Update pkg-config
I'd like to be able to cross-compile rustc in a scenario where it'd be really helpful to have cd3ccca7c3. I've done some test builds of the compiler on x86_64 linux, targeting x86_64 linux and aarch64 linux.
Add documentation about the memory layout of `UnsafeCell<T>`
The documentation for `UnsafeCell<T>` currently does not make any promises about its memory layout. This PR adds this documentation, namely that the memory layout of `UnsafeCell<T>` is the same as the memory layout of its inner `T`.
# Use case
Without this layout promise, the following cast would not be legally possible:
```rust
fn example<T>(ptr: *mut T) -> *const UnsafeCell<T> {
ptr as *const UnsafeCell<T>
}
```
A use case where this can come up involves FFI. If Rust receives a pointer over a FFI boundary which provides shared read-write access (with some form of custom synchronization), and this pointer is managed by some Rust struct with lifetime `'a`, then it would greatly simplify its (internal) API and safety contract if a `&'a UnsafeCell<T>` can be created from a raw FFI pointer `*mut T`. A lot of safety checks can be done when receiving the pointer for the first time through FFI (non-nullness, alignment, initialize uninit bytes, etc.) and these properties can then be encoded into the `&UnsafeCell<T>` type. Without this documentation guarantee, this is not legal today outside of the standard library.
# Caveats
Casting in the opposite direction is still not valid, even with this documentation change:
```rust
fn example2<T>(ptr: &UnsafeCell<T>) -> &mut T {
let t = ptr as *const UnsafeCell<T> as *mut T;
unsafe { &mut *t }
}
```
This is because the only legal way to obtain a mutable pointer to the contents of the shared reference is through [`UnsafeCell::get`](https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.get) and [`UnsafeCell::raw_get`](https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.raw_get). Although there might be a desire to also make this legal at some point in the future, that part is outside the scope of this PR. Also see this relevant [Zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/136281-t-lang.2Fwg-unsafe-code-guidelines/topic/transmuting.20.26.20-.3E.20.26mut).
# Alternatives
Instead of adding a new documentation promise, it's also possible to add a new method to `UnsafeCell<T>` with signature `pub fn from_ptr_bikeshed(ptr: *mut T) -> *const UnsafeCell<T>` which indirectly only allows one-way casting to `*const UnsafeCell<T>`.
std: use `sync::Mutex` for internal statics
Since `sync::Mutex` is now `const`-constructible, it can be used for internal statics, removing the need for `sys_common::StaticMutex`. This adds some extra allocations on platforms which need to box their mutexes (currently SGX and some UNIX), but these will become unnecessary with the lock improvements tracked in #93740.
I changed the program argument implementation on Hermit, it does not need `Mutex` but can use atomics like some UNIX systems (ping `@mkroening` `@stlankes).`
Get rid of `rustc_query_description!`
**I am not entirely sure whether this is an improvement and would like to get your feedback on it.**
Helps with #96524.
Queries can provide an arbitrary expression for their description and their caching behavior. Before, these expressions where stored in a `rustc_query_description` macro emitted by the `rustc_queries` macro, and then used in `rustc_query_impl` to fill out the methods for the `QueryDescription` trait.
Instead, we now emit two new modules from `rustc_queries` containing the functions with the expressions. `rustc_query_impl` calls these functions now instead of invoking the macro.
Since we are now defining some of the functions in `rustc_middle::query`, we now need all the imports for the key types mthere as well.
r? `@cjgillot`
Rollup of 6 pull requests
Successful merges:
- #102773 (Use semaphores for thread parking on Apple platforms)
- #102884 (resolve: Some cleanup, asserts and tests for lifetime ribs)
- #102954 (Add missing checks for `doc(cfg_hide(...))`)
- #102998 (Drop temporaries created in a condition, even if it's a let chain)
- #103003 (Fix `suggest_floating_point_literal` ICE)
- #103041 (Update cargo)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Update cargo
12 commits in b8f30cb23c4e5f20854a4f683325782b7cff9837..b332991a57c9d055f1864de1eed93e2178d49440 2022-10-10 19:16:06 +0000 to 2022-10-13 22:05:28 +0000
- Differentiate the warning when an alias (built-in or user-defined) shadows an external subcommand (rust-lang/cargo#11170)
- chore: Update tests for latest clap (rust-lang/cargo#11235)
- feat(publish): Support 'publish.timeout' config behind '-Zpublish-timeout' (rust-lang/cargo#11230)
- Add missing edition (rust-lang/cargo#11231)
- doc(profiles): add module level doc (rust-lang/cargo#11219)
- refactor(publish): Clarify which SourceId is being used (rust-lang/cargo#11216)
- Add new SourceKind::SparseRegistry to differentiate sparse registries (rust-lang/cargo#11209)
- Fix deadlock when build scripts are waiting for input on stdin (rust-lang/cargo#11205)
- refactor: New variant `FeaturesFor::ArtifactDep` (rust-lang/cargo#11184)
- Fix rustdoc warning about unclosed HTML tag (rust-lang/cargo#11221)
- refactor(tests): Prepare for wait-for-publish test changes (rust-lang/cargo#11210)
- Add configuration option for controlling crates.io protocol (rust-lang/cargo#11215)
Drop temporaries created in a condition, even if it's a let chain
Fixes#100513.
During the lowering from AST to HIR we wrap expressions acting as conditions in a `DropTemps` expression so that any temporaries created in the condition are dropped after the condition is executed. Effectively this means we transform
```rust
if Some(1).is_some() { .. }
```
into (roughly)
```rust
if { let _t = Some(1).is_some(); _t } { .. }
```
so that if we create any temporaries, they're lifted into the new scope surrounding the condition, so for example something along the lines of
```rust
if { let temp = Some(1); let _t = temp.is_some(); _t }.
```
Before this PR, if the condition contained any let expressions we would not introduce that new scope, instead leaving the condition alone. This meant that in a let-chain like
```rust
if get_drop("first").is_some() && let None = get_drop("last") {
println!("second");
} else { .. }
```
the temporary created for `get_drop("first")` would be lifted into the _surrounding block_, which caused it to be dropped after the execution of the entire `if` expression.
After this PR, we wrap everything but the `let` expression in terminating scopes. The upside to this solution is that it's minimally invasive, but the downside is that in the worst case, an expression with `let` exprs interspersed like
```rust
if get_drop("first").is_some()
&& let Some(_a) = get_drop("fifth")
&& get_drop("second").is_some()
&& let Some(_b) = get_drop("fourth") { .. }
```
gets _multiple_ new scopes, roughly
```rust
if { let _t = get_drop("first").is_some(); _t }
&& let Some(_a) = get_drop("fifth")
&& { let _t = get_drop("second").is_some(); _t }
&& let Some(_b) = get_drop("fourth") { .. }
```
so instead of all of the temporaries being dropped at the end of the entire condition, they will be dropped right after they're evaluated (before the subsequent `let` expr). So while I'd say the drop behavior around let-chains is _less_ surprising after this PR, it still might not exactly match what people might expect.
For tests, I've just extended the drop order tests added in #100526. I'm not sure if that's the best way to go about it, though, so suggestions are welcome.
Add missing checks for `doc(cfg_hide(...))`
Part of #43781.
The `doc(cfg_hide(...))` attribute can only be used at the crate level and takes a list of attributes as argument.
r? ```@Manishearth```
Use semaphores for thread parking on Apple platforms
Currently we use a mutex-condvar pair for thread parking on Apple systems. Unfortunately, `pthread_cond_timedwait` uses the real-time clock for measuring time, which causes problems when the system time changes. The parking implementation in this PR uses a semaphore instead, which measures monotonic time by default, avoiding these issues. As a further benefit, this has the potential to improve performance a bit, since `unpark` does not need to wait for a lock to be released.
Since the Mach semaphores are poorly documented (I could not find availability or stability guarantees for instance), this uses a [dispatch semaphore](https://developer.apple.com/documentation/dispatch/dispatch_semaphore?language=objc) instead. While it adds a layer of indirection (it uses Mach semaphores internally), the overhead is probably negligible.
Tested on macOS 12.5.
r? ``````@thomcc``````
Make `dyn*` casts into a coercion, allow `dyn*` upcasting
I know that `dyn*` is likely not going to be a feature exposed to surface Rust, but this makes it slightly more ergonomic to write tests for these types anyways. ... and this was just fun to implement anyways.
1. Make `dyn*` into a coercion instead of a cast
2. Enable `dyn*` upcasting since we basically get it for free
3. Simplify some of the cast checking code since we're using the coercion path now
r? `@eholk` but feel free to reassign
cc `@nikomatsakis` and `@tmandry` who might care about making `dyn*` casts into a coercion
Correctly handle path stability for 'use tree' items
PR #95956 started checking the stability of path segments.
However, this was not applied to 'use tree' items
(e.g. 'use some::path::{ItemOne, ItemTwo}') due to the way
that we desugar these items in HIR lowering.
This PR modifies 'use tree' lowering to preserve resolution
information, which is needed by stability checking.
Add `IsTerminal` trait to determine if a descriptor or handle is a terminal
The UNIX implementation uses `isatty`. The Windows implementation uses
the same logic the `atty` crate uses, including the hack needed to
detect msys terminals.
Implement this trait for `Stdin`/`Stdout`/`Stderr`/`File` on all
platforms. On Unix, implement it for `BorrowedFd`/`OwnedFd`. On Windows,
implement it for `BorrowedHandle`/`OwnedHandle`.
Based on https://github.com/rust-lang/rust/pull/91121
Co-authored-by: Matt Wilkinson <mattwilki17@gmail.com>
Rather than referencing a slice's pointer and then creating a new slice
with a longer length, offset from the base structure pointer instead.
This makes some choices of Rust semantics happier.
The UNIX and WASI implementations use `isatty`. The Windows
implementation uses the same logic the `atty` crate uses, including the
hack needed to detect msys terminals.
Implement this trait for `File` and for `Stdin`/`Stdout`/`Stderr` and
their locked counterparts on all platforms. On UNIX and WASI, implement
it for `BorrowedFd`/`OwnedFd`. On Windows, implement it for
`BorrowedHandle`/`OwnedHandle`.
Based on https://github.com/rust-lang/rust/pull/91121
Co-authored-by: Matt Wilkinson <mattwilki17@gmail.com>
Fix `Duration::{try_,}from_secs_f{32,64}(-0.0)`
Make `Duration::{try_,}from_secs_f{32,64}(-0.0)` return `Duration::ZERO` (as they did before #90247) instead of erroring/panicking.
I'll update this PR to remove the `#![feature(duration_checked_float)]` if #102271 is merged before this PR.
Tracking issue for `try_from_secs_f{32,64}`: #83400
Queries can provide an arbitrary expression for their description and
their caching behavior. Before, these expressions where stored in a
`rustc_query_description` macro emitted by the `rustc_queries` macro,
and then used in `rustc_query_impl` to fill out the methods for the
`QueryDescription` trait.
Instead, we now emit two new modules from `rustc_queries` containing the
functions with the expressions. `rustc_query_impl` calls these functions
now instead of invoking the macro.
Since we are now defining some of the functions in
`rustc_middle::query`, we now need all the imports for the key types
there as well.
sync thread_local key conditions exactly with what the macro uses
This makes the `cfg` in `mod.rs` syntactically the same as those in `local.rs`.
I don't think this should actually change anything, but seems better to be consistent?
I looked into this due to https://github.com/rust-lang/rust/issues/102549, but this PR would make it *less* likely that `__OsLocalKeyInner` is going to get provided, so this cannot help with that issue.
r? `@thomcc`
Detect and reject out-of-range integers in format string literals
Until now out-of-range integers in format string literals were silently ignored. They wrapped around to zero at usize::MAX, producing unexpected results.
When using debug builds of rustc, such integers in format string literals even cause an 'attempt to add with overflow' panic in rustc.
Fix this by producing an error diagnostic for integers in format string literals which do not fit into usize.
Fixes#102528
Rollup of 8 pull requests
Successful merges:
- #102847 (impl AsFd and AsRawFd for io::{Stdin, Stdout, Stderr}, not the sys versions)
- #102856 (Only test duplicate inherent impl items in a single place)
- #102914 (Migrate css highlight without change)
- #102938 (Move some tests to more reasonable directories)
- #103015 (fix a typo)
- #103018 (More dupe word typos)
- #103025 (rustdoc: remove unused CSS `.search-container > *`)
- #103031 (Suppress irrefutable let patterns lint for prefixes in match guards)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Suppress irrefutable let patterns lint for prefixes in match guards
In match guards, irrefutable prefixes might use the bindings created by the match pattern. Ideally, we check for this, but we can do the next best thing and just not lint for irrefutable prefixes in match guards.
Fixes#98361
rustdoc: remove unused CSS `.search-container > *`
The two items it was really intended to target were the buttons, and those both need to have the style set directly on them anyway because the buttons are both child elements of wrappers.
6b3ede3f7b/src/librustdoc/html/static/css/rustdoc.css (L1406-L1411)
More dupe word typos
I only picked those changes (from the regex search) that I am pretty certain doesn't change meaning and is just a typo fix. Do correct me if any fix is undesirable and I can revert those. Thanks.
