1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! This pass is only used for the UNIT TESTS and DEBUGGING NEEDS
12 //! around dependency graph construction. It serves two purposes; it
13 //! will dump graphs in graphviz form to disk, and it searches for
14 //! `#[rustc_if_this_changed]` and `#[rustc_then_this_would_need]`
15 //! annotations. These annotations can be used to test whether paths
16 //! exist in the graph. These checks run after codegen, so they view the
17 //! the final state of the dependency graph. Note that there are
18 //! similar assertions found in `persist::dirty_clean` which check the
19 //! **initial** state of the dependency graph, just after it has been
22 //! In this code, we report errors on each `rustc_if_this_changed`
23 //! annotation. If a path exists in all cases, then we would report
24 //! "all path(s) exist". Otherwise, we report: "no path to `foo`" for
25 //! each case where no path exists. `compile-fail` tests can then be
26 //! used to check when paths exist or do not.
28 //! The full form of the `rustc_if_this_changed` annotation is
29 //! `#[rustc_if_this_changed("foo")]`, which will report a
30 //! source node of `foo(def_id)`. The `"foo"` is optional and
31 //! defaults to `"Hir"` if omitted.
36 //! #[rustc_if_this_changed(Hir)]
39 //! #[rustc_then_this_would_need(codegen)] //~ ERROR no path from `foo`
42 //! #[rustc_then_this_would_need(codegen)] //~ ERROR OK
43 //! fn baz() { foo(); }
47 use rustc::dep_graph::{DepGraphQuery, DepNode, DepKind};
48 use rustc::dep_graph::debug::{DepNodeFilter, EdgeFilter};
49 use rustc::hir::def_id::DefId;
50 use rustc::ty::TyCtxt;
51 use rustc_data_structures::fx::FxHashSet;
52 use rustc_data_structures::graph::implementation::{
53 Direction, INCOMING, OUTGOING, NodeIndex
56 use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
57 use rustc::ich::{ATTR_IF_THIS_CHANGED, ATTR_THEN_THIS_WOULD_NEED};
59 use std::fs::{self, File};
64 pub fn assert_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
65 tcx.dep_graph.with_ignore(|| {
66 if tcx.sess.opts.debugging_opts.dump_dep_graph {
70 // if the `rustc_attrs` feature is not enabled, then the
71 // attributes we are interested in cannot be present anyway, so
73 if !tcx.features().rustc_attrs {
77 // Find annotations supplied by user (if any).
78 let (if_this_changed, then_this_would_need) = {
79 let mut visitor = IfThisChanged { tcx,
80 if_this_changed: vec![],
81 then_this_would_need: vec![] };
82 visitor.process_attrs(ast::CRATE_NODE_ID, &tcx.hir.krate().attrs);
83 tcx.hir.krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
84 (visitor.if_this_changed, visitor.then_this_would_need)
87 if !if_this_changed.is_empty() || !then_this_would_need.is_empty() {
88 assert!(tcx.sess.opts.debugging_opts.query_dep_graph,
89 "cannot use the `#[{}]` or `#[{}]` annotations \
90 without supplying `-Z query-dep-graph`",
91 ATTR_IF_THIS_CHANGED, ATTR_THEN_THIS_WOULD_NEED);
95 check_paths(tcx, &if_this_changed, &then_this_would_need);
99 type Sources = Vec<(Span, DefId, DepNode)>;
100 type Targets = Vec<(Span, ast::Name, ast::NodeId, DepNode)>;
102 struct IfThisChanged<'a, 'tcx:'a> {
103 tcx: TyCtxt<'a, 'tcx, 'tcx>,
104 if_this_changed: Sources,
105 then_this_would_need: Targets,
108 impl<'a, 'tcx> IfThisChanged<'a, 'tcx> {
109 fn argument(&self, attr: &ast::Attribute) -> Option<ast::Name> {
110 let mut value = None;
111 for list_item in attr.meta_item_list().unwrap_or_default() {
112 match list_item.word() {
113 Some(word) if value.is_none() =>
114 value = Some(word.name()),
116 // FIXME better-encapsulate meta_item (don't directly access `node`)
117 span_bug!(list_item.span(), "unexpected meta-item {:?}", list_item.node),
123 fn process_attrs(&mut self, node_id: ast::NodeId, attrs: &[ast::Attribute]) {
124 let def_id = self.tcx.hir.local_def_id(node_id);
125 let def_path_hash = self.tcx.def_path_hash(def_id);
127 if attr.check_name(ATTR_IF_THIS_CHANGED) {
128 let dep_node_interned = self.argument(attr);
129 let dep_node = match dep_node_interned {
130 None => def_path_hash.to_dep_node(DepKind::Hir),
132 match DepNode::from_label_string(&n.as_str(), def_path_hash) {
135 self.tcx.sess.span_fatal(
137 &format!("unrecognized DepNode variant {:?}", n));
142 self.if_this_changed.push((attr.span, def_id, dep_node));
143 } else if attr.check_name(ATTR_THEN_THIS_WOULD_NEED) {
144 let dep_node_interned = self.argument(attr);
145 let dep_node = match dep_node_interned {
147 match DepNode::from_label_string(&n.as_str(), def_path_hash) {
150 self.tcx.sess.span_fatal(
152 &format!("unrecognized DepNode variant {:?}", n));
157 self.tcx.sess.span_fatal(
159 "missing DepNode variant");
162 self.then_this_would_need.push((attr.span,
163 dep_node_interned.unwrap(),
171 impl<'a, 'tcx> Visitor<'tcx> for IfThisChanged<'a, 'tcx> {
172 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
173 NestedVisitorMap::OnlyBodies(&self.tcx.hir)
176 fn visit_item(&mut self, item: &'tcx hir::Item) {
177 self.process_attrs(item.id, &item.attrs);
178 intravisit::walk_item(self, item);
181 fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
182 self.process_attrs(trait_item.id, &trait_item.attrs);
183 intravisit::walk_trait_item(self, trait_item);
186 fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
187 self.process_attrs(impl_item.id, &impl_item.attrs);
188 intravisit::walk_impl_item(self, impl_item);
191 fn visit_struct_field(&mut self, s: &'tcx hir::StructField) {
192 self.process_attrs(s.id, &s.attrs);
193 intravisit::walk_struct_field(self, s);
197 fn check_paths<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
198 if_this_changed: &Sources,
199 then_this_would_need: &Targets)
201 // Return early here so as not to construct the query, which is not cheap.
202 if if_this_changed.is_empty() {
203 for &(target_span, _, _, _) in then_this_would_need {
206 "no #[rustc_if_this_changed] annotation detected");
211 let query = tcx.dep_graph.query();
212 for &(_, source_def_id, ref source_dep_node) in if_this_changed {
213 let dependents = query.transitive_predecessors(source_dep_node);
214 for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
215 if !dependents.contains(&target_dep_node) {
218 &format!("no path from `{}` to `{}`",
219 tcx.item_path_str(source_def_id),
230 fn dump_graph(tcx: TyCtxt) {
231 let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
232 let query = tcx.dep_graph.query();
234 let nodes = match env::var("RUST_DEP_GRAPH_FILTER") {
236 // Expect one of: "-> target", "source -> target", or "source ->".
237 let edge_filter = EdgeFilter::new(&string).unwrap_or_else(|e| {
238 bug!("invalid filter: {}", e)
240 let sources = node_set(&query, &edge_filter.source);
241 let targets = node_set(&query, &edge_filter.target);
242 filter_nodes(&query, &sources, &targets)
250 let edges = filter_edges(&query, &nodes);
252 { // dump a .txt file with just the edges:
253 let txt_path = format!("{}.txt", path);
254 let mut file = File::create(&txt_path).unwrap();
255 for &(ref source, ref target) in &edges {
256 write!(file, "{:?} -> {:?}\n", source, target).unwrap();
260 { // dump a .dot file in graphviz format:
261 let dot_path = format!("{}.dot", path);
262 let mut v = Vec::new();
263 dot::render(&GraphvizDepGraph(nodes, edges), &mut v).unwrap();
264 fs::write(dot_path, v).unwrap();
268 pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>,
269 Vec<(&'q DepNode, &'q DepNode)>);
271 impl<'a, 'tcx, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
272 type Node = &'q DepNode;
273 type Edge = (&'q DepNode, &'q DepNode);
274 fn nodes(&self) -> dot::Nodes<&'q DepNode> {
275 let nodes: Vec<_> = self.0.iter().cloned().collect();
278 fn edges(&self) -> dot::Edges<(&'q DepNode, &'q DepNode)> {
281 fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
284 fn target(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
289 impl<'a, 'tcx, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
290 type Node = &'q DepNode;
291 type Edge = (&'q DepNode, &'q DepNode);
292 fn graph_id(&self) -> dot::Id {
293 dot::Id::new("DependencyGraph").unwrap()
295 fn node_id(&self, n: &&'q DepNode) -> dot::Id {
297 format!("{:?}", n).chars()
298 .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
300 debug!("n={:?} s={:?}", n, s);
301 dot::Id::new(s).unwrap()
303 fn node_label(&self, n: &&'q DepNode) -> dot::LabelText {
304 dot::LabelText::label(format!("{:?}", n))
308 // Given an optional filter like `"x,y,z"`, returns either `None` (no
309 // filter) or the set of nodes whose labels contain all of those
311 fn node_set<'q>(query: &'q DepGraphQuery, filter: &DepNodeFilter)
312 -> Option<FxHashSet<&'q DepNode>>
314 debug!("node_set(filter={:?})", filter);
316 if filter.accepts_all() {
320 Some(query.nodes().into_iter().filter(|n| filter.test(n)).collect())
323 fn filter_nodes<'q>(query: &'q DepGraphQuery,
324 sources: &Option<FxHashSet<&'q DepNode>>,
325 targets: &Option<FxHashSet<&'q DepNode>>)
326 -> FxHashSet<&'q DepNode>
328 if let &Some(ref sources) = sources {
329 if let &Some(ref targets) = targets {
330 walk_between(query, sources, targets)
332 walk_nodes(query, sources, OUTGOING)
334 } else if let &Some(ref targets) = targets {
335 walk_nodes(query, targets, INCOMING)
337 query.nodes().into_iter().collect()
341 fn walk_nodes<'q>(query: &'q DepGraphQuery,
342 starts: &FxHashSet<&'q DepNode>,
343 direction: Direction)
344 -> FxHashSet<&'q DepNode>
346 let mut set = FxHashSet();
347 for &start in starts {
348 debug!("walk_nodes: start={:?} outgoing?={:?}", start, direction == OUTGOING);
349 if set.insert(start) {
350 let mut stack = vec![query.indices[start]];
351 while let Some(index) = stack.pop() {
352 for (_, edge) in query.graph.adjacent_edges(index, direction) {
353 let neighbor_index = edge.source_or_target(direction);
354 let neighbor = query.graph.node_data(neighbor_index);
355 if set.insert(neighbor) {
356 stack.push(neighbor_index);
365 fn walk_between<'q>(query: &'q DepGraphQuery,
366 sources: &FxHashSet<&'q DepNode>,
367 targets: &FxHashSet<&'q DepNode>)
368 -> FxHashSet<&'q DepNode>
370 // This is a bit tricky. We want to include a node only if it is:
371 // (a) reachable from a source and (b) will reach a target. And we
372 // have to be careful about cycles etc. Luckily efficiency is not
375 #[derive(Copy, Clone, PartialEq)]
376 enum State { Undecided, Deciding, Included, Excluded }
378 let mut node_states = vec![State::Undecided; query.graph.len_nodes()];
380 for &target in targets {
381 node_states[query.indices[target].0] = State::Included;
384 for source in sources.iter().map(|&n| query.indices[n]) {
385 recurse(query, &mut node_states, source);
391 let index = query.indices[n];
392 node_states[index.0] == State::Included
396 fn recurse(query: &DepGraphQuery,
397 node_states: &mut [State],
401 match node_states[node.0] {
402 // known to reach a target
403 State::Included => return true,
405 // known not to reach a target
406 State::Excluded => return false,
408 // backedge, not yet known, say false
409 State::Deciding => return false,
411 State::Undecided => { }
414 node_states[node.0] = State::Deciding;
416 for neighbor_index in query.graph.successor_nodes(node) {
417 if recurse(query, node_states, neighbor_index) {
418 node_states[node.0] = State::Included;
422 // if we didn't find a path to target, then set to excluded
423 if node_states[node.0] == State::Deciding {
424 node_states[node.0] = State::Excluded;
427 assert!(node_states[node.0] == State::Included);
433 fn filter_edges<'q>(query: &'q DepGraphQuery,
434 nodes: &FxHashSet<&'q DepNode>)
435 -> Vec<(&'q DepNode, &'q DepNode)>
439 .filter(|&(source, target)| nodes.contains(source) && nodes.contains(target))