Use PlaceRef projection abstractions more consistently in rustc_mir
PlaceRef contains abstractions for dealing with the `projections` array. This PR uses these abstractions more consistently within the `rustc_mir` crate.
See associated issue: rust-lang/rust#80647.
r? `@RalfJung`
Don't use posix_spawn_file_actions_addchdir_np on macOS.
There is a bug on macOS where using `posix_spawn_file_actions_addchdir_np` with a relative executable path will cause `posix_spawnp` to return ENOENT, even though it successfully spawned the process in the given directory.
`posix_spawn_file_actions_addchdir_np` was introduced in macOS 10.15 first released in Oct 2019. I have tested macOS 10.15.7 and 11.0.1.
Example offending program:
```rust
use std::fs;
use std::os::unix::fs::PermissionsExt;
use std::process::*;
fn main() {
fs::create_dir_all("bar").unwrap();
fs::create_dir_all("foo").unwrap();
fs::write("foo/foo.sh", "#!/bin/sh\necho hello ${PWD}\n").unwrap();
let perms = fs::Permissions::from_mode(0o755);
fs::set_permissions("foo/foo.sh", perms).unwrap();
let c = Command::new("../foo/foo.sh").current_dir("bar").spawn();
eprintln!("{:?}", c);
}
```
This prints:
```
Err(Os { code: 2, kind: NotFound, message: "No such file or directory" })
hello /Users/eric/Temp/bar
```
I wanted to open this PR to get some feedback on possible solutions. Alternatives:
* Do nothing.
* Document the bug.
* Try to detect if the executable is a relative path on macOS, and avoid using `posix_spawn_file_actions_addchdir_np` only in that case.
I looked at the [XNU source code](https://opensource.apple.com/source/xnu/xnu-6153.141.1/bsd/kern/kern_exec.c.auto.html), but I didn't see anything obvious that would explain the behavior. The actual chdir succeeds, it is something else further down that fails, but I couldn't see where.
EDIT: I forgot to mention, relative exe paths with `current_dir` in general are discouraged (see #37868). I don't know if #37868 is fixable, since normalizing it would change the semantics for some platforms. Another option is to convert the executable to an absolute path with something like joining the cwd with the new cwd and the executable, but I'm uncertain about that.
Don't make tools responsible for checking unknown and renamed lints
Previously, clippy (and any other tool emitting lints) had to have their
own separate UNKNOWN_LINTS pass, because the compiler assumed any tool
lint could be valid. Now, as long as any lint starting with the tool
prefix exists, the compiler will warn when an unknown lint is present.
This may interact with the unstable `tool_lint` feature, which I don't entirely understand, but it will take the burden off those external tools to add their own lint pass, which seems like a step in the right direction to me.
- Don't mark `ineffective_unstable_trait_impl` as an internal lint
- Use clippy's more advanced lint suggestions
- Deprecate the `UNKNOWN_CLIPPY_LINTS` pass (and make it a no-op)
- Say 'unknown lint `clippy::x`' instead of 'unknown lint x'
This is tested by existing clippy tests. When https://github.com/rust-lang/rust/pull/80527 merges, it will also be tested in rustdoc tests. AFAIK there is no way to test this with rustc directly.
Before:
```
thread 'rustc' panicked at 'attempt to read from stolen value', /home/joshua/rustc/compiler/rustc_data_structures/src/steal.rs:43:15
```
After:
```
thread 'rustc' panicked at 'attempt to steal from stolen value', compiler/rustc_mir/src/transform/mod.rs:423:25
```
Add NonZeroUn::is_power_of_two
This saves instructions on both new and old machines <https://rust.godbolt.org/z/4fjTMz>
- On the default x64 target (with no fancy instructions available) it saves a few instructions by not needing to also check for zero.
- On newer targets (with BMI1) it uses `BLSR` for super-short assembly.
This can be used for things like checks against alignments stored in `NonZeroUsize`.
Use Option::unwrap_or instead of open-coding it
r? ```@oli-obk``` Noticed this while we were talking about the other PR just now 😆
```@rustbot``` modify labels +C-cleanup +T-compiler
Force vec![] to expression position only
r? `@oli-obk`
I went with the lazy way of only changing what broke. I moved the test to ui/macros because the diagnostics no longer give suggestions.
Closes#61933
Support non-stage0 check
Seems to work locally - a full stage 1 check succeeds, building std (because we can't get away with checking it), and then checking the compiler and other tools. This ran into the problem that a unconditional x.py check in stage 1 *both* checks and builds stage 1 std, and then has to clean up because for some reason the rmeta and rlib artifacts conflict (though I'm not actually entirely sure why, but it doesn't seem worth digging in in too much detail).
Ideally we wouldn't be building and checking like that but it's a minor worry as checking std is pretty fast and you can avoid it if you're aiming for speed by passing the compiler (e.g., compiler/rustc) explicitly.
r? ```@jyn514```
Allow downloading LLVM on Windows and MacOS
- Don't ignore packaging `llvm/lib/` for `rust-dev` when LLVM is linked
statically
- Add `link-type.txt` so bootstrap knows whether llvm was linked
statically or dynamically
- Don't assume CI LLVM is linked dynamically in `bootstrap::config`
- Fall back to dynamic linking if `link-type.txt` doesn't exist
- Fix existing bug that split the output of `llvm-config` on lines, not spaces
- Only special case MacOS when dynamic linking. Static linking works fine.
- Enable building LLVM tests
This works around the following llvm bug:
```
llvm-config: error: component libraries and shared library
llvm-config: error: missing: /home/joshua/rustc2/build/x86_64-unknown-linux-gnu/llvm/build/lib/libgtest.a
llvm-config: error: missing: /home/joshua/rustc2/build/x86_64-unknown-linux-gnu/llvm/build/lib/libgtest_main.a
llvm-config: error: missing: /home/joshua/rustc2/build/x86_64-unknown-linux-gnu/llvm/build/lib/libLLVMTestingSupport.a
thread 'main' panicked at 'command did not execute successfully: "/home/joshua/rustc2/build/x86_64-unknown-linux-gnu/llvm/build/bin/llvm-config" "--libfiles"
```
I'm not sure why llvm-config thinks these are required, but to avoid
the error, this builds them anyway.
- Bump version of `download-ci-llvm-stamp`
`src/llvm-project` hasn't changed, but the generated tarball has.
Fixes https://github.com/rust-lang/rust/issues/77084.
# Current Status
This works on both MacOS and Windows! 🎉🎉 Thanks to ```@nagisa,``` ```@halkcyon,``` ```@Lokathor,``` ```@jryans,``` and ```@poliorcetics``` for helping me test!
The `if-available` check now supports all tier 1 platforms. Although only x64 apple and x64 msvc have been tested, none of the changes here are Windows or Mac specific, and I expect this to work anywhere that LLVM artifacts are uploaded to CI (i.e. the `rust-dev` component exists).
## Windows
Note that if you have an old version of MSVC build tools you'll need to update them. VS Build Tools 2019 14.28 and later are known to work. With old tools, you may see an error like the following:
```
error LNK2001: unresolved external symbol __imp___std_init_once_complete
```
resolve: Simplify collection of traits in scope
"Traits in scope" for a given location are collected by walking all scopes in type namespace, collecting traits in them and pruning traits that don't have an associated item with the given name and namespace.
Previously we tried to prune traits using some kind of hygienic resolution for associated items, but that was complex and likely incorrect, e.g. in #80762 correction to visibilites of trait items caused some traits to not be in scope anymore.
I previously had some comments and concerns about this in https://github.com/rust-lang/rust/pull/65351.
In this PR we are doing some much simpler pruning based on `Symbol` and `Namespace` comparisons, it should be enough to throw away 99.9% of unnecessary traits.
It is not necessary for pruning to be precise because for trait aliases, for example, we don't do any pruning at all, and precise hygienic resolution for associated items needs to be done in typeck anyway.
The somewhat unexpected effect is that trait imports introduced by macros 2.0 now bring traits into scope due to the removed hygienic check on associated item names.
I'm not sure whether it is desirable or not, but I think it's acceptable for now.
The old check was certainly incorrect because macros 2.0 did bring trait aliases into scope.
If doing this is not desirable, then we should come up with some other way to avoid bringing traits from macros 2.0 into scope, that would accommodate for trait aliases as well.
---
The PR also contains a couple of pure refactorings
- Scope walk is done by using `visit_scopes` instead of a hand-rolled version.
- Code is restructured to accomodate for rustdoc that also wants to query traits in scope, but doesn't want to filter them by associated items at all.
r? ```@matthewjasper```
Improve diagnostics when closure doesn't meet trait bound
Improves the diagnostics when closure doesn't meet trait bound by modifying `TypeckResuts::closure_kind_origins` such that `hir::Place` is used instead of `Symbol`. Using `hir::Place` to describe which capture influenced the decision of selecting a trait a closure satisfies to (Fn/FnMut/FnOnce, Copy) allows us to show precise path in the diagnostics when `capture_disjoint_field` feature is enabled.
Closes rust-lang/project-rfc-2229/issues/21
r? ```@nikomatsakis```
Add benchmark and fast path for BufReader::read_exact
At work, we have a wrapper type that implements this optimization. It would be nice if the standard library were faster.
Before:
```
test io::buffered::tests::bench_buffered_reader_small_reads ... bench: 7,670 ns/iter (+/- 45)
```
After:
```
test io::buffered::tests::bench_buffered_reader_small_reads ... bench: 4,457 ns/iter (+/- 41)
```
resolve: Reject ambiguity built-in attr vs different built-in attr
Fixes https://github.com/rust-lang/rust/issues/79798.
Resolution ensures that inert attributes cannot be used through imports like this, but built-in attributes don't go through initial resolution (only through resolution validation), so we have to keep some extra data (the built-in attribute name) to prevent it from happening.
correctly deal with late-bound lifetimes in anon consts
adds support for using late bound lifetimes of the parent context in anon consts.
```rust
#![feature(const_generics)]
const fn inner<'a>() -> usize where &'a (): Sized { 3 }
fn test<'a>() {
let _: [u8; inner::<'a>()];
}
```
The lifetime `'a` is late bound in `test` so it's not included in its generics but is instead dealt with separately in borrowck.
This didn't previously work for anon consts as they have to use the late bound lifetimes of their parent which has
to be explicitly handled.
r? ```@matthewjasper``` cc ```@varkor``` ```@eddyb```
BTreeMap: expose new_internal function and sanitize from_new_internal
`new_internal` is the functional core of the imperative `push_internal_level`, and `from_new_internal` can easily do a proper job instead of returning a half-baked node.
r? `@Mark-Simulacrum`
Add `as_rchunks` (and friends) to slices
`@est31` mentioned (https://github.com/rust-lang/rust/issues/76354#issuecomment-717027175) that, for completeness, there needed to be an `as_chunks`-like method that chunks from the end (with the remainder at the beginning) like `rchunks` does.
So here's a PR for `as_rchunks: &[T] -> (&[T], &[[T; N]])` and `as_rchunks_mut: &mut [T] -> (&mut [T], &mut [[T; N]])`.
But as I was doing this and copy-pasting `from_raw_parts` calls, I thought that I should extract that into an unsafe method. It started out a private helper, but it seemed like `as_chunks_unchecked` could be reasonable as a "real" method, so I added docs and made it public. Let me know if you think it doesn't pull its weight.
