diff options
Diffstat (limited to 'compiler/rustc_borrowck/src/dataflow.rs')
| -rw-r--r-- | compiler/rustc_borrowck/src/dataflow.rs | 132 |
1 files changed, 67 insertions, 65 deletions
diff --git a/compiler/rustc_borrowck/src/dataflow.rs b/compiler/rustc_borrowck/src/dataflow.rs index 94939c7e4..2daa82aef 100644 --- a/compiler/rustc_borrowck/src/dataflow.rs +++ b/compiler/rustc_borrowck/src/dataflow.rs @@ -156,10 +156,10 @@ impl<'tcx> OutOfScopePrecomputer<'_, 'tcx> { &mut self, borrow_index: BorrowIndex, borrow_region: RegionVid, - location: Location, + first_location: Location, ) { // We visit one BB at a time. The complication is that we may start in the - // middle of the first BB visited (the one containing `location`), in which + // middle of the first BB visited (the one containing `first_location`), in which // case we may have to later on process the first part of that BB if there // is a path back to its start. @@ -168,61 +168,58 @@ impl<'tcx> OutOfScopePrecomputer<'_, 'tcx> { // `visited` once they are added to `stack`, before they are actually // processed, because this avoids the need to look them up again on // completion. - self.visited.insert(location.block); + self.visited.insert(first_location.block); - let mut first_lo = location.statement_index; - let first_hi = self.body[location.block].statements.len(); + let first_block = first_location.block; + let mut first_lo = first_location.statement_index; + let first_hi = self.body[first_block].statements.len(); - self.visit_stack.push(StackEntry { bb: location.block, lo: first_lo, hi: first_hi }); + self.visit_stack.push(StackEntry { bb: first_block, lo: first_lo, hi: first_hi }); - while let Some(StackEntry { bb, lo, hi }) = self.visit_stack.pop() { - // If we process the first part of the first basic block (i.e. we encounter that block - // for the second time), we no longer have to visit its successors again. - let mut finished_early = bb == location.block && hi != first_hi; - for i in lo..=hi { - let location = Location { block: bb, statement_index: i }; + 'preorder: while let Some(StackEntry { bb, lo, hi }) = self.visit_stack.pop() { + if let Some(kill_stmt) = + self.regioncx.first_non_contained_inclusive(borrow_region, bb, lo, hi) + { + let kill_location = Location { block: bb, statement_index: kill_stmt }; // If region does not contain a point at the location, then add to list and skip // successor locations. - if !self.regioncx.region_contains(borrow_region, location) { - debug!("borrow {:?} gets killed at {:?}", borrow_index, location); - self.borrows_out_of_scope_at_location - .entry(location) - .or_default() - .push(borrow_index); - finished_early = true; - break; - } + debug!("borrow {:?} gets killed at {:?}", borrow_index, kill_location); + self.borrows_out_of_scope_at_location + .entry(kill_location) + .or_default() + .push(borrow_index); + continue 'preorder; } - if !finished_early { - // Add successor BBs to the work list, if necessary. - let bb_data = &self.body[bb]; - debug_assert!(hi == bb_data.statements.len()); - for succ_bb in bb_data.terminator().successors() { - if !self.visited.insert(succ_bb) { - if succ_bb == location.block && first_lo > 0 { - // `succ_bb` has been seen before. If it wasn't - // fully processed, add its first part to `stack` - // for processing. - self.visit_stack.push(StackEntry { - bb: succ_bb, - lo: 0, - hi: first_lo - 1, - }); - - // And update this entry with 0, to represent the - // whole BB being processed. - first_lo = 0; - } - } else { - // succ_bb hasn't been seen before. Add it to - // `stack` for processing. - self.visit_stack.push(StackEntry { - bb: succ_bb, - lo: 0, - hi: self.body[succ_bb].statements.len(), - }); + // If we process the first part of the first basic block (i.e. we encounter that block + // for the second time), we no longer have to visit its successors again. + if bb == first_block && hi != first_hi { + continue; + } + + // Add successor BBs to the work list, if necessary. + let bb_data = &self.body[bb]; + debug_assert!(hi == bb_data.statements.len()); + for succ_bb in bb_data.terminator().successors() { + if !self.visited.insert(succ_bb) { + if succ_bb == first_block && first_lo > 0 { + // `succ_bb` has been seen before. If it wasn't + // fully processed, add its first part to `stack` + // for processing. + self.visit_stack.push(StackEntry { bb: succ_bb, lo: 0, hi: first_lo - 1 }); + + // And update this entry with 0, to represent the + // whole BB being processed. + first_lo = 0; } + } else { + // succ_bb hasn't been seen before. Add it to + // `stack` for processing. + self.visit_stack.push(StackEntry { + bb: succ_bb, + lo: 0, + hi: self.body[succ_bb].statements.len(), + }); } } } @@ -231,27 +228,32 @@ impl<'tcx> OutOfScopePrecomputer<'_, 'tcx> { } } +pub fn calculate_borrows_out_of_scope_at_location<'tcx>( + body: &Body<'tcx>, + regioncx: &RegionInferenceContext<'tcx>, + borrow_set: &BorrowSet<'tcx>, +) -> FxIndexMap<Location, Vec<BorrowIndex>> { + let mut prec = OutOfScopePrecomputer::new(body, regioncx); + for (borrow_index, borrow_data) in borrow_set.iter_enumerated() { + let borrow_region = borrow_data.region; + let location = borrow_data.reserve_location; + + prec.precompute_borrows_out_of_scope(borrow_index, borrow_region, location); + } + + prec.borrows_out_of_scope_at_location +} + impl<'a, 'tcx> Borrows<'a, 'tcx> { - pub(crate) fn new( + pub fn new( tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, nonlexical_regioncx: &'a RegionInferenceContext<'tcx>, borrow_set: &'a BorrowSet<'tcx>, ) -> Self { - let mut prec = OutOfScopePrecomputer::new(body, nonlexical_regioncx); - for (borrow_index, borrow_data) in borrow_set.iter_enumerated() { - let borrow_region = borrow_data.region; - let location = borrow_data.reserve_location; - - prec.precompute_borrows_out_of_scope(borrow_index, borrow_region, location); - } - - Borrows { - tcx, - body, - borrow_set, - borrows_out_of_scope_at_location: prec.borrows_out_of_scope_at_location, - } + let borrows_out_of_scope_at_location = + calculate_borrows_out_of_scope_at_location(body, nonlexical_regioncx, borrow_set); + Borrows { tcx, body, borrow_set, borrows_out_of_scope_at_location } } pub fn location(&self, idx: BorrowIndex) -> &Location { @@ -328,7 +330,7 @@ impl<'tcx> rustc_mir_dataflow::AnalysisDomain<'tcx> for Borrows<'_, 'tcx> { fn bottom_value(&self, _: &mir::Body<'tcx>) -> Self::Domain { // bottom = nothing is reserved or activated yet; - BitSet::new_empty(self.borrow_set.len() * 2) + BitSet::new_empty(self.borrow_set.len()) } fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) { |