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 codegen, 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("foo")]`, which will report a
  30 //! source node of `foo(def_id)`. The `"foo"` is optional and
  31 //! defaults to `"Hir"` if omitted.
  32 //!
  33 //! Example:
  34 //!
  35 //! ```
  36 //! #[rustc_if_this_changed(Hir)]
  37 //! fn foo() { }
  38 //!
  39 //! #[rustc_then_this_would_need(codegen)] //~ ERROR no path from `foo`
  40 //! fn bar() { }
  41 //!
  42 //! #[rustc_then_this_would_need(codegen)] //~ ERROR OK
  43 //! fn baz() { foo(); }
  44 //! ```
  45
  46 use graphviz as dot;
  47 use rustc::dep_graph::{DepGraphQuery, DepNode, DepKind};
  48 use rustc::dep_graph::debug::{DepNodeFilter, EdgeFilter};
  49 use rustc::hir::def_id::DefId;
  50 use rustc::ty::TyCtxt;
  51 use rustc_data_structures::fx::FxHashSet;
  52 use rustc_data_structures::graph::implementation::{
  53     Direction, INCOMING, OUTGOING, NodeIndex
  54 };
  55 use rustc::hir;
  56 use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
  57 use rustc::ich::{ATTR_IF_THIS_CHANGED, ATTR_THEN_THIS_WOULD_NEED};
  58 use std::env;
  59 use std::fs::{self, File};
  60 use std::io::Write;
  61 use syntax::ast;
  62 use syntax_pos::Span;
  63
  64 pub fn assert_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
  65     tcx.dep_graph.with_ignore(|| {
  66         if tcx.sess.opts.debugging_opts.dump_dep_graph {
  67             dump_graph(tcx);
  68         }
  69
  70         // if the `rustc_attrs` feature is not enabled, then the
  71         // attributes we are interested in cannot be present anyway, so
  72         // skip the walk.
  73         if !tcx.features().rustc_attrs {
  74             return;
  75         }
  76
  77         // Find annotations supplied by user (if any).
  78         let (if_this_changed, then_this_would_need) = {
  79             let mut visitor = IfThisChanged { tcx,
  80                                             if_this_changed: vec![],
  81                                             then_this_would_need: vec![] };
  82             visitor.process_attrs(ast::CRATE_NODE_ID, &tcx.hir.krate().attrs);
  83             tcx.hir.krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
  84             (visitor.if_this_changed, visitor.then_this_would_need)
  85         };
  86
  87         if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
  88             assert!(tcx.sess.opts.debugging_opts.query_dep_graph,
  89                     "cannot use the `#[{}]` or `#[{}]` annotations \
  90                     without supplying `-Z query-dep-graph`",
  91                     ATTR_IF_THIS_CHANGED, ATTR_THEN_THIS_WOULD_NEED);
  92         }
  93
  94         // Check paths.
  95         check_paths(tcx, &if_this_changed, &then_this_would_need);
  96     })
  97 }
  98
  99 type Sources = Vec<(Span, DefId, DepNode)>;
 100 type Targets = Vec<(Span, ast::Name, ast::NodeId, DepNode)>;
 101
 102 struct IfThisChanged<'a, 'tcx:'a> {
 103     tcx: TyCtxt<'a, 'tcx, 'tcx>,
 104     if_this_changed: Sources,
 105     then_this_would_need: Targets,
 106 }
 107
 108 impl<'a, 'tcx> IfThisChanged<'a, 'tcx> {
 109     fn argument(&self, attr: &ast::Attribute) -> Option<ast::Name> {
 110         let mut value = None;
 111         for list_item in attr.meta_item_list().unwrap_or_default() {
 112             match list_item.word() {
 113                 Some(word) if value.is_none() =>
 114                     value = Some(word.name()),
 115                 _ =>
 116                     // FIXME better-encapsulate meta_item (don't directly access `node`)
 117                     span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item.node),
 118             }
 119         }
 120         value
 121     }
 122
 123     fn process_attrs(&mut self, node_id: ast::NodeId, attrs: &[ast::Attribute]) {
 124         let def_id = self.tcx.hir.local_def_id(node_id);
 125         let def_path_hash = self.tcx.def_path_hash(def_id);
 126         for attr in attrs {
 127             if attr.check_name(ATTR_IF_THIS_CHANGED) {
 128                 let dep_node_interned = self.argument(attr);
 129                 let dep_node = match dep_node_interned {
 130                     None => def_path_hash.to_dep_node(DepKind::Hir),
 131                     Some(n) => {
 132                         match DepNode::from_label_string(&n.as_str(), def_path_hash) {
 133                             Ok(n) => n,
 134                             Err(()) => {
 135                                 self.tcx.sess.span_fatal(
 136                                     attr.span,
 137                                     &format!("unrecognized DepNode variant {:?}", n));
 138                             }
 139                         }
 140                     }
 141                 };
 142                 self.if_this_changed.push((attr.span, def_id, dep_node));
 143             } else if attr.check_name(ATTR_THEN_THIS_WOULD_NEED) {
 144                 let dep_node_interned = self.argument(attr);
 145                 let dep_node = match dep_node_interned {
 146                     Some(n) => {
 147                         match DepNode::from_label_string(&n.as_str(), def_path_hash) {
 148                             Ok(n) => n,
 149                             Err(()) => {
 150                                 self.tcx.sess.span_fatal(
 151                                     attr.span,
 152                                     &format!("unrecognized DepNode variant {:?}", n));
 153                             }
 154                         }
 155                     }
 156                     None => {
 157                         self.tcx.sess.span_fatal(
 158                             attr.span,
 159                             "missing DepNode variant");
 160                     }
 161                 };
 162                 self.then_this_would_need.push((attr.span,
 163                                                 dep_node_interned.unwrap(),
 164                                                 node_id,
 165                                                 dep_node));
 166             }
 167         }
 168     }
 169 }
 170
 171 impl<'a, 'tcx> Visitor<'tcx> for IfThisChanged<'a, 'tcx> {
 172     fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
 173         NestedVisitorMap::OnlyBodies(&self.tcx.hir)
 174     }
 175
 176     fn visit_item(&mut self, item: &'tcx hir::Item) {
 177         self.process_attrs(item.id, &item.attrs);
 178         intravisit::walk_item(self, item);
 179     }
 180
 181     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
 182         self.process_attrs(trait_item.id, &trait_item.attrs);
 183         intravisit::walk_trait_item(self, trait_item);
 184     }
 185
 186     fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
 187         self.process_attrs(impl_item.id, &impl_item.attrs);
 188         intravisit::walk_impl_item(self, impl_item);
 189     }
 190
 191     fn visit_struct_field(&mut self, s: &'tcx hir::StructField) {
 192         self.process_attrs(s.id, &s.attrs);
 193         intravisit::walk_struct_field(self, s);
 194     }
 195 }
 196
 197 fn check_paths<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 198                          if_this_changed: &Sources,
 199                          then_this_would_need: &Targets)
 200 {
 201     // Return early here so as not to construct the query, which is not cheap.
 202     if if_this_changed.is_empty() {
 203         for &(target_span, _, _, _) in then_this_would_need {
 204             tcx.sess.span_err(
 205                 target_span,
 206                 "no #[rustc_if_this_changed] annotation detected");
 207
 208         }
 209         return;
 210     }
 211     let query = tcx.dep_graph.query();
 212     for &(_, source_def_id, ref source_dep_node) in if_this_changed {
 213         let dependents = query.transitive_predecessors(source_dep_node);
 214         for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
 215             if !dependents.contains(&target_dep_node) {
 216                 tcx.sess.span_err(
 217                     target_span,
 218                     &format!("no path from `{}` to `{}`",
 219                              tcx.item_path_str(source_def_id),
 220                              target_pass));
 221             } else {
 222                 tcx.sess.span_err(
 223                     target_span,
 224                     "OK");
 225             }
 226         }
 227     }
 228 }
 229
 230 fn dump_graph(tcx: TyCtxt) {
 231     let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
 232     let query = tcx.dep_graph.query();
 233
 234     let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
 235         Ok(string) => {
 236             // Expect one of: "-> target", "source -> target", or "source ->".
 237             let edge_filter = EdgeFilter::new(&string).unwrap_or_else(|e| {
 238                 bug!("invalid filter: {}", e)
 239             });
 240             let sources = node_set(&query, &edge_filter.source);
 241             let targets = node_set(&query, &edge_filter.target);
 242             filter_nodes(&query, &sources, &targets)
 243         }
 244         Err(_) => {
 245             query.nodes()
 246                  .into_iter()
 247                  .collect()
 248         }
 249     };
 250     let edges = filter_edges(&query, &nodes);
 251
 252     { // dump a .txt file with just the edges:
 253         let txt_path = format!("{}.txt", path);
 254         let mut file = File::create(&txt_path).unwrap();
 255         for &(ref source, ref target) in &edges {
 256             write!(file, "{:?} -> {:?}\n", source, target).unwrap();
 257         }
 258     }
 259
 260     { // dump a .dot file in graphviz format:
 261         let dot_path = format!("{}.dot", path);
 262         let mut v = Vec::new();
 263         dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
 264         fs::write(dot_path, v).unwrap();
 265     }
 266 }
 267
 268 pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>,
 269                                 Vec<(&'q DepNode, &'q DepNode)>);
 270
 271 impl<'a, 'tcx, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
 272     type Node = &'q DepNode;
 273     type Edge = (&'q DepNode, &'q DepNode);
 274     fn nodes(&self) -> dot::Nodes<&'q DepNode> {
 275         let nodes: Vec<_> = self.0.iter().cloned().collect();
 276         nodes.into()
 277     }
 278     fn edges(&self) -> dot::Edges<(&'q DepNode, &'q DepNode)> {
 279         self.1[..].into()
 280     }
 281     fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
 282         edge.0
 283     }
 284     fn target(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
 285         edge.1
 286     }
 287 }
 288
 289 impl<'a, 'tcx, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
 290     type Node = &'q DepNode;
 291     type Edge = (&'q DepNode, &'q DepNode);
 292     fn graph_id(&self) -> dot::Id {
 293         dot::Id::new("DependencyGraph").unwrap()
 294     }
 295     fn node_id(&self, n: &&'q DepNode) -> dot::Id {
 296         let s: String =
 297             format!("{:?}", n).chars()
 298                               .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
 299                               .collect();
 300         debug!("n={:?} s={:?}", n, s);
 301         dot::Id::new(s).unwrap()
 302     }
 303     fn node_label(&self, n: &&'q DepNode) -> dot::LabelText {
 304         dot::LabelText::label(format!("{:?}", n))
 305     }
 306 }
 307
 308 // Given an optional filter like `"x,y,z"`, returns either `None` (no
 309 // filter) or the set of nodes whose labels contain all of those
 310 // substrings.
 311 fn node_set<'q>(query: &'q DepGraphQuery, filter: &DepNodeFilter)
 312                 -> Option<FxHashSet<&'q DepNode>>
 313 {
 314     debug!("node_set(filter={:?})", filter);
 315
 316     if filter.accepts_all() {
 317         return None;
 318     }
 319
 320     Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
 321 }
 322
 323 fn filter_nodes<'q>(query: &'q DepGraphQuery,
 324                     sources: &Option<FxHashSet<&'q DepNode>>,
 325                     targets: &Option<FxHashSet<&'q DepNode>>)
 326                     -> FxHashSet<&'q DepNode>
 327 {
 328     if let &Some(ref sources) = sources {
 329         if let &Some(ref targets) = targets {
 330             walk_between(query, sources, targets)
 331         } else {
 332             walk_nodes(query, sources, OUTGOING)
 333         }
 334     } else if let &Some(ref targets) = targets {
 335         walk_nodes(query, targets, INCOMING)
 336     } else {
 337         query.nodes().into_iter().collect()
 338     }
 339 }
 340
 341 fn walk_nodes<'q>(query: &'q DepGraphQuery,
 342                   starts: &FxHashSet<&'q DepNode>,
 343                   direction: Direction)
 344                   -> FxHashSet<&'q DepNode>
 345 {
 346     let mut set = FxHashSet();
 347     for &start in starts {
 348         debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
 349         if set.insert(start) {
 350             let mut stack = vec![query.indices[start]];
 351             while let Some(index) = stack.pop() {
 352                 for (_, edge) in query.graph.adjacent_edges(index, direction) {
 353                     let neighbor_index = edge.source_or_target(direction);
 354                     let neighbor = query.graph.node_data(neighbor_index);
 355                     if set.insert(neighbor) {
 356                         stack.push(neighbor_index);
 357                     }
 358                 }
 359             }
 360         }
 361     }
 362     set
 363 }
 364
 365 fn walk_between<'q>(query: &'q DepGraphQuery,
 366                     sources: &FxHashSet<&'q DepNode>,
 367                     targets: &FxHashSet<&'q DepNode>)
 368                     -> FxHashSet<&'q DepNode>
 369 {
 370     // This is a bit tricky. We want to include a node only if it is:
 371     // (a) reachable from a source and (b) will reach a target. And we
 372     // have to be careful about cycles etc.  Luckily efficiency is not
 373     // a big concern!
 374
 375     #[derive(Copy, Clone, PartialEq)]
 376     enum State { Undecided, Deciding, Included, Excluded }
 377
 378     let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
 379
 380     for &target in targets {
 381         node_states[query.indices[target].0] = State::Included;
 382     }
 383
 384     for source in sources.iter().map(|&n| query.indices[n]) {
 385         recurse(query, &mut node_states, source);
 386     }
 387
 388     return query.nodes()
 389                 .into_iter()
 390                 .filter(|&n| {
 391                     let index = query.indices[n];
 392                     node_states[index.0] == State::Included
 393                 })
 394                 .collect();
 395
 396     fn recurse(query: &DepGraphQuery,
 397                node_states: &mut [State],
 398                node: NodeIndex)
 399                -> bool
 400     {
 401         match node_states[node.0] {
 402             // known to reach a target
 403             State::Included => return true,
 404
 405             // known not to reach a target
 406             State::Excluded => return false,
 407
 408             // backedge, not yet known, say false
 409             State::Deciding => return false,
 410
 411             State::Undecided => { }
 412         }
 413
 414         node_states[node.0] = State::Deciding;
 415
 416         for neighbor_index in query.graph.successor_nodes(node) {
 417             if recurse(query, node_states, neighbor_index) {
 418                 node_states[node.0] = State::Included;
 419             }
 420         }
 421
 422         // if we didn't find a path to target, then set to excluded
 423         if node_states[node.0] == State::Deciding {
 424             node_states[node.0] = State::Excluded;
 425             false
 426         } else {
 427             assert!(node_states[node.0] == State::Included);
 428             true
 429         }
 430     }
 431 }
 432
 433 fn filter_edges<'q>(query: &'q DepGraphQuery,
 434                     nodes: &FxHashSet<&'q DepNode>)
 435                     -> Vec<(&'q DepNode, &'q DepNode)>
 436 {
 437     query.edges()
 438          .into_iter()
 439          .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))
 440          .collect()
 441 }