Enum rustc_middle::mir::ConstValue
source · pub enum ConstValue<'tcx> {
Scalar(Scalar),
ZeroSized,
Slice {
data: ConstAllocation<'tcx>,
meta: u64,
},
Indirect {
alloc_id: AllocId,
offset: Size,
},
}
Expand description
Represents a constant value in Rust. Scalar
and Slice
are optimizations for
array length computations, enum discriminants and the pattern matching logic.
Variants§
Scalar(Scalar)
Used for types with layout::abi::Scalar
ABI.
Not using the enum Value
to encode that this must not be Uninit
.
ZeroSized
Only for ZSTs.
Slice
Fields
data: ConstAllocation<'tcx>
The allocation storing the slice contents. This always points to the beginning of the allocation.
Used for references to unsized types with slice tail.
This is worth an optimized representation since Rust has literals of type &str
and
&[u8]
. Not having to indirect those through an AllocId
(or two, if we used Indirect
)
has shown measurable performance improvements on stress tests. We then reuse this
optimization for slice-tail types more generally during valtree-to-constval conversion.
Indirect
Fields
alloc_id: AllocId
The backing memory of the value. May contain more memory than needed for just the value if this points into some other larger ConstValue.
We use an AllocId
here instead of a ConstAllocation<'tcx>
to make sure that when a
raw constant (which is basically just an AllocId
) is turned into a ConstValue
and
back, we can preserve the original AllocId
.
A value not representable by the other variants; needs to be stored in-memory.
Must not be used for scalars or ZST, but having &str
or other slices in this variant is fine.
Implementations§
source§impl<'tcx> ConstValue<'tcx>
impl<'tcx> ConstValue<'tcx>
pub fn try_to_scalar(&self) -> Option<Scalar<AllocId>>
pub fn try_to_scalar_int(&self) -> Option<ScalarInt>
pub fn try_to_bits(&self, size: Size) -> Option<u128>
pub fn try_to_bool(&self) -> Option<bool>
pub fn try_to_target_usize(&self, tcx: TyCtxt<'tcx>) -> Option<u64>
pub fn try_to_bits_for_ty( &self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, ty: Ty<'tcx> ) -> Option<u128>
pub fn from_bool(b: bool) -> Self
pub fn from_u64(i: u64) -> Self
pub fn from_u128(i: u128) -> Self
pub fn from_target_usize(i: u64, cx: &impl HasDataLayout) -> Self
sourcepub fn try_get_slice_bytes_for_diagnostics(
&self,
tcx: TyCtxt<'tcx>
) -> Option<&'tcx [u8]>
pub fn try_get_slice_bytes_for_diagnostics( &self, tcx: TyCtxt<'tcx> ) -> Option<&'tcx [u8]>
Must only be called on constants of type &str
or &[u8]
!
Trait Implementations§
source§impl<'tcx> Clone for ConstValue<'tcx>
impl<'tcx> Clone for ConstValue<'tcx>
source§fn clone(&self) -> ConstValue<'tcx>
fn clone(&self) -> ConstValue<'tcx>
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl<'tcx> Debug for ConstValue<'tcx>
impl<'tcx> Debug for ConstValue<'tcx>
source§impl<'tcx> Hash for ConstValue<'tcx>
impl<'tcx> Hash for ConstValue<'tcx>
source§impl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for ConstValue<'tcx>
impl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for ConstValue<'tcx>
fn hash_stable( &self, __hcx: &mut StableHashingContext<'__ctx>, __hasher: &mut StableHasher )
source§impl<'tcx, '__lifted> Lift<'__lifted> for ConstValue<'tcx>
impl<'tcx, '__lifted> Lift<'__lifted> for ConstValue<'tcx>
type Lifted = ConstValue<'__lifted>
fn lift_to_tcx(self, __tcx: TyCtxt<'__lifted>) -> Option<ConstValue<'__lifted>>
source§impl<'tcx> PartialEq<ConstValue<'tcx>> for ConstValue<'tcx>
impl<'tcx> PartialEq<ConstValue<'tcx>> for ConstValue<'tcx>
source§fn eq(&self, other: &ConstValue<'tcx>) -> bool
fn eq(&self, other: &ConstValue<'tcx>) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ConstValue<'tcx>
impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ConstValue<'tcx>
source§fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
self,
_: &mut F
) -> Result<Self, F::Error>
fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>
source§impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for ConstValue<'tcx>
impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for ConstValue<'tcx>
source§fn visit_with<F: TypeVisitor<TyCtxt<'tcx>>>(
&self,
_: &mut F
) -> ControlFlow<F::BreakTy>
fn visit_with<F: TypeVisitor<TyCtxt<'tcx>>>( &self, _: &mut F ) -> ControlFlow<F::BreakTy>
impl<'tcx> Copy for ConstValue<'tcx>
impl<'tcx> Eq for ConstValue<'tcx>
impl<'tcx> StructuralEq for ConstValue<'tcx>
impl<'tcx> StructuralPartialEq for ConstValue<'tcx>
Auto Trait Implementations§
impl<'tcx> RefUnwindSafe for ConstValue<'tcx>
impl<'tcx> Send for ConstValue<'tcx>
impl<'tcx> Sync for ConstValue<'tcx>
impl<'tcx> Unpin for ConstValue<'tcx>
impl<'tcx> UnwindSafe for ConstValue<'tcx>
Blanket Implementations§
source§impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere T: Copy,
fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T> ) -> &'a mut [T]
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
source§impl<Tcx, T> DepNodeParams<Tcx> for Twhere
Tcx: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
impl<Tcx, T> DepNodeParams<Tcx> for Twhere Tcx: DepContext, T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
default fn fingerprint_style() -> FingerprintStyle
source§default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_debug_str(&self, _: Tcx) -> String
source§default fn recover(_: Tcx, _: &DepNode) -> Option<T>
default fn recover(_: Tcx, _: &DepNode) -> Option<T>
DepNode
,
something which is needed when forcing DepNode
s 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.source§impl<P> IntoQueryParam<P> for P
impl<P> IntoQueryParam<P> for P
fn into_query_param(self) -> P
source§impl<'tcx, T> IsSuggestable<'tcx> for Twhere
T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,
impl<'tcx, T> IsSuggestable<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,
source§impl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
source§impl<'tcx, T> ToPredicate<'tcx, T> for T
impl<'tcx, T> ToPredicate<'tcx, T> for T
fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T
source§impl<'tcx, T> TypeVisitableExt<'tcx> for Twhere
T: TypeVisitable<TyCtxt<'tcx>>,
impl<'tcx, T> TypeVisitableExt<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>>,
source§fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
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.source§fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
true
if this type has any regions that escape binder
(and
hence are not bound by it).source§fn has_escaping_bound_vars(&self) -> bool
fn has_escaping_bound_vars(&self) -> bool
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 morefn has_type_flags(&self, flags: TypeFlags) -> bool
fn has_projections(&self) -> bool
fn has_inherent_projections(&self) -> bool
fn has_opaque_types(&self) -> bool
fn has_generators(&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 has_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn has_non_region_placeholders(&self) -> bool
fn has_param(&self) -> bool
source§fn has_free_regions(&self) -> bool
fn has_free_regions(&self) -> bool
fn has_erased_regions(&self) -> bool
source§fn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
source§fn is_global(&self) -> bool
fn is_global(&self) -> bool
source§fn has_late_bound_regions(&self) -> bool
fn has_late_bound_regions(&self) -> bool
source§fn has_non_region_late_bound(&self) -> bool
fn has_non_region_late_bound(&self) -> bool
source§fn has_late_bound_vars(&self) -> bool
fn has_late_bound_vars(&self) -> bool
source§fn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
impl
specialization.source§impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
impl<Tcx, T> Value<Tcx> for Twhere Tcx: DepContext,
default fn from_cycle_error( tcx: Tcx, cycle: &[QueryInfo], _guar: ErrorGuaranteed ) -> T
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: 24 bytes
Size for each variant:
Scalar
: 24 bytesZeroSized
: 0 bytesSlice
: 24 bytesIndirect
: 24 bytes