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