Clean and enable `rustdoc::unescaped_backticks` for `core/alloc/std/test/proc_macro`
I am not sure if the lint is supposed to be "ready enough" (since it is `allow` by default), but it does catch a couple issues in `core` (`alloc`, `std`, `test` and `proc_macro` are already clean), so I propose making it `warn` in all the crates rendered in the website.
Cc: `@GuillaumeGomez`
Update compiler_builtins to 0.1.114
The `weak-intrinsics` feature was removed from compiler_builtins in https://github.com/rust-lang/compiler-builtins/pull/598, so dropped the `compiler-builtins-weak-intrinsics` feature from alloc/std/sysroot.
In https://github.com/rust-lang/compiler-builtins/pull/593, some builtins for f16/f128 were added. These don't work for all compiler backends, so add a `compiler-builtins-no-f16-f128` feature and disable it for cranelift and gcc.
std: unsafe-wrap personality::dwarf::eh
Moves the forbiddance up a little. This is another largely whitespace diff, except for hoisting some variable declarations to allow enclosing the `unsafe {}` scope fully and make it clearer where the bounds of some temporaries are.
Replace `io::Cursor::{remaining_slice, is_empty}`
This is a late follow up to the concerns raised in https://github.com/rust-lang/rust/issues/86369.
https://github.com/rust-lang/rust/issues/86369#issuecomment-953096691
> This API seems focussed on the `Read` side of things. When `Seek`ing around and `Write`ing data, `is_empty` becomes confusing and `remaining_slice` is not very useful. When writing, the part of the slice before the cursor is much more interesting. Maybe we should have functions for both? Or a single function that returns both slices? (If we also have a `mut` version, a single function would be useful to allow mutable access to both sides at once.)
New feature name: `cursor_remaining` > `cursor_split`.
Added functions:
```rust
fn split(&self) -> (&[u8], &[u8]);
// fn before(&self) -> &[u8];
// fn after(&self) -> &[u8];
fn split_mut(&mut self) -> (&mut [u8], &mut [u8]);
// fn before_mut(&mut self) -> &mut [u8];
// fn after_mut(&mut self) -> &mut [u8];
```
A question was raised in https://github.com/rust-lang/rust/issues/86369#issuecomment-927124211 about whether to return a lifetime that would reflect the lifetime of the underlying bytes (`impl Cursor<&'a [u8]> { fn after(&self) -> &'a [u8] }`). The downside of doing this would be that it would not be possible to implement these functions generically over `T: AsRef<[u8]>`.
## Update
Based on the review, before* and after* methods where removed.
The `weak-intrinsics` feature was removed from compiler_builtins in
https://github.com/rust-lang/compiler-builtins/pull/598, so dropped the
`compiler-builtins-weak-intrinsics` feature from alloc/std/sysroot.
In https://github.com/rust-lang/compiler-builtins/pull/593, some
builtins for f16/f128 were added. These don't work for all compiler
backends, so add a `compiler-builtins-no-f16-f128` feature and disable
it for cranelift and gcc. Also disable it for LLVM targets that don't
support it.
Stabilize `const_waker`
Closes: https://github.com/rust-lang/rust/issues/102012.
For `local_waker` and `context_ext` related things, I just ~~moved them to dedicated feature gates and reused their own tracking issue (maybe it's better to open a new one later, but at least they should not be tracked under https://github.com/rust-lang/rust/issues/102012 from the beginning IMO.)~~ reused their own feature gates as suggested by ``@tgross35.``
``@rustbot`` label: +T-libs-api
r? libs-api
Fix doc nits
Many tiny changes to stdlib doc comments to make them consistent (for example "Returns foo", rather than "Return foo"), adding missing periods, paragraph breaks, backticks for monospace style, and other minor nits.
Both these platforms have MSG_NOSIGNAL available, and we should set it for
socket writes in the event that the SIGPIPE handler has been reset to SIG_DFL
(i.e. terminate the process).
I've verified via a quick program at
https://github.com/sunshowers/msg-nosignal-test/ that even when the SIGPIPE
handler is reset to SIG_DFL, writes to closed sockets now error out with EPIPE.
(Under ordinary circumstances UDP writes won't cause MSG_NOSIGNAL.)
Use `#[rustfmt::skip]` on some `use` groups to prevent reordering.
`use` declarations will be reformatted in #125443. Very rarely, there is a desire to force a group of `use` declarations together in a way that auto-formatting will break up. E.g. when you want a single comment to apply to a group. #126776 dealt with all of these in the codebase, ensuring that no comments intended for multiple `use` declarations would end up in the wrong place. But some people were unhappy with it.
This commit uses `#[rustfmt::skip]` to create these custom `use` groups in an idiomatic way for a few of the cases changed in #126776. This works because rustfmt treats any `use` item annotated with `#[rustfmt::skip]` as a barrier and won't reorder other `use` items around it.
r? `@cuviper`
Rollup of 6 pull requests
Successful merges:
- #126908 (Use Cow<'static, str> for InlineAsmTemplatePiece::String)
- #127999 (Inject arm32 shims into Windows metadata generation)
- #128137 (CStr: derive PartialEq, Eq; add test for Ord)
- #128185 (Fix a span error when parsing a wrong param of function.)
- #128187 (Fix 1.80.0 version in RELEASES.md)
- #128189 (Turn an unreachable code path into an ICE)
r? `@ghost`
`@rustbot` modify labels: rollup
Inject arm32 shims into Windows metadata generation
I had been keen to eventually move to using windows-sys as a normal Cargo dependency. But for linking, compile times and other reasons that's unlikely to ever happen.
So if we're sticking with generated bindings then injecting any necessary missing type definitions (i.e. for the MS unsupported arm32) is simpler than defining whole functions ourselves just because we need to manually implement those types on a tier 3 platform. This also reduces the places we need to change when making changes to how we use `#[link]`.
r? libs
std: unsafe-wrap personality::gcc
Nothing seems obviously wrong with these implementations except for some unanswered questions. Admittedly, I don't want to burn excessive time on exceptional exception handlers. Thus this is mostly a brute-force syntactic wrapping and some comments where they seemed correct, creating another largely whitespace diff.
try-job: armhf-gnu
Fix connect timeout for non-linux targets, read readiness of socket connection, Read readiness to detect errors. `Fixes #127018`
Fixes#127018
Connect_timeout would call `poll` and check `pollfd.revents` for POLLHUP error, rather that checking readiness. This behavior was meant for Linux as it returns POLLHUP | POLLOUT | POLLERR in case of errors. But on targets that do not return POLLHUP in `pollfd.revents`, this would indicate a false success and result in this issue. To resolve this we will check readiness of socket using `getsockopt():` and return success from connect_timeout when there are no errors.
Changes were tested on Linux and an rtos.
Thank you.
Import `c_void` rather than using the full path
Follow up to #128092. As requested, this imports `c_void` in more places. I also fixed up some imports to use `core` for core types instead of `crate`. While that is not strictly necessary, I think ideally things in `sys/pal` should only depend on itself or core so that the code is less spaghetti. We're far away from that ideal at the moment but I can at least try to slowly move in that direction.
Also this forbids `unsafe_op_in_unsafe_fn` for library/std/src/sys/pal/windows by fixing up the remaining unsafe bits that are just punting their unsafe requirements onto the caller of the `unsafe` function (or definition macro).
<!--
r? workingjubilee
-->
Replace some `mem::forget`'s with `ManuallyDrop`
> but I would like to see a larger effort to replace all uses of `mem::forget`.
_Originally posted by `@saethlin` in https://github.com/rust-lang/rust/issues/127584#issuecomment-2226087767_
So,
r? `@saethlin`
Sorry, I have finished writing all of this before I got your response.
Fix build failure on vxworks #127084
PR to address issue #127084 .
1. Skip `reset_segpipe` for vxworks
2. Return unimplemented error for vxworks from settimes and lchown
3. Temporarily skip dirfd for vxworks
4. Add allow unused unsafe on read_at and write_at functions in unix/fs.rs
5. Using cfg disable ON_BROKEN_PIPE_FLAG_USED and on_broken_pipe_flag_used() for vxworks
6. Remove old crate::syscommon:🧵:min_stack() reference from process_vxworks.rs and update to set stack size of rtpthread
Thank you.
Fix return type of FileAttr methods on AIX target
At some point it seems `SystemTime::new` changed from returning `SystemTime` to `io::Result<SystemTime>`. This seems to have been addressed on other platforms, but was never changed for AIX.
This was caught by running
```
python3 x.py build --host x86_64-unknown-linux-gnu --target powerpc64-ibm-aix
```
Remove wrapper functions from c.rs
I'd like for the windows `c.rs` just to contain the basic platform definitions and not anything higher level unless absolutely necessary. So this removes some wrapper functions that weren't really necessary in any case. The functions are only used in a few places which themselves are relatively thin wrappers. The "interesting" bit is that we had an `AlertableIoFn` that abstracted over `ReadFileEx` and `WriteFileEx`. I've replaced this with a closure.
Also I removed an `#[allow(unsafe_op_in_unsafe_fn)]` while I was moving things around.
At some point it seems `SystemTime::new` changed from returning `SystemTime` to `io::Result<SystemTime>`. This seems to have been addressed on other platforms, but was never changed for AIX.
This was caught by running
```
python3 x.py build --host x86_64-unknown-linux-gnu --target powerpc64-ibm-aix
```
Clean up warnings + `unsafe_op_in_unsafe_fn` when building std for armv6k-nintendo-3ds
See #127747
ping `@AzureMarker` `@Meziu`
I could only find one instance needing an extra `unsafe` that was not also shared with many other `unix` targets (presumably these will get covered in larger sweeping changes, I didn't want to introduce churn that would potentially conflict with those). The one codepath I found is shared with `vita` however, so also pinging `@nikarh` `@pheki` `@zetanumbers` just to make sure they're aware of this change.
Also removed one unused import from `process_unsupported` which should simply fix the warning for any target that uses it.
Deal with invalid UTF-8 from `gai_strerror`
When the system is using a non-UTF-8 locale, the value will indeed not be UTF-8. That sucks for everyone involved, but is no reason for panic. We can "handle" this gracefully by just using from lossy, replacing the invalid UTF-8 with � and keeping the accidentally valid UTF-8. Good luck when debugging, but at least it's not a crash.
We already do this for `strerror_r`.
fixes#127563
When the system is using a non-UTF-8 locale, the value will indeed not
be UTF-8. That sucks for everyone involved, but is no reason for panic.
We can "handle" this gracefully by just using from lossy, replacing the
invalid UTF-8 with the ? and keeping the accidentally valid UTF-8.
Good luck when debugging, but at least it's not a crash.
We already do this for `strerror_r`.
Windows: move BSD socket shims to netc
On Windows we need to alter a few types so that they can be used in the cross-platform socket code. Currently these alterations are spread throughout the `c` module with some more in the `netc` module.
Let's gather all our BSD compatibility shims in the `netc` module so it's all in one place and easier to discover.
kmc-solid: `#![forbid(unsafe_op_in_unsafe_fn)]`
The path logic _should_ handle the forbiddance in the itron sources correctly, despite them being an "out-of-line" module.
unix: document unsafety for std `sig{action,altstack}`
I found many surprising elements here while trying to wrap a measly 5 functions with `unsafe`. I would rather not "just" mindlessly wrap this code with `unsafe { }`, so I decided to document it properly.
On Unix, this code covers the "create and setup signal handler" part of the stack overflow code, and serves as the primary safety boundary for the signal handler. It is rarely audited, very gnarly, and worth extra attention. It calls other unsafe functions defined in this module, but "can we correctly map the right memory, or find the right address ranges?" are separate questions, and get increasingly platform-specific. The question here is the more general "are we doing everything in the correct order, and setting up the handler in the correct way?"
As part of this audit, I noticed that we do some peculiar things that we should probably refrain from. However, I avoided making changes that I deemed might have a different final result in Rust programs. I did, however, reorder some events so that the signal handler is installed _after_ we install the alternate stack. We do not run much code between these events, but it is probably best if the timespan between the handler being available and the new stack being installed is 0 nanoseconds.
Safely enforce thread name requirements
The requirements for the thread name to be both UTF-8 and null terminated are easily enforced by a wrapper type so lets do that. The fact this used to be just a bare `CString` has tripped me up before because it was entirely safe to use a non UTF-8 `CString`.
Add Process support for UEFI
UEFI does not have an actual process. However, it does provide methods to launch and execute another UEFI image. Having process support is important since it is possible to run rust test suit using `Command::output` and is the first step towards being able to run it for UEFI.
Here is an overview of how the support is implemented.
- We create a copy of the SystemTable. This is required since at least OVMF seems to crash if the original system table is modified.
- Stdout and Stderr pipe works by registering a new `simple_text_output` Protocol and pointing the child system table to use those.
- `Stdio::Inherit` just points the console to the current running image console which seems to work with even 3 levels of process.
- `spawn` is left unimplemented since it does not make sense for UEFI architecture. Additionally, since https://github.com/rust-lang/rust/pull/105458 was merged, the `spawn` and `output` implementations are completely independent.
Rollup of 6 pull requests
Successful merges:
- #127295 (CFI: Support provided methods on traits)
- #127814 (`C-cmse-nonsecure-call`: improved error messages)
- #127949 (fix: explain E0120 better cover cases when its raised)
- #127966 (Use structured suggestions for unconstrained generic parameters on impl blocks)
- #127976 (Lazy type aliases: Diagostics: Detect bivariant ty params that are only used recursively)
- #127978 (Avoid ref when using format! for perf)
r? `@ghost`
`@rustbot` modify labels: rollup
Avoid ref when using format! for perf
Clean up a few minor refs in `format!` macro, as it has a performance cost. Apparently the compiler is unable to inline `format!("{}", &variable)`, and does a run-time double-reference instead (format macro already does one level referencing). Inlining format args prevents accidental `&` misuse.
- Update system table crc32
- Fix unsound use of Box
- Free exit data
- Code improvements
- Introduce OwnedTable
- Update r-efi to latest version
- Use extended_varargs_abi_support for
install_multiple_protocol_interfaces and
uninstall_multiple_protocol_interfaces
- Fix comments
- Stub out args implementation
Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>
`use` declarations will be reformatted in #125443. Very rarely, there is
a desire to force a group of `use` declarations together in a way that
auto-formatting will break up. E.g. when you want a single comment to
apply to a group. #126776 dealt with all of these in the codebase,
ensuring that no comments intended for multiple `use` declarations would
end up in the wrong place. But some people were unhappy with it.
This commit uses `#[rustfmt::skip]` to create these custom `use` groups
in an idiomatic way for a few of the cases changed in #126776. This
works because rustfmt treats any `use` item annotated with
`#[rustfmt::skip]` as a barrier and won't reorder other `use` items
around it.
This is technically "not necessary", as we will "just" segfault instead
if we e.g. arrive inside the handler fn with the null altstack. However,
it seems incorrect to go about this hoping that segfaulting is okay,
seeing as how our purpose here is to mitigate stack overflow problems.
Make sure NEED_ALTSTACK syncs with PAGE_SIZE when we do.
Co-authored-by: Jonas Böttiger <jonasboettiger@icloud.com>
Use ThreadId instead of TLS-address in `ReentrantLock`
Fixes#123458
`ReentrantLock` currently uses the address of a thread local variable as an ID that's unique across all currently running threads. This can lead to uninituitive behavior as in #123458 if TLS blocks get reused. This PR changes `ReentrantLock` to instead use the `ThreadId` provided by `std` as the unique ID. `ThreadId` guarantees uniqueness across the lifetime of the whole process, so we don't need to worry about reusing IDs of terminated threads. The main appeal of this PR is thus the possibility of changing the `ReentrantLock` API to guarantee that if a thread leaks a lock guard, no other thread may ever acquire that lock again.
This does entail some complications:
- previously, the only way to retrieve the current thread ID would've been using `thread::current().id()` which creates a temporary `Arc` and which isn't available in TLS destructors. As part of this PR, the thread ID instead gets cached in its own thread local, as suggested [here](https://github.com/rust-lang/rust/issues/123458#issuecomment-2038207704).
- `ThreadId` is always 64-bit whereas the current implementation uses a usize-sized ID. Since this ID needs to be updated atomically, we can't simply use a single atomic variable on 32 bit platforms. Instead, we fall back to using a (sound) seqlock on 32-bit platforms, which works because only one thread at a time can write to the ID. This seqlock is technically susceptible to the ABA problem, but the attack vector to create actual unsoundness has to be very specific:
- You would need to be able to lock+unlock the lock exactly 2^31 times (or a multiple thereof) while a thread trying to lock it sleeps
- The sleeping thread would have to suspend after reading one half of the thread id but before reading the other half
- The teared result from combining the halves of the thread ID would have to exactly line up with the sleeping thread's ID
The risk of this occurring seems slim enough to be acceptable to me, but correct me if I'm wrong. This also means that the size of the lock increases by 8 bytes on 32-bit platforms, but this also shouldn't be an issue.
Performance wise, I did some crude testing of the only case where this could lead to real slowdowns, which is the case of locking a `ReentrantLock` that's already locked by the current thread. On both aarch64 and x86-64, there is (expectedly) pretty much no performance hit. I didn't have any 32-bit platforms to test the seqlock performance on, so I did the next best thing and just forced the 64-bit platforms to use the seqlock implementation. There, the performance degraded by ~1-2ns/(lock+unlock) on x86-64 and ~6-8ns/(lock+unlock) on aarch64, which is measurable but seems acceptable to me seeing as 32-bit platforms should be a small minority anyways.
cc `@joboet` `@RalfJung` `@CAD97`
This changes `ReentrantLock` to use `ThreadId` for the thread ownership check instead of the address of a thread local. Unlike TLS blocks, `ThreadId` is guaranteed to be unique across the lifetime of the process, so if any thread ever terminates while holding a `ReentrantLockGuard`, no other thread may ever acquire that lock again.
On platforms with 64-bit atomics, this is a very simple change. On other platforms, the approach used is slightly more involved, as explained in the module comment.
This also adds a `CURRENT_ID` thread local in addition to the already existing `CURRENT`. This allows us to access the current `ThreadId` without the relatively heavy machinery used by `thread::current().id()`.
Document the column numbers for the dbg! macro
The line numbers were also made consistent, some examples used the line numbers as shown on the playground while others used the line numbers that you would expect when just seeing the documentation.
The second option was chosen to make everything consistent.
unix: break `stack_overflow::install_main_guard` into smaller fn
This was one big deeply-indented function for no reason. This made it hard to reason about the boundaries of its safety. Or just, y'know, read. Simplify it by splitting it into platform-specific functions, but which are still asked to keep compiling (a desirable property, since all of these OS use a similar API).
This is mostly a whitespace change, so I suggest reviewing it only after setting Files changed -> (the options gear) -> [x] Hide whitespace as that will make it easier to see how the code was actually broken up instead of raw line diffs.
Windows: Use futex implementation for `Once`
Keep the queue implementation for win7.
Inspired by PR #121956
<!--
If this PR is related to an unstable feature or an otherwise tracked effort,
please link to the relevant tracking issue here. If you don't know of a related
tracking issue or there are none, feel free to ignore this.
This PR will get automatically assigned to a reviewer. In case you would like
a specific user to review your work, you can assign it to them by using
r? <reviewer name>
-->
The line numbers were also made consistent, some examples used the line numbers as shown on the playground while others used the line numbers that you would expect when just seeing the documentation.
The second option was chosen to make everything consistent.
Prevent double reference in generic futex
In the Windows futex implementation we were a little lax at allowing references to references (i.e. `&&`) which can lead to deadlocks due to reading the wrong memory address. This uses a trait to tighten the constraints and ensure this doesn't happen.
r? libs
Make more Windows functions `#![deny(unsafe_op_in_unsafe_fn)]`
As part of #127747, I've evaluated some more Windows functions and added `unsafe` blocks where necessary. Some are just trivial wrappers that "inherit" the full unsafety of their function, but for others I've added some safety comments. A few functions weren't actually unsafe at all. I think they were just using `unsafe fn` to avoid an `unsafe {}` block.
I'm not touching `c.rs` yet because that is partially being addressed by another PR and also I have plans to further reduce the number of wrapper functions we have in there.
r? libs
This function is purely informative, answering where a stack starts.
This is a safe operation, even if an answer requires unsafe code,
and even if the result is some unsafe code decides to trust the answer.
It also doesn't need to fetch the PAGE_SIZE when its caller just did so!
Let's complicate its signature and in doing so simplify its operation.
This allows sprinkling around #[forbid(unsafe_op_in_unsafe_fn)]
zkvm: add `#[forbid(unsafe_op_in_unsafe_fn)]` in `stdlib`
This also adds an additional `unsafe` block to address compiler errors.
This PR is intended to address https://github.com/rust-lang/rust/issues/127747 for the zkvm target.
Use futex.rs for Windows thread parking
If I'm not overlooking anything then the Windows 10+ thread parking implementation is practically the same as the futex.rs implementation. So we may as well use the same implementation for both. The old version is still kept around for Windows 7 support.
r? ````@joboet```` if you wouldn't mind double checking I've not missed something
std: Use `read_unaligned` for reads from DWARF
There's a lot of... *stuff* going on here. Meanwhile, `read_unaligned` has been available since 1.17.0, so let's just use that.
Clean up more comments near use declarations
#125443 will reformat all use declarations in the repository. There are a few edge cases involving comments on use declarations that require care. This PR fixes them up so #125443 can go ahead with a simple `x fmt --all`. A follow-up to #126717.
r? ``@cuviper``
Simplify environment variable examples
I’ve found myself visiting the documentation for `std::env::vars` every few months, and every time I do, it is because I want to quickly get a snippet to print out all environment variables :-)
So I think it could be nice to simplify the examples a little to make them self-contained. It is of course a style question if one should import a module a not, but I personally don’t import modules used just once in a code snippet.
There are some comments describing multiple subsequent `use` items. When
the big `use` reformatting happens some of these `use` items will be
reordered, possibly moving them away from the comment. With this
additional level of formatting it's not really feasible to have comments
of this type. This commit removes them in various ways:
- merging separate `use` items when appropriate;
- inserting blank lines between the comment and the first `use` item;
- outright deletion (for comments that are relatively low-value);
- adding a separate "top-level" comment.
We also entirely skip formatting for four library files that contain
nothing but `pub use` re-exports, where reordering would be painful.
Make os/windows and pal/windows default to `#![deny(unsafe_op_in_unsafe_fn)]`
This is to prevent regressions in modules that currently pass. I did also fix up a few trivial places where the module contained only one or two simple wrappers. In more complex cases we should try to ensure the `unsafe` blocks are appropriately scoped and have any appropriate safety comments.
This does not fix the windows bits of #127747 but it should help prevent regressions until that is done and also make it more obvious specifically which modules need attention.
std: `#![deny(unsafe_op_in_unsafe_fn)]` in platform-independent code
This applies the `unsafe_op_in_unsafe_fn` lint in all places in std that _do not have platform-specific cfg in their code_. For all such places, the lint remains allowed, because they need further work to address the relevant concerns. This list includes:
- `std::backtrace_rs` (internal-only)
- `std::sys` (internal-only)
- `std::os`
Notably this eliminates all "unwrapped" unsafe operations in `std::io` and `std::sync`, which will make them much more auditable in the future. Such has *also* been left for future work. While I made a few safety comments along the way on interfaces I have grown sufficiently familiar with, in most cases I had no context, nor particular confidence the unsafety was correct.
In the cases where I was able to determine the unsafety was correct without having prior context, it was obviously redundant. For example, an unsafe function calling another unsafe function that has the exact same contract, forwarding its caller's requirements just as it forwards its actual call.
Windows: Remove some unnecessary type aliases
Back in the olden days, C did not have fixed-width types so these type aliases were at least potentially useful. Nowadays, and especially in Rust, we don't need the aliases and they don't help with anything. Notably the windows bindings we use also don't bother with the aliases. And even when we have used aliases they're often only used once then forgotten about.
The only one that gives me pause is `DWORD` because it's used a fair bit. But it's still used inconsistently and we implicitly assume it's a `u32` anyway (e.g. `as` casting from an `i32`).
std: removes logarithms family function edge cases handling for solaris.
Issue had been fixed over time with solaris, 11.x behaves correctly
(and we support it as minimum), illumos works correctly too.
Merge Apple `std::os` extensions modules into `std::os::darwin`
The functionality available on Apple platforms are very similar, and were (basically) duplicated for each platform.
This PR rectifies that by merging the code into one module.
Ultimately, I've done this to fix `./x build library --target=aarch64-apple-tvos,aarch64-apple-watchos,aarch64-apple-visionos`, as that currently fails because of dead code warnings.
Publically exposing these to tvOS/watchOS/visionOS targets is considered in https://github.com/rust-lang/rust/pull/123723, but that seems to be dragging out, and in any case I think it makes sense to do the refactor separately from stabilization.
r? libs
Fixes https://github.com/rust-lang/rust/issues/121640 and https://github.com/rust-lang/rust/issues/124825.
The functionality available on Apple platforms are very similar, and
were duplicated for each platform.
Additionally, this fixes a warning when compiling the standard library
for tvOS, watchOS and visionOS by marking the corresponding code as
dead code.
Use ManuallyDrop in BufWriter::into_parts
The fact that `mem::forget` takes by value means that it interacts very poorly with Stacked Borrows; generally users think of calling it as a no-op, but in Stacked Borrows, the field retagging tends to cause surprise tag invalidation.
Remove memory leaks in doctests in `core`, `alloc`, and `std`
cc `@RalfJung` https://github.com/rust-lang/rust/issues/126067https://github.com/rust-lang/miri/issues/3670
Should be no actual *documentation* changes[^1], all added/modified lines in the doctests are hidden with `#`,
This PR splits the existing memory leaks in doctests in `core`, `alloc`, and `std` into two general categories:
1. "Non-focused" memory leaks that are incidental to the thing being documented, and/or are easy to remove, i.e. they are only there because preventing the leak would make the doctest less clear and/or concise.
- These doctests simply have a comment like `# // Prevent leaks for Miri.` above the added line that removes the memory leak.
- [^2]Some of these would perhaps be better as part of the public documentation part of the doctest, to clarify that a memory leak can happen if it is not otherwise mentioned explicitly in the documentation (specifically the ones in `(A)Rc::increment_strong_count(_in)`).
2. "Focused" memory leaks that are intentional and documented, and/or are possibly fragile to remove.
- These doctests have a `# // FIXME` comment above the line that removes the memory leak, with a note that once `-Zmiri-disable-leak-check` can be applied at test granularity, these tests should be "un-unleakified" and have `-Zmiri-disable-leak-check` enabled.
- Some of these are possibly fragile (e.g. unleaking the result of `Vec::leak`) and thus should definitely not be made part of the documentation.
This should be all of the leaks currently in `core` and `alloc`. I only found one leak in `std`, and it was in the first category (excluding the modules `@RalfJung` mentioned in https://github.com/rust-lang/rust/issues/126067 , and reducing the number of iterations of [one test](https://github.com/rust-lang/rust/blob/master/library/std/src/sync/once_lock.rs#L49-L94) from 1000 to 10)
[^1]: assuming [^2] is not added
[^2]: backlink
Windows: Add experimental support for linking std-required system DLLs using raw-dylib
For Windows, this allows std to define system imports without needing the user to have import libraries. It's intended for this to become the default.
For now it's an experimental feature so it can be tested using build-std.
fix interleaved output in the default panic hook when multiple threads panic simultaneously
previously, we only held a lock for printing the backtrace itself. since all threads were printing to the same file descriptor, that meant random output in the default panic hook from one thread would be interleaved with the backtrace from another. now, we hold the lock for the full duration of the hook, and the output is ordered.
---
i noticed some odd things while working on this you may or may not already be aware of.
- libbacktrace is included as a submodule instead of a normal rustc crate, and as a result uses `cfg(backtrace_in_std)` instead of a more normal `cfg(feature = "rustc-dep-of-std")`. probably this is left over from before rust used a cargo-based build system?
- the default panic handler uses `trace_unsynchronized`, etc, in `sys::backtrace::print`. as a result, the lock only applies to concurrent *panic handlers*, not concurrent *threads*. in other words, if another, non-panicking, thread tried to print a backtrace at the same time as the panic handler, we may have UB, especially on windows.
- we have the option of changing backtrace to enable locking when `backtrace_in_std` is set so we can reuse their lock instead of trying to add our own.
Guard against calling `libc::exit` multiple times on Linux.
Mitigates (but does not fix) #126600 by ensuring only one thread which calls Rust `exit` actually calls `libc::exit`, and all other callers of Rust `exit` block.
previously, we only held a lock for printing the backtrace itself. since all threads were printing to the same file descriptor, that meant random output in the default panic hook would be interleaved with the backtrace. now, we hold the lock for the full duration of the hook, and the output is ordered.
Use pidfd_spawn for faster process spawning when a PidFd is requested
glibc 2.39 added `pidfd_spawnp` and `pidfd_getpid` which makes it possible to get pidfds while staying on the CLONE_VFORK path.
verified that vfork gets used with strace:
```
$ strace -ff -e pidfd_open,clone3,openat,execve,waitid,close ./x test std --no-doc -- pidfd
[...]
[pid 2820532] clone3({flags=CLONE_VM|CLONE_PIDFD|CLONE_VFORK|CLONE_CLEAR_SIGHAND, pidfd=0x7b7f885fec6c, exit_signal=SIGCHLD, stack=0x7b7f88aff000, stack_size=0x9000}strace: Process 2820533 attached
<unfinished ...>
[pid 2820533] execve("/home/the8472/bin/sleep", ["sleep", "1000"], 0x7ffdd0e268d8 /* 107 vars */) = -1 ENOENT (No such file or directory)
[pid 2820533] execve("/home/the8472/.cargo/bin/sleep", ["sleep", "1000"], 0x7ffdd0e268d8 /* 107 vars */) = -1 ENOENT (No such file or directory)
[pid 2820533] execve("/usr/local/bin/sleep", ["sleep", "1000"], 0x7ffdd0e268d8 /* 107 vars */) = -1 ENOENT (No such file or directory)
[pid 2820533] execve("/usr/bin/sleep", ["sleep", "1000"], 0x7ffdd0e268d8 /* 107 vars */ <unfinished ...>
[pid 2820532] <... clone3 resumed> => {pidfd=[3]}, 88) = 2820533
[pid 2820533] <... execve resumed>) = 0
[pid 2820532] openat(AT_FDCWD, "/proc/self/fdinfo/3", O_RDONLY|O_CLOEXEC) = 4
[pid 2820532] close(4) = 0
```
Tracking issue: #82971
std: Set `has_reliable_f16` to false for MIPS targets in build.rs
This PR makes std tests link for MIPS again (they broke with https://github.com/rust-lang/rust/pull/126608) by avoiding the following link errors. Step-by-step instructions on how to reproduce these errors in docker can be found below.
std.9e27ea-cgu.12:(.text._ZN3std3num8test_num17edc3E+0x38): undefined reference to `__gnu_f2h_ieee'
std.9e27ea-cgu.12:(.text._ZN3std3num8test_num17hdc3E+0x38): undefined reference to `__gnu_h2f_ieee'
This PR just adds one line of config in existing f16 infrastructure. It also disables four doctests that fails with the same link errors.
## Step-by-step to reproduce linking error
1. Prepare:
```sh
docker run -it ubuntu:24.10
apt update && apt install -y \
libc6-mips-cross \
libc6-mipsel-cross \
libc6-mips64-cross \
libc6-mips64el-cross \
gcc-mips-linux-gnu \
gcc-mipsel-linux-gnu \
gcc-mips64-linux-gnuabi64 \
gcc-mips64el-linux-gnuabi64 \
git curl python3 build-essential
git clone --depth 1 https://github.com/rust-lang/rust.git
cd rust
```
2. Try to link std tests for any of these 4 MIPS targets by running any one of these commands:
```sh
CC_mips_unknown_linux_gnu=mips-linux-gnu-gcc \
CARGO_TARGET_MIPS_UNKNOWN_LINUX_GNU_LINKER=mips-linux-gnu-gcc \
./x test library/std --target mips-unknown-linux-gnu
CC_mipsel_unknown_linux_gnu=mipsel-linux-gnu-gcc \
CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_GNU_LINKER=mipsel-linux-gnu-gcc \
./x test library/std --target mipsel-unknown-linux-gnu
CC_mips64_unknown_linux_gnuabi64=mips64-linux-gnuabi64-gcc \
CARGO_TARGET_MIPS64_UNKNOWN_LINUX_GNUABI64_LINKER=mips64-linux-gnuabi64-gcc \
./x test library/std --target mips64-unknown-linux-gnuabi64
CC_mips64el_unknown_linux_gnuabi64=mips64el-linux-gnuabi64-gcc \
CARGO_TARGET_MIPS64EL_UNKNOWN_LINUX_GNUABI64_LINKER=mips64el-linux-gnuabi64-gcc \
./x test library/std --target mips64el-unknown-linux-gnuabi64
```
### Expected
No link error. After this PR there are no link errors.
### Actual
```
error: linking with `mips-linux-gnu-gcc` failed: exit status: 1
|
= note: LC_ALL="C" PATH="/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin:/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin:/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" VSLANG="1033" "mips-linux-gnu-gcc" "/tmp/rustcEtKsay/symbols.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.00.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.01.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.02.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.03.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.04.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.05.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.06.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.07.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.08.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.09.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.10.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.11.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.12.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.13.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.14.rcgu.o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.15.rcgu.o" "-Wl,--as-needed" "-L" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps" "-L" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/release/deps" "-L" "/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/mips-unknown-linux-gnu/lib" "-Wl,-Bstatic" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/librand_xorshift-deb32232a867c543.rlib" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/librand-5a391600dce9d98f.rlib" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/librand_core-a11cfba3d86c5298.rlib" "/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/mips-unknown-linux-gnu/lib/libtest-65b05caf5a9b99a4.rlib" "/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/mips-unknown-linux-gnu/lib/libgetopts-ba692b2f798aef60.rlib" "/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/mips-unknown-linux-gnu/lib/libunicode_width-20ec8b475126cb0b.rlib" "/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/mips-unknown-linux-gnu/lib/librustc_std_workspace_std-c17f739fee51cc86.rlib" "-L" "/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/mips-unknown-linux-gnu/lib" "-Wl,-Bdynamic" "-lstd-124ee57a4c00deda" "-Wl,-Bstatic" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/libcompiler_builtins-bd55a137b89bc81f.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "/rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/mips-unknown-linux-gnu/lib" "-o" "/rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-Wl,-O1" "-nodefaultlibs" "-Wl,-z,origin" "-Wl,-rpath,$ORIGIN/../lib"
= note: /usr/lib/gcc-cross/mips-linux-gnu/12/../../../../mips-linux-gnu/bin/ld: /rust/build/x86_64-unknown-linux-gnu/stage1-std/mips-unknown-linux-gnu/release/deps/std-1cffa50fa8c43b63.std.9ee227e919a554fa-cgu.12.rcgu.o: in function `std::num::test_num':
std.9ee227e919a554fa-cgu.12:(.text._ZN3std3num8test_num17haed2ea710c1afdc3E+0x38): undefined reference to `__gnu_f2h_ieee'
/usr/lib/gcc-cross/mips-linux-gnu/12/../../../../mips-linux-gnu/bin/ld: std.9ee227e919a554fa-cgu.12:(.text._ZN3std3num8test_num17haed2ea710c1afdc3E+0x3c): undefined reference to `__gnu_f2h_ieee'
/usr/lib/gcc-cross/mips-linux-gnu/12/../../../../mips-linux-gnu/bin/ld: std.9ee227e919a554fa-cgu.12:(.text._ZN3std3num8test_num17haed2ea710c1afdc3E+0x44): undefined reference to `__gnu_h2f_ieee'
...
collect2: error: ld returned 1 exit status
error: could not compile `std` (lib test) due to 1 previous error
```
clarify `sys::unix::fd::FileDesc::drop` comment
closes#66876
simply clarifies some resource-relevant things regarding the `close` syscall to reduce the amount of search needed in other parts of the web.
once_lock: make test not take as long in Miri
Allocating 1000 list elements takes a while (`@zachs18` reported >5min), so let's reduce the iteration count when running in Miri. Unfortunately due to this clever `while let i @ 0..LEN =` thing, the count needs to be a constants, and constants cannot be shadowed, so we need to use another trick to hide the `cfg!(miri)` from the docs. (I think this loop condition may be a bit too clever, it took me a bit to decipher. Ideally this would be `while let i = ... && i < LEN`, but that is not stable yet.)
Improve std::Path's Hash quality by avoiding prefix collisions
This adds a bit rotation to the already existing state so that the same sequence of characters chunked at different offsets into separate path components results in different hashes.
The tests are from #127255Closes#127254
Update windows-bindgen to 0.58.0
This also switches from the bespoke `std` generated bindings to the normal `sys` ones everyone else uses.
This has almost no difference except that the `sys` bindings use the `windows_targets::links!` macro for FFI imports, which we implement manually. This does cause the diff to look much larger than it really is but the bulk of the changes are mostly contained to the generated code.
Remove unqualified form import of io::Error in process_vxworks.rs and fallback on remove_dir_impl for vxworks
Hi all,
This is to address issue #127084. On inspections it was found that io::Error refrences were all of qualified form and there was no need to add a unqualified form import. Also to successfully build rust for vxworks, we need to fallback on the remove_impl_dir implementations.
Thank you.
To avoid this linker error:
$ sudo apt install libc6-mips-cross gcc-mips-linux-gnu
$ CC_mips_unknown_linux_gnu=mips-linux-gnu-gcc \
CARGO_TARGET_MIPS_UNKNOWN_LINUX_GNU_LINKER=mips-linux-gnu-gcc \
./x test library/std --target mips-unknown-linux-gnu
undefined reference to `__gnu_f2h_ieee'
You get the same linker error also with mipsel, mips64 and
mips64el toolchains.
The target_arch of `powerpc64le` is `powerpc64`, so
`powerpc64le` can be removed from a match arm in build.rs
related to f16.
You can check available `target_arch`:s with:
$ rustc +nightly -Zunstable-options --print all-target-specs-json \
| grep powerpc | grep arch | sort | uniq
"arch": "powerpc",
"arch": "powerpc64",
Stabilize `PanicInfo::message()` and `PanicMessage`
Resolves#66745
This stabilizes the [`PanicInfo::message()`](https://doc.rust-lang.org/nightly/core/panic/struct.PanicInfo.html#method.message) and [`PanicMessage`](https://doc.rust-lang.org/nightly/core/panic/struct.PanicMessage.html).
Demonstration of [custom panic handler](https://github.com/StackOverflowExcept1on/panicker):
```rust
#![no_std]
#![no_main]
extern crate libc;
#[no_mangle]
extern "C" fn main() -> libc::c_int {
panic!("I just panic every time");
}
#[panic_handler]
fn my_panic(panic_info: &core::panic::PanicInfo) -> ! {
use arrayvec::ArrayString;
use core::fmt::Write;
let message = panic_info.message();
let location = panic_info.location().unwrap();
let mut debug_msg = ArrayString::<1024>::new();
let _ = write!(&mut debug_msg, "panicked with '{message}' at '{location}'");
if debug_msg.try_push_str("\0").is_ok() {
unsafe {
libc::puts(debug_msg.as_ptr() as *const _);
}
}
unsafe { libc::exit(libc::EXIT_FAILURE) }
}
```
```
$ cargo +stage1 run --release
panicked with 'I just panic every time' at 'src/main.rs:8:5'
```
- [x] FCP: https://github.com/rust-lang/rust/issues/66745#issuecomment-2198143725
r? libs-api
Cleanup bootstrap check-cfg
This PR cleanup many custom `check-cfg` in bootstrap that have been accumulated over the years.
As well as updating some outdated comments.
std: separate TLS key creation from TLS access
Currently, `std` performs an atomic load to get the OS key on every access to `StaticKey` even when the key is already known. This PR thus replaces `StaticKey` with the platform-specific `get` and `set` function and a new `LazyKey` type that acts as a `LazyLock<Key>`, allowing the reuse of the retreived key for multiple accesses.
Related to #110897.
Add more constants, functions, and tests for `f16` and `f128`
This adds everything that was in some way blocked on const eval, since https://github.com/rust-lang/rust/pull/126429 landed. There is a lot of `cfg(bootstrap)` since that is a fairly recent change.
`f128` tests are disabled on everything except x86_64 and Linux aarch64, which are two platforms I know have "good" support for these types - meaning basic math symbols are available and LLVM doesn't hit selection crashes. `f16` tests are enabled on almost everything except for known LLVM crashes. Doctests are only enabled on x86_64.
Tracking issue: https://github.com/rust-lang/rust/issues/116909
Currently, `std` performs an atomic load to get the OS key on every access to `StaticKey` even when the key is already known. This PR thus replaces `StaticKey` with the platform-specific `get` and `set` function and a new `LazyKey` type that acts as a `LazyLock<Key>`, allowing the reuse of the retreived key for multiple accesses.
This suite tests all library functions that are now available for the
types. Tests are only run on certain platforms where `f16` and `f128`
are known to work (have symbols available and don't crash LLVM).
This adds everything that was directly or transitively blocked on const
arithmetic for these types, which was recently merged.
Since const arithmetic is recent, most of these need to be gated by
`bootstrap`.
Anything that relies on intrinsics that are still missing is excluded.
There are some complexities about what platforms we can test f16 and
f128 on. Put this in build.rs so we have an easy way to configure tests
with a single attribute, and keep it up to date.
Remove `MaybeUninit::uninit_array()` and replace it with inline const blocks.
\[This PR originally contained the changes in #125995 too. See edit history for the original PR description.]
The documentation of `MaybeUninit::uninit_array()` says:
> Note: in a future Rust version this method may become unnecessary when Rust allows [inline const expressions](https://github.com/rust-lang/rust/issues/76001). The example below could then use `let mut buf = [const { MaybeUninit::<u8>::uninit() }; 32];`.
The PR adding it also said: <https://github.com/rust-lang/rust/pull/65580#issuecomment-544200681>
> if it’s stabilized soon enough maybe it’s not worth having a standard library method that will be replaceable with `let buffer = [MaybeUninit::<T>::uninit(); $N];`
That time has come to pass — inline const expressions are stable — so `MaybeUninit::uninit_array()` is now unnecessary. The only remaining question is whether it is an important enough *convenience* to keep it around.
I believe it is net good to remove this function, on the principle that it is better to compose two orthogonal features (`MaybeUninit` and array construction) than to have a specific function for the specific combination, now that that is possible.
This is possible now that inline const blocks are stable; the idea was
even mentioned as an alternative when `uninit_array()` was added:
<https://github.com/rust-lang/rust/pull/65580#issuecomment-544200681>
> if it’s stabilized soon enough maybe it’s not worth having a
> standard library method that will be replaceable with
> `let buffer = [MaybeUninit::<T>::uninit(); $N];`
Const array repetition and inline const blocks are now stable (in the
next release), so that circumstance has come to pass, and we no longer
have reason to want `uninit_array()` other than convenience. Therefore,
let’s evaluate the inconvenience by not using `uninit_array()` in
the standard library, before potentially deleting it entirely.
std: refactor the TLS implementation
As discovered by Mara in #110897, our TLS implementation is a total mess. In the past months, I have simplified the actual macros and their expansions, but the majority of the complexity comes from the platform-specific support code needed to create keys and register destructors. In keeping with #117276, I have therefore moved all of the `thread_local_key`/`thread_local_dtor` modules to the `thread_local` module in `sys` and merged them into a new structure, so that future porters of `std` can simply mix-and-match the existing code instead of having to copy the same (bad) implementation everywhere. The new structure should become obvious when looking at `sys/thread_local/mod.rs`.
Unfortunately, the documentation changes associated with the refactoring have made this PR rather large. That said, this contains no functional changes except for two small ones:
* the key-based destructor fallback now, by virtue of sharing the implementation used by macOS and others, stores its list in a `#[thread_local]` static instead of in the key, eliminating one indirection layer and drastically simplifying its code.
* I've switched over ZKVM (tier 3) to use the same implementation as WebAssembly, as the implementation was just a way worse version of that
Please let me know if I can make this easier to review! I know these large PRs aren't optimal, but I couldn't think of any good intermediate steps.
`@rustbot` label +A-thread-locals
std::unix::fs: copy simplification for apple.
since we do support from macOs Sierra, we avoid the little runtime overhead with the fclonefileat symbol check.
Remove use of const traits (and `feature(effects)`) from stdlib
The current uses are already unsound because they are using non-const impls in const contexts. We can reintroduce them by reverting the commit in this PR, after #120639 lands.
Also, make `effects` an incomplete feature.
cc `@rust-lang/project-const-traits`
r? `@compiler-errors`
Add PidFd::{kill, wait, try_wait}
#117957 changed `Child` kill/wait/try_wait to use its pidfd instead of the pid, when one is available.
This PR extracts those implementations and makes them available on `PidFd` directly.
The `PidFd` implementations differ significantly from the corresponding `Child` methods:
* the methods can be called after the child has been reaped, which will result in an error but will be safe. This state is not observable in `Child` unless something stole the zombie child
* the `ExitStatus` is not kept, meaning that only the first time a wait succeeds it will be returned
* `wait` does not close stdin
* `wait` only requires `&self` instead of `&mut self` since there is no state to maintain and subsequent calls are safe
Tracking issue: #82971
As long as a pidfd is on a child it can be safely reaped. Taking it
would mean the child would now have to be awaited through its pid, but could also
be awaited through the pidfd. This could then suffer from a recycling race.
Most modules have such a blank line, but some don't. Inserting the blank
line makes it clearer that the `//!` comments are describing the entire
module, rather than the `use` declaration(s) that immediately follows.
This makes their intent and expected location clearer. We see some
examples where these comments were not clearly separate from `use`
declarations, which made it hard to understand what the comment is
describing.
export std::os::fd module on HermitOS
The HermitOS' IO interface is similiar to Unix. Consequently, this PR synchronize the FD implementation between both.
closes#126198
Document behavior of `create_dir_all` wrt. empty path
The behavior makes sense because `Path::new("one_component").parent() == Some(Path::new(""))`, so if one naively wants to create the parent directory for a file to be written, it simply works.
Closes#105108 by documenting the current behavior.
Bump windows-bindgen to 0.57
This PR updates our generated Windows API bindings using the latest version of `windows-bindgen`.
The only change to the generated code is that `derive` is used for `Copy` and `Clone` instead of `impl`.
As discovered by Mara in #110897, our TLS implementation is a total mess. In the past months, I have simplified the actual macros and their expansions, but the majority of the complexity comes from the platform-specific support code needed to create keys and register destructors. In keeping with #117276, I have therefore moved all of the `thread_local_key`/`thread_local_dtor` modules to the `thread_local` module in `sys` and merged them into a new structure, so that future porters of `std` can simply mix-and-match the existing code instead of having to copy the same (bad) implementation everywhere. The new structure should become obvious when looking at `sys/thread_local/mod.rs`.
Unfortunately, the documentation changes associated with the refactoring have made this PR rather large. That said, this contains no functional changes except for two small ones:
* the key-based destructor fallback now, by virtue of sharing the implementation used by macOS and others, stores its list in a `#[thread_local]` static instead of in the key, eliminating one indirection layer and drastically simplifying its code.
* I've switched over ZKVM (tier 3) to use the same implementation as WebAssembly, as the implementation was just a way worse version of that
Please let me know if I can make this easier to review! I know these large PRs aren't optimal, but I couldn't think of any good intermediate steps.
@rustbot label +A-thread-locals
Rollup of 9 pull requests
Successful merges:
- #125829 (rustc_span: Add conveniences for working with span formats)
- #126361 (Unify intrinsics body handling in StableMIR)
- #126417 (Add `f16` and `f128` inline ASM support for `x86` and `x86-64`)
- #126424 ( Also sort `crt-static` in `--print target-features` output)
- #126428 (Polish `std::path::absolute` documentation.)
- #126429 (Add `f16` and `f128` const eval for binary and unary operationations)
- #126448 (End support for Python 3.8 in tidy)
- #126488 (Use `std::path::absolute` in bootstrap)
- #126511 (.mailmap: Associate both my work and my private email with me)
r? `@ghost`
`@rustbot` modify labels: rollup
These changes bring it closer to other standard library documentation
and, in particular, `std::fs::canonicalize`, which it will often be
compared with.
* Add `# Platform-specific behavior` section, with content moved from
Examples section.
* Create `# Errors` section.
* Phrase error description to allow future platforms to have new
syntactic errors, rather than only emptiness.
* Add missing commas.
* Indent example code 4 spaces.
Rollup of 7 pull requests
Successful merges:
- #123769 (Improve escaping of byte, byte str, and c str proc-macro literals)
- #126054 (`E0229`: Suggest Moving Type Constraints to Type Parameter Declaration)
- #126135 (add HermitOS support for vectored read/write operations)
- #126266 (Unify guarantees about the default allocator)
- #126285 (`UniqueRc`: support allocators and `T: ?Sized`.)
- #126399 (extend the check for LLVM build)
- #126426 (const validation: fix ICE on dangling ZST reference)
r? `@ghost`
`@rustbot` modify labels: rollup
Unify guarantees about the default allocator
`std::alloc` said that the default allocator is unspecified for all crrate types except `cdylib` and `staticlib`. Adjust `std::alloc::System` documentation to say the same.
Fixes#125870.
add HermitOS support for vectored read/write operations
In general, the I/O interface of hermit-abi is revised and now a more POSIX-like interface. Consequently, platform abstraction layer for HermitOS has slightly adjusted and some inaccuracies remove.
Hermit is a tier 3 platform and this PR changes only files, wich are related to the tier 3 platform.
std::unix::fs::link using direct linkat call for Solaris.
Since we support solaris 11 as minimum, we can get rid of the runtime overhead.
try-job: dist-various-2
Clarify `Command::new` behavior for programs with arguments
I mistakenly passed program path along arguments as the same string into `Command::new` a couple of times now. It might be useful to explicitly highlight that `Command::new` intends to accept path to a program, not path to a program plus arguments. Also nudge the user to use `Command::arg` or `Command::args` if they wish to pass arguments.
Rollup of 16 pull requests
Successful merges:
- #123374 (DOC: Add FFI example for slice::from_raw_parts())
- #124514 (Recommend to never display zero disambiguators when demangling v0 symbols)
- #125978 (Cleanup: HIR ty lowering: Consolidate the places that do assoc item probing & access checking)
- #125980 (Nvptx remove direct passmode)
- #126187 (For E0277 suggest adding `Result` return type for function when using QuestionMark `?` in the body.)
- #126210 (docs(core): make more const_ptr doctests assert instead of printing)
- #126249 (Simplify `[T; N]::try_map` signature)
- #126256 (Add {{target}} substitution to compiletest)
- #126263 (Make issue-122805.rs big endian compatible)
- #126281 (set_env: State the conclusion upfront)
- #126286 (Make `storage-live.rs` robust against rustc internal changes.)
- #126287 (Update a cranelift patch file for formatting changes.)
- #126301 (Use `tidy` to sort crate attributes for all compiler crates.)
- #126305 (Make PathBuf less Ok with adding UTF-16 then `into_string`)
- #126310 (Migrate run make prefer rlib)
- #126314 (fix RELEASES: we do not support upcasting to auto traits)
r? `@ghost`
`@rustbot` modify labels: rollup
Make PathBuf less Ok with adding UTF-16 then `into_string`
Fixes#126291 which is, as far as I can tell, a regression introduced by #96869.
try-job: x86_64-msvc
Update a cranelift patch file for formatting changes.
PR #125443 will reformat all the use declarations in the repo. This would break a patch kept in `rustc_codegen_cranelift` that gets applied to `library/std/src/sys/pal/windows/rand.rs`.
So this commit formats the use declarations in `library/std/src/sys/pal/windows/rand.rs` in advance of #125443 and updates the patch file accordingly.
The motivation is that #125443 is a huge change and we want to get fiddly little changes like this out of the way so it can be nothing more than an `x fmt --all`.
r? ``@bjorn3``
set_env: State the conclusion upfront
People tend to skim or skip over long explanations so we should be very upfront that `set_var` and `remove_var` are being made unsafe for a very good reason.
This is just the conclusion restated almost verbatim but earlier in the docs and separated from the explanation:
0c960618b5/library/std/src/env.rs (L338-L339)
I think this may help with people who may not be entirely comfortable with #125937 being rejected.
PR #125443 will reformat all the use declarations in the repo. This
would break a patch kept in `rustc_codegen_cranelift` that gets applied
to `library/std/src/sys/pal/windows/rand.rs`.
So this commit formats the use declarations in
`library/std/src/sys/pal/windows/rand.rs` in advance of #125443 and
updates the patch file accordingly.
The motivation is that #125443 is a huge change and we want to get
fiddly little changes like this out of the way so it can be nothing more
than an `x fmt --all`.
`std::alloc` said that the default allocator is unspecified for all
crrate types except `cdylib` and `staticlib`. Adjust
`std::alloc::System` documentation to say the same.
Fixes#125870.
std::unix::os current_exe implementation simplification for haiku.
_get_net_image_info is a bit overkill as it allows to get broader informations about the process.
std::unix::fs::get_mode implementation for illumos/solaris.
they both support the F_GETFL fctnl flag/O_ACCMODE mask to get the file descriptor access modes.
In general, the I/O interface of hermit-abi is more POSIX-like
interface. Consequently, platform abstraction layer for HermitOS
has slightly adjusted and some inaccuracies remove.
Prevent copy-paste errors from producing new starved-for-resources
threaded platforms by raising `DEFAULT_MIN_STACK_SIZE` from 4096 bytes
to at least 64KiB.
Two platforms "affected" by this have no actual threads:
- UEFI
- "unsupported"
Platforms that this actually affects:
- wasm32-wasi with "atomics" enabled
- wasm32-wasi-p1-threads
Two exceptions:
- SGX: a "secure code execution" platform, stays at 4096B
- TEEOS: also a "secure code execution" platform, stays at 8192B
I believe either of these may have sufficiently "interesting" semantics
around threads, or significant external library support. Either would
mean making any choices here for them is suspect.
Rollup of 9 pull requests
Successful merges:
- #124840 (resolve: mark it undetermined if single import is not has any bindings)
- #125622 (Winnow private method candidates instead of assuming any candidate of the right name will apply)
- #125648 (Remove unused(?) `~/rustsrc` folder from docker script)
- #125672 (Add more ABI test cases to miri (RFC 3391))
- #125800 (Fix `mut` static task queue in SGX target)
- #125871 (Orphanck[old solver]: Consider opaque types to never cover type parameters)
- #125893 (Handle all GVN binops in a single place.)
- #126008 (Port `tests/run-make-fulldeps/issue-19371` to ui-fulldeps)
- #126032 (Update description of the `IsTerminal` example)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix `mut` static task queue in SGX target
[PR 125046](https://github.com/rust-lang/rust/pull/125046) prevents mutable references to statics with `#[linkage]`. Such a construct was used with the tests for the `x86_64-fortanix-unknown-sgx` target. This PR fixes this and cleans up code a bit in 5 steps. Each step passes CI:
- The `mut` static is removed, and `Task` explicitly implements `Send`
- Renaming of the `task_queue::lock` function
- Pass function for `Thread` as `Send` to `Thread::imp` and update when `Packet<'scope, T>` implements `Sync`
- Storing `Task::p` as a type that implements `Send`
- Letting the compiler auto implement `Send` for `Task`
cc: ``@jethrogb``
std::unix::fs::get_path: using fcntl codepath for netbsd instead.
on netbsd, procfs is not as central as on linux/solaris thus can be perfectly not mounted.
Thus using fcntl with F_GETPATH, the kernel deals with MAXPATHLEN internally too.
Add `size_of` and `size_of_val` and `align_of` and `align_of_val` to the prelude
(Note: need to update the PR to add `align_of` and `align_of_val`, and remove the second commit with the myriad changes to appease the lint.)
Many, many projects use `size_of` to get the size of a type. However,
it's also often equally easy to hardcode a size (e.g. `8` instead of
`size_of::<u64>()`). Minimizing friction in the use of `size_of` helps
ensure that people use it and make code more self-documenting.
The name `size_of` is unambiguous: the name alone, without any prefix or
path, is self-explanatory and unmistakeable for any other functionality.
Adding it to the prelude cannot produce any name conflicts, as any local
definition will silently shadow the one from the prelude. Thus, we don't
need to wait for a new edition prelude to add it.
Fix typo in the docs of `HashMap::raw_entry_mut`
<!--
If this PR is related to an unstable feature or an otherwise tracked effort,
please link to the relevant tracking issue here. If you don't know of a related
tracking issue or there are none, feel free to ignore this.
This PR will get automatically assigned to a reviewer. In case you would like
a specific user to review your work, you can assign it to them by using
r? <reviewer name>
-->
Explain differences between `{Once,Lazy}{Cell,Lock}` types
The question of "which once-ish cell-ish type should I use?" has been raised multiple times, and is especially important now that we have stabilized the `LazyCell` and `LazyLock` types. The answer for the `Lazy*` types is that you would be better off using them if you want to use what is by far the most common pattern: initialize it with a single nullary function that you would call at every `get_or_init` site. For everything else there's the `Once*` types.
"For everything else" is a somewhat weak motivation, as it only describes by negation. While contrasting them is inevitable, I feel positive motivations are more understandable. For this, I now offer a distinct example that helps explain why `OnceLock` can be useful, despite `LazyLock` existing: you can do some cool stuff with it that `LazyLock` simply can't support due to its mere definition.
The pair of `std::sync::*Lock`s are usable inside a `static`, and can serve roles in async or multithreaded (or asynchronously multithreaded) programs that `*Cell`s cannot. Because of this, they received most of my attention.
Fixes#124696Fixes#125615
Change pedantically incorrect OnceCell/OnceLock wording
While the semantic intent of a OnceCell/OnceLock is that it can only be written to once (upon init), the fact of the matter is that both these types offer a `take(&mut self) -> Option<T>` mechanism that, when successful, resets the cell to its initial state, thereby [technically allowing it to be written to again](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=415c023a6ae1ef35f371a2d3bb1aa735)
Despite the fact that this can only happen with a mutable reference (generally only used during the construction of the OnceCell/OnceLock), it would be incorrect to say that the type itself as a whole *categorically* prevents being initialized or written to more than once (since it is possible to imagine an identical type only without the `take()` method that actually fulfills that contract).
To clarify, change "that cannot be.." to "that nominally cannot.." and add a note to OnceCell about what can be done with an `&mut Self` reference.
```@rustbot``` label +A-rustdocs
Make TLS accessors closures that return pointers
The current TLS macros generate a function that returns an `Option<&'static T>`. This is both risky as we lie about lifetimes, and necessitates that those functions are `unsafe`. By returning a `*const T` instead, the accessor function do not have safety requirements any longer and can be made closures without hassle. This PR does exactly that!
For native TLS, the closure approach makes it trivial to select the right accessor function at compile-time, which could result in a slight speed-up (I have the hope that the accessors are now simple enough for the MIR-inliner to kick in).
on netbsd, procfs is not as central as on linux/solaris thus
can be perfectly not mounted.
Thus using fcntl with F_GETPATH, the kernel deals with MAXPATHLEN
internally too.
While slightly verbose, it helps explain "why bother with OnceLock?"
This is a point of confusion that has been raised multiple times
shortly before and after the stabilization of LazyLock.
This example is spiritually an example of LazyLock, as it computes a
variable at runtime but accepts no inputs into that process.
It is also slightly simpler and thus easier to understand.
Change it to an even-more concise version and move it to LazyLock.
The example now editorializes slightly more. This may be unnecessary,
but it can be educational for the reader.
std::pal::unix::thread fetching min stack size on netbsd.
PTHREAD_STACK_MIN is not defined however sysconf/_SC_THREAD_STACK_MIN returns it as it can vary from arch to another.
Make `std::env::{set_var, remove_var}` unsafe in edition 2024
Allow calling these functions without `unsafe` blocks in editions up until 2021, but don't trigger the `unused_unsafe` lint for `unsafe` blocks containing these functions.
Fixes#27970.
Fixes#90308.
CC #124866.
Allow calling these functions without `unsafe` blocks in editions up
until 2021, but don't trigger the `unused_unsafe` lint for `unsafe`
blocks containing these functions.
Fixes#27970.
Fixes#90308.
CC #124866.
Make more of the test suite run on Mac Catalyst
Combined with https://github.com/rust-lang/rust/pull/125225, the only failing parts of the test suite are in `tests/rustdoc-js`, `tests/rustdoc-js-std` and `tests/debuginfo`. Tested with:
```console
./x test --target=aarch64-apple-ios-macabi library/std
./x test --target=aarch64-apple-ios-macabi --skip=tests/rustdoc-js --skip=tests/rustdoc-js-std --skip=tests/debuginfo tests
```
Will probably put up a PR later to enable _running_ on (not just compiling for) Mac Catalyst in CI, though not sure where exactly I should do so? `src/ci/github-actions/jobs.yml`?
Note that I've deliberately _not_ enabled stack overflow handlers on iOS/tvOS/watchOS/visionOS (see https://github.com/rust-lang/rust/issues/25872), but rather just skipped those tests, as it uses quite a few APIs that I'd be weary about getting rejected by the App Store (note that Swift doesn't do it on those platforms either).
r? ``@workingjubilee``
CC ``@thomcc``
``@rustbot`` label O-ios O-apple
This adds the `only-apple`/`ignore-apple` compiletest directive, and
uses that basically everywhere instead of `only-macos`/`ignore-macos`.
Some of the updates in `run-make` are a bit redundant, as they use
`ignore-cross-compile` and won't run on iOS - but using Apple in these
is still more correct, so I've made that change anyhow.
Less syscalls for the `copy_file_range` probe
If it's obvious from the actual syscall results themselves that the syscall is supported or unsupported, don't do an extra syscall with an invalid file descriptor.
CC #122052
Panic if `PathBuf::set_extension` would add a path separator
This is likely never intended and potentially a security vulnerability if it happens.
I'd guess that it's mostly literal strings that are passed to this function in practice, so I'm guessing this doesn't break anyone.
CC #125060
While the semantic intent of a OnceCell/OnceLock is that it can only be written
to once (upon init), the fact of the matter is that both these types offer a
`take(&mut self) -> Option<T>` mechanism that, when successful, resets the cell
to its initial state, thereby technically allowing it to be written to again.
Despite the fact that this can only happen with a mutable reference (generally
only used during the construction of the OnceCell/OnceLock), it would be
incorrect to say that the type itself as a whole categorically prevents being
initialized or written to more than once (since it is possible to imagine an
identical type only without the `take()` method that actually fulfills that
contract).
To clarify, change "that cannot be.." to "that nominally cannot.." and add a
note to OnceCell about what can be done with an `&mut Self` reference.
Rollup of 6 pull requests
Successful merges:
- #125263 (rust-lld: fallback to rustc's sysroot if there's no path to the linker in the target sysroot)
- #125345 (rustc_codegen_llvm: add support for writing summary bitcode)
- #125362 (Actually use TAIT instead of emulating it)
- #125412 (Don't suggest adding the unexpected cfgs to the build-script it-self)
- #125445 (Migrate `run-make/rustdoc-with-short-out-dir-option` to `rmake.rs`)
- #125452 (Cleanup check-cfg handling in core and std)
r? `@ghost`
`@rustbot` modify labels: rollup
Cleanup check-cfg handling in core and std
Follow-up to https://github.com/rust-lang/rust/pull/125296 where we:
- expect any feature cfg in std, due to `#[path]` imports
- move some check-cfg args inside the `build.rs` as per Cargo recommendation
- and replace the fake Cargo feature `"restricted-std"` by the custom cfg `restricted_std`
Fixes https://github.com/rust-lang/rust/pull/125296#issuecomment-2127009301
r? `@bjorn3` (maybe, feel free to re-roll)
I’ve found myself visiting the documentation for `std::env::vars`
every few months, and every time I do, it is because I want to quickly
get a snippet to print out all environment variables :-)
So I think it could be nice to simplify the examples a little to make
them self-contained. It is of course a style question if one should
import a module a not, but I personally don’t import modules used just
once in a code snippet.
Use functions from `crt_externs.h` on iOS/tvOS/watchOS/visionOS
Use `_NSGetEnviron`, `_NSGetArgc` and `_NSGetArgv` on iOS/tvOS/watchOS/visionOS, see each commit and the code comments for details. This allows us to unify more code with the macOS implementation, as well as avoiding linking to the `Foundation` framework (which is good for startup performance).
The biggest problem with doing this would be if it lead to App Store rejections. After doing a bunch of research on this, while [it did happen once in 2009](https://blog.unity.com/engine-platform/unity-app-store-submissions-problem-solved), I find it fairly unlikely to happen nowadays, especially considering that Apple has later _added_ `crt_externs.h` to the iOS/tvOS/watchOS/visionOS SDKs, strongly signifying the functions therein is indeed supported on those platforms (even though they lack an availability attribute).
That we've been overly cautious here has also been noted by `@thomcc` in https://github.com/rust-lang/rust/pull/117910#issuecomment-1903372350.
r? `@workingjubilee`
`@rustbot` label O-apple
Add opt-for-size core lib feature flag
Adds a feature flag to the core library that enables the possibility to have smaller implementations for certain algorithms.
So far, the core lib has traded performance for binary size. This is likely what most people want since they have big simd-capable machines. However, people on small machines, like embedded devices, don't enjoy the potential speedup of the bigger algorithms, but do have to pay for them. These microcontrollers often only have 16-1024kB of flash memory.
This PR is the result of some talks with project members like `@Amanieu` at RustNL.
There are some open questions of how this is eventually stabilized, but it's a similar question as with the existing `panic_immediate_abort` feature.
Speaking as someone from the embedded side, we'd rather have this unstable for a while as opposed to not having it at all. In the meantime we can try to use it and also add additional PRs to the core lib that uses the feature flag in areas where we find benefit.
Open questions from my side:
- Is this a good feature name?
- `panic_immediate_abort` is fairly verbose, so I went with something equally verbose
- It's easy to refactor later
- I've added the feature to `std` and `alloc` as well as they might benefit too. Do we agree?
- I expect these to get less usage out of the flag since most size-constraint projects don't use these libraries often.
The behavior makes sense because `Path::new("one_component").parent() ==
Some(Path::new(""))`, so if one naively wants to create the parent
directory for a file to be written, it simply works.
Closes#105108 by documenting the current behavior.
switch to the default implementation of `write_vectored`
HermitOS doesn't support write_vectored and switch to the default implementation of `write_vectored`.
Fix `read_exact` and `read_buf_exact` for `&[u8]` and `io:Cursor`
- Drain after `read_exact` and `read_buf_exact`
- Append to cursor in `read_buf_exact`
revise the interpretation of ReadDir for HermitOS
HermitOS supports getdents64. As under Linux, the dirent64 entry `d_off` is not longer used, because its definition is not clear. Instead of `d_off` the entry `d_reclen` is used to determine the end of the dirent64 entry.
In addition, take up `@workingjubilee` suggestion from the discussions in rust-lang/rust#115984 to increase the readability.
Hermit is a tier 3 platform and this PR changes only files, wich are related to the tier 3 platform.
Update documentation related to the recent cmd.exe fix
Fix some grammar nits, change `bat` (extension) -> `batch` (file), and make line wrapping more consistent.
If we're comfortable using `_NSGetEnviron` from `crt_externs.h`, there shouldn't be an issue with using these either, and then we can merge with the macOS implementation.
This also fixes two test cases on Mac Catalyst:
- `tests/ui/command/command-argv0.rs`, maybe because `[[NSProcessInfo processInfo] arguments]` somehow converts the name of the first argument?
- `tests/ui/env-funky-keys.rs` since we no longer link to Foundation.
Many, many projects use `size_of` to get the size of a type. However,
it's also often equally easy to hardcode a size (e.g. `8` instead of
`size_of::<u64>()`). Minimizing friction in the use of `size_of` helps
ensure that people use it and make code more self-documenting.
The name `size_of` is unambiguous: the name alone, without any prefix or
path, is self-explanatory and unmistakeable for any other functionality.
Adding it to the prelude cannot produce any name conflicts, as any local
definition will silently shadow the one from the prelude. Thus, we don't
need to wait for a new edition prelude to add it.
Add `size_of_val`, `align_of`, and `align_of_val` as well, with similar
justification: widely useful, self-explanatory, unmistakeable for
anything else, won't produce conflicts.
This is likely never intended and potentially a security vulnerability
if it happens.
I'd guess that it's mostly literal strings that are passed to this
function in practice, so I'm guessing this doesn't break anyone.
CC #125060
std::alloc: use posix_memalign instead of memalign on solarish
`memalign` on Solarish requires the alignment to be at least the size of a pointer, which we did not honor. `posix_memalign` also requires that, but that code path already takes care of this requirement.
close GH-124787
