Add `#[loop_match]` for improved DFA codegen
tracking issue: https://github.com/rust-lang/rust/issues/132306
project goal: https://github.com/rust-lang/rust-project-goals/issues/258
This PR adds the `#[loop_match]` attribute, which aims to improve code generation for state machines. For some (very exciting) benchmarks, see https://github.com/rust-lang/rust-project-goals/issues/258#issuecomment-2732965199
Currently, a very restricted syntax pattern is accepted. We'd like to get feedback and merge this now before we go too far in a direction that others have concerns with.
## current state
We accept code that looks like this
```rust
#[loop_match]
loop {
state = 'blk: {
match state {
State::A => {
#[const_continue]
break 'blk State::B
}
State::B => { /* ... */ }
/* ... */
}
}
}
```
- a loop should have the same semantics with and without `#[loop_match]`: normal `continue` and `break` continue to work
- `#[const_continue]` is only allowed in loops annotated with `#[loop_match]`
- the loop body needs to have this particular shape (a single assignment to the match scrutinee, with the body a labelled block containing just a match)
## future work
- perform const evaluation on the `break` value
- support more state/scrutinee types
## maybe future work
- allow `continue 'label value` syntax, which `#[const_continue]` could then use.
- allow the match to be on an arbitrary expression (e.g. `State::Initial`)
- attempt to also optimize `break`/`continue` expressions that are not marked with `#[const_continue]`
r? ``@traviscross``
Implement parsing of pinned borrows
This PR implements part of #130494.
EDIT: It introduces `&pin mut $place` and `&pin const $place` as sugars for `std::pin::pin!($place)` and its shared reference equivalent, except that `$place` will not be moved when borrowing. The borrow check will be in charge of enforcing places cannot be moved or mutably borrowed since being pinned till dropped.
### Implementation steps:
- [x] parse the `&pin mut $place` and `&pin const $place` syntaxes
- [ ] borrowck of `&pin mut|const`
- [ ] support autoref of `&pin mut|const` when needed
update to literal-escaper 0.0.4 for better API without `unreachable` and faster string parsing
This is the replacement for just the part of https://github.com/rust-lang/rust/pull/138163 dealing with the changed API of unescape functionality, since that got moved into its own crate.
<del>This uses an unpublished version of literal-escaper (https://github.com/rust-lang/literal-escaper/pull/8).</del>
r? `@nnethercote`
update to literal-escaper 0.0.4 for better API without `unreachable` and faster string parsing
This is the replacement for just the part of https://github.com/rust-lang/rust/pull/138163 dealing with the changed API of unescape functionality, since that got moved into its own crate.
<del>This uses an unpublished version of literal-escaper (https://github.com/rust-lang/literal-escaper/pull/8).</del>
r? `@nnethercote`
This brings in a few updates to the bundled `wasm-component-ld`
dependency used by the `wasm32-wasip2` target. This primarily includes
support for upcoming component model async/WASIp3 support which will be
convenient to have native support for a few months from now.
Rollup of 9 pull requests
Successful merges:
- rust-lang/rust#142645 (Also emit suggestions for usages in the `non_upper_case_globals` lint)
- rust-lang/rust#142657 (mbe: Clean up code with non-optional `NonterminalKind`)
- rust-lang/rust#142799 (rustc_session: Add a structure for keeping both explicit and default sysroots)
- rust-lang/rust#142805 (Emit a single error when importing a path with `_`)
- rust-lang/rust#142882 (Lazy init diagnostics-only local_names in borrowck)
- rust-lang/rust#142883 (Add impl_trait_in_bindings tests from rust-lang/rust#61773)
- rust-lang/rust#142943 (Don't include current rustc version string in feature removed help)
- rust-lang/rust#142965 ([RTE-497] Ignore `c-link-to-rust-va-list-fn` test on SGX platform)
- rust-lang/rust#142972 (Add a missing mailmap entry)
r? `@ghost`
`@rustbot` modify labels: rollup
This used to be necessary for a correct linker order, but ever since the
introduction of symbols.o adding the symbols in question to symbols.o
would work just as well. We do still add dependencies on the panic runtime
to the local crate, but not for #![needs_panic_runtime] crates.
This also removes the runtime-depends-on-needs-runtime test.
inject_dependency_if used to emit this error, but with symbols.o it is
no longer important that there is no dependency and in fact it may be
nice to have panic_abort and panic_unwind directly depend on libstd in
the future for calling std::process::abort().
rustc_std_internal_symbol is meant to call functions from crates where
there is no direct dependency on said crate. As they either have to be
added to symbols.o or rustc has to introduce an implicit dependency on
them to avoid linker errors. The latter is done for some things like the
panic runtime, but adding these symbols to symbols.o allows removing
those implicit dependencies.
`cargo fix` does not have a way of distinguishing a suggestion with
multiple spans which should all be applied from multiple suggestions
where only one should be applied (see issue 53934). `cargo fix` only
works with `MachineApplicable` suggestions, so downgrading the
applicability will stop `cargo` from suggesting the user run `cargo
fix`. rust-analyzer does work with `MaybeIncorrect`, so interactive
fixes are still available.
Subtree sync for rustc_codegen_cranelift
The main highlight this time is a Cranelift update.
r? `@ghost`
`@rustbot` label +A-codegen +A-cranelift +T-compiler
[RTE-497] Ignore `c-link-to-rust-va-list-fn` test on SGX platform
rust-lang/rust#141856 enables using the runner defined in bootstrap.toml to execute run-make tests. A test was added for this feature that compiles a Rust library and C code, links them together and passes the result to the runner. Unfortunately, that's not sufficient for the SGX platform; x86 machine code cannot be directly executed. This PR fixes the issue by disabling this test for SGX.
Don't include current rustc version string in feature removed help
The version string is difficult to properly normalize out, and removing it isn't a huge deal (the user can query version info easily through `rustc --version` or `cargo --version`).
The normalization options were all non-ideal (see https://github.com/rust-lang/rust/pull/142940#issuecomment-2998518450):
- Per-test version string normalization is nasty to maintain, and we need to maintain `n` copies of it. See rust-lang/rust#142930 where the regex wasn't robust against different release channels.
- Centralized compiletest normalization (with a directive opt-out) is also not ideal, because `cfg(version(..))` tests can't have those accidentally normalized out (and you'd have to remember to opt-out).
r? `@workingjubilee` (discussed in rust-lang/rust#142940)
Lazy init diagnostics-only local_names in borrowck
`local_names` is not used during successful compilation, so not initializing it saves a little bit of work.
I've also made it accessible only from the diagnostics module to make it clearer that the names are from `var_debug_info` which is technically optional and could be absent.
Emit a single error when importing a path with `_`
When encountering `use _;`, `use _::*'` or similar, do not emit two errors for that single mistake. This also side-steps the issue of resolve errors suggesting adding a crate named `_` to `Cargo.toml`.
Fixrust-lang/rust#142662.
mbe: Clean up code with non-optional `NonterminalKind`
Since [rust-lang/rust#128425], the fragment specifier is unconditionally required in all
editions. This means `NonTerminalKind` no longer needs to be optional,
as we can reject this code during the expansion of `macro_rules!` rather
than handling it throughout the code. Do this cleanup here.
[rust-lang/rust#128425]: https://github.com/rust-lang/rust/pull/128425
Also emit suggestions for usages in the `non_upper_case_globals` lint
This PR adds suggestions for all the usages of the renamed item in the warning of the `non_upper_case_globals` lint.
Fixes https://github.com/rust-lang/rust/issues/124061
```
error[E0382]: borrow of moved value: `x`
--> $DIR/moves-based-on-type-capture-clause-bad.rs:9:20
|
LL | let x = "Hello world!".to_string();
| - move occurs because `x` has type `String`, which does not implement the `Copy` trait
LL | thread::spawn(move || {
| ------- value moved into closure here
LL | println!("{}", x);
| - variable moved due to use in closure
LL | });
LL | println!("{}", x);
| ^ value borrowed here after move
|
= note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider cloning the value before moving it into the closure
|
LL ~ let value = x.clone();
LL ~ thread::spawn(move || {
LL ~ println!("{}", value);
|
```
When encountering `use _;`, `use _::*'` or similar, do not emit two errors for that single mistake. This also side-steps the issue of resolve errors suggesting adding a crate named `_` to `Cargo.toml`.
Violets are red,
Roses are blue,
Summer’s a feeling,
And we’re feeling it too.
<hr>
> (Please ping me when June made it as the cat of the release. I want to
send it to her owner :D)
@xFrednet voila:
Cats for the next release can be traditionally nominated in the comments
:D
Please be more active and cat-minded 😻
<hr>
changelog: none
r? flip1995
The version string is difficult to properly normalize out, and removing
it isn't a huge deal (the user can query version info easily through
`rustc --version` or `cargo --version`).
The normalization options were all non-ideal:
- Per-test version string normalization is nasty to maintain, and we
need to maintain `n` copies of it.
- Centralized compiletest normalization (with a directive opt-out) is
also not ideal, because `cfg(version(..))` tests can't have those
accidentally normalized out (and you'd have to remember to opt-out).
