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interpret: ImmTy: tighten sanity checks in offset logic

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This commit is contained in:
Ralf Jung 2024-08-24 14:11:28 +02:00
parent edbc000fa4
commit 493cf6a7e9
1 changed files with 15 additions and 6 deletions
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21
compiler/rustc_const_eval/src/interpret/operand.rs
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@ -319,6 +319,7 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
// some fieldless enum variants can have non-zero size but still `Aggregate` ABI... try
// to detect those here and also give them no data
_ if matches!(layout.abi, Abi::Aggregate { .. })
&& matches!(layout.variants, abi::Variants::Single { .. })
&& matches!(&layout.fields, abi::FieldsShape::Arbitrary { offsets, .. } if offsets.len() == 0) =>
{
Immediate::Uninit
@ -328,8 +329,9 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
assert_eq!(offset.bytes(), 0);
assert!(
match (self.layout.abi, layout.abi) {
(Abi::Scalar(..), Abi::Scalar(..)) => true,
(Abi::ScalarPair(..), Abi::ScalarPair(..)) => true,
(Abi::Scalar(l), Abi::Scalar(r)) => l.size(cx) == r.size(cx),
(Abi::ScalarPair(l1, l2), Abi::ScalarPair(r1, r2)) =>
l1.size(cx) == r1.size(cx) && l2.size(cx) == r2.size(cx),
_ => false,
},
"cannot project into {} immediate with equally-sized field {}\nouter ABI: {:#?}\nfield ABI: {:#?}",
@ -344,16 +346,23 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
(Immediate::ScalarPair(a_val, b_val), Abi::ScalarPair(a, b)) => {
assert_matches!(layout.abi, Abi::Scalar(..));
Immediate::from(if offset.bytes() == 0 {
debug_assert_eq!(layout.size, a.size(cx));
// It is "okay" to transmute from `usize` to a pointer (GVN relies on that).
// So only compare the size.
assert_eq!(layout.size, a.size(cx));
a_val
} else {
debug_assert_eq!(offset, a.size(cx).align_to(b.align(cx).abi));
debug_assert_eq!(layout.size, b.size(cx));
assert_eq!(offset, a.size(cx).align_to(b.align(cx).abi));
assert_eq!(layout.size, b.size(cx));
b_val
})
}
// everything else is a bug
_ => bug!("invalid field access on immediate {}, layout {:#?}", self, self.layout),
_ => bug!(
"invalid field access on immediate {} at offset {}, original layout {:#?}",
self,
offset.bytes(),
self.layout
),
};
ImmTy::from_immediate(inner_val, layout)