src/librustc/middle/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 middle::ty;
  16 use syntax::ast;
  17
  18 mod construct;
  19 pub mod graphviz;
  20
  21 pub struct CFG {
  22     pub graph: CFGGraph,
  23     pub entry: CFGIndex,
  24     pub exit: CFGIndex,
  25 }
  26
  27 #[derive(Copy, Clone, Debug, PartialEq)]
  28 pub enum CFGNodeData {
  29     AST(ast::NodeId),
  30     Entry,
  31     Exit,
  32     Dummy,
  33     Unreachable,
  34 }
  35
  36 impl CFGNodeData {
  37     pub fn id(&self) -> ast::NodeId {
  38         if let CFGNodeData::AST(id) = *self {
  39             id
  40         } else {
  41             ast::DUMMY_NODE_ID
  42         }
  43     }
  44 }
  45
  46 #[derive(Debug)]
  47 pub struct CFGEdgeData {
  48     pub exiting_scopes: Vec<ast::NodeId>
  49 }
  50
  51 pub type CFGIndex = graph::NodeIndex;
  52
  53 pub type CFGGraph = graph::Graph<CFGNodeData, CFGEdgeData>;
  54
  55 pub type CFGNode = graph::Node<CFGNodeData>;
  56
  57 pub type CFGEdge = graph::Edge<CFGEdgeData>;
  58
  59 impl CFG {
  60     pub fn new(tcx: &ty::ctxt,
  61                blk: &ast::Block) -> CFG {
  62         construct::construct(tcx, blk)
  63     }
  64
  65     pub fn node_is_reachable(&self, id: ast::NodeId) -> bool {
  66         self.graph.depth_traverse(self.entry).any(|node| node.id() == id)
  67     }
  68 }