rustc: Some small changes for the wasm32-wasip2 target
This commit has a few changes for the wasm32-wasip2 target. The first two are aimed at improving the compatibility of using `clang` as an external linker driver on this target. The default target to LLVM is updated to match the Rust target and additionally the `-fuse-ld=lld` argument is dropped since that otherwise interferes with clang's own linker detection. The only linker on wasm targets is LLD but on the wasip2 target a wrapper around LLD, `wasm-component-ld`, is used to drive the process and perform steps necessary for componentization.
The final commit changes the output of all objects on the wasip2 target to being PIC by default. This improves compatibilty with shared libaries but notably does not mean that there's a turnkey solution for shared libraries. The hope is that by having the standard libray work both with and without dynamic libraries will make experimentation easier.
Improve `rustc_parse::Parser`'s debuggability
The main event is the final commit where I add `Parser::debug_lookahead`. Everything else was basically cleaning up things that bugged me (debugging, as it were) until I felt comfortable enough to actually work on it.
The motivation is that it's annoying as hell to try to figure out how the debug infra works in rustc without having basic queries like `debug!(?parser);` come up "empty". However, Parser has a lot of fields that are mostly irrelevant for most debugging, like the entire ParseSess. I think `Parser::debug_lookahead` with a capped lookahead might be fine as a general-purpose Debug impl, but this adapter version was suggested to allow more choice, and admittedly, it's a refined version of what I was already handrolling just to get some insight going.
I tried debugging a parser-related issue but found it annoying to not be
able to easily peek into the Parser's token stream.
Add a convenience fn that offers an opinionated view into the parser,
but one that is useful for answering basic questions about parser state.
coverage: Branch coverage support for let-else and if-let
This PR adds branch coverage instrumentation for let-else and if-let, including let-chains.
This lifts two of the limitations listed at #124118.
This commit changes the new `wasm32-wasip2` target to being PIC by
default rather than the previous non-PIC by default. This change is
intended to make it easier for the standard library to be used in a
shared object in its precompiled form. This comes with a hypothetical
modest slowdown but it's expected that this is quite minor in most use
cases or otherwise wasm compilers and/or optimizing runtimes can elide
the cost.
Do not ICE on `AnonConst`s in `diagnostic_hir_wf_check`
Fixes#122989
Below is the snippet from #122989 that ICEs:
```rust
trait Traitor<const N: N<2> = 1, const N: N<2> = N> {
fn N(&N) -> N<2> {
M
}
}
trait N<const N: Traitor<2> = 12> {}
```
The `AnonConst` that triggers the ICE is the `2` in the param `const N: N<2> = 1`. The currently existing code in `diagnostic_hir_wf_check` deals only with `AnonConst`s that are default values of some param, but the `2` is not a default value. It is just an `AnonConst` HIR node inside a `TraitRef` HIR node corresponding to `N<2>`. Therefore the existing code cannot handle it and this PR ensures that it does.
Rollup of 5 pull requests
Successful merges:
- #124738 (rustdoc: dedup search form HTML)
- #124827 (generalize hr alias: avoid unconstrainable infer vars)
- #124832 (narrow down visibilities in `rustc_parse::lexer`)
- #124842 (replace another Option<Span> by DUMMY_SP)
- #124846 (Don't ICE when we cannot eval a const to a valtree in the new solver)
r? `@ghost`
`@rustbot` modify labels: rollup
Don't ICE when we cannot eval a const to a valtree in the new solver
Use `const_eval_resolve` instead of `try_const_eval_resolve` because naming aside, the former doesn't ICE when a value can't be evaluated to a valtree.
r? lcnr
never patterns: lower never patterns to `Unreachable` in MIR
This lowers a `!` pattern to "goto Unreachable". Ideally I'd like to read from the place to make it clear that the UB is coming from an invalid value, but that's tricky so I'm leaving it for later.
r? `@compiler-errors` how do you feel about a lil bit of MIR lowering
Adjust 64-bit ARM data layouts for LLVM update
LLVM has updated data layouts to specify `Fn32` on 64-bit ARM to avoid C++ accidentally underaligning functions when trying to comply with member function ABIs.
This should only affect Rust in cases where we had a similar bug (I don't believe we have one), but our data layout must match to generate code.
As a compatibility adaptatation, if LLVM is not version 19 yet, `Fn32` gets voided from the data layout.
See llvm/llvm-project#90415
`@rustbot` label: +llvm-main
cc `@krasimirgg`
r? `@durin42`
borrowck: prepopulate opaque storage more eagerly
otherwise we ICE due to ambiguity when normalizing while computing implied bounds.
r? ``@compiler-errors``
Record impl args in the proof tree in new solver
Rather than rematching them during select.
Also use `ImplSource::Param` instead of `ImplSource::Builtin` for alias-bound candidates, so we don't ICE in `Instance::resolve`.
r? lcnr
LLVM has updated data layouts to specify `Fn32` on 64-bit ARM to avoid
C++ accidentally underaligning functions when trying to comply with
member function ABIs.
This should only affect Rust in cases where we had a similar bug (I
don't believe we have one), but our data layout must match to generate
code.
As a compatibility adaptatation, if LLVM is not version 19 yet, `Fn32`
gets voided from the data layout.
See llvm/llvm-project#90415
Don't consider candidates with no failing where clauses when refining obligation causes in new solver
Improves error messages when we have param-env candidates that don't deeply unify (i.e. after alias-bounds).
r? lcnr
Prefer lower vtable candidates in select in new solver
Also, adjust the select visitor to only winnow when the *parent* goal is `Certainty::Yes`. This means that we won't winnow in cases when we have any ambiguous inference guidance from two candidates.
r? lcnr
Improve check-cfg CLI errors with more structured diagnostics
This PR improve check-cfg CLI errors with more structured diagnostics.
In particular it now shows the statement where the error occurred, what kind lit it is, as well as pointing users to the doc for more details.
`@rustbot` label +F-check-cfg
Rollup of 3 pull requests
Successful merges:
- #124742 (Add `rustfmt` cfg to well known cfgs list)
- #124765 ([rustdoc] Fix bad color for setting cog in ayu theme)
- #124768 ([resubmission] Meta: Enable the brand new triagebot transfer command)
r? `@ghost`
`@rustbot` modify labels: rollup
Move some tests from `rustc_expand` to `rustc_parse`.
There are some test cases involving `parse` and `tokenstream` and `mut_visit` that are located in `rustc_expand`. Because it used to be the case that constructing a `ParseSess` required the involvement of `rustc_expand`. However, since #64197 merged (a long time ago) `rust_expand` no longer needs to be involved.
This commit moves the tests into `rustc_parse`. This is the optimal place for the `parse` tests. It's not ideal for the `tokenstream` and `mut_visit` tests -- they would be better in `rustc_ast` -- but they still rely on parsing, which is not available in `rustc_ast`. But `rustc_parse` is lower down in the crate graph and closer to `rustc_ast` than `rust_expand`, so it's still an improvement for them.
The exact renaming is as follows:
- rustc_expand/src/mut_visit/tests.rs -> rustc_parse/src/parser/mut_visit/tests.rs
- rustc_expand/src/tokenstream/tests.rs -> rustc_parse/src/parser/tokenstream/tests.rs
- rustc_expand/src/tests.rs + rustc_expand/src/parse/tests.rs -> compiler/rustc_parse/src/parser/tests.rs
The latter two test files are combined because there's no need for them to be separate, and having a `rustc_parse::parser::parse` module would be weird. This also means some `pub(crate)`s can be removed.
r? `@compiler-errors`
There are some test cases involving `parse` and `tokenstream` and
`mut_visit` that are located in `rustc_expand`. Because it used to be
the case that constructing a `ParseSess` required the involvement of
`rustc_expand`. However, since #64197 merged (a long time ago)
`rust_expand` no longer needs to be involved.
This commit moves the tests into `rustc_parse`. This is the optimal
place for the `parse` tests. It's not ideal for the `tokenstream` and
`mut_visit` tests -- they would be better in `rustc_ast` -- but they
still rely on parsing, which is not available in `rustc_ast`. But
`rustc_parse` is lower down in the crate graph and closer to `rustc_ast`
than `rust_expand`, so it's still an improvement for them.
The exact renaming is as follows:
- rustc_expand/src/mut_visit/tests.rs -> rustc_parse/src/parser/mut_visit/tests.rs
- rustc_expand/src/tokenstream/tests.rs -> rustc_parse/src/parser/tokenstream/tests.rs
- rustc_expand/src/tests.rs + rustc_expand/src/parse/tests.rs ->
compiler/rustc_parse/src/parser/tests.rs
The latter two test files are combined because there's no need for them
to be separate, and having a `rustc_parse::parser::parse` module would
be weird. This also means some `pub(crate)`s can be removed.
coverage: Split out MC/DC mappings from `BcbMappingKind`
These variants were added to `BcbMappingKind` as part of the [MC/DC coverage](https://en.wikipedia.org/wiki/Modified_Condition/Decision_Coverage) implementation in #123409, because that was the path-of-least-resistance for integrating them into the existing code.
However, they ultimately represent complex concepts that the enum was not intended to handle, leading to more complexity in the code that processes them. This PR therefore follows in the footsteps of #124545, and splits the MC/DC mappings out into their own dedicated vectors of structs.
After that, `BcbMappingKind` itself ends up having only one variant (`Code`), so this PR also flattens that enum into its enclosing struct, renamed to `mapping::CodeMapping`.
---
No functional changes.
This will conflict slightly with #124571, but hopefully that should be easy to resolve either way.
`@rustbot` label +A-code-coverage
Rollup of 6 pull requests
Successful merges:
- #124148 (rustdoc-search: search for references)
- #124668 (Fix bootstrap panic when build from tarball)
- #124736 (compiler: upgrade time from 0.3.34 to 0.3.36)
- #124748 (Fix unwinding on 32-bit watchOS ARM (v2))
- #124749 (Stabilize exclusive_range_pattern (v2))
- #124750 (Document That `f16` And `f128` Hardware Support is Limited (v2))
r? `@ghost`
`@rustbot` modify labels: rollup
compiler: upgrade time from 0.3.34 to 0.3.36
This ensures the version of `time` used in `rustc` includes this change: https://github.com/time-rs/time/pull/671.
This fix is a necessary prerequisite for #99969, which adds `FromIterator` implementations for `Box<str>`. Previously, `time` had an `Into::into` that resolved to the identity impl followed by a `collect::<Result<Box<_>, _>>()`. With the new FromIterator implementations for Box<str>, the Into::into resolution is ambiguous and time fails to compile. Thanks to `@dtolnay` for the analysis in https://github.com/rust-lang/rust/pull/99969#issuecomment-2001422230.
The `time` fix removes the identity `Into::into` conversion, allowing `time` to compile with the new `FromIterator` implementations. This version of `time` also matches what `cargo` recently switched to in https://github.com/rust-lang/cargo/pull/13834.
Remove suggestion about iteration count in coerce
Fixes#122561
The iteration count-centric suggestion was implemented in PR #100094, but it was based on the wrong assumption that the type mismatch error depends on the number of times the loop iterates. As it turns out, that is not true (see this comment for details: https://github.com/rust-lang/rust/pull/122679#issuecomment-2017432531)
This PR attempts to remedy the situation by changing the suggestion from the one centered on iteration count to a simple suggestion to add a return value.
It should also fix#100285 by simply making it redundant.
This ensures the version of time used in rustc includes this change:
https://github.com/time-rs/time/pull/671.
This fix is a necessary prerequisite for #99969,
which adds FromIterator implementations for Box<str>.
Previously, time had an Into::into that resolved to the identity impl
followed by a collect::<Result<Box<_>, _>>().
With the new FromIterator implementations for Box<str>,
the Into::into resolution is ambiguous and time fails to compile.
The fix removes the identity Into::into conversion,
allowing time to compile with the new FromIterator implementations.
This version of time also matches what cargo recently switched to
in https://github.com/rust-lang/cargo/pull/13834.
Stop `llvm.expect`ing assert terminators
We're putting `llvm.expect` calls before the <https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/enum.TerminatorKind.html#variant.Assert> terminators.
But we don't need them. One of the arms is always to a panic function that's marked `#[cold]`, which is `cold` <https://llvm.org/docs/LangRef.html#function-attributes> in LLVM, which
> When computing edge weights, basic blocks post-dominated by a cold function call are also considered to be cold; and, thus, given low weight.
So even without us emitting the extra intrinsic call, LLVM knows what to expect for the `br`. Thus we can save the (small) effort of emitting it and then LLVM optimizing it out.
r? compiler
