Enum rustc_middle::mir::syntax::MirPhase
source · pub enum MirPhase {
Built,
Analysis(AnalysisPhase),
Runtime(RuntimePhase),
}
Expand description
Represents the “flavors” of MIR.
All flavors of MIR use the same data structure, but there are some important differences. These differences come in two forms: Dialects and phases.
Dialects represent a stronger distinction than phases. This is because the transitions between
dialects are semantic changes, and therefore technically lowerings between distinct IRs. In
other words, the same Body
might be well-formed for multiple dialects, but
have different semantic meaning and different behavior at runtime.
Each dialect additionally has a number of phases. However, phase changes never involve semantic changes. If some MIR is well-formed both before and after a phase change, it is also guaranteed that it has the same semantic meaning. In this sense, phase changes can only add additional restrictions on what MIR is well-formed.
When adding phases, remember to update MirPhase::phase_index
.
Variants§
Built
The MIR that is generated by MIR building.
The only things that operate on this dialect are unsafeck, the various MIR lints, and const qualifs.
This has no distinct phases.
Analysis(AnalysisPhase)
The MIR used for most analysis.
The only semantic change between analysis and built MIR is constant promotion. In built MIR, sequences of statements that would generally be subject to constant promotion are semantically constants, while in analysis MIR all constants are explicit.
The result of const promotion is available from the mir_promoted
and promoted_mir
queries.
This is the version of MIR used by borrowck and friends.
Runtime(RuntimePhase)
The MIR used for CTFE, optimizations, and codegen.
The semantic changes that occur in the lowering from analysis to runtime MIR are as follows:
- Drops: In analysis MIR,
Drop
terminators represent conditional drops; roughly speaking, if dataflow analysis determines that the place being dropped is uninitialized, the drop will not be executed. The exact semantics of this aren’t written down anywhere, which means they are essentially “what drop elaboration does.” In runtime MIR, the drops are unconditional; when aDrop
terminator is reached, if the type has drop glue that drop glue is always executed. This may be UB if the underlying place is not initialized. - Packed drops: Places might in general be misaligned - in most cases this is UB, the exception
is fields of packed structs. In analysis MIR,
Drop(P)
for aP
that might be misaligned for this reason implicitly movesP
to a temporary before dropping. Runtime MIR has no such rules, and dropping a misaligned place is simply UB. - Unwinding: in analysis MIR, unwinding from a function which may not unwind aborts. In runtime MIR, this is UB.
- Retags: If
-Zmir-emit-retag
is enabled, analysis MIR has “implicit” retags in the same way that Rust itself has them. Where exactly these are is generally subject to change, and so we don’t document this here. Runtime MIR has most retags explicit (though implicit retags can still occur atRvalue::{Ref,AddrOf}
). - Generator bodies: In analysis MIR, locals may actually be behind a pointer that user code has access to. This occurs in generator bodies. Such locals do not behave like other locals, because they eg may be aliased in surprising ways. Runtime MIR has no such special locals - all generator bodies are lowered and so all places that look like locals really are locals.
Also note that the lint pass which reports eg 200_u8 + 200_u8
as an error is run as a part
of analysis to runtime MIR lowering. To ensure lints are reported reliably, this means that
transformations which may suppress such errors should not run on analysis MIR.
Implementations§
Trait Implementations§
source§impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for MirPhase
impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for MirPhase
fn hash_stable( &self, __hcx: &mut StableHashingContext<'__ctx>, __hasher: &mut StableHasher )
source§impl Ord for MirPhase
impl Ord for MirPhase
source§impl PartialEq<MirPhase> for MirPhase
impl PartialEq<MirPhase> for MirPhase
source§impl PartialOrd<MirPhase> for MirPhase
impl PartialOrd<MirPhase> for MirPhase
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moresource§impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for MirPhase
impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for MirPhase
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 MirPhase
impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for MirPhase
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 Copy for MirPhase
impl Eq for MirPhase
impl StructuralEq for MirPhase
impl StructuralPartialEq for MirPhase
Auto Trait Implementations§
impl RefUnwindSafe for MirPhase
impl Send for MirPhase
impl Sync for MirPhase
impl Unpin for MirPhase
impl UnwindSafe for MirPhase
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: 2 bytes
Size for each variant:
Built
: 0 bytesAnalysis
: 1 byteRuntime
: 1 byte