src/librustc_mir/borrow_check/region_infer/graphviz.rs

   1 //! This module provides linkage between RegionInferenceContext and
   2 //! librustc_graphviz traits, specialized to attaching borrowck analysis
   3 //! data to rendered labels.
   4
   5 use std::borrow::Cow;
   6 use std::io::{self, Write};
   7
   8 use super::*;
   9 use crate::borrow_check::constraints::OutlivesConstraint;
  10 use rustc_graphviz as dot;
  11
  12 impl<'tcx> RegionInferenceContext<'tcx> {
  13     /// Write out the region constraint graph.
  14     crate fn dump_graphviz_raw_constraints(&self, mut w: &mut dyn Write) -> io::Result<()> {
  15         dot::render(&RawConstraints { regioncx: self }, &mut w)
  16     }
  17
  18     /// Write out the region constraint graph.
  19     crate fn dump_graphviz_scc_constraints(&self, mut w: &mut dyn Write) -> io::Result<()> {
  20         let mut nodes_per_scc: IndexVec<ConstraintSccIndex, _> =
  21             self.constraint_sccs.all_sccs().map(|_| Vec::new()).collect();
  22
  23         for region in self.definitions.indices() {
  24             let scc = self.constraint_sccs.scc(region);
  25             nodes_per_scc[scc].push(region);
  26         }
  27
  28         dot::render(&SccConstraints { regioncx: self, nodes_per_scc }, &mut w)
  29     }
  30 }
  31
  32 struct RawConstraints<'a, 'tcx> {
  33     regioncx: &'a RegionInferenceContext<'tcx>,
  34 }
  35
  36 impl<'a, 'this, 'tcx> dot::Labeller<'this> for RawConstraints<'a, 'tcx> {
  37     type Node = RegionVid;
  38     type Edge = OutlivesConstraint;
  39
  40     fn graph_id(&'this self) -> dot::Id<'this> {
  41         dot::Id::new("RegionInferenceContext").unwrap()
  42     }
  43     fn node_id(&'this self, n: &RegionVid) -> dot::Id<'this> {
  44         dot::Id::new(format!("r{}", n.index())).unwrap()
  45     }
  46     fn node_shape(&'this self, _node: &RegionVid) -> Option<dot::LabelText<'this>> {
  47         Some(dot::LabelText::LabelStr(Cow::Borrowed("box")))
  48     }
  49     fn node_label(&'this self, n: &RegionVid) -> dot::LabelText<'this> {
  50         dot::LabelText::LabelStr(format!("{:?}", n).into())
  51     }
  52     fn edge_label(&'this self, e: &OutlivesConstraint) -> dot::LabelText<'this> {
  53         dot::LabelText::LabelStr(format!("{:?}", e.locations).into())
  54     }
  55 }
  56
  57 impl<'a, 'this, 'tcx> dot::GraphWalk<'this> for RawConstraints<'a, 'tcx> {
  58     type Node = RegionVid;
  59     type Edge = OutlivesConstraint;
  60
  61     fn nodes(&'this self) -> dot::Nodes<'this, RegionVid> {
  62         let vids: Vec<RegionVid> = self.regioncx.definitions.indices().collect();
  63         vids.into()
  64     }
  65     fn edges(&'this self) -> dot::Edges<'this, OutlivesConstraint> {
  66         (&self.regioncx.constraints.outlives().raw[..]).into()
  67     }
  68
  69     // Render `a: b` as `a -> b`, indicating the flow
  70     // of data during inference.
  71
  72     fn source(&'this self, edge: &OutlivesConstraint) -> RegionVid {
  73         edge.sup
  74     }
  75
  76     fn target(&'this self, edge: &OutlivesConstraint) -> RegionVid {
  77         edge.sub
  78     }
  79 }
  80
  81 struct SccConstraints<'a, 'tcx> {
  82     regioncx: &'a RegionInferenceContext<'tcx>,
  83     nodes_per_scc: IndexVec<ConstraintSccIndex, Vec<RegionVid>>,
  84 }
  85
  86 impl<'a, 'this, 'tcx> dot::Labeller<'this> for SccConstraints<'a, 'tcx> {
  87     type Node = ConstraintSccIndex;
  88     type Edge = (ConstraintSccIndex, ConstraintSccIndex);
  89
  90     fn graph_id(&'this self) -> dot::Id<'this> {
  91         dot::Id::new("RegionInferenceContext".to_string()).unwrap()
  92     }
  93     fn node_id(&'this self, n: &ConstraintSccIndex) -> dot::Id<'this> {
  94         dot::Id::new(format!("r{}", n.index())).unwrap()
  95     }
  96     fn node_shape(&'this self, _node: &ConstraintSccIndex) -> Option<dot::LabelText<'this>> {
  97         Some(dot::LabelText::LabelStr(Cow::Borrowed("box")))
  98     }
  99     fn node_label(&'this self, n: &ConstraintSccIndex) -> dot::LabelText<'this> {
 100         let nodes = &self.nodes_per_scc[*n];
 101         dot::LabelText::LabelStr(format!("{:?} = {:?}", n, nodes).into())
 102     }
 103 }
 104
 105 impl<'a, 'this, 'tcx> dot::GraphWalk<'this> for SccConstraints<'a, 'tcx> {
 106     type Node = ConstraintSccIndex;
 107     type Edge = (ConstraintSccIndex, ConstraintSccIndex);
 108
 109     fn nodes(&'this self) -> dot::Nodes<'this, ConstraintSccIndex> {
 110         let vids: Vec<ConstraintSccIndex> = self.regioncx.constraint_sccs.all_sccs().collect();
 111         vids.into()
 112     }
 113     fn edges(&'this self) -> dot::Edges<'this, (ConstraintSccIndex, ConstraintSccIndex)> {
 114         let edges: Vec<_> = self
 115             .regioncx
 116             .constraint_sccs
 117             .all_sccs()
 118             .flat_map(|scc_a| {
 119                 self.regioncx
 120                     .constraint_sccs
 121                     .successors(scc_a)
 122                     .iter()
 123                     .map(move |&scc_b| (scc_a, scc_b))
 124             })
 125             .collect();
 126
 127         edges.into()
 128     }
 129
 130     // Render `a: b` as `a -> b`, indicating the flow
 131     // of data during inference.
 132
 133     fn source(&'this self, edge: &(ConstraintSccIndex, ConstraintSccIndex)) -> ConstraintSccIndex {
 134         edge.0
 135     }
 136
 137     fn target(&'this self, edge: &(ConstraintSccIndex, ConstraintSccIndex)) -> ConstraintSccIndex {
 138         edge.1
 139     }
 140 }