pub struct MaybeUninitializedPlaces<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
body: &'a Body<'tcx>,
move_data: &'a MoveData<'tcx>,
mark_inactive_variants_as_uninit: bool,
skip_unreachable_unwind: BitSet<BasicBlock>,
}
Expand description
MaybeUninitializedPlaces
tracks all places that might be
uninitialized 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-uninit:
// {a, b, c, d}
let a = S; let mut b = S; let c; let d; // { c, d}
if pred {
drop(a); // {a, c, d}
b = S; // {a, c, d}
} else {
drop(b); // { b, c, d}
d = S; // { b, c }
} // {a, b, c, d}
c = S; // {a, b, d}
}
To determine whether a place is definitely uninitialized at a
particular control-flow point, one can take the set-complement
of the data from MaybeInitializedPlaces
at the corresponding
control-flow point.
Similarly, at a given drop
statement, the set-intersection
between this data and MaybeInitializedPlaces
yields the set of
places that would require a dynamic drop-flag at that statement.
Fields§
§tcx: TyCtxt<'tcx>
§body: &'a Body<'tcx>
§move_data: &'a MoveData<'tcx>
§mark_inactive_variants_as_uninit: bool
§skip_unreachable_unwind: BitSet<BasicBlock>
Implementations§
Source§impl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx>
pub fn new( tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, move_data: &'a MoveData<'tcx>, ) -> Self
Sourcepub fn mark_inactive_variants_as_uninit(self) -> Self
pub fn mark_inactive_variants_as_uninit(self) -> Self
Causes inactive enum variants to be marked as “maybe uninitialized” after a switch on an enum discriminant.
This is correct in a vacuum but is not the default because it causes problems in the borrow
checker, where this information gets propagated along FakeEdge
s.
pub fn skipping_unreachable_unwind( self, unreachable_unwind: BitSet<BasicBlock>, ) -> Self
Source§impl<'tcx> MaybeUninitializedPlaces<'_, 'tcx>
impl<'tcx> MaybeUninitializedPlaces<'_, 'tcx>
fn update_bits( trans: &mut MixedBitSet<MovePathIndex>, path: MovePathIndex, state: DropFlagState, )
Trait Implementations§
Source§impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
impl<'tcx> Analysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
Source§type Domain = MixedBitSet<MovePathIndex>
type Domain = MixedBitSet<MovePathIndex>
There can be many more MovePathIndex
than there are locals in a MIR body.
We use a mixed bitset to avoid paying too high a memory footprint.
Source§const NAME: &'static str = "maybe_uninit"
const NAME: &'static str = "maybe_uninit"
Source§fn bottom_value(&self, _: &Body<'tcx>) -> Self::Domain
fn bottom_value(&self, _: &Body<'tcx>) -> Self::Domain
Source§fn initialize_start_block(&self, _: &Body<'tcx>, state: &mut Self::Domain)
fn initialize_start_block(&self, _: &Body<'tcx>, state: &mut Self::Domain)
START_BLOCK
. Read moreSource§fn apply_statement_effect(
&mut self,
trans: &mut Self::Domain,
_statement: &Statement<'tcx>,
location: Location,
)
fn apply_statement_effect( &mut self, trans: &mut Self::Domain, _statement: &Statement<'tcx>, location: Location, )
Source§fn apply_terminator_effect<'mir>(
&mut self,
trans: &mut Self::Domain,
terminator: &'mir Terminator<'tcx>,
location: Location,
) -> TerminatorEdges<'mir, 'tcx>
fn apply_terminator_effect<'mir>( &mut self, trans: &mut Self::Domain, terminator: &'mir Terminator<'tcx>, location: Location, ) -> TerminatorEdges<'mir, 'tcx>
Source§fn apply_call_return_effect(
&mut self,
trans: &mut Self::Domain,
_block: BasicBlock,
return_places: CallReturnPlaces<'_, 'tcx>,
)
fn apply_call_return_effect( &mut self, trans: &mut Self::Domain, _block: BasicBlock, return_places: CallReturnPlaces<'_, 'tcx>, )
Call
terminator. Read moreSource§fn apply_switch_int_edge_effects(
&mut self,
block: BasicBlock,
discr: &Operand<'tcx>,
edge_effects: &mut impl SwitchIntEdgeEffects<Self::Domain>,
)
fn apply_switch_int_edge_effects( &mut self, block: BasicBlock, discr: &Operand<'tcx>, edge_effects: &mut impl SwitchIntEdgeEffects<Self::Domain>, )
SwitchInt
terminator. Read moreSource§fn apply_before_statement_effect(
&mut self,
_state: &mut Self::Domain,
_statement: &Statement<'tcx>,
_location: Location,
)
fn apply_before_statement_effect( &mut self, _state: &mut Self::Domain, _statement: &Statement<'tcx>, _location: Location, )
Source§fn apply_before_terminator_effect(
&mut self,
_state: &mut Self::Domain,
_terminator: &Terminator<'tcx>,
_location: Location,
)
fn apply_before_terminator_effect( &mut self, _state: &mut Self::Domain, _terminator: &Terminator<'tcx>, _location: Location, )
Source§impl<'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
impl<'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
Auto Trait Implementations§
impl<'a, 'tcx> DynSend for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> DynSync for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> Freeze for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> !RefUnwindSafe for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> !Send for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> !Sync for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> Unpin for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> !UnwindSafe for MaybeUninitializedPlaces<'a, 'tcx>
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
Source§impl<T> Filterable for T
impl<T> Filterable for T
Source§fn filterable(
self,
filter_name: &'static str,
) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
Source§impl<T> Instrument for T
impl<T> Instrument for T
Source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
Source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
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 moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
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 moreSource§impl<P> IntoQueryParam<P> for P
impl<P> IntoQueryParam<P> for P
fn into_query_param(self) -> P
Source§impl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
Source§impl<T> Pointable for T
impl<T> Pointable for T
Source§impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
Source§impl<I, T> UpcastFrom<I, T> for T
impl<I, T> UpcastFrom<I, T> for T
fn upcast_from(from: T, _tcx: I) -> T
Source§impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T
Source§impl<T> WithSubscriber for T
impl<T> WithSubscriber for T
Source§fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
Source§fn with_current_subscriber(self) -> WithDispatch<Self>
fn with_current_subscriber(self) -> WithDispatch<Self>
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
impl<T> ErasedDestructor for Twhere
T: 'static,
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: 64 bytes