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.
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.
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
Convert instances of `target_os = "macos"` to `target_vendor = "apple"`
https://github.com/rust-lang/rust/pull/124491 migrated towards using `target_vendor = "apple"` more, as there's very little difference between iOS, tvOS, watchOS and visionOS. In that PR, I only did the changes where the standard library already had fixes for iOS, that I could confidently apply to the other targets.
However, there's actually also not that big of a gap between macOS and the aforementioned platforms - so in this PR, I've gone through a few of the instances of `target_os = "macos"` and replaced it with `target_vendor = "apple"` to improve support on those platforms, see the commits for details.
r? workingjubilee
CC `@thomcc` `@simlay` (do tell me if I should stop pinging you on these Apple PRs)
`@rustbot` label O-apple
This uses `libc::fcntl`, which, while not explicitly marked as available
in the headers, is already used by `File::sync_all` and `File::sync_data`
on these platforms, so should be fine to use here as well.
Tested in the iOS simulator with something like:
```
let mut buf = vec![0; c_int::MAX as usize - 1 + 2];
let read_bytes = f.read(&mut buf).unwrap();
```
The code is written in a way to support 32-bit iOS and tvOS ARM devices,
for future compatibility even though we currently only have a target for
32-bit iOS ARM.
library/std: Fix build for NetBSD targets with 32-bit `c_long`
This fixes building `std` for targets like `mipsel-unknown-netbsd`.
If `c_long` is an `i64`, this conversion works with `Into`. But if it's an `i32`, this failed to convert a `u32` to an `i32`.
