bjoernager/rust
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coverage: Replace bcb_has_multiple_in_edges with sole_predecessor

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This does a better job of expressing the special cases that occur when a node
in the coverage graph has exactly one in-edge.
This commit is contained in:
Zalathar 2024-09-13 20:34:12 +10:00
parent e24310b07c
commit 669327f575
2 changed files with 29 additions and 34 deletions
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39
compiler/rustc_mir_transform/src/coverage/counters.rs
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@ -364,10 +364,13 @@ impl<'a> MakeBcbCounters<'a> {
);
debug!("{expression_to_bcb:?} gets an expression: {expression:?}");
if self.basic_coverage_blocks.bcb_has_multiple_in_edges(expression_to_bcb) {
self.coverage_counters.set_bcb_edge_counter(from_bcb, expression_to_bcb, expression);
} else {
if let Some(sole_pred) = self.basic_coverage_blocks.sole_predecessor(expression_to_bcb) {
// This edge normally wouldn't get its own counter, so attach the expression
// to its target node instead, so that `edge_has_no_counter` can see it.
assert_eq!(sole_pred, from_bcb);
self.coverage_counters.set_bcb_counter(expression_to_bcb, expression);
} else {
self.coverage_counters.set_bcb_edge_counter(from_bcb, expression_to_bcb, expression);
}
}
@ -413,10 +416,12 @@ impl<'a> MakeBcbCounters<'a> {
from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock,
) -> BcbCounter {
// If the target BCB has only one in-edge (i.e. this one), then create
// a node counter instead, since it will have the same value.
if !self.basic_coverage_blocks.bcb_has_multiple_in_edges(to_bcb) {
assert_eq!([from_bcb].as_slice(), self.basic_coverage_blocks.predecessors[to_bcb]);
// If the target node has exactly one in-edge (i.e. this one), then just
// use the node's counter, since it will have the same value.
if let Some(sole_pred) = self.basic_coverage_blocks.sole_predecessor(to_bcb) {
assert_eq!(sole_pred, from_bcb);
// This call must take care not to invoke `get_or_make_edge` for
// this edge, since that would result in infinite recursion!
return self.get_or_make_node_counter(to_bcb);
}
@ -508,18 +513,14 @@ impl<'a> MakeBcbCounters<'a> {
from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock,
) -> bool {
self.edge_counter(from_bcb, to_bcb).is_none()
}
let edge_counter =
if let Some(sole_pred) = self.basic_coverage_blocks.sole_predecessor(to_bcb) {
assert_eq!(sole_pred, from_bcb);
self.coverage_counters.bcb_counters[to_bcb]
} else {
self.coverage_counters.bcb_edge_counters.get(&(from_bcb, to_bcb)).copied()
};
fn edge_counter(
&self,
from_bcb: BasicCoverageBlock,
to_bcb: BasicCoverageBlock,
) -> Option<&BcbCounter> {
if self.basic_coverage_blocks.bcb_has_multiple_in_edges(to_bcb) {
self.coverage_counters.bcb_edge_counters.get(&(from_bcb, to_bcb))
} else {
self.coverage_counters.bcb_counters[to_bcb].as_ref()
}
edge_counter.is_none()
}
}