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Avoid getting dep_dep_node unnecessarily. #147293

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Merged
merged 2 commits into from
Oct 5, 2025
+11 −8
Merged

Avoid getting dep_dep_node unnecessarily. #147293

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cb0f969
Avoid getting `dep_dep_node` unnecessarily.
nnethercote Oct 3, 2025
3a287e6
Remove some unnecessary locals.
nnethercote Oct 3, 2025
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19 changes: 11 additions & 8 deletions compiler/rustc_query_system/src/dep_graph/graph.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -875,28 +875,33 @@ impl<D: Deps> DepGraphData<D> {
parent_dep_node_index: SerializedDepNodeIndex,
frame: Option<&MarkFrame<'_>>,
) -> Option<()> {
let dep_dep_node_color = self.colors.get(parent_dep_node_index);
let dep_dep_node = &self.previous.index_to_node(parent_dep_node_index);
let get_dep_dep_node = || self.previous.index_to_node(parent_dep_node_index);

match dep_dep_node_color {
match self.colors.get(parent_dep_node_index) {
Some(DepNodeColor::Green(_)) => {
// This dependency has been marked as green before, we are
// still fine and can continue with checking the other
// dependencies.
debug!("dependency {dep_dep_node:?} was immediately green");
//
// This path is extremely hot. We don't want to get the
// `dep_dep_node` unless it's necessary. Hence the
// `get_dep_dep_node` closure.
debug!("dependency {:?} was immediately green", get_dep_dep_node());
return Some(());
}
Some(DepNodeColor::Red) => {
// We found a dependency the value of which has changed
// compared to the previous compilation session. We cannot
// mark the DepNode as green and also don't need to bother
// with checking any of the other dependencies.
debug!("dependency {dep_dep_node:?} was immediately red");
debug!("dependency {:?} was immediately red", get_dep_dep_node());
return None;
}
None => {}
}

let dep_dep_node = &get_dep_dep_node();

// We don't know the state of this dependency. If it isn't
// an eval_always node, let's try to mark it green recursively.
if !qcx.dep_context().is_eval_always(dep_dep_node.kind) {
Expand All @@ -922,9 +927,7 @@ impl<D: Deps> DepGraphData<D> {
return None;
}

let dep_dep_node_color = self.colors.get(parent_dep_node_index);

match dep_dep_node_color {
match self.colors.get(parent_dep_node_index) {
Some(DepNodeColor::Green(_)) => {
debug!("managed to FORCE dependency {dep_dep_node:?} to green");
return Some(());
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