Struct rustc_mir_dataflow::impls::EverInitializedPlaces

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pub struct EverInitializedPlaces<'a, 'mir, 'tcx> {
    body: &'mir Body<'tcx>,
    move_data: &'a MoveData<'tcx>,
}
Expand description

EverInitializedPlaces tracks all places that might have ever been initialized upon reaching a particular point in the control flow for a function, without an intervening StorageDead.

This dataflow is used to determine if an immutable local variable may be assigned to.

For example, in code like the following, we have corresponding dataflow information shown in the right-hand comments.

struct S;
fn foo(pred: bool) {                        // ever-init:
                                            // {          }
    let a = S; let mut b = S; let c; let d; // {a, b      }

    if pred {
        drop(a);                            // {a, b,     }
        b = S;                              // {a, b,     }

    } else {
        drop(b);                            // {a, b,      }
        d = S;                              // {a, b,    d }

    }                                       // {a, b,    d }

    c = S;                                  // {a, b, c, d }
}

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§body: &'mir Body<'tcx>§move_data: &'a MoveData<'tcx>

Implementations§

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impl<'a, 'mir, 'tcx> EverInitializedPlaces<'a, 'mir, 'tcx>

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pub fn new(body: &'mir Body<'tcx>, move_data: &'a MoveData<'tcx>) -> Self

Trait Implementations§

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impl<'tcx> AnalysisDomain<'tcx> for EverInitializedPlaces<'_, '_, 'tcx>

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type Domain = ChunkedBitSet<InitIndex>

There can be many more InitIndex than there are locals in a MIR body. We use a chunked bitset to avoid paying too high a memory footprint.

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const NAME: &'static str = "ever_init"

A descriptive name for this analysis. Used only for debugging. Read more
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fn bottom_value(&self, _: &Body<'tcx>) -> Self::Domain

Returns the initial value of the dataflow state upon entry to each basic block.
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fn initialize_start_block(&self, body: &Body<'tcx>, state: &mut Self::Domain)

Mutates the initial value of the dataflow state upon entry to the START_BLOCK. Read more
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type Direction = Forward

The direction of this analysis. Either Forward or Backward.
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impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, '_, 'tcx>

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type Idx = InitIndex

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fn domain_size(&self, _: &Body<'tcx>) -> usize

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fn statement_effect( &mut self, trans: &mut impl GenKill<Self::Idx>, stmt: &Statement<'tcx>, location: Location, )

See Analysis::apply_statement_effect. Note how the second arg differs.
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fn terminator_effect<'mir>( &mut self, trans: &mut Self::Domain, terminator: &'mir Terminator<'tcx>, location: Location, ) -> TerminatorEdges<'mir, 'tcx>

See Analysis::apply_terminator_effect.
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fn call_return_effect( &mut self, trans: &mut Self::Domain, block: BasicBlock, _return_places: CallReturnPlaces<'_, 'tcx>, )

See Analysis::apply_call_return_effect.
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fn before_statement_effect( &mut self, _trans: &mut impl GenKill<Self::Idx>, _statement: &Statement<'tcx>, _location: Location, )

See Analysis::apply_before_statement_effect. Note how the second arg differs.
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fn before_terminator_effect( &mut self, _trans: &mut Self::Domain, _terminator: &Terminator<'tcx>, _location: Location, )

See Analysis::apply_before_terminator_effect.
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fn switch_int_edge_effects<G: GenKill<Self::Idx>>( &mut self, _block: BasicBlock, _discr: &Operand<'tcx>, _edge_effects: &mut impl SwitchIntEdgeEffects<G>, )

See Analysis::apply_switch_int_edge_effects.
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impl<'a, 'tcx> HasMoveData<'tcx> for EverInitializedPlaces<'a, '_, 'tcx>

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fn move_data(&self) -> &MoveData<'tcx>

Auto Trait Implementations§

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impl<'a, 'mir, 'tcx> Freeze for EverInitializedPlaces<'a, 'mir, 'tcx>

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impl<'a, 'mir, 'tcx> !RefUnwindSafe for EverInitializedPlaces<'a, 'mir, 'tcx>

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impl<'a, 'mir, 'tcx> !Send for EverInitializedPlaces<'a, 'mir, 'tcx>

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impl<'a, 'mir, 'tcx> !Sync for EverInitializedPlaces<'a, 'mir, 'tcx>

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impl<'a, 'mir, 'tcx> Unpin for EverInitializedPlaces<'a, 'mir, 'tcx>

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impl<'a, 'mir, 'tcx> !UnwindSafe for EverInitializedPlaces<'a, 'mir, 'tcx>

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<T> Filterable for T

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fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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type Error = !

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type Output = T

Should always be Self
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

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fn upcast(self, interner: I) -> U

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impl<I, T> UpcastFrom<I, T> for T

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fn upcast_from(from: T, _tcx: I) -> T

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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<Tcx, T> Value<Tcx> for T
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default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T

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impl<T> ErasedDestructor for T
where T: 'static,

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Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes