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Reuse the index from promoted nodes when coloring executed tasks #139410

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Merged
merged 1 commit into from
Apr 11, 2025
Merged

Reuse the index from promoted nodes when coloring executed tasks #139410

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83 changes: 50 additions & 33 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 @@ -141,15 +141,15 @@ impl<D: Deps> DepGraph<D> {
let colors = DepNodeColorMap::new(prev_graph_node_count);

// Instantiate a node with zero dependencies only once for anonymous queries.
let _green_node_index = current.alloc_node(
let _green_node_index = current.alloc_new_node(
DepNode { kind: D::DEP_KIND_ANON_ZERO_DEPS, hash: current.anon_id_seed.into() },
EdgesVec::new(),
Fingerprint::ZERO,
);
assert_eq!(_green_node_index, DepNodeIndex::SINGLETON_ZERO_DEPS_ANON_NODE);

// Instantiate a dependy-less red node only once for anonymous queries.
let red_node_index = current.alloc_node(
let red_node_index = current.alloc_new_node(
DepNode { kind: D::DEP_KIND_RED, hash: Fingerprint::ZERO.into() },
EdgesVec::new(),
Fingerprint::ZERO,
Expand Down Expand Up @@ -438,7 +438,7 @@ impl<D: Deps> DepGraphData<D> {
// memory impact of this `anon_node_to_index` map remains tolerable, and helps
// us avoid useless growth of the graph with almost-equivalent nodes.
self.current.anon_node_to_index.get_or_insert_with(target_dep_node, || {
self.current.alloc_node(target_dep_node, task_deps, Fingerprint::ZERO)
self.current.alloc_new_node(target_dep_node, task_deps, Fingerprint::ZERO)
})
}
};
Expand Down Expand Up @@ -680,8 +680,8 @@ impl<D: Deps> DepGraphData<D> {
qcx: Qcx,
diagnostic: &DiagInner,
) -> DepNodeIndex {
// Use `send` so we get an unique index, even though the dep node is not.
let dep_node_index = self.current.encoder.send(
// Use `send_new` so we get an unique index, even though the dep node is not.
let dep_node_index = self.current.encoder.send_new(
DepNode {
kind: D::DEP_KIND_SIDE_EFFECT,
hash: PackedFingerprint::from(Fingerprint::ZERO),
Expand Down Expand Up @@ -713,20 +713,22 @@ impl<D: Deps> DepGraphData<D> {
}
}

// Manually recreate the node as `promote_node_and_deps_to_current` expects all
// green dependencies.
let dep_node_index = self.current.encoder.send(
// Use `send_and_color` as `promote_node_and_deps_to_current` expects all
// green dependencies. `send_and_color` will also prevent multiple nodes
// being encoded for concurrent calls.
let dep_node_index = self.current.encoder.send_and_color(
prev_index,
&self.colors,
DepNode {
kind: D::DEP_KIND_SIDE_EFFECT,
hash: PackedFingerprint::from(Fingerprint::ZERO),
},
Fingerprint::ZERO,
std::iter::once(DepNodeIndex::FOREVER_RED_NODE).collect(),
true,
);
// This will just overwrite the same value for concurrent calls.
qcx.store_side_effect(dep_node_index, side_effect);

// Mark the node as green.
self.colors.insert(prev_index, DepNodeColor::Green(dep_node_index));
})
}

Expand All @@ -736,38 +738,43 @@ impl<D: Deps> DepGraphData<D> {
edges: EdgesVec,
fingerprint: Option<Fingerprint>,
) -> DepNodeIndex {
let dep_node_index =
self.current.alloc_node(key, edges, fingerprint.unwrap_or(Fingerprint::ZERO));

if let Some(prev_index) = self.previous.node_to_index_opt(&key) {
// Determine the color and index of the new `DepNode`.
let color = if let Some(fingerprint) = fingerprint {
let is_green = if let Some(fingerprint) = fingerprint {
if fingerprint == self.previous.fingerprint_by_index(prev_index) {
// This is a green node: it existed in the previous compilation,
// its query was re-executed, and it has the same result as before.
DepNodeColor::Green(dep_node_index)
true
} else {
// This is a red node: it existed in the previous compilation, its query
// was re-executed, but it has a different result from before.
DepNodeColor::Red
false
}
} else {
// This is a red node, effectively: it existed in the previous compilation
// session, its query was re-executed, but it doesn't compute a result hash
// (i.e. it represents a `no_hash` query), so we have no way of determining
// whether or not the result was the same as before.
DepNodeColor::Red
false
};

debug_assert!(
self.colors.get(prev_index).is_none(),
"DepGraph::with_task() - Duplicate DepNodeColor insertion for {key:?}",
let fingerprint = fingerprint.unwrap_or(Fingerprint::ZERO);

let dep_node_index = self.current.encoder.send_and_color(
prev_index,
&self.colors,
key,
fingerprint,
edges,
is_green,
);

self.colors.insert(prev_index, color);
}
self.current.record_node(dep_node_index, key, fingerprint);

dep_node_index
dep_node_index
} else {
self.current.alloc_new_node(key, edges, fingerprint.unwrap_or(Fingerprint::ZERO))
}
}

fn promote_node_and_deps_to_current(&self, prev_index: SerializedDepNodeIndex) -> DepNodeIndex {
Expand Down Expand Up @@ -1246,19 +1253,15 @@ impl<D: Deps> CurrentDepGraph<D> {
assert_eq!(previous, fingerprint, "Unstable fingerprints for {:?}", key);
}

/// Writes the node to the current dep-graph and allocates a `DepNodeIndex` for it.
/// Assumes that this is a node that has no equivalent in the previous dep-graph.
#[inline(always)]
fn alloc_node(
fn record_node(
&self,
dep_node_index: DepNodeIndex,
key: DepNode,
edges: EdgesVec,
current_fingerprint: Fingerprint,
) -> DepNodeIndex {
let dep_node_index = self.encoder.send(key, current_fingerprint, edges);

_current_fingerprint: Fingerprint,
) {
#[cfg(debug_assertions)]
self.record_edge(dep_node_index, key, current_fingerprint);
self.record_edge(dep_node_index, key, _current_fingerprint);

if let Some(ref nodes_in_current_session) = self.nodes_in_current_session {
outline(|| {
Expand All @@ -1267,6 +1270,20 @@ impl<D: Deps> CurrentDepGraph<D> {
}
});
}
}

/// Writes the node to the current dep-graph and allocates a `DepNodeIndex` for it.
/// Assumes that this is a node that has no equivalent in the previous dep-graph.
#[inline(always)]
fn alloc_new_node(
&self,
key: DepNode,
edges: EdgesVec,
current_fingerprint: Fingerprint,
) -> DepNodeIndex {
let dep_node_index = self.encoder.send_new(key, current_fingerprint, edges);

self.record_node(dep_node_index, key, current_fingerprint);

dep_node_index
}
Expand Down
41 changes: 38 additions & 3 deletions compiler/rustc_query_system/src/dep_graph/serialized.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -707,7 +707,8 @@ impl<D: Deps> GraphEncoder<D> {
}
}

pub(crate) fn send(
/// Encodes a node that does not exists in the previous graph.
pub(crate) fn send_new(
&self,
node: DepNode,
fingerprint: Fingerprint,
Expand All @@ -718,6 +719,40 @@ impl<D: Deps> GraphEncoder<D> {
self.status.lock().as_mut().unwrap().encode_node(&node, &self.record_graph)
}

/// Encodes a node that exists in the previous graph, but was re-executed.
///
/// This will also ensure the dep node is colored either red or green.
pub(crate) fn send_and_color(
&self,
prev_index: SerializedDepNodeIndex,
colors: &DepNodeColorMap,
node: DepNode,
fingerprint: Fingerprint,
edges: EdgesVec,
is_green: bool,
) -> DepNodeIndex {
let _prof_timer = self.profiler.generic_activity("incr_comp_encode_dep_graph");
let node = NodeInfo { node, fingerprint, edges };

let mut status = self.status.lock();
let status = status.as_mut().unwrap();

// Check colors inside the lock to avoid racing when `send_promoted` is called concurrently
// on the same index.
match colors.get(prev_index) {
None => {
let dep_node_index = status.encode_node(&node, &self.record_graph);
colors.insert(
prev_index,
if is_green { DepNodeColor::Green(dep_node_index) } else { DepNodeColor::Red },
);
dep_node_index
}
Some(DepNodeColor::Green(dep_node_index)) => dep_node_index,
Some(DepNodeColor::Red) => panic!(),
}
}

/// Encodes a node that was promoted from the previous graph. It reads the information directly from
/// the previous dep graph and expects all edges to already have a new dep node index assigned.
///
Expand All @@ -733,8 +768,8 @@ impl<D: Deps> GraphEncoder<D> {
let mut status = self.status.lock();
let status = status.as_mut().unwrap();

// Check colors inside the lock to avoid racing when `send_promoted` is called concurrently
// on the same index.
// Check colors inside the lock to avoid racing when `send_promoted` or `send_and_color`
// is called concurrently on the same index.
match colors.get(prev_index) {
None => {
let dep_node_index =
Expand Down
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