diff options
| -rw-r--r-- | src/librustc/infer/lexical_region_resolve/mod.rs | 67 |
1 files changed, 28 insertions, 39 deletions
diff --git a/src/librustc/infer/lexical_region_resolve/mod.rs b/src/librustc/infer/lexical_region_resolve/mod.rs index a8d1b264760..f30f19d4150 100644 --- a/src/librustc/infer/lexical_region_resolve/mod.rs +++ b/src/librustc/infer/lexical_region_resolve/mod.rs @@ -304,8 +304,7 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { } fn expansion(&self, var_values: &mut LexicalRegionResolutions<'tcx>) { - self.iterate_until_fixed_point(|constraint| { - debug!("expansion: constraint={:?}", constraint); + let mut process_constraint = |constraint: &Constraint<'tcx>| { let (a_region, b_vid, b_data, retain) = match *constraint { Constraint::RegSubVar(a_region, b_vid) => { let b_data = var_values.value_mut(b_vid); @@ -331,7 +330,33 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { let changed = self.expand_node(a_region, b_vid, b_data); (changed, retain) - }) + }; + + // Using bitsets to track the remaining elements is faster than using a + // `Vec` by itself (which requires removing elements, which requires + // element shuffling, which is slow). + let constraints: Vec<_> = self.data.constraints.keys().collect(); + let mut live_indices: BitSet<usize> = BitSet::new_filled(constraints.len()); + let mut killed_indices: BitSet<usize> = BitSet::new_empty(constraints.len()); + let mut changed = true; + while changed { + changed = false; + for index in live_indices.iter() { + let constraint = constraints[index]; + let (edge_changed, retain) = process_constraint(constraint); + if edge_changed { + changed = true; + } + if !retain { + let changed = killed_indices.insert(index); + debug_assert!(changed); + } + } + live_indices.subtract(&killed_indices); + + // We could clear `killed_indices` here, but we don't need to and + // it's cheaper not to. + } } // This function is very hot in some workloads. There's a single callsite @@ -866,42 +891,6 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { } } - fn iterate_until_fixed_point<F>(&self, mut body: F) - where - F: FnMut(&Constraint<'tcx>) -> (bool, bool), - { - // Using bitsets to track the remaining elements is faster than using a - // `Vec` by itself (which requires removing elements, which requires - // element shuffling, which is slow). - let constraints: Vec<_> = self.data.constraints.keys().collect(); - let mut live_indices: BitSet<usize> = BitSet::new_filled(constraints.len()); - let mut killed_indices: BitSet<usize> = BitSet::new_empty(constraints.len()); - let mut iteration = 0; - let mut changed = true; - while changed { - changed = false; - iteration += 1; - debug!("---- Expansion iteration {}", iteration); - for index in live_indices.iter() { - let constraint = constraints[index]; - let (edge_changed, retain) = body(constraint); - if edge_changed { - debug!("updated due to constraint {:?}", constraint); - changed = true; - } - if !retain { - let changed = killed_indices.insert(index); - debug_assert!(changed); - } - } - live_indices.subtract(&killed_indices); - - // We could clear `killed_indices` here, but we don't need to and - // it's cheaper not to. - } - debug!("---- Expansion complete after {} iteration(s)", iteration); - } - fn bound_is_met( &self, bound: &VerifyBound<'tcx>, |