pub struct MaybeInitializedPlaces<'a, 'tcx> {
    tcx: TyCtxt<'tcx>,
    body: &'a Body<'tcx>,
    mdpe: &'a MoveDataParamEnv<'tcx>,
}
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.

Fields§

§tcx: TyCtxt<'tcx>§body: &'a Body<'tcx>§mdpe: &'a MoveDataParamEnv<'tcx>

Implementations§

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

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pub fn new(
    tcx: TyCtxt<'tcx>,
    body: &'a Body<'tcx>,
    mdpe: &'a MoveDataParamEnv<'tcx>
) -> Self

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

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

Trait Implementations§

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

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type Domain = ChunkedBitSet<MovePathIndex>

The type that holds the dataflow state at any given point in the program.
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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 statement_effect(
    &self,
    trans: &mut impl GenKill<Self::Idx>,
    statement: &Statement<'tcx>,
    location: Location
)

See Analysis::apply_statement_effect.
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fn terminator_effect(
    &self,
    trans: &mut impl GenKill<Self::Idx>,
    terminator: &Terminator<'tcx>,
    location: Location
)

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

See Analysis::apply_before_statement_effect.
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fn before_terminator_effect(
    &self,
    _trans: &mut impl GenKill<Self::Idx>,
    _terminator: &Terminator<'tcx>,
    _location: Location
)

See Analysis::apply_before_terminator_effect.
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fn yield_resume_effect(
    &self,
    _trans: &mut impl GenKill<Self::Idx>,
    _resume_block: BasicBlock,
    _resume_place: Place<'tcx>
)

See Analysis::apply_yield_resume_effect.
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impl<'a, 'tcx> HasMoveData<'tcx> for MaybeInitializedPlaces<'a, 'tcx>

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

Auto Trait Implementations§

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

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

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

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impl<'a, 'tcx> Unpin for MaybeInitializedPlaces<'a, 'tcx>where
    'tcx: 'a,

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

Blanket Implementations§

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impl<T> Any for Twhere
    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 Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

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

const: unstable · source§

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

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

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<'tcx, A, D> RustcPeekAt<'tcx> for Awhere
    A: Analysis<'tcx, Domain = D> + HasMoveData<'tcx>,
    D: JoinSemiLattice + Clone + BitSetExt<MovePathIndex>,

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fn peek_at(
    &self,
    tcx: TyCtxt<'tcx>,
    place: Place<'tcx>,
    flow_state: &<A as AnalysisDomain<'tcx>>::Domain,
    call: PeekCall
)

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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

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 Twhere
    U: TryFrom<T>,

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

The type returned in the event of a conversion error.
const: unstable · source§

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

Performs the conversion.

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: 24 bytes