bjoernager/rust
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clean up struct layout code

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This commit is contained in:
Lukas Markeffsky 2023-07-02 14:06:56 +02:00
parent 4b6749b21e
commit 478071ba9d
2 changed files with 41 additions and 36 deletions
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69
compiler/rustc_ty_utils/src/layout.rs
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@ -463,38 +463,43 @@ fn layout_of_uncached<'tcx>(
));
}
tcx.mk_layout(
cx.layout_of_struct_or_enum(
&def.repr(),
&variants,
def.is_enum(),
def.is_unsafe_cell(),
tcx.layout_scalar_valid_range(def.did()),
|min, max| Integer::repr_discr(tcx, ty, &def.repr(), min, max),
def.is_enum()
.then(|| def.discriminants(tcx).map(|(v, d)| (v, d.val as i128)))
.into_iter()
.flatten(),
def.repr().inhibit_enum_layout_opt()
|| def
.variants()
.iter_enumerated()
.any(|(i, v)| v.discr != ty::VariantDiscr::Relative(i.as_u32())),
{
let param_env = tcx.param_env(def.did());
def.is_struct()
&& match def.variants().iter().next().and_then(|x| x.fields.raw.last())
{
Some(last_field) => tcx
.type_of(last_field.did)
.subst_identity()
.is_sized(tcx, param_env),
None => false,
}
},
)
.ok_or_else(|| error(cx, LayoutError::SizeOverflow(ty)))?,
)
let get_discriminant_type =
|min, max| Integer::repr_discr(tcx, ty, &def.repr(), min, max);
let discriminants_iter = || {
def.is_enum()
.then(|| def.discriminants(tcx).map(|(v, d)| (v, d.val as i128)))
.into_iter()
.flatten()
};
let dont_niche_optimize_enum = def.repr().inhibit_enum_layout_opt()
|| def
.variants()
.iter_enumerated()
.any(|(i, v)| v.discr != ty::VariantDiscr::Relative(i.as_u32()));
let maybe_unsized = def.is_struct()
&& def.non_enum_variant().fields.raw.last().is_some_and(|last_field| {
let param_env = tcx.param_env(def.did());
!tcx.type_of(last_field.did).subst_identity().is_sized(tcx, param_env)
});
let Some(layout) = cx.layout_of_struct_or_enum(
&def.repr(),
&variants,
def.is_enum(),
def.is_unsafe_cell(),
tcx.layout_scalar_valid_range(def.did()),
get_discriminant_type,
discriminants_iter(),
dont_niche_optimize_enum,
!maybe_unsized,
) else {
return Err(error(cx, LayoutError::SizeOverflow(ty)));
};
tcx.mk_layout(layout)
}
// Types with no meaningful known layout.