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};
48 use std::fs::{self, File};
50 use syntax::{ast, symbol::sym};
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) = {
68 let mut visitor = IfThisChanged { tcx,
69 if_this_changed: vec![],
70 then_this_would_need: vec![] };
71 visitor.process_attrs(hir::CRATE_HIR_ID, &tcx.hir().krate().attrs);
72 tcx.hir().krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
73 (visitor.if_this_changed, visitor.then_this_would_need)
76 if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
77 assert!(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, 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() =>
103 value = Some(ident.name),
105 // FIXME better-encapsulate meta_item (don't directly access `node`)
106 span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item),
112 fn process_attrs(&mut self, hir_id: hir::HirId, attrs: &[ast::Attribute]) {
113 let def_id = self.tcx.hir().local_def_id(hir_id);
114 let def_path_hash = self.tcx.def_path_hash(def_id);
116 if attr.check_name(sym::rustc_if_this_changed) {
117 let dep_node_interned = self.argument(attr);
118 let dep_node = match dep_node_interned {
119 None => def_path_hash.to_dep_node(DepKind::Hir),
121 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 {
136 match DepNode::from_label_string(&n.as_str(), def_path_hash) {
139 self.tcx.sess.span_fatal(
141 &format!("unrecognized DepNode variant {:?}", n));
146 self.tcx.sess.span_fatal(
148 "missing DepNode variant");
151 self.then_this_would_need.push((attr.span,
152 dep_node_interned.unwrap(),
160 impl Visitor<'tcx> for IfThisChanged<'tcx> {
161 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
162 NestedVisitorMap::OnlyBodies(&self.tcx.hir())
165 fn visit_item(&mut self, item: &'tcx hir::Item) {
166 self.process_attrs(item.hir_id, &item.attrs);
167 intravisit::walk_item(self, item);
170 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
171 self.process_attrs(trait_item.hir_id, &trait_item.attrs);
172 intravisit::walk_trait_item(self, trait_item);
175 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
176 self.process_attrs(impl_item.hir_id, &impl_item.attrs);
177 intravisit::walk_impl_item(self, impl_item);
180 fn visit_struct_field(&mut self, s: &'tcx hir::StructField) {
181 self.process_attrs(s.hir_id, &s.attrs);
182 intravisit::walk_struct_field(self, s);
186 fn check_paths<'tcx>(tcx: TyCtxt<'tcx>, if_this_changed: &Sources, then_this_would_need: &Targets) {
187 // Return early here so as not to construct the query, which is not cheap.
188 if if_this_changed.is_empty() {
189 for &(target_span, _, _, _) in then_this_would_need {
192 "no `#[rustc_if_this_changed]` annotation detected");
197 let query = tcx.dep_graph.query();
198 for &(_, source_def_id, ref source_dep_node) in if_this_changed {
199 let dependents = query.transitive_predecessors(source_dep_node);
200 for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
201 if !dependents.contains(&target_dep_node) {
204 &format!("no path from `{}` to `{}`",
205 tcx.def_path_str(source_def_id),
216 fn dump_graph(tcx: TyCtxt<'_>) {
217 let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
218 let query = tcx.dep_graph.query();
220 let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
222 // Expect one of: "-> target", "source -> target", or "source ->".
223 let edge_filter = EdgeFilter::new(&string).unwrap_or_else(|e| {
224 bug!("invalid filter: {}", e)
226 let sources = node_set(&query, &edge_filter.source);
227 let targets = node_set(&query, &edge_filter.target);
228 filter_nodes(&query, &sources, &targets)
236 let edges = filter_edges(&query, &nodes);
238 { // dump a .txt file with just the edges:
239 let txt_path = format!("{}.txt", path);
240 let mut file = File::create(&txt_path).unwrap();
241 for &(ref source, ref target) in &edges {
242 write!(file, "{:?} -> {:?}\n", source, target).unwrap();
246 { // dump a .dot file in graphviz format:
247 let dot_path = format!("{}.dot", path);
248 let mut v = Vec::new();
249 dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
250 fs::write(dot_path, v).unwrap();
254 pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>,
255 Vec<(&'q DepNode, &'q DepNode)>);
257 impl<'a, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
258 type Node = &'q DepNode;
259 type Edge = (&'q DepNode, &'q DepNode);
260 fn nodes(&self) -> dot::Nodes<'_, &'q DepNode> {
261 let nodes: Vec<_> = self.0.iter().cloned().collect();
264 fn edges(&self) -> dot::Edges<'_, (&'q DepNode, &'q DepNode)> {
267 fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
270 fn target(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
275 impl<'a, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
276 type Node = &'q DepNode;
277 type Edge = (&'q DepNode, &'q DepNode);
278 fn graph_id(&self) -> dot::Id<'_> {
279 dot::Id::new("DependencyGraph").unwrap()
281 fn node_id(&self, n: &&'q DepNode) -> dot::Id<'_> {
283 format!("{:?}", n).chars()
284 .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
286 debug!("n={:?} s={:?}", n, s);
287 dot::Id::new(s).unwrap()
289 fn node_label(&self, n: &&'q DepNode) -> dot::LabelText<'_> {
290 dot::LabelText::label(format!("{:?}", n))
294 // Given an optional filter like `"x,y,z"`, returns either `None` (no
295 // filter) or the set of nodes whose labels contain all of those
297 fn node_set<'q>(query: &'q DepGraphQuery, filter: &DepNodeFilter)
298 -> Option<FxHashSet<&'q DepNode>>
300 debug!("node_set(filter={:?})", filter);
302 if filter.accepts_all() {
306 Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
309 fn filter_nodes<'q>(query: &'q DepGraphQuery,
310 sources: &Option<FxHashSet<&'q DepNode>>,
311 targets: &Option<FxHashSet<&'q DepNode>>)
312 -> FxHashSet<&'q DepNode>
314 if let &Some(ref sources) = sources {
315 if let &Some(ref targets) = targets {
316 walk_between(query, sources, targets)
318 walk_nodes(query, sources, OUTGOING)
320 } else if let &Some(ref targets) = targets {
321 walk_nodes(query, targets, INCOMING)
323 query.nodes().into_iter().collect()
327 fn walk_nodes<'q>(query: &'q DepGraphQuery,
328 starts: &FxHashSet<&'q DepNode>,
329 direction: Direction)
330 -> FxHashSet<&'q DepNode>
332 let mut set = FxHashSet::default();
333 for &start in starts {
334 debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
335 if set.insert(start) {
336 let mut stack = vec![query.indices[start]];
337 while let Some(index) = stack.pop() {
338 for (_, edge) in query.graph.adjacent_edges(index, direction) {
339 let neighbor_index = edge.source_or_target(direction);
340 let neighbor = query.graph.node_data(neighbor_index);
341 if set.insert(neighbor) {
342 stack.push(neighbor_index);
351 fn walk_between<'q>(query: &'q DepGraphQuery,
352 sources: &FxHashSet<&'q DepNode>,
353 targets: &FxHashSet<&'q DepNode>)
354 -> FxHashSet<&'q DepNode>
356 // This is a bit tricky. We want to include a node only if it is:
357 // (a) reachable from a source and (b) will reach a target. And we
358 // have to be careful about cycles etc. Luckily efficiency is not
361 #[derive(Copy, Clone, PartialEq)]
362 enum State { Undecided, Deciding, Included, Excluded }
364 let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
366 for &target in targets {
367 node_states[query.indices[target].0] = State::Included;
370 for source in sources.iter().map(|&n| query.indices[n]) {
371 recurse(query, &mut node_states, source);
377 let index = query.indices[n];
378 node_states[index.0] == State::Included
382 fn recurse(query: &DepGraphQuery,
383 node_states: &mut [State],
387 match node_states[node.0] {
388 // known to reach a target
389 State::Included => return true,
391 // known not to reach a target
392 State::Excluded => return false,
394 // backedge, not yet known, say false
395 State::Deciding => return false,
397 State::Undecided => { }
400 node_states[node.0] = State::Deciding;
402 for neighbor_index in query.graph.successor_nodes(node) {
403 if recurse(query, node_states, neighbor_index) {
404 node_states[node.0] = State::Included;
408 // if we didn't find a path to target, then set to excluded
409 if node_states[node.0] == State::Deciding {
410 node_states[node.0] = State::Excluded;
413 assert!(node_states[node.0] == State::Included);
419 fn filter_edges<'q>(query: &'q DepGraphQuery,
420 nodes: &FxHashSet<&'q DepNode>)
421 -> Vec<(&'q DepNode, &'q DepNode)>
425 .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))