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};
39 use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
40 use rustc::ty::TyCtxt;
41 use rustc_data_structures::fx::FxHashSet;
42 use rustc_data_structures::graph::implementation::{Direction, NodeIndex, INCOMING, OUTGOING};
44 use rustc_hir::def_id::DefId;
45 use rustc_span::symbol::sym;
50 use std::fs::{self, File};
53 pub fn assert_dep_graph(tcx: TyCtxt<'_>) {
54 tcx.dep_graph.with_ignore(|| {
55 if tcx.sess.opts.debugging_opts.dump_dep_graph {
59 // if the `rustc_attrs` feature is not enabled, then the
60 // attributes we are interested in cannot be present anyway, so
62 if !tcx.features().rustc_attrs {
66 // Find annotations supplied by user (if any).
67 let (if_this_changed, then_this_would_need) = {
69 IfThisChanged { tcx, if_this_changed: vec![], then_this_would_need: vec![] };
70 visitor.process_attrs(hir::CRATE_HIR_ID, &tcx.hir().krate().attrs);
71 tcx.hir().krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
72 (visitor.if_this_changed, visitor.then_this_would_need)
75 if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
77 tcx.sess.opts.debugging_opts.query_dep_graph,
78 "cannot use the `#[{}]` or `#[{}]` annotations \
79 without supplying `-Z query-dep-graph`",
80 sym::rustc_if_this_changed,
81 sym::rustc_then_this_would_need
86 check_paths(tcx, &if_this_changed, &then_this_would_need);
90 type Sources = Vec<(Span, DefId, DepNode)>;
91 type Targets = Vec<(Span, ast::Name, hir::HirId, DepNode)>;
93 struct IfThisChanged<'tcx> {
95 if_this_changed: Sources,
96 then_this_would_need: Targets,
99 impl IfThisChanged<'tcx> {
100 fn argument(&self, attr: &ast::Attribute) -> Option<ast::Name> {
101 let mut value = None;
102 for list_item in attr.meta_item_list().unwrap_or_default() {
103 match list_item.ident() {
104 Some(ident) if list_item.is_word() && value.is_none() => value = Some(ident.name),
106 // FIXME better-encapsulate meta_item (don't directly access `node`)
108 span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item)
115 fn process_attrs(&mut self, hir_id: hir::HirId, attrs: &[ast::Attribute]) {
116 let def_id = self.tcx.hir().local_def_id(hir_id);
117 let def_path_hash = self.tcx.def_path_hash(def_id);
119 if attr.check_name(sym::rustc_if_this_changed) {
120 let dep_node_interned = self.argument(attr);
121 let dep_node = match dep_node_interned {
122 None => def_path_hash.to_dep_node(DepKind::Hir),
123 Some(n) => match DepNode::from_label_string(&n.as_str(), def_path_hash) {
126 self.tcx.sess.span_fatal(
128 &format!("unrecognized DepNode variant {:?}", n),
133 self.if_this_changed.push((attr.span, def_id, dep_node));
134 } else if attr.check_name(sym::rustc_then_this_would_need) {
135 let dep_node_interned = self.argument(attr);
136 let dep_node = match dep_node_interned {
137 Some(n) => match DepNode::from_label_string(&n.as_str(), def_path_hash) {
140 self.tcx.sess.span_fatal(
142 &format!("unrecognized DepNode variant {:?}", n),
147 self.tcx.sess.span_fatal(attr.span, "missing DepNode variant");
150 self.then_this_would_need.push((
152 dep_node_interned.unwrap(),
161 impl Visitor<'tcx> for IfThisChanged<'tcx> {
162 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
163 NestedVisitorMap::OnlyBodies(&self.tcx.hir())
166 fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
167 self.process_attrs(item.hir_id, &item.attrs);
168 intravisit::walk_item(self, item);
171 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
172 self.process_attrs(trait_item.hir_id, &trait_item.attrs);
173 intravisit::walk_trait_item(self, trait_item);
176 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
177 self.process_attrs(impl_item.hir_id, &impl_item.attrs);
178 intravisit::walk_impl_item(self, impl_item);
181 fn visit_struct_field(&mut self, s: &'tcx hir::StructField<'tcx>) {
182 self.process_attrs(s.hir_id, &s.attrs);
183 intravisit::walk_struct_field(self, s);
187 fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_would_need: &Targets) {
188 // Return early here so as not to construct the query, which is not cheap.
189 if if_this_changed.is_empty() {
190 for &(target_span, _, _, _) in then_this_would_need {
191 tcx.sess.span_err(target_span, "no `#[rustc_if_this_changed]` annotation detected");
195 let query = tcx.dep_graph.query();
196 for &(_, source_def_id, ref source_dep_node) in if_this_changed {
197 let dependents = query.transitive_predecessors(source_dep_node);
198 for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
199 if !dependents.contains(&target_dep_node) {
203 "no path from `{}` to `{}`",
204 tcx.def_path_str(source_def_id),
209 tcx.sess.span_err(target_span, "OK");
215 fn dump_graph(tcx: TyCtxt<'_>) {
216 let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
217 let query = tcx.dep_graph.query();
219 let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
221 // Expect one of: "-> target", "source -> target", or "source ->".
223 EdgeFilter::new(&string).unwrap_or_else(|e| bug!("invalid filter: {}", e));
224 let sources = node_set(&query, &edge_filter.source);
225 let targets = node_set(&query, &edge_filter.target);
226 filter_nodes(&query, &sources, &targets)
228 Err(_) => query.nodes().into_iter().collect(),
230 let edges = filter_edges(&query, &nodes);
233 // dump a .txt file with just the edges:
234 let txt_path = format!("{}.txt", path);
235 let mut file = File::create(&txt_path).unwrap();
236 for &(ref source, ref target) in &edges {
237 write!(file, "{:?} -> {:?}\n", source, target).unwrap();
242 // dump a .dot file in graphviz format:
243 let dot_path = format!("{}.dot", path);
244 let mut v = Vec::new();
245 dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
246 fs::write(dot_path, v).unwrap();
250 pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>, Vec<(&'q DepNode, &'q DepNode)>);
252 impl<'a, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
253 type Node = &'q DepNode;
254 type Edge = (&'q DepNode, &'q DepNode);
255 fn nodes(&self) -> dot::Nodes<'_, &'q DepNode> {
256 let nodes: Vec<_> = self.0.iter().cloned().collect();
259 fn edges(&self) -> dot::Edges<'_, (&'q DepNode, &'q DepNode)> {
262 fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
265 fn target(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
270 impl<'a, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
271 type Node = &'q DepNode;
272 type Edge = (&'q DepNode, &'q DepNode);
273 fn graph_id(&self) -> dot::Id<'_> {
274 dot::Id::new("DependencyGraph").unwrap()
276 fn node_id(&self, n: &&'q DepNode) -> dot::Id<'_> {
277 let s: String = format!("{:?}", n)
279 .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
281 debug!("n={:?} s={:?}", n, s);
282 dot::Id::new(s).unwrap()
284 fn node_label(&self, n: &&'q DepNode) -> dot::LabelText<'_> {
285 dot::LabelText::label(format!("{:?}", n))
289 // Given an optional filter like `"x,y,z"`, returns either `None` (no
290 // filter) or the set of nodes whose labels contain all of those
293 query: &'q DepGraphQuery,
294 filter: &DepNodeFilter,
295 ) -> Option<FxHashSet<&'q DepNode>> {
296 debug!("node_set(filter={:?})", filter);
298 if filter.accepts_all() {
302 Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
306 query: &'q DepGraphQuery,
307 sources: &Option<FxHashSet<&'q DepNode>>,
308 targets: &Option<FxHashSet<&'q DepNode>>,
309 ) -> FxHashSet<&'q DepNode> {
310 if let &Some(ref sources) = sources {
311 if let &Some(ref targets) = targets {
312 walk_between(query, sources, targets)
314 walk_nodes(query, sources, OUTGOING)
316 } else if let &Some(ref targets) = targets {
317 walk_nodes(query, targets, INCOMING)
319 query.nodes().into_iter().collect()
324 query: &'q DepGraphQuery,
325 starts: &FxHashSet<&'q DepNode>,
326 direction: Direction,
327 ) -> FxHashSet<&'q DepNode> {
328 let mut set = FxHashSet::default();
329 for &start in starts {
330 debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
331 if set.insert(start) {
332 let mut stack = vec![query.indices[start]];
333 while let Some(index) = stack.pop() {
334 for (_, edge) in query.graph.adjacent_edges(index, direction) {
335 let neighbor_index = edge.source_or_target(direction);
336 let neighbor = query.graph.node_data(neighbor_index);
337 if set.insert(neighbor) {
338 stack.push(neighbor_index);
348 query: &'q DepGraphQuery,
349 sources: &FxHashSet<&'q DepNode>,
350 targets: &FxHashSet<&'q DepNode>,
351 ) -> FxHashSet<&'q DepNode> {
352 // This is a bit tricky. We want to include a node only if it is:
353 // (a) reachable from a source and (b) will reach a target. And we
354 // have to be careful about cycles etc. Luckily efficiency is not
357 #[derive(Copy, Clone, PartialEq)]
365 let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
367 for &target in targets {
368 node_states[query.indices[target].0] = State::Included;
371 for source in sources.iter().map(|&n| query.indices[n]) {
372 recurse(query, &mut node_states, source);
379 let index = query.indices[n];
380 node_states[index.0] == State::Included
384 fn recurse(query: &DepGraphQuery, node_states: &mut [State], node: NodeIndex) -> bool {
385 match node_states[node.0] {
386 // known to reach a target
387 State::Included => return true,
389 // known not to reach a target
390 State::Excluded => return false,
392 // backedge, not yet known, say false
393 State::Deciding => return false,
395 State::Undecided => {}
398 node_states[node.0] = State::Deciding;
400 for neighbor_index in query.graph.successor_nodes(node) {
401 if recurse(query, node_states, neighbor_index) {
402 node_states[node.0] = State::Included;
406 // if we didn't find a path to target, then set to excluded
407 if node_states[node.0] == State::Deciding {
408 node_states[node.0] = State::Excluded;
411 assert!(node_states[node.0] == State::Included);
418 query: &'q DepGraphQuery,
419 nodes: &FxHashSet<&'q DepNode>,
420 ) -> Vec<(&'q DepNode, &'q DepNode)> {
424 .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))