Struct rustc_const_eval::transform::check_consts::resolver::TransferFunction

struct TransferFunction<'a, 'mir, 'tcx, Q> {
    ccx: &'a ConstCx<'mir, 'tcx>,
    state: &'a mut State,
    _qualif: PhantomData<Q>,
}

A Visitor that propagates qualifs between locals. This defines the transfer function of FlowSensitiveAnalysis.

To account for indirect assignments, data flow conservatively assumes that local becomes qualified immediately after it is borrowed or its address escapes. The borrow must allow for mutation, which includes shared borrows of places with interior mutability. The type of borrowed place must contain the qualif.

Fields

ccx: &'a ConstCx<'mir, 'tcx>

state: &'a mut State

_qualif: PhantomData<Q>

Implementations

impl<'a, 'mir, 'tcx, Q> TransferFunction<'a, 'mir, 'tcx, Q>where
    Q: Qualif,

fn new(ccx: &'a ConstCx<'mir, 'tcx>, state: &'a mut State) -> Self

fn initialize_state(&mut self)

fn assign_qualif_direct(&mut self, place: &Place<'tcx>, value: bool)

fn apply_call_return_effect(
    &mut self,
    _block: BasicBlock,
    return_places: CallReturnPlaces<'_, 'tcx>
)

fn address_of_allows_mutation(&self, _mt: Mutability, _place: Place<'tcx>) -> bool

fn ref_allows_mutation(&self, kind: BorrowKind, place: Place<'tcx>) -> bool

fn shared_borrow_allows_mutation(&self, place: Place<'tcx>) -> bool

& only allow mutation if the borrowed place is !Freeze.

This assumes that it is UB to take the address of a struct field whose type is Freeze, then use pointer arithmetic to derive a pointer to a different field of that same struct whose type is !Freeze. If we decide that this is not UB, we will have to check the type of the borrowed local instead of the borrowed place below. See rust-lang/unsafe-code-guidelines#134.

Trait Implementations

impl<'tcx, Q> Visitor<'tcx> for TransferFunction<'_, '_, 'tcx, Q>where
    Q: Qualif,

fn visit_operand(&mut self, operand: &Operand<'tcx>, location: Location)

fn visit_assign(
    &mut self,
    place: &Place<'tcx>,
    rvalue: &Rvalue<'tcx>,
    location: Location
)

fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location)

fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location)

fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location)

fn visit_body(&mut self, body: &Body<'tcx>)

fn visit_basic_block_data(
    &mut self,
    block: BasicBlock,
    data: &BasicBlockData<'tcx>
)

fn visit_source_scope_data(&mut self, scope_data: &SourceScopeData<'tcx>)

fn visit_assert_message(
    &mut self,
    msg: &AssertKind<Operand<'tcx>>,
    location: Location
)

fn visit_ascribe_user_ty(
    &mut self,
    place: &Place<'tcx>,
    variance: Variance,
    user_ty: &UserTypeProjection,
    location: Location
)

fn visit_coverage(&mut self, coverage: &Coverage, location: Location)

fn visit_retag(&mut self, kind: RetagKind, place: &Place<'tcx>, location: Location)

fn visit_place(
    &mut self,
    place: &Place<'tcx>,
    context: PlaceContext,
    location: Location
)

fn visit_projection(
    &mut self,
    place_ref: PlaceRef<'tcx>,
    context: PlaceContext,
    location: Location
)

fn visit_projection_elem(
    &mut self,
    local: Local,
    proj_base: &[ProjectionElem<Local, Ty<'tcx>, Ty<'tcx>>],
    elem: ProjectionElem<Local, Ty<'tcx>, Ty<'tcx>>,
    context: PlaceContext,
    location: Location
)

fn super_place(
    &mut self,
    place: &Place<'tcx>,
    context: PlaceContext,
    location: Location
)

fn super_projection(
    &mut self,
    place_ref: PlaceRef<'tcx>,
    context: PlaceContext,
    location: Location
)

fn super_projection_elem(
    &mut self,
    _local: Local,
    _proj_base: &[ProjectionElem<Local, Ty<'tcx>, Ty<'tcx>>],
    elem: ProjectionElem<Local, Ty<'tcx>, Ty<'tcx>>,
    _context: PlaceContext,
    location: Location
)

fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location)

fn visit_span(&mut self, span: Span)

fn visit_source_info(&mut self, source_info: &SourceInfo)

fn visit_ty(&mut self, ty: Ty<'tcx>, _: TyContext)

fn visit_user_type_projection(&mut self, ty: &UserTypeProjection)

fn visit_user_type_annotation(
    &mut self,
    index: UserTypeAnnotationIndex,
    ty: &CanonicalUserTypeAnnotation<'tcx>
)

fn visit_region(&mut self, region: Region<'tcx>, _: Location)

fn visit_substs(&mut self, substs: &&'tcx List<GenericArg<'tcx>>, _: Location)

fn visit_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>)

fn visit_var_debug_info(&mut self, var_debug_info: &VarDebugInfo<'tcx>)

fn visit_local(
    &mut self,
    _local: Local,
    _context: PlaceContext,
    _location: Location
)

fn visit_source_scope(&mut self, scope: SourceScope)

fn super_body(&mut self, body: &Body<'tcx>)

fn super_basic_block_data(
    &mut self,
    block: BasicBlock,
    data: &BasicBlockData<'tcx>
)

fn super_source_scope_data(&mut self, scope_data: &SourceScopeData<'tcx>)

fn super_statement(&mut self, statement: &Statement<'tcx>, location: Location)

fn super_assign(
    &mut self,
    place: &Place<'tcx>,
    rvalue: &Rvalue<'tcx>,
    location: Location
)

fn super_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location)

fn super_assert_message(
    &mut self,
    msg: &AssertKind<Operand<'tcx>>,
    location: Location
)

fn super_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location)

fn super_operand(&mut self, operand: &Operand<'tcx>, location: Location)

fn super_ascribe_user_ty(
    &mut self,
    place: &Place<'tcx>,
    _variance: Variance,
    user_ty: &UserTypeProjection,
    location: Location
)

fn super_coverage(&mut self, _coverage: &Coverage, _location: Location)

fn super_retag(
    &mut self,
    _kind: RetagKind,
    place: &Place<'tcx>,
    location: Location
)

fn super_local_decl(&mut self, local: Local, local_decl: &LocalDecl<'tcx>)

fn super_var_debug_info(&mut self, var_debug_info: &VarDebugInfo<'tcx>)

fn super_source_scope(&mut self, _scope: SourceScope)

fn super_constant(&mut self, constant: &Constant<'tcx>, location: Location)

fn super_span(&mut self, _span: Span)

fn super_source_info(&mut self, source_info: &SourceInfo)

fn super_user_type_projection(&mut self, _ty: &UserTypeProjection)

fn super_user_type_annotation(
    &mut self,
    _index: UserTypeAnnotationIndex,
    ty: &CanonicalUserTypeAnnotation<'tcx>
)

fn super_ty(&mut self, _ty: Ty<'tcx>)

fn super_region(&mut self, _region: Region<'tcx>)

fn super_substs(&mut self, _substs: &&'tcx List<GenericArg<'tcx>>)

fn visit_location(&mut self, body: &Body<'tcx>, location: Location)

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes