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

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§

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Int(ScalarInt)

The raw bytes of a simple value.

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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§

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impl<Prov> Scalar<Prov>

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

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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).

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

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pub fn from_bool(b: bool) -> Self

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pub fn from_char(c: char) -> Self

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

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

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pub fn from_u8(i: u8) -> Self

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pub fn from_u16(i: u16) -> Self

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pub fn from_u32(i: u32) -> Self

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pub fn from_u64(i: u64) -> Self

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

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

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

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pub fn from_i32(i: i32) -> Self

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pub fn from_i64(i: i64) -> Self

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

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pub fn from_f32(f: Single) -> Self

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pub fn from_f64(f: Double) -> Self

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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.

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

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

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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).

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pub fn assert_int(self) -> ScalarInt

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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.

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

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

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

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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.

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

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

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

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

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

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

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

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

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

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

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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.

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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.

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

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

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

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

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

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

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

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

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

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

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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.

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

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

Trait Implementations§

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

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

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<Prov: Provenance> Debug for Scalar<Prov>

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

Formats the value using the given formatter. Read more
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impl<'tcx, Prov, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for Scalar<Prov>where
    Prov: Decodable<__D>,

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

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

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

Formats the value using the given formatter. Read more
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impl<'tcx, Prov, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for Scalar<Prov>where
    Prov: Encodable<__E>,

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

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

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fn from(f: Double) -> Self

Converts to this type from the input type.
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impl<Prov> From<IeeeFloat<SingleS>> for Scalar<Prov>

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fn from(f: Single) -> Self

Converts to this type from the input type.
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impl<Prov> From<ScalarInt> for Scalar<Prov>

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fn from(ptr: ScalarInt) -> Self

Converts to this type from the input type.
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impl<Prov: Hash> Hash for Scalar<Prov>

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

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'__ctx, Prov> HashStable<StableHashingContext<'__ctx>> for Scalar<Prov>where
    Prov: HashStable<StableHashingContext<'__ctx>>,

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

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

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type Lifted = Scalar<AllocId>

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

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

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

Formats the value using the given formatter.
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impl<Prov: PartialEq> PartialEq<Scalar<Prov>> for Scalar<Prov>

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fn eq(&self, other: &Scalar<Prov>) -> bool

This method tests for self and other values to be equal, and is used by ==.
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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.
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impl<'tcx> TypeFoldable<'tcx> for Scalar

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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). Read more
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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.
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impl<'tcx> TypeVisitable<'tcx> for Scalar

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

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fn has_projections(&self) -> bool

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fn has_opaque_types(&self) -> bool

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fn has_generators(&self) -> bool

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fn references_error(&self) -> bool

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

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fn has_non_region_param(&self) -> bool

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fn has_infer_regions(&self) -> bool

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fn has_infer_types(&self) -> bool

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fn has_non_region_infer(&self) -> bool

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fn needs_infer(&self) -> bool

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fn has_placeholders(&self) -> bool

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fn needs_subst(&self) -> bool

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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.
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fn has_erased_regions(&self) -> bool

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fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.
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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.
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fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions
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fn has_non_region_late_bound(&self) -> bool

True if there are any late-bound non-region variables
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fn has_late_bound_vars(&self) -> bool

True if there are any late-bound variables
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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.
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impl<Prov: Copy> Copy for Scalar<Prov>

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impl<Prov: Eq> Eq for Scalar<Prov>

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impl<Prov> StructuralEq for Scalar<Prov>

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impl<Prov> StructuralPartialEq for Scalar<Prov>

Auto Trait Implementations§

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impl<Prov> RefUnwindSafe for Scalar<Prov>where
    Prov: RefUnwindSafe,

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impl<Prov> Send for Scalar<Prov>where
    Prov: Send,

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impl<Prov> Sync for Scalar<Prov>where
    Prov: Sync,

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impl<Prov> Unpin for Scalar<Prov>where
    Prov: Unpin,

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impl<Prov> UnwindSafe for Scalar<Prov>where
    Prov: UnwindSafe,

Blanket Implementations§

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impl<T> Any for Twhere
    T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
    T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = T>
) -> &'a mut [T]

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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<Tcx, T> DepNodeParams<Tcx> for Twhere
    Tcx: DepContext,
    T: for<'a> HashStable<StableHashingContext<'a>> + Debug,

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default fn fingerprint_style() -> FingerprintStyle

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default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint

This method turns the parameters of a DepNodeConstructor into an opaque Fingerprint to be used in DepNode. Not all DepNodeParams support being turned into a Fingerprint (they don’t need to if the corresponding DepNode is anonymous).
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default fn to_debug_str(&self, _: Tcx) -> String

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default fn recover(
    _: Tcx,
    _: &DepNode<<Tcx as DepContext>::DepKind>
) -> Option<T>

This method tries to recover the query key from the given DepNode, something which is needed when forcing DepNodes during red-green evaluation. The query system will only call this method if fingerprint_style() is not FingerprintStyle::Opaque. It is always valid to return None here, in which case incremental compilation will treat the query as having changed instead of forcing it.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, R> InternIteratorElement<T, R> for T

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type Output = R

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fn intern_with<I, F>(iter: I, f: F) -> <T as InternIteratorElement<T, R>>::Outputwhere
    I: Iterator<Item = T>,
    F: FnOnce(&[T]) -> R,

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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impl<T> ToOwned for Twhere
    T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<'tcx, T> ToPredicate<'tcx, T> for T

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fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T

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impl<T> ToString for Twhere
    T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<Tcx, T, D> Value<Tcx, D> for Twhere
    Tcx: DepContext,
    D: DepKind,

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default fn from_cycle_error(tcx: Tcx, _: &[QueryInfo<D>]) -> T

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.