 | thread::scope(|s| {
+ | - lifetime `'1` appears in the type of `s`
9 | s.spawn(|| println!("{:?}", a)); // might run after `a` is dropped
| ^^ - `a` is borrowed here
| |
| may outlive borrowed value `a`
|
note: function requires argument type to outlive `'1`
--> src/main.rs:9:13
|
9 | s.spawn(|| println!("{:?}", a)); // might run after `a` is dropped
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to force the closure to take ownership of `a` (and any other referenced variables), use the `move` keyword
|
9 | s.spawn(move || println!("{:?}", a)); // might run after `a` is dropped
| ++++
"
```
</details>
The downside is that the signature of `scope` and `Scope` gets slightly more complex, but in most cases the user wouldn't need to write those, as they just use the argument provided by `thread::scope` without having to name its type.
Another downside is that this does not work nicely in Rust 2015 and Rust 2018, since in those editions, `s` would be captured by reference and not by copy. In those editions, the user would need to use `move ||` to capture `s` by copy. (Which is what the compiler suggests in the error.)
Matthias Krüger [Tue, 8 Mar 2022 10:04:50 +0000 (11:04 +0100)]
Rollup merge of #92385 - clarfonthey:const_option, r=fee1-dead
Add Result::{ok, err, and, or, unwrap_or} as const
Already opened tracking issue #92384.
I don't think that this should actually cause any issues as long as the constness is unstable, but we may want to double-check that this doesn't get interpreted as a weird `Drop` bound even for non-const usages.
Josh Stone [Tue, 8 Mar 2022 02:51:53 +0000 (18:51 -0800)]
unix: Avoid name conversions in `remove_dir_all_recursive`
Each recursive call was creating an `OsString` for a `&Path`, only for
it to be turned into a `CString` right away. Instead we can directly
pass `.name_cstr()`, saving two allocations each time.
Joshua Nelson [Thu, 3 Mar 2022 12:12:32 +0000 (06:12 -0600)]
copy over `std::path::absolute` instead of adding `canonicalize` hacks
this also fixes a bug where bootstrap would try to use the fake `rustc` binary built by bootstrap -
cargo puts it in a different directory when using `cargo run` instead of x.py
Joshua Nelson [Fri, 24 Dec 2021 19:03:02 +0000 (13:03 -0600)]
Move some more bootstrap logic from python to rust
Same rationale as https://github.com/rust-lang/rust/pull/76544;
it would be nice to make python entirely optional at some point.
This also removes $ROOT as an option for the build directory; I haven't been using it, and like Alex
said in https://github.com/rust-lang/rust/pull/76544#discussion_r488248930 it seems like a
misfeature.
This allows running `cargo run` from src/bootstrap, although that still gives
lots of compile errors if you don't use the beta toolchain.
bors [Mon, 7 Mar 2022 21:20:05 +0000 (21:20 +0000)]
Auto merge of #94709 - martingms:link-to-chunked-opt-pr, r=nnethercote
Add link to closed PR for future optimizers of ChunkedBitSet relations
While optimizing these operations proved unfruitful w.r.t. improving compiler performance right now, faster versions might be needed at a later time. This PR adds a link in the FIXME to save any future optimizers some time, as requested by `@nnethercote` in https://github.com/rust-lang/rust/pull/94625.
bors [Mon, 7 Mar 2022 18:06:31 +0000 (18:06 +0000)]
Auto merge of #94706 - matthiaskrgr:rollup-l5erynr, r=matthiaskrgr
Rollup of 4 pull requests
Successful merges:
- #93350 (libunwind: readd link attrs to _Unwind_Backtrace)
- #93827 (Stabilize const_fn_fn_ptr_basics, const_fn_trait_bound, and const_impl_trait)
- #94696 (Remove whitespaces and use CSS to align line numbers to the right instead)
- #94700 (rustdoc: Update minifier version)
Matthias Krüger [Mon, 7 Mar 2022 17:39:03 +0000 (18:39 +0100)]
Rollup merge of #94696 - GuillaumeGomez:align-line-numbers-right, r=notriddle
Remove whitespaces and use CSS to align line numbers to the right instead
Instead of generating whitespaces to create padding, we simply use the CSS rule: `text-align: right`.
Nice side-effect: it reduces the generated HTML size from **75.004** to **74.828** (MegaBytes) on the std source pages (it's not much but it's always a nice plus :laughing: ).
Previously only `Sized` was allowed as a trait bound.
There is no way to call methods from the trait because trait methods cannot currently be marked as const. Allowing trait bounds in const functions does allow the const function to use the trait's associated types and constants.
This feature also allowes `dyn Trait` types. These work equivalently to non-const code. Similar to other pointers in const code, the value of a `dyn Trait` pointer cannot be observed.
Note that due to https://github.com/rust-lang/rust/issues/90912, it was already possible to do the example above as follows:
The following tests include code that exercises `const_fn_trait_bound`:
- `src/test/ui/consts/const-fn.rs`
- `src/test/ui/consts/issue-88071.rs`
- `src/test/ui/consts/min_const_fn/min_const_fn.rs`
- `src/test/ui/consts/min_const_fn/min_const_fn_dyn.rs`
- `src/test/ui/nll/issue-55825-const-fn.rs`
- Many of the tests in `src/test/ui/rfc-2632-const-trait-impl/` also exercise this feature.
## `const_impl_trait`
Allows argument and return position `impl Trait` in a `const fn`, such as in the following example:
Similar to generic parameters and function pointers, this allows the creation of such opaque types, but not doing anything with them beyond accessing associated types and constants.
These features are documented along with the other const evaluation features in the Rust Reference at https://doc.rust-lang.org/stable/reference/const_eval.html.
There is a PR that updates this documentation to reflect the capabilities enabled by these features at https://github.com/rust-lang/reference/pull/1166.
bors [Mon, 7 Mar 2022 15:25:42 +0000 (15:25 +0000)]
Auto merge of #94690 - nnethercote:clarify-Layout-interning, r=fee1-dead
Clarify `Layout` interning.
`Layout` is another type that is sometimes interned, sometimes not, and
we always use references to refer to it so we can't take any advantage
of the uniqueness properties for hashing or equality checks.
This commit renames `Layout` as `LayoutS`, and then introduces a new
`Layout` that is a newtype around an `Interned<LayoutS>`. It also
interns more layouts than before. Previously layouts within layouts
(via the `variants` field) were never interned, but now they are. Hence
the lifetime on the new `Layout` type.
Unlike other interned types, these ones are in `rustc_target` instead of
`rustc_middle`. This reflects the existing structure of the code, which
does layout-specific stuff in `rustc_target` while `TyAndLayout` is
generic over the `Ty`, allowing the type-specific stuff to occur in
`rustc_middle`.
The commit also adds a `HashStable` impl for `Interned`, which was
needed. It hashes the contents, unlike the `Hash` impl which hashes the
pointer.
bors [Mon, 7 Mar 2022 07:29:08 +0000 (07:29 +0000)]
Auto merge of #94692 - matthiaskrgr:rollup-64p7ya7, r=matthiaskrgr
Rollup of 4 pull requests
Successful merges:
- #94636 (Check extra function arg exprs even if the fn is not C-variadic)
- #94676 (Remove unnecessary `..` patterns)
- #94681 (CTFE engine: expose misc_cast to Miri)
- #94684 (Fix rustdoc for GATs with with anonymous bound regions)
Matthias Krüger [Mon, 7 Mar 2022 05:44:02 +0000 (06:44 +0100)]
Rollup merge of #94636 - compiler-errors:issue-94599, r=davidtwco
Check extra function arg exprs even if the fn is not C-variadic
We should still call check_expr on the args that exceed the formal input ty count, so that we have expr types to emit during writeback.
Not sure where this regressed, but it wasn't due to the same root cause as #94334 I think. I thought this might've regressed in #92360, but I think that is in stable, ad the test I provided (which minimizes #94599) passes on stable in playground. Maybe it regressed in #93118.
bors [Mon, 7 Mar 2022 04:48:23 +0000 (04:48 +0000)]
Auto merge of #94272 - tavianator:readdir-reclen-for-real, r=cuviper
fs: Don't dereference a pointer to a too-small allocation
ptr::addr_of!((*ptr).field) still requires ptr to point to an
appropriate allocation for its type. Since the pointer returned by
readdir() can be smaller than sizeof(struct dirent), we need to entirely
avoid dereferencing it as that type.
`Layout` is another type that is sometimes interned, sometimes not, and
we always use references to refer to it so we can't take any advantage
of the uniqueness properties for hashing or equality checks.
This commit renames `Layout` as `LayoutS`, and then introduces a new
`Layout` that is a newtype around an `Interned<LayoutS>`. It also
interns more layouts than before. Previously layouts within layouts
(via the `variants` field) were never interned, but now they are. Hence
the lifetime on the new `Layout` type.
Unlike other interned types, these ones are in `rustc_target` instead of
`rustc_middle`. This reflects the existing structure of the code, which
does layout-specific stuff in `rustc_target` while `TyAndLayout` is
generic over the `Ty`, allowing the type-specific stuff to occur in
`rustc_middle`.
The commit also adds a `HashStable` impl for `Interned`, which was
needed. It hashes the contents, unlike the `Hash` impl which hashes the
pointer.
bors [Sun, 6 Mar 2022 22:37:54 +0000 (22:37 +0000)]
Auto merge of #94597 - nnethercote:ConstAllocation, r=fee1-dead
Introduce `ConstAllocation`.
Currently some `Allocation`s are interned, some are not, and it's very
hard to tell at a use point which is which.
This commit introduces `ConstAllocation` for the known-interned ones,
which makes the division much clearer. `ConstAllocation::inner()` is
used to get the underlying `Allocation`.
In some places it's natural to use an `Allocation`, in some it's natural
to use a `ConstAllocation`, and in some places there's no clear choice.
I've tried to make things look as nice as possible, while generally
favouring `ConstAllocation`, which is the type that embodies more
information. This does require quite a few calls to `inner()`.
The commit also tweaks how `PartialOrd` works for `Interned`. The
previous code was too clever by half, building on `T: Ord` to make the
code shorter. That caused problems with deriving `PartialOrd` and `Ord`
for `ConstAllocation`, so I changed it to build on `T: PartialOrd`,
which is slightly more verbose but much more standard and avoided the
problems.
Currently some `Allocation`s are interned, some are not, and it's very
hard to tell at a use point which is which.
This commit introduces `ConstAllocation` for the known-interned ones,
which makes the division much clearer. `ConstAllocation::inner()` is
used to get the underlying `Allocation`.
In some places it's natural to use an `Allocation`, in some it's natural
to use a `ConstAllocation`, and in some places there's no clear choice.
I've tried to make things look as nice as possible, while generally
favouring `ConstAllocation`, which is the type that embodies more
information. This does require quite a few calls to `inner()`.
The commit also tweaks how `PartialOrd` works for `Interned`. The
previous code was too clever by half, building on `T: Ord` to make the
code shorter. That caused problems with deriving `PartialOrd` and `Ord`
for `ConstAllocation`, so I changed it to build on `T: PartialOrd`,
which is slightly more verbose but much more standard and avoided the
problems.
bors [Sun, 6 Mar 2022 20:21:35 +0000 (20:21 +0000)]
Auto merge of #94679 - matthiaskrgr:rollup-9vd7w6a, r=matthiaskrgr
Rollup of 3 pull requests
Successful merges:
- #94659 (explain why shift with signed offset works the way it does)
- #94671 (fix pin doc typo)
- #94672 (Improved error message for failed bitcode load)
bors [Sun, 6 Mar 2022 18:07:11 +0000 (18:07 +0000)]
Auto merge of #94579 - tmiasko:target-features, r=nagisa
Always include global target features in function attributes
This ensures that information about target features configured with
`-C target-feature=...` or detected with `-C target-cpu=native` is
retained for subsequent consumers of LLVM bitcode.
This is crucial for linker plugin LTO, since this information is not
conveyed to the plugin otherwise.
<details><summary>Additional test case demonstrating the issue</summary>
```rust
extern crate core;
#[inline]
#[target_feature(enable = "aes")]
unsafe fn f(a: u128, b: u128) -> u128 {
use core::arch::x86_64::*;
use core::mem::transmute;
transmute(_mm_aesenc_si128(transmute(a), transmute(b)))
}
Matthias Krüger [Sun, 6 Mar 2022 14:41:26 +0000 (15:41 +0100)]
Rollup merge of #93412 - fee1-dead:improve-rustdoc-const-bounds, r=GuillaumeGomez
Improve rustdoc const bounds
- Rustdoc no longer displays `~const` in trait bounds, because it currently means nothing for stable users, and because we still haven't decided on the final syntax yet.
- Rustdoc will hide trait bounds where the trait is `Drop` AND it is `~const`, i.e. `~const Drop` bounds because it has no effect on stable users as well.
- Because of additional logic that hides the whole `where` statement where it consists of `~const Drop` bounds (so it doesn't display `struct Foo<T>() where ;` like that), bounds that have no trait e.g. `where [T; N+1]: ;` are also hidden.