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Remove Unknown state in favor of Value(Top)

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This commit is contained in:
Jannis Christopher Köhl 2022-10-05 22:01:33 +02:00
parent 1765587846
commit 7ab1ba95de
2 changed files with 21 additions and 20 deletions
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31
compiler/rustc_mir_dataflow/src/value_analysis.rs
View File

@ -183,15 +183,15 @@ pub trait ValueAnalysis<'tcx> {
.map()
.find(place.as_ref())
.map(ValueOrPlaceOrRef::Ref)
.unwrap_or(ValueOrPlaceOrRef::Unknown),
.unwrap_or(ValueOrPlaceOrRef::top()),
Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
state.flood(place.as_ref(), self.map());
ValueOrPlaceOrRef::Unknown
ValueOrPlaceOrRef::top()
}
Rvalue::CopyForDeref(place) => {
self.handle_operand(&Operand::Copy(*place), state).into()
}
_ => ValueOrPlaceOrRef::Unknown,
_ => ValueOrPlaceOrRef::top(),
}
}
@ -218,7 +218,7 @@ pub trait ValueAnalysis<'tcx> {
self.map()
.find(place.as_ref())
.map(ValueOrPlace::Place)
.unwrap_or(ValueOrPlace::Unknown)
.unwrap_or(ValueOrPlace::top())
}
}
}
@ -511,9 +511,6 @@ impl<V: Clone + HasTop> State<V> {
self.assign_place_idx(target_deref, source, map);
}
}
ValueOrPlaceOrRef::Unknown => {
self.flood_idx(target, map);
}
}
}
@ -756,27 +753,35 @@ impl<'a> Iterator for Children<'a> {
}
}
}
// FIXME: See if we can get rid of `Unknown`.
pub enum ValueOrPlace<V> {
Value(V),
Place(PlaceIndex),
Unknown,
}
impl<V: HasTop> ValueOrPlace<V> {
pub fn top() -> Self {
ValueOrPlace::Value(V::top())
}
}
pub enum ValueOrPlaceOrRef<V> {
Value(V),
Place(PlaceIndex),
Ref(PlaceIndex),
Unknown,
Ref(PlaceIndex)
}
impl<V: HasTop> ValueOrPlaceOrRef<V> {
pub fn top() -> Self {
ValueOrPlaceOrRef::Value(V::top())
}
}
impl<V> From<ValueOrPlace<V>> for ValueOrPlaceOrRef<V> {
fn from(x: ValueOrPlace<V>) -> Self {
match x {
ValueOrPlace::Value(value) => ValueOrPlaceOrRef::Value(value),
ValueOrPlace::Place(place) => ValueOrPlaceOrRef::Place(place),
ValueOrPlace::Unknown => ValueOrPlaceOrRef::Unknown,
}
}
}

10
compiler/rustc_mir_transform/src/dataflow_const_prop.rs
View File

@ -105,8 +105,8 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'tcx> {
.ecx
.misc_cast(&operand, *ty)
.map(|result| ValueOrPlaceOrRef::Value(self.wrap_immediate(result, *ty)))
.unwrap_or(ValueOrPlaceOrRef::Unknown),
_ => ValueOrPlaceOrRef::Unknown,
.unwrap_or(ValueOrPlaceOrRef::top()),
_ => ValueOrPlaceOrRef::top(),
}
}
Rvalue::BinaryOp(op, box (left, right)) => {
@ -156,7 +156,6 @@ impl<'tcx> ValueAnalysis<'tcx> for ConstAnalysis<'tcx> {
let value = match self.handle_operand(discr, state) {
ValueOrPlace::Value(value) => value,
ValueOrPlace::Place(place) => state.get_idx(place, self.map()),
ValueOrPlace::Unknown => FlatSet::Top,
};
let result = match value {
FlatSet::Top => FlatSet::Top,
@ -241,7 +240,6 @@ impl<'tcx> ConstAnalysis<'tcx> {
let value = match self.handle_operand(op, state) {
ValueOrPlace::Value(value) => value,
ValueOrPlace::Place(place) => state.get_idx(place, &self.map),
ValueOrPlace::Unknown => FlatSet::Top,
};
match value {
FlatSet::Top => FlatSet::Top,
@ -384,9 +382,7 @@ impl<'tcx, 'map, 'a> Visitor<'tcx> for OperandCollector<'tcx, 'map, 'a> {
FlatSet::Elem(value) => {
self.visitor.before_effect.insert((location, *place), value);
}
FlatSet::Bottom => {
// This only happens if this location is unreachable.
}
FlatSet::Bottom => (),
}
}
_ => (),