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Do not const pop unions

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as they can made to produce values whose types don't
match their underlying layout types which can lead to
ICEs on eval
This commit is contained in:
Gurinder Singh
2024-02-26 15:22:22 +05:30
parent 0250ef2571
commit 633c92cd6d
2 changed files with 47 additions and 14 deletions
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40
compiler/rustc_mir_transform/src/known_panics_lint.rs
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@@ -585,20 +585,32 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
val.into()
}
Aggregate(ref kind, ref fields) => Value::Aggregate {
fields: fields
.iter()
.map(|field| self.eval_operand(field).map_or(Value::Uninit, Value::Immediate))
.collect(),
variant: match **kind {
AggregateKind::Adt(_, variant, _, _, _) => variant,
AggregateKind::Array(_)
| AggregateKind::Tuple
| AggregateKind::Closure(_, _)
| AggregateKind::Coroutine(_, _)
| AggregateKind::CoroutineClosure(_, _) => VariantIdx::new(0),
},
},
Aggregate(ref kind, ref fields) => {
// Do not const pop union fields as they can be
// made to produce values that don't match their
// underlying layout's type (see ICE #121534).
// If the last element of the `Adt` tuple
// is `Some` it indicates the ADT is a union
if let AggregateKind::Adt(_, _, _, _, Some(_)) = **kind {
return None;
};
Value::Aggregate {
fields: fields
.iter()
.map(|field| {
self.eval_operand(field).map_or(Value::Uninit, Value::Immediate)
})
.collect(),
variant: match **kind {
AggregateKind::Adt(_, variant, _, _, _) => variant,
AggregateKind::Array(_)
| AggregateKind::Tuple
| AggregateKind::Closure(_, _)
| AggregateKind::Coroutine(_, _)
| AggregateKind::CoroutineClosure(_, _) => VariantIdx::new(0),
},
}
}
Repeat(ref op, n) => {
trace!(?op, ?n);