Enum rustc_middle::mir::interpret::value::Scalar

pub enum Scalar<Prov = AllocId> {
    Int(ScalarInt),
    Ptr(Pointer<Prov>, u8),
}

A Scalar represents an immediate, primitive value existing outside of a memory::Allocation. It is in many ways like a small chunk of an Allocation, up to 16 bytes in size. Like a range of bytes in an Allocation, a Scalar can either represent the raw bytes of a simple value or a pointer into another Allocation

These variants would be private if there was a convenient way to achieve that in Rust. Do not match on a Scalar! Use the various to_* methods instead.

Variants

Int(ScalarInt)

The raw bytes of a simple value.

Ptr(Pointer<Prov>, u8)

A pointer.

We also store the size of the pointer, such that a Scalar always knows how big it is. The size is always the pointer size of the current target, but this is not information that we always have readily available.

Implementations

impl<Prov> Scalar<Prov>

pub fn from_pointer(ptr: Pointer<Prov>, cx: &impl HasDataLayout) -> Self

pub fn from_maybe_pointer(
    ptr: Pointer<Option<Prov>>,
    cx: &impl HasDataLayout
) -> Self

Create a Scalar from a pointer with an Option<_> provenance (where None represents a plain integer / “invalid” pointer).

pub fn null_ptr(cx: &impl HasDataLayout) -> Self

pub fn from_bool(b: bool) -> Self

pub fn from_char(c: char) -> Self

pub fn try_from_uint(i: impl Into<u128>, size: Size) -> Option<Self>

pub fn from_uint(i: impl Into<u128>, size: Size) -> Self

pub fn from_u8(i: u8) -> Self

pub fn from_u16(i: u16) -> Self

pub fn from_u32(i: u32) -> Self

pub fn from_u64(i: u64) -> Self

pub fn from_machine_usize(i: u64, cx: &impl HasDataLayout) -> Self

pub fn try_from_int(i: impl Into<i128>, size: Size) -> Option<Self>

pub fn from_int(i: impl Into<i128>, size: Size) -> Self

pub fn from_i32(i: i32) -> Self

pub fn from_i64(i: i64) -> Self

pub fn from_machine_isize(i: i64, cx: &impl HasDataLayout) -> Self

pub fn from_f32(f: Single) -> Self

pub fn from_f64(f: Double) -> Self

pub fn to_bits_or_ptr_internal(
    self,
    target_size: Size
) -> Result<Either<u128, Pointer<Prov>>, ScalarSizeMismatch>

This is almost certainly not the method you want! You should dispatch on the type and use to_{u8,u16,...}/scalar_to_ptr to perform ptr-to-int / int-to-ptr casts as needed.

This method only exists for the benefit of low-level operations that truly need to treat the scalar in whatever form it is.

This throws UB (instead of ICEing) on a size mismatch since size mismatches can arise in Miri when someone declares a function that we shim (such as malloc) with a wrong type.

impl<'tcx, Prov: Provenance> Scalar<Prov>

pub fn to_pointer(
    self,
    cx: &impl HasDataLayout
) -> InterpResult<'tcx, Pointer<Option<Prov>>>

pub fn try_to_int(self) -> Result<ScalarInt, Scalar<AllocId>>

Fundamental scalar-to-int (cast) operation. Many convenience wrappers exist below, that you likely want to use instead.

Will perform ptr-to-int casts if needed and possible. If that fails, we know the offset is relative, so we return an “erased” Scalar (which is useful for error messages but not much else).

pub fn assert_int(self) -> ScalarInt

pub fn to_bits(self, target_size: Size) -> InterpResult<'tcx, u128>

This throws UB (instead of ICEing) on a size mismatch since size mismatches can arise in Miri when someone declares a function that we shim (such as malloc) with a wrong type.

pub fn assert_bits(self, target_size: Size) -> u128

pub fn to_bool(self) -> InterpResult<'tcx, bool>

pub fn to_char(self) -> InterpResult<'tcx, char>

pub fn to_uint(self, size: Size) -> InterpResult<'tcx, u128>

Converts the scalar to produce an unsigned integer of the given size. Fails if the scalar is a pointer.

pub fn to_u8(self) -> InterpResult<'tcx, u8>

Converts the scalar to produce a u8. Fails if the scalar is a pointer.

pub fn to_u16(self) -> InterpResult<'tcx, u16>

Converts the scalar to produce a u16. Fails if the scalar is a pointer.

pub fn to_u32(self) -> InterpResult<'tcx, u32>

Converts the scalar to produce a u32. Fails if the scalar is a pointer.

pub fn to_u64(self) -> InterpResult<'tcx, u64>

Converts the scalar to produce a u64. Fails if the scalar is a pointer.

pub fn to_u128(self) -> InterpResult<'tcx, u128>

Converts the scalar to produce a u128. Fails if the scalar is a pointer.

pub fn to_machine_usize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, u64>

Converts the scalar to produce a machine-pointer-sized unsigned integer. Fails if the scalar is a pointer.

pub fn to_int(self, size: Size) -> InterpResult<'tcx, i128>

Converts the scalar to produce a signed integer of the given size. Fails if the scalar is a pointer.

pub fn to_i8(self) -> InterpResult<'tcx, i8>

Converts the scalar to produce an i8. Fails if the scalar is a pointer.

pub fn to_i16(self) -> InterpResult<'tcx, i16>

Converts the scalar to produce an i16. Fails if the scalar is a pointer.

pub fn to_i32(self) -> InterpResult<'tcx, i32>

Converts the scalar to produce an i32. Fails if the scalar is a pointer.

pub fn to_i64(self) -> InterpResult<'tcx, i64>

Converts the scalar to produce an i64. Fails if the scalar is a pointer.

pub fn to_i128(self) -> InterpResult<'tcx, i128>

Converts the scalar to produce an i128. Fails if the scalar is a pointer.

pub fn to_machine_isize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, i64>

Converts the scalar to produce a machine-pointer-sized signed integer. Fails if the scalar is a pointer.

pub fn to_f32(self) -> InterpResult<'tcx, Single>

pub fn to_f64(self) -> InterpResult<'tcx, Double>

Trait Implementations

impl<Prov: Clone> Clone for Scalar<Prov>

fn clone(&self) -> Scalar<Prov>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<Prov: Provenance> Debug for Scalar<Prov>

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

Formats the value using the given formatter.

impl<'tcx, Prov, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for Scalar<Prov>where
    Prov: Decodable<__D>,

fn decode(__decoder: &mut __D) -> Self

impl<Prov: Provenance> Display for Scalar<Prov>

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

Formats the value using the given formatter.

impl<'tcx, Prov, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for Scalar<Prov>where
    Prov: Encodable<__E>,

fn encode(&self, __encoder: &mut __E)

impl<Prov> From<IeeeFloat<DoubleS>> for Scalar<Prov>

fn from(f: Double) -> Self

Converts to this type from the input type.

impl<Prov> From<IeeeFloat<SingleS>> for Scalar<Prov>

fn from(f: Single) -> Self

Converts to this type from the input type.

impl<Prov> From<ScalarInt> for Scalar<Prov>

fn from(ptr: ScalarInt) -> Self

Converts to this type from the input type.

impl<Prov: Hash> Hash for Scalar<Prov>

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,
    Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'__ctx, Prov> HashStable<StableHashingContext<'__ctx>> for Scalar<Prov>where
    Prov: HashStable<StableHashingContext<'__ctx>>,

fn hash_stable(
    &self,
    __hcx: &mut StableHashingContext<'__ctx>,
    __hasher: &mut StableHasher
)

impl<'tcx> Lift<'tcx> for Scalar

type Lifted = Scalar<AllocId>

fn lift_to_tcx(self, _: TyCtxt<'tcx>) -> Option<Self>

impl<Prov: Provenance> LowerHex for Scalar<Prov>

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

Formats the value using the given formatter.

impl<Prov: PartialEq> PartialEq<Scalar<Prov>> for Scalar<Prov>

fn eq(&self, other: &Scalar<Prov>) -> 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<'tcx> TypeFoldable<'tcx> for Scalar

fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
    self,
    _: &mut F
) -> Result<Self, F::Error>

The entry point for folding. To fold a value t with a folder f call: t.try_fold_with(f).

fn fold_with<F: TypeFolder<'tcx>>(self, _: &mut F) -> Self

A convenient alternative to try_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_fold_with.

impl<'tcx> TypeVisitable<'tcx> for Scalar

fn visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> ControlFlow<F::BreakTy>

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v).

fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool

Returns true if self has any late-bound regions that are either bound by binder or bound by some binder outside of binder. If binder is ty::INNERMOST, this indicates whether there are any late-bound regions that appear free.

fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool

Returns true if this type has any regions that escape binder (and hence are not bound by it).

fn has_escaping_bound_vars(&self) -> bool

Return true if this type has regions that are not a part of the type. For example, for<'a> fn(&'a i32) return false, while fn(&'a i32) would return true. The latter can occur when traversing through the former.

fn has_type_flags(&self, flags: TypeFlags) -> bool

fn has_projections(&self) -> bool

fn has_opaque_types(&self) -> bool

fn references_error(&self) -> bool

fn error_reported(&self) -> Result<(), ErrorGuaranteed>

fn has_non_region_param(&self) -> bool

fn has_infer_regions(&self) -> bool

fn has_infer_types(&self) -> bool

fn has_non_region_infer(&self) -> bool

fn needs_infer(&self) -> bool

fn has_placeholders(&self) -> bool

fn needs_subst(&self) -> bool

fn has_free_regions(&self) -> bool

“Free” regions in this context means that it has any region that is not (a) erased or (b) late-bound.

fn has_erased_regions(&self) -> bool

fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.

fn is_global(&self) -> bool

Indicates whether this value references only ‘global’ generic parameters that are the same regardless of what fn we are in. This is used for caching.

fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions

fn still_further_specializable(&self) -> bool

Indicates whether this value still has parameters/placeholders/inference variables which could be replaced later, in a way that would change the results of impl specialization.

impl<Prov: Copy> Copy for Scalar<Prov>

impl<Prov: Eq> Eq for Scalar<Prov>

impl<Prov> StructuralEq for Scalar<Prov>

impl<Prov> StructuralPartialEq for Scalar<Prov>

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.