diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src/coverage/counters.rs')
| -rw-r--r-- | compiler/rustc_mir_transform/src/coverage/counters.rs | 70 |
1 files changed, 39 insertions, 31 deletions
diff --git a/compiler/rustc_mir_transform/src/coverage/counters.rs b/compiler/rustc_mir_transform/src/coverage/counters.rs index 8c11dea5d4e..9a1d8bae6b4 100644 --- a/compiler/rustc_mir_transform/src/coverage/counters.rs +++ b/compiler/rustc_mir_transform/src/coverage/counters.rs @@ -1,4 +1,5 @@ -use rustc_data_structures::fx::FxIndexMap; +use rustc_data_structures::captures::Captures; +use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::graph::WithNumNodes; use rustc_index::bit_set::BitSet; use rustc_index::IndexVec; @@ -38,19 +39,27 @@ impl Debug for BcbCounter { } } +#[derive(Debug)] +pub(super) enum CounterIncrementSite { + Node { bcb: BasicCoverageBlock }, + Edge { from_bcb: BasicCoverageBlock, to_bcb: BasicCoverageBlock }, +} + /// Generates and stores coverage counter and coverage expression information /// associated with nodes/edges in the BCB graph. pub(super) struct CoverageCounters { - next_counter_id: CounterId, + /// List of places where a counter-increment statement should be injected + /// into MIR, each with its corresponding counter ID. + counter_increment_sites: IndexVec<CounterId, CounterIncrementSite>, /// Coverage counters/expressions that are associated with individual BCBs. bcb_counters: IndexVec<BasicCoverageBlock, Option<BcbCounter>>, /// Coverage counters/expressions that are associated with the control-flow /// edge between two BCBs. /// - /// The iteration order of this map can affect the precise contents of MIR, - /// so we use `FxIndexMap` to avoid query stability hazards. - bcb_edge_counters: FxIndexMap<(BasicCoverageBlock, BasicCoverageBlock), BcbCounter>, + /// We currently don't iterate over this map, but if we do in the future, + /// switch it back to `FxIndexMap` to avoid query stability hazards. + bcb_edge_counters: FxHashMap<(BasicCoverageBlock, BasicCoverageBlock), BcbCounter>, /// Tracks which BCBs have a counter associated with some incoming edge. /// Only used by assertions, to verify that BCBs with incoming edge /// counters do not have their own physical counters (expressions are allowed). @@ -71,9 +80,9 @@ impl CoverageCounters { let num_bcbs = basic_coverage_blocks.num_nodes(); let mut this = Self { - next_counter_id: CounterId::START, + counter_increment_sites: IndexVec::new(), bcb_counters: IndexVec::from_elem_n(None, num_bcbs), - bcb_edge_counters: FxIndexMap::default(), + bcb_edge_counters: FxHashMap::default(), bcb_has_incoming_edge_counters: BitSet::new_empty(num_bcbs), expressions: IndexVec::new(), }; @@ -84,8 +93,8 @@ impl CoverageCounters { this } - fn make_counter(&mut self) -> BcbCounter { - let id = self.next_counter(); + fn make_counter(&mut self, site: CounterIncrementSite) -> BcbCounter { + let id = self.counter_increment_sites.push(site); BcbCounter::Counter { id } } @@ -103,15 +112,8 @@ impl CoverageCounters { self.make_expression(lhs, Op::Add, rhs) } - /// Counter IDs start from one and go up. - fn next_counter(&mut self) -> CounterId { - let next = self.next_counter_id; - self.next_counter_id = self.next_counter_id + 1; - next - } - pub(super) fn num_counters(&self) -> usize { - self.next_counter_id.as_usize() + self.counter_increment_sites.len() } #[cfg(test)] @@ -171,22 +173,26 @@ impl CoverageCounters { self.bcb_counters[bcb] } - pub(super) fn bcb_node_counters( + /// Returns an iterator over all the nodes/edges in the coverage graph that + /// should have a counter-increment statement injected into MIR, along with + /// each site's corresponding counter ID. + pub(super) fn counter_increment_sites( &self, - ) -> impl Iterator<Item = (BasicCoverageBlock, &BcbCounter)> { - self.bcb_counters - .iter_enumerated() - .filter_map(|(bcb, counter_kind)| Some((bcb, counter_kind.as_ref()?))) + ) -> impl Iterator<Item = (CounterId, &CounterIncrementSite)> { + self.counter_increment_sites.iter_enumerated() } - /// For each edge in the BCB graph that has an associated counter, yields - /// that edge's *from* and *to* nodes, and its counter. - pub(super) fn bcb_edge_counters( + /// Returns an iterator over the subset of BCB nodes that have been associated + /// with a counter *expression*, along with the ID of that expression. + pub(super) fn bcb_nodes_with_coverage_expressions( &self, - ) -> impl Iterator<Item = (BasicCoverageBlock, BasicCoverageBlock, &BcbCounter)> { - self.bcb_edge_counters - .iter() - .map(|(&(from_bcb, to_bcb), counter_kind)| (from_bcb, to_bcb, counter_kind)) + ) -> impl Iterator<Item = (BasicCoverageBlock, ExpressionId)> + Captures<'_> { + self.bcb_counters.iter_enumerated().filter_map(|(bcb, &counter_kind)| match counter_kind { + // Yield the BCB along with its associated expression ID. + Some(BcbCounter::Expression { id }) => Some((bcb, id)), + // This BCB is associated with a counter or nothing, so skip it. + Some(BcbCounter::Counter { .. }) | None => None, + }) } pub(super) fn into_expressions(self) -> IndexVec<ExpressionId, Expression> { @@ -339,7 +345,8 @@ impl<'a> MakeBcbCounters<'a> { // program results in a tight infinite loop, but it should still compile. let one_path_to_target = !self.basic_coverage_blocks.bcb_has_multiple_in_edges(bcb); if one_path_to_target || self.bcb_predecessors(bcb).contains(&bcb) { - let counter_kind = self.coverage_counters.make_counter(); + let counter_kind = + self.coverage_counters.make_counter(CounterIncrementSite::Node { bcb }); if one_path_to_target { debug!("{bcb:?} gets a new counter: {counter_kind:?}"); } else { @@ -401,7 +408,8 @@ impl<'a> MakeBcbCounters<'a> { } // Make a new counter to count this edge. - let counter_kind = self.coverage_counters.make_counter(); + let counter_kind = + self.coverage_counters.make_counter(CounterIncrementSite::Edge { from_bcb, to_bcb }); debug!("Edge {from_bcb:?}->{to_bcb:?} gets a new counter: {counter_kind:?}"); self.coverage_counters.set_bcb_edge_counter(from_bcb, to_bcb, counter_kind) } |