Enum rustc_middle::mir::MirPhase
source · [−]pub enum MirPhase {
Built,
Const,
ConstsPromoted,
DropsLowered,
Deaggregated,
GeneratorsLowered,
Optimized,
}
Expand description
The various “big phases” that MIR goes through.
These phases all describe dialects of MIR. Since all MIR uses the same datastructures, the dialects forbid certain variants or values in certain phases. The sections below summarize the changes, but do not document them thoroughly. The full documentation is found in the appropriate documentation for the thing the change is affecting.
Warning: ordering of variants is significant.
Variants
Built
The dialect of MIR used during all phases before DropsLowered
is the same. This is also
the MIR that analysis such as borrowck uses.
One important thing to remember about the behavior of this section of MIR is that drop terminators (including drop and replace) are conditional. The elaborate drops pass will then replace each instance of a drop terminator with a nop, an unconditional drop, or a drop conditioned on a drop flag. Of course, this means that it is important that the drop elaboration can accurately recognize when things are initialized and when things are de-initialized. That means any code running on this version of MIR must be sure to produce output that drop elaboration can reason about. See the section on the drop terminatorss for more details.
Const
ConstsPromoted
This phase checks the MIR for promotable elements and takes them out of the main MIR body
by creating a new MIR body per promoted element. After this phase (and thus the termination
of the mir_promoted
query), these promoted elements are available in the promoted_mir
query.
DropsLowered
Beginning with this phase, the following variants are disallowed:
TerminatorKind::DropAndReplace
TerminatorKind::FalseUnwind
TerminatorKind::FalseEdge
StatementKind::FakeRead
StatementKind::AscribeUserType
Rvalue::Ref
withBorrowKind::Shallow
And the following variant is allowed:
Furthermore, Drop
now uses explicit drop flags visible in the MIR and reaching a Drop
terminator means that the auto-generated drop glue will be invoked. Also, Copy
operands
are allowed for non-Copy
types.
Deaggregated
Beginning with this phase, the following variant is disallowed:
Rvalue::Aggregate
for anyAggregateKind
exceptArray
And the following variant is allowed:
GeneratorsLowered
Before this phase, generators are in the “source code” form, featuring yield
statements
and such. With this phase change, they are transformed into a proper state machine. Running
optimizations before this change can be potentially dangerous because the source code is to
some extent a “lie.” In particular, yield
terminators effectively make the value of all
locals visible to the caller. This means that dead store elimination before them, or code
motion across them, is not correct in general. This is also exasperated by type checking
having pre-computed a list of the types that it thinks are ok to be live across a yield
point - this is necessary to decide eg whether autotraits are implemented. Introducing new
types across a yield point will lead to ICEs becaues of this.
Beginning with this phase, the following variants are disallowed:
Optimized
Implementations
sourceimpl MirPhase
impl MirPhase
sourcepub fn phase_index(&self) -> usize
pub fn phase_index(&self) -> usize
Gets the index of the current MirPhase within the set of all MirPhase
s.
Trait Implementations
sourceimpl<'__ctx> HashStable<StableHashingContext<'__ctx>> for MirPhase
impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for MirPhase
fn hash_stable(
&self,
__hcx: &mut StableHashingContext<'__ctx>,
__hasher: &mut StableHasher
)
sourceimpl Ord for MirPhase
impl Ord for MirPhase
sourceimpl PartialOrd<MirPhase> for MirPhase
impl PartialOrd<MirPhase> for MirPhase
sourcefn partial_cmp(&self, other: &MirPhase) -> Option<Ordering>
fn partial_cmp(&self, other: &MirPhase) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
1.0.0 · sourcefn lt(&self, other: &Rhs) -> bool
fn lt(&self, other: &Rhs) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
1.0.0 · sourcefn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
sourceimpl<'tcx> TypeFoldable<'tcx> for MirPhase
impl<'tcx> TypeFoldable<'tcx> for MirPhase
sourcefn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
_: &mut F
) -> Result<MirPhase, F::Error>
fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
_: &mut F
) -> Result<MirPhase, F::Error>
Traverses the type in question, typically by calling try_fold_with
on
each field/element. This is true even for types of interest such as
Ty
. This should only be called within TypeFolder
methods, when
non-custom traversals are desired for types of interest. Read more
sourcefn super_visit_with<F: TypeVisitor<'tcx>>(
&self,
_: &mut F
) -> ControlFlow<F::BreakTy>
fn super_visit_with<F: TypeVisitor<'tcx>>(
&self,
_: &mut F
) -> ControlFlow<F::BreakTy>
Traverses the type in question, typically by calling visit_with
on
each field/element. This is true even for types of interest such as
Ty
. This should only be called within TypeVisitor
methods, when
non-custom traversals are desired for types of interest. Read more
sourcefn try_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
folder: &mut F
) -> Result<Self, F::Error>
fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
folder: &mut F
) -> Result<Self, F::Error>
The main entry point for folding. To fold a value t
with a folder f
call: t.try_fold_with(f)
. Read more
sourcefn fold_with<F: TypeFolder<'tcx, Error = !>>(self, folder: &mut F) -> Self
fn fold_with<F: TypeFolder<'tcx, Error = !>>(self, folder: &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
. Read more
sourcefn super_fold_with<F: TypeFolder<'tcx, Error = !>>(self, folder: &mut F) -> Self
fn super_fold_with<F: TypeFolder<'tcx, Error = !>>(self, folder: &mut F) -> Self
A convenient alternative to try_super_fold_with
for use with
infallible folders. Do not override this method, to ensure coherence
with try_super_fold_with
. Read more
sourcefn visit_with<V: TypeVisitor<'tcx>>(
&self,
visitor: &mut V
) -> ControlFlow<V::BreakTy>
fn visit_with<V: TypeVisitor<'tcx>>(
&self,
visitor: &mut V
) -> ControlFlow<V::BreakTy>
The entry point for visiting. To visit a value t
with a visitor v
call: t.visit_with(v)
. Read more
sourcefn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
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. Read more
sourcefn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
Returns true
if this self
has any regions that escape binder
(and
hence are not bound by it). Read more
fn has_escaping_bound_vars(&self) -> bool
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) -> Option<ErrorGuaranteed>
fn has_param_types_or_consts(&self) -> bool
fn has_infer_regions(&self) -> bool
fn has_infer_types(&self) -> bool
fn has_infer_types_or_consts(&self) -> bool
fn needs_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn needs_subst(&self) -> bool
sourcefn has_free_regions(&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. Read more
fn has_erased_regions(&self) -> bool
sourcefn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
True if there are any un-erased free regions.
sourcefn is_global(&self) -> bool
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. Read more
sourcefn has_late_bound_regions(&self) -> bool
fn has_late_bound_regions(&self) -> bool
True if there are any late-bound regions
sourcefn still_further_specializable(&self) -> bool
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. Read more
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
sourceimpl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T where
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T where
T: Copy,
fn allocate_on(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter(
arena: &'a Arena<'tcx>,
iter: impl IntoIterator<Item = T>
) -> &'a mut [T]ⓘNotable traits for &'_ [u8]impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<Ctxt, T> DepNodeParams<Ctxt> for T where
Ctxt: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
impl<Ctxt, T> DepNodeParams<Ctxt> for T where
Ctxt: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
default fn fingerprint_style() -> FingerprintStyle
sourcedefault fn to_fingerprint(&self, tcx: Ctxt) -> Fingerprint
default fn to_fingerprint(&self, tcx: Ctxt) -> 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). Read more
default fn to_debug_str(&self, Ctxt) -> String
sourcedefault fn recover(Ctxt, &DepNode<<Ctxt as DepContext>::DepKind>) -> Option<T>
default fn recover(Ctxt, &DepNode<<Ctxt as DepContext>::DepKind>) -> Option<T>
This method tries to recover the query key from the given 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. Read more
sourceimpl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcefn clone_into(&self, target: &mut T)
fn clone_into(&self, target: &mut T)
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more
impl<'a, T> Captures<'a> for T where
T: ?Sized,
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: 1 byte
Size for each variant:
Built
: 0 bytesConst
: 0 bytesConstsPromoted
: 0 bytesDropsLowered
: 0 bytesDeaggregated
: 0 bytesGeneratorsLowered
: 0 bytesOptimized
: 0 bytes