To make way for a new IoSlice(Mut)::advance function that advances a
single slice.
Also changes the signature to accept a `&mut &mut [IoSlice]`, not
returning anything. This will better match the future IoSlice::advance
function.
Add #[track_caller] to panic_any
Report the panic location from the user code.
```rust
use std::panic;
use std::panic::panic_any;
fn main() {
panic::set_hook(Box::new(|panic_info| {
if let Some(location) = panic_info.location() {
println!(
"panic occurred in file '{}' at line {}",
location.file(),
location.line(),
);
} else {
println!("panic occurred but can't get location information...");
}
}));
panic_any(42);
}
````
Before:
`panic occurred in file '/rustc/ff2c947c00f867b9f012e28ba88cecfbe556f904/library/std/src/panic.rs' at line 59`
After:
`panic occurred in file 'src/main.rs' at line 17`
In particular the `is_dir`, `is_file` and `exists` functions says that querying a file requires querying the directory. On Windows this is not normally true.
Add inline attr to CString::into_inner so it can optimize out NonNull checks
It seems that currently if you convert any of the standard library's container to a pointer and then to a NonNull pointer, all will optimize out the NULL check except `CString`(https://godbolt.org/z/YPKW9G5xn),
because for some reason `CString::into_inner` isn't inlined even though it's a private function that should compile into a simple `mov` instruction.
Adding a simple `#[inline]` attribute solves this, code example:
```rust
use std::ffi::CString;
use std::ptr::NonNull;
pub fn cstring_nonull(mut n: CString) -> NonNull<i8> {
NonNull::new(CString::into_raw(n)).unwrap()
}
```
assembly before:
```asm
__ZN3wat14cstring_nonull17h371c755bcad76294E:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset %rbp, -16
movq %rsp, %rbp
.cfi_def_cfa_register %rbp
callq __ZN3std3ffi5c_str7CString10into_inner17h28ece07b276e2878E
testq %rax, %rax
je LBB0_2
popq %rbp
retq
LBB0_2:
leaq l___unnamed_1(%rip), %rdi
leaq l___unnamed_2(%rip), %rdx
movl $43, %esi
callq __ZN4core9panicking5panic17h92a83fa9085a8f73E
.cfi_endproc
.section __TEXT,__const
l___unnamed_1:
.ascii "called `Option::unwrap()` on a `None` value"
l___unnamed_3:
.ascii "wat.rs"
.section __DATA,__const
.p2align 3
l___unnamed_2:
.quad l___unnamed_3
.asciz "\006\000\000\000\000\000\000\000\006\000\000\000(\000\000"
```
Assembly after:
```asm
__ZN3wat14cstring_nonull17h9645eb9341fb25d7E:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset %rbp, -16
movq %rsp, %rbp
.cfi_def_cfa_register %rbp
movq %rdi, %rax
popq %rbp
retq
.cfi_endproc
```
(Related discussion on zulip: https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/NonNull.20From.3CBox.3CT.3E.3E)
doc: clarify Mutex::try_lock, etc. errors
Clarify error returns from Mutex::try_lock, RwLock::try_read,
RwLock::try_write to make it more obvious that both poisoning
and the lock being already locked are possible errors.
Bump bootstrap compiler to beta 1.53.0
This PR bumps the bootstrap compiler to version 1.53.0 beta, as part of our usual release process (this was supposed to be Wednesday's step, but creating the beta release took longer than expected).
The PR also includes the "Bootstrap: skip rustdoc fingerprint for building docs" commit, see the reasoning [on Zulip](https://zulip-archive.rust-lang.org/241545trelease/88450153betabootstrap.html).
r? `@Mark-Simulacrum`
Fix `vxworks`
Some PRs made the `vxworks` target not build anymore. This PR fixes that:
- #82973: copy `ExitStatusError` implementation from `unix`.
- #84716: no `libc::chroot` available on `vxworks`, so for now don't implement `os::unix::fs::chroot`.
add an example to explain std::io::Read::read returning 0 in some cases
I have always found the explanation about `Read::read` returning 0 to indicate EOF but not indefinitely, so here's more info using Linux as example. I can also add example code if necessary
MSVC: Avoid using jmp stubs for dll function imports
Windows import libraries contain two symbols for every function: `__imp_FunctionName` and `FunctionName` (where `FunctionName` is the name of the function to be imported).
`__imp_FunctionName` contains the address of the imported function. This will be filled in by the Windows executable loader at runtime. `FunctionName` contains a jmp stub that simply jumps to the address given by `__imp_FunctionName`. E.g. it's a function that solely contains a single jmp instruction:
```asm
jmp __imp_FunctionName
```
When using an external DLL function in Rust, by default the linker will link to FunctionName, causing a bit of indirection at runtime. In Microsoft's C++ it's possible to instead tell it to insert calls to the address in `__imp_FunctionName` by using the `__declspec(dllimport)` attribute. In Rust it's possible to get effectively the same behaviour using the `#[link]` attribute on `extern` blocks.
----
The second commit also merges multiple `extern` blocks into one block. This is because otherwise Rust will currently create duplicate linker arguments for each block. In this case having duplicates shouldn't matter much other than the noise when displaying the linker command.
Windows implementation of feature `path_try_exists`
Draft of a Windows implementation of `try_exists` (#83186).
The first commit reorganizes the code so I would be interested to get some feedback on if this is a good idea or not. It moves the `Path::try_exists` function to `fs::exists`. leaving the former as a wrapper for the latter. This makes it easier to provide platform specific implementations and matches the `fs::metadata` function.
The other commit implements a Windows specific variant of `exists`. I'm still figuring out my approach so this is very much a first draft. Eventually this will need some more eyes from knowledgable Windows people.
Clarify error returns from Mutex::try_lock, RwLock::try_read,
RwLock::try_write to make it more obvious that both poisoning
and the lock being already locked are possible errors.
std: Don't inline TLS accessor on MinGW
This is causing [issues] on Cargo's own CI for MinGW and given the
original investigation there's no reason that MinGW should work when
MSVC doesn't, this this tweaks the MSVC exception to being a Windows exception.
[issues]: https://github.com/rust-lang/cargo/runs/2626676503?check_suite_focus=true#step:9:2453
Move `std::memchr` to `sys_common`
`std::memchr` is a thin abstraction over the different `memchr` implementations in `sys`, along with documentation and tests. The module is only used internally by `std`, nothing is exported externally. Code like this is exactly what the `sys_common` module is for, so this PR moves it there.
Update list of allowed aarch64 features
I recently added these features to std_detect for aarch64 linux, pending [review](https://github.com/rust-lang/stdarch/pull/1146).
I have commented any features not supported by LLVM 9, the current minimum version for Rust. Some (PAuth at least) were renamed between 9 & 12 and I've left them disabled. TME, however, is not in LLVM 9 but I've left it enabled.
See https://github.com/rust-lang/stdarch/issues/993
Rollup of 8 pull requests
Successful merges:
- #84717 (impl FromStr for proc_macro::Literal)
- #85169 (Add method-toggle to <details> for methods)
- #85287 (Expose `Concurrent` (private type in public i'face))
- #85315 (adding time complexity for partition_in_place iter method)
- #85439 (Add diagnostic item to `CStr`)
- #85464 (Fix UB in documented example for `ptr::swap`)
- #85470 (Fix invalid CSS rules for a:hover)
- #85472 (CTFE Machine: do not expose Allocation)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Introduce `sys_common::rt::rtprintpanic!` to replace `sys_common::util` functionality
This PR introduces a new macro `rtprintpanic!`, similar to `sys_common::util::dumb_print` and uses that macro to replace all `sys_common::util` functionality.
std: Attempt again to inline thread-local-init across crates
Issue #25088 has been part of `thread_local!` for quite some time now.
Historical attempts have been made to add `#[inline]` to `__getit`
in #43931, #50252, and #59720, but these attempts ended up not landing
at the time due to segfaults on Windows.
In the interim though with `const`-initialized thread locals AFAIK this
is the only remaining bug which is why you might want to use
`#[thread_local]` over `thread_local!`. As a result I figured it was
time to resubmit this and see how it fares on CI and if I can help
debugging any issues that crop up.
Closes#25088
Override `clone_from` for some types
Override `clone_from` method of the `Clone` trait for:
- `cell::RefCell`
- `cmp::Reverse`
- `io::Cursor`
- `mem::ManuallyDrop`
This can bring performance improvements.
Issue #25088 has been part of `thread_local!` for quite some time now.
Historical attempts have been made to add `#[inline]` to `__getit`
in #43931, #50252, and #59720, but these attempts ended up not landing
at the time due to segfaults on Windows.
In the interim though with `const`-initialized thread locals AFAIK this
is the only remaining bug which is why you might want to use
`#[thread_local]` over `thread_local!`. As a result I figured it was
time to resubmit this and see how it fares on CI and if I can help
debugging any issues that crop up.
Closes#25088
Provide ExitStatusError
Closes#73125
In MR #81452 "Add #[must_use] to [...] process::ExitStatus" we concluded that the existing arrangements in are too awkward so adding that `#[must_use]` is blocked on improving the ergonomics.
I wrote a mini-RFC-style discusion of the approach in https://github.com/rust-lang/rust/issues/73125#issuecomment-771092741
# Stabilization report
## Summary
This stabilizes using macro expansion in key-value attributes, like so:
```rust
#[doc = include_str!("my_doc.md")]
struct S;
#[path = concat!(env!("OUT_DIR"), "/generated.rs")]
mod m;
```
See the changes to the reference for details on what macros are allowed;
see Petrochenkov's excellent blog post [on internals](https://internals.rust-lang.org/t/macro-expansion-points-in-attributes/11455)
for alternatives that were considered and rejected ("why accept no more
and no less?")
This has been available on nightly since 1.50 with no major issues.
## Notes
### Accepted syntax
The parser accepts arbitrary Rust expressions in this position, but any expression other than a macro invocation will ultimately lead to an error because it is not expected by the built-in expression forms (e.g., `#[doc]`). Note that decorators and the like may be able to observe other expression forms.
### Expansion ordering
Expansion of macro expressions in "inert" attributes occurs after decorators have executed, analogously to macro expressions appearing in the function body or other parts of decorator input.
There is currently no way for decorators to accept macros in key-value position if macro expansion must be performed before the decorator executes (if the macro can simply be copied into the output for later expansion, that can work).
## Test cases
- https://github.com/rust-lang/rust/blob/master/src/test/ui/attributes/key-value-expansion-on-mac.rs
- https://github.com/rust-lang/rust/blob/master/src/test/rustdoc/external-doc.rs
The feature has also been dogfooded extensively in the compiler and
standard library:
- https://github.com/rust-lang/rust/pull/83329
- https://github.com/rust-lang/rust/pull/83230
- https://github.com/rust-lang/rust/pull/82641
- https://github.com/rust-lang/rust/pull/80534
## Implementation history
- Initial proposal: https://github.com/rust-lang/rust/issues/55414#issuecomment-554005412
- Experiment to see how much code it would break: https://github.com/rust-lang/rust/pull/67121
- Preliminary work to restrict expansion that would conflict with this
feature: https://github.com/rust-lang/rust/pull/77271
- Initial implementation: https://github.com/rust-lang/rust/pull/78837
- Fix for an ICE: https://github.com/rust-lang/rust/pull/80563
## Unresolved Questions
~~https://github.com/rust-lang/rust/pull/83366#issuecomment-805180738 listed some concerns, but they have been resolved as of this final report.~~
## Additional Information
There are two workarounds that have a similar effect for `#[doc]`
attributes on nightly. One is to emulate this behavior by using a limited version of this feature that was stabilized for historical reasons:
```rust
macro_rules! forward_inner_docs {
($e:expr => $i:item) => {
#[doc = $e]
$i
};
}
forward_inner_docs!(include_str!("lib.rs") => struct S {});
```
This also works for other attributes (like `#[path = concat!(...)]`).
The other is to use `doc(include)`:
```rust
#![feature(external_doc)]
#[doc(include = "lib.rs")]
struct S {}
```
The first works, but is non-trivial for people to discover, and
difficult to read and maintain. The second is a strange special-case for
a particular use of the macro. This generalizes it to work for any use
case, not just including files.
I plan to remove `doc(include)` when this is stabilized. The
`forward_inner_docs` workaround will still compile without warnings, but
I expect it to be used less once it's no longer necessary.
Simplify `cfg(any(unix, target_os="redox"))` in example to just `cfg(unix)`
Update example for `OsString` that handled `redox` seperately from `unix`: Redox has been completely integrated under `target_family="unix"`, so `cfg(unix)` implies `target_os="redox"`
35dbef2350/compiler/rustc_target/src/spec/redox_base.rs (L26)
Expand WASI abbreviation in docs
I was pretty sure this was related to something for WebAssembly but wasn't 100% sure so I checked but even on these top-level docs I couldn't find the abbreviation expanded. I'm normally used to Rust docs being detailed and explanatory and writing abbreviations like this out in full at least once so I thought it was worth the change. Feel free to close this if it's too much.
Do not allocate or unwind after fork
### Objective scenarios
* Make (simple) panics safe in `Command::pre_exec_hook`, including most `panic!` calls, `Option::unwrap`, and array bounds check failures.
* Make it possible to `libc::fork` and then safely panic in the child (needed for the above, but this requirement means exposing the new raw hook API which the `Command` implementation needs).
* In singlethreaded programs, where panic in `pre_exec_hook` is already memory-safe, prevent the double-unwinding malfunction #79740.
I think we want to make panic after fork safe even though the post-fork child environment is only experienced by users of `unsafe`, beause the subset of Rust in which any panic is UB is really far too hazardous and unnatural.
#### Approach
* Provide a way for a program to, at runtime, switch to having panics abort. This makes it possible to panic without making *any* heap allocations, which is needed because on some platforms malloc is UB in a child forked from a multithreaded program (see https://github.com/rust-lang/rust/pull/80263#issuecomment-774272370, and maybe also the SuS [spec](https://pubs.opengroup.org/onlinepubs/9699919799/functions/fork.html)).
* Make that change in the child spawned by `Command`.
* Document the rules comprehensively enough that a programmer has a fighting chance of writing correct code.
* Test that this all works as expected (and in particular, that there aren't any heap allocations we missed)
Fixes#79740
#### Rejected (or previously attempted) approaches
* Change the panic machinery to be able to unwind without allocating, at least when the payload and message are both `'static`. This seems like it would be even more subtle. Also that is a potentially-hot path which I don't want to mess with.
* Change the existing panic hook mechanism to not convert the message to a `String` before calling the hook. This would be a surprising change for existing code and would not be detected by the type system.
* Provide a `raw_panic_hook` function to intercept panics in a way that doesn't allocate. (That was an earlier version of this MR.)
### History
This MR could be considered a v2 of #80263. Thanks to everyone who commented there. In particular, thanks to `@m-ou-se,` `@Mark-Simulacrum` and `@hyd-dev.` (Tagging you since I think you might be interested in this new MR.) Compared to #80263, this MR has very substantial changes and additions.
Additionally, I have recently (2021-04-20) completely revised this series following very helpful comments from `@m-ou-se.`
r? `@m-ou-se`
Some platforma (eg ARM64) apparently generate SIGTRAP for panic abort!
See eg
https://github.com/rust-lang/rust/pull/81858#issuecomment-840702765
This is probably a bug, but we don't want to entangle this MR with it.
When it's fixed, this commit should be reverted.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Add auto traits and clone trait migrations for RFC2229
This PR
- renames the existent RFC2229 migration `disjoint_capture_drop_reorder` to `disjoint_capture_migration`
- add additional migrations for auto traits and clone trait
Closesrust-lang/project-rfc-2229#29Closesrust-lang/project-rfc-2229#28
r? `@nikomatsakis`
It is unergnomic to have to say things like
bad.into_status().signal()
Implementing `ExitStatusExt` for `ExitStatusError` fixes this.
Unfortunately it does mean making a previously-infallible method
capable of panicing, although of course the existing impl remains
infallible.
The alternative would be a whole new `ExitStatusErrorExt` trait.
`<ExitStatus as ExitStatusExt>::into_raw()` is not particularly
ergonomic to call because of the often-required type annotation.
See for example the code in the test case in
library/std/src/sys/unix/process/process_unix/tests.rs
Perhaps we should provide equivalent free functions for `ExitStatus`
and `ExitStatusExt` in std::os::unix::process and maybe deprecate this
trait method. But I think that is for the future.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Closes#73125
This is in pursuance of
Issue #73127 Consider adding #[must_use] to std::process::ExitStatus
In
MR #81452 Add #[must_use] to [...] process::ExitStatus
we concluded that the existing arrangements in are too awkward
so adding that #[must_use] is blocked on improving the ergonomics.
I wrote a mini-RFC-style discusion of the approach in
https://github.com/rust-lang/rust/issues/73125#issuecomment-771092741
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Change param name (k to key and v to value) in std::env module
1. When I was reading code the ide displayed `k` and `v`, so I
thought it would be better to show key and value?
2. I noticed var method already uses `key` instead of `k` so it
is more consistent to use `key` instead of `k`?
Thanks
Emit errors/warns on some wrong uses of rustdoc attributes
This PR adds a few diagnostics:
- error if conflicting `#[doc(inline)]`/`#[doc(no_inline)]` are found
- introduce the `invalid_doc_attributes` lint (warn-by-default) which triggers:
- if a crate-level attribute is used on a non-`crate` item
- if `#[doc(inline)]`/`#[doc(no_inline)]` is used on a non-`use` item
The code could probably be improved but I wanted to get feedback first. Also, some of those changes could be considered breaking changes, so I don't know what the procedure would be? ~~And finally, for the warnings, they are currently hard warnings, maybe it would be better to introduce a lint?~~ (EDIT: introduced the `invalid_doc_attributes` lint)
Closes#80275.
r? `@jyn514`
fork fails there. The failure message is confusing: so c.status()
returns an Err, the closure panics, and the test thinks the panic was
propagated from inside the child.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Rearrange SGX split module files
In #75979 several inlined modules were split out into multiple files.
This PR keeps the multiple files but moves a few things around to
organize things in a coherent way.
Cleanup of `wasm`
Some more cleanup of `sys`, this time `wasm`
- Reuse `unsupported::args` (functionally equivalent implementation, just an empty iterator).
- Split out `atomics` implementation of `wasm::thread`, the non-`atomics` implementation is reused from `unsupported`.
- Move all of the `atomics` code to a separate directory `wasm/atomics`.
````@rustbot```` label: +T-libs-impl
r? ````@m-ou-se````
In #75979 several inlined modules were split out into multiple files.
This PR keeps the multiple files but moves a few things around to
organize things in a coherent way.
This tests that we can indeed safely panic after fork, both
a raw libc::fork and in a Command pre_exec hook.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
This is safe (does not involve heap allocation) but we don't yet have
a test to ensure that stays true. That will come in a moment.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Unwinding after fork() in the child is UB on some platforms, because
on those (including musl) malloc can be UB in the child of a
multithreaded program, and unwinding must box for the payload.
Even if it's safe, unwinding past fork() in the child causes whatever
traps the unwind to return twice. This is very strange and clearly
not desirable. With the default behaviour of the thread library, this
can even result in a panic in the child being transformed into zero
exit status (ie, success) as seen in the parent!
Fixes#79740.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
We must change the atomic read on panic entry to `Acquire`, to pick up
a possible an `always_panic` on another thread.
We add `count` to the names of panic_count::get and ::is_zaero,
because now there is another reason why panic ought to maybe abort.
Renaming these ensures that we have checked every call site to ensure
that they don't need further adjustment.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Stablize {HashMap,BTreeMap}::into_{keys,values}
I would propose to stabilize `{HashMap,BTreeMap}::into_{keys,values}`( aka. `map_into_keys_values`).
Closes#75294.
Rollup of 11 pull requests
Successful merges:
- #83553 (Update `ptr` docs with regards to `ptr::addr_of!`)
- #84183 (Update RELEASES.md for 1.52.0)
- #84709 (Add doc alias for `chdir` to `std::env::set_current_dir`)
- #84803 (Reduce duplication in `impl_dep_tracking_hash` macros)
- #84808 (Account for unsatisfied bounds in E0599)
- #84843 (use else if in std library )
- #84865 (rustbuild: Pass a `threads` flag that works to windows-gnu lld)
- #84878 (Clarify documentation for `[T]::contains`)
- #84882 (platform-support: Center the contents of the `std` and `host` columns)
- #84903 (Remove `rustc_middle::mir::interpret::CheckInAllocMsg::NullPointerTest`)
- #84913 (Do not ICE on invalid const param)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Add doc alias for `chdir` to `std::env::set_current_dir`
Searching for `chdir` in the Rust documentation produces no useful
results.
I wrote some code recently that called `libc::chdir` and manually
handled errors, because I didn't realize that the safe
`std::env::set_current_dir` existed. I searched for `chdir` and
`change_dir` and `change_directory` (the latter two based on the
precedent of unabbreviating set by `create_dir`), and I also read
through `std::fs` expecting to potentially find it there. Given that
none of those led to `std::env::set_current_dir`, I think that provides
sufficient justification to add this specific alias.
Update `ptr` docs with regards to `ptr::addr_of!`
This updates the documentation since `ptr::addr_of!` and `ptr::addr_of_mut!` are now stable. One might remove the distinction between the sections `# On packed structs` and `# Examples`, as the old section on packed structs was primarily to prevent users of doing undefined behavior, which is not necessary anymore.
Technically there is now wrong/outdated documentation on stable, but I don't think this is worth a point release 😉Fixes#83509.
``````````@rustbot`````````` modify labels: T-doc
Move all `sys::ext` modules to `os`
This PR moves all `sys::ext` modules to `os`, centralizing the location of all `os` code and simplifying the dependencies between `os` and `sys`.
Because this also removes all uses `cfg_if!` on publicly exported items, where after #81969 there were still a few left, this should properly work around https://github.com/rust-analyzer/rust-analyzer/issues/6038.
`@rustbot` label: +T-libs-impl
This updates the documentation since `ptr::addr_of!` and
`ptr::addr_of_mut!` are now stable. One might remove the distinction
between the sections `# On packed structs` and `# Examples`, as the old
section on packed structs was primarily to prevent users of doing unde-
fined behavior, which is not necessary anymore.
There is also a new section in "how to obtain a pointer", which referen-
ces the `ptr::addr_of!` macros.
This commit contains squashed commits from code review.
Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Co-authored-by: Soveu <marx.tomasz@gmail.com>
Co-authored-by: Ralf Jung <post@ralfj.de>
Replace 'NULL' with 'null'
This replaces occurrences of "NULL" with "null" in docs, comments, and compiler error/lint messages. This is for the sake of consistency, as the lowercase "null" is already the dominant form in Rust. The all-caps NULL looks like the C macro (or SQL keyword), which seems out of place in a Rust context, given that NULL does not exist in the Rust language or standard library (instead having [`ptr::null()`](https://doc.rust-lang.org/stable/std/ptr/fn.null.html)).
Be stricter about rejecting LLVM reserved registers in asm!
LLVM will silently produce incorrect code if these registers are used as operands.
cc `@rust-lang/wg-inline-asm`
Add std::os::unix::fs::chroot to change the root directory of the current process
This is a straightforward wrapper that uses the existing helpers for C
string handling and errno handling.
Having this available is convenient for UNIX utility programs written in
Rust, and avoids having to call the unsafe `libc::chroot` directly and
handle errors manually, in a program that may otherwise be entirely safe
code.
Reuse `sys::unix::cmath` on other platforms
Reuse `sys::unix::cmath` on all non-`windows` platforms.
`unix` is chosen as the canonical location instead of `unsupported` or `common` because `unsupported` doesn't make sense semantically and `common` is reserved for code that is supported on all platforms. Also `unix` is already the home of some non-`windows` code that is technically not exclusive to `unix` like `unix::path`.
This is a straightforward wrapper that uses the existing helpers for C
string handling and errno handling.
Having this available is convenient for UNIX utility programs written in
Rust, and avoids having to call the unsafe `libc::chroot` directly and
handle errors manually, in a program that may otherwise be entirely safe
code.
Link between std::env::{var, var_os} and std::env::{vars, vars_os}
In #84551 I linked between `std::env::{args, args_os}` and this PR does the same but for `std::env::{var, var_os}` and `std::env::{vars, vars_os}`. Now all of `std::env::{var, var_os, vars, vars_os, args, args_os}` should each mention their `_os` or non-`_os` equivalent in the docs so that you can easily navigate between them.
Point out that behavior might be switched on 2015 and 2018 too one day
Reword documentation to make it clear that behaviour can be switched on older editions too, one day in the future. It doesn't *have* to be switched, but I think it's good to have it as an option and re-evaluate it a few months/years down the line when e.g. the crates that showed up in crater were broken by different changes in the language already.
cc #25725, #65819, #66145, #84147 , and https://github.com/rust-lang/rust/issues/84133#issuecomment-818005314
Remove `DropGuard` in `sys::windows::process` and use `StaticMutex` instead
`StaticMutex` is a mutex that when locked provides a guard that unlocks the mutex again when dropped, thus provides the exact same functionality as `DropGuard`. `StaticMutex` is used in more places, and is thus preferred over an ad-hoc construct like `DropGuard`.
````@rustbot```` label: +T-libs-impl
Simplify `Mutex::into_inner`
Thanks to #77147, `Mutex` do not implement `Drop` directly, so the old unsafe implementation of `into_inner` is not relevant anymore.
Reuse modules on `hermit`
Reuse the following modules on `hermit`:
- `unix::path` (contents identical)
- `unsupported::io` (contents identical)
- `unsupported::thread_local_key` (contents functionally identical, only changes are the panic error messages)
`@rustbot` label: +T-libs-impl
Unify the docs of std::env::{args_os, args} more
I noticed that `args_os` was missing some information and I thought it should mention `args` for when you want more safety just like how `args` mentions `args_os` if you don't want it to panic on invalid Unicode.
Inline most raw socket, fd and handle conversions
Now that file descriptor types on Unix have niches, it is advantageous for user libraries which provide file descriptor wrappers (e.g. `Socket` from socket2) to store a `File` internally instead of a `RawFd`, so that the niche can be taken advantage of. However, doing so will currently result in worse performance as `IntoRawFd`, `FromRawFd` and `AsRawFd` are not inlined. This change adds `#[inline]` to those methods on std types that wrap file descriptors, handles or sockets.
move core::hint::black_box under its own feature gate
The `black_box` function had its own RFC and is tracked separately from the `test` feature at https://github.com/rust-lang/rust/issues/64102. Let's reflect this in the feature gate.
To avoid breaking all the benchmarks, libtest's `test::black_box` is a wrapping definition, not a reexport -- this means it is still under the `test` feature gate.
Cautiously add IntoIterator for arrays by value
Add the attribute described in #84133, `#[rustc_skip_array_during_method_dispatch]`, which effectively hides a trait from method dispatch when the receiver type is an array.
Then cherry-pick `IntoIterator for [T; N]` from #65819 and gate it with that attribute. Arrays can now be used as `IntoIterator` normally, but `array.into_iter()` has edition-dependent behavior, returning `slice::Iter` for 2015 and 2018 editions, or `array::IntoIter` for 2021 and later.
r? `@nikomatsakis`
cc `@LukasKalbertodt` `@rust-lang/libs`
Rework `init` and `cleanup`
This PR reworks the code in `std` that runs before and after `main` and centralizes this code respectively in the functions `init` and `cleanup` in both `sys_common` and `sys`. This makes is easy to see what code is executed during initialization and cleanup on each platform just by looking at e.g. `sys::windows::init`.
Full list of changes:
- new module `rt` in `sys_common` to contain `init` and `cleanup` and the runtime macros.
- `at_exit` and the mechanism to register exit handlers has been completely removed. In practice this was only used for closing sockets on windows and flushing stdout, which have been moved to `cleanup`.
- <s>On windows `alloc` and `net` initialization is now done in `init`, this saves a runtime check in every allocation and network use.</s>
Explicitly implement `!Send` and `!Sync` for `sys::{Args, Env}`
Remove the field `_dont_send_or_sync_me: PhantomData<*mut ()>` in favor of an explicit implementation of `!Send` and `!Sync`.
Move `sys_common::poison` to `sync::poison`
`sys_common` should not contain publicly exported types, only platform-independent abstractions on top of `sys`, which `sys_common::poison` is not. There is thus no reason for the module to not live under `sync`.
Part of #84187.
Remove `sys::args::Args::inner_debug` and use `Debug` instead
This removes the method `sys::args::Args::inner_debug` on all platforms and implements `Debug` for `Args` instead.
I believe this creates a more natural API for the different platforms under `sys`: export a type `Args: Debug + Iterator + ...` vs. `Args: Iterator + ...` and with a method `inner_debug`.
Move `sys_common::rwlock::StaticRWLock` etc. to `sys::unix::rwlock`
This moves `sys_common::rwlock::StaticRwLock`, `RWLockReadGuard` and `RWLockWriteGuard` to `sys::unix::rwlock`. They are already `#[cfg(unix)]` and don't need to be in `sys_common`.
Replace `Void` in `sys` with never type
This PR replaces several occurrences in `sys` of the type `enum Void {}` with the Rust never type (`!`).
The name `Void` is unfortunate because in other languages (C etc.) it refers to a unit type, not an uninhabited type.
Note that the previous stabilization of the never type was reverted, however all uses here are implementation details and not publicly visible.
Move `sys::vxworks` code to `sys::unix`
Follow-up to #77666, `sys::vxworks` is almost identical to `sys::unix`, the only differences are the `rand`, `thread_local_dtor`, and `process` implementation. Since `vxworks` is `target_family = unix` anyway, there is no reason for the code not to live inside of `sys::unix` like all the other unix-OSes.
e41f378f82/compiler/rustc_target/src/spec/vxworks_base.rs (L12)
``@rustbot`` label: +T-libs-impl
Replace all `fmt.pad` with `debug_struct`
This replaces any occurrence of:
- `f.pad("X")` with `f.debug_struct("X").finish()`
- `f.pad("X { .. }")` with `f.debug_struct("X").finish_non_exhaustive()`
This is in line with existing formatting code such as
1255053067/library/std/src/sync/mpsc/mod.rs (L1470-L1475)
Add `Unsupported` to `std::io::ErrorKind`
I noticed a significant portion of the uses of `ErrorKind::Other` in std is for unsupported operations.
The notion that a specific operation is not available on a target (and will thus never succeed) seems semantically distinct enough from just "an unspecified error occurred", which is why I am proposing to add the variant `Unsupported` to `std::io::ErrorKind`.
**Implementation**:
The following variant will be added to `std::io::ErrorKind`:
```rust
/// This operation is unsupported on this platform.
Unsupported
```
`std::io::ErrorKind::Unsupported` is an error returned when a given operation is not supported on a platform, and will thus never succeed; there is no way for the software to recover. It will be used instead of `Other` where appropriate, e.g. on wasm for file and network operations.
`decode_error_kind` will be updated to decode operating system errors to `Unsupported`:
- Unix and VxWorks: `libc::ENOSYS`
- Windows: `c::ERROR_CALL_NOT_IMPLEMENTED`
- WASI: `wasi::ERRNO_NOSYS`
**Stability**:
This changes the kind of error returned by some functions on some platforms, which I think is not covered by the stability guarantees of the std? User code could depend on this behavior, expecting `ErrorKind::Other`, however the docs already mention:
> Errors that are `Other` now may move to a different or a new `ErrorKind` variant in the future. It is not recommended to match an error against `Other` and to expect any additional characteristics, e.g., a specific `Error::raw_os_error` return value.
The most recent variant added to `ErrorKind` was `UnexpectedEof` in `1.6.0` (almost 5 years ago), but `ErrorKind` is marked as `#[non_exhaustive]` and the docs warn about exhaustively matching on it, so adding a new variant per se should not be a breaking change.
The variant `Unsupported` itself could be marked as `#[unstable]`, however, because this PR also immediately uses this new variant and changes the errors returned by functions I'm inclined to agree with the others in this thread that the variant should be insta-stabilized.
Deprecate the core::raw / std::raw module
It only contains the `TraitObject` struct which exposes components of wide pointer. Pointer metadata APIs are designed to replace this: https://github.com/rust-lang/rust/issues/81513
This commit adds a variant of the `thread_local!` macro as a new
`thread_local_const_init!` macro which requires that the initialization
expression is constant (e.g. could be stuck into a `const` if so
desired). This form of thread local allows for a more efficient
implementation of `LocalKey::with` both if the value has a destructor
and if it doesn't. If the value doesn't have a destructor then `with`
should desugar to exactly as-if you use `#[thread_local]` given
sufficient inlining.
The purpose of this new form of thread locals is to precisely be
equivalent to `#[thread_local]` on platforms where possible for values
which fit the bill (those without destructors). This should help close
the gap in performance between `thread_local!`, which is safe, relative
to `#[thread_local]`, which is not easy to use in a portable fashion.
Fix join_paths error display.
On unix, the error from `join_paths` looked like this:
```
path segment contains separator `58`
```
This PR changes it to look like this:
```
path segment contains separator `:`
```
Move `std::sys_common::alloc` to new module `std::sys::common`
6b56603e35/library/std/src/sys_common/mod.rs (L7-L13)
It was my impression that the goal for `std::sys` has changed from extracting it into a separate crate to making std work with features. However the fact remains that there is a lot of interdependence between `sys` and `sys_common`, this is because `sys_common` contains two types of code:
- abstractions over the different platform implementations in `std::sys` (for example [`std::sys_common::mutex`](https://github.com/rust-lang/rust/blob/master/library/std/src/sys_common/mutex.rs))
- code shared between platforms (for example [`std::sys_common::alloc`](https://github.com/rust-lang/rust/blob/master/library/std/src/sys_common/alloc.rs))
This PR attempts to address this by adding a new module `common` to `std::sys` which will contain code shared between platforms, `alloc.rs` in this case but more can be moved over in the future.
Optimize for the common case where the input write size is less than the
buffer size. This slightly increases the cost for pathological write
patterns that commonly fill the buffer exactly, but if a client is doing
that frequently, they're already paying the cost of frequent flushing,
etc., so the cost is of this optimization to them is relatively small.
We use a Vec as our internal, constant-sized buffer, but the overhead of
using methods like `extend_from_slice` can be enormous, likely because
they don't get inlined, because `Vec` has to repeat bounds checks that
we've already done, and because it makes considerations for things like
reallocating, even though they should never happen.
Ensure that `write` and `write_all` can be inlined and that their
commonly executed fast paths can be as short as possible.
`write_vectored` would likely benefit from the same optimization, but I
omitted it because its implementation is more complex, and I don't have
a benchmark on hand to guide its optimization.
Stabilize `bufreader_seek_relative`
This PR marks `BufReader::seek_relative` as stable - the associated issue, #31100, has passed the final comment period without any issues, and from what I understand, the only thing left to stabilize this is to submit a PR marking the method as stable.
Closes#31100.
Turn old edition lint (anonymous-parameters) into warn-by-default on 2015
This makes `anonymous_parameters` <s>and `keyword_idents` </s>warn-by-default on the 2015 edition. I would also like to do this for `absolute_paths_not_starting_with_crate`, but I feel that case is slightly less clear-cut.
Note that this only affects code on the 2015 edition, such code is illegal in future editions anyway.
This was spurred by https://github.com/dtolnay/syn/issues/972: old edition syntax breaks tooling (like syn), and while the tooling should be free to find its balance on how much to support prior editions, it does seem like we should be nudging such code towards the newer edition, and we can do that by turning this Allow lint into a Warn.
In general, I feel like migration lints from an old edition should be made Warn after a year or so, and idiom lints for the new edition should be made Warn after a couple months.
cc `@m-ou-se,` this is for stuff from the 2015-2018 migration but you might be interested.
Update stdarch submodule (to before it switched to const generics)
https://github.com/rust-lang/rust/pull/83278#issuecomment-812389823: This unblocks #82539.
Major changes:
- More AVX-512 intrinsics.
- More ARM & AArch64 NEON intrinsics.
- Updated unstable WASM intrinsics to latest draft standards.
- std_detect is now a separate crate instead of a submodule of std.
I double-checked and the first use of const generics looks like 8d5017861e, which isn't included in this PR.
r? `@Amanieu`
This also includes a cherry-pick of
ec1461905b
and https://github.com/rust-lang/stdarch/pull/1108 to fix a build
failure.
It also adds a re-export of various macros to the crate root of libstd -
previously they would show up automatically because std_detect was defined
in the same crate.
clean up example on read_to_string
This is the same thing, but simpler.
This came out of a comment from a user: https://news.ycombinator.com/item?id=25318117 but rather than hide the signature of main, I think a `use` plus not including the `'static` makes more sense.
