The default implementations of several `Iterator` methods use `fold` or
`try_fold`, which works, but is overkill for slices and bloats the
amount of LLVM IR generated and consequently hurts compile times.
This commit adds the simple, obvious implementations for `for_each`,
`all`, `any`, `find`, `find_map`, and simplifies the existing
implementations for `position` and `rposition`. These changes reduce
compile times significantly on some benchmarks.
WSL1 does not support `fcntl`-based lock and will always report success,
therefore creating a race condition when multiple rustc processes are
modifying shared data such as `search-index.js`. WSL1 does however
support `flock`.
`flock` is supported by all unix-like platforms. The only caveat is that
Linux 2.6.11 or earlier does not support `flock` on NFS mounts, but as
the minimum supported Linux version is 2.6.18, it is not an issue.
Fixes#72157
`DroplessArena` and `TypedArena` use an aggressive growth strategy: the
first chunk is 4 KiB, the second is 8 KiB, and it keeps on doubling
indefinitely. DHAT profiles show that sometimes this results in large
chunks (e.g. 16-128 MiB) that are barely filled. Although these don't
contribute to RSS, they clog up the DHAT profiles.
This commit changes things so that the doubling stops at 2 MiB. This is
large enough that chunk allocations are still rare (you might get 100s
instead of 10s of them) but avoids lots of unused space in the worst
case. It gives a slight speed-up to cycle counts in some cases.
For the given code paths, the amount of space used in the previous chunk
is irrelevant.
(This will almost never make a difference to behaviour, but it makes the
code clearer.)
This stabilizes process_set_argv0 targeting 1.45.0. It has been
useful in practice and seems useful as-is.
The equivalent feature could be implemented for Windows, but as far as I
know nobody has. That can be done separately.
Tracking issue: #66510
Rollup of 5 pull requests
Successful merges:
- #71737 (Miri: run liballoc tests with threads)
- #71928 (Add strikethrough support to rustdoc)
- #72048 (Visit move out of `_0` when visiting `return`)
- #72096 (Make MIR typeck use `LocalDefId` and fix docs)
- #72128 (strings do not have to be valid UTF-8 any more)
Failed merges:
r? @ghost
The amortized case is much more common than the exact case, and it is
typically instantiated many times.
Also, we can put a chunk of the code into a function that isn't generic
over T, which reduces the amount of LLVM IR generated quite a lot,
improving compile times.
It's only used once, for `VecDeque`, and can easily be replaced by
something else. The commit changes `grow_if_necessary` to `grow` to
avoid some small regressions caused by changed inlining.
The commit also removes `Strategy::Double`, and streamlines the
remaining variants of `Strategy`.
It's a compile time win on some benchmarks because the many
instantations of `RawVec::grow` are a little smaller.
I also added test cases to make sure the optimization can fire on all of
these cases:
```rust
fn case_1(o: Option<u8>) -> Option<u8> {
match o {
Some(u) => Some(u),
None => None,
}
}
fn case2(r: Result<u8, i32>) -> Result<u8, i32> {
match r {
Ok(u) => Ok(u),
Err(i) => Err(i),
}
}
fn case3(r: Result<u8, i32>) -> Result<u8, i32> {
let u = r?;
Ok(u)
}
```
Without MIR inlining, this still does not completely optimize away the
`?` operator because the `Try::into_result()`, `From::from()` and
`Try::from_error()` calls still exist. This does move us a bit closer to
that goal though because:
- We can now run the pass on mir-opt-level=1
- We no longer depend on the copy propagation pass running which is
unlikely to stabilize anytime soon.
Given code like `v[&field].boo();` where `field: String` and
`.boo(&mut self)`, typeck will have decided that `v` is accessed using
`Index`, but when `boo` adds a new `mut` obligation,
`convert_place_op_to_mutable` is called. When this happens, for *some
reason* the arguments' dereference adjustments are completely ignored
causing an error saying that `IndexMut` is not satisfied:
```
error[E0596]: cannot borrow data in an index of `Indexable` as mutable
--> src/main.rs:30:5
|
30 | v[&field].boo();
| ^^^^^^^^^ cannot borrow as mutable
|
= help: trait `IndexMut` is required to modify indexed content, but it is not implemented for `Indexable`
```
This is not true, but by changing `try_overloaded_place_op` to retry
when given `Needs::MutPlace` without passing the argument types, the
example successfully compiles.
I believe there might be more appropriate ways to deal with this.
Use CDN for ci-caches on download
This will reduce costs, as well as lays the groundwork for developers to be able
to locally pull the published docker images without needing AWS credentials.
r? @pietroalbini
