Struct Layout 

pub struct Layout {
    pub size: Size,
    pub align: Size,
    pub discriminator: Option<Discriminator>,
    pub inhabited: InhabitedPredicate,
    pub variant_layouts: IndexVec<VariantId, Option<VariantLayout>>,
    pub repr: ReprOptions,
}

Type layout information.

Does not include information about niches. If the type does not have a fully known layout (e.g. it is ?Sized) some of the layout parts are not available.

Fields

size: Size

The size of the type in bytes.

align: Size

The alignment, in bytes.

discriminator: Option<Discriminator>

Decision tree that determines the active variant by reading memory. Only Some for enums.

inhabited: InhabitedPredicate

Whether the type has any valid value. Note that uninhabited types can have arbitrary layouts: (u32, !) has space for the u32 and enum E2 { A, B(!), C(i32, !) } may have space for a discriminant.

variant_layouts: IndexVec<VariantId, Option<VariantLayout>>

Map from VariantId to the corresponding field layouts. Some variants don’t have a meaningful layout due to being uninhabited (though an uninhabited variant may have a layout). Structs and unions are modeled as having exactly one variant.

repr: ReprOptions

The representation options of this type declaration as annotated by the user.

Implementations

impl Layout

pub fn for_type( krate: &TranslatedCrate, kind: &TypeDeclKind, repr: ReprOptions, ) -> Option<Self>

Construct a layout for this type. The returned layout contains no size-related information.

pub fn is_variant_always_uninhabited(&self, variant_id: VariantId) -> bool

pub fn is_variant_always_inhabited(&self, variant_id: VariantId) -> bool

pub fn is_c_repr(&self) -> bool

Trait Implementations

impl AstVisitable for Layout

fn drive<V: VisitAst>(&self, v: &mut V) -> ControlFlow<V::Break>

Recursively visit this type with the provided visitor. This calls the visitor’s visit_$any method if it exists, otherwise visit_inner.

fn drive_mut<V: VisitAstMut>(&mut self, v: &mut V) -> ControlFlow<V::Break>

Recursively visit this type with the provided visitor. This calls the visitor’s visit_$any method if it exists, otherwise visit_inner.

fn drive_two<V: ZipAst>(&self, other: &Self, v: &mut V) -> ControlFlow<V::Break>

Recursively visit this type with the provided visitor. This calls the visitor’s visit_$any method if it exists, otherwise visit_inner.

fn name(&self) -> &'static str

The name of the type, used for debug logging.

fn dyn_visit<T: AstVisitable>(&self, f: impl FnMut(&T))

where Self: Sized,

Visit all occurrences of that type inside self, in pre-order traversal.

fn dyn_visit_mut<T: AstVisitable>(&mut self, f: impl FnMut(&mut T))

where Self: Sized,

Visit all occurrences of that type inside self, in pre-order traversal.

impl Clone for Layout

fn clone(&self) -> Layout

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Layout

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, __State: ?Sized> DeserializeState<'de, __State> for Layout

where Size: DeserializeState<'de, __State>, Option<Discriminator>: DeserializeState<'de, __State>, InhabitedPredicate: DeserializeState<'de, __State>, IndexVec<VariantId, Option<VariantLayout>>: DeserializeState<'de, __State>, ReprOptions: Deserialize<'de>,

fn deserialize_state<__D>( __state: &__State, __deserializer: __D, ) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

impl Display for Layout

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'s, V> Drive<'s, V> for Layout

where V: Visitor + Visit<'s, Size> + Visit<'s, Option<Discriminator>> + Visit<'s, InhabitedPredicate> + Visit<'s, IndexVec<VariantId, Option<VariantLayout>>> + Visit<'s, ReprOptions>,

fn drive_inner(&'s self, visitor: &mut V) -> ControlFlow<V::Break>

Call v.visit() on the immediate contents of self.

impl<'s, V> DriveMut<'s, V> for Layout

where V: Visitor + VisitMut<'s, Size> + VisitMut<'s, Option<Discriminator>> + VisitMut<'s, InhabitedPredicate> + VisitMut<'s, IndexVec<VariantId, Option<VariantLayout>>> + VisitMut<'s, ReprOptions>,

fn drive_inner_mut(&'s mut self, visitor: &mut V) -> ControlFlow<V::Break>

Call v.visit() on the immediate contents of self.

impl<'s, V> DriveTwo<'s, V> for Layout

where V: Visitor<Break: Default> + VisitTwo<'s, Size> + VisitTwo<'s, Option<Discriminator>> + VisitTwo<'s, InhabitedPredicate> + VisitTwo<'s, IndexVec<VariantId, Option<VariantLayout>>> + VisitTwo<'s, ReprOptions>,

fn drive_two_inner( &'s self, other: &'s Self, visitor: &mut V, ) -> ControlFlow<V::Break>

Call v.visit() on the immediate contents of self and other, if they correspond. If the values don’t match up, this returns Break(Default::default()).

impl<C: AstFormatter> FmtWithCtx<C> for Layout

fn fmt_with_ctx(&self, ctx: &C, f: &mut Formatter<'_>) -> Result

fn with_ctx<'a>(&'a self, ctx: &'a C) -> WithCtx<'a, C, Self>

Returns a struct that implements Display. This allows the following:

fn to_string_with_ctx(&self, ctx: &C) -> String

impl<__State: ?Sized> SerializeState<__State> for Layout

where Size: SerializeState<__State>, Option<Discriminator>: SerializeState<__State>, InhabitedPredicate: SerializeState<__State>, IndexVec<VariantId, Option<VariantLayout>>: SerializeState<__State>, ReprOptions: Serialize,

fn serialize_state<__S>( &self, __state: &__State, __serializer: __S, ) -> Result<__S::Ok, __S::Error>

where __S: Serializer,