rustc_middle/dep_graph/
retained.rs

1use rustc_data_structures::fx::FxHashMap;
2use rustc_data_structures::graph::linked_graph::{Direction, INCOMING, LinkedGraph, NodeIndex};
3use rustc_index::IndexVec;
4
5use super::{DepNode, DepNodeIndex};
6
7/// An in-memory copy of the current session's query dependency graph, which
8/// is only enabled when `-Zquery-dep-graph` is set (for debugging/testing).
9///
10/// Normally, dependencies recorded during the current session are written to
11/// disk and then forgotten, to avoid wasting memory on information that is
12/// not needed when the compiler is working correctly.
13pub struct RetainedDepGraph {
14    pub inner: LinkedGraph<DepNode, ()>,
15    pub indices: FxHashMap<DepNode, NodeIndex>,
16    pub dep_index_to_index: IndexVec<DepNodeIndex, Option<NodeIndex>>,
17}
18
19impl RetainedDepGraph {
20    pub fn new(prev_node_count: usize) -> Self {
21        let node_count = prev_node_count + prev_node_count / 4;
22        let edge_count = 6 * node_count;
23
24        let inner = LinkedGraph::with_capacity(node_count, edge_count);
25        let indices = FxHashMap::default();
26        let dep_index_to_index = IndexVec::new();
27
28        Self { inner, indices, dep_index_to_index }
29    }
30
31    pub fn push(&mut self, index: DepNodeIndex, node: DepNode, edges: &[DepNodeIndex]) {
32        let source = self.inner.add_node(node);
33        self.dep_index_to_index.insert(index, source);
34        self.indices.insert(node, source);
35
36        for &target in edges.iter() {
37            // We may miss the edges that are pushed while the `DepGraphQuery` is being accessed.
38            // Skip them to issues.
39            if let Some(&Some(target)) = self.dep_index_to_index.get(target) {
40                self.inner.add_edge(source, target, ());
41            }
42        }
43    }
44
45    pub fn nodes(&self) -> Vec<&DepNode> {
46        self.inner.all_nodes().iter().map(|n| &n.data).collect()
47    }
48
49    pub fn edges(&self) -> Vec<(&DepNode, &DepNode)> {
50        self.inner
51            .all_edges()
52            .iter()
53            .map(|edge| (edge.source(), edge.target()))
54            .map(|(s, t)| (self.inner.node_data(s), self.inner.node_data(t)))
55            .collect()
56    }
57
58    fn reachable_nodes(&self, node: &DepNode, direction: Direction) -> Vec<&DepNode> {
59        if let Some(&index) = self.indices.get(node) {
60            self.inner.depth_traverse(index, direction).map(|s| self.inner.node_data(s)).collect()
61        } else {
62            ::alloc::vec::Vec::new()vec![]
63        }
64    }
65
66    /// All nodes that can reach `node`.
67    pub fn transitive_predecessors(&self, node: &DepNode) -> Vec<&DepNode> {
68        self.reachable_nodes(node, INCOMING)
69    }
70}
rustc_middle/dep_graph/retained.rs

rustc_middle/dep_graph/
retained.rs
