pub struct MaybeInitializedPlaces<'a, 'mir, 'tcx> {
    tcx: TyCtxt<'tcx>,
    body: &'mir Body<'tcx>,
    move_data: &'a MoveData<'tcx>,
    skip_unreachable_unwind: bool,
}
Expand description

MaybeInitializedPlaces tracks all places that might be initialized upon reaching a particular point in the control flow for a function.

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

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

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

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

    }                                       // {a, b,    d}

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

To determine whether a place must be initialized at a particular control-flow point, one can take the set-difference between this data and the data from MaybeUninitializedPlaces at the corresponding control-flow point.

Similarly, at a given drop statement, the set-intersection between this data and MaybeUninitializedPlaces yields the set of places that would require a dynamic drop-flag at that statement.

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

Implementations§

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

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

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pub fn skipping_unreachable_unwind(self) -> Self

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pub fn is_unwind_dead( &self, place: Place<'tcx>, state: &MaybeReachable<ChunkedBitSet<MovePathIndex>>, ) -> bool

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

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fn update_bits( trans: &mut impl GenKill<MovePathIndex>, path: MovePathIndex, state: DropFlagState, )

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

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type Domain = MaybeReachable<ChunkedBitSet<MovePathIndex>>

There can be many more MovePathIndex 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 = "maybe_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<'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 MaybeInitializedPlaces<'_, '_, 'tcx>

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type Idx = MovePathIndex

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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>, statement: &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, state: &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 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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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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impl<'a, 'mir, 'tcx> HasMoveData<'tcx> for MaybeInitializedPlaces<'a, 'mir, 'tcx>

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

Auto Trait Implementations§

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

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

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

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

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

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

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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>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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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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impl<P> IntoQueryParam<P> for P

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

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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
where Tcx: DepContext,

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

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<'a, T> Captures<'a> for T
where T: ?Sized,

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

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impl<T> MaybeSendSync for T

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: 32 bytes