Struct EverInitializedPlaces 

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

EverInitializedPlaces tracks all initializations that may have occurred 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. Underscored indices are used to distinguish between multiple initializations of the same local variable, e.g. b_0 and b_1.

struct S;
#[rustfmt::skip]
fn foo(p: bool) {                           // ever-init:
                                            // {p,                  }
    let a = S; let mut b = S; let c; let d; // {p, a, b_0,          }

    if p {
        drop(a);                            // {p, a, b_0,          }
        b = S;                              // {p, a, b_0, b_1,     }

    } else {
        drop(b);                            // {p, a, b_0, b_1,     }
        d = S;                              // {p, a, b_0, b_1,    d}

    }                                       // {p, a, b_0, b_1,    d}

    c = S;                                  // {p, a, b_0, b_1, c, d}
}

Fields

body: &'a Body<'tcx>

move_data: &'a MoveData<'tcx>

Implementations

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

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

Trait Implementations

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

const NAME: &'static str = "ever_init"

A descriptive name for this analysis. Used only for debugging.

type Domain = MixedBitSet<InitIndex>

The type that holds the dataflow state at any given point in the program.

fn bottom_value(&self, _: &Body<'tcx>) -> Self::Domain

Returns the initial value of the dataflow state upon entry to each basic block.

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.

fn apply_primary_statement_effect( &self, state: &mut Self::Domain, stmt: &Statement<'tcx>, location: Location, )

Updates the current dataflow state with the effect of evaluating a statement.

fn apply_primary_terminator_effect<'mir>( &self, state: &mut Self::Domain, terminator: &'mir Terminator<'tcx>, location: Location, ) -> TerminatorEdges<'mir, 'tcx>

Updates the current dataflow state with the effect of evaluating a terminator.

fn apply_call_return_effect( &self, state: &mut Self::Domain, block: BasicBlock, _return_places: CallReturnPlaces<'_, 'tcx>, )

Updates the current dataflow state with the effect of a successful return from a Call terminator.

type Direction = Forward

The direction of this analysis. Either Forward or Backward.

type SwitchIntData = !

Auxiliary data used for analyzing SwitchInt terminators, if necessary.

fn apply_early_statement_effect( &self, _state: &mut Self::Domain, _statement: &Statement<'tcx>, _location: Location, )

Updates the current dataflow state with an “early” effect, i.e. one that occurs immediately before the given statement.

fn apply_early_terminator_effect( &self, _state: &mut Self::Domain, _terminator: &Terminator<'tcx>, _location: Location, )

Updates the current dataflow state with an effect that occurs immediately before the given terminator.

fn get_switch_int_data( &self, _block: BasicBlock, _discr: &Operand<'tcx>, ) -> Option<Self::SwitchIntData>

Used to update the current dataflow state with the effect of taking a particular branch in a SwitchInt terminator.

fn apply_switch_int_edge_effect( &self, _data: &mut Self::SwitchIntData, _state: &mut Self::Domain, _value: SwitchTargetValue, _targets: &SwitchTargets, )

See comments on get_switch_int_data.

fn iterate_to_fixpoint<'mir>( self, tcx: TyCtxt<'tcx>, body: &'mir Body<'tcx>, pass_name: Option<&'static str>, ) -> Results<'tcx, Self>

where Self: Sized, Self::Domain: DebugWithContext<Self>,

Finds the fixpoint for this dataflow problem.

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

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

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