Enum ProjectionElem

pub enum ProjectionElem {
    Deref,
    Field(FieldProjKind, FieldId),
    PtrMetadata,
    Index {
        offset: Box<Operand>,
        from_end: bool,
    },
    Subslice {
        from: Box<Operand>,
        to: Box<Operand>,
        from_end: bool,
    },
}

Note that we don’t have the equivalent of “downcasts”. Downcasts are actually necessary, for instance when initializing enumeration values: the value is initially Bottom, and we need a way of knowing the variant. For example: ((_0 as Right).0: T2) = move _1; In MIR, downcasts always happen before field projections: in our internal language, we thus merge downcasts and field projections.

Variants

Deref

Dereference a shared/mutable reference, a box, or a raw pointer.

Field(FieldProjKind, FieldId)

Projection from ADTs (variants, structures). We allow projections to be used as left-values and right-values. We should never have projections to fields of symbolic variants (they should have been expanded before through a match).

PtrMetadata

A built-in pointer (a reference, raw pointer, or Box) in Rust is always a fat pointer: it contains an address and metadata for the pointed-to place. This metadata is empty for sized types, it’s the length for slices, and the vtable for dyn Trait.

We consider such pointers to be like a struct with two fields; this represent access to the metadata “field”.

Index

MIR imposes that the argument to an index projection be a local variable, meaning that even constant indices into arrays are let-bound as separate variables. We eliminate this variant in a micro-pass for LLBC.

Fields

offset: Box<Operand>

from_end: bool

Subslice

Take a subslice of a slice or array. If from_end is true this is slice[from..slice.len() - to], otherwise this is slice[from..to]. We eliminate this variant in a micro-pass for LLBC.

Fields

from: Box<Operand>

to: Box<Operand>

from_end: bool

Implementations

impl ProjectionElem

pub fn is_deref(&self) -> bool

pub fn is_field(&self) -> bool

pub fn is_ptr_metadata(&self) -> bool

pub fn is_index(&self) -> bool

pub fn is_subslice(&self) -> bool

impl ProjectionElem

pub fn as_deref(&self) -> Option<()>

pub fn as_field(&self) -> Option<(&FieldProjKind, &FieldId)>

pub fn as_ptr_metadata(&self) -> Option<()>

pub fn as_index(&self) -> Option<(&Box<Operand>, &bool)>

pub fn as_subslice(&self) -> Option<(&Box<Operand>, &Box<Operand>, &bool)>

impl ProjectionElem

pub fn as_deref_mut(&mut self) -> Option<()>

pub fn as_field_mut(&mut self) -> Option<(&mut FieldProjKind, &mut FieldId)>

pub fn as_ptr_metadata_mut(&mut self) -> Option<()>

pub fn as_index_mut(&mut self) -> Option<(&mut Box<Operand>, &mut bool)>

pub fn as_subslice_mut( &mut self, ) -> Option<(&mut Box<Operand>, &mut Box<Operand>, &mut bool)>

impl ProjectionElem

pub fn to_deref(self) -> Option<()>

pub fn to_field(self) -> Option<(FieldProjKind, FieldId)>

pub fn to_ptr_metadata(self) -> Option<()>

pub fn to_index(self) -> Option<(Box<Operand>, bool)>

pub fn to_subslice(self) -> Option<(Box<Operand>, Box<Operand>, bool)>

impl ProjectionElem

pub fn variant_name(&self) -> &'static str

impl ProjectionElem

pub fn project_type(&self, krate: &TranslatedCrate, ty: &Ty) -> Result<Ty, ()>

Compute the type obtained when applying the current projection to a place of type ty.

Trait Implementations

impl AstVisitable for ProjectionElem

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 name(&self) -> &'static str

The name of the type, used for debug logging.

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

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))

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

impl BodyVisitable for ProjectionElem

fn drive_body<V: VisitBody>(&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_body_mut<V: VisitBodyMut>( &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 dyn_visit_in_body<T: BodyVisitable>(&self, f: impl FnMut(&T))

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

fn dyn_visit_in_body_mut<T: BodyVisitable>(&mut self, f: impl FnMut(&mut T))

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

impl Clone for ProjectionElem

fn clone(&self) -> ProjectionElem

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ProjectionElem

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ProjectionElem

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

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

where V: Visitor + Visit<'s, FieldProjKind> + Visit<'s, FieldId> + Visit<'s, Box<Operand>>,

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 ProjectionElem

where V: Visitor + VisitMut<'s, FieldProjKind> + VisitMut<'s, FieldId> + VisitMut<'s, Box<Operand>>,

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

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

impl PartialEq for ProjectionElem

fn eq(&self, other: &ProjectionElem) -> bool

Tests for self and other values to be equal, and is used by ==.

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

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

impl Serialize for ProjectionElem

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for ProjectionElem

impl StructuralPartialEq for ProjectionElem