Struct rustc_mir_dataflow::impls::MaybeUninitializedPlaces
source · [−]pub struct MaybeUninitializedPlaces<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
body: &'a Body<'tcx>,
mdpe: &'a MoveDataParamEnv<'tcx>,
mark_inactive_variants_as_uninit: bool,
}
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 must be uninitialized at a
particular control-flow point, one can take the set-difference
between this data and 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>
mdpe: &'a MoveDataParamEnv<'tcx>
mark_inactive_variants_as_uninit: bool
Implementations
sourceimpl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx>
pub fn new(
tcx: TyCtxt<'tcx>,
body: &'a Body<'tcx>,
mdpe: &'a MoveDataParamEnv<'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.
sourceimpl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> MaybeUninitializedPlaces<'a, 'tcx>
fn update_bits(
trans: &mut impl GenKill<MovePathIndex>,
path: MovePathIndex,
state: DropFlagState
)
Trait Implementations
sourceimpl<'tcx> AnalysisDomain<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
impl<'tcx> AnalysisDomain<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
type Domain = ChunkedBitSet<MovePathIndex>
type Domain = ChunkedBitSet<MovePathIndex>
sourceconst NAME: &'static str = "maybe_uninit"
const NAME: &'static str = "maybe_uninit"
sourcefn bottom_value(&self, _: &Body<'tcx>) -> Self::Domain
fn bottom_value(&self, _: &Body<'tcx>) -> Self::Domain
sourcefn initialize_start_block(&self, _: &Body<'tcx>, state: &mut Self::Domain)
fn initialize_start_block(&self, _: &Body<'tcx>, state: &mut Self::Domain)
START_BLOCK
. Read moresourceimpl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx>
type Idx = MovePathIndex
sourcefn statement_effect(
&self,
trans: &mut impl GenKill<Self::Idx>,
_statement: &Statement<'tcx>,
location: Location
)
fn statement_effect(
&self,
trans: &mut impl GenKill<Self::Idx>,
_statement: &Statement<'tcx>,
location: Location
)
Analysis::apply_statement_effect
.sourcefn terminator_effect(
&self,
trans: &mut impl GenKill<Self::Idx>,
_terminator: &Terminator<'tcx>,
location: Location
)
fn terminator_effect(
&self,
trans: &mut impl GenKill<Self::Idx>,
_terminator: &Terminator<'tcx>,
location: Location
)
Analysis::apply_terminator_effect
.sourcefn call_return_effect(
&self,
trans: &mut impl GenKill<Self::Idx>,
_block: BasicBlock,
return_places: CallReturnPlaces<'_, 'tcx>
)
fn call_return_effect(
&self,
trans: &mut impl GenKill<Self::Idx>,
_block: BasicBlock,
return_places: CallReturnPlaces<'_, 'tcx>
)
Analysis::apply_call_return_effect
.sourcefn switch_int_edge_effects<G: GenKill<Self::Idx>>(
&self,
block: BasicBlock,
discr: &Operand<'tcx>,
edge_effects: &mut impl SwitchIntEdgeEffects<G>
)
fn switch_int_edge_effects<G: GenKill<Self::Idx>>(
&self,
block: BasicBlock,
discr: &Operand<'tcx>,
edge_effects: &mut impl SwitchIntEdgeEffects<G>
)
Analysis::apply_switch_int_edge_effects
.sourcefn before_statement_effect(
&self,
_trans: &mut impl GenKill<Self::Idx>,
_statement: &Statement<'tcx>,
_location: Location
)
fn before_statement_effect(
&self,
_trans: &mut impl GenKill<Self::Idx>,
_statement: &Statement<'tcx>,
_location: Location
)
Analysis::apply_before_statement_effect
.sourcefn before_terminator_effect(
&self,
_trans: &mut impl GenKill<Self::Idx>,
_terminator: &Terminator<'tcx>,
_location: Location
)
fn before_terminator_effect(
&self,
_trans: &mut impl GenKill<Self::Idx>,
_terminator: &Terminator<'tcx>,
_location: Location
)
Analysis::apply_before_terminator_effect
.sourcefn yield_resume_effect(
&self,
_trans: &mut impl GenKill<Self::Idx>,
_resume_block: BasicBlock,
_resume_place: Place<'tcx>
)
fn yield_resume_effect(
&self,
_trans: &mut impl GenKill<Self::Idx>,
_resume_block: BasicBlock,
_resume_place: Place<'tcx>
)
Analysis::apply_yield_resume_effect
.sourceimpl<'a, 'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'a, 'tcx>
impl<'a, 'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'a, 'tcx>
Auto Trait Implementations
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>where
'tcx: 'a,
impl<'a, 'tcx> !UnwindSafe for MaybeUninitializedPlaces<'a, 'tcx>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
sourceimpl<'tcx, A, D> RustcPeekAt<'tcx> for Awhere
A: Analysis<'tcx, Domain = D> + HasMoveData<'tcx>,
D: JoinSemiLattice + Clone + BitSetExt<MovePathIndex>,
impl<'tcx, A, D> RustcPeekAt<'tcx> for Awhere
A: Analysis<'tcx, Domain = D> + HasMoveData<'tcx>,
D: JoinSemiLattice + Clone + BitSetExt<MovePathIndex>,
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