compiler/rustc_incremental/src/assert_dep_graph.rs

   1 //! This pass is only used for the UNIT TESTS and DEBUGGING NEEDS
   2 //! around dependency graph construction. It serves two purposes; it
   3 //! will dump graphs in graphviz form to disk, and it searches for
   4 //! `#[rustc_if_this_changed]` and `#[rustc_then_this_would_need]`
   5 //! annotations. These annotations can be used to test whether paths
   6 //! exist in the graph. These checks run after codegen, so they view the
   7 //! the final state of the dependency graph. Note that there are
   8 //! similar assertions found in `persist::dirty_clean` which check the
   9 //! **initial** state of the dependency graph, just after it has been
  10 //! loaded from disk.
  11 //!
  12 //! In this code, we report errors on each `rustc_if_this_changed`
  13 //! annotation. If a path exists in all cases, then we would report
  14 //! "all path(s) exist". Otherwise, we report: "no path to `foo`" for
  15 //! each case where no path exists. `ui` tests can then be
  16 //! used to check when paths exist or do not.
  17 //!
  18 //! The full form of the `rustc_if_this_changed` annotation is
  19 //! `#[rustc_if_this_changed("foo")]`, which will report a
  20 //! source node of `foo(def_id)`. The `"foo"` is optional and
  21 //! defaults to `"Hir"` if omitted.
  22 //!
  23 //! Example:
  24 //!
  25 //! ```
  26 //! #[rustc_if_this_changed(Hir)]
  27 //! fn foo() { }
  28 //!
  29 //! #[rustc_then_this_would_need(codegen)] //~ ERROR no path from `foo`
  30 //! fn bar() { }
  31 //!
  32 //! #[rustc_then_this_would_need(codegen)] //~ ERROR OK
  33 //! fn baz() { foo(); }
  34 //! ```
  35
  36 use rustc_ast as ast;
  37 use rustc_data_structures::fx::FxHashSet;
  38 use rustc_data_structures::graph::implementation::{Direction, NodeIndex, INCOMING, OUTGOING};
  39 use rustc_graphviz as dot;
  40 use rustc_hir as hir;
  41 use rustc_hir::def_id::DefId;
  42 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
  43 use rustc_middle::dep_graph::{
  44     DepGraphQuery, DepKind, DepNode, DepNodeExt, DepNodeFilter, EdgeFilter,
  45 };
  46 use rustc_middle::hir::map::Map;
  47 use rustc_middle::ty::TyCtxt;
  48 use rustc_span::symbol::{sym, Symbol};
  49 use rustc_span::Span;
  50
  51 use std::env;
  52 use std::fs::{self, File};
  53 use std::io::{BufWriter, Write};
  54
  55 pub fn assert_dep_graph(tcx: TyCtxt<'_>) {
  56     tcx.dep_graph.with_ignore(|| {
  57         if tcx.sess.opts.debugging_opts.dump_dep_graph {
  58             tcx.dep_graph.with_query(dump_graph);
  59         }
  60
  61         if !tcx.sess.opts.debugging_opts.query_dep_graph {
  62             return;
  63         }
  64
  65         // if the `rustc_attrs` feature is not enabled, then the
  66         // attributes we are interested in cannot be present anyway, so
  67         // skip the walk.
  68         if !tcx.features().rustc_attrs {
  69             return;
  70         }
  71
  72         // Find annotations supplied by user (if any).
  73         let (if_this_changed, then_this_would_need) = {
  74             let mut visitor =
  75                 IfThisChanged { tcx, if_this_changed: vec![], then_this_would_need: vec![] };
  76             visitor.process_attrs(hir::CRATE_HIR_ID);
  77             tcx.hir().krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
  78             (visitor.if_this_changed, visitor.then_this_would_need)
  79         };
  80
  81         if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
  82             assert!(
  83                 tcx.sess.opts.debugging_opts.query_dep_graph,
  84                 "cannot use the `#[{}]` or `#[{}]` annotations \
  85                     without supplying `-Z query-dep-graph`",
  86                 sym::rustc_if_this_changed,
  87                 sym::rustc_then_this_would_need
  88             );
  89         }
  90
  91         // Check paths.
  92         check_paths(tcx, &if_this_changed, &then_this_would_need);
  93     })
  94 }
  95
  96 type Sources = Vec<(Span, DefId, DepNode)>;
  97 type Targets = Vec<(Span, Symbol, hir::HirId, DepNode)>;
  98
  99 struct IfThisChanged<'tcx> {
 100     tcx: TyCtxt<'tcx>,
 101     if_this_changed: Sources,
 102     then_this_would_need: Targets,
 103 }
 104
 105 impl IfThisChanged<'tcx> {
 106     fn argument(&self, attr: &ast::Attribute) -> Option<Symbol> {
 107         let mut value = None;
 108         for list_item in attr.meta_item_list().unwrap_or_default() {
 109             match list_item.ident() {
 110                 Some(ident) if list_item.is_word() && value.is_none() => value = Some(ident.name),
 111                 _ =>
 112                 // FIXME better-encapsulate meta_item (don't directly access `node`)
 113                 {
 114                     span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item)
 115                 }
 116             }
 117         }
 118         value
 119     }
 120
 121     fn process_attrs(&mut self, hir_id: hir::HirId) {
 122         let def_id = self.tcx.hir().local_def_id(hir_id);
 123         let def_path_hash = self.tcx.def_path_hash(def_id.to_def_id());
 124         let attrs = self.tcx.hir().attrs(hir_id);
 125         for attr in attrs {
 126             if self.tcx.sess.check_name(attr, sym::rustc_if_this_changed) {
 127                 let dep_node_interned = self.argument(attr);
 128                 let dep_node = match dep_node_interned {
 129                     None => DepNode::from_def_path_hash(def_path_hash, DepKind::hir_owner),
 130                     Some(n) => match DepNode::from_label_string(&n.as_str(), def_path_hash) {
 131                         Ok(n) => n,
 132                         Err(()) => {
 133                             self.tcx.sess.span_fatal(
 134                                 attr.span,
 135                                 &format!("unrecognized DepNode variant {:?}", n),
 136                             );
 137                         }
 138                     },
 139                 };
 140                 self.if_this_changed.push((attr.span, def_id.to_def_id(), dep_node));
 141             } else if self.tcx.sess.check_name(attr, sym::rustc_then_this_would_need) {
 142                 let dep_node_interned = self.argument(attr);
 143                 let dep_node = match dep_node_interned {
 144                     Some(n) => match DepNode::from_label_string(&n.as_str(), def_path_hash) {
 145                         Ok(n) => n,
 146                         Err(()) => {
 147                             self.tcx.sess.span_fatal(
 148                                 attr.span,
 149                                 &format!("unrecognized DepNode variant {:?}", n),
 150                             );
 151                         }
 152                     },
 153                     None => {
 154                         self.tcx.sess.span_fatal(attr.span, "missing DepNode variant");
 155                     }
 156                 };
 157                 self.then_this_would_need.push((
 158                     attr.span,
 159                     dep_node_interned.unwrap(),
 160                     hir_id,
 161                     dep_node,
 162                 ));
 163             }
 164         }
 165     }
 166 }
 167
 168 impl Visitor<'tcx> for IfThisChanged<'tcx> {
 169     type Map = Map<'tcx>;
 170
 171     fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
 172         NestedVisitorMap::OnlyBodies(self.tcx.hir())
 173     }
 174
 175     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
 176         self.process_attrs(item.hir_id());
 177         intravisit::walk_item(self, item);
 178     }
 179
 180     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
 181         self.process_attrs(trait_item.hir_id());
 182         intravisit::walk_trait_item(self, trait_item);
 183     }
 184
 185     fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
 186         self.process_attrs(impl_item.hir_id());
 187         intravisit::walk_impl_item(self, impl_item);
 188     }
 189
 190     fn visit_field_def(&mut self, s: &'tcx hir::FieldDef<'tcx>) {
 191         self.process_attrs(s.hir_id);
 192         intravisit::walk_field_def(self, s);
 193     }
 194 }
 195
 196 fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_would_need: &Targets) {
 197     // Return early here so as not to construct the query, which is not cheap.
 198     if if_this_changed.is_empty() {
 199         for &(target_span, _, _, _) in then_this_would_need {
 200             tcx.sess.span_err(target_span, "no `#[rustc_if_this_changed]` annotation detected");
 201         }
 202         return;
 203     }
 204     tcx.dep_graph.with_query(|query| {
 205         for &(_, source_def_id, ref source_dep_node) in if_this_changed {
 206             let dependents = query.transitive_predecessors(source_dep_node);
 207             for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
 208                 if !dependents.contains(&target_dep_node) {
 209                     tcx.sess.span_err(
 210                         target_span,
 211                         &format!(
 212                             "no path from `{}` to `{}`",
 213                             tcx.def_path_str(source_def_id),
 214                             target_pass
 215                         ),
 216                     );
 217                 } else {
 218                     tcx.sess.span_err(target_span, "OK");
 219                 }
 220             }
 221         }
 222     });
 223 }
 224
 225 fn dump_graph(query: &DepGraphQuery) {
 226     let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
 227
 228     let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
 229         Ok(string) => {
 230             // Expect one of: "-> target", "source -> target", or "source ->".
 231             let edge_filter =
 232                 EdgeFilter::new(&string).unwrap_or_else(|e| bug!("invalid filter: {}", e));
 233             let sources = node_set(&query, &edge_filter.source);
 234             let targets = node_set(&query, &edge_filter.target);
 235             filter_nodes(&query, &sources, &targets)
 236         }
 237         Err(_) => query.nodes().into_iter().collect(),
 238     };
 239     let edges = filter_edges(&query, &nodes);
 240
 241     {
 242         // dump a .txt file with just the edges:
 243         let txt_path = format!("{}.txt", path);
 244         let mut file = BufWriter::new(File::create(&txt_path).unwrap());
 245         for &(ref source, ref target) in &edges {
 246             write!(file, "{:?} -> {:?}\n", source, target).unwrap();
 247         }
 248     }
 249
 250     {
 251         // dump a .dot file in graphviz format:
 252         let dot_path = format!("{}.dot", path);
 253         let mut v = Vec::new();
 254         dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
 255         fs::write(dot_path, v).unwrap();
 256     }
 257 }
 258
 259 pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>, Vec<(&'q DepNode, &'q DepNode)>);
 260
 261 impl<'a, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
 262     type Node = &'q DepNode;
 263     type Edge = (&'q DepNode, &'q DepNode);
 264     fn nodes(&self) -> dot::Nodes<'_, &'q DepNode> {
 265         let nodes: Vec<_> = self.0.iter().cloned().collect();
 266         nodes.into()
 267     }
 268     fn edges(&self) -> dot::Edges<'_, (&'q DepNode, &'q DepNode)> {
 269         self.1[..].into()
 270     }
 271     fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
 272         edge.0
 273     }
 274     fn target(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
 275         edge.1
 276     }
 277 }
 278
 279 impl<'a, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
 280     type Node = &'q DepNode;
 281     type Edge = (&'q DepNode, &'q DepNode);
 282     fn graph_id(&self) -> dot::Id<'_> {
 283         dot::Id::new("DependencyGraph").unwrap()
 284     }
 285     fn node_id(&self, n: &&'q DepNode) -> dot::Id<'_> {
 286         let s: String = format!("{:?}", n)
 287             .chars()
 288             .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
 289             .collect();
 290         debug!("n={:?} s={:?}", n, s);
 291         dot::Id::new(s).unwrap()
 292     }
 293     fn node_label(&self, n: &&'q DepNode) -> dot::LabelText<'_> {
 294         dot::LabelText::label(format!("{:?}", n))
 295     }
 296 }
 297
 298 // Given an optional filter like `"x,y,z"`, returns either `None` (no
 299 // filter) or the set of nodes whose labels contain all of those
 300 // substrings.
 301 fn node_set<'q>(
 302     query: &'q DepGraphQuery,
 303     filter: &DepNodeFilter,
 304 ) -> Option<FxHashSet<&'q DepNode>> {
 305     debug!("node_set(filter={:?})", filter);
 306
 307     if filter.accepts_all() {
 308         return None;
 309     }
 310
 311     Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
 312 }
 313
 314 fn filter_nodes<'q>(
 315     query: &'q DepGraphQuery,
 316     sources: &Option<FxHashSet<&'q DepNode>>,
 317     targets: &Option<FxHashSet<&'q DepNode>>,
 318 ) -> FxHashSet<&'q DepNode> {
 319     if let Some(sources) = sources {
 320         if let Some(targets) = targets {
 321             walk_between(query, sources, targets)
 322         } else {
 323             walk_nodes(query, sources, OUTGOING)
 324         }
 325     } else if let Some(targets) = targets {
 326         walk_nodes(query, targets, INCOMING)
 327     } else {
 328         query.nodes().into_iter().collect()
 329     }
 330 }
 331
 332 fn walk_nodes<'q>(
 333     query: &'q DepGraphQuery,
 334     starts: &FxHashSet<&'q DepNode>,
 335     direction: Direction,
 336 ) -> FxHashSet<&'q DepNode> {
 337     let mut set = FxHashSet::default();
 338     for &start in starts {
 339         debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
 340         if set.insert(start) {
 341             let mut stack = vec![query.indices[start]];
 342             while let Some(index) = stack.pop() {
 343                 for (_, edge) in query.graph.adjacent_edges(index, direction) {
 344                     let neighbor_index = edge.source_or_target(direction);
 345                     let neighbor = query.graph.node_data(neighbor_index);
 346                     if set.insert(neighbor) {
 347                         stack.push(neighbor_index);
 348                     }
 349                 }
 350             }
 351         }
 352     }
 353     set
 354 }
 355
 356 fn walk_between<'q>(
 357     query: &'q DepGraphQuery,
 358     sources: &FxHashSet<&'q DepNode>,
 359     targets: &FxHashSet<&'q DepNode>,
 360 ) -> FxHashSet<&'q DepNode> {
 361     // This is a bit tricky. We want to include a node only if it is:
 362     // (a) reachable from a source and (b) will reach a target. And we
 363     // have to be careful about cycles etc.  Luckily efficiency is not
 364     // a big concern!
 365
 366     #[derive(Copy, Clone, PartialEq)]
 367     enum State {
 368         Undecided,
 369         Deciding,
 370         Included,
 371         Excluded,
 372     }
 373
 374     let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
 375
 376     for &target in targets {
 377         node_states[query.indices[target].0] = State::Included;
 378     }
 379
 380     for source in sources.iter().map(|&n| query.indices[n]) {
 381         recurse(query, &mut node_states, source);
 382     }
 383
 384     return query
 385         .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, node_states: &mut [State], node: NodeIndex) -> bool {
 394         match node_states[node.0] {
 395             // known to reach a target
 396             State::Included => return true,
 397
 398             // known not to reach a target
 399             State::Excluded => return false,
 400
 401             // backedge, not yet known, say false
 402             State::Deciding => return false,
 403
 404             State::Undecided => {}
 405         }
 406
 407         node_states[node.0] = State::Deciding;
 408
 409         for neighbor_index in query.graph.successor_nodes(node) {
 410             if recurse(query, node_states, neighbor_index) {
 411                 node_states[node.0] = State::Included;
 412             }
 413         }
 414
 415         // if we didn't find a path to target, then set to excluded
 416         if node_states[node.0] == State::Deciding {
 417             node_states[node.0] = State::Excluded;
 418             false
 419         } else {
 420             assert!(node_states[node.0] == State::Included);
 421             true
 422         }
 423     }
 424 }
 425
 426 fn filter_edges<'q>(
 427     query: &'q DepGraphQuery,
 428     nodes: &FxHashSet<&'q DepNode>,
 429 ) -> Vec<(&'q DepNode, &'q DepNode)> {
 430     query
 431         .edges()
 432         .into_iter()
 433         .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))
 434         .collect()
 435 }