Move `doc(primitive)` future incompat warning to `invalid_doc_attributes`
Fixes#88070.
It's been a while since this was turned into a "future incompatible lint" so I think we can now turn it into a hard error without problem.
r? `@jyn514`
Insert alignment checks for pointer dereferences when debug assertions are enabled
Closes https://github.com/rust-lang/rust/issues/54915
- [x] Jake tells me this sounds like a place to use `MirPatch`, but I can't figure out how to insert a new basic block with a new terminator in the middle of an existing basic block, using `MirPatch`. (if nobody else backs up this point I'm checking this as "not actually a good idea" because the code looks pretty clean to me after rearranging it a bit)
- [x] Using `CastKind::PointerExposeAddress` is definitely wrong, we don't want to expose. Calling a function to get the pointer address seems quite excessive. ~I'll see if I can add a new `CastKind`.~ `CastKind::Transmute` to the rescue!
- [x] Implement a more helpful panic message like slice bounds checking.
r? `@oli-obk`
Refactor glibc time64 support, riscv32 always has 64-bit `time_t`
Refactor existing support for 64-bit `time_t` on 32-bit glibc platforms, as riscv32 `time_t` is 64-bit by default. Split out of #109773.
Improve documentation for str::replace() and str::replacen()
Currently, to know what the function will return when the pattern doesn't match, the docs require the reader to understand the implementation detail and mentally evaluate or run the example code. It is not immediately clear.
This PR makes it more explicit so the reader can quickly find the information.
Rollup of 7 pull requests
Successful merges:
- #106985 (Enhanced doucmentation of binary search methods for `slice` and `VecDeque` for unsorted instances)
- #109509 (compiletest: Don't allow tests with overlapping prefix names)
- #109719 (RELEASES: Add "Only support Android NDK 25 or newer" to 1.68.0)
- #109748 (Don't ICE on `DiscriminantKind` projection in new solver)
- #109749 (Canonicalize float var as float in new solver)
- #109761 (Drop binutils on powerpc-unknown-freebsd)
- #109766 (Fix title for openharmony.md)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Enhanced doucmentation of binary search methods for `slice` and `VecDeque` for unsorted instances
Fixes#106746. Issue #106746 raises the concern that the binary search methods for slices and deques aren't explicit enough about the fact that they are only applicable to sorted slices/deques. I changed the explanation for these methods. I took the relatively harsh description of the behaviour of binary search on unsorted collections ("unspecified and meaningless") from the description of the [`partition_point`](https://doc.rust-lang.org/std/primitive.slice.html#method.partition_point) method:
> If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.
Partial stabilization of `once_cell`
This PR aims to stabilize a portion of the `once_cell` feature:
- `core::cell::OnceCell`
- `std::cell::OnceCell` (re-export of the above)
- `std::sync::OnceLock`
This will leave `LazyCell` and `LazyLock` unstabilized, which have been moved to the `lazy_cell` feature flag.
Tracking issue: https://github.com/rust-lang/rust/issues/74465 (does not fully close, but it may make sense to move to a new issue)
Future steps for separate PRs:
- ~~Add `#[inline]` to many methods~~ #105651
- Update cranelift usage of the `once_cell` crate
- Update rust-analyzer usage of the `once_cell` crate
- Update error messages discussing once_cell
## To be stabilized API summary
```rust
// core::cell (in core/cell/once.rs)
pub struct OnceCell<T> { .. }
impl<T> OnceCell<T> {
pub const fn new() -> OnceCell<T>;
pub fn get(&self) -> Option<&T>;
pub fn get_mut(&mut self) -> Option<&mut T>;
pub fn set(&self, value: T) -> Result<(), T>;
pub fn get_or_init<F>(&self, f: F) -> &T where F: FnOnce() -> T;
pub fn into_inner(self) -> Option<T>;
pub fn take(&mut self) -> Option<T>;
}
impl<T: Clone> Clone for OnceCell<T>;
impl<T: Debug> Debug for OnceCell<T>
impl<T> Default for OnceCell<T>;
impl<T> From<T> for OnceCell<T>;
impl<T: PartialEq> PartialEq for OnceCell<T>;
impl<T: Eq> Eq for OnceCell<T>;
```
```rust
// std::sync (in std/sync/once_lock.rs)
impl<T> OnceLock<T> {
pub const fn new() -> OnceLock<T>;
pub fn get(&self) -> Option<&T>;
pub fn get_mut(&mut self) -> Option<&mut T>;
pub fn set(&self, value: T) -> Result<(), T>;
pub fn get_or_init<F>(&self, f: F) -> &T where F: FnOnce() -> T;
pub fn into_inner(self) -> Option<T>;
pub fn take(&mut self) -> Option<T>;
}
impl<T: Clone> Clone for OnceLock<T>;
impl<T: Debug> Debug for OnceLock<T>;
impl<T> Default for OnceLock<T>;
impl<#[may_dangle] T> Drop for OnceLock<T>;
impl<T> From<T> for OnceLock<T>;
impl<T: PartialEq> PartialEq for OnceLock<T>
impl<T: Eq> Eq for OnceLock<T>;
impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceLock<T>;
unsafe impl<T: Send> Send for OnceLock<T>;
unsafe impl<T: Sync + Send> Sync for OnceLock<T>;
impl<T: UnwindSafe> UnwindSafe for OnceLock<T>;
```
No longer planned as part of this PR, and moved to the `rust_cell_try` feature gate:
```rust
impl<T> OnceCell<T> {
pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E> where F: FnOnce() -> Result<T, E>;
}
impl<T> OnceLock<T> {
pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E> where F: FnOnce() -> Result<T, E>;
}
```
I am new to this process so would appreciate mentorship wherever needed.
Use `getentropy()` instead of `/dev/urandom` on Emscripten
`/dev/urandom` is usually available on Emscripten, except when using
the special `NODERAWFS` filesystem backend, which replaces all normal
filesystem access with direct Node.js operations.
Since this filesystem backend directly access the filesystem on the
OS, it is not recommended to depend on `/dev/urandom`, especially
when trying to run the Wasm binary on OSes that are not Unix-based.
This can be considered a non-functional change, since Emscripten
implements `/dev/urandom` in the same way as `getentropy()` when not
linking with `-sNODERAWFS`.
Remove ~const from alloc
There is currently an effort underway to stop using `~const Trait`, temporarily, so as to refactor the logic underlying const traits with relative ease. This means it has to go from the standard library, as well.
I have taken the initial step of just removing these impls from alloc, as removing them from core is a much more tangled task. In addition, all of these implementations are one more-or-less logically-connected group, so reverting their deconstification as a group seems like it will also be sensible.
r? `@fee1-dead`
Use random `HashMap` keys on Hermit
Initializing the keys with random data provided by the libOS avoids HashDOS attacks and similar issues.
CC `@stlankes`
Support TLS access into dylibs on Windows
This allows access to `#[thread_local]` in upstream dylibs on Windows by introducing a MIR shim to return the address of the thread local. Accesses that go into an upstream dylib will call the MIR shim to get the address of it.
`convert_tls_rvalues` is introduced in `rustc_codegen_ssa` which rewrites MIR TLS accesses to dummy calls which are replaced with calls to the MIR shims when the dummy calls are lowered to backend calls.
A new `dll_tls_export` target option enables this behavior with a `false` value which is set for Windows platforms.
This fixes https://github.com/rust-lang/rust/issues/84933.
Rollup of 8 pull requests
Successful merges:
- #91793 (socket ancillary data implementation for FreeBSD (from 13 and above).)
- #92284 (Change advance(_back)_by to return the remainder instead of the number of processed elements)
- #102472 (stop special-casing `'static` in evaluation)
- #108480 (Use Rayon's TLV directly)
- #109321 (Erase impl regions when checking for impossible to eagerly monomorphize items)
- #109470 (Correctly substitute GAT's type used in `normalize_param_env` in `check_type_bounds`)
- #109562 (Update ar_archive_writer to 0.1.3)
- #109629 (remove obsolete `givens` from regionck)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Add a builtin `FnPtr` trait that is implemented for all function pointers
r? `@ghost`
Rebased version of https://github.com/rust-lang/rust/pull/99531 (plus adjustments mentioned in the PR).
If perf is happy with this version, I would like to land it, even if the diagnostics fix in 9df8e1befb5031a5bf9d8dfe25170620642d3c59 only works for `FnPtr` specifically, and does not generally improve blanket impls.
Change advance(_back)_by to return the remainder instead of the number of processed elements
When advance_by can't advance the iterator by the number of requested elements it now returns the amount by which it couldn't be advanced instead of the amount by which it did.
This simplifies adapters like chain, flatten or cycle because the remainder doesn't have to be calculated as the difference between requested steps and completed steps anymore.
Additionally switching from `Result<(), usize>` to `Result<(), NonZeroUsize>` reduces the size of the result and makes converting from/to a usize representing the number of remaining steps cheap.
Add `#[inline]` to CStr trait implementations
Fixes#109674
I noticed other usages of traits on `CStr` weren't being inlined, so also added hints to the other implementations
A successful advance is now signalled by returning `0` and other values now represent the remaining number
of steps that couldn't be advanced as opposed to the amount of steps that have been advanced during a partial advance_by.
This simplifies adapters a bit, replacing some `match`/`if` with arithmetic. Whether this is beneficial overall depends
on whether `advance_by` is mostly used as a building-block for other iterator methods and adapters or whether
we also see uses by users where `Result` might be more useful.
Stabilize `nonnull_slice_from_raw_parts`
FCP is done: https://github.com/rust-lang/rust/issues/71941#issuecomment-1100910416
Note that this doesn't const-stabilize `NonNull::slice_from_raw_parts` as `slice_from_raw_parts_mut` isn't const-stabilized yet. Given #67456 and #57349, it's not likely available soon, meanwhile, stabilizing only the feature makes some sense, I think.
Closes#71941
Add #[inline] to as_deref
While working on https://github.com/rust-lang/rust/pull/109247 I found an `as_deref` call in the compiler that should have been inlined. This fixes the missing inlining (but doesn't address the perf issues I was chasing).
r? `@thomcc`
Clarify that copied allocators must behave the same
Currently, the safety documentation for `Allocator` says that a cloned or moved allocator must behave the same as the original. However, it does not specify that a copied allocator must behave the same, and it's possible to construct an allocator that permits being moved or cloned, but sometimes produces a new allocator when copied.
<details>
<summary>Contrived example which results in a Miri error</summary>
```rust
#![feature(allocator_api, once_cell, strict_provenance)]
use std::{
alloc::{AllocError, Allocator, Global, Layout},
collections::HashMap,
hint,
marker::PhantomPinned,
num::NonZeroUsize,
pin::Pin,
ptr::{addr_of, NonNull},
sync::{LazyLock, Mutex},
};
mod source_allocator {
use super::*;
// `SourceAllocator` has 3 states:
// - invalid value: is_cloned == false, source != self.addr()
// - source value: is_cloned == false, source == self.addr()
// - cloned value: is_cloned == true
pub struct SourceAllocator {
is_cloned: bool,
source: usize,
_pin: PhantomPinned,
}
impl SourceAllocator {
// Returns a pinned source value (pointing to itself).
pub fn new_source() -> Pin<Box<Self>> {
let mut b = Box::new(Self {
is_cloned: false,
source: 0,
_pin: PhantomPinned,
});
b.source = b.addr();
Box::into_pin(b)
}
fn addr(&self) -> usize {
addr_of!(*self).addr()
}
// Invalid values point to source 0.
// Source values point to themselves.
// Cloned values point to their corresponding source.
fn source(&self) -> usize {
if self.is_cloned || self.addr() == self.source {
self.source
} else {
0
}
}
}
// Copying an invalid value produces an invalid value.
// Copying a source value produces an invalid value.
// Copying a cloned value produces a cloned value with the same source.
impl Copy for SourceAllocator {}
// Cloning an invalid value produces an invalid value.
// Cloning a source value produces a cloned value with that source.
// Cloning a cloned value produces a cloned value with the same source.
impl Clone for SourceAllocator {
fn clone(&self) -> Self {
if self.is_cloned || self.addr() != self.source {
*self
} else {
Self {
is_cloned: true,
source: self.source,
_pin: PhantomPinned,
}
}
}
}
static SOURCE_MAP: LazyLock<Mutex<HashMap<NonZeroUsize, usize>>> =
LazyLock::new(Default::default);
// SAFETY: Wraps `Global`'s methods with additional tracking.
// All invalid values share blocks with each other.
// Each source value shares blocks with all cloned values pointing to it.
// Cloning an allocator always produces a compatible allocator:
// - Cloning an invalid value produces another invalid value.
// - Cloning a source value produces a cloned value pointing to it.
// - Cloning a cloned value produces another cloned value with the same source.
// Moving an allocator always produces a compatible allocator:
// - Invalid values remain invalid when moved.
// - Source values cannot be moved, since they are always pinned to the heap.
// - Cloned values keep the same source when moved.
unsafe impl Allocator for SourceAllocator {
fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
let mut map = SOURCE_MAP.lock().unwrap();
let block = Global.allocate(layout)?;
let block_addr = block.cast::<u8>().addr();
map.insert(block_addr, self.source());
Ok(block)
}
unsafe fn deallocate(&self, block: NonNull<u8>, layout: Layout) {
let mut map = SOURCE_MAP.lock().unwrap();
let block_addr = block.addr();
// SAFETY: `block` came from an allocator that shares blocks with this allocator.
if map.remove(&block_addr) != Some(self.source()) {
hint::unreachable_unchecked()
}
Global.deallocate(block, layout)
}
}
}
use source_allocator::SourceAllocator;
// SAFETY: `alloc1` and `alloc2` must share blocks.
unsafe fn test_same(alloc1: &SourceAllocator, alloc2: &SourceAllocator) {
let ptr = alloc1.allocate(Layout:🆕:<i32>()).unwrap();
alloc2.deallocate(ptr.cast(), Layout:🆕:<i32>());
}
fn main() {
let orig = &*SourceAllocator::new_source();
let orig_cloned1 = &orig.clone();
let orig_cloned2 = &orig.clone();
let copied = &{ *orig };
let copied_cloned1 = &copied.clone();
let copied_cloned2 = &copied.clone();
unsafe {
test_same(orig, orig_cloned1);
test_same(orig_cloned1, orig_cloned2);
test_same(copied, copied_cloned1);
test_same(copied_cloned1, copied_cloned2);
test_same(orig, copied); // error
}
}
```
</details>
This could result in issues in the future for algorithms that specialize on `Copy` types. Right now, nothing in the standard library that depends on `Allocator + Clone` is susceptible to this issue, but I still think it would make sense to specify that copying an allocator is always as valid as cloning it.
Currently, to know what the function will return when the pattern
doesn't match, the docs require the reader to understand the
implementation detail and mentally evaluate or run the example
code. It is not immediately clear.
This PR makes it more explicit so the reader can quickly find the
information.
Implement Default for some alloc/core iterators
Add `Default` impls to the following collection iterators:
* slice::{Iter, IterMut}
* binary_heap::IntoIter
* btree::map::{Iter, IterMut, Keys, Values, Range, IntoIter, IntoKeys, IntoValues}
* btree::set::{Iter, IntoIter, Range}
* linked_list::IntoIter
* vec::IntoIter
and these adapters:
* adapters::{Chain, Cloned, Copied, Rev, Enumerate, Flatten, Fuse, Rev}
For iterators which are generic over allocators it only implements it for the global allocator because we can't conjure an allocator from nothing or would have to turn the allocator field into an `Option` just for this change.
These changes will be insta-stable.
ACP: https://github.com/rust-lang/libs-team/issues/77
Add #[inline] to the Into for From impl
I was skimming through the standard library MIR and I noticed a handful of very suspicious `Into::into` calls in `alloc`. ~Since this is a trivial wrapper function, `#[inline(always)]` seems appropriate.;~ `#[inline]` works too and is a lot less spooky.
r? `@thomcc`
Shrink unicode case-mapping LUTs by 24k
I was looking into the binary bloat of a small program using `str::to_lowercase` and `str::to_uppercase`, and noticed that the lookup tables used for case mapping had a lot of zero-bytes in them. The reason for this is that since some characters map to up to three other characters when lower or uppercased, the LUTs store a `[char; 3]` for each character. However, the vast majority of cases only map to a single new character, in other words most of the entries are e.g. `(lowerc, [upperc, '\0', '\0'])`.
This PR introduces a new encoding scheme for these tables.
The changes reduces the size of my test binary by about 24K.
I've also done some `#[bench]`marks on unicode-heavy test data, and found that the performance of both `str::to_lowercase` and `str::to_uppercase` improves by up to 20%. These measurements are obviously very dependent on the character distribution of the data.
Someone else will have to decide whether this more complex scheme is worth it or not, I was just goofing around a bit and here's what came out of it 🤷♂️ No hard feelings if this isn't wanted!
fix typo in the creation of OpenOption for RustyHermit
Due to this typo we have to build a workaround for issue hermitcore/libhermit-rs#191.
RustyHermit is a tier 3 platform and backward compatibility does not have to be guaranteed.
Add block-based mutex unlocking example
This modifies the existing example in the Mutex docs to show both `drop()` and block based early unlocking.
Alternative to #81872, which is getting closed.
panic_immediate_abort requires abort as a panic strategy
Guide `panic_immediate_abort` users away from `-Cpanic=unwind` and towards `-Cpanic=abort` to avoid an accidental use of the feature with the unwind strategy, e.g., on a targets where unwind is the default.
The `-Cpanic=unwind` combination doesn't offer the same benefits, since the code would still be generated under the assumption that functions implemented in Rust can unwind.
Clarify `Error::last_os_error` can be weird
Fundamentally, querying the OS for error codes is a process that is deeply subject to the whims of chance and fortune. We can account for OS, but not for every combination of platform APIs. A compiled binary may not recognize new errors introduced years later. We should clarify a few especially odd situations, and what they mean: We can effectively promise nothing... if you ask for Rust to decode errors where none have occurred.
This allows removing mention of ErrorKind::Uncategorized.
That error variant is hidden deliberately, so we should not explicitly mention it.
This fixes#106937.
Since you had an opinion also: Does this solution seem acceptable?
r? ``@ChrisDenton``
Rollup of 7 pull requests
Successful merges:
- #108541 (Suppress `opaque_hidden_inferred_bound` for nested RPITs)
- #109137 (resolve: Querify most cstore access methods (subset 2))
- #109380 (add `known-bug` test for unsoundness issue)
- #109462 (Make alias-eq have a relation direction (and rename it to alias-relate))
- #109475 (Simpler checked shifts in MIR building)
- #109504 (Stabilize `arc_into_inner` and `rc_into_inner`.)
- #109506 (make param bound vars visibly bound vars with -Zverbose)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Stabilize `arc_into_inner` and `rc_into_inner`.
Stabilize the `arc_into_inner` and `rc_into_inner` library features and thus close#106894.
The changes in this PR also resolve the FIXMEs for adjusting the documentation upon stabilization, and I’ve additionally included some very minor documentation improvements.
```@rustbot``` label +T-libs-api -T-libs
Updates `interpret`, `codegen_ssa`, and `codegen_cranelift` to consume the new cast instead of the intrinsic.
Includes `CastTransmute` for custom MIR building, to be able to test the extra UB.
Custom MIR: Allow optional RET type annotation
This currently doesn't compile because the type of `RET` is inferred, which fails if RET is a composite type and fields are initialised separately.
```rust
#![feature(custom_mir, core_intrinsics)]
extern crate core;
use core::intrinsics::mir::*;
#[custom_mir(dialect = "runtime", phase = "optimized")]
fn fn0() -> (i32, bool) {
mir! ({
RET.0 = 0;
RET.1 = true;
Return()
})
}
```
```
error[E0282]: type annotations needed
--> src/lib.rs:8:9
|
8 | RET.0 = 0;
| ^^^ cannot infer type
For more information about this error, try `rustc --explain E0282`.
```
This PR allows the user to manually specify the return type with `type RET = ...;` if required:
```rust
#[custom_mir(dialect = "runtime", phase = "optimized")]
fn fn0() -> (i32, bool) {
mir! (
type RET = (i32, bool);
{
RET.0 = 0;
RET.1 = true;
Return()
}
)
}
```
The syntax is not optimal, I'm happy to see other suggestions. Ideally I wanted it to be a normal type annotation like `let RET: ...;`, but this runs into the multiple parsing options error during macro expansion, as it can be parsed as a normal `let` declaration as well.
r? ```@oli-obk``` or ```@tmiasko``` or ```@JakobDegen```
move Option::as_slice to intrinsic
````@scottmcm```` suggested on #109095 I use a direct approach of unpacking the operation in MIR lowering, so here's the implementation.
cc ````@nikic```` as this should hopefully unblock #107224 (though perhaps other changes to the prior implementation, which I left for bootstrapping, are needed).
Drop all messages in bounded channel when destroying the last receiver
Fixes#107466 by splitting the `disconnect` function for receivers/transmitters and dropping all messages in `disconnect_receivers` like the unbounded channel does. Since all receivers must be dropped before the channel is, the messages will already be discarded at that point, so the `Drop` implementation for the channel can be removed.
``@rustbot`` label +T-libs +A-concurrency
Windows: make `Command` prefer non-verbatim paths
When spawning Commands, the path we use can end up being queried using `env::current_exe` (or the equivalent in other languages). Not all applications handle these paths properly therefore we should have a stronger preference for non-verbatim paths when spawning processes.
Implement read_buf for a few more types
Implement read_buf for TcpStream, Stdin, StdinLock, ChildStdout,
ChildStderr (and internally for AnonPipe, Handle, Socket), so
that it skips buffer initialization.
The other provided methods like read_to_string and read_to_end are
implemented in terms of read_buf and so benefit from the optimization
as well.
This commit also implements read_vectored and is_read_vectored where
applicable.
Document `Iterator::sum/product` for Option/Result
Closes#105266
We already document the similar behavior for `collect()` so I believe it makes sense to add this too. The Option/Result implementations *are* documented on their respective pages and the page for `Sum`, but buried amongst many other trait impls which doesn't make it very discoverable.
`````@rustbot````` label +A-docs
Remove the assume(!is_null) from Vec::as_ptr
At a guess, this code is leftover from LLVM was worse at keeping track of the niche information here. In any case, we don't need this anymore: Removing this `assume` doesn't get rid of the `nonnull` attribute on the return type.
Add inlining annotations in `dec2flt`.
Currently, the combination of `dec2flt` being generic and the `FromStr` implementaions
containing inline anttributes causes massive amounts of assembly to be generated whenever
these implementation are used. In addition, the assembly has calls to function which ought to
be inlined, but they are not (even when using lto).
This Pr fixes this.
Distribute libntdll.a with windows-gnu toolchains
This allows the OS loader to load essential functions (e.g. read/write file) at load time instead of lazily doing so at runtime.
r? libs
Improve `Iterator::collect_into` documentation
This improves the examples in the documentation of `Iterator::collect_into`, replacing the usages of `println!` with `assert_eq!` as suggested on [IRLO](https://internals.rust-lang.org/t/18534/9).
Due to this typo we have to build a workaround for issue
hermitcore/libhermit-rs#191.
RustyHermit is a tier 3 platform and backward compatibility does
not have to be guaranteed.
read_buf_exact: on error, all read bytes are appended to the buffer
Guarantee that when `read_buf_exact` returns, all bytes read will be
appended to the buffer. Including the case when the operations fails.
The motivating use case are operations on a non-blocking reader. When
`read_buf_exact` fails with `ErrorKind::WouldBlock` error, the operation
can be resumed at a later time.
Beautify pin! docs
This makes pin docs a little bit less jargon-y and easier to read, by
* splitting up the sentences
* making them less interrupted by punctuation
* turning the footnotes into paragraphs, as they contain useful information that shouldn't be hidden in footnotes. Footnotes also interrupt the read flow.
Use `size_of_val` instead of manual calculation
Very minor thing that I happened to notice in passing, but it's both shorter and [means it gets `mul nsw`](https://rust.godbolt.org/z/Y9KxYETv5), so why not.
The interaction between the environment variable methods can be confusing. Specifically `env_clear` and `remove_env` have a side effects not mentioned: they disable inheriting environment variables from the parent process. I wanted to fully document this behavior as well as explain relevant edge cases in each of the `Command` env methods.
This is further confused by the return of `get_envs` which will return key/None if `remove_env` has been used, but an empty iterator if `env_clear` has been called. Or a non-empty iterator if `env_clear` was called and later explicit mappings are added. Currently there is no way (that I'm able to find) of observing whether or not the internal `env_clear=true` been toggled on the `Command` struct via its public API.
Ultimately environment variable mappings can be in one of several states:
- Explicitly set value (via `envs` / `env`) will take precedence over parent mapping
- Not explicitly set, will inherit mapping from parent
- Explicitly removed via `remove_env`, this single mapping will not inherit from parent
- Implicitly removed via `env_clear`, no mappings will inherit from parent
I tried to represent this in the relevant sections of the docs.
This is my second ever doc PR (whoop!). I'm happy to take specific or general doc feedback. Also happy to explain the logic behind any changes or additions I made.
The indices are encoded as `u32`s in the range of invalid `char`s, so
that we know that if any mapping fails to parse as a `char` we should
use the value for lookup in the multi-table.
This avoids the second binary search in cases where a multi-`char`
mapping is needed.
Idea from @nikic
This makes pin docs a little bit less jargon-y and easier to read, by
* splitting up the sentences
* making them less interrupted by punctuation
* turning the footnotes into paragraphs, as they contain useful information
that shouldn't be hidden in footnotes. Footnotes also interrupt the read flow.
* other improvements and simplifications
For larger applications it's important that users set `RUST_MIN_STACK`
at the start of their program because `min_stack` caches the value.
Not doing so can lead to their `env::set_var` call surprisingly not having any effect.
Flatten/inline format_args!() and (string and int) literal arguments into format_args!()
Implements https://github.com/rust-lang/rust/issues/78356
Gated behind `-Zflatten-format-args=yes`.
Part of #99012
This change inlines string literals, integer literals and nested format_args!() into format_args!() during ast lowering, making all of the following pairs result in equivalent hir:
```rust
println!("Hello, {}!", "World");
println!("Hello, World!");
```
```rust
println!("[info] {}", format_args!("error"));
println!("[info] error");
```
```rust
println!("[{}] {}", status, format_args!("error: {}", msg));
println!("[{}] error: {}", status, msg);
```
```rust
println!("{} + {} = {}", 1, 2, 1 + 2);
println!("1 + 2 = {}", 1 + 2);
```
And so on.
This is useful for macros. E.g. a `log::info!()` macro could just pass the tokens from the user directly into a `format_args!()` that gets efficiently flattened/inlined into a `format_args!("info: {}")`.
It also means that `dbg!(x)` will have its file, line, and expression name inlined:
```rust
eprintln!("[{}:{}] {} = {:#?}", file!(), line!(), stringify!(x), x); // before
eprintln!("[example.rs:1] x = {:#?}", x); // after
```
Which can be nice in some cases, but also means a lot more unique static strings than before if dbg!() is used a lot.
The majority of char case replacements are single char replacements,
so storing them as [char; 3] wastes a lot of space.
This commit splits the replacement tables for both `to_lower` and
`to_upper` into two separate tables, one with single-character mappings
and one with multi-character mappings.
This reduces the binary size for programs using all of these tables
with roughly 24K bytes.
Since ascii chars are already handled by a special case in the
`to_lower` and `to_upper` functions, there's no need to waste space on
them in the LUTs.
Ensure `ptr::read` gets all the same LLVM `load` metadata that dereferencing does
I was looking into `array::IntoIter` optimization, and noticed that it wasn't annotating the loads with `noundef` for simple things like `array::IntoIter<i32, N>`. Trying to narrow it down, it seems that was because `MaybeUninit::assume_init_read` isn't marking the load as initialized (<https://rust.godbolt.org/z/Mxd8TPTnv>), which is unfortunate since that's basically its reason to exist.
The root cause is that `ptr::read` is currently implemented via the *untyped* `copy_nonoverlapping`, and thus the `load` doesn't get any type-aware metadata: no `noundef`, no `!range`. This PR solves that by lowering `ptr::read(p)` to `copy *p` in MIR, for which the backends already do the right thing.
Fortuitiously, this also improves the IR we give to LLVM for things like `mem::replace`, and fixes a couple of long-standing bugs where `ptr::read` on `Copy` types was worse than `*`ing them.
Zulip conversation: <https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/Move.20array.3A.3AIntoIter.20to.20ManuallyDrop/near/341189936>
cc `@erikdesjardins` `@JakobDegen` `@workingjubilee` `@the8472`
Fixes#106369Fixes#73258
`/dev/urandom` is usually available on Emscripten, except when using
the special `NODERAWFS` filesystem backend, which replaces all normal
filesystem access with direct Node.js operations.
Since this filesystem backend directly access the filesystem on the
OS, it is not recommended to depend on `/dev/urandom`, especially
when trying to run the Wasm binary on OSes that are not Unix-based.
This can be considered a non-functional change, since Emscripten
implements `/dev/urandom` in the same way as `getentropy()` when not
linking with `-sNODERAWFS`.
Remove `identity_future` indirection
This was previously needed because the indirection used to hide some unexplained lifetime errors, which it turned out were related to the `min_choice` algorithm.
Removing the indirection also solves a couple of cycle errors, large moves and makes async blocks support the `#[track_caller]`annotation.
Fixes https://github.com/rust-lang/rust/issues/104826.
use `as_ptr` to determine the address of atomics
The PR #107736 renamed atomic `as_mut_ptr` to `as_ptr`. Consequently, the futex implementation of the tier-3 platform `RutyHermit` has to use this new interface. In addition, this PR removes also an unused import.
Stabilize `atomic_as_ptr`
Fixes#66893
This stabilizes the `as_ptr` methods for atomics. The stabilization feature gate used here is `atomic_as_ptr` which supersedes `atomic_mut_ptr` to match the change in https://github.com/rust-lang/rust/pull/107736.
This needs FCP.
New stable API:
```rust
impl AtomicBool {
pub const fn as_ptr(&self) -> *mut bool;
}
impl AtomicI32 {
pub const fn as_ptr(&self) -> *mut i32;
}
// Includes all other atomic types
impl<T> AtomicPtr<T> {
pub const fn as_ptr(&self) -> *mut *mut T;
}
```
r? libs-api
``@rustbot`` label +needs-fcp
Move `Option::as_slice` to an always-sound implementation
This approach depends on CSE to not have any branches or selects when the guessed offset is correct -- which it always will be right now -- but to also be *sound* (just less efficient) if the layout algorithms change such that the guess is incorrect.
The codegen test confirms that CSE handles this as expected, leaving the optimal codegen.
cc JakobDegen #108545
Introduce `Rc::into_inner`, as a parallel to `Arc::into_inner`
Unlike `Arc`, `Rc` doesn't have the same race condition to avoid, but
maintaining an equivalent API still makes it easier to work with both
`Rc` and `Arc`.
This approach depends on CSE to not have any branches or selects when the guessed offset is correct -- which it always will be right now -- but to also be *sound* (just less efficient) if the layout algorithms change such that the guess is incorrect.
I was looking into `array::IntoIter` optimization, and noticed that it wasn't annotating the loads with `noundef` for simple things like `array::IntoIter<i32, N>`.
Turned out to be a more general problem as `MaybeUninit::assume_init_read` isn't marking the load as initialized (<https://rust.godbolt.org/z/Mxd8TPTnv>), which is unfortunate since that's basically its reason to exist.
This PR lowers `ptr::read(p)` to `copy *p` in MIR, which fortuitiously also improves the IR we give to LLVM for things like `mem::replace`.
Unlike `Arc`, `Rc` doesn't have the same race condition to avoid, but
maintaining an equivalent API still makes it easier to work with both
`Rc` and `Arc`.
Rollup of 9 pull requests
Successful merges:
- #104363 (Make `unused_allocation` lint against `Box::new` too)
- #106633 (Stabilize `nonzero_min_max`)
- #106844 (allow negative numeric literals in `concat!`)
- #108071 (Implement goal caching with the new solver)
- #108542 (Force parentheses around `match` expression in binary expression)
- #108690 (Place size limits on query keys and values)
- #108708 (Prevent overflow through Arc::downgrade)
- #108739 (Prevent the `start_bx` basic block in codegen from having two `Builder`s at the same time)
- #108806 (Querify register_tools and post-expansion early lints)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Guarantee that when `read_buf_exact` returns, all bytes read will be
appended to the buffer. Including the case when the operations fails.
The motivating use case are operations on a non-blocking reader. When
`read_buf_exact` fails with `ErrorKind::WouldBlock` error, the operation
can be resumed at a later time.
Stabilize `nonzero_min_max`
## Overall
Stabilizes `nonzero_min_max` to allow the "infallible" construction of ordinary minimum and maximum `NonZero*` instances.
The feature is fairly straightforward and already matured for some time in stable toolchains.
```rust
let _ = NonZeroU8::MIN;
let _ = NonZeroI32::MAX;
```
## History
* On 2022-01-25, implementation was [created](https://github.com/rust-lang/rust/pull/93293).
## Considerations
* This report is fruit of the inanition observed after two unsuccessful attempts at getting feedback.
* Other constant variants discussed at https://github.com/rust-lang/rust/issues/89065#issuecomment-923238190 are orthogonal to this feature.
Fixes https://github.com/rust-lang/rust/issues/89065
Make `unused_allocation` lint against `Box::new` too
Previously it only linted against `box` syntax, which likely won't ever be stabilized, which is pretty useless. Even now I'm not sure if it's a meaningful lint, but it's at least something 🤷
This means that code like the following will be linted against:
```rust
Box::new([1, 2, 3]).len();
f(&Box::new(1)); // where f : &i32 -> ()
```
The lint works by checking if a `Box::new` (or `box`) expression has an a borrow adjustment, meaning that the code that first stores the box in a variable won't be linted against:
```rust
let boxed = Box::new([1, 2, 3]); // no lint
boxed.len();
```
Move __thread_local_inner to sys
Move `__thread_local_inner` macro in `crate:🧵:local` to `crate::sys`. Initially, I was thinking about removing this macro completely, but I could not find a way to create the generic statics without macros, so in the end, I just moved to code around.
This probably will need a rebase once https://github.com/rust-lang/rust/pull/108917 is merged
r? ``@workingjubilee``
Fix `vec_deque::Drain` FIXME
In my original `VecDeque` rewrite, I didn't use `VecDeque::slice_ranges` in `Drain::as_slices`, even though that's basically the exact use case for `slice_ranges`. The reason for this was that a `VecDeque` wrapped in a `Drain` actually has its length set to `drain_start`, so that there's no potential use after free if you `mem::forget` the `Drain`. I modified `slice_ranges` to accept an explicit `len` parameter instead, which it now uses to bounds check the given range. This way, `Drain::as_slices` can use `slice_ranges` internally instead of having to basically just copy paste the `slice_ranges` code. Since `slice_ranges` is just an internal helper function, this shouldn't change the user facing behavior in any way.
This allows removing all the platform-dependent code from `library/std/src/thread/local.rs` and `library/std/src/thread/mod.rs`
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
Split the __thread_local_inner macro to make it more readable. Also move
everything to crate::sys::common::thread_local.
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
Move __thread_local_inner macro in crate:🧵:local to crate::sys.
Currently, the tidy check does not fail for `library/std/src/thread/local.rs` even though it contains platform specific code. This is beacause target_family did not exist at the time the tidy checks were written [1].
[1]: https://github.com/rust-lang/rust/pull/105861#discussion_r1125841678
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
Fix the docs for pointer method with_metadata_of
The name of the argument to `{*const T, *mut T}::with_metadata_of` was changed from `val` to `meta` recently, but the docs weren't updated to match.
Relevant pull request: #103701
Rollup of 8 pull requests
Successful merges:
- #108754 (Retry `pred_known_to_hold_modulo_regions` with fulfillment if ambiguous)
- #108759 (1.41.1 supported 32-bit Apple targets)
- #108839 (Canonicalize root var when making response from new solver)
- #108856 (Remove DropAndReplace terminator)
- #108882 (Tweak E0740)
- #108898 (Set `LIBC_CHECK_CFG=1` when building Rust code in bootstrap)
- #108911 (Improve rustdoc-gui/tester.js code a bit)
- #108916 (Remove an unused return value in `rustc_hir_typeck`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Guide `panic_immediate_abort` users away from `-Cpanic=unwind` and
towards `-Cpanic=abort` to avoid an accidental use of the feature with
the unwind strategy, e.g., on a targets where unwind is the default.
The `-Cpanic=unwind` combination doesn't offer the same benefits, since
the code would still be generated under the assumption that functions
implemented in Rust can unwind.
This was previously needed because the indirection used to hide some unexplained lifetime errors, which it turned out were related to the `min_choice` algorithm.
Removing the indirection also solves a couple of cycle errors, large moves and makes async blocks support the `#[track_caller]` annotation.
Use `nuw` when calculating slice lengths from `Range`s
An `assume` would definitely not be worth it, but since the flag is almost free we might as well tell LLVM this, especially on `_unchecked` calls where there's no obvious way for it to deduce it.
(Today neither safe nor unsafe indexing gets it: <https://rust.godbolt.org/z/G1jYT548s>)
Add `round_ties_even` to `f32` and `f64`
Tracking issue: #96710
Redux of #82273. See also #55107
Adds a new method, `round_ties_even`, to `f32` and `f64`, that rounds the float to the nearest integer , rounding halfway cases to the number with an even least significant bit. Uses the `roundeven` LLVM intrinsic to do this.
Of the five IEEE 754 rounding modes, this is the only one that doesn't already have a round-to-integer function exposed by Rust (others are `round`, `floor`, `ceil`, and `trunc`). Ties-to-even is also the rounding mode used for int-to-float and float-to-float `as` casts, as well as float arithmentic operations. So not having an explicit rounding method for it seems like an oversight.
Bikeshed: this PR currently uses `round_ties_even` for the name of the method. But maybe `round_ties_to_even` is better, or `round_even`, or `round_to_even`?
Implement read_buf for TcpStream, Stdin, StdinLock, ChildStdout,
ChildStderr (and internally for AnonPipe, Handle, Socket), so
that it skips buffer initialization.
The other provided methods like read_to_string and read_to_end are
implemented in terms of read_buf and so benefit from the optimization
as well.
This commit also implements read_vectored and is_read_vectored where
applicable.
An `assume` would definitely not be worth it, but since the flag is almost free we might as well tell LLVM this, especially on `_unchecked` calls where there's no obvious way for it to deduce it.
(Today neither safe nor unsafe indexing gets it: <https://rust.godbolt.org/z/G1jYT548s>)
Use `partial_cmp` to implement tuple `lt`/`le`/`ge`/`gt`
In today's implementation, `(A, B)::gt` contains calls to *both* `A::eq` *and* `A::gt`.
That's fine for primitives, but for things like `String`s it's kinda weird -- `(String, usize)::gt` has a call to both `bcmp` and `memcmp` (<https://rust.godbolt.org/z/7jbbPMesf>) because when `bcmp` says the `String`s aren't equal, it turns around and calls `memcmp` to find out which one's bigger.
This PR changes the implementation to instead implement `(A, …, C, Z)::gt` using `A::partial_cmp`, `…::partial_cmp`, `C::partial_cmp`, and `Z::gt`. (And analogously for `lt`, `le`, and `ge`.) That way expensive comparisons don't need to be repeated.
Technically this is an observable change on stable, so I've marked it `needs-fcp` + `T-libs-api` and will
r? rust-lang/libs-api
I'm hoping that this will be non-controversial, however, since it's very similar to the observable changes that were made to the derives (#81384#98655) -- like those, this only changes behaviour if a type overrode behaviour in a way inconsistent with the rules for the various traits involved.
(The first commit here is #108156, adding the codegen test, which I used to make sure this doesn't regress behaviour for primitives.)
Zulip conversation about this change: <https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/.60.3E.60.20on.20Tuples/near/328392927>.
Add vectored positioned I/O on Unix
Add methods for vectored I/O with an offset on `File` for `unix` under `#![feature(unix_file_vectored_at)]`.
The new methods are wrappers around `preadv` and `pwritev`.
Tracking issue: #89517
Match unmatched backticks in library/
Found with GNU grep:
```
grep -rEn '^(([^`]*`){2})*[^`]*`[^`]*$' library/ | rg -v '\s*[//]?.{1,2}```'
```
split out from #108685 as per advice.
Add `Atomic*::from_ptr`
This PR adds functions in the following form to all atomic types:
```rust
impl AtomicT {
pub const unsafe fn from_ptr<'a>(ptr: *mut T) -> &'a AtomicT;
}
```
r? `@m-ou-se` (we've talked about it before)
I'm not sure about docs & safety requirements, I'd appreciate some feedback on them.
Add support for QNX Neutrino to standard library
This change:
- adds standard library support for QNX Neutrino (7.1).
- upgrades `libc` to version `0.2.139` which supports QNX Neutrino
`@gh-tr`
⚠️ Backtraces on QNX require https://github.com/rust-lang/backtrace-rs/pull/507 which is not yet merged! (But everything else works without these changes) ⚠️
Tested mainly with a x86_64 virtual machine (see qnx-nto.md) and partially with an aarch64 hardware (some tests fail due to constrained resources).
Merge two different equality specialization traits in `core`
Arrays and slices each had their own version of this, without a matching set of `impl`s.
Merge them into one (still-`pub(crate)`) `cmp::BytewiseEq` trait, so we can stop doing all these things twice.
And that means that the `[T]::eq` → `memcmp` specialization picks up a bunch of types where that previously only worked for arrays, so examples like <https://rust.godbolt.org/z/KjsG8MGGT> will use it now instead of emitting loops.
r? the8472
Add `Option::as_`(`mut_`)`slice`
This adds the following functions:
* `Option<T>::as_slice(&self) -> &[T]`
* `Option<T>::as_mut_slice(&mut self) -> &[T]`
The `as_slice` and `as_mut_slice_mut` functions benefit from an optimization that makes them completely branch-free. ~~Unfortunately, this optimization is not available on by-value Options, therefore the `into_slice` implementations use the plain `match` + `slice::from_ref` approach.~~
Note that the optimization's soundness hinges on the fact that either the niche optimization makes the offset of the `Some(_)` contents zero or the mempory layout of `Option<T>` is equal to that of `Option<MaybeUninit<T>>`.
The idea has been discussed on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/Option.3A.3Aas_slice). Notably the idea for the `as_slice_mut` and `into_slice´ methods came from `@cuviper` and `@Sp00ph` hardened the optimization against niche-optimized Options.
The [rust playground](https://play.rust-lang.org/?version=nightly&mode=release&edition=2021&gist=74f8e4239a19f454c183aaf7b4a969e0) shows that the generated assembly of the optimized method is basically only a copy while the naive method generates code containing a `test dx, dx` on x86_64.
---
EDIT from reviewer: ACP is https://github.com/rust-lang/libs-team/issues/150
Remove or document uses of #[rustc_box] in library
r? `@thomcc`
Only one of these uses is tested for in the rustc-perf benchmark suite. The impact there on compile time is somewhat dramatic, but I am inclined to make this change as a simplification to the library and wait for people to complain if it explodes their compilation time. I think in the absence of data or reports from users about what code paths really matter, if we are optimizing for compilation time, it's hard to argue against using `#[rustc_box]` everywhere we currently call `Box::new`.
add missing feature in core/tests
https://github.com/rust-lang/rust/pull/104265 introduced the `ip_in_core` feature. For some reason core tests seem to still build without that feature -- no idea how that is possible. Might be related to https://github.com/rust-lang/rust/issues/15702? I was under the impression that `pub use` with different stability doesn't actually work. That's why `intrinsics::transmute` is stable, for example.
Either way, core tests fail to build in miri-test-libstd, and adding the feature fixes that.
r? ```@thomcc```
This adds the following functions:
* `Option<T>::as_slice(&self) -> &[T]`
* `Option<T>::as_slice_mut(&mut self) -> &[T]`
The `as_slice` and `as_slice_mut` functions benefit from an
optimization that makes them completely branch-free.
Note that the optimization's soundness hinges on the fact that either
the niche optimization makes the offset of the `Some(_)` contents zero
or the mempory layout of `Option<T>` is equal to that of
`Option<MaybeUninit<T>>`.
Inline `Poll` methods
With `opt-level="z"`, the `Poll::map*` methods are sometimes not inlined (see <https://godbolt.org/z/ca5ajKTEK>). This PR adds `#[inline]` to these methods. I have a project that can benefit from this change, but do we want to enable this behavior universally?
Fixes#101080.
Stabilize `#![feature(target_feature_11)]`
## Stabilization report
### Summary
Allows for safe functions to be marked with `#[target_feature]` attributes.
Functions marked with `#[target_feature]` are generally considered as unsafe functions: they are unsafe to call, cannot be assigned to safe function pointers, and don't implement the `Fn*` traits.
However, calling them from other `#[target_feature]` functions with a superset of features is safe.
```rust
// Demonstration function
#[target_feature(enable = "avx2")]
fn avx2() {}
fn foo() {
// Calling `avx2` here is unsafe, as we must ensure
// that AVX is available first.
unsafe {
avx2();
}
}
#[target_feature(enable = "avx2")]
fn bar() {
// Calling `avx2` here is safe.
avx2();
}
```
### Test cases
Tests for this feature can be found in [`src/test/ui/rfcs/rfc-2396-target_feature-11/`](b67ba9ba20/src/test/ui/rfcs/rfc-2396-target_feature-11/).
### Edge cases
- https://github.com/rust-lang/rust/issues/73631
Closures defined inside functions marked with `#[target_feature]` inherit the target features of their parent function. They can still be assigned to safe function pointers and implement the appropriate `Fn*` traits.
```rust
#[target_feature(enable = "avx2")]
fn qux() {
let my_closure = || avx2(); // this call to `avx2` is safe
let f: fn() = my_closure;
}
```
This means that in order to call a function with `#[target_feature]`, you must show that the target-feature is available while the function executes *and* for as long as whatever may escape from that function lives.
### Documentation
- Reference: https://github.com/rust-lang/reference/pull/1181
---
cc tracking issue #69098
r? `@ghost`
[stdio][windows] Use MBTWC and WCTMB
`MultiByteToWideChar` and `WideCharToMultiByte` are extremely well optimized, and therefore should probably be used when we know we can (specifically in the Windows stdio stuff).
Fixes#107092
Move IpAddr, SocketAddr and V4+V6 related types to `core`
Implements RFC https://github.com/rust-lang/rfcs/pull/2832. The RFC has completed FCP with disposition merge, but is not yet merged.
Moves IP types to `core` as specified in the RFC.
The full list of moved types is: `IpAddr`, `Ipv4Addr`, `Ipv6Addr`, `SocketAddr`, `SocketAddrV4`, `SocketAddrV6`, `Ipv6MulticastScope` and `AddrParseError`.
Doing this move was one of the main driving arguments behind #78802.
