pub type Layout = LayoutData<RustcFieldIdx, RustcEnumVariantIdx>;
Aliased Type§
struct Layout {
pub fields: FieldsShape<RustcFieldIdx>,
pub variants: Variants<RustcFieldIdx, RustcEnumVariantIdx>,
pub backend_repr: BackendRepr,
pub largest_niche: Option<Niche>,
pub align: AbiAndPrefAlign,
pub size: Size,
pub max_repr_align: Option<Align>,
pub unadjusted_abi_align: Align,
}
Fields§
§fields: FieldsShape<RustcFieldIdx>
Says where the fields are located within the layout.
variants: Variants<RustcFieldIdx, RustcEnumVariantIdx>
Encodes information about multi-variant layouts.
Even with Multiple
variants, a layout still has its own fields! Those are then
shared between all variants. One of them will be the discriminant,
but e.g. coroutines can have more.
To access all fields of this layout, both fields
and the fields of the active variant
must be taken into account.
backend_repr: BackendRepr
The backend_repr
defines how this data will be represented to the codegen backend,
and encodes value restrictions via valid_range
.
Note that this is entirely orthogonal to the recursive structure defined by
variants
and fields
; for example, ManuallyDrop<Result<isize, isize>>
has
IrForm::ScalarPair
! So, even with non-Memory
backend_repr
, fields
and variants
have to be taken into account to find all fields of this layout.
largest_niche: Option<Niche>
The leaf scalar with the largest number of invalid values
(i.e. outside of its valid_range
), if it exists.
align: AbiAndPrefAlign
§size: Size
§max_repr_align: Option<Align>
The largest alignment explicitly requested with repr(align)
on this type or any field.
Only used on i686-windows, where the argument passing ABI is different when alignment is
requested, even if the requested alignment is equal to the natural alignment.
unadjusted_abi_align: Align
The alignment the type would have, ignoring any repr(align)
but including repr(packed)
.
Only used on aarch64-linux, where the argument passing ABI ignores the requested alignment
in some cases.