The Rust LoongArch targets have been using the default LLVM code model
so far, which is "small" in LLVM-speak and "normal" in LoongArch-speak.
As described in the "Code Model" section of LoongArch ELF psABI spec
v20231219 [1], one can only make function calls as far as ±128MiB with
the "normal" code model; this is insufficient for very large software
containing Rust components that needs to be linked into the big text
section, such as Chromium.
Because:
* we do not want to ask users to recompile std if they are to build
such software,
* objects compiled with larger code models can be linked with those
with smaller code models without problems, and
* the "medium" code model is comparable to the "small"/"normal" one
performance-wise (same data access pattern; each function call
becomes 2-insn long and indirect, but this may be relaxed back into
the direct 1-insn form in a future LLVM version), but is able to
perform function calls within ±128GiB,
it is better to just switch the targets to the "medium" code model,
which is also "medium" in LLVM-speak.
[1]: https://github.com/loongson/la-abi-specs/blob/v2.30/laelf.adoc#code-models
coverage: Improve handling of function/closure spans
This is a combination of some loosely-related changes that touch the same code:
1. Make unexpansion of closure bodies more precise, by unexpanding back to the context of the closure declaration, instead of unexpanding all the way back to the top-level context. This preserves the way we handle async desugaring and closures containing a single bang-macro, while also giving better results for closures defined in macros.
2. Skip the normal span-refinement code when dealing with the trivial outer part of an async function.
3. Be more explicit about the fact that `fn_sig_span` has been extended to the start of the function body, and is not necessarily present.
---
`@rustbot` label +A-code-coverage
Move predicate, region, and const stuff into their own modules in middle
This PR mostly moves things around, and in a few cases adds some `ty::` to the beginning of names to avoid one-off imports.
I don't mean this to be the most *thorough* move/refactor. I just generally wanted to begin to split up `ty/mod.rs` and `ty/sty.rs` which are huge and hard to distinguish, and have a lot of non-ty stuff in them.
r? lcnr
This sidesteps the normal span refinement code in cases where we know that we
are only dealing with the special signature span that represents having called
an async function.
The two kinds of delayed bug have quite different semantics so a
stronger conceptual separation is nice. (`is_error` is a good example,
because the two kinds have different behaviour.)
The commit also moves the `DelayedBug` variant after `Error` in `Level`,
to reflect the fact that it's weaker than `Error` -- it might trigger an
error but also might not. (The pre-existing `downgrade_to_delayed_bug`
function also reflects the notion that delayed bugs are lower/after
normal errors.)
Plus it condenses some of the comments on `Level` into a table, for
easier reading, and introduces `can_be_top_or_sub` to indicate which
levels can be used in top-level diagnostics vs. subdiagnostics.
Finally, it renames `DiagCtxtInner::span_delayed_bugs` as
`DiagCtxtInner::delayed_bugs`. The `span_` prefix is unnecessary because
some delayed bugs don't have a span.
- Combine two different blocks involving
`diagnostic.level.get_expectation_id()` into one.
- Combine several `if`s involving `diagnostic.level` into a single
`match`.
This requires reordering some of the operations, but this has no
functional effect.
Rollup of 8 pull requests
Successful merges:
- #119759 (Add FileCheck annotations to dataflow-const-prop tests)
- #120323 (On E0277 be clearer about implicit `Sized` bounds on type params and assoc types)
- #120473 (Only suggest removal of `as_*` and `to_` conversion methods on E0308)
- #120540 (add test for try-block-in-match-arm)
- #120547 (`#![feature(inline_const_pat)]` is no longer incomplete)
- #120552 (Correctly check `never_type` feature gating)
- #120555 (put pnkfelix (me) back on the review queue.)
- #120556 (Improve the diagnostics for unused generic parameters)
r? `@ghost`
`@rustbot` modify labels: rollup
It doesn't affect behaviour, but makes sense with (a) `FailureNote` having
`()` as its emission guarantee, and (b) in `Level` the `is_error` levels
now are all listed before the non-`is_error` levels.
Rollup of 8 pull requests
Successful merges:
- #120484 (Avoid ICE when is_val_statically_known is not of a supported type)
- #120516 (pattern_analysis: cleanup manual impls)
- #120517 (never patterns: It is correct to lower `!` to `_`.)
- #120523 (Improve `io::Read::read_buf_exact` error case)
- #120528 (Store SHOULD_CAPTURE as AtomicU8)
- #120529 (Update data layouts in custom target tests for LLVM 18)
- #120531 (Remove a bunch of `has_errors` checks that have no meaningful or the wrong effect)
- #120533 (Correct paths for hexagon-unknown-none-elf platform doc)
r? `@ghost`
`@rustbot` modify labels: rollup
Improve the diagnostics for unused generic parameters
* Don't emit two errors (namely E0091 *and* E0392) for unused type parameters on *lazy* type aliases
* Fix the diagnostic help message of E0392 for *lazy* type aliases: Don't talk about the “fields” of lazy type aliases (use the term “body” instead) and don't suggest `PhantomData` for them, it doesn't make much sense
* Consolidate the diagnostics for E0091 (unused type parameters in type aliases) and E0392 (unused generic parameters due to bivariance) and make it translatable
* Still keep the error codes distinct (for now)
* Naturally leads to better diagnostics for E0091
r? ```@oli-obk``` (to ballast your review load :P) or compiler
Correctly check `never_type` feature gating
Fixes#120542.
The feature wasn't tested on return type of a generic function type, so it got under the radar in https://github.com/rust-lang/rust/pull/120316.
r? ```@compiler-errors```
`#![feature(inline_const_pat)]` is no longer incomplete
Now that borrow checking and safety checking is implemented for inline constant patterns, the incomplete feature status is not necessary. Stabilizing this feature requires more testing and has some of the same unresolved questions as inline constants.
cc #76001
it works when a non-const context that does not enable effects
calls into a const effects-enabled trait. We'd simply suggest the
non-const trait bound in this case consistent to its fallback.
never patterns: It is correct to lower `!` to `_`.
This is just a comment update but a non-trivial one: it is correct to lower `!` patterns as `_`. The reasoning is that `!` matches all the possible values of the type, since the type is empty. Moreover, we do want to warn that the `Err` is redundant in:
```rust
match x {
!,
Err(!),
}
```
which is consistent with `!` behaving like a wildcard.
I did try to introduce `Constructor::Never` and it ended up needing to behave exactly like `Constructor::Wildcard`.
r? ```@compiler-errors```
Avoid ICE when is_val_statically_known is not of a supported type
2 ICE with 1 stone!
1. Implement `llvm.is.constant.ptr` to avoid first ICE in linked issue.
2. return `false` when the argument is not one of `i*`/`f*`/`ptr` to avoid second ICE.
fixes#120480
hir: Remove the generic type parameter from `MaybeOwned`
It's only ever used with a reference to `OwnerInfo` as an argument.
Follow up to https://github.com/rust-lang/rust/pull/120346.
Remove `BorrowckErrors::tainted_by_errors`
This PR removes one of the `tainted_by_errors` occurrences, replacing it with direct use of `ErrorGuaranteed`.
r? `@oli-obk`
Suggest changing type to const parameters if we encounter a type in the trait bound position
The first commit is just drive-by cleanup.
Provide a structured suggestion if the user forgot to prefix a “const parameter” with `const`, e.g., in `struct Tagged<TAG: u64>;`. This happens to me from time to time. Maybe C++ devs are also prone to this mistake given template syntax looks like `template<typename T, uint32_t N>`.
`emit_future_breakage` calls
`self.dcx().take_future_breakage_diagnostics()` and then passes the
result to `self.dcx().emit_future_breakage_report(diags)`. This commit
removes the first of these and lets `emit_future_breakage_report` do the
taking.
It also inlines and removes what is left of `emit_future_breakage`,
which has a single call site.
- `emitted_at` isn't used outside the crate.
- `code` and `messages` are public fields, so there's no point have
trivial getters/setters for them.
- `suggestions` is public, so the comment about "functionality on
`Diagnostic`" isn't needed.
