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::{DepGraphQuery, DepNode, DepKind};
38 use rustc::dep_graph::debug::{DepNodeFilter, EdgeFilter};
39 use rustc::hir::def_id::DefId;
40 use rustc::ty::TyCtxt;
41 use rustc_data_structures::fx::FxHashSet;
42 use rustc_data_structures::graph::implementation::{
43 Direction, INCOMING, OUTGOING, NodeIndex
46 use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
47 use rustc::ich::{ATTR_IF_THIS_CHANGED, ATTR_THEN_THIS_WOULD_NEED};
49 use std::fs::{self, File};
54 pub fn assert_dep_graph(tcx: TyCtxt<'_>) {
55 tcx.dep_graph.with_ignore(|| {
56 if tcx.sess.opts.debugging_opts.dump_dep_graph {
60 // if the `rustc_attrs` feature is not enabled, then the
61 // attributes we are interested in cannot be present anyway, so
63 if !tcx.features().rustc_attrs {
67 // Find annotations supplied by user (if any).
68 let (if_this_changed, then_this_would_need) = {
69 let mut visitor = IfThisChanged { tcx,
70 if_this_changed: vec![],
71 then_this_would_need: vec![] };
72 visitor.process_attrs(hir::CRATE_HIR_ID, &tcx.hir().krate().attrs);
73 tcx.hir().krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
74 (visitor.if_this_changed, visitor.then_this_would_need)
77 if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
78 assert!(tcx.sess.opts.debugging_opts.query_dep_graph,
79 "cannot use the `#[{}]` or `#[{}]` annotations \
80 without supplying `-Z query-dep-graph`",
81 ATTR_IF_THIS_CHANGED, ATTR_THEN_THIS_WOULD_NEED);
85 check_paths(tcx, &if_this_changed, &then_this_would_need);
89 type Sources = Vec<(Span, DefId, DepNode)>;
90 type Targets = Vec<(Span, ast::Name, hir::HirId, DepNode)>;
92 struct IfThisChanged<'tcx> {
94 if_this_changed: Sources,
95 then_this_would_need: Targets,
98 impl IfThisChanged<'tcx> {
99 fn argument(&self, attr: &ast::Attribute) -> Option<ast::Name> {
100 let mut value = None;
101 for list_item in attr.meta_item_list().unwrap_or_default() {
102 match list_item.ident() {
103 Some(ident) if list_item.is_word() && value.is_none() =>
104 value = Some(ident.name),
106 // FIXME better-encapsulate meta_item (don't directly access `node`)
107 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(ATTR_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),
122 match DepNode::from_label_string(&n.as_str(), def_path_hash) {
125 self.tcx.sess.span_fatal(
127 &format!("unrecognized DepNode variant {:?}", n));
132 self.if_this_changed.push((attr.span, def_id, dep_node));
133 } else if attr.check_name(ATTR_THEN_THIS_WOULD_NEED) {
134 let dep_node_interned = self.argument(attr);
135 let dep_node = match dep_node_interned {
137 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(
149 "missing DepNode variant");
152 self.then_this_would_need.push((attr.span,
153 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) {
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) {
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) {
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) {
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 {
193 "no `#[rustc_if_this_changed]` annotation detected");
198 let query = tcx.dep_graph.query();
199 for &(_, source_def_id, ref source_dep_node) in if_this_changed {
200 let dependents = query.transitive_predecessors(source_dep_node);
201 for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
202 if !dependents.contains(&target_dep_node) {
205 &format!("no path from `{}` to `{}`",
206 tcx.def_path_str(source_def_id),
217 fn dump_graph(tcx: TyCtxt<'_>) {
218 let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
219 let query = tcx.dep_graph.query();
221 let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
223 // Expect one of: "-> target", "source -> target", or "source ->".
224 let edge_filter = EdgeFilter::new(&string).unwrap_or_else(|e| {
225 bug!("invalid filter: {}", e)
227 let sources = node_set(&query, &edge_filter.source);
228 let targets = node_set(&query, &edge_filter.target);
229 filter_nodes(&query, &sources, &targets)
237 let edges = filter_edges(&query, &nodes);
239 { // dump a .txt file with just the edges:
240 let txt_path = format!("{}.txt", path);
241 let mut file = File::create(&txt_path).unwrap();
242 for &(ref source, ref target) in &edges {
243 write!(file, "{:?} -> {:?}\n", source, target).unwrap();
247 { // dump a .dot file in graphviz format:
248 let dot_path = format!("{}.dot", path);
249 let mut v = Vec::new();
250 dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
251 fs::write(dot_path, v).unwrap();
255 pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>,
256 Vec<(&'q DepNode, &'q DepNode)>);
258 impl<'a, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
259 type Node = &'q DepNode;
260 type Edge = (&'q DepNode, &'q DepNode);
261 fn nodes(&self) -> dot::Nodes<'_, &'q DepNode> {
262 let nodes: Vec<_> = self.0.iter().cloned().collect();
265 fn edges(&self) -> dot::Edges<'_, (&'q DepNode, &'q DepNode)> {
268 fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
271 fn target(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
276 impl<'a, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
277 type Node = &'q DepNode;
278 type Edge = (&'q DepNode, &'q DepNode);
279 fn graph_id(&self) -> dot::Id<'_> {
280 dot::Id::new("DependencyGraph").unwrap()
282 fn node_id(&self, n: &&'q DepNode) -> dot::Id<'_> {
284 format!("{:?}", n).chars()
285 .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
287 debug!("n={:?} s={:?}", n, s);
288 dot::Id::new(s).unwrap()
290 fn node_label(&self, n: &&'q DepNode) -> dot::LabelText<'_> {
291 dot::LabelText::label(format!("{:?}", n))
295 // Given an optional filter like `"x,y,z"`, returns either `None` (no
296 // filter) or the set of nodes whose labels contain all of those
298 fn node_set<'q>(query: &'q DepGraphQuery, filter: &DepNodeFilter)
299 -> Option<FxHashSet<&'q DepNode>>
301 debug!("node_set(filter={:?})", filter);
303 if filter.accepts_all() {
307 Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
310 fn filter_nodes<'q>(query: &'q DepGraphQuery,
311 sources: &Option<FxHashSet<&'q DepNode>>,
312 targets: &Option<FxHashSet<&'q DepNode>>)
313 -> FxHashSet<&'q DepNode>
315 if let &Some(ref sources) = sources {
316 if let &Some(ref targets) = targets {
317 walk_between(query, sources, targets)
319 walk_nodes(query, sources, OUTGOING)
321 } else if let &Some(ref targets) = targets {
322 walk_nodes(query, targets, INCOMING)
324 query.nodes().into_iter().collect()
328 fn walk_nodes<'q>(query: &'q DepGraphQuery,
329 starts: &FxHashSet<&'q DepNode>,
330 direction: Direction)
331 -> FxHashSet<&'q DepNode>
333 let mut set = FxHashSet::default();
334 for &start in starts {
335 debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
336 if set.insert(start) {
337 let mut stack = vec![query.indices[start]];
338 while let Some(index) = stack.pop() {
339 for (_, edge) in query.graph.adjacent_edges(index, direction) {
340 let neighbor_index = edge.source_or_target(direction);
341 let neighbor = query.graph.node_data(neighbor_index);
342 if set.insert(neighbor) {
343 stack.push(neighbor_index);
352 fn walk_between<'q>(query: &'q DepGraphQuery,
353 sources: &FxHashSet<&'q DepNode>,
354 targets: &FxHashSet<&'q DepNode>)
355 -> FxHashSet<&'q DepNode>
357 // This is a bit tricky. We want to include a node only if it is:
358 // (a) reachable from a source and (b) will reach a target. And we
359 // have to be careful about cycles etc. Luckily efficiency is not
362 #[derive(Copy, Clone, PartialEq)]
363 enum State { Undecided, Deciding, Included, Excluded }
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);
378 let index = query.indices[n];
379 node_states[index.0] == State::Included
383 fn recurse(query: &DepGraphQuery,
384 node_states: &mut [State],
388 match node_states[node.0] {
389 // known to reach a target
390 State::Included => return true,
392 // known not to reach a target
393 State::Excluded => return false,
395 // backedge, not yet known, say false
396 State::Deciding => return false,
398 State::Undecided => { }
401 node_states[node.0] = State::Deciding;
403 for neighbor_index in query.graph.successor_nodes(node) {
404 if recurse(query, node_states, neighbor_index) {
405 node_states[node.0] = State::Included;
409 // if we didn't find a path to target, then set to excluded
410 if node_states[node.0] == State::Deciding {
411 node_states[node.0] = State::Excluded;
414 assert!(node_states[node.0] == State::Included);
420 fn filter_edges<'q>(query: &'q DepGraphQuery,
421 nodes: &FxHashSet<&'q DepNode>)
422 -> Vec<(&'q DepNode, &'q DepNode)>
426 .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))