Fall back to the unoptimized implementation in read_binary_file if File::metadata lies
Fixes https://github.com/rust-lang/rust/issues/115458
r? `@jackh726` because you approved the previous PR
Simplify/Optimize FileEncoder
FileEncoder is basically a BufWriter except that it exposes access to the not-written-to-yet region of the buffer so that some users can write directly to the buffer. This strategy is awesome because it lets us avoid calling memcpy for small copies, but the previous strategy was based on the writer accessing a `&mut [MaybeUninit<u8>; N]` and returning a `&[u8]` which is an API which currently mandates the use of unsafe code, making that interface in general not that appealing.
So this PR cleans up the FileEncoder implementation and builds on that general idea of direct buffer access in order to prevent `memcpy` calls in a few key places when encoding the dep graph and rmeta tables. The interface used here is now 100% safe, but with the caveat that internally we need to avoid trusting the number of bytes that the provided function claims to have written.
The original primary objective of this PR was to clean up the FileEncoder implementation so that the fix for the following issues would be easy to implement. The fix for these issues is to correctly update self.buffered even when writes fail, which I think it's easy to verify manually is now done, because all the FileEncoder methods are small.
Fixes https://github.com/rust-lang/rust/issues/115298
Fixes https://github.com/rust-lang/rust/issues/114671
Fixes https://github.com/rust-lang/rust/issues/114045
Fixes https://github.com/rust-lang/rust/issues/108100
Fixes https://github.com/rust-lang/rust/issues/106787
rustc_target/loongarch: Fix passing of transparent unions with only one non-ZST member
This ensures that `MaybeUninit<T>` has the same ABI as `T` when passed through an `extern "C"` function.
Fixes https://github.com/rust-lang/rust/issues/115509
r? `@bjorn3`
adjust ConstValue::Slice to work for arbitrary slice types
valtrees have already been assuming that this works; this PR makes it a reality. Also further restrict `ConstValue::Slice` to what it is actually used for; this even shrinks `ConstValue` from 32 to 24 bytes which is a nice win. :)
The alternative to this approach is to make `ConstValue::Slice` work really only for `&str`/`&[u8]` literals, and never return it in `op_to_const`. That would make `op_to_const` very clean. We could then even remove the `meta` field; the length would always be `data.inner().len()`. We could *almost* just use a `Symbol` instead of a `ConstAllocation`, but we have to support byte strings and there doesn't seem to be an interned representation of them (or rather, `ConstAllocation` *is* their interned representation). In this world, valtrees of slice reference types would then become noticeably more expensive to turn into a `ConstValue` -- but does that matter? Specifically for `&str`/`&[u8]` we could still use the optimized representation if we wanted.
If byte strings were already interned somewhere I'd gravitate towards the alternative, but the way things stand, we need a `ConstAllocation` case anyway to support byte strings, and then we might as well support arbitrary slices. (Or we say that byte strings don't get an optimized representation at all. Such a performance cliff between `str` and byte strings is probably unexpected, though due to the lack of interning for byte strings I think there might already be a performance cliff there.)
coverage: Remove debug code from the instrumentor
The coverage instrumentor has an entire module full of complex code that is only used for debugging.
And as I continue to work on coverage, I keep finding that this debug code is constantly causing more trouble than it's worth. It's deeply entangled with current implementation details, such that making any non-trivial change to the instrumentor usually requires major changes to the debug code. And so far I have personally not found any of this debug code to be *useful*.
In light of that situation, I'd like to try just ripping all of it out. If I spend any more time dealing with coverage debug code, I want it to be because I'm writing new and useful tools, not dutifully maintaining a boat-anchor that quite plausibly isn't being used by anyone at all.
---
r? `@ghost`
`@rustbot` label +A-code-coverage
---
[Zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Removing.20debug.20code.20from.20the.20coverage.20instrumentor)
clean up unneeded `ToPredicate` impls
Part of #107250.
Removed all totally unused impls. And inlined two impls not need to satisify trait bound.
r? `@oli-obk`
miri: reduce code duplication in some SSE/SSE2 intrinsics
Reduces code duplication in the Miri implementation of some SSE and SSE2 using generics and rustc_const_eval helper functions.
There are also some other minor changes.
r? `@RalfJung`
fix confusing let chain indentation in rustc_resolve
Sorry for opening a PR for such a minor style fix.
This just felt sufficiently misleading to warrant fixing.
Correctly deny late-bound lifetimes from parent in anon consts and TAITs
Reuse the `AnonConstBoundary` scope (introduced in #108553, renamed in this PR to `LateBoundary`) to deny late-bound vars of *all* kinds (ty/const/lifetime) in anon consts and TAITs.
Side-note, but I would like to consolidate this with the error reporting for RPITs (E0657):
c4f25777a0/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs (L733-L754) but the semantics about what we're allowed to capture there are slightly different, so I'm leaving that untouched.
Fixes#115474
Pretty-print argument-position impl trait to name it.
This removes a corner case.
RPIT and TAIT keep having no name, and it would be wrong to use the one in HIR (Ident::empty), so I make this case ICE.
Detect cycle errors hidden by opaques during monomorphization
Opaque types may reveal to projections, which themselves normalize to opaques. We don't currently normalize when checking that opaques are cyclical, and we may also not know that the opaque is cyclical until monomorphization (see `tests/ui/type-alias-impl-trait/mututally-recursive-overflow.rs`).
Detect cycle errors in `normalize_projection_ty` and report a fatal overflow (in the old solver). Luckily, this is already detected as a fatal overflow in the new solver.
Fixes#112047
rustc_target/riscv: Fix passing of transparent unions with only one non-ZST member
This ensures that `MaybeUninit<T>` has the same ABI as `T` when passed through an `extern "C"` function.
Fixes https://github.com/rust-lang/rust/issues/115481.
r? `@RalfJung`
Don't modify libstd to dump rustc ICEs
Do a much simpler thing and just dump a `std::backtrace::Backtrace` to file.
r? `@estebank` `@oli-obk`
Fixes#115610
move things out of mir/mod.rs
This moves a bunch of things out of `mir/mod.rs`:
- all const-related stuff to a new file consts.rs
- all statement/place/operand-related stuff to a new file statement.rs
- all pretty-printing related stuff to pretty.rs
`mod.rs` started out with 3100 lines and ends up with 1600. :)
Also there was some pretty-printing stuff in terminator.rs, that also got moved to pretty.rs, and I reordered things in pretty.rs so that it can be grouped by functionality.
Only the commit "use pretty_print_const_value from MIR constant 'extra' printing" has any behavior changes; it resolves the issue of having a fancy and a very crude pretty-printer for `ConstValue`.
r? `@oli-obk`
Don't complain on a single non-exhaustive 1-ZST
r? RalfJung, though you mentioned being busy, so feel free to reassign.
This doesn't actually attempt to make the diagnostic better, so when we have two non-exhaustive 1-ZSTs in a struct, we still just point to one. 🤷Fixes#115922
Explain HRTB + infer limitations of old solver
Add a helpful message when we hit the limitation of the old trait solver where we don't properly normalize GATs with infer vars + bound vars, leading to too-eagerly reporting trait errors that would be later satisfied due to inference.
Don't resolve generic impls that may be shadowed by dyn built-in impls
**NOTE:** This is a hack. This is not trying to be a general fix for the issue that we've allowed overlapping built-in trait object impls and user-written impls for quite a long time, and traits like `Any` rely on this (#57893) -- this PR specifically aims to mitigate a new unsoundness that is uncovered by the MIR inliner (#114928) that interacts with this pre-existing issue.
Builtin `dyn Trait` impls may overlap with user-provided blanket impls (`impl<T: ?Sized> Trait for T`) in generic contexts. This leads to bugs when instances are resolved in polymorphic contexts, since we typically prefer object candidates over impl candidates.
This PR implements a (hacky) heuristic to `resolve_associated_item` to account for that unfortunate hole in the type system -- we now bail with ambiguity if we try to resolve a non-rigid instance whose self type is not known to be sized. This makes sure we can still inline instances like `impl<T: Sized> Trait for T`, which can never overlap with `dyn Trait`'s built-in impl, but we avoid inlining an impl that may be shadowed by a `dyn Trait`.
Fixes#114928
Enable ASAN/LSAN/TSAN for *-apple-ios-macabi
The -macabi targets are iOS running on MacOS, and they use the runtime libraries for MacOS, thus they have the same sanitizers available as the *-apple-darwin targets.
This is based on the work of aacf3213b1.
Closes#113935.
coverage: Fix an unstable-sort inconsistency in coverage spans
This code was calling `sort_unstable_by`, but failed to impose a total order on the initial spans. That resulted in unpredictable handling of closure spans, producing inconsistencies in the coverage maps and in user-visible coverage reports.
This PR fixes the problem by always sorting closure spans before otherwise-identical non-closure spans, and also switches to a stable sort in case the ordering is still not total.
---
In addition to the fix itself, this PR also contains a cleanup to the comparison function that I was working on when I discovered the bug.
Make `TyKind::Adt`'s `Debug` impl be more pretty
Currently `{:?}` on `Ty` for a `TyKind::Adt` would print as `Adt(Foo, [])`. This PR changes it to be `Foo` when there are no generics or `Foo<T>`/`Foo<T, U>` when there _are_ generics. Example from debug log:
`├─0ms DEBUG rustc_hir_analysis::astconv return=Bar<T/#0, U/#1>`
I should have done this in my initial PR for a prettier TyKind: Debug impl but I thought I would need to be accessing generics_of to figure out where in the "path" the generics would have to go??? but no, adts literally only have a single place the generics can go (on the end). Feel a bit silly about this :)
r? `@oli-obk`
Avoid blessing cargo deps's source code in ui tests
Before this PR, the source code of dependencies was included in UI test error messages whenever possible. Unfortunately, "whenever possible" means in some cases the source code wouldn't be injected, resulting in a test failure.
One such case is when `$CARGO_HOME` is remapped to something that is not present on disk [^1]. As the remapped path doesn't exist on disk, the source code wouldn't be showed in `tests/ui/issues/issue-21763.rs`:
```diff
= note: required for `hashbrown::raw::RawTable<(Rc<()>, Rc<()>)>` to implement `Send`
note: required because it appears within the type `HashMap<Rc<()>, Rc<()>, RandomState>`
--> $HASHBROWN_SRC_LOCATION
- |
-LL | pub struct HashMap<K, V, S = DefaultHashBuilder, A: Allocator + Clone = Global> {
- | ^^^^^^^
note: required because it appears within the type `HashMap<Rc<()>, Rc<()>>`
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
note: required by a bound in `foo`
```
This PR fixes the problem by always hiding dependencies source code in the error messages generated during UI tests. This is implemented with a new internal flag, `-Z ignore-directory-in-diagnostics-source-blocks=$path`, which compiletest passes during UI tests. Once this is merged, remapping the Cargo home will be supported.
This PR is best reviewed commit-by-commit.
[^1]: After being puzzled for a bit, I discovered why this never impacted `rust-lang/rust`: we don't remap `$CARGO_HOME` 😅. Instead, we set `$CARGO_HOME` to `/cargo` in CI, which sort-of-but-not-really achieves the same effect.
