compiler/rustc_typeck/src/check/generator_interior/drop_ranges/cfg_visualize.rs

   1 //! Implementation of GraphWalk for DropRanges so we can visualize the control
   2 //! flow graph when needed for debugging.
   3
   4 use rustc_graphviz as dot;
   5
   6 use super::{DropRangesBuilder, PostOrderId};
   7
   8 /// Writes the CFG for DropRangesBuilder to a .dot file for visualization.
   9 ///
  10 /// It is not normally called, but is kept around to easily add debugging
  11 /// code when needed.
  12 #[allow(dead_code)]
  13 pub(super) fn write_graph_to_file(drop_ranges: &DropRangesBuilder, filename: &str) {
  14     dot::render(drop_ranges, &mut std::fs::File::create(filename).unwrap()).unwrap();
  15 }
  16
  17 impl<'a> dot::GraphWalk<'a> for DropRangesBuilder {
  18     type Node = PostOrderId;
  19
  20     type Edge = (PostOrderId, PostOrderId);
  21
  22     fn nodes(&'a self) -> dot::Nodes<'a, Self::Node> {
  23         self.nodes.iter_enumerated().map(|(i, _)| i).collect()
  24     }
  25
  26     fn edges(&'a self) -> dot::Edges<'a, Self::Edge> {
  27         self.nodes
  28             .iter_enumerated()
  29             .flat_map(|(i, node)| {
  30                 if node.successors.len() == 0 {
  31                     vec![(i, i + 1)]
  32                 } else {
  33                     node.successors.iter().map(move |&s| (i, s)).collect()
  34                 }
  35             })
  36             .collect()
  37     }
  38
  39     fn source(&'a self, edge: &Self::Edge) -> Self::Node {
  40         edge.0
  41     }
  42
  43     fn target(&'a self, edge: &Self::Edge) -> Self::Node {
  44         edge.1
  45     }
  46 }
  47
  48 impl<'a> dot::Labeller<'a> for DropRangesBuilder {
  49     type Node = PostOrderId;
  50
  51     type Edge = (PostOrderId, PostOrderId);
  52
  53     fn graph_id(&'a self) -> dot::Id<'a> {
  54         dot::Id::new("drop_ranges").unwrap()
  55     }
  56
  57     fn node_id(&'a self, n: &Self::Node) -> dot::Id<'a> {
  58         dot::Id::new(format!("id{}", n.index())).unwrap()
  59     }
  60
  61     fn node_label(&'a self, n: &Self::Node) -> dot::LabelText<'a> {
  62         dot::LabelText::LabelStr(
  63             format!(
  64                 "{:?}, local_id: {}",
  65                 n,
  66                 self.post_order_map
  67                     .iter()
  68                     .find(|(_hir_id, &post_order_id)| post_order_id == *n)
  69                     .map_or("<unknown>".into(), |(hir_id, _)| format!(
  70                         "{}",
  71                         hir_id.local_id.index()
  72                     ))
  73             )
  74             .into(),
  75         )
  76     }
  77 }