Replace `try_reserve_exact` with `try_with_capacity` in `std::fs::read`
This change restores the previous behavior prior to #117925. That PR was made to handle OOM errors that turn into a panic with `Vec::with_capacity`. `try_reserve_exact` was used for that since there was no `try_with_capacity` method at the time. It was added later in #120504. I think it'd a better fit here.
fix data race in ReentrantLock fallback for targets without 64bit atomics
See [Zulip](https://rust-lang.zulipchat.com/#narrow/channel/269128-miri/topic/reentrant.20lock.20failure.20on.20musl) for details: the address used to identify a thread might get lazily allocated inside `tls_addr()`, so if we call that *after* doing the `tls_addr.load()` it is too late to establish synchronization with prior threads that used the same address -- the `load()` thus races with the `store()` by that prior thread, and might hence see outdated values, and then the entire logic breaks down.
r? `@joboet`
std: stop using TLS in signal handler
TLS is not async-signal-safe, making its use in the signal handler used to detect stack overflows unsound (c.f. #133698). POSIX however lists two thread-specific identifiers that can be obtained in a signal handler: the current `pthread_t` and the address of `errno`. Since `pthread_equal` is not AS-safe, `pthread_t` should be considered opaque, so for our purposes, `&errno` is the only option. This however works nicely: we can use the address as a key into a map that stores information for each thread. This PR uses a `BTreeMap` protected by a spin lock to hold the guard page address and thread name and thus fixes#133698.
Remove #![feature(let_chains)] from library and src/librustdoc
PR https://github.com/rust-lang/rust/pull/132833 has stabilized the `let_chains` feature. This PR removes the last occurences from the library, the compiler, and librustdoc (also because #140887 missed the conditional in one of the crates as it was behind the "rustc" feature).
We keep `core` as exercise for the future as updating it is non-trivial (see PR thread).
Initial implementation of `core_float_math`
Since [1], `compiler-builtins` makes a certain set of math symbols
weakly available on all platforms. This means we can begin exposing some
of the related functions in `core`, so begin this process here.
It is not possible to provide inherent methods in both `core` and `std`
while giving them different stability gates, so standalone functions are
added instead. This provides a way to experiment with the functionality
while unstable; once it is time to stabilize, they can be converted to
inherent.
For `f16` and `f128`, everything is unstable so we can move the inherent
methods.
The following are included to start:
* floor
* ceil
* round
* round_ties_even
* trunc
* fract
* mul_add
* div_euclid
* rem_euclid
* powi
* sqrt
* abs_sub
* cbrt
These mirror the set of functions that we have in `compiler-builtins`
since [1], with the exception of `powi` that has been there longer.
Details for each of the changes is in the commit messages.
Tracking issue: https://github.com/rust-lang/rust/issues/137578
[1]: https://github.com/rust-lang/compiler-builtins/pull/763
try-job: aarch64-gnu
tru-job: armhf-gnu
try-job: i686-msvc-1
try-job: test-various
try-job: x86_64-mingw-1
try-job: x86_64-mingw-2
deduplicate abort implementations
Currently, the code for process aborts is duplicated across `panic_abort` and `std`. This PR uses `#[rustc_std_internal_symbol]` to make the `std` implementation available to `panic_abort` via the linker, thereby deduplicating the code.
Currently, the code for process aborts is duplicated across `panic_abort` and `std`. This PR uses `#[rustc_std_internal_symbol]` to make the `std` implementation available to `panic_abort` via the linker, thereby deduplicating the code.
Since [1], `compiler-builtins` makes a certain set of math symbols
weakly available on all platforms. This means we can begin exposing some
of the related functions in `core`, so begin this process here.
It is not possible to provide inherent methods in both `core` and `std`
while giving them different stability gates, so standalone functions are
added instead. This provides a way to experiment with the functionality
while unstable; once it is time to stabilize, they can be converted to
inherent.
For `f16` and `f128`, everything is unstable so we can move the inherent
methods.
The following are included to start:
* floor
* ceil
* round
* round_ties_even
* trunc
* fract
* mul_add
* div_euclid
* rem_euclid
* powi
* sqrt
* abs_sub
* cbrt
These mirror the set of functions that we have in `compiler-builtins`
since [1].
Tracking issue: https://github.com/rust-lang/rust/issues/137578
[1]: https://github.com/rust-lang/compiler-builtins/pull/763
Implement (part of) ACP 429: add `DerefMut` to `Lazy[Cell/Lock]`
`DerefMut` is instantly stable, as a trait impl. That means this needs an FCP.
``@rustbot`` label +needs-fcp
https://github.com/rust-lang/libs-team/issues/429
[win][arm64] Disable std::fs tests that require symlinks
While trying to get the aarch64-msvc build working correctly (#140136), various tests in `std::fs` were failing as the Arm64 Windows runner image we are using does not have Developer Mode enabled, thus it cannot create symlinks.
I've [filed a request to get Developer Mode enabled](https://github.com/actions/partner-runner-images/issues/94), but in the meantime I've disabled the relevant tests on Arm64 Windows.
collect all Fuchsia bindings into the `fuchsia` module
The Fuchsia bindings are currently spread out across multiple modules in `sys/pal/unix` leading to unnecessary duplication. This PR moves all of these definitions into `sys::pal::unix::fuchsia` and additionally:
* deduplicates the definitions
* makes the error names consistent
* marks `zx_thread_self` and `zx_clock_get_monotonic` as safe extern functions
* removes unused items (there's no need to maintain these bindings if we're not going to use them)
* removes the documentation for the definitions (contributors should always consult the platform documentation, duplicating that here is just an extra maintenance burden)
`@rustbot` ping fuchsia
std: get rid of `sys_common::process`
Move the public `CommandEnvs` into the `process` module (and make it a wrapper type for an internal iterator type) and everything else into `sys::process` as per #117276.
Something went wrong with a force push, so I can't reopen#139020. This is unchanged from that PR, apart from a rebase.
r? ```@thomcc```
TLS is not async-signal-safe, making its use in the signal handler used to detect stack overflows unsound (c.f. #133698). POSIX however lists two thread-specific identifiers that can be obtained in a signal handler: the current `pthread_t` and the address of `errno`. Since `pthread_equal` is not AS-safe, `pthread_t` should be considered opaque, so for our purposes, `&errno` is the only option. This however works nicely: we can use the address as a key into a map that stores information for each thread. This PR uses a `BTreeMap` protected by a spin lock to hold the guard page address and thread name and thus fixes#133698.
The Fuchsia bindings are currently spread out across multiple modules in `sys/pal/unix` leading to unnecessary duplication. This PR moves all of these definitions into `sys::pal::unix::fuchsia` and additionally:
* deduplicates the definitions
* makes the error names consistent
* marks some extern functions as safe
* removes unused items (there's no need to maintain these bindings if we're not going to use them)
* removes the documentation for the definitions (contributors should always consult the platform documentation, duplicating that here is just an extra maintenance burden)
doc(std): fix typo lchown -> lchmod
chown is irrelevant here, as this function does not affect file ownership. chmod is the correct function to reference here.
Use present indicative tense in std::io::pipe() API docs
The inline documentation for all other free functions in the `std::io` module use the phrase "creates a" instead of "create a", except for the currently nightly-only `std::io::pipe()` function. This commit updates the text to align with the predominant wording in the `std::io` module.
I recognize this PR is quite a minuscule nitpick, so feel free to ignore and close if you disagree and/or there are bigger fish to fry. Thanks in advance! 😄
Relates to https://github.com/rust-lang/rust/issues/127154.
Avoid redundant WTF-8 checks in `PathBuf`
Eliminate checks for WTF-8 boundaries in `PathBuf::set_extension` and `add_extension`, where joining WTF-8 surrogate halves is impossible. Don't convert the `str` to `OsStr`, because `OsString::push` specializes to skip the joining when given strings.
To assist in this, mark the internal methods `OsString::truncate` and `extend_from_slice` as `unsafe` to communicate their safety invariants better than with module privacy.
Similar to #137777.
cc `@joboet` `@ChrisDenton`
Delegate to inner `vec::IntoIter` from `env::ArgsOs`
Delegate from `std::env::ArgsOs` to the methods of the inner platform-specific iterators, when it would be more efficient than just using the default methods of its own impl. Most platforms use `vec::IntoIter` as the inner type, so prioritize delegating to the methods it provides.
`std::env::Args` is implemented atop `std::env::ArgsOs` and performs UTF-8 validation with a panic for invalid data. This is a visible effect which users certainly rely on, so we can't skip any arguments. Any further iterator methods would skip some elements, so no change is needed for that type.
Add `#[inline]` for any methods which simply wrap the inner iterator.
Clarify `async` block behaviour
Adds some documentation for control flow behaviour pertaining to `return` and `?` within `async` blocks. Fixes (or at least improves) #101444.
r? rust-lang/docs
std: use the address of `errno` to identify threads in `unique_thread_exit`
Getting the address of `errno` should be just as cheap as `pthread_self()` and avoids having to use the expensive `Mutex` logic because it always results in a pointer.
