Lint overlapping ranges as a separate pass
This reworks the [`overlapping_range_endpoints`](https://doc.rust-lang.org/beta/nightly-rustc/rustc_lint_defs/builtin/static.OVERLAPPING_RANGE_ENDPOINTS.html) lint. My motivations are:
- It was annoying to have this lint entangled with the exhaustiveness algorithm, especially wrt librarification;
- This makes the lint behave consistently.
Here's the consistency story. Take the following matches:
```rust
match (0u8, true) {
(0..=10, true) => {}
(10..20, true) => {}
(10..20, false) => {}
_ => {}
}
match (true, 0u8) {
(true, 0..=10) => {}
(true, 10..20) => {}
(false, 10..20) => {}
_ => {}
}
```
There are two semantically consistent options: option 1 we lint all overlaps between the ranges, option 2 we only lint the overlaps that could actually occur (i.e. the ones with `true`). Option 1 is what this PR does. Option 2 is possible but would require the exhaustiveness algorithm to track more things for the sake of the lint. The status quo is that we're inconsistent between the two.
Option 1 generates more false postives, but I prefer it from a maintainer's perspective. I do think the difference is minimal; cases where the difference is observable seem rare.
This PR adds a separate pass, so this will have a perf impact. Let's see how bad, it looked ok locally.
This ensures that cg_clif can be built for targets that aren't natively
supported by Cranelift. It will not be possible to compile for the host
in this case, but cross-compilation will still be possible.
We won't distribute cg_clif as rustup component for any targets that
aren't natively supported by Cranelift, but will still build it if
codegen-backends lists "cranelift".
This ensures that cg_clif can be built for targets that aren't natively
supported by Cranelift. It will not be possible to compile for the host
in this case, but cross-compilation will still be possible.
We won't distribute cg_clif as rustup component for any targets that
aren't natively supported by Cranelift, but will still build it if
codegen-backends lists "cranelift".
notes
This commit extends the `#[diagnostic::on_unimplemented]` (and
`#[rustc_on_unimplemented]`) attributes to allow multiple `note`
options. This enables emitting multiple notes for custom error messages.
For now I've opted to not change any of the existing usages of
`#[rustc_on_unimplemented]` and just updated the relevant compile tests.
Rollup of 6 pull requests
Successful merges:
- #114998 (feat(docs): add cargo-pgo to PGO documentation 📝)
- #116868 (Tweak suggestion span for outer attr and point at item following invalid inner attr)
- #117240 (Fix documentation typo in std::iter::Iterator::collect_into)
- #117241 (Stash and cancel cycle errors for auto trait leakage in opaques)
- #117262 (Create a new ConstantKind variant (ZeroSized) for StableMIR)
- #117266 (replace transmute by raw pointer cast)
r? `@ghost`
`@rustbot` modify labels: rollup
Create a new ConstantKind variant (ZeroSized) for StableMIR
ZeroSized constants can be represented as `mir::Const::Val` even if their layout is not yet known. In those cases, CrateItem::body() was crashing when trying to convert a `ConstValue::ZeroSized` into its stable counterpart `ConstantKind::Allocated`.
Instead, we now map `ConstValue::ZeroSized` into a new variant: `ConstantKind::ZeroSized`.
**Note:** I didn't add any new test here since we already have covering tests in our project repository which I manually confirmed that will fix the issue.
Stash and cancel cycle errors for auto trait leakage in opaques
We don't need to emit a traditional cycle error when we have a selection error that explains what's going on but in more detail.
We may want to augment this error to actually point out the cycle, now that the cycle error is not being emitted. We could do that by storing the set of opaques that was in the `CyclePlaceholder` that gets returned from `type_of_opaque`.
r? `@oli-obk` cc `@estebank` #117235
The demangler was only needed by coverage tests, but those tests were migrated
into their own custom test mode in #112300.
This avoids having to build the demangler just for run-make tests. It will
still be built as needed by run-coverage tests or for other purposes.
Refactor some `char`, `u8` ASCII functions to be branchless
Extract conditions in singular `matches!` with or-patterns to individual `matches!` statements which enables branchless code output. The following functions were changed:
- `is_ascii_alphanumeric`
- `is_ascii_hexdigit`
- `is_ascii_punctuation`
Added codegen tests
---
Continued from https://github.com/rust-lang/rust/pull/103024.
Based on the comment from `@scottmcm` https://github.com/rust-lang/rust/pull/103024#pullrequestreview-1248697206.
The unmodified `is_ascii_*` functions didn't seem to benefit from extracting the conditions.
I've never written a codegen test before, but I tried to check that no branches were emitted.
ZeroSized constants can be represented as `mir::Const::Val` even if
their layout is not yet known. In those cases, CrateItem::body() was
crashing when trying to convert a `ConstValue::ZeroSized` into its
stable counterpart `ConstantKind::Allocated`.
Instead, we now map `ConstValue::ZeroSized` into a new variant:
`ConstantKind::ZeroSized`.
Allow target specs to use an LLD flavor, and self-contained linking components
This PR allows:
- target specs to use an LLD linker-flavor: this is needed to switch `x86_64-unknown-linux-gnu` to using LLD, and is currently not possible because the current flavor json serialization fails to roundtrip on the modern linker-flavors. This can e.g. be seen in https://github.com/rust-lang/rust/pull/115622#discussion_r1321312880 which explains where an `Lld::Yes` is ultimately deserialized into an `Lld::No`.
- target specs to declare self-contained linking components: this is needed to switch `x86_64-unknown-linux-gnu` to using `rust-lld`
- adds an end-to-end test of a custom target json simulating `x86_64-unknown-linux-gnu` being switched to using `rust-lld`
- disables codegen backends from participating because they don't support `-Zgcc-ld=lld` which is the basis of mcp510.
r? `@petrochenkov:` if the approach discussed https://github.com/rust-lang/rust/pull/115622#discussion_r1329403467 and on zulip would work for you: basically, see if we can emit only modern linker flavors in the json specs, but accept both old and new flavors while reading them, to fix the roundtrip issue.
The backwards compatible `LinkSelfContainedDefault` variants are still serialized and deserialized in `crt-objects-fallback`, while the spec equivalent of e.g. `-Clink-self-contained=+linker` is serialized into a different json object (with future-proofing to incorporate `crt-objects-fallback` in the future).
---
I've been test-driving this in https://github.com/rust-lang/rust/pull/113382 to test actually switching `x86_64-unknown-linux-gnu` to `rust-lld` (and fix what needs to be fixed in CI, bootstrap, etc), and it seems to work fine.
Decompose singular `matches!` with or-patterns to individual `matches!`
statements to enable branchless code output. The following functions
were changed:
- `is_ascii_alphanumeric`
- `is_ascii_hexdigit`
- `is_ascii_punctuation`
Add codegen tests
Co-authored-by: George Bateman <george.bateman16@gmail.com>
Co-authored-by: scottmcm <scottmcm@users.noreply.github.com>