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.
Revert <https://github.com/rust-lang/rust/pull/138084> to buy time to
consider options that avoids breaking downstream usages of cargo on
distributed `rustc-src` artifacts, where such cargo invocations fail due
to inability to inherit `lints` from workspace root manifest's
`workspace.lints` (this is only valid for the source rust-lang/rust
workspace, but not really the distributed `rustc-src` artifacts).
This breakage was reported in
<https://github.com/rust-lang/rust/issues/138304>.
This reverts commit 48caf81484, reversing
changes made to c6662879b2.
By naming them in `[workspace.lints.rust]` in the top-level
`Cargo.toml`, and then making all `compiler/` crates inherit them with
`[lints] workspace = true`. (I omitted `rustc_codegen_{cranelift,gcc}`,
because they're a bit different.)
The advantages of this over the current approach:
- It uses a standard Cargo feature, rather than special handling in
bootstrap. So, easier to understand, and less likely to get
accidentally broken in the future.
- It works for proc macro crates.
It's a shame it doesn't work for rustc-specific lints, as the comments
explain.
Remove `rustc_middle::mir::tcx` module.
This is a really weird module. For example, what does `tcx` in `rustc_middle::mir::tcx::PlaceTy` mean? The answer is "not much".
The top-level module comment says:
> Methods for the various MIR types. These are intended for use after
> building is complete.
Awfully broad for a module that has a handful of impl blocks for some MIR types, none of which really relates to `TyCtxt`. `git blame` indicates the comment is ancient, from 2015, and made sense then.
This module is now vestigial. This commit removes it and moves all the code within into `rustc_middle::mir::statement`. Some specifics:
- `Place`, `PlaceRef`, `Rvalue`, `Operand`, `BorrowKind`: they all have `impl` blocks in both the `tcx` and `statement` modules. The commit merges the former into the latter.
- `BinOp`, `UnOp`: they only have `impl` blocks in `tcx`. The commit moves these into `statement`.
- `PlaceTy`, `RvalueInitializationState`: they are defined in `tcx`. This commit moves them into `statement` *and* makes them available in `mir::*`, like many other MIR types.
r? `@tmandry`
This is a really weird module. For example, what does `tcx` in
`rustc_middle::mir::tcx::PlaceTy` mean? The answer is "not much".
The top-level module comment says:
> Methods for the various MIR types. These are intended for use after
> building is complete.
Awfully broad for a module that has a handful of impl blocks for some
MIR types, none of which really relates to `TyCtxt`. `git blame`
indicates the comment is ancient, from 2015, and made sense then.
This module is now vestigial. This commit removes it and moves all the
code within into `rustc_middle::mir::statement`. Some specifics:
- `Place`, `PlaceRef`, `Rvalue`, `Operand`, `BorrowKind`: they all have `impl`
blocks in both the `tcx` and `statement` modules. The commit merges
the former into the latter.
- `BinOp`, `UnOp`: they only have `impl` blocks in `tcx`. The commit
moves these into `statement`.
- `PlaceTy`, `RvalueInitializationState`: they are defined in `tcx`.
This commit moves them into `statement` *and* makes them available in
`mir::*`, like many other MIR types.
`rustc_mir_dataflow/src/elaborate_drops.rs` contains some infrastructure
used by a few MIR passes: the `elaborate_drop` function, the
`DropElaborator` trait, etc.
`rustc_mir_transform/src/elaborate_drops.rs` (same file name, different
crate) contains the `ElaborateDrops` pass. It relies on a lot of the
infrastructure from `rustc_mir_dataflow/src/elaborate_drops.rs`.
It turns out that the drop infrastructure is only used in
`rustc_mir_transform`, so this commit moves it there. (The only
exception is the small `DropFlagState` type, which is moved to the
existing `rustc_mir_dataflow/src/drop_flag_effects.rs`.) The file is
renamed from `rustc_mir_dataflow/src/elaborate_drops.rs` to
`rustc_mir_transform/src/elaborate_drop.rs` (with no trailing `s`)
because (a) the `elaborate_drop` function is the most important export,
and (b) `rustc_mir_transform/src/elaborate_drops.rs` already exists.
All the infrastructure pieces that used to be `pub` are now
`pub(crate)`, because they are now only used within
`rustc_mir_transform`.
Begin to implement type system layer of unsafe binders
Mostly TODOs, but there's a lot of match arms that are basically just noops so I wanted to split these out before I put up the MIR lowering/projection part of this logic.
r? oli-obk
Tracking:
- https://github.com/rust-lang/rust/issues/130516
Use `PtrMetadata` instead of `Len` in slice drop shims
I tried to do a bigger change in #134297 which didn't work, so here's the part I really wanted: Removing another use of `Len`, in favour of `PtrMetadata`.
Split into two commits where the first just adds a test, so you can look at the second commit to see how the drop shim for an array changes with this PR.
Reusing the same reviewer from the last one:
r? BoxyUwU
`rustc_span::symbol` defines some things that are re-exported from
`rustc_span`, such as `Symbol` and `sym`. But it doesn't re-export some
closely related things such as `Ident` and `kw`. So you can do `use
rustc_span::{Symbol, sym}` but you have to do `use
rustc_span::symbol::{Ident, kw}`, which is inconsistent for no good
reason.
This commit re-exports `Ident`, `kw`, and `MacroRulesNormalizedIdent`,
and changes many `rustc_span::symbol::` qualifiers in `compiler/` to
`rustc_span::`. This is a 200+ net line of code reduction, mostly
because many files with two `use rustc_span` items can be reduced to
one.
It is possible to avoid the clone as suggested in the comment. It would
require introducing an enum with two variants
`CloneBeforeModifying(&Domain)` and `Modifiable(&mut Domain)`. But it's
not worth the effort, because this code path just isn't very hot. E.g.
when compiling a large benchmark like `cargo-0.60.0` it's only hit a few
thousand times.
Switches to the idiom used elsewhere of calling `Analysis::bottom_value`
to initialize a `state` value outside a loop, and then using
`clone_from` to update it within the loop. This is simpler and has no
impact on performance.
Current `SwitchInt` handling has complicated control flow.
- The dataflow engine calls `Analysis::apply_switch_int_edge_effects`,
passing in an "applier" that impls `SwitchIntEdgeEffects`.
- `apply_switch_int_edge_effects` possibly calls `apply` on the applier,
passing it a closure.
- The `apply` method calls the closure on each `SwitchInt` edge.
- The closure operates on the edge.
I.e. control flow goes from the engine, to the analysis, to the applier
(which came from the engine), to the closure (which came from the
analysis). It took me a while to work this out.
This commit changes to a simpler structure that maintains the important
characteristics.
- The dataflow engine calls `Analysis::get_switch_int_data`.
- `get_switch_int_data` returns an `Option<Self::SwitchIntData>` value.
- If that returned value was `Some`, the dataflow engine calls
`Analysis::apply_switch_int_edge_effect` on each edge, passing the
`Self::SwitchIntData` value.
- `Analysis::apply_switch_int_edge_effect` operates on the edge.
I.e. control flow goes from the engine, to the analysis, to the
engine, to the analysis.
Added:
- The `Analysis::SwitchIntData` assoc type and the
`Analysis::get_switch_int_data` method. Both only need to be
defined by analyses that look at `SwitchInt` terminators.
- The `MaybePlacesSwitchIntData` struct, which has three fields.
Changes:
- `Analysis::apply_switch_int_edge_effects` becomes
`Analysis::apply_switch_int_edge_effect`, which is a little simpler
because it's dealing with a single edge instead of all edges.
Removed:
- The `SwitchIntEdgeEffects` trait, and its two impls:
`BackwardSwitchIntEdgeEffectsApplier` (which has six fields) and
`ForwardSwitchIntEdgeEffectsApplier` structs (which has four fields).
- The closure.
The new structure is more concise and simpler.
`rustc_mir_dataflow` has a typedef `AbstractElem` that is equal to
`ProjectionElem<AbstractOperand, AbstractType>`. `AbstractOperand` and
`AbstractType` are both unit types. There is also has a trait `Lift` to
convert a `PlaceElem` to an `AbstractElem`.
But `rustc_mir_middle` already has a typedef `ProjectionKind` that is
equal to `ProjectionElem<(), ()>`, which is equivalent to
`AbstractElem`. So this commit reuses `ProjectionKind` in
`rustc_mir_dataflow`, removes `AbstractElem`, and simplifies the `Lift`
trait.
In most places, the `early` method is listed before the corresponding
`primary` method, like you'd expect. This commit fixes two places where
that isn't the case.
The words "before" and "after" have an obvious temporal meaning, e.g.
`seek_before_primary_effect`,
`visit_statement_{before,after}_primary_effect`. But "before" is also
used to name the effect that occurs before the primary effect of a
statement/terminator; this is `Effect::Before`. This leads to the
confusing possibility of talking about things happening "before/after
the before event".
This commit removes this awkward overloading of "before" by renaming
`Effect::Before` as `Effect::Early`. It also renames some of the
`Analysis` and `ResultsVisitor` methods to be more consistent.
Here are the before and after names:
- `Effect::{Before,Primary}` -> `Effect::{Early,Primary}`
- `apply_before_statement_effect` -> `apply_early_statement_effect`
- `apply_statement_effect` -> `apply_primary_statement_effect`
- `visit_statement_before_primary_effect` -> `visit_after_early_statement_effect`
- `visit_statement_after_primary_effect` -> `visit_after_primary_statement_effect`
(And s/statement/terminator/ for all the terminator events.)
Currently they are called (most common) `state`, or `trans`, or (rare)
`on_entry`. I think `trans` is short for "transfer function", which
perhaps made more sense when `GenKillAnalysis` existed. Using `state`
everywhere now is more consistent.
They are only present because it's currently defined in terms of the
domains of `Borrows` and `MaybeUninitializedPlaces` and
`EverInitializedPlaces` via associated types. This commit introduces
typedefs for those domains, avoiding the lifetimes.
