All #[cfg(unix)] platforms follow the POSIX standard and define _SC_IOV_MAX so
that we rely purely on POSIX semantics to determine the limits on I/O vector
count.
Keep the I/O vector count limit in a `SyncOnceCell` to avoid the overhead of
repeatedly calling `sysconf` as these limits are guaranteed to not change during
the lifetime of a process by POSIX.
Both Linux and MacOS enforce limits on the vector count when performing vectored
I/O via the readv and writev system calls and return EINVAL when these limits
are exceeded. This changes the standard library to handle those limits as short
reads and writes to avoid forcing its users to query these limits using
platform specific mechanisms.
Completes support for coverage in external crates
Follow-up to #74959 :
The prior PR corrected for errors encountered when trying to generate
the coverage map on source code inlined from external crates (including
macros and generics) by avoiding adding external DefIds to the coverage
map.
This made it possible to generate a coverage report including external
crates, but the external crate coverage was incomplete (did not include
coverage for the DefIds that were eliminated.
The root issue was that the coverage map was converting Span locations
to source file and locations, using the SourceMap for the current crate,
and this would not work for spans from external crates (compliled with a
different SourceMap).
The solution was to convert the Spans to filename and location during
MIR generation instead, so precompiled external crates would already
have the correct source code locations embedded in their MIR, when
imported into another crate.
@wesleywiser FYI
r? @tmandry
Co-authored-by: Weiyi Wang <wwylele@gmail.com>
Co-authored-by: Adam Reichold <adam.reichold@t-online.de>
Co-authored-by: Josh Stone <cuviper@gmail.com>
Co-authored-by: Scott McMurray <scottmcm@users.noreply.github.com>
Co-authored-by: tmiasko <tomasz.miasko@gmail.com>
The prior PR corrected for errors encountered when trying to generate
the coverage map on source code inlined from external crates (including
macros and generics) by avoiding adding external DefIds to the coverage
map.
This made it possible to generate a coverage report including external
crates, but the external crate coverage was incomplete (did not include
coverage for the DefIds that were eliminated.
The root issue was that the coverage map was converting Span locations
to source file and locations, using the SourceMap for the current crate,
and this would not work for spans from external crates (compliled with a
different SourceMap).
The solution was to convert the Spans to filename and location during
MIR generation instead, so precompiled external crates would already
have the correct source code locations embedded in their MIR, when
imported into another crate.
add `unsigned_abs` to signed integers
Mentioned on rust-lang/rfcs#2914
This PR simply adds an `unsigned_abs` to signed integers function which returns the correct absolute value as a unsigned integer.
Move bulk of BTreeMap::insert method down to new method on handle
Adjust the boundary between the map and node layers for insertion: do more in the node layer, keep root manipulation and pointer dereferencing separate. No change in undefined behaviour or performance.
r? @Mark-Simulacrum
Stabilize `Result::as_deref` and `as_deref_mut`
FCP completed in https://github.com/rust-lang/rust/issues/50264#issuecomment-645681400.
This PR stabilizes two new APIs for `std::result::Result`:
```rust
fn as_deref(&self) -> Result<&T::Target, &E> where T: Deref;
fn as_deref_mut(&mut self) -> Result<&mut T::Target, &mut E> where T: DerefMut;
```
This PR also removes two rarely used unstable APIs from `Result`:
```rust
fn as_deref_err(&self) -> Result<&T, &E::Target> where E: Deref;
fn as_deref_mut_err(&mut self) -> Result<&mut T, &mut E::Target> where E: DerefMut;
```
Closes#50264
BTreeMap: define forget_type only when relevant
Similar to `forget_node_type` for handles.
No effect on generated code, apart maybe from the superfluous calls that might not have been optimized away.
r? @Mark-Simulacrum
BTreeMap::drain_filter should not touch the root during iteration
Although Miri doesn't point it out, I believe there is undefined behaviour using `drain_filter` when draining the 11th-last element from a tree that was larger. When this happens, the last remaining child nodes are merged, the root becomes empty and is popped from the tree. That last step establishes a mutable reference to the node elected root and writes a pointer in `node::Root`, while iteration continues to visit the same node.
This is mostly code from #74437, slightly adapted.
Fix std::fs::File::metadata permission on WASI target
Previously `std::fs::File::metadata` on wasm32-wasi would call `fd_filestat_get`
to get metadata associated with fd, but that fd is opened without
RIGHTS_FD_FILESTAT_GET right, so it will failed on correctly implemented WASI
environment.
This change instead to add the missing rights when opening an fd.
Stabilize Vec::leak as a method
Closes https://github.com/rust-lang/rust/issues/62195
The signature is changed to a method rather than an associated function:
```diff
-pub fn leak<'a>(vec: Vec<T>) -> &'a mut [T]
+pub fn leak<'a>(self) -> &'a mut [T]
```
The reason for `Box::leak` not to be a method (`Deref` to an arbitrary `T` which might have its own, different `leak` method) does not apply.
