assert more in release in `rustc_ast_lowering`
My understanding of the compiler's architecture is that in the `ast_lowering` crate, we are constructing the HIR as a one-time thing per crate. This is after tokenizing, parsing, resolution, expansion, possible reparsing, reresolution, reexpansion, and so on. In other words, there are many reasons that perf-focused PRs spend a lot of time touching `rustc_parse`, `rustc_expand`, `rustc_ast`, and then `rustc_hir` and "onwards", but `ast_lowering` is a little bit of an odd duck.
In this crate, we have a number of debug assertions. Some are clearly expensive checks that seem like they are prohibitive to run in actual optimized compiler builds, but then there are a number that are simple asserts on integer equalities, `is_empty`, or the like. I believe we should do some of them even in release builds, because the correctness gain is worth the performance cost: almost zero.
add `extern "custom"` functions
tracking issue: rust-lang/rust#140829
previous discussion: https://github.com/rust-lang/rust/issues/140566
In short, an `extern "custom"` function is a function with a custom ABI, that rust does not know about. Therefore, such functions can only be defined with `#[unsafe(naked)]` and `naked_asm!`, or via an `extern "C" { /* ... */ }` block. These functions cannot be called using normal rust syntax: calling them can only be done from inline assembly.
The motivation is low-level scenarios where a custom calling convention is used. Currently, we often pick `extern "C"`, but that is a lie because the function does not actually respect the C calling convention.
At the moment `"custom"` seems to be the name with the most support. That name is not final, but we need to pick something to actually implement this.
r? `@traviscross`
cc `@tgross35`
try-job: x86_64-apple-2
Replace some `Option<Span>` with `Span` and use DUMMY_SP instead of None
Turns out many locations actually have a span available that we could use, so I used it
Add a new `mismatched-lifetime-syntaxes` lint
The lang-team [discussed this](https://hackmd.io/nf4ZUYd7Rp6rq-1svJZSaQ) and I attempted to [summarize](https://github.com/rust-lang/rust/pull/120808#issuecomment-2701863833) their decision. The summary-of-the-summary is:
- Using two different kinds of syntax for elided lifetimes is confusing. In rare cases, it may even [lead to unsound code](https://github.com/rust-lang/rust/issues/48686)! Some examples:
```rust
// Lint will warn about these
fn(v: ContainsLifetime) -> ContainsLifetime<'_>;
fn(&'static u8) -> &u8;
```
- Matching up references with no lifetime syntax, references with anonymous lifetime syntax, and paths with anonymous lifetime syntax is an exception to the simplest possible rule:
```rust
// Lint will not warn about these
fn(&u8) -> &'_ u8;
fn(&'_ u8) -> &u8;
fn(&u8) -> ContainsLifetime<'_>;
```
- Having a lint for consistent syntax of elided lifetimes will make the [future goal](https://github.com/rust-lang/rust/issues/91639) of warning-by-default for paths participating in elision much simpler.
---
This new lint attempts to accomplish the goal of enforcing consistent syntax. In the process, it supersedes and replaces the existing `elided-named-lifetimes` lint, which means it starts out life as warn-by-default.
This adds an `iter!` macro that can be used to create movable
generators.
This also adds a yield_expr feature so the `yield` keyword can be used
within iter! macro bodies. This was needed because several unstable
features each need `yield` expressions, so this allows us to stabilize
them separately from any individual feature.
Co-authored-by: Oli Scherer <github35764891676564198441@oli-obk.de>
Co-authored-by: Jieyou Xu <jieyouxu@outlook.com>
Co-authored-by: Travis Cross <tc@traviscross.com>
Rollup of 9 pull requests
Successful merges:
- rust-lang/rust#141554 (Improve documentation for codegen options)
- rust-lang/rust#141817 (rustc_llvm: add Windows system libs only when cross-compiling from Wi…)
- rust-lang/rust#141843 (Add `visit_id` to ast `Visitor`)
- rust-lang/rust#141881 (Subtree update of `rust-analyzer`)
- rust-lang/rust#141898 ([rustdoc-json] Implement PartialOrd and Ord for rustdoc_types::Id)
- rust-lang/rust#141921 (Disable f64 minimum/maximum tests for arm 32)
- rust-lang/rust#141930 (Enable triagebot `[concern]` functionality)
- rust-lang/rust#141936 (Decouple "reporting in deps" from `FutureIncompatibilityReason`)
- rust-lang/rust#141949 (move `test-float-parse` tool into `src/tools` dir)
r? `@ghost`
`@rustbot` modify labels: rollup
Add `visit_id` to ast `Visitor`
This helps with efforts to deduplicate the `MutVisitor` and the `Visitor` code. All users of `Visitor`'s methods that have extra `NodeId` as parameters really just want to visit the id on its own.
Also includes some methods deduplicated and cleaned up as a result of this change.
r? oli-obk
`UsePath` contains a `SmallVec<[Res; 3]>`. This holds up to three `Res`
results, one per namespace (type, value, or macro). `lower_import_res`
takes a `PerNS<Option<Res<NodeId>>>` result and lowers it into the
`SmallVec`. This is pretty weird. The input `PerNS` makes it clear which
`Res` belongs to which namespace, but the `SmallVec` throws that
information away.
And code that operates on the `SmallVec` tends to use iteration (or even
just grabbing the first entry!) without knowing which namespace the
`Res` belongs to. Even weirder! Also, `SmallVec` is an overly flexible
type to use here, because it can contain any number of elements (even
though it's optimized for 3 in this case).
This commit changes `UsePath` so it also contains a
`PerNS<Option<Res<HirId>>>`. This type preserves more information and is
more self-documenting. The commit also changes a lot of the use sites to
access the result for a particular namespace. E.g. if you're looking up
a trait, it will be in the `Res` for the type namespace if it's present;
it's silly to look in the `Res` for the value namespace or macro
namespace. Overall I find the new code much easier to understand.
However, some use sites still iterate. These now use `present_items`
because that filters out the `None` results.
Also, `redundant_pub_crate.rs` gets a bigger change. A
`UseKind:ListStem` item gets no `Res` results, which means the old `all`
call in `is_not_macro_export` would succeed (because `all` succeeds on
an empty iterator) and the `ListStem` would be ignored. This is what we
want, but was more by luck than design. The new code detects `ListStem`
explicitly. The commit generalizes the name of that function
accordingly.
Finally, the commit also removes the `use_path` arena, because
`PerNS<Option<Res>>` impls `Copy` (unlike `SmallVec`) and it can be
allocated in the arena shared by all `Copy` types.
This helps with efforts to deduplicate the `MutVisitor` and the
`Visitor` code. All users of `Visitor`'s methods that have extra
`NodeId` as parameters really just want to visit the id on its
own.
Also includes some methods deduplicated and cleaned up as
a result of this change.
Specifically `TyAlias`, `Enum`, `Struct`, `Union`. So the fields match
the textual order in the source code.
The interesting part of the change is in
`compiler/rustc_hir/src/hir.rs`. The rest is extremely mechanical
refactoring.
So they match the order of the parts in the source code, e.g.:
```
struct Foo<T, U> { t: T, u: U }
<-><----> <------------>
/ | \
ident generics variant_data
```
Stage0 bootstrap update
This PR [follows the release process](https://forge.rust-lang.org/release/process.html#master-bootstrap-update-tuesday) to update the stage0 compiler.
The only thing of note is 58651d1b31, which was flagged by clippy as a correctness fix. I think allowing that lint in our case makes sense, but it's worth to have a second pair of eyes on it.
r? `@Mark-Simulacrum`
Remove global `next_disambiguator` state and handle it with a `DisambiguatorState` type
This removes `Definitions.next_disambiguator` as it doesn't guarantee deterministic def paths when `create_def` is called in parallel. Instead a new `DisambiguatorState` type is passed as a mutable reference to `create_def` to help create unique def paths. `create_def` calls with distinct `DisambiguatorState` instances must ensure that that the def paths are unique without its help.
Anon associated types did rely on this global state for uniqueness and are changed to use (method they're defined in + their position in the method return type) as the `DefPathData` to ensure uniqueness. This also means that the method they're defined in appears in error messages, which is nicer.
`DefPathData::NestedStatic` is added to use for nested data inside statics instead of reusing `DefPathData::AnonConst` to avoid conflicts with those.
cc `@oli-obk`
Drop AST on a separate thread and prefetch `hir_crate`
This drop AST on a separate thread and prefetches `hir_crate`.
A `spawn` function is added to the `parallel` module which spawn some work on the Rayon thread pool.
Rollup of 8 pull requests
Successful merges:
- #137653 (Deprecate the unstable `concat_idents!`)
- #138957 (Update the index of Option to make the summary more comprehensive)
- #140006 (ensure compiler existance of tools on the dist step)
- #140143 (Move `sys::pal::os::Env` into `sys::env`)
- #140202 (Make #![feature(let_chains)] bootstrap conditional in compiler/)
- #140236 (norm nested aliases before evaluating the parent goal)
- #140257 (Some drive-by housecleaning in `rustc_borrowck`)
- #140278 (Don't use item name to look up associated item from trait item)
r? `@ghost`
`@rustbot` modify labels: rollup
Make #![feature(let_chains)] bootstrap conditional in compiler/
Let chains have been stabilized recently in #132833, so we can remove the gating from our uses in the compiler (as the compiler uses edition 2024).
An upcoming lint will want to be able to know if a lifetime is
hidden (e.g. `&u8`, `ContainsLifetime`) or anonymous: (e.g. `&'_ u8`,
`ContainsLifetime<'_>`). It will also want to know if the lifetime is
related to a reference (`&u8`) or a path (`ContainsLifetime`).
I'm removing empty identifiers everywhere, because in practice they
always mean "no identifier" rather than "empty identifier". (An empty
identifier is impossible.) It's better to use `Option` to mean "no
identifier" because you then can't forget about the "no identifier"
possibility.
Some specifics:
- When testing an attribute for a single name, the commit uses the
`has_name` method.
- When testing an attribute for multiple names, the commit uses the new
`has_any_name` method.
- When using `match` on an attribute, the match arms now have `Some` on
them.
In the tests, we now avoid printing empty identifiers by not printing
the identifier in the `error:` line at all, instead letting the carets
point out the problem.
Rename `LifetimeName` as `LifetimeKind`.
It's a much better name, more consistent with how we name such things.
Also rename `Lifetime::res` as `Lifetime::kind` to match. I suspect this field used to have the type `LifetimeRes` and then the type was changed but the field name remained the same.
r? ``@BoxyUwU``
It's a much better name, more consistent with how we name such things.
Also rename `Lifetime::res` as `Lifetime::kind` to match. I suspect this
field used to have the type `LifetimeRes` and then the type was changed
but the field name remained the same.
