src/librustc_incremental/assert_dep_graph.rs

   1 // Copyright 2012-2015 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 //! This pass is only used for the UNIT TESTS and DEBUGGING NEEDS
  12 //! around dependency graph construction. It serves two purposes; it
  13 //! will dump graphs in graphviz form to disk, and it searches for
  14 //! `#[rustc_if_this_changed]` and `#[rustc_then_this_would_need]`
  15 //! annotations. These annotations can be used to test whether paths
  16 //! exist in the graph. These checks run after trans, so they view the
  17 //! the final state of the dependency graph. Note that there are
  18 //! similar assertions found in `persist::dirty_clean` which check the
  19 //! **initial** state of the dependency graph, just after it has been
  20 //! loaded from disk.
  21 //!
  22 //! In this code, we report errors on each `rustc_if_this_changed`
  23 //! annotation. If a path exists in all cases, then we would report
  24 //! "all path(s) exist". Otherwise, we report: "no path to `foo`" for
  25 //! each case where no path exists.  `compile-fail` tests can then be
  26 //! used to check when paths exist or do not.
  27 //!
  28 //! The full form of the `rustc_if_this_changed` annotation is
  29 //! `#[rustc_if_this_changed(id)]`. The `"id"` is optional and
  30 //! defaults to `"id"` if omitted.
  31 //!
  32 //! Example:
  33 //!
  34 //! ```
  35 //! #[rustc_if_this_changed]
  36 //! fn foo() { }
  37 //!
  38 //! #[rustc_then_this_would_need("trans")] //~ ERROR no path from `foo`
  39 //! fn bar() { }
  40 //!
  41 //! #[rustc_then_this_would_need("trans")] //~ ERROR OK
  42 //! fn baz() { foo(); }
  43 //! ```
  44
  45 use graphviz as dot;
  46 use rustc::dep_graph::{DepGraphQuery, DepNode};
  47 use rustc::dep_graph::debug::{DepNodeFilter, EdgeFilter};
  48 use rustc::hir::def_id::DefId;
  49 use rustc::ty::TyCtxt;
  50 use rustc_data_structures::fnv::{FnvHashMap, FnvHashSet};
  51 use rustc_data_structures::graph::{Direction, INCOMING, OUTGOING, NodeIndex};
  52 use rustc::hir;
  53 use rustc::hir::intravisit::Visitor;
  54 use graphviz::IntoCow;
  55 use std::env;
  56 use std::fs::File;
  57 use std::io::Write;
  58 use syntax::ast;
  59 use syntax::parse::token::InternedString;
  60 use syntax_pos::Span;
  61
  62 const IF_THIS_CHANGED: &'static str = "rustc_if_this_changed";
  63 const THEN_THIS_WOULD_NEED: &'static str = "rustc_then_this_would_need";
  64 const ID: &'static str = "id";
  65
  66 pub fn assert_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
  67     let _ignore = tcx.dep_graph.in_ignore();
  68
  69     if tcx.sess.opts.debugging_opts.dump_dep_graph {
  70         dump_graph(tcx);
  71     }
  72
  73     // if the `rustc_attrs` feature is not enabled, then the
  74     // attributes we are interested in cannot be present anyway, so
  75     // skip the walk.
  76     if !tcx.sess.features.borrow().rustc_attrs {
  77         return;
  78     }
  79
  80     // Find annotations supplied by user (if any).
  81     let (if_this_changed, then_this_would_need) = {
  82         let mut visitor = IfThisChanged { tcx: tcx,
  83                                           if_this_changed: FnvHashMap(),
  84                                           then_this_would_need: FnvHashMap() };
  85         tcx.map.krate().visit_all_items(&mut visitor);
  86         (visitor.if_this_changed, visitor.then_this_would_need)
  87     };
  88
  89     if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
  90         assert!(tcx.sess.opts.debugging_opts.query_dep_graph,
  91                 "cannot use the `#[{}]` or `#[{}]` annotations \
  92                  without supplying `-Z query-dep-graph`",
  93                 IF_THIS_CHANGED, THEN_THIS_WOULD_NEED);
  94     }
  95
  96     // Check paths.
  97     check_paths(tcx, &if_this_changed, &then_this_would_need);
  98 }
  99
 100 type SourceHashMap =
 101     FnvHashMap<InternedString,
 102                FnvHashSet<(Span, DefId, DepNode<DefId>)>>;
 103 type TargetHashMap =
 104     FnvHashMap<InternedString,
 105                FnvHashSet<(Span, InternedString, ast::NodeId, DepNode<DefId>)>>;
 106
 107 struct IfThisChanged<'a, 'tcx:'a> {
 108     tcx: TyCtxt<'a, 'tcx, 'tcx>,
 109     if_this_changed: SourceHashMap,
 110     then_this_would_need: TargetHashMap,
 111 }
 112
 113 impl<'a, 'tcx> IfThisChanged<'a, 'tcx> {
 114     fn process_attrs(&mut self, node_id: ast::NodeId, def_id: DefId) {
 115         for attr in self.tcx.get_attrs(def_id).iter() {
 116             if attr.check_name(IF_THIS_CHANGED) {
 117                 let mut id = None;
 118                 for list_item in attr.meta_item_list().unwrap_or_default() {
 119                     match list_item.word() {
 120                         Some(word) if id.is_none() => {
 121                             id = Some(word.name().clone())
 122                         },
 123                         _ => {
 124                             // FIXME better-encapsulate meta_item (don't directly access `node`)
 125                             span_bug!(list_item.span(), "unexpected list-item {:?}", list_item.node)
 126                         }
 127                     }
 128                 }
 129
 130                 let id = id.unwrap_or(InternedString::new(ID));
 131                 self.if_this_changed.entry(id)
 132                                     .or_insert(FnvHashSet())
 133                                     .insert((attr.span, def_id, DepNode::Hir(def_id)));
 134             } else if attr.check_name(THEN_THIS_WOULD_NEED) {
 135                 let mut dep_node_interned = None;
 136                 let mut id = None;
 137                 for list_item in attr.meta_item_list().unwrap_or_default() {
 138                     match list_item.word() {
 139                         Some(word) if dep_node_interned.is_none() => {
 140                             dep_node_interned = Some(word.name().clone());
 141                         },
 142                         Some(word) if id.is_none() => {
 143                             id = Some(word.name().clone())
 144                         },
 145                         _ => {
 146                             // FIXME better-encapsulate meta_item (don't directly access `node`)
 147                             span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item.node)
 148                         }
 149                     }
 150                 }
 151
 152                 let dep_node = match dep_node_interned {
 153                     Some(ref n) => {
 154                         match DepNode::from_label_string(&n[..], def_id) {
 155                             Ok(n) => n,
 156                             Err(()) => {
 157                                 self.tcx.sess.span_fatal(
 158                                     attr.span,
 159                                     &format!("unrecognized DepNode variant {:?}", n));
 160                             }
 161                         }
 162                     }
 163                     None => {
 164                         self.tcx.sess.span_fatal(
 165                             attr.span,
 166                             &format!("missing DepNode variant"));
 167                     }
 168                 };
 169                 let id = id.unwrap_or(InternedString::new(ID));
 170                 self.then_this_would_need
 171                     .entry(id)
 172                     .or_insert(FnvHashSet())
 173                     .insert((attr.span, dep_node_interned.clone().unwrap(), node_id, dep_node));
 174             }
 175         }
 176     }
 177 }
 178
 179 impl<'a, 'tcx> Visitor<'tcx> for IfThisChanged<'a, 'tcx> {
 180     fn visit_item(&mut self, item: &'tcx hir::Item) {
 181         let def_id = self.tcx.map.local_def_id(item.id);
 182         self.process_attrs(item.id, def_id);
 183     }
 184 }
 185
 186 fn check_paths<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 187                          if_this_changed: &SourceHashMap,
 188                          then_this_would_need: &TargetHashMap)
 189 {
 190     // Return early here so as not to construct the query, which is not cheap.
 191     if if_this_changed.is_empty() {
 192         return;
 193     }
 194     let query = tcx.dep_graph.query();
 195     for (id, sources) in if_this_changed {
 196         let targets = match then_this_would_need.get(id) {
 197             Some(targets) => targets,
 198             None => {
 199                 for &(source_span, _, _) in sources.iter().take(1) {
 200                     tcx.sess.span_err(
 201                         source_span,
 202                         &format!("no targets for id `{}`", id));
 203                 }
 204                 continue;
 205             }
 206         };
 207
 208         for &(_, source_def_id, ref source_dep_node) in sources {
 209             let dependents = query.transitive_successors(source_dep_node);
 210             for &(target_span, ref target_pass, _, ref target_dep_node) in targets {
 211                 if !dependents.contains(&target_dep_node) {
 212                     tcx.sess.span_err(
 213                         target_span,
 214                         &format!("no path from `{}` to `{}`",
 215                                  tcx.item_path_str(source_def_id),
 216                                  target_pass));
 217                 } else {
 218                     tcx.sess.span_err(
 219                         target_span,
 220                         &format!("OK"));
 221                 }
 222             }
 223         }
 224     }
 225 }
 226
 227 fn dump_graph(tcx: TyCtxt) {
 228     let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| format!("dep_graph"));
 229     let query = tcx.dep_graph.query();
 230
 231     let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
 232         Ok(string) => {
 233             // Expect one of: "-> target", "source -> target", or "source ->".
 234             let edge_filter = EdgeFilter::new(&string).unwrap_or_else(|e| {
 235                 bug!("invalid filter: {}", e)
 236             });
 237             let sources = node_set(&query, &edge_filter.source);
 238             let targets = node_set(&query, &edge_filter.target);
 239             filter_nodes(&query, &sources, &targets)
 240         }
 241         Err(_) => {
 242             query.nodes()
 243                  .into_iter()
 244                  .collect()
 245         }
 246     };
 247     let edges = filter_edges(&query, &nodes);
 248
 249     { // dump a .txt file with just the edges:
 250         let txt_path = format!("{}.txt", path);
 251         let mut file = File::create(&txt_path).unwrap();
 252         for &(ref source, ref target) in &edges {
 253             write!(file, "{:?} -> {:?}\n", source, target).unwrap();
 254         }
 255     }
 256
 257     { // dump a .dot file in graphviz format:
 258         let dot_path = format!("{}.dot", path);
 259         let mut v = Vec::new();
 260         dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
 261         File::create(&dot_path).and_then(|mut f| f.write_all(&v)).unwrap();
 262     }
 263 }
 264
 265 pub struct GraphvizDepGraph<'q>(FnvHashSet<&'q DepNode<DefId>>,
 266                                 Vec<(&'q DepNode<DefId>, &'q DepNode<DefId>)>);
 267
 268 impl<'a, 'tcx, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
 269     type Node = &'q DepNode<DefId>;
 270     type Edge = (&'q DepNode<DefId>, &'q DepNode<DefId>);
 271     fn nodes(&self) -> dot::Nodes<&'q DepNode<DefId>> {
 272         let nodes: Vec<_> = self.0.iter().cloned().collect();
 273         nodes.into_cow()
 274     }
 275     fn edges(&self) -> dot::Edges<(&'q DepNode<DefId>, &'q DepNode<DefId>)> {
 276         self.1[..].into_cow()
 277     }
 278     fn source(&self, edge: &(&'q DepNode<DefId>, &'q DepNode<DefId>)) -> &'q DepNode<DefId> {
 279         edge.0
 280     }
 281     fn target(&self, edge: &(&'q DepNode<DefId>, &'q DepNode<DefId>)) -> &'q DepNode<DefId> {
 282         edge.1
 283     }
 284 }
 285
 286 impl<'a, 'tcx, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
 287     type Node = &'q DepNode<DefId>;
 288     type Edge = (&'q DepNode<DefId>, &'q DepNode<DefId>);
 289     fn graph_id(&self) -> dot::Id {
 290         dot::Id::new("DependencyGraph").unwrap()
 291     }
 292     fn node_id(&self, n: &&'q DepNode<DefId>) -> dot::Id {
 293         let s: String =
 294             format!("{:?}", n).chars()
 295                               .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
 296                               .collect();
 297         debug!("n={:?} s={:?}", n, s);
 298         dot::Id::new(s).unwrap()
 299     }
 300     fn node_label(&self, n: &&'q DepNode<DefId>) -> dot::LabelText {
 301         dot::LabelText::label(format!("{:?}", n))
 302     }
 303 }
 304
 305 // Given an optional filter like `"x,y,z"`, returns either `None` (no
 306 // filter) or the set of nodes whose labels contain all of those
 307 // substrings.
 308 fn node_set<'q>(query: &'q DepGraphQuery<DefId>, filter: &DepNodeFilter)
 309                 -> Option<FnvHashSet<&'q DepNode<DefId>>>
 310 {
 311     debug!("node_set(filter={:?})", filter);
 312
 313     if filter.accepts_all() {
 314         return None;
 315     }
 316
 317     Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
 318 }
 319
 320 fn filter_nodes<'q>(query: &'q DepGraphQuery<DefId>,
 321                     sources: &Option<FnvHashSet<&'q DepNode<DefId>>>,
 322                     targets: &Option<FnvHashSet<&'q DepNode<DefId>>>)
 323                     -> FnvHashSet<&'q DepNode<DefId>>
 324 {
 325     if let &Some(ref sources) = sources {
 326         if let &Some(ref targets) = targets {
 327             walk_between(query, sources, targets)
 328         } else {
 329             walk_nodes(query, sources, OUTGOING)
 330         }
 331     } else if let &Some(ref targets) = targets {
 332         walk_nodes(query, targets, INCOMING)
 333     } else {
 334         query.nodes().into_iter().collect()
 335     }
 336 }
 337
 338 fn walk_nodes<'q>(query: &'q DepGraphQuery<DefId>,
 339                   starts: &FnvHashSet<&'q DepNode<DefId>>,
 340                   direction: Direction)
 341                   -> FnvHashSet<&'q DepNode<DefId>>
 342 {
 343     let mut set = FnvHashSet();
 344     for &start in starts {
 345         debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
 346         if set.insert(start) {
 347             let mut stack = vec![query.indices[start]];
 348             while let Some(index) = stack.pop() {
 349                 for (_, edge) in query.graph.adjacent_edges(index, direction) {
 350                     let neighbor_index = edge.source_or_target(direction);
 351                     let neighbor = query.graph.node_data(neighbor_index);
 352                     if set.insert(neighbor) {
 353                         stack.push(neighbor_index);
 354                     }
 355                 }
 356             }
 357         }
 358     }
 359     set
 360 }
 361
 362 fn walk_between<'q>(query: &'q DepGraphQuery<DefId>,
 363                     sources: &FnvHashSet<&'q DepNode<DefId>>,
 364                     targets: &FnvHashSet<&'q DepNode<DefId>>)
 365                     -> FnvHashSet<&'q DepNode<DefId>>
 366 {
 367     // This is a bit tricky. We want to include a node only if it is:
 368     // (a) reachable from a source and (b) will reach a target. And we
 369     // have to be careful about cycles etc.  Luckily efficiency is not
 370     // a big concern!
 371
 372     #[derive(Copy, Clone, PartialEq)]
 373     enum State { Undecided, Deciding, Included, Excluded }
 374
 375     let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
 376
 377     for &target in targets {
 378         node_states[query.indices[target].0] = State::Included;
 379     }
 380
 381     for source in sources.iter().map(|&n| query.indices[n]) {
 382         recurse(query, &mut node_states, source);
 383     }
 384
 385     return query.nodes()
 386                 .into_iter()
 387                 .filter(|&n| {
 388                     let index = query.indices[n];
 389                     node_states[index.0] == State::Included
 390                 })
 391                 .collect();
 392
 393     fn recurse(query: &DepGraphQuery<DefId>,
 394                node_states: &mut [State],
 395                node: NodeIndex)
 396                -> bool
 397     {
 398         match node_states[node.0] {
 399             // known to reach a target
 400             State::Included => return true,
 401
 402             // known not to reach a target
 403             State::Excluded => return false,
 404
 405             // backedge, not yet known, say false
 406             State::Deciding => return false,
 407
 408             State::Undecided => { }
 409         }
 410
 411         node_states[node.0] = State::Deciding;
 412
 413         for neighbor_index in query.graph.successor_nodes(node) {
 414             if recurse(query, node_states, neighbor_index) {
 415                 node_states[node.0] = State::Included;
 416             }
 417         }
 418
 419         // if we didn't find a path to target, then set to excluded
 420         if node_states[node.0] == State::Deciding {
 421             node_states[node.0] = State::Excluded;
 422             false
 423         } else {
 424             assert!(node_states[node.0] == State::Included);
 425             true
 426         }
 427     }
 428 }
 429
 430 fn filter_edges<'q>(query: &'q DepGraphQuery<DefId>,
 431                     nodes: &FnvHashSet<&'q DepNode<DefId>>)
 432                     -> Vec<(&'q DepNode<DefId>, &'q DepNode<DefId>)>
 433 {
 434     query.edges()
 435          .into_iter()
 436          .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))
 437          .collect()
 438 }