Enum rustc_mir_dataflow::value_analysis::State

pub enum State<V> {
    Unreachable,
    Reachable(StateData<V>),
}

The dataflow state for an instance of ValueAnalysis.

Every instance specifies a lattice that represents the possible values of a single tracked place. If we call this lattice V and set of tracked places P, then a State is an element of {unreachable} ∪ (P -> V). This again forms a lattice, where the bottom element is unreachable and the top element is the mapping p ↦ ⊤. Note that the mapping p ↦ ⊥ is not the bottom element (because joining an unreachable and any other reachable state yields a reachable state). All operations on unreachable states are ignored.

Flooding means assigning a value (by default ⊤) to all tracked projections of a given place.

Variants

Unreachable

Reachable(StateData<V>)

Implementations

impl<V: Clone + HasBottom> State<V>

pub fn new_reachable() -> State<V>

pub fn all_bottom(&self) -> bool

fn is_reachable(&self) -> bool

pub fn flood_with(&mut self, place: PlaceRef<'_>, map: &Map<'_>, value: V)

Assign value to all places that are contained in place or may alias one.

pub fn flood(&mut self, place: PlaceRef<'_>, map: &Map<'_>)

where V: HasTop,

Assign TOP to all places that are contained in place or may alias one.

fn flood_discr_with(&mut self, place: PlaceRef<'_>, map: &Map<'_>, value: V)

Assign value to the discriminant of place and all places that may alias it.

pub fn flood_discr(&mut self, place: PlaceRef<'_>, map: &Map<'_>)

where V: HasTop,

Assign TOP to the discriminant of place and all places that may alias it.

pub fn flood_with_tail_elem( &mut self, place: PlaceRef<'_>, tail_elem: Option<TrackElem>, map: &Map<'_>, value: V, )

This method is the most general version of the flood_* method.

Assign value on the given place and all places that may alias it. In particular, when the given place has a variant downcast, we invoke the function on all the other variants.

tail_elem allows to support discriminants that are not a place in MIR, but that we track as such.

fn insert_idx( &mut self, target: PlaceIndex, result: ValueOrPlace<V>, map: &Map<'_>, )

Low-level method that assigns to a place. This does nothing if the place is not tracked.

The target place must have been flooded before calling this method.

pub fn insert_value_idx(&mut self, target: PlaceIndex, value: V, map: &Map<'_>)

Low-level method that assigns a value to a place. This does nothing if the place is not tracked.

The target place must have been flooded before calling this method.

pub fn insert_place_idx( &mut self, target: PlaceIndex, source: PlaceIndex, map: &Map<'_>, )

Copies source to target, including all tracked places beneath.

If target contains a place that is not contained in source, it will be overwritten with Top. Also, because this will copy all entries one after another, it may only be used for places that are non-overlapping or identical.

The target place must have been flooded before calling this method.

pub fn assign( &mut self, target: PlaceRef<'_>, result: ValueOrPlace<V>, map: &Map<'_>, )

where V: HasTop,

Helper method to interpret target = result.

pub fn assign_discr( &mut self, target: PlaceRef<'_>, result: ValueOrPlace<V>, map: &Map<'_>, )

where V: HasTop,

Helper method for assignments to a discriminant.

pub fn try_get(&self, place: PlaceRef<'_>, map: &Map<'_>) -> Option<V>

Retrieve the value stored for a place, or None if it is not tracked.

pub fn try_get_discr(&self, place: PlaceRef<'_>, map: &Map<'_>) -> Option<V>

Retrieve the discriminant stored for a place, or None if it is not tracked.

pub fn try_get_len(&self, place: PlaceRef<'_>, map: &Map<'_>) -> Option<V>

Retrieve the slice length stored for a place, or None if it is not tracked.

pub fn try_get_idx(&self, place: PlaceIndex, map: &Map<'_>) -> Option<V>

Retrieve the value stored for a place index, or None if it is not tracked.

pub fn get(&self, place: PlaceRef<'_>, map: &Map<'_>) -> V

where V: HasBottom + HasTop,

Retrieve the value stored for a place, or ⊤ if it is not tracked.

This method returns ⊥ if the place is tracked and the state is unreachable.

pub fn get_discr(&self, place: PlaceRef<'_>, map: &Map<'_>) -> V

where V: HasBottom + HasTop,

Retrieve the value stored for a place, or ⊤ if it is not tracked.

This method returns ⊥ the current state is unreachable.

pub fn get_len(&self, place: PlaceRef<'_>, map: &Map<'_>) -> V

where V: HasBottom + HasTop,

Retrieve the value stored for a place, or ⊤ if it is not tracked.

This method returns ⊥ the current state is unreachable.

pub fn get_idx(&self, place: PlaceIndex, map: &Map<'_>) -> V

where V: HasBottom + HasTop,

Retrieve the value stored for a place index, or ⊤ if it is not tracked.

This method returns ⊥ the current state is unreachable.

Trait Implementations

impl<V: Clone> Clone for State<V>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<V: Debug> Debug for State<V>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'tcx, T> DebugWithContext<ValueAnalysisWrapper<T>> for State<T::Value>

where T: ValueAnalysis<'tcx>, T::Value: Debug,

This is used to visualize the dataflow analysis.

fn fmt_with( &self, ctxt: &ValueAnalysisWrapper<T>, f: &mut Formatter<'_>, ) -> Result

fn fmt_diff_with( &self, old: &Self, ctxt: &ValueAnalysisWrapper<T>, f: &mut Formatter<'_>, ) -> Result

Print the difference between self and old.

impl<V: JoinSemiLattice + Clone + HasBottom> JoinSemiLattice for State<V>

fn join(&mut self, other: &Self) -> bool

Computes the least upper bound of two elements, storing the result in self and returning true if self has changed.

impl<V: PartialEq> PartialEq for State<V>

fn eq(&self, other: &State<V>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<V: Eq> Eq for State<V>

impl<V> StructuralPartialEq for State<V>

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.