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
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. `compile-fail` tests can then be
16 //! used to check when paths exist or do not.
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.
26 //! #[rustc_if_this_changed(Hir)]
29 //! #[rustc_then_this_would_need(codegen)] //~ ERROR no path from `foo`
32 //! #[rustc_then_this_would_need(codegen)] //~ ERROR OK
33 //! fn baz() { foo(); }
37 use rustc::dep_graph::debug::{DepNodeFilter, EdgeFilter};
38 use rustc::dep_graph::{DepGraphQuery, DepKind, DepNode};
40 use rustc::hir::def_id::DefId;
41 use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
42 use rustc::ty::TyCtxt;
43 use rustc_data_structures::fx::FxHashSet;
44 use rustc_data_structures::graph::implementation::{Direction, NodeIndex, INCOMING, OUTGOING};
47 use std::fs::{self, File};
49 use syntax::{ast, symbol::sym};
51 pub fn assert_dep_graph(tcx: TyCtxt<'_>) {
52 tcx.dep_graph.with_ignore(|| {
53 if tcx.sess.opts.debugging_opts.dump_dep_graph {
57 // if the `rustc_attrs` feature is not enabled, then the
58 // attributes we are interested in cannot be present anyway, so
60 if !tcx.features().rustc_attrs {
64 // Find annotations supplied by user (if any).
65 let (if_this_changed, then_this_would_need) = {
67 IfThisChanged { tcx, if_this_changed: vec![], then_this_would_need: vec![] };
68 visitor.process_attrs(hir::CRATE_HIR_ID, &tcx.hir().krate().attrs);
69 tcx.hir().krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
70 (visitor.if_this_changed, visitor.then_this_would_need)
73 if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
75 tcx.sess.opts.debugging_opts.query_dep_graph,
76 "cannot use the `#[{}]` or `#[{}]` annotations \
77 without supplying `-Z query-dep-graph`",
78 sym::rustc_if_this_changed,
79 sym::rustc_then_this_would_need
84 check_paths(tcx, &if_this_changed, &then_this_would_need);
88 type Sources = Vec<(Span, DefId, DepNode)>;
89 type Targets = Vec<(Span, ast::Name, hir::HirId, DepNode)>;
91 struct IfThisChanged<'tcx> {
93 if_this_changed: Sources,
94 then_this_would_need: Targets,
97 impl IfThisChanged<'tcx> {
98 fn argument(&self, attr: &ast::Attribute) -> Option<ast::Name> {
100 for list_item in attr.meta_item_list().unwrap_or_default() {
101 match list_item.ident() {
102 Some(ident) if list_item.is_word() && value.is_none() => value = Some(ident.name),
104 // FIXME better-encapsulate meta_item (don't directly access `node`)
106 span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item)
113 fn process_attrs(&mut self, hir_id: hir::HirId, attrs: &[ast::Attribute]) {
114 let def_id = self.tcx.hir().local_def_id(hir_id);
115 let def_path_hash = self.tcx.def_path_hash(def_id);
117 if attr.check_name(sym::rustc_if_this_changed) {
118 let dep_node_interned = self.argument(attr);
119 let dep_node = match dep_node_interned {
120 None => def_path_hash.to_dep_node(DepKind::Hir),
121 Some(n) => match DepNode::from_label_string(&n.as_str(), def_path_hash) {
124 self.tcx.sess.span_fatal(
126 &format!("unrecognized DepNode variant {:?}", n),
131 self.if_this_changed.push((attr.span, def_id, dep_node));
132 } else if attr.check_name(sym::rustc_then_this_would_need) {
133 let dep_node_interned = self.argument(attr);
134 let dep_node = match dep_node_interned {
135 Some(n) => match DepNode::from_label_string(&n.as_str(), def_path_hash) {
138 self.tcx.sess.span_fatal(
140 &format!("unrecognized DepNode variant {:?}", n),
145 self.tcx.sess.span_fatal(attr.span, "missing DepNode variant");
148 self.then_this_would_need.push((
150 dep_node_interned.unwrap(),
159 impl Visitor<'tcx> for IfThisChanged<'tcx> {
160 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
161 NestedVisitorMap::OnlyBodies(&self.tcx.hir())
164 fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
165 self.process_attrs(item.hir_id, &item.attrs);
166 intravisit::walk_item(self, item);
169 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
170 self.process_attrs(trait_item.hir_id, &trait_item.attrs);
171 intravisit::walk_trait_item(self, trait_item);
174 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
175 self.process_attrs(impl_item.hir_id, &impl_item.attrs);
176 intravisit::walk_impl_item(self, impl_item);
179 fn visit_struct_field(&mut self, s: &'tcx hir::StructField<'tcx>) {
180 self.process_attrs(s.hir_id, &s.attrs);
181 intravisit::walk_struct_field(self, s);
185 fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_would_need: &Targets) {
186 // Return early here so as not to construct the query, which is not cheap.
187 if if_this_changed.is_empty() {
188 for &(target_span, _, _, _) in then_this_would_need {
189 tcx.sess.span_err(target_span, "no `#[rustc_if_this_changed]` annotation detected");
193 let query = tcx.dep_graph.query();
194 for &(_, source_def_id, ref source_dep_node) in if_this_changed {
195 let dependents = query.transitive_predecessors(source_dep_node);
196 for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
197 if !dependents.contains(&target_dep_node) {
201 "no path from `{}` to `{}`",
202 tcx.def_path_str(source_def_id),
207 tcx.sess.span_err(target_span, "OK");
213 fn dump_graph(tcx: TyCtxt<'_>) {
214 let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
215 let query = tcx.dep_graph.query();
217 let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
219 // Expect one of: "-> target", "source -> target", or "source ->".
221 EdgeFilter::new(&string).unwrap_or_else(|e| bug!("invalid filter: {}", e));
222 let sources = node_set(&query, &edge_filter.source);
223 let targets = node_set(&query, &edge_filter.target);
224 filter_nodes(&query, &sources, &targets)
226 Err(_) => query.nodes().into_iter().collect(),
228 let edges = filter_edges(&query, &nodes);
231 // dump a .txt file with just the edges:
232 let txt_path = format!("{}.txt", path);
233 let mut file = File::create(&txt_path).unwrap();
234 for &(ref source, ref target) in &edges {
235 write!(file, "{:?} -> {:?}\n", source, target).unwrap();
240 // dump a .dot file in graphviz format:
241 let dot_path = format!("{}.dot", path);
242 let mut v = Vec::new();
243 dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
244 fs::write(dot_path, v).unwrap();
248 pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>, Vec<(&'q DepNode, &'q DepNode)>);
250 impl<'a, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
251 type Node = &'q DepNode;
252 type Edge = (&'q DepNode, &'q DepNode);
253 fn nodes(&self) -> dot::Nodes<'_, &'q DepNode> {
254 let nodes: Vec<_> = self.0.iter().cloned().collect();
257 fn edges(&self) -> dot::Edges<'_, (&'q DepNode, &'q DepNode)> {
260 fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
263 fn target(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
268 impl<'a, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
269 type Node = &'q DepNode;
270 type Edge = (&'q DepNode, &'q DepNode);
271 fn graph_id(&self) -> dot::Id<'_> {
272 dot::Id::new("DependencyGraph").unwrap()
274 fn node_id(&self, n: &&'q DepNode) -> dot::Id<'_> {
275 let s: String = format!("{:?}", n)
277 .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
279 debug!("n={:?} s={:?}", n, s);
280 dot::Id::new(s).unwrap()
282 fn node_label(&self, n: &&'q DepNode) -> dot::LabelText<'_> {
283 dot::LabelText::label(format!("{:?}", n))
287 // Given an optional filter like `"x,y,z"`, returns either `None` (no
288 // filter) or the set of nodes whose labels contain all of those
291 query: &'q DepGraphQuery,
292 filter: &DepNodeFilter,
293 ) -> Option<FxHashSet<&'q DepNode>> {
294 debug!("node_set(filter={:?})", filter);
296 if filter.accepts_all() {
300 Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
304 query: &'q DepGraphQuery,
305 sources: &Option<FxHashSet<&'q DepNode>>,
306 targets: &Option<FxHashSet<&'q DepNode>>,
307 ) -> FxHashSet<&'q DepNode> {
308 if let &Some(ref sources) = sources {
309 if let &Some(ref targets) = targets {
310 walk_between(query, sources, targets)
312 walk_nodes(query, sources, OUTGOING)
314 } else if let &Some(ref targets) = targets {
315 walk_nodes(query, targets, INCOMING)
317 query.nodes().into_iter().collect()
322 query: &'q DepGraphQuery,
323 starts: &FxHashSet<&'q DepNode>,
324 direction: Direction,
325 ) -> FxHashSet<&'q DepNode> {
326 let mut set = FxHashSet::default();
327 for &start in starts {
328 debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
329 if set.insert(start) {
330 let mut stack = vec![query.indices[start]];
331 while let Some(index) = stack.pop() {
332 for (_, edge) in query.graph.adjacent_edges(index, direction) {
333 let neighbor_index = edge.source_or_target(direction);
334 let neighbor = query.graph.node_data(neighbor_index);
335 if set.insert(neighbor) {
336 stack.push(neighbor_index);
346 query: &'q DepGraphQuery,
347 sources: &FxHashSet<&'q DepNode>,
348 targets: &FxHashSet<&'q DepNode>,
349 ) -> FxHashSet<&'q DepNode> {
350 // This is a bit tricky. We want to include a node only if it is:
351 // (a) reachable from a source and (b) will reach a target. And we
352 // have to be careful about cycles etc. Luckily efficiency is not
355 #[derive(Copy, Clone, PartialEq)]
363 let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
365 for &target in targets {
366 node_states[query.indices[target].0] = State::Included;
369 for source in sources.iter().map(|&n| query.indices[n]) {
370 recurse(query, &mut node_states, source);
377 let index = query.indices[n];
378 node_states[index.0] == State::Included
382 fn recurse(query: &DepGraphQuery, node_states: &mut [State], node: NodeIndex) -> bool {
383 match node_states[node.0] {
384 // known to reach a target
385 State::Included => return true,
387 // known not to reach a target
388 State::Excluded => return false,
390 // backedge, not yet known, say false
391 State::Deciding => return false,
393 State::Undecided => {}
396 node_states[node.0] = State::Deciding;
398 for neighbor_index in query.graph.successor_nodes(node) {
399 if recurse(query, node_states, neighbor_index) {
400 node_states[node.0] = State::Included;
404 // if we didn't find a path to target, then set to excluded
405 if node_states[node.0] == State::Deciding {
406 node_states[node.0] = State::Excluded;
409 assert!(node_states[node.0] == State::Included);
416 query: &'q DepGraphQuery,
417 nodes: &FxHashSet<&'q DepNode>,
418 ) -> Vec<(&'q DepNode, &'q DepNode)> {
422 .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))