Replace pthread `RwLock` with custom implementation
This is one of the last items in #93740. I'm doing `RwLock` first because it is more self-contained and has less tradeoffs to make. The motivation is explained in the documentation, but in short: the pthread rwlock is slow and buggy and `std` can do much better. I considered implementing a parking lot, as was discussed in the tracking issue, but settled for the queue-based version because writing self-balancing binary trees is not fun in Rust...
This is a rather complex change, so I have added quite a bit of documentation to help explain it. Please point out any part that could be explained better.
~~The read performance is really good, I'm getting 4x the throughput of the pthread version and about the same performance as usync/parking_lot on an Apple M1 Max in the usync benchmark suite, but the write performance still falls way behind what usync and parking_lot achieve. I tried using a separate queue lock like what usync uses, but that didn't help. I'll try to investigate further in the future, but I wanted to get some eyes on this first.~~ [Resolved](https://github.com/rust-lang/rust/pull/110211#issuecomment-1513682336)
r? `@m-ou-se`
CC `@kprotty`
Avoid accessing the HIR in the happy path of `coherent_trait`
Unfortunately the hir is still used in unsafety checks, and we do not have a way to avoid that. An impl's unsafety is not part of any query other than hir.
So this PR does not affect perf, but could still be considered a cleanup
A trait's local impls are trivially coherent if there are no impls.
This avoids creating a dependency edge on the hir or the specialization graph
This may resolve part of the performance issue of https://github.com/rust-lang/rust/pull/120558
[docs] Update armv6k-nintendo-3ds platform docs for outdated info
Mostly just fixing links and references to renamed crates, but also updating a bit of outdated info as well.
CC `@Meziu` `@AzureMarker`
Encode `coroutine_for_closure` for foreign crates
Async closures (and "coroutine closures" in general) need to have their child coroutine encoded. This PR does that.
r? oli-obk
assert_unsafe_precondition cleanup
I moved the polymorphic `is_nonoverlapping` into the `Cell` function that uses it and renamed `intrinsics::is_nonoverlapping_mono` to just `intrinsics::is_nonoverlapping`.
We now also have some docs for `intrinsics::debug_assertions`.
r? RalfJung
Make cmath.rs a single file
It makes sense to have this all in one file. There's essentially only one target that has missing symbols and that's easy enough to handle inline.
Note that the Windows definitions used to use `c_float` and `c_double` whereas the other platforms all used `f32` and `f64`. They've now been made consistent. However, `c_float` and `c_double` have the expected definitions on all Windows platforms we support.
Create try_new function for ThinBox
The `allocator_api` feature has proven very useful in my work in the FreeBSD kernel. I've found a few places where a `ThinBox` #92791 would be useful, but it must be able to be fallibly allocated for it to be used in the kernel.
This PR proposes a change to add such a constructor for ThinBox.
ACP: https://github.com/rust-lang/libs-team/issues/213
Assert that params with the same *index* have the same *name*
Found this bug when trying to build libcore with the new solver, since it will canonicalize two params with the same index into *different* placeholders if those params differ by name.
always run `configure_linker` except for mir-opt tests
`configure_linker` now runs consistently unless it's for mir-opt tests. Previously `!= "check"` condition was causing dirt in the cargo cache between runs of `x anything-but-not-check` and `x check`.
Fixes#120768
cc `@saethlin`
Rollup of 10 pull requests
Successful merges:
- #117740 (Add some links and minor explanatory comments to `std::fmt`)
- #118307 (Remove an unneeded helper from the tuple library code)
- #119242 (Suggest less bug-prone construction of Duration in docs)
- #119449 (Fix `clippy::correctness` in the library)
- #120307 (core: add Duration constructors)
- #120459 (Document various I/O descriptor/handle conversions)
- #120729 (Update mdbook to 0.4.37)
- #120763 (Suggest pattern tests when modifying exhaustiveness)
- #120906 (Remove myself from some review rotations)
- #120916 (Subtree update of ` rust-analyzer`)
r? `@ghost`
`@rustbot` modify labels: rollup
Downgrade xcode
This is a temporary fix for the CI issues that have been plaguing the macOS builders. GitHub updated the default Xcode to 15 in the [2024-02-04](https://github.com/actions/runner-images/releases/tag/macos-13%2F20240204.1) update. This caused two issues to start appearing in CI:
* cmake fails to verify that clang can build a simple test program.
* An `invalid r_symbolnum` linking error when trying to build one of cranelift's tests.
I believe I have a solution for the first problem, but not the second. In the meantime, to help with the CI problems, this PR should temporarily resolve the issue until we have a solution.
Suggest pattern tests when modifying exhaustiveness
The vast majority of exhaustiveness tests are in `tests/ui/pattern`, this is what I've been using for years. This PR is me telling `x suggest` about that.
cc `@Ezrashaw`
Update mdbook to 0.4.37
This updates mdbook to 0.4.37.
Changelog: https://github.com/rust-lang/mdBook/blob/master/CHANGELOG.md#mdbook-0437
The primary change is the update to pulldown-cmark which has a large number of markdown parsing changes. There shouldn't be any significant changes to the rendering of any of the books (I have posted some PRs to fix some minor issues to the ones that were affected).
core: add Duration constructors
Add more `Duration` constructors.
Tracking issue: #120301.
These match similar convenience constructors available on both `chrono::Duration` and `time::Duration`.
What's the best ordering for these with respect to the existing constructors?
Suggest less bug-prone construction of Duration in docs
std::time::Duration has a well-known quirk: Duration::as_nanos() returns u128 [1], but Duration::from_nanos() takes u64 [2]. So these methods cannot easily roundtrip [3]. It is not possible to simply accept u128 in from_nanos [4], because it requires breaking other API [5].
It seems to me that callers have basically only two options:
1. `Duration::from_nanos(d.as_nanos() as u64)`, which is the "obvious" and buggy approach.
2. `Duration::new(d.as_secs(), d.subsecs_nanos())`, which only becomes apparent after reading and digesting the entire Duration struct documentation.
I suggest that the documentation of `from_nanos` is changed to make option 2 more easily discoverable.
There are two major usecases for this:
- "Weird math" operations that should not be supported directly by `Duration`, like squaring.
- "Disconnected roundtrips", where the u128 value is passed through various other stack frames, and perhaps reconstructed into a Duration on a different machine.
In both cases, it seems like a good idea to not tempt people into thinking "Eh, u64 is good enough, what could possibly go wrong!". That's why I want to add a note that points out the similarly-easy and *safe* way to reconstruct a Duration.
[1] https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.as_nanos
[2] https://doc.rust-lang.org/stable/std/time/struct.Duration.html#method.from_nanos
[3] https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=fa6bab2b6b72f20c14b5243610ea1dde
[4] https://github.com/rust-lang/rust/issues/103332
[5] https://github.com/rust-lang/rust/issues/51107#issuecomment-392353166
Remove an unneeded helper from the tuple library code
Thanks to https://github.com/rust-lang/rust/pull/107022, this is just what `==` does, so we don't need the helper here anymore.
Add some links and minor explanatory comments to `std::fmt`
I thought the documentation for the `#` flag could do with a link to the explanation of the `?xXbo` flags, because at that point they haven't been explained yet and it's a bit confusing.
I also added that the `0` flag overrides the fill character and alignment flag, here's a [Rust Playgrond](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=0d580b7b78b8a2d8c08a2fc7a936ef17) that shows what I mean.
Allowing the Xcode version to "float" based on whatever default GitHub
selects creates an unreliable environment. When GitHub changes the
default, we can have multiple jobs in the same run using different
versions as it rolls out across machines. It can also cause oscillation
between runs as different machines are used. It also causes
unpredictable timing when the updates happen.
This change helps ensure that the version that is used is pinned. The
downside is that it requires manually bumping the version, and the risk
that if we take too long, older Xcodes will be removed and that will
break the build.
This seems to fix two sporadic errors that have been appearing in CI.
One is an issue with cmake being unable to verify that cmake is able to
build a simple test program. The other is a `invalid r_symbolnum`
linking error when trying to build one of cranelift's tests.
This is intended as a temporary fix until we can figure out how to
resolve those issues.
Fold pointer operations in GVN
This PR proposes 2 combinations of cast operations in MIR GVN:
- a chain of `PtrToPtr` or `MutToConstPointer` casts can be folded together into a single `PtrToPtr` cast;
- we attempt to evaluate more ptr ops when there is no provenance.
In particular, this allows to read from static slices.
This is not yet sufficient to see through slice operations that use `PtrComponents` (because that's a union), but still a step forward.
r? `@ghost`
Add support for custom JSON targets when using build-std.
Currently, when building with `build-std`, some library build scripts check properties of the target by inspecting the target triple at `env::TARGET`, which is simply set to the filename of the JSON file when using JSON target files.
This patch alters these build scripts to use `env::CARGO_CFG_*` to fetch target information instead, allowing JSON target files describing platforms without `restricted_std` to build correctly when using `-Z build-std`. There are some weak assertions here (for example, `nintendo && newlib`), however this seems at least a marginal improvement on the existing solution.
Fixes https://github.com/rust-lang/wg-cargo-std-aware/issues/60.
Print kind of coroutine closure
Make sure that we print "async closure" when we have an async closure, rather than calling it generically a ["coroutine-closure"](https://github.com/rust-lang/rust/pull/120361).
Fixes#120886
r? oli-obk
Adapt `llvm-has-rust-patches` validation to take `llvm-config` into account.
This adapts an assertion that was added in #119556.
The current assertion does not take the `llvm-config` setting into accounts, which does not match the `llvm-has-rust-patches` documentation, which states:
> This would be used in conjunction with either an llvm-config or build.submodules = false.
(It also breaks my workflow: I build LLVM separately, but do have the rust patches applied).
---
**edit:** Originally this PR just removed the assertion, but it now implements the alternative mentioned here:
An alternative fix would be to take `llvm-config` into account in the assertion, but to me the assertion seems to provide little value, thus the simpler fix of just removing it.
cc `@onur-ozkan,` in case I'm missing a reason to keep the assertion.
large_assignments: Allow moves into functions
Moves into functions are typically implemented with pointer passing
rather than memcpy's at the llvm-ir level, so allow moves into
functions.
Part of the "Differentiate between Operand::Move and Operand::Copy" step of https://github.com/rust-lang/rust/issues/83518.
r? `@oli-obk` (who I think is still E-mentor?)
Suppress suggestions in derive macro
close#118809
I suppress warnings inside derive macros.
For example, the compiler emits following error by a program described in https://github.com/rust-lang/rust/issues/118809#issuecomment-1852256687 with a suggestion that indicates invalid syntax.
```
error[E0308]: `?` operator has incompatible types
--> src/main.rs:3:17
|
3 | #[derive(Debug, Deserialize)]
| ^^^^^^^^^^^ expected `u32`, found `u64`
|
= note: `?` operator cannot convert from `u64` to `u32`
= note: this error originates in the derive macro `Deserialize` (in Nightly builds, run with -Z macro-backtrace for more info)
help: you can convert a `u64` to a `u32` and panic if the converted value doesn't fit
|
3 | #[derive(Debug, Deserialize.try_into().unwrap())]
| ++++++++++++++++++++
For more information about this error, try `rustc --explain E0308`.
error: could not compile `serde_test` (bin "serde_test") due to 2 previous errors
```
In this PR, suggestions to cast are suppressed.
```
error[E0308]: `?` operator has incompatible types
--> src/main.rs:3:17
|
3 | #[derive(Debug, Deserialize)]
| ^^^^^^^^^^^ expected `u32`, found `u64`
|
= note: `?` operator cannot convert from `u64` to `u32`
= note: this error originates in the derive macro `Deserialize` (in Nightly builds, run with -Z macro-backtrace for more info)
For more information about this error, try `rustc --explain E0308`.
error: could not compile `serde_test` (bin "serde_test") due to 2 previous errors
```
Tristan F