The MBE parser checks rules at initial parse time to see if their RHS
has `compile_error!` in it, and returns a list of rule indexes and LHS
spans that don't map to `compile_error!`, for use in unused macro rule
checking.
Instead, have the unused macro rule reporting ask the macro for the rule
to report, and let the macro check at that time. That avoids checking
rules unless they're unused.
In the process, refactor the data structure used to store macro rules,
to group the LHS and RHS (and LHS span) of each rule together, and
refactor the unused rule tracking to only track rule indexes.
This ends up being a net simplification, and reduction in code size.
The parser repeatedly invokes the `parse` function, constructing a
one-entry vector, and assuming that the return value will be a one-entry
vector. Add a helper for that case. This will simplify adding additional
callers, and put all the logic in one place to allow potential future
simplification of the one-TT case.
Stop using `Key` trait unnecessarily
Few places where the `Key` trait was being used but not really for a useful reason. This fixes those usages.
Namely, `<Ty as Key>::default_span()` is `DUMMY_SP` anyways.
Canonicalize input ty/ct infer/placeholder in the root universe
We shouldn't care what universe the inputs are, since we only ever do the leak check on the universes instantiated after entering the canonical binder.
This PR does 2 things:
- It removes the braces when there's a single element. This is required since brace expansion (at
least in bash and zsh) only triggers if there's at least 2 elements.
- It removes the extra `.rlib` suffixes of the elements. See
https://github.com/rust-lang/rust/pull/135707#discussion_r2185212393 for context.
Running `cargo +stage1 build` on the following program:
```rust
unsafe extern "C" {
fn foo() -> libc::c_int;
}
fn main() {
let x = unsafe { foo() } as u32;
// println!("{}", data_encoding::BASE64.encode(&x.to_le_bytes()));
}
```
Gives the following diff before and after the PR:
```diff
-/tmp/foo/target/debug/deps/{liblibc-faf416f178830595.rlib}.rlib
+/tmp/foo/target/debug/deps/liblibc-faf416f178830595.rlib
```
Running on the same program with the additional dependency, we get the following diff:
```diff
-/tmp/foo/target/debug/deps/{liblibc-faf416f178830595.rlib,libdata_encoding-84bb5aadfa9e8839.rlib}.rlib
+/tmp/foo/target/debug/deps/{liblibc-faf416f178830595,libdata_encoding-84bb5aadfa9e8839}.rlib
```
Do we want to add a UI test?
Remove `Symbol` from `Named` variant of `BoundRegionKind`/`LateParamRegionKind`
The `Symbol` is redundant, since we already store a `DefId` in the region variant. Instead, load the name via `item_name` when needed (which is almost always on the diagnostic path).
This introduces a `BoundRegionKind::NamedAnon` which is used for giving anonymous bound regions names, but which should only be used during pretty printing and error reporting.
Allow `enum` and `union` literals to also create SSA values
Today, `Some(x)` always goes through an `alloca`, even in trivial cases where the niching means the constructor doesn't even change the value.
For example, <https://rust.godbolt.org/z/6KG6PqoYz>
```rust
pub fn demo(r: &i32) -> Option<&i32> {
Some(r)
}
```
currently emits the IR
```llvm
define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr {
start:
%_0 = alloca [8 x i8], align 8
store ptr %r, ptr %_0, align 8
%0 = load ptr, ptr %_0, align 8
ret ptr %0
}
```
but with this PR it becomes just
```llvm
define align 4 ptr `@demo(ptr` align 4 %r) unnamed_addr {
start:
ret ptr %r
}
```
(Of course the optimizer can clean that up, but it'd be nice if it didn't have to -- especially in debug where it doesn't run. This is like rust-lang/rust#123886, but that only handled non-simd `struct`s -- this PR generalizes it to all non-simd ADTs.)
Doing this means handing variants other than `FIRST_VARIANT`, handling the active field for unions, refactoring the discriminant code so the Place and Operand parts can share the calculation, etc.
Other PRs that led up to this one:
- https://github.com/rust-lang/rust/pull/142005
- https://github.com/rust-lang/rust/pull/142103
- https://github.com/rust-lang/rust/pull/142324
- https://github.com/rust-lang/rust/pull/142383
---
try-job: aarch64-gnu
remove special-casing of boxes from match exhaustiveness/usefulness analysis
As a first step in replacing `box_patterns` with `deref_patterns`, this treats box patterns as deref patterns in the THIR and exhaustiveness analysis. This allows a bunch of special-casing to be removed. The emitted MIR is unchanged.
Incidentally, this fixes a bug caused by box patterns being treated like structs rather than pointers, where enabling `exhaustive_patterns` (rust-lang/rust#51085) could give rise to spurious `unreachable_patterns` lints on arms required for exhaustiveness. Following the lint's advice to remove the match arm would result in an error. I'm not sure what the current state of `exhaustive_patterns` is with regard to reference/box opsem, or whether there's any intention to have `unreachable_patterns` be more granular than the whole arm, but regardless this should hopefully make them easier to handle consistently.
Tracking issue for deref patterns: rust-lang/rust#87121
r? `@Nadrieril`
Make metadata a workproduct and reuse it
This PR aims to skip the generation of metadata by reusing the infrastructure that already exists for compiled codegen-units, namely "workproducts".
This can yield substantial gains (~10%) when we can demonstrate that metadata does not change between an incremental session and the next. This is the case if the crate is unchanged, or if all the changes are in upstream crates and have no effect on it. This latter case is most interesting, as it arises regularly for users with several crates in their workspace.
TODO:
- [x] Materialize the fact that metadata encoding relies on the relative order of definitions;
- [x] Refactor the handling of doc links.
Make __rust_alloc_error_handler_should_panic a function
Fixesrust-lang/rust#143253
`__rust_alloc_error_handler_should_panic` is a static but was being exported as a function.
For most targets this doesn't matter, but Arm64EC Windows uses different decorations for exported variables vs functions, hence it fails to link when `-Z oom=abort` is enabled.
We've had issues in the past with statics like this (see rust-lang/rust#141061) but the tldr; is that Arm64EC needs symbols correctly exported as either a function or data, and data MUST and MUST ONLY be marked `dllimport` when the symbol is being imported from another binary, which is non-trivial to calculate for these compiler-generated statics.
So, instead, the easiest thing to do is to make `__rust_alloc_error_handler_should_panic` a function instead.
Since `__rust_alloc_error_handler_should_panic` isn't involved in any linking shenanigans, I've marked it as `AlwaysInline` with the hopes that the various backends will see that it is just returning a constant and perform the same optimizations as the previous implementation.
r? `@bjorn3`
Make -Ztrack-diagnostics emit like a note
[#t-compiler/diagnostics > Rendering -Ztrack-diagnostics like a note](https://rust-lang.zulipchat.com/#narrow/channel/147480-t-compiler.2Fdiagnostics/topic/Rendering.20-Ztrack-diagnostics.20like.20a.20note/with/526608647)
As discussed on the Zulip thread above, I want to make `-Ztrack-diagnostics` emit like a `note`. This is because I find its current output jarring, and the fact that it gets rendered completely left-aligned, [even in the middle of a snippet](86e05cd300/tests/ui/track-diagnostics/track6.stderr), seems like something that should be changed. Turning it into a `note` seems like the best choice, as it would align it with the rest of the output, and `note` is already used for somewhat similar things, like seeing why a lint was fired.
---
Note: turning `-Ztrack-diagnostics` into a `note` will also make `annotate-snippets` API a bit cleaner
Refactor StableMIR
This PR refactors stable-mir according to the guidance in [this doc](https://hackmd.io/jBRkZLqAQL2EVgwIIeNMHg). It reverses the dependency between `rustc_smir` and `stable_mir`, making `rustc_smir` completely agnostic of `stable_mir`.
Under the new architecture, the `rustc_smir` crate would retain direct access to rustc queries, while `stable_mir` should proxy all such requests through `rustc_smir` instead of accessing rustc's internals directly. `stable_mir` would only be responsible for the conversion between internal and stable constructs.
This PR mainly introduces these changes:
- **Bridge / Tables<'tcx, B: Bridge>**
```rust
/// A trait defining types that are used to emulate StableMIR components, which is really
/// useful when programming in stable_mir-agnostic settings.
pub trait Bridge {
type DefId: Copy + Debug + PartialEq + IndexedVal;
type AllocId: Copy + Debug + PartialEq + IndexedVal;
type Span: Copy + Debug + PartialEq + IndexedVal;
type Ty: Copy + Debug + PartialEq + IndexedVal;
type InstanceDef: Copy + Debug + PartialEq + IndexedVal;
type TyConstId: Copy + Debug + PartialEq + IndexedVal;
type MirConstId: Copy + Debug + PartialEq + IndexedVal;
type Layout: Copy + Debug + PartialEq + IndexedVal;
type Error: SmirError;
}
pub struct Tables<'tcx, B: Bridge> {
tcx: TyCtxt<'tcx>,
pub(crate) def_ids: IndexMap<DefId, B::DefId>,
pub(crate) alloc_ids: IndexMap<AllocId, B::AllocId>,
pub(crate) spans: IndexMap<rustc_span::Span, B::Span>,
pub(crate) types: IndexMap<Ty<'tcx>, B::Ty>,
pub(crate) instances: IndexMap<ty::Instance<'tcx>, B::InstanceDef>,
pub(crate) ty_consts: IndexMap<ty::Const<'tcx>, B::TyConstId>,
pub(crate) mir_consts: IndexMap<mir::Const<'tcx>, B::MirConstId>,
pub(crate) layouts: IndexMap<rustc_abi::Layout<'tcx>, B::Layout>,
}
```
Since `rustc_smir` needs these stable types somewhere, using associated types is a good approach.
- **SmirContainer / SmirInterface**
```rust
/// A container which is used for TLS.
pub struct SmirContainer<'tcx, B: Bridge> {
pub tables: RefCell<Tables<'tcx, B>>,
pub cx: RefCell<SmirCtxt<'tcx, B>>,
}
impl<'tcx> SmirInterface for SmirContainer<'tcx, BridgeTys> {
// ...
}
/// Provides direct access to rustc's internal queries.
///
/// The [`crate::stable_mir::compiler_interface::SmirInterface`] must go through
/// this context to obtain rustc-level information.
pub struct SmirCtxt<'tcx, B: Bridge> {
tcx: TyCtxt<'tcx>,
_marker: PhantomData<B>,
}
```
This PR moves `Tables` from `SmirCtxt` to a new `SmirContainer` struct, since mutable borrows of `tables` should only be managed by `SmirInterface`. This change prevents `SmirCtxt` from holding separate borrows and requires passing `tables` explicitly when needed:
```rust
impl<'tcx, B: Bridge> SmirCtxt<'tcx, B> {
// ...
/// Get the body of an Instance which is already monomorphized.
pub fn instance_body(
&self,
instance: ty::Instance<'tcx>,
tables: &mut Tables<'tcx, B>,
) -> Option<Body<'tcx>> {
tables
.instance_has_body(instance)
.then(|| BodyBuilder::new(self.tcx, instance).build(tables))
}
// ...
}
```
This PR introduces `SmirContainer` as a separate struct rather than bundling it into a `SmirInterface` struct. This separation makes the architecture more modular and easier to reason about.
- **context/traits.rs**
We use this file to define traits that are used for encapsulating the associated functions in the rustc's internals. This is much easier to use and maintain than directly cramming everything into `SmirCtxt`. Here is a real-world use case:
```rust
impl RustcInternal for ExistentialTraitRef {
type T<'tcx> = rustc_ty::ExistentialTraitRef<'tcx>;
fn internal<'tcx>(
&self,
tables: &mut Tables<'_, BridgeTys>,
cx: &SmirCtxt<'tcx, BridgeTys>,
) -> Self::T<'tcx> {
use rustc_smir::context::SmirExistentialTraitRef;
cx.new_from_args(self.def_id.0.internal(tables, cx), self.generic_args.internal(tables, cx))
}
}
```
- **Separation of `rustc_smir::alloc`**
The previous `rustc_smir::alloc` had many direct calls to rustc queries. This PR splits it into two parts: `rustc_smir::alloc` and `stable_mir::alloc`. Following the same pattern as `SmirCtxt` and `SmirInterface`, the `rustc_smir::alloc` handles all direct interactions with rustc queries and performs the actual memory allocations, while the `stable_mir::alloc` is responsible for constructing stable components.
- **Removal of `convert/error.rs`**
We use `SmirError::from_internal` instead, since implementing `Stable` for these internal errors would be redundant—`tables` is not actually used. If we later need to add something like `LayoutError` to `stable_mir`, we could implement it as follows:
```rust
impl SmirError for stable_mir::LayoutError {
fn from_internal<T: Debug>(err: T) -> Self {
// ...
}
}
```
**Unresolved questions:**
- There are still a few direct calls to rustc's internals scattered across `impl Stable`s, but most of them appear to be relatively stable, e.g., `mir::interpret::ConstAllocation::inner(self)` and `mir::syntax::SwitchTargets::otherwise(self)`.
r? `@celinval`
