Clarify example in `Pin::new_unchecked` docs
This example in the docs of `Pin::new_unchecked` puzzled me for a relatively long time. Now I understand that it comes down to the difference between dropping the `Pin` vs dropping the pinned value.
I have extended the explanation to highlight this difference. In my opinion it is clearer now, and I hope it helps others understand `Pin` better.
fix OS-specific I/O safety docs since the io_safety feature is stable
Looks like this text was forgotten to be updated when `io_safety` got stabilized: it still says "once the io_safety feature is stable".
Also adjust the wording a bit for how these docs relate to the general concept of I/O safety.
Add Minimal Std implementation for UEFI
# Implemented modules:
1. alloc
2. os_str
3. env
4. math
# Related Links
Tracking Issue: https://github.com/rust-lang/rust/issues/100499
API Change Proposal: https://github.com/rust-lang/libs-team/issues/87
# Additional Information
This was originally part of https://github.com/rust-lang/rust/pull/100316. Since that PR was becoming too unwieldy and cluttered, and with suggestion from `@dvdhrm,` I have extracted a minimal std implementation to this PR.
The example in `src/doc/rustc/src/platform-support/unknown-uefi.md` has been tested for `x86_64-unknown-uefi` and `i686-unknown-uefi` in OVMF. It would be great if someone more familiar with AARCH64 can help with testing for that target.
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
Document panics on unsigned wrapping_div/rem calls (#116063)
Add missing `# Panics` sections to the `uint_impl!` macro, documenting that the `wrapping_rem/div` calls will panic if passed zero.
Add the `cfg_match!` macro
# Movitation
Adds a match-like version of the `cfg_if` crate without a RFC [for the same reasons that caused `matches!` to be included in the standard library](https://github.com/rust-lang/rust/pull/65479).
* General-purpose (not domain-specific)
* Simple (the implementation is short) and useful (things can become difficult with several `cfg`s)
* Very popular [on crates.io ](https://crates.io/crates/cfg-if) (currently 3th in all-time downloads)
* The two previous points combined make it number three in [left-pad index](https://twitter.com/bascule/status/1184523027888988160) score
```rust
match_cfg! {
cfg(unix) => {
fn foo() { /* unix specific functionality */ }
}
cfg(target_pointer_width = "32") => {
fn foo() { /* non-unix, 32-bit functionality */ }
}
_ => {
fn foo() { /* fallback implementation */ }
}
}
```
# Considerations
A match-like syntax feels more natural in the sense that each macro fragment resembles an arm but I personally don't mind switching to any other desired syntax.
The lack of `#[ ... ]` is intended to reduce typing, nevertheless, the same reasoning described above can also be applied to this aspect.
Since blocks are intended to only contain items, anything but `cfg` is not expected to be supported at the current or future time.
~~Credits goes to `@gnzlbg` because most of the code was shamelessly copied from https://github.com/gnzlbg/match_cfg.~~
Credits goes to `@alexcrichton` because most of the code was shamelessly copied from https://github.com/rust-lang/cfg-if.
Raise minimum supported Apple OS versions
This implements the proposal to raise the minimum supported Apple OS versions as laid out in the now-completed MCP (https://github.com/rust-lang/compiler-team/issues/556).
As of this PR, rustc and the stdlib now support these versions as the baseline:
- macOS: 10.12 Sierra
- iOS: 10
- tvOS: 10
- watchOS: 5 (Unchanged)
In addition to everything this breaks indirectly, these changes also erase the `armv7-apple-ios` target (currently tier 3) because the oldest supported iOS device now uses ARMv7s. Not sure what the policy around tier3 target removal is but shimming it is not an option due to the linker refusing.
[Per comment](https://github.com/rust-lang/compiler-team/issues/556#issuecomment-1297175073), this requires a FCP to merge. cc `@wesleywiser.`
without this, the only way to create a `LitKind::Byte` is by
doing `"b'a'".parse::<Literal>()`, this solves that by enabling
`Literal::byte_character(b'a')`
- Some comment fixes.
- Make some functions unsafe.
- Make helpers module private.
- Rebase on master
- Update r-efi to v4.2.0
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
- Make BootServices unavailable if ExitBootServices event is signaled.
- Use thread locals for SystemTable and ImageHandle
Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>
Command: also print removed env vars
There is no real shell syntax for unsetting an env var so easily, so we have to make one up. But we already do that for showing the 'program' name so I hope that's okay here, too. No strong opinion on what that should look like, I went with `unset(VAR_NAME)` for now.
Call panic_display directly in const_panic_fmt.
`panic_str` just directly calls `panic_display`. The only reason `panic_str` exists, is for a lint to detect an expansion of `panic_2015!(expr)` (which expands to `panic_str`).
It is `panic_display` that is hooked by const-eval, which is the reason we call it here.
Part of https://github.com/rust-lang/rust/issues/116005
r? ``@oli-obk``
Rename BoxMeUp to PanicPayload.
"BoxMeUp" is not very clear. Let's rename that to a description of what it actually represents: a panic payload.
This PR also renames the structs that implement this trait to have more descriptive names.
Part of https://github.com/rust-lang/rust/issues/116005
r? `@oli-obk`
Simplify/Optimize FileEncoder
FileEncoder is basically a BufWriter except that it exposes access to the not-written-to-yet region of the buffer so that some users can write directly to the buffer. This strategy is awesome because it lets us avoid calling memcpy for small copies, but the previous strategy was based on the writer accessing a `&mut [MaybeUninit<u8>; N]` and returning a `&[u8]` which is an API which currently mandates the use of unsafe code, making that interface in general not that appealing.
So this PR cleans up the FileEncoder implementation and builds on that general idea of direct buffer access in order to prevent `memcpy` calls in a few key places when encoding the dep graph and rmeta tables. The interface used here is now 100% safe, but with the caveat that internally we need to avoid trusting the number of bytes that the provided function claims to have written.
The original primary objective of this PR was to clean up the FileEncoder implementation so that the fix for the following issues would be easy to implement. The fix for these issues is to correctly update self.buffered even when writes fail, which I think it's easy to verify manually is now done, because all the FileEncoder methods are small.
Fixes https://github.com/rust-lang/rust/issues/115298
Fixes https://github.com/rust-lang/rust/issues/114671
Fixes https://github.com/rust-lang/rust/issues/114045
Fixes https://github.com/rust-lang/rust/issues/108100
Fixes https://github.com/rust-lang/rust/issues/106787
Refactor `thread_info` to remove the `RefCell`
`thread_info` currently uses `RefCell`-based initialization. Refactor this to use `OnceCell` instead which is more performant and better suits the needs of one-time initialization.
This is nobody's bottleneck but OnceCell checks are a single `cmp` vs. `RefCell<Option>` needing runtime logic
Don't modify libstd to dump rustc ICEs
Do a much simpler thing and just dump a `std::backtrace::Backtrace` to file.
r? `@estebank` `@oli-obk`
Fixes#115610
Add initial libstd support for Xous
This patchset adds some minimal support to the tier-3 target `riscv32imac-unknown-xous-elf`. The following features are supported:
* alloc
* thread creation and joining
* thread sleeping
* thread_local
* panic_abort
* mutex
* condvar
* stdout
Additionally, internal support for the various Xous primitives surrounding IPC have been added as part of the Xous FFI. These may be exposed as part of `std::os::xous::ffi` in the future, however for now they are not public.
This represents the minimum viable product. A future patchset will add support for networking and filesystem support.
