bjoernager/rust
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Foo<T> != Foo<U> under layout randomization

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previously field ordering was using the same seed for all instances of Foo,
now we pass seed values through the layout tree so that not only
the struct itself affects layout but also its fields
This commit is contained in:
The 8472 2024-11-16 01:55:07 +01:00
parent a580b5c379
commit a75617c223
5 changed files with 114 additions and 2 deletions
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10
compiler/rustc_ty_utils/src/layout.rs
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@ -347,6 +347,7 @@ fn layout_of_uncached<'tcx>(
size,
max_repr_align: None,
unadjusted_abi_align: element.align.abi,
randomization_seed: element.randomization_seed.wrapping_add(count),
})
}
ty::Slice(element) => {
@ -360,6 +361,8 @@ fn layout_of_uncached<'tcx>(
size: Size::ZERO,
max_repr_align: None,
unadjusted_abi_align: element.align.abi,
// adding a randomly chosen value to distinguish slices
randomization_seed: element.randomization_seed.wrapping_add(0x2dcba99c39784102),
})
}
ty::Str => tcx.mk_layout(LayoutData {
@ -371,6 +374,8 @@ fn layout_of_uncached<'tcx>(
size: Size::ZERO,
max_repr_align: None,
unadjusted_abi_align: dl.i8_align.abi,
// another random value
randomization_seed: 0xc1325f37d127be22,
}),
// Odd unit types.
@ -542,6 +547,7 @@ fn layout_of_uncached<'tcx>(
align,
max_repr_align: None,
unadjusted_abi_align: align.abi,
randomization_seed: e_ly.randomization_seed.wrapping_add(e_len),
})
}
@ -999,6 +1005,9 @@ fn coroutine_layout<'tcx>(
BackendRepr::Memory { sized: true }
};
// this is similar to how ReprOptions populates its field_shuffle_seed
let def_hash = tcx.def_path_hash(def_id).0.to_smaller_hash().as_u64();
let layout = tcx.mk_layout(LayoutData {
variants: Variants::Multiple {
tag,
@ -1019,6 +1028,7 @@ fn coroutine_layout<'tcx>(
align,
max_repr_align: None,
unadjusted_abi_align: align.abi,
randomization_seed: def_hash,
});
debug!("coroutine layout ({:?}): {:#?}", ty, layout);
Ok(layout)