Rollup of 7 pull requests
Successful merges:
- #126923 (test: dont optimize to invalid bitcasts)
- #127090 (Reduce merge conflicts from rustfmt's wrapping)
- #127105 (Only update `Eq` operands in GVN if it can update both sides)
- #127150 (Fix x86_64 code being produced for bare-metal LoongArch targets' `compiler_builtins`)
- #127181 (Introduce a `rustc_` attribute to dump all the `DefId` parents of a `DefId`)
- #127182 (Fix error in documentation for IpAddr::to_canonical and Ipv6Addr::to_canonical)
- #127191 (Ensure `out_of_scope_macro_calls` lint is registered)
r? `@ghost`
`@rustbot` modify labels: rollup
Automatically taint InferCtxt when errors are emitted
r? `@nnethercote`
Basically `InferCtxt::dcx` now returns a `DiagCtxt` that refers back to the `Cell<Option<ErrorGuaranteed>>` of the `InferCtxt` and thus when invoking `Diag::emit`, and the diagnostic is an error, we taint the `InferCtxt` directly.
That change on its own has no effect at all, because `InferCtxt` already tracks whether errors have been emitted by recording the global error count when it gets opened, and checking at the end whether the count changed. So I removed that error count check, which had a bit of fallout that I immediately fixed by invoking `InferCtxt::dcx` instead of `TyCtxt::dcx` in a bunch of places.
The remaining new errors are because an error was reported in another query, and never bubbled up. I think they are minor enough for this to be ok, and sometimes it actually improves diagnostics, by not silencing useful diagnostics anymore.
fixes#126485 (cc `@olafes)`
There are more improvements we can do (like tainting in hir ty lowering), but I would rather do that in follow up PRs, because it requires some refactorings.
coverage: Avoid getting extra unexpansion info when we don't need it
Several callers of `unexpand_into_body_span_with_visible_macro` would immediately discard the additional macro-related information, which is wasteful. We can avoid this by having them instead call a simpler method that just returns the span they care about.
This PR also moves the relevant functions out of `coverage::spans::from_mir` and into a new submodule `coverage::unexpand`, so that calling them from `coverage::mappings` is less awkward.
There should be no actual changes to coverage-instrumentation output, as demonstrated by the absence of test updates.
Avoid cloning jump threading state when possible
The current implementation of jump threading passes most of its time cloning its state. This PR attempts to avoid such clones by special-casing the last predecessor when recursing through a terminator.
This is not optimal, but a first step while I refactor the state data structure to be sparse.
The two other commits are drive-by.
Fixes https://github.com/rust-lang/rust/issues/116721
r? `@oli-obk`
These particular callers don't actually use the returned macro information, so
they can use a simpler span-unexpansion function that doesn't return it.
coverage: Make `#[coverage(..)]` apply recursively to nested functions
This PR makes the (currently-unstable) `#[coverage(off)]` and `#[coverage(on)]` attributes apply recursively to all nested functions/closures, instead of just the function they are directly attached to.
Those attributes can now also be applied to modules and to impl/impl-trait blocks, where they have no direct effect, but will be inherited by all enclosed functions/closures/methods that don't override the inherited value.
---
Fixes#126625.
Remove more `PtrToPtr` casts in GVN
This addresses two things I noticed in MIR:
1. `NonNull::<T>::eq` does `(a as *mut T) == (b as *mut T)`, but it could just compare the `*const T`s, so this removes `PtrToPtr` casts that are on both sides of a pointer comparison, so long as they're not fat-to-thin casts.
2. `NonNull::<T>::addr` does `transmute::<_, usize>(p as *const ())`, but so long as `T: Thin` that cast doesn't do anything, and thus we can directly transmute the `*const T` instead.
r? mir-opt
Save 2 pointers in `TerminatorKind` (96 → 80 bytes)
These things don't need to be `Vec`s; boxed slices are enough.
The frequent one here is call arguments, but MIR building knows the number of arguments from the THIR, so the collect is always getting the allocation right in the first place, and thus this shouldn't ever add the shrink-in-place overhead.
These things don't need to be `Vec`s; boxed slices are enough.
The frequent one here is call arguments, but MIR building knows the number of arguments from the THIR, so the collect is always getting the allocation right in the first place, and thus this shouldn't ever add the shrink-in-place overhead.
`PtrMetadata` doesn't care about `*const`/`*mut`/`&`/`&mut`, so GVN away those casts in its argument.
This includes updating MIR to allow calling PtrMetadata on references too, not just raw pointers. That means that `[T]::len` can be just `_0 = PtrMetadata(_1)`, for example.
# Conflicts:
# tests/mir-opt/pre-codegen/slice_index.slice_get_unchecked_mut_range.PreCodegen.after.panic-abort.mir
# tests/mir-opt/pre-codegen/slice_index.slice_get_unchecked_mut_range.PreCodegen.after.panic-unwind.mir
Account for things that optimize out in inlining costs
This updates the MIR inlining `CostChecker` to have both bonuses and penalties, rather than just penalties.
That lets us add bonuses for some things where we want to encourage inlining without risking wrapping into a gigantic cost. For example, `switchInt(const …)` we give an inlining bonus because codegen will actually eliminate the branch (and associated dead blocks) once it's monomorphized, so measuring both sides of the branch gives an unrealistically-high cost to it. Similarly, an `unreachable` terminator gets a small bonus, because whatever branch leads there doesn't actually exist post-codegen.
Clean up some comments near `use` declarations
#125443 will reformat all `use` declarations in the repository. There are a few edge cases involving comments on `use` declarations that require care. This PR cleans up some clumsy comment cases, taking us a step closer to #125443 being able to merge.
r? ``@lqd``
Stabilise `c_unwind`
Fix#74990Fix#115285 (that's also where FCP is happening)
Marking as draft PR for now due to `compiler_builtins` issues
r? `@Amanieu`
Most modules have such a blank line, but some don't. Inserting the blank
line makes it clearer that the `//!` comments are describing the entire
module, rather than the `use` declaration(s) that immediately follows.
Apparently MIR borrowck cares about at least one of these for checking variance.
In runtime MIR, though, there's no need for them as `PtrToPtr` does the same thing.
(Banning them simplifies passes like GVN that no longer need to handle multiple cast possibilities.)
Replace all `&DiagCtxt` with a `DiagCtxtHandle<'_>` wrapper type
r? `@davidtwco`
This paves the way for tracking more state (e.g. error tainting) in the diagnostic context handle
Basically I will add a field to the `DiagCtxtHandle` that refers back to the `InferCtxt`'s (and others) `Option<ErrorHandled>`, allowing us to immediately taint these contexts when emitting an error and not needing manual tainting anymore (which is easy to forget and we don't do in general anyway)
coverage: Add debugging flag `-Zcoverage-options=no-mir-spans`
When set, this flag skips the code that normally extracts coverage spans from MIR statements and terminators. That sometimes makes it easier to debug branch coverage and MC/DC coverage instrumentation, because the coverage output is less noisy.
For internal debugging only. If future code changes would make it hard to keep supporting this flag, it should be removed at that time.
`@rustbot` label +A-code-coverage
Rename `InstanceDef` -> `InstanceKind`
Renames `InstanceDef` to `InstanceKind`. The `Def` here is confusing, and makes it hard to distinguish `Instance` and `InstanceDef`. `InstanceKind` makes this more obvious, since it's really just describing what *kind* of instance we have.
Not sure if this is large enough to warrant a types team MCP -- it's only 53 files. I don't personally think it does, but happy to write one if anyone disagrees. cc ``@rust-lang/types``
r? types
When set, this flag skips the code that normally extracts coverage spans from
MIR statements and terminators. That sometimes makes it easier to debug branch
coverage and MC/DC coverage, because the coverage output is less noisy.
For internal debugging only. If other code changes would make it hard to keep
supporting this flag, remove it.
coverage: Several small improvements to graph code
This PR combines a few small improvements to coverage graph handling code:
- Remove some low-value implementation tests that were getting in the way of other changes.
- Clean up `pub` visibility.
- Flatten some code using let-else.
- Prefer `.copied()` over `.cloned()`.
`@rustbot` label +A-code-coverage
