Make slice comparisons const
This needed a fix for `derive_const`, too, as it wasn't usable in libcore anymore as trait impls need const stability attributes. I think we can't use the same system as normal trait impls while `const_trait_impl` is still unstable.
r? ```@fee1-dead```
cc rust-lang/rust#143800
Linting public reexport of private dependencies
Part of public/private dependencies rust-lang/rust#44663
Partially addresses rust-lang/rust#71043
I'm adding a warning for reexports of private dependencies into `rustc_resolve`. I get that this should not be a warning, but should instead be a lint to be controlled by the feature gate, but I did not figure out how exactly to do that at that point. I tried doing the same thing as is done in `rustc_privacy`, but the linting system is not ready yet as far as I understand the error I got, so I made a warning for now instead. Some guidance on how to emit lints with `dcx` would be appreciated.
This also sets the `std_detect` crate as a public dependency of `std` because some macros are reexported from there. I did not check closer, but the other option may be to allow the specific reexports instead.
Trim `BorrowedCursor` API
This PR removes some method from the unstable `BorrowedCursor` type. A rational for each change can be found in the message of each commit.
I don't think that an ACP is required for this, please tell me if it is not the case.
Cc rust-lang/rust#78485rust-lang/rust#117693
UWP: link ntdll functions using raw-dylib
Lazy loading isn't necessary so there's no need for the added complexity and overhead. However, it may be that people using UWP rust libraries don't have the necessary import libraries linked by Visual Studio so this uses raw-dylib, which allows linking to DLL functions without having an import library. This is a somewhat temporary situation as raw-dylib is intended to eventually be the default for all imports. When that happens, this special case can be removed.
Closesrust-lang/rust#143530
Add experimental `backtrace-trace-only` std feature
This experimentally allows building std with backtrace but without symbolisation. It does not affect stable and requires build-std to use. This doesn't change the backtrace crate itself so relies on the optimizer to remove the unused parts.
Example usage:
```toml
# .cargo/config.toml
[unstable]
build-std = ["core", "alloc", "panic_unwind", "std"]
build-std-features = ["backtrace", "backtrace-trace-only", "panic-unwind"]
```
```toml
# Cargo.toml
[profile.release]
opt-level = 3
lto = "thin"
codegen-units = 1
```
Ideally we should split the backtrace feature into `backtrace-trace` and `backtrace-symbolize` (with the latter dependent on the former) because Cargo features tend to work better when they're positive rather than negative. But I'm keen for this experiment not to break existing users.
cc ``@joshtriplett``
Updates to random number generation APIs
Updates based on discussions about random number generation.
- Add comment on `RandomSource::fill_bytes` about multiple calls, to allow
efficient implementations for random sources that generate a word at a time.
- Drop the `Random` trait in favor of `Distribution<T>`, which will let people
make calls like random(1..=6), and which allows for future expansion to
non-uniform distributions, as well as floating-point. (For now, this is only
implemented for `RangeFull`, to get the interface in place. Subsequent PRs
will implement it for other range types.)
Use zero for initialized Once state
By re-labeling which integer represents which internal state for `Once` we can ensure that the initialized state is the all-zero state. This is beneficial because some CPU architectures (such as Arm) have specialized instructions to specifically branch on non-zero, and checking for the initialized state is by far the most important operation.
As an example, take this:
```rust
use std::sync::atomic::{AtomicU32, Ordering};
const INIT: u32 = 3;
#[inline(never)]
#[cold]
pub fn slow(state: &AtomicU32) {
state.store(INIT, Ordering::Release);
}
pub fn ensure_init(state: &AtomicU32) {
if state.load(Ordering::Acquire) != INIT {
slow(state)
}
}
```
If `INIT` is 3 (as is currently the state for `Once`), we see the following assembly on `aarch64-apple-darwin`:
```asm
example::ensure_init::h332061368366e313:
ldapr w8, [x0]
cmp w8, #3
b.ne LBB1_2
ret
LBB1_2:
b example::slow::ha042bd6a4f33724e
```
By changing the `INIT` state to zero we get the following:
```asm
example::ensure_init::h332061368366e313:
ldapr w8, [x0]
cbnz w8, LBB1_2
ret
LBB1_2:
b example::slow::ha042bd6a4f33724e
```
So this PR saves 1 instruction every time a `LazyLock` gets accessed on platforms such as these.
std: move NuttX to use arc4random for random number generation
arc4random support in libc merged in https://github.com/rust-lang/libc/pull/4464, so:
* Move `target_os = "nuttx"` from unix_legacy to arc4random section
* This aligns NuttX with other POSIX-compliant systems that support arc4random
* Improves random number generation quality on NuttX by using the system's built-in arc4random implementation instead of legacy fallback methods
NuttX supports arc4random_buf which provides better entropy and security compared to the legacy random number generation methods.
Rollup of 9 pull requests
Successful merges:
- rust-lang/rust#143403 (Port several trait/coherence-related attributes the new attribute system)
- rust-lang/rust#143633 (fix: correct assertion to check for 'noinline' attribute presence before removal)
- rust-lang/rust#143647 (Clarify and expand documentation for std::sys_common dependency structure)
- rust-lang/rust#143716 (compiler: doc/comment some codegen-for-functions interfaces)
- rust-lang/rust#143747 (Add target maintainer information for aarch64-unknown-linux-musl)
- rust-lang/rust#143759 (Fix typos in function names in the `target_feature` test)
- rust-lang/rust#143767 (Bump `src/tools/x` to Edition 2024 and some cleanups)
- rust-lang/rust#143769 (Remove support for SwitchInt edge effects in backward dataflow)
- rust-lang/rust#143770 (build-helper: clippy fixes)
r? `@ghost`
`@rustbot` modify labels: rollup
Clarify and expand documentation for std::sys_common dependency structure
This PR makes a minor improvement to the module-level documentation of std::sys_common:
Replaces the lowercase “dag” with the more standard and explicit form “DAG (Directed Acyclic Graph)” for clarity.
This will let people make calls like random(1..=6), and allows for
future expansion to non-uniform distributions, as well as
floating-point.
For now, this is only implemented for `RangeFull`, to get the interface
in place. Subsequent commits will implement it for other range types.
* Move `target_os = "nuttx"` from unix_legacy to arc4random section
* This aligns NuttX with other POSIX-compliant systems that support arc4random
* Improves random number generation quality on NuttX by using the system's
built-in arc4random implementation instead of legacy fallback methods
NuttX supports arc4random_buf which provides better entropy and security
compared to the legacy random number generation methods.
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
rust: library: Add `setsid` method to `CommandExt` trait
Add a setsid method to the CommandExt trait so that callers can create a process in a new session and process group whilst still using the POSIX spawn fast path.
Tracking issue: rust-lang/rust#105376
ACP: https://github.com/rust-lang/libs-team/issues/184
This PR was previously submitted by ``@HarveyHunt`` (whom I marked as Co-Author in the commit message) in rust-lang/rust#105377. However that PR went stale.
I applied the [suggestion](231d19fcbf (r1893457943)) to change the function signature to `fn setsid(&mut self, setsid: bool) -> &mut Command`.
Add a setsid method to the CommandExt trait so that callers can create
a process in a new session and process group whilst still using the
POSIX spawn fast path.
Co-Authored-By: Harvey Hunt <harveyhunt@fb.com>
The clock_nanosleep support is there to allow code using `sleep_until`
to run under Miri. Therefore the implementation is minimal.
- Only the clocks REALTIME and MONOTONIC are supported. The first is supported simply
because it was trivial to add not because it was needed for sleep_until.
- The only supported flag combinations are no flags or TIMER_ABSTIME only.
If an unsupported flag combination or clock is passed in this throws
unsupported.
Using clock nanosleep leads to more accurate sleep times on platforms
where it is supported.
To enable using clock_nanosleep this makes `sleep_until` platform
specific. That unfortunatly requires identical placeholder
implementations for the other platforms (windows/mac/wasm etc).
we will land platform specific implementations for those later. See the
`sleep_until` tracking issue.
This requires an accessors for the Instant type. As that accessor is only
used on the platforms that have clock_nanosleep it is marked as allow_unused.
32bit time_t targets do not use clock_nanosleep atm, they instead rely
on the same placeholder as the other platforms. We could make them
use clock_nanosleep too in the future using `__clock_nanosleep_time64`.
__clock_nanosleep_time64 is documented at:
https://www.gnu.org/software/libc/manual/html_node/64_002dbit-time-symbol-handling.html
Make __rust_alloc_error_handler_should_panic a function
Fixesrust-lang/rust#143253
`__rust_alloc_error_handler_should_panic` is a static but was being exported as a function.
For most targets this doesn't matter, but Arm64EC Windows uses different decorations for exported variables vs functions, hence it fails to link when `-Z oom=abort` is enabled.
We've had issues in the past with statics like this (see rust-lang/rust#141061) but the tldr; is that Arm64EC needs symbols correctly exported as either a function or data, and data MUST and MUST ONLY be marked `dllimport` when the symbol is being imported from another binary, which is non-trivial to calculate for these compiler-generated statics.
So, instead, the easiest thing to do is to make `__rust_alloc_error_handler_should_panic` a function instead.
Since `__rust_alloc_error_handler_should_panic` isn't involved in any linking shenanigans, I've marked it as `AlwaysInline` with the hopes that the various backends will see that it is just returning a constant and perform the same optimizations as the previous implementation.
r? `@bjorn3`
setup typos check in CI
This allows to check typos in CI, currently for compiler only (to reduce commit size with fixes). With current setup, exclude list is quite short, so it worth trying?
Also includes commits with actual typo fixes.
MCP: https://github.com/rust-lang/compiler-team/issues/817
typos check currently turned for:
* ./compiler
* ./library
* ./src/bootstrap
* ./src/librustdoc
After merging, PRs which enables checks for other crates (tools) can be implemented too.
Found typos will **not break** other jobs immediately: (tests, building compiler for perf run). Job will be marked as red on completion in ~ 20 secs, so you will not forget to fix it whenever you want, before merging pr.
Check typos: `python x.py test tidy --extra-checks=spellcheck`
Apply typo fixes: `python x.py test tidy --extra-checks=spellcheck:fix` (in case if there only 1 suggestion of each typo)
Current fail in this pr is expected and shows how typo errors emitted. Commit with error will be removed after r+.
