diff options
Diffstat (limited to 'compiler/rustc_borrowck/src/renumber.rs')
-rw-r--r-- | compiler/rustc_borrowck/src/renumber.rs | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/compiler/rustc_borrowck/src/renumber.rs b/compiler/rustc_borrowck/src/renumber.rs new file mode 100644 index 000000000..7a8ce621c --- /dev/null +++ b/compiler/rustc_borrowck/src/renumber.rs @@ -0,0 +1,83 @@ +use rustc_index::vec::IndexVec; +use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin}; +use rustc_middle::mir::visit::{MutVisitor, TyContext}; +use rustc_middle::mir::{Body, Location, Promoted}; +use rustc_middle::ty::subst::SubstsRef; +use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable}; + +/// Replaces all free regions appearing in the MIR with fresh +/// inference variables, returning the number of variables created. +#[instrument(skip(infcx, body, promoted), level = "debug")] +pub fn renumber_mir<'tcx>( + infcx: &InferCtxt<'_, 'tcx>, + body: &mut Body<'tcx>, + promoted: &mut IndexVec<Promoted, Body<'tcx>>, +) { + debug!(?body.arg_count); + + let mut visitor = NllVisitor { infcx }; + + for body in promoted.iter_mut() { + visitor.visit_body(body); + } + + visitor.visit_body(body); +} + +/// Replaces all regions appearing in `value` with fresh inference +/// variables. +#[instrument(skip(infcx), level = "debug")] +pub fn renumber_regions<'tcx, T>(infcx: &InferCtxt<'_, 'tcx>, value: T) -> T +where + T: TypeFoldable<'tcx>, +{ + infcx.tcx.fold_regions(value, |_region, _depth| { + let origin = NllRegionVariableOrigin::Existential { from_forall: false }; + infcx.next_nll_region_var(origin) + }) +} + +struct NllVisitor<'a, 'tcx> { + infcx: &'a InferCtxt<'a, 'tcx>, +} + +impl<'a, 'tcx> NllVisitor<'a, 'tcx> { + fn renumber_regions<T>(&mut self, value: T) -> T + where + T: TypeFoldable<'tcx>, + { + renumber_regions(self.infcx, value) + } +} + +impl<'a, 'tcx> MutVisitor<'tcx> for NllVisitor<'a, 'tcx> { + fn tcx(&self) -> TyCtxt<'tcx> { + self.infcx.tcx + } + + #[instrument(skip(self), level = "debug")] + fn visit_ty(&mut self, ty: &mut Ty<'tcx>, ty_context: TyContext) { + *ty = self.renumber_regions(*ty); + + debug!(?ty); + } + + #[instrument(skip(self), level = "debug")] + fn visit_substs(&mut self, substs: &mut SubstsRef<'tcx>, location: Location) { + *substs = self.renumber_regions(*substs); + + debug!(?substs); + } + + #[instrument(skip(self), level = "debug")] + fn visit_region(&mut self, region: &mut ty::Region<'tcx>, location: Location) { + let old_region = *region; + *region = self.renumber_regions(old_region); + + debug!(?region); + } + + fn visit_const(&mut self, constant: &mut ty::Const<'tcx>, _location: Location) { + *constant = self.renumber_regions(*constant); + } +} |