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Auto merge of #103917 - oli-obk:layout_math, r=RalfJung,lcnr

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Various cleanups around scalar layout restrictions

Pulled out of https://github.com/rust-lang/rust/pull/103724
This commit is contained in:
bors 2022-11-27 10:35:00 +00:00
commit df04d28163
16 changed files with 261 additions and 129 deletions
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16
compiler/rustc_const_eval/src/interpret/validity.rs
View file

@ -785,18 +785,10 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
}
}
Abi::ScalarPair(a_layout, b_layout) => {
// There is no `rustc_layout_scalar_valid_range_start` for pairs, so
// we would validate these things as we descend into the fields,
// but that can miss bugs in layout computation. Layout computation
// is subtle due to enums having ScalarPair layout, where one field
// is the discriminant.
if cfg!(debug_assertions)
&& !a_layout.is_uninit_valid()
&& !b_layout.is_uninit_valid()
{
// We can only proceed if *both* scalars need to be initialized.
// FIXME: find a way to also check ScalarPair when one side can be uninit but
// the other must be init.
// We can only proceed if *both* scalars need to be initialized.
// FIXME: find a way to also check ScalarPair when one side can be uninit but
// the other must be init.
if !a_layout.is_uninit_valid() && !b_layout.is_uninit_valid() {
let (a, b) =
self.read_immediate(op, "initiailized scalar value")?.to_scalar_pair();
self.visit_scalar(a, a_layout)?;

11
compiler/rustc_const_eval/src/transform/validate.rs
View file

@ -81,6 +81,7 @@ struct TypeChecker<'a, 'tcx> {
}
impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
#[track_caller]
fn fail(&self, location: Location, msg: impl AsRef<str>) {
let span = self.body.source_info(location).span;
// We use `delay_span_bug` as we might see broken MIR when other errors have already
@ -226,12 +227,12 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
let check_equal = |this: &Self, location, f_ty| {
if !this.mir_assign_valid_types(ty, f_ty) {
this.fail(
location,
format!(
"Field projection `{:?}.{:?}` specified type `{:?}`, but actual type is `{:?}`",
parent, f, ty, f_ty
location,
format!(
"Field projection `{:?}.{:?}` specified type `{:?}`, but actual type is `{:?}`",
parent, f, ty, f_ty
)
)
)
}
};