1 // Copyright 2014 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.
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.
11 //! This module provides linkage between libgraphviz traits and
12 //! `rustc::middle::typeck::infer::region_inference`, generating a
13 //! rendering of the graph represented by the list of `Constraint`
14 //! instances (which make up the edges of the graph), as well as the
15 //! origin for each constraint (which are attached to the labels on
18 /// For clarity, rename the graphviz crate locally to dot.
21 use ty::{self, TyCtxt};
22 use middle::region::CodeExtent;
23 use super::Constraint;
24 use infer::SubregionOrigin;
25 use infer::region_inference::RegionVarBindings;
26 use util::nodemap::{FxHashMap, FxHashSet};
29 use std::collections::hash_map::Entry::Vacant;
33 use std::io::prelude::*;
34 use std::sync::atomic::{AtomicBool, Ordering};
37 fn print_help_message() {
39 -Z print-region-graph by default prints a region constraint graph for every \n\
40 function body, to the path `/tmp/constraints.nodeXXX.dot`, where the XXX is \n\
41 replaced with the node id of the function under analysis. \n\
43 To select one particular function body, set `RUST_REGION_GRAPH_NODE=XXX`, \n\
44 where XXX is the node id desired. \n\
46 To generate output to some path other than the default \n\
47 `/tmp/constraints.nodeXXX.dot`, set `RUST_REGION_GRAPH=/path/desired.dot`; \n\
48 occurrences of the character `%` in the requested path will be replaced with\n\
49 the node id of the function under analysis. \n\
51 (Since you requested help via RUST_REGION_GRAPH=help, no region constraint \n\
52 graphs will be printed. \n\
56 pub fn maybe_print_constraints_for<'a, 'gcx, 'tcx>(
57 region_vars: &RegionVarBindings<'a, 'gcx, 'tcx>,
58 subject_node: ast::NodeId)
60 let tcx = region_vars.tcx;
62 if !region_vars.tcx.sess.opts.debugging_opts.print_region_graph {
66 let requested_node = env::var("RUST_REGION_GRAPH_NODE")
67 .ok().and_then(|s| s.parse().map(ast::NodeId::new).ok());
69 if requested_node.is_some() && requested_node != Some(subject_node) {
73 let requested_output = env::var("RUST_REGION_GRAPH");
74 debug!("requested_output: {:?} requested_node: {:?}",
79 let output_template = match requested_output {
80 Ok(ref s) if s == "help" => {
81 static PRINTED_YET: AtomicBool = AtomicBool::new(false);
82 if !PRINTED_YET.load(Ordering::SeqCst) {
84 PRINTED_YET.store(true, Ordering::SeqCst);
89 Ok(other_path) => other_path,
90 Err(_) => "/tmp/constraints.node%.dot".to_string(),
93 if output_template.is_empty() {
94 panic!("empty string provided as RUST_REGION_GRAPH");
97 if output_template.contains('%') {
98 let mut new_str = String::new();
99 for c in output_template.chars() {
101 new_str.push_str(&subject_node.to_string());
112 let constraints = &*region_vars.constraints.borrow();
113 match dump_region_constraints_to(tcx, constraints, &output_path) {
116 let msg = format!("io error dumping region constraints: {}", e);
117 region_vars.tcx.sess.err(&msg)
122 struct ConstraintGraph<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
123 tcx: TyCtxt<'a, 'gcx, 'tcx>,
125 map: &'a FxHashMap<Constraint<'tcx>, SubregionOrigin<'tcx>>,
126 node_ids: FxHashMap<Node, usize>,
129 #[derive(Clone, Hash, PartialEq, Eq, Debug, Copy)]
131 RegionVid(ty::RegionVid),
135 // type Edge = Constraint;
136 #[derive(Clone, PartialEq, Eq, Debug, Copy)]
138 Constraint(Constraint<'tcx>),
139 EnclScope(CodeExtent, CodeExtent),
142 impl<'a, 'gcx, 'tcx> ConstraintGraph<'a, 'gcx, 'tcx> {
143 fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
145 map: &'a ConstraintMap<'tcx>)
146 -> ConstraintGraph<'a, 'gcx, 'tcx> {
148 let mut node_ids = FxHashMap();
150 let mut add_node = |node| {
151 if let Vacant(e) = node_ids.entry(node) {
157 for (n1, n2) in map.keys().map(|c| constraint_to_nodes(c)) {
162 tcx.region_maps.each_encl_scope(|sub, sup| {
163 add_node(Node::Region(ty::ReScope(*sub)));
164 add_node(Node::Region(ty::ReScope(*sup)));
177 impl<'a, 'gcx, 'tcx> dot::Labeller<'a> for ConstraintGraph<'a, 'gcx, 'tcx> {
179 type Edge = Edge<'tcx>;
180 fn graph_id(&self) -> dot::Id {
181 dot::Id::new(&*self.graph_name).unwrap()
183 fn node_id(&self, n: &Node) -> dot::Id {
184 let node_id = match self.node_ids.get(n) {
185 Some(node_id) => node_id,
186 None => bug!("no node_id found for node: {:?}", n),
188 let name = || format!("node_{}", node_id);
189 match dot::Id::new(name()) {
192 bug!("failed to create graphviz node identified by {}", name());
196 fn node_label(&self, n: &Node) -> dot::LabelText {
198 Node::RegionVid(n_vid) => dot::LabelText::label(format!("{:?}", n_vid)),
199 Node::Region(n_rgn) => dot::LabelText::label(format!("{:?}", n_rgn)),
202 fn edge_label(&self, e: &Edge) -> dot::LabelText {
204 Edge::Constraint(ref c) =>
205 dot::LabelText::label(format!("{:?}", self.map.get(c).unwrap())),
206 Edge::EnclScope(..) => dot::LabelText::label(format!("(enclosed)")),
211 fn constraint_to_nodes(c: &Constraint) -> (Node, Node) {
213 Constraint::ConstrainVarSubVar(rv_1, rv_2) =>
214 (Node::RegionVid(rv_1), Node::RegionVid(rv_2)),
215 Constraint::ConstrainRegSubVar(r_1, rv_2) =>
216 (Node::Region(*r_1), Node::RegionVid(rv_2)),
217 Constraint::ConstrainVarSubReg(rv_1, r_2) =>
218 (Node::RegionVid(rv_1), Node::Region(*r_2)),
219 Constraint::ConstrainRegSubReg(r_1, r_2) =>
220 (Node::Region(*r_1), Node::Region(*r_2)),
224 fn edge_to_nodes(e: &Edge) -> (Node, Node) {
226 Edge::Constraint(ref c) => constraint_to_nodes(c),
227 Edge::EnclScope(sub, sup) => {
228 (Node::Region(ty::ReScope(sub)),
229 Node::Region(ty::ReScope(sup)))
234 impl<'a, 'gcx, 'tcx> dot::GraphWalk<'a> for ConstraintGraph<'a, 'gcx, 'tcx> {
236 type Edge = Edge<'tcx>;
237 fn nodes(&self) -> dot::Nodes<Node> {
238 let mut set = FxHashSet();
239 for node in self.node_ids.keys() {
242 debug!("constraint graph has {} nodes", set.len());
243 set.into_iter().collect()
245 fn edges(&self) -> dot::Edges<Edge<'tcx>> {
246 debug!("constraint graph has {} edges", self.map.len());
247 let mut v: Vec<_> = self.map.keys().map(|e| Edge::Constraint(*e)).collect();
248 self.tcx.region_maps.each_encl_scope(|sub, sup| v.push(Edge::EnclScope(*sub, *sup)));
249 debug!("region graph has {} edges", v.len());
252 fn source(&self, edge: &Edge<'tcx>) -> Node {
253 let (n1, _) = edge_to_nodes(edge);
254 debug!("edge {:?} has source {:?}", edge, n1);
257 fn target(&self, edge: &Edge<'tcx>) -> Node {
258 let (_, n2) = edge_to_nodes(edge);
259 debug!("edge {:?} has target {:?}", edge, n2);
264 pub type ConstraintMap<'tcx> = FxHashMap<Constraint<'tcx>, SubregionOrigin<'tcx>>;
266 fn dump_region_constraints_to<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
267 map: &ConstraintMap<'tcx>,
270 debug!("dump_region_constraints map (len: {}) path: {}",
273 let g = ConstraintGraph::new(tcx, format!("region_constraints"), map);
274 debug!("dump_region_constraints calling render");
275 let mut v = Vec::new();
276 dot::render(&g, &mut v).unwrap();
277 File::create(path).and_then(|mut f| f.write_all(&v))