src/librustc/cfg/mod.rs

   1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! Module that constructs a control-flow graph representing an item.
  12 //! Uses `Graph` as the underlying representation.
  13
  14 use rustc_data_structures::graph;
  15 use ty::TyCtxt;
  16 use syntax::ast;
  17 use hir;
  18
  19 mod construct;
  20 pub mod graphviz;
  21
  22 pub struct CFG {
  23     pub graph: CFGGraph,
  24     pub entry: CFGIndex,
  25     pub exit: CFGIndex,
  26 }
  27
  28 #[derive(Copy, Clone, Debug, PartialEq)]
  29 pub enum CFGNodeData {
  30     AST(ast::NodeId),
  31     Entry,
  32     Exit,
  33     Dummy,
  34     Unreachable,
  35 }
  36
  37 impl CFGNodeData {
  38     pub fn id(&self) -> ast::NodeId {
  39         if let CFGNodeData::AST(id) = *self {
  40             id
  41         } else {
  42             ast::DUMMY_NODE_ID
  43         }
  44     }
  45 }
  46
  47 #[derive(Debug)]
  48 pub struct CFGEdgeData {
  49     pub exiting_scopes: Vec<ast::NodeId>
  50 }
  51
  52 pub type CFGIndex = graph::NodeIndex;
  53
  54 pub type CFGGraph = graph::Graph<CFGNodeData, CFGEdgeData>;
  55
  56 pub type CFGNode = graph::Node<CFGNodeData>;
  57
  58 pub type CFGEdge = graph::Edge<CFGEdgeData>;
  59
  60 impl CFG {
  61     pub fn new(tcx: &TyCtxt,
  62                blk: &hir::Block) -> CFG {
  63         construct::construct(tcx, blk)
  64     }
  65
  66     pub fn node_is_reachable(&self, id: ast::NodeId) -> bool {
  67         self.graph.depth_traverse(self.entry)
  68                   .any(|idx| self.graph.node_data(idx).id() == id)
  69     }
  70 }