| // Copyright 2017 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| use rustc::ty::subst::Substs; |
| use rustc::ty::{self, ClosureSubsts, GeneratorSubsts, Ty, TypeFoldable}; |
| use rustc::mir::{BasicBlock, Location, Mir, Statement, StatementKind, UserTypeAnnotation}; |
| use rustc::mir::visit::{MutVisitor, TyContext}; |
| use rustc::infer::{InferCtxt, NLLRegionVariableOrigin}; |
| |
| /// Replaces all free regions appearing in the MIR with fresh |
| /// inference variables, returning the number of variables created. |
| pub fn renumber_mir<'tcx>(infcx: &InferCtxt<'_, '_, 'tcx>, mir: &mut Mir<'tcx>) { |
| debug!("renumber_mir()"); |
| debug!("renumber_mir: mir.arg_count={:?}", mir.arg_count); |
| |
| let mut visitor = NLLVisitor { infcx }; |
| visitor.visit_mir(mir); |
| } |
| |
| /// Replaces all regions appearing in `value` with fresh inference |
| /// variables. |
| pub fn renumber_regions<'tcx, T>( |
| infcx: &InferCtxt<'_, '_, 'tcx>, |
| value: &T, |
| ) -> T |
| where |
| T: TypeFoldable<'tcx>, |
| { |
| debug!("renumber_regions(value={:?})", value); |
| |
| infcx |
| .tcx |
| .fold_regions(value, &mut false, |_region, _depth| { |
| let origin = NLLRegionVariableOrigin::Existential; |
| infcx.next_nll_region_var(origin) |
| }) |
| } |
| |
| struct NLLVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> { |
| infcx: &'a InferCtxt<'a, 'gcx, 'tcx>, |
| } |
| |
| impl<'a, 'gcx, 'tcx> NLLVisitor<'a, 'gcx, 'tcx> { |
| fn renumber_regions<T>(&mut self, value: &T) -> T |
| where |
| T: TypeFoldable<'tcx>, |
| { |
| renumber_regions(self.infcx, value) |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'gcx, 'tcx> { |
| fn visit_ty(&mut self, ty: &mut Ty<'tcx>, ty_context: TyContext) { |
| debug!("visit_ty(ty={:?}, ty_context={:?})", ty, ty_context); |
| |
| *ty = self.renumber_regions(ty); |
| |
| debug!("visit_ty: ty={:?}", ty); |
| } |
| |
| fn visit_user_type_annotation(&mut self, _ty: &mut UserTypeAnnotation<'tcx>) { |
| // User type annotations represent the types that the user |
| // wrote in the progarm. We don't want to erase the regions |
| // from these types: rather, we want to add them as |
| // constraints at type-check time. |
| debug!("visit_user_type_annotation: skipping renumber"); |
| } |
| |
| fn visit_substs(&mut self, substs: &mut &'tcx Substs<'tcx>, location: Location) { |
| debug!("visit_substs(substs={:?}, location={:?})", substs, location); |
| |
| *substs = self.renumber_regions(&{ *substs }); |
| |
| debug!("visit_substs: substs={:?}", substs); |
| } |
| |
| fn visit_region(&mut self, region: &mut ty::Region<'tcx>, location: Location) { |
| debug!("visit_region(region={:?}, location={:?})", region, location); |
| |
| let old_region = *region; |
| *region = self.renumber_regions(&old_region); |
| |
| debug!("visit_region: region={:?}", region); |
| } |
| |
| fn visit_const(&mut self, constant: &mut &'tcx ty::Const<'tcx>, _location: Location) { |
| *constant = self.renumber_regions(&*constant); |
| } |
| |
| fn visit_generator_substs(&mut self, |
| substs: &mut GeneratorSubsts<'tcx>, |
| location: Location) { |
| debug!( |
| "visit_generator_substs(substs={:?}, location={:?})", |
| substs, |
| location, |
| ); |
| |
| *substs = self.renumber_regions(substs); |
| |
| debug!("visit_generator_substs: substs={:?}", substs); |
| } |
| |
| fn visit_closure_substs(&mut self, substs: &mut ClosureSubsts<'tcx>, location: Location) { |
| debug!( |
| "visit_closure_substs(substs={:?}, location={:?})", |
| substs, |
| location |
| ); |
| |
| *substs = self.renumber_regions(substs); |
| |
| debug!("visit_closure_substs: substs={:?}", substs); |
| } |
| |
| fn visit_statement( |
| &mut self, |
| block: BasicBlock, |
| statement: &mut Statement<'tcx>, |
| location: Location, |
| ) { |
| if let StatementKind::EndRegion(_) = statement.kind { |
| statement.kind = StatementKind::Nop; |
| } |
| self.super_statement(block, statement, location); |
| } |
| } |