1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139

//! This module provides linkage between RegionInferenceContext and
//! `rustc_graphviz` traits, specialized to attaching borrowck analysis
//! data to rendered labels.

use std::borrow::Cow;
use std::io::{self, Write};

use super::*;
use rustc_graphviz as dot;

impl<'tcx> RegionInferenceContext<'tcx> {
    /// Write out the region constraint graph.
    pub(crate) fn dump_graphviz_raw_constraints(&self, mut w: &mut dyn Write) -> io::Result<()> {
        dot::render(&RawConstraints { regioncx: self }, &mut w)
    }

    /// Write out the region constraint graph.
    pub(crate) fn dump_graphviz_scc_constraints(&self, mut w: &mut dyn Write) -> io::Result<()> {
        let mut nodes_per_scc: IndexVec<ConstraintSccIndex, _> =
            self.constraint_sccs.all_sccs().map(|_| Vec::new()).collect();

        for region in self.definitions.indices() {
            let scc = self.constraint_sccs.scc(region);
            nodes_per_scc[scc].push(region);
        }

        dot::render(&SccConstraints { regioncx: self, nodes_per_scc }, &mut w)
    }
}

struct RawConstraints<'a, 'tcx> {
    regioncx: &'a RegionInferenceContext<'tcx>,
}

impl<'a, 'this, 'tcx> dot::Labeller<'this> for RawConstraints<'a, 'tcx> {
    type Node = RegionVid;
    type Edge = OutlivesConstraint<'tcx>;

    fn graph_id(&'this self) -> dot::Id<'this> {
        dot::Id::new("RegionInferenceContext").unwrap()
    }
    fn node_id(&'this self, n: &RegionVid) -> dot::Id<'this> {
        dot::Id::new(format!("r{}", n.index())).unwrap()
    }
    fn node_shape(&'this self, _node: &RegionVid) -> Option<dot::LabelText<'this>> {
        Some(dot::LabelText::LabelStr(Cow::Borrowed("box")))
    }
    fn node_label(&'this self, n: &RegionVid) -> dot::LabelText<'this> {
        dot::LabelText::LabelStr(format!("{n:?}").into())
    }
    fn edge_label(&'this self, e: &OutlivesConstraint<'tcx>) -> dot::LabelText<'this> {
        dot::LabelText::LabelStr(format!("{:?}", e.locations).into())
    }
}

impl<'a, 'this, 'tcx> dot::GraphWalk<'this> for RawConstraints<'a, 'tcx> {
    type Node = RegionVid;
    type Edge = OutlivesConstraint<'tcx>;

    fn nodes(&'this self) -> dot::Nodes<'this, RegionVid> {
        let vids: Vec<RegionVid> = self.regioncx.definitions.indices().collect();
        vids.into()
    }
    fn edges(&'this self) -> dot::Edges<'this, OutlivesConstraint<'tcx>> {
        (&self.regioncx.constraints.outlives().raw[..]).into()
    }

    // Render `a: b` as `a -> b`, indicating the flow
    // of data during inference.

    fn source(&'this self, edge: &OutlivesConstraint<'tcx>) -> RegionVid {
        edge.sup
    }

    fn target(&'this self, edge: &OutlivesConstraint<'tcx>) -> RegionVid {
        edge.sub
    }
}

struct SccConstraints<'a, 'tcx> {
    regioncx: &'a RegionInferenceContext<'tcx>,
    nodes_per_scc: IndexVec<ConstraintSccIndex, Vec<RegionVid>>,
}

impl<'a, 'this, 'tcx> dot::Labeller<'this> for SccConstraints<'a, 'tcx> {
    type Node = ConstraintSccIndex;
    type Edge = (ConstraintSccIndex, ConstraintSccIndex);

    fn graph_id(&'this self) -> dot::Id<'this> {
        dot::Id::new("RegionInferenceContext".to_string()).unwrap()
    }
    fn node_id(&'this self, n: &ConstraintSccIndex) -> dot::Id<'this> {
        dot::Id::new(format!("r{}", n.index())).unwrap()
    }
    fn node_shape(&'this self, _node: &ConstraintSccIndex) -> Option<dot::LabelText<'this>> {
        Some(dot::LabelText::LabelStr(Cow::Borrowed("box")))
    }
    fn node_label(&'this self, n: &ConstraintSccIndex) -> dot::LabelText<'this> {
        let nodes = &self.nodes_per_scc[*n];
        dot::LabelText::LabelStr(format!("{n:?} = {nodes:?}").into())
    }
}

impl<'a, 'this, 'tcx> dot::GraphWalk<'this> for SccConstraints<'a, 'tcx> {
    type Node = ConstraintSccIndex;
    type Edge = (ConstraintSccIndex, ConstraintSccIndex);

    fn nodes(&'this self) -> dot::Nodes<'this, ConstraintSccIndex> {
        let vids: Vec<ConstraintSccIndex> = self.regioncx.constraint_sccs.all_sccs().collect();
        vids.into()
    }
    fn edges(&'this self) -> dot::Edges<'this, (ConstraintSccIndex, ConstraintSccIndex)> {
        let edges: Vec<_> = self
            .regioncx
            .constraint_sccs
            .all_sccs()
            .flat_map(|scc_a| {
                self.regioncx
                    .constraint_sccs
                    .successors(scc_a)
                    .iter()
                    .map(move |&scc_b| (scc_a, scc_b))
            })
            .collect();

        edges.into()
    }

    // Render `a: b` as `a -> b`, indicating the flow
    // of data during inference.

    fn source(&'this self, edge: &(ConstraintSccIndex, ConstraintSccIndex)) -> ConstraintSccIndex {
        edge.0
    }

    fn target(&'this self, edge: &(ConstraintSccIndex, ConstraintSccIndex)) -> ConstraintSccIndex {
        edge.1
    }
}