Struct rustc_target::abi::TyAndLayout

pub struct TyAndLayout<'a, Ty> {
    pub ty: Ty,
    pub layout: Layout<'a>,
}

The layout of a type, alongside the type itself. Provides various type traversal APIs (e.g., recursing into fields).

Note that the layout is NOT guaranteed to always be identical to that obtained from layout_of(ty), as we need to produce layouts for which Rust types do not exist, such as enum variants or synthetic fields of enums (i.e., discriminants) and fat pointers.

Fields

ty: Ty

layout: Layout<'a>

Implementations

impl<'a, Ty> TyAndLayout<'a, Ty>

fn is_aggregate(&self) -> bool

pub fn homogeneous_aggregate<C>(
    &self,
    cx: &C
) -> Result<HomogeneousAggregate, Heterogeneous>where
    Ty: TyAbiInterface<'a, C> + Copy,

Returns Homogeneous if this layout is an aggregate containing fields of only a single type (e.g., (u32, u32)). Such aggregates are often special-cased in ABIs.

Note: We generally ignore fields of zero-sized type when computing this value (see #56877).

This is public so that it can be used in unit tests, but should generally only be relevant to the ABI details of specific targets.

impl<'a, Ty> TyAndLayout<'a, Ty>

pub fn for_variant<C>(self, cx: &C, variant_index: VariantIdx) -> Selfwhere
    Ty: TyAbiInterface<'a, C>,

pub fn field<C>(self, cx: &C, i: usize) -> Selfwhere
    Ty: TyAbiInterface<'a, C>,

pub fn pointee_info_at<C>(self, cx: &C, offset: Size) -> Option<PointeeInfo>where
    Ty: TyAbiInterface<'a, C>,

pub fn is_single_fp_element<C>(self, cx: &C) -> boolwhere
    Ty: TyAbiInterface<'a, C>,
    C: HasDataLayout,

pub fn is_adt<C>(self) -> boolwhere
    Ty: TyAbiInterface<'a, C>,

pub fn is_never<C>(self) -> boolwhere
    Ty: TyAbiInterface<'a, C>,

pub fn is_tuple<C>(self) -> boolwhere
    Ty: TyAbiInterface<'a, C>,

pub fn is_unit<C>(self) -> boolwhere
    Ty: TyAbiInterface<'a, C>,

impl<'a, Ty> TyAndLayout<'a, Ty>

pub fn is_unsized(&self) -> bool

Returns true if the layout corresponds to an unsized type.

pub fn is_zst(&self) -> bool

Returns true if the type is a ZST and not unsized.

pub fn might_permit_raw_init<C>(self, cx: &C, init_kind: InitKind) -> boolwhere
    Self: Copy,
    Ty: TyAbiInterface<'a, C>,
    C: HasDataLayout,

Determines if this type permits “raw” initialization by just transmuting some memory into an instance of T.

init_kind indicates if the memory is zero-initialized or left uninitialized.

This code is intentionally conservative, and will not detect

• zero init of an enum whose 0 variant does not allow zero initialization
• making uninitialized types who have a full valid range (ints, floats, raw pointers)
• Any form of invalid value being made inside an array (unless the value is uninhabited)

A strict form of these checks that uses const evaluation exists in rustc_const_eval::might_permit_raw_init, and a tracking issue for making these checks stricter is https://github.com/rust-lang/rust/issues/66151.

FIXME: Once all the conservatism is removed from here, and the checks are ran by default, we can use the const evaluation checks always instead.

Trait Implementations

impl<'a, Ty: Clone> Clone for TyAndLayout<'a, Ty>

fn clone(&self) -> TyAndLayout<'a, Ty>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'a, Ty: Debug> Debug for TyAndLayout<'a, Ty>

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

Formats the value using the given formatter.

impl<'a, Ty> Deref for TyAndLayout<'a, Ty>

type Target = &'a LayoutS<'a>

The resulting type after dereferencing.

fn deref(&self) -> &&'a LayoutS<'a>

Dereferences the value.

impl<'a, Ty: Hash> Hash for TyAndLayout<'a, Ty>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,

Feeds a slice of this type into the given Hasher.

impl<'a, Ty, __CTX> HashStable<__CTX> for TyAndLayout<'a, Ty>where
    __CTX: HashStableContext,
    Ty: HashStable<__CTX>,

fn hash_stable(&self, __hcx: &mut __CTX, __hasher: &mut StableHasher)

impl<'a, Ty: PartialEq> PartialEq<TyAndLayout<'a, Ty>> for TyAndLayout<'a, Ty>

fn eq(&self, other: &TyAndLayout<'a, Ty>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, Ty: Copy> Copy for TyAndLayout<'a, Ty>

impl<'a, Ty: Eq> Eq for TyAndLayout<'a, Ty>

impl<'a, Ty> StructuralEq for TyAndLayout<'a, Ty>

impl<'a, Ty> StructuralPartialEq for TyAndLayout<'a, Ty>

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.