clang  3.9.0
ASTMatchFinder.cpp
Go to the documentation of this file.
1 //===--- ASTMatchFinder.cpp - Structural query framework ------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Implements an algorithm to efficiently search for matches on AST nodes.
11 // Uses memoization to support recursive matches like HasDescendant.
12 //
13 // The general idea is to visit all AST nodes with a RecursiveASTVisitor,
14 // calling the Matches(...) method of each matcher we are running on each
15 // AST node. The matcher can recurse via the ASTMatchFinder interface.
16 //
17 //===----------------------------------------------------------------------===//
18 
20 #include "clang/AST/ASTConsumer.h"
21 #include "clang/AST/ASTContext.h"
23 #include "llvm/ADT/DenseMap.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/Support/Timer.h"
26 #include <deque>
27 #include <memory>
28 #include <set>
29 
30 namespace clang {
31 namespace ast_matchers {
32 namespace internal {
33 namespace {
34 
35 typedef MatchFinder::MatchCallback MatchCallback;
36 
37 // The maximum number of memoization entries to store.
38 // 10k has been experimentally found to give a good trade-off
39 // of performance vs. memory consumption by running matcher
40 // that match on every statement over a very large codebase.
41 //
42 // FIXME: Do some performance optimization in general and
43 // revisit this number; also, put up micro-benchmarks that we can
44 // optimize this on.
45 static const unsigned MaxMemoizationEntries = 10000;
46 
47 // We use memoization to avoid running the same matcher on the same
48 // AST node twice. This struct is the key for looking up match
49 // result. It consists of an ID of the MatcherInterface (for
50 // identifying the matcher), a pointer to the AST node and the
51 // bound nodes before the matcher was executed.
52 //
53 // We currently only memoize on nodes whose pointers identify the
54 // nodes (\c Stmt and \c Decl, but not \c QualType or \c TypeLoc).
55 // For \c QualType and \c TypeLoc it is possible to implement
56 // generation of keys for each type.
57 // FIXME: Benchmark whether memoization of non-pointer typed nodes
58 // provides enough benefit for the additional amount of code.
59 struct MatchKey {
60  DynTypedMatcher::MatcherIDType MatcherID;
61  ast_type_traits::DynTypedNode Node;
62  BoundNodesTreeBuilder BoundNodes;
63 
64  bool operator<(const MatchKey &Other) const {
65  return std::tie(MatcherID, Node, BoundNodes) <
66  std::tie(Other.MatcherID, Other.Node, Other.BoundNodes);
67  }
68 };
69 
70 // Used to store the result of a match and possibly bound nodes.
71 struct MemoizedMatchResult {
73  BoundNodesTreeBuilder Nodes;
74 };
75 
76 // A RecursiveASTVisitor that traverses all children or all descendants of
77 // a node.
78 class MatchChildASTVisitor
79  : public RecursiveASTVisitor<MatchChildASTVisitor> {
80 public:
81  typedef RecursiveASTVisitor<MatchChildASTVisitor> VisitorBase;
82 
83  // Creates an AST visitor that matches 'matcher' on all children or
84  // descendants of a traversed node. max_depth is the maximum depth
85  // to traverse: use 1 for matching the children and INT_MAX for
86  // matching the descendants.
87  MatchChildASTVisitor(const DynTypedMatcher *Matcher,
88  ASTMatchFinder *Finder,
89  BoundNodesTreeBuilder *Builder,
90  int MaxDepth,
91  ASTMatchFinder::TraversalKind Traversal,
92  ASTMatchFinder::BindKind Bind)
93  : Matcher(Matcher),
94  Finder(Finder),
95  Builder(Builder),
96  CurrentDepth(0),
97  MaxDepth(MaxDepth),
98  Traversal(Traversal),
99  Bind(Bind),
100  Matches(false) {}
101 
102  // Returns true if a match is found in the subtree rooted at the
103  // given AST node. This is done via a set of mutually recursive
104  // functions. Here's how the recursion is done (the *wildcard can
105  // actually be Decl, Stmt, or Type):
106  //
107  // - Traverse(node) calls BaseTraverse(node) when it needs
108  // to visit the descendants of node.
109  // - BaseTraverse(node) then calls (via VisitorBase::Traverse*(node))
110  // Traverse*(c) for each child c of 'node'.
111  // - Traverse*(c) in turn calls Traverse(c), completing the
112  // recursion.
113  bool findMatch(const ast_type_traits::DynTypedNode &DynNode) {
114  reset();
115  if (const Decl *D = DynNode.get<Decl>())
116  traverse(*D);
117  else if (const Stmt *S = DynNode.get<Stmt>())
118  traverse(*S);
119  else if (const NestedNameSpecifier *NNS =
120  DynNode.get<NestedNameSpecifier>())
121  traverse(*NNS);
122  else if (const NestedNameSpecifierLoc *NNSLoc =
123  DynNode.get<NestedNameSpecifierLoc>())
124  traverse(*NNSLoc);
125  else if (const QualType *Q = DynNode.get<QualType>())
126  traverse(*Q);
127  else if (const TypeLoc *T = DynNode.get<TypeLoc>())
128  traverse(*T);
129  // FIXME: Add other base types after adding tests.
130 
131  // It's OK to always overwrite the bound nodes, as if there was
132  // no match in this recursive branch, the result set is empty
133  // anyway.
134  *Builder = ResultBindings;
135 
136  return Matches;
137  }
138 
139  // The following are overriding methods from the base visitor class.
140  // They are public only to allow CRTP to work. They are *not *part
141  // of the public API of this class.
142  bool TraverseDecl(Decl *DeclNode) {
143  ScopedIncrement ScopedDepth(&CurrentDepth);
144  return (DeclNode == nullptr) || traverse(*DeclNode);
145  }
146  bool TraverseStmt(Stmt *StmtNode) {
147  ScopedIncrement ScopedDepth(&CurrentDepth);
148  const Stmt *StmtToTraverse = StmtNode;
149  if (Traversal ==
150  ASTMatchFinder::TK_IgnoreImplicitCastsAndParentheses) {
151  const Expr *ExprNode = dyn_cast_or_null<Expr>(StmtNode);
152  if (ExprNode) {
153  StmtToTraverse = ExprNode->IgnoreParenImpCasts();
154  }
155  }
156  return (StmtToTraverse == nullptr) || traverse(*StmtToTraverse);
157  }
158  // We assume that the QualType and the contained type are on the same
159  // hierarchy level. Thus, we try to match either of them.
160  bool TraverseType(QualType TypeNode) {
161  if (TypeNode.isNull())
162  return true;
163  ScopedIncrement ScopedDepth(&CurrentDepth);
164  // Match the Type.
165  if (!match(*TypeNode))
166  return false;
167  // The QualType is matched inside traverse.
168  return traverse(TypeNode);
169  }
170  // We assume that the TypeLoc, contained QualType and contained Type all are
171  // on the same hierarchy level. Thus, we try to match all of them.
172  bool TraverseTypeLoc(TypeLoc TypeLocNode) {
173  if (TypeLocNode.isNull())
174  return true;
175  ScopedIncrement ScopedDepth(&CurrentDepth);
176  // Match the Type.
177  if (!match(*TypeLocNode.getType()))
178  return false;
179  // Match the QualType.
180  if (!match(TypeLocNode.getType()))
181  return false;
182  // The TypeLoc is matched inside traverse.
183  return traverse(TypeLocNode);
184  }
185  bool TraverseNestedNameSpecifier(NestedNameSpecifier *NNS) {
186  ScopedIncrement ScopedDepth(&CurrentDepth);
187  return (NNS == nullptr) || traverse(*NNS);
188  }
189  bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS) {
190  if (!NNS)
191  return true;
192  ScopedIncrement ScopedDepth(&CurrentDepth);
193  if (!match(*NNS.getNestedNameSpecifier()))
194  return false;
195  return traverse(NNS);
196  }
197 
198  bool shouldVisitTemplateInstantiations() const { return true; }
199  bool shouldVisitImplicitCode() const { return true; }
200 
201 private:
202  // Used for updating the depth during traversal.
203  struct ScopedIncrement {
204  explicit ScopedIncrement(int *Depth) : Depth(Depth) { ++(*Depth); }
205  ~ScopedIncrement() { --(*Depth); }
206 
207  private:
208  int *Depth;
209  };
210 
211  // Resets the state of this object.
212  void reset() {
213  Matches = false;
214  CurrentDepth = 0;
215  }
216 
217  // Forwards the call to the corresponding Traverse*() method in the
218  // base visitor class.
219  bool baseTraverse(const Decl &DeclNode) {
220  return VisitorBase::TraverseDecl(const_cast<Decl*>(&DeclNode));
221  }
222  bool baseTraverse(const Stmt &StmtNode) {
223  return VisitorBase::TraverseStmt(const_cast<Stmt*>(&StmtNode));
224  }
225  bool baseTraverse(QualType TypeNode) {
226  return VisitorBase::TraverseType(TypeNode);
227  }
228  bool baseTraverse(TypeLoc TypeLocNode) {
229  return VisitorBase::TraverseTypeLoc(TypeLocNode);
230  }
231  bool baseTraverse(const NestedNameSpecifier &NNS) {
233  const_cast<NestedNameSpecifier*>(&NNS));
234  }
235  bool baseTraverse(NestedNameSpecifierLoc NNS) {
237  }
238 
239  // Sets 'Matched' to true if 'Matcher' matches 'Node' and:
240  // 0 < CurrentDepth <= MaxDepth.
241  //
242  // Returns 'true' if traversal should continue after this function
243  // returns, i.e. if no match is found or 'Bind' is 'BK_All'.
244  template <typename T>
245  bool match(const T &Node) {
246  if (CurrentDepth == 0 || CurrentDepth > MaxDepth) {
247  return true;
248  }
249  if (Bind != ASTMatchFinder::BK_All) {
250  BoundNodesTreeBuilder RecursiveBuilder(*Builder);
251  if (Matcher->matches(ast_type_traits::DynTypedNode::create(Node), Finder,
252  &RecursiveBuilder)) {
253  Matches = true;
254  ResultBindings.addMatch(RecursiveBuilder);
255  return false; // Abort as soon as a match is found.
256  }
257  } else {
258  BoundNodesTreeBuilder RecursiveBuilder(*Builder);
259  if (Matcher->matches(ast_type_traits::DynTypedNode::create(Node), Finder,
260  &RecursiveBuilder)) {
261  // After the first match the matcher succeeds.
262  Matches = true;
263  ResultBindings.addMatch(RecursiveBuilder);
264  }
265  }
266  return true;
267  }
268 
269  // Traverses the subtree rooted at 'Node'; returns true if the
270  // traversal should continue after this function returns.
271  template <typename T>
272  bool traverse(const T &Node) {
273  static_assert(IsBaseType<T>::value,
274  "traverse can only be instantiated with base type");
275  if (!match(Node))
276  return false;
277  return baseTraverse(Node);
278  }
279 
280  const DynTypedMatcher *const Matcher;
281  ASTMatchFinder *const Finder;
282  BoundNodesTreeBuilder *const Builder;
283  BoundNodesTreeBuilder ResultBindings;
285  const int MaxDepth;
286  const ASTMatchFinder::TraversalKind Traversal;
287  const ASTMatchFinder::BindKind Bind;
288  bool Matches;
289 };
290 
291 // Controls the outermost traversal of the AST and allows to match multiple
292 // matchers.
293 class MatchASTVisitor : public RecursiveASTVisitor<MatchASTVisitor>,
294  public ASTMatchFinder {
295 public:
296  MatchASTVisitor(const MatchFinder::MatchersByType *Matchers,
297  const MatchFinder::MatchFinderOptions &Options)
298  : Matchers(Matchers), Options(Options), ActiveASTContext(nullptr) {}
299 
300  ~MatchASTVisitor() override {
301  if (Options.CheckProfiling) {
302  Options.CheckProfiling->Records = std::move(TimeByBucket);
303  }
304  }
305 
306  void onStartOfTranslationUnit() {
307  const bool EnableCheckProfiling = Options.CheckProfiling.hasValue();
308  TimeBucketRegion Timer;
309  for (MatchCallback *MC : Matchers->AllCallbacks) {
310  if (EnableCheckProfiling)
311  Timer.setBucket(&TimeByBucket[MC->getID()]);
312  MC->onStartOfTranslationUnit();
313  }
314  }
315 
316  void onEndOfTranslationUnit() {
317  const bool EnableCheckProfiling = Options.CheckProfiling.hasValue();
318  TimeBucketRegion Timer;
319  for (MatchCallback *MC : Matchers->AllCallbacks) {
320  if (EnableCheckProfiling)
321  Timer.setBucket(&TimeByBucket[MC->getID()]);
322  MC->onEndOfTranslationUnit();
323  }
324  }
325 
326  void set_active_ast_context(ASTContext *NewActiveASTContext) {
327  ActiveASTContext = NewActiveASTContext;
328  }
329 
330  // The following Visit*() and Traverse*() functions "override"
331  // methods in RecursiveASTVisitor.
332 
333  bool VisitTypedefNameDecl(TypedefNameDecl *DeclNode) {
334  // When we see 'typedef A B', we add name 'B' to the set of names
335  // A's canonical type maps to. This is necessary for implementing
336  // isDerivedFrom(x) properly, where x can be the name of the base
337  // class or any of its aliases.
338  //
339  // In general, the is-alias-of (as defined by typedefs) relation
340  // is tree-shaped, as you can typedef a type more than once. For
341  // example,
342  //
343  // typedef A B;
344  // typedef A C;
345  // typedef C D;
346  // typedef C E;
347  //
348  // gives you
349  //
350  // A
351  // |- B
352  // `- C
353  // |- D
354  // `- E
355  //
356  // It is wrong to assume that the relation is a chain. A correct
357  // implementation of isDerivedFrom() needs to recognize that B and
358  // E are aliases, even though neither is a typedef of the other.
359  // Therefore, we cannot simply walk through one typedef chain to
360  // find out whether the type name matches.
361  const Type *TypeNode = DeclNode->getUnderlyingType().getTypePtr();
362  const Type *CanonicalType = // root of the typedef tree
363  ActiveASTContext->getCanonicalType(TypeNode);
364  TypeAliases[CanonicalType].insert(DeclNode);
365  return true;
366  }
367 
368  bool TraverseDecl(Decl *DeclNode);
369  bool TraverseStmt(Stmt *StmtNode);
370  bool TraverseType(QualType TypeNode);
371  bool TraverseTypeLoc(TypeLoc TypeNode);
372  bool TraverseNestedNameSpecifier(NestedNameSpecifier *NNS);
373  bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS);
374 
375  // Matches children or descendants of 'Node' with 'BaseMatcher'.
376  bool memoizedMatchesRecursively(const ast_type_traits::DynTypedNode &Node,
377  const DynTypedMatcher &Matcher,
378  BoundNodesTreeBuilder *Builder, int MaxDepth,
379  TraversalKind Traversal, BindKind Bind) {
380  // For AST-nodes that don't have an identity, we can't memoize.
381  if (!Node.getMemoizationData() || !Builder->isComparable())
382  return matchesRecursively(Node, Matcher, Builder, MaxDepth, Traversal,
383  Bind);
384 
385  MatchKey Key;
386  Key.MatcherID = Matcher.getID();
387  Key.Node = Node;
388  // Note that we key on the bindings *before* the match.
389  Key.BoundNodes = *Builder;
390 
392  if (I != ResultCache.end()) {
393  *Builder = I->second.Nodes;
394  return I->second.ResultOfMatch;
395  }
396 
397  MemoizedMatchResult Result;
398  Result.Nodes = *Builder;
399  Result.ResultOfMatch = matchesRecursively(Node, Matcher, &Result.Nodes,
400  MaxDepth, Traversal, Bind);
401 
402  MemoizedMatchResult &CachedResult = ResultCache[Key];
403  CachedResult = std::move(Result);
404 
405  *Builder = CachedResult.Nodes;
406  return CachedResult.ResultOfMatch;
407  }
408 
409  // Matches children or descendants of 'Node' with 'BaseMatcher'.
410  bool matchesRecursively(const ast_type_traits::DynTypedNode &Node,
411  const DynTypedMatcher &Matcher,
412  BoundNodesTreeBuilder *Builder, int MaxDepth,
413  TraversalKind Traversal, BindKind Bind) {
414  MatchChildASTVisitor Visitor(
415  &Matcher, this, Builder, MaxDepth, Traversal, Bind);
416  return Visitor.findMatch(Node);
417  }
418 
419  bool classIsDerivedFrom(const CXXRecordDecl *Declaration,
420  const Matcher<NamedDecl> &Base,
421  BoundNodesTreeBuilder *Builder) override;
422 
423  // Implements ASTMatchFinder::matchesChildOf.
424  bool matchesChildOf(const ast_type_traits::DynTypedNode &Node,
425  const DynTypedMatcher &Matcher,
426  BoundNodesTreeBuilder *Builder,
427  TraversalKind Traversal,
428  BindKind Bind) override {
429  if (ResultCache.size() > MaxMemoizationEntries)
430  ResultCache.clear();
431  return memoizedMatchesRecursively(Node, Matcher, Builder, 1, Traversal,
432  Bind);
433  }
434  // Implements ASTMatchFinder::matchesDescendantOf.
435  bool matchesDescendantOf(const ast_type_traits::DynTypedNode &Node,
436  const DynTypedMatcher &Matcher,
437  BoundNodesTreeBuilder *Builder,
438  BindKind Bind) override {
439  if (ResultCache.size() > MaxMemoizationEntries)
440  ResultCache.clear();
441  return memoizedMatchesRecursively(Node, Matcher, Builder, INT_MAX,
442  TK_AsIs, Bind);
443  }
444  // Implements ASTMatchFinder::matchesAncestorOf.
445  bool matchesAncestorOf(const ast_type_traits::DynTypedNode &Node,
446  const DynTypedMatcher &Matcher,
447  BoundNodesTreeBuilder *Builder,
448  AncestorMatchMode MatchMode) override {
449  // Reset the cache outside of the recursive call to make sure we
450  // don't invalidate any iterators.
451  if (ResultCache.size() > MaxMemoizationEntries)
452  ResultCache.clear();
453  return memoizedMatchesAncestorOfRecursively(Node, Matcher, Builder,
454  MatchMode);
455  }
456 
457  // Matches all registered matchers on the given node and calls the
458  // result callback for every node that matches.
459  void match(const ast_type_traits::DynTypedNode &Node) {
460  // FIXME: Improve this with a switch or a visitor pattern.
461  if (auto *N = Node.get<Decl>()) {
462  match(*N);
463  } else if (auto *N = Node.get<Stmt>()) {
464  match(*N);
465  } else if (auto *N = Node.get<Type>()) {
466  match(*N);
467  } else if (auto *N = Node.get<QualType>()) {
468  match(*N);
469  } else if (auto *N = Node.get<NestedNameSpecifier>()) {
470  match(*N);
471  } else if (auto *N = Node.get<NestedNameSpecifierLoc>()) {
472  match(*N);
473  } else if (auto *N = Node.get<TypeLoc>()) {
474  match(*N);
475  }
476  }
477 
478  template <typename T> void match(const T &Node) {
479  matchDispatch(&Node);
480  }
481 
482  // Implements ASTMatchFinder::getASTContext.
483  ASTContext &getASTContext() const override { return *ActiveASTContext; }
484 
485  bool shouldVisitTemplateInstantiations() const { return true; }
486  bool shouldVisitImplicitCode() const { return true; }
487 
488 private:
489  class TimeBucketRegion {
490  public:
491  TimeBucketRegion() : Bucket(nullptr) {}
492  ~TimeBucketRegion() { setBucket(nullptr); }
493 
494  /// \brief Start timing for \p NewBucket.
495  ///
496  /// If there was a bucket already set, it will finish the timing for that
497  /// other bucket.
498  /// \p NewBucket will be timed until the next call to \c setBucket() or
499  /// until the \c TimeBucketRegion is destroyed.
500  /// If \p NewBucket is the same as the currently timed bucket, this call
501  /// does nothing.
502  void setBucket(llvm::TimeRecord *NewBucket) {
503  if (Bucket != NewBucket) {
504  auto Now = llvm::TimeRecord::getCurrentTime(true);
505  if (Bucket)
506  *Bucket += Now;
507  if (NewBucket)
508  *NewBucket -= Now;
509  Bucket = NewBucket;
510  }
511  }
512 
513  private:
514  llvm::TimeRecord *Bucket;
515  };
516 
517  /// \brief Runs all the \p Matchers on \p Node.
518  ///
519  /// Used by \c matchDispatch() below.
520  template <typename T, typename MC>
521  void matchWithoutFilter(const T &Node, const MC &Matchers) {
522  const bool EnableCheckProfiling = Options.CheckProfiling.hasValue();
523  TimeBucketRegion Timer;
524  for (const auto &MP : Matchers) {
525  if (EnableCheckProfiling)
526  Timer.setBucket(&TimeByBucket[MP.second->getID()]);
527  BoundNodesTreeBuilder Builder;
528  if (MP.first.matches(Node, this, &Builder)) {
529  MatchVisitor Visitor(ActiveASTContext, MP.second);
530  Builder.visitMatches(&Visitor);
531  }
532  }
533  }
534 
535  void matchWithFilter(const ast_type_traits::DynTypedNode &DynNode) {
536  auto Kind = DynNode.getNodeKind();
537  auto it = MatcherFiltersMap.find(Kind);
538  const auto &Filter =
539  it != MatcherFiltersMap.end() ? it->second : getFilterForKind(Kind);
540 
541  if (Filter.empty())
542  return;
543 
544  const bool EnableCheckProfiling = Options.CheckProfiling.hasValue();
545  TimeBucketRegion Timer;
546  auto &Matchers = this->Matchers->DeclOrStmt;
547  for (unsigned short I : Filter) {
548  auto &MP = Matchers[I];
549  if (EnableCheckProfiling)
550  Timer.setBucket(&TimeByBucket[MP.second->getID()]);
551  BoundNodesTreeBuilder Builder;
552  if (MP.first.matchesNoKindCheck(DynNode, this, &Builder)) {
553  MatchVisitor Visitor(ActiveASTContext, MP.second);
554  Builder.visitMatches(&Visitor);
555  }
556  }
557  }
558 
559  const std::vector<unsigned short> &
560  getFilterForKind(ast_type_traits::ASTNodeKind Kind) {
561  auto &Filter = MatcherFiltersMap[Kind];
562  auto &Matchers = this->Matchers->DeclOrStmt;
563  assert((Matchers.size() < USHRT_MAX) && "Too many matchers.");
564  for (unsigned I = 0, E = Matchers.size(); I != E; ++I) {
565  if (Matchers[I].first.canMatchNodesOfKind(Kind)) {
566  Filter.push_back(I);
567  }
568  }
569  return Filter;
570  }
571 
572  /// @{
573  /// \brief Overloads to pair the different node types to their matchers.
574  void matchDispatch(const Decl *Node) {
575  return matchWithFilter(ast_type_traits::DynTypedNode::create(*Node));
576  }
577  void matchDispatch(const Stmt *Node) {
578  return matchWithFilter(ast_type_traits::DynTypedNode::create(*Node));
579  }
580 
581  void matchDispatch(const Type *Node) {
582  matchWithoutFilter(QualType(Node, 0), Matchers->Type);
583  }
584  void matchDispatch(const TypeLoc *Node) {
585  matchWithoutFilter(*Node, Matchers->TypeLoc);
586  }
587  void matchDispatch(const QualType *Node) {
588  matchWithoutFilter(*Node, Matchers->Type);
589  }
590  void matchDispatch(const NestedNameSpecifier *Node) {
591  matchWithoutFilter(*Node, Matchers->NestedNameSpecifier);
592  }
593  void matchDispatch(const NestedNameSpecifierLoc *Node) {
594  matchWithoutFilter(*Node, Matchers->NestedNameSpecifierLoc);
595  }
596  void matchDispatch(const void *) { /* Do nothing. */ }
597  /// @}
598 
599  // Returns whether an ancestor of \p Node matches \p Matcher.
600  //
601  // The order of matching ((which can lead to different nodes being bound in
602  // case there are multiple matches) is breadth first search.
603  //
604  // To allow memoization in the very common case of having deeply nested
605  // expressions inside a template function, we first walk up the AST, memoizing
606  // the result of the match along the way, as long as there is only a single
607  // parent.
608  //
609  // Once there are multiple parents, the breadth first search order does not
610  // allow simple memoization on the ancestors. Thus, we only memoize as long
611  // as there is a single parent.
612  bool memoizedMatchesAncestorOfRecursively(
613  const ast_type_traits::DynTypedNode &Node, const DynTypedMatcher &Matcher,
614  BoundNodesTreeBuilder *Builder, AncestorMatchMode MatchMode) {
615  if (Node.get<TranslationUnitDecl>() ==
616  ActiveASTContext->getTranslationUnitDecl())
617  return false;
618 
619  // For AST-nodes that don't have an identity, we can't memoize.
620  if (!Builder->isComparable())
621  return matchesAncestorOfRecursively(Node, Matcher, Builder, MatchMode);
622 
623  MatchKey Key;
624  Key.MatcherID = Matcher.getID();
625  Key.Node = Node;
626  Key.BoundNodes = *Builder;
627 
628  // Note that we cannot use insert and reuse the iterator, as recursive
629  // calls to match might invalidate the result cache iterators.
631  if (I != ResultCache.end()) {
632  *Builder = I->second.Nodes;
633  return I->second.ResultOfMatch;
634  }
635 
636  MemoizedMatchResult Result;
637  Result.Nodes = *Builder;
638  Result.ResultOfMatch =
639  matchesAncestorOfRecursively(Node, Matcher, &Result.Nodes, MatchMode);
640 
641  MemoizedMatchResult &CachedResult = ResultCache[Key];
642  CachedResult = std::move(Result);
643 
644  *Builder = CachedResult.Nodes;
645  return CachedResult.ResultOfMatch;
646  }
647 
648  bool matchesAncestorOfRecursively(const ast_type_traits::DynTypedNode &Node,
649  const DynTypedMatcher &Matcher,
650  BoundNodesTreeBuilder *Builder,
651  AncestorMatchMode MatchMode) {
652  const auto &Parents = ActiveASTContext->getParents(Node);
653  assert(!Parents.empty() && "Found node that is not in the parent map.");
654  if (Parents.size() == 1) {
655  // Only one parent - do recursive memoization.
656  const ast_type_traits::DynTypedNode Parent = Parents[0];
657  BoundNodesTreeBuilder BuilderCopy = *Builder;
658  if (Matcher.matches(Parent, this, &BuilderCopy)) {
659  *Builder = std::move(BuilderCopy);
660  return true;
661  }
662  if (MatchMode != ASTMatchFinder::AMM_ParentOnly) {
663  return memoizedMatchesAncestorOfRecursively(Parent, Matcher, Builder,
664  MatchMode);
665  // Once we get back from the recursive call, the result will be the
666  // same as the parent's result.
667  }
668  } else {
669  // Multiple parents - BFS over the rest of the nodes.
671  std::deque<ast_type_traits::DynTypedNode> Queue(Parents.begin(),
672  Parents.end());
673  while (!Queue.empty()) {
674  BoundNodesTreeBuilder BuilderCopy = *Builder;
675  if (Matcher.matches(Queue.front(), this, &BuilderCopy)) {
676  *Builder = std::move(BuilderCopy);
677  return true;
678  }
679  if (MatchMode != ASTMatchFinder::AMM_ParentOnly) {
680  for (const auto &Parent :
681  ActiveASTContext->getParents(Queue.front())) {
682  // Make sure we do not visit the same node twice.
683  // Otherwise, we'll visit the common ancestors as often as there
684  // are splits on the way down.
685  if (Visited.insert(Parent.getMemoizationData()).second)
686  Queue.push_back(Parent);
687  }
688  }
689  Queue.pop_front();
690  }
691  }
692  return false;
693  }
694 
695  // Implements a BoundNodesTree::Visitor that calls a MatchCallback with
696  // the aggregated bound nodes for each match.
697  class MatchVisitor : public BoundNodesTreeBuilder::Visitor {
698  public:
699  MatchVisitor(ASTContext* Context,
700  MatchFinder::MatchCallback* Callback)
701  : Context(Context),
702  Callback(Callback) {}
703 
704  void visitMatch(const BoundNodes& BoundNodesView) override {
705  Callback->run(MatchFinder::MatchResult(BoundNodesView, Context));
706  }
707 
708  private:
710  MatchFinder::MatchCallback* Callback;
711  };
712 
713  // Returns true if 'TypeNode' has an alias that matches the given matcher.
714  bool typeHasMatchingAlias(const Type *TypeNode,
715  const Matcher<NamedDecl> &Matcher,
716  BoundNodesTreeBuilder *Builder) {
717  const Type *const CanonicalType =
718  ActiveASTContext->getCanonicalType(TypeNode);
719  for (const TypedefNameDecl *Alias : TypeAliases.lookup(CanonicalType)) {
720  BoundNodesTreeBuilder Result(*Builder);
721  if (Matcher.matches(*Alias, this, &Result)) {
722  *Builder = std::move(Result);
723  return true;
724  }
725  }
726  return false;
727  }
728 
729  /// \brief Bucket to record map.
730  ///
731  /// Used to get the appropriate bucket for each matcher.
732  llvm::StringMap<llvm::TimeRecord> TimeByBucket;
733 
734  const MatchFinder::MatchersByType *Matchers;
735 
736  /// \brief Filtered list of matcher indices for each matcher kind.
737  ///
738  /// \c Decl and \c Stmt toplevel matchers usually apply to a specific node
739  /// kind (and derived kinds) so it is a waste to try every matcher on every
740  /// node.
741  /// We precalculate a list of matchers that pass the toplevel restrict check.
742  /// This also allows us to skip the restrict check at matching time. See
743  /// use \c matchesNoKindCheck() above.
744  llvm::DenseMap<ast_type_traits::ASTNodeKind, std::vector<unsigned short>>
746 
747  const MatchFinder::MatchFinderOptions &Options;
749 
750  // Maps a canonical type to its TypedefDecls.
751  llvm::DenseMap<const Type*, std::set<const TypedefNameDecl*> > TypeAliases;
752 
753  // Maps (matcher, node) -> the match result for memoization.
754  typedef std::map<MatchKey, MemoizedMatchResult> MemoizationMap;
755  MemoizationMap ResultCache;
756 };
757 
758 static CXXRecordDecl *
759 getAsCXXRecordDeclOrPrimaryTemplate(const Type *TypeNode) {
760  if (auto *RD = TypeNode->getAsCXXRecordDecl())
761  return RD;
762 
763  // Find the innermost TemplateSpecializationType that isn't an alias template.
764  auto *TemplateType = TypeNode->getAs<TemplateSpecializationType>();
765  while (TemplateType && TemplateType->isTypeAlias())
766  TemplateType =
767  TemplateType->getAliasedType()->getAs<TemplateSpecializationType>();
768 
769  // If this is the name of a (dependent) template specialization, use the
770  // definition of the template, even though it might be specialized later.
771  if (TemplateType)
772  if (auto *ClassTemplate = dyn_cast_or_null<ClassTemplateDecl>(
773  TemplateType->getTemplateName().getAsTemplateDecl()))
774  return ClassTemplate->getTemplatedDecl();
775 
776  return nullptr;
777 }
778 
779 // Returns true if the given class is directly or indirectly derived
780 // from a base type with the given name. A class is not considered to be
781 // derived from itself.
782 bool MatchASTVisitor::classIsDerivedFrom(const CXXRecordDecl *Declaration,
783  const Matcher<NamedDecl> &Base,
784  BoundNodesTreeBuilder *Builder) {
785  if (!Declaration->hasDefinition())
786  return false;
787  for (const auto &It : Declaration->bases()) {
788  const Type *TypeNode = It.getType().getTypePtr();
789 
790  if (typeHasMatchingAlias(TypeNode, Base, Builder))
791  return true;
792 
793  // FIXME: Going to the primary template here isn't really correct, but
794  // unfortunately we accept a Decl matcher for the base class not a Type
795  // matcher, so it's the best thing we can do with our current interface.
796  CXXRecordDecl *ClassDecl = getAsCXXRecordDeclOrPrimaryTemplate(TypeNode);
797  if (!ClassDecl)
798  continue;
799  if (ClassDecl == Declaration) {
800  // This can happen for recursive template definitions; if the
801  // current declaration did not match, we can safely return false.
802  return false;
803  }
804  BoundNodesTreeBuilder Result(*Builder);
805  if (Base.matches(*ClassDecl, this, &Result)) {
806  *Builder = std::move(Result);
807  return true;
808  }
809  if (classIsDerivedFrom(ClassDecl, Base, Builder))
810  return true;
811  }
812  return false;
813 }
814 
815 bool MatchASTVisitor::TraverseDecl(Decl *DeclNode) {
816  if (!DeclNode) {
817  return true;
818  }
819  match(*DeclNode);
821 }
822 
823 bool MatchASTVisitor::TraverseStmt(Stmt *StmtNode) {
824  if (!StmtNode) {
825  return true;
826  }
827  match(*StmtNode);
829 }
830 
831 bool MatchASTVisitor::TraverseType(QualType TypeNode) {
832  match(TypeNode);
834 }
835 
836 bool MatchASTVisitor::TraverseTypeLoc(TypeLoc TypeLocNode) {
837  // The RecursiveASTVisitor only visits types if they're not within TypeLocs.
838  // We still want to find those types via matchers, so we match them here. Note
839  // that the TypeLocs are structurally a shadow-hierarchy to the expressed
840  // type, so we visit all involved parts of a compound type when matching on
841  // each TypeLoc.
842  match(TypeLocNode);
843  match(TypeLocNode.getType());
845 }
846 
847 bool MatchASTVisitor::TraverseNestedNameSpecifier(NestedNameSpecifier *NNS) {
848  match(*NNS);
850 }
851 
852 bool MatchASTVisitor::TraverseNestedNameSpecifierLoc(
853  NestedNameSpecifierLoc NNS) {
854  if (!NNS)
855  return true;
856 
857  match(NNS);
858 
859  // We only match the nested name specifier here (as opposed to traversing it)
860  // because the traversal is already done in the parallel "Loc"-hierarchy.
861  if (NNS.hasQualifier())
862  match(*NNS.getNestedNameSpecifier());
863  return
865 }
866 
867 class MatchASTConsumer : public ASTConsumer {
868 public:
869  MatchASTConsumer(MatchFinder *Finder,
870  MatchFinder::ParsingDoneTestCallback *ParsingDone)
871  : Finder(Finder), ParsingDone(ParsingDone) {}
872 
873 private:
874  void HandleTranslationUnit(ASTContext &Context) override {
875  if (ParsingDone != nullptr) {
876  ParsingDone->run();
877  }
878  Finder->matchAST(Context);
879  }
880 
881  MatchFinder *Finder;
882  MatchFinder::ParsingDoneTestCallback *ParsingDone;
883 };
884 
885 } // end namespace
886 } // end namespace internal
887 
890  : Nodes(Nodes), Context(Context),
891  SourceManager(&Context->getSourceManager()) {}
892 
895 
897  : Options(std::move(Options)), ParsingDone(nullptr) {}
898 
900 
902  MatchCallback *Action) {
903  Matchers.DeclOrStmt.emplace_back(NodeMatch, Action);
904  Matchers.AllCallbacks.insert(Action);
905 }
906 
907 void MatchFinder::addMatcher(const TypeMatcher &NodeMatch,
908  MatchCallback *Action) {
909  Matchers.Type.emplace_back(NodeMatch, Action);
910  Matchers.AllCallbacks.insert(Action);
911 }
912 
914  MatchCallback *Action) {
915  Matchers.DeclOrStmt.emplace_back(NodeMatch, Action);
916  Matchers.AllCallbacks.insert(Action);
917 }
918 
920  MatchCallback *Action) {
921  Matchers.NestedNameSpecifier.emplace_back(NodeMatch, Action);
922  Matchers.AllCallbacks.insert(Action);
923 }
924 
926  MatchCallback *Action) {
927  Matchers.NestedNameSpecifierLoc.emplace_back(NodeMatch, Action);
928  Matchers.AllCallbacks.insert(Action);
929 }
930 
932  MatchCallback *Action) {
933  Matchers.TypeLoc.emplace_back(NodeMatch, Action);
934  Matchers.AllCallbacks.insert(Action);
935 }
936 
937 bool MatchFinder::addDynamicMatcher(const internal::DynTypedMatcher &NodeMatch,
938  MatchCallback *Action) {
939  if (NodeMatch.canConvertTo<Decl>()) {
940  addMatcher(NodeMatch.convertTo<Decl>(), Action);
941  return true;
942  } else if (NodeMatch.canConvertTo<QualType>()) {
943  addMatcher(NodeMatch.convertTo<QualType>(), Action);
944  return true;
945  } else if (NodeMatch.canConvertTo<Stmt>()) {
946  addMatcher(NodeMatch.convertTo<Stmt>(), Action);
947  return true;
948  } else if (NodeMatch.canConvertTo<NestedNameSpecifier>()) {
949  addMatcher(NodeMatch.convertTo<NestedNameSpecifier>(), Action);
950  return true;
951  } else if (NodeMatch.canConvertTo<NestedNameSpecifierLoc>()) {
952  addMatcher(NodeMatch.convertTo<NestedNameSpecifierLoc>(), Action);
953  return true;
954  } else if (NodeMatch.canConvertTo<TypeLoc>()) {
955  addMatcher(NodeMatch.convertTo<TypeLoc>(), Action);
956  return true;
957  }
958  return false;
959 }
960 
961 std::unique_ptr<ASTConsumer> MatchFinder::newASTConsumer() {
962  return llvm::make_unique<internal::MatchASTConsumer>(this, ParsingDone);
963 }
964 
966  ASTContext &Context) {
967  internal::MatchASTVisitor Visitor(&Matchers, Options);
968  Visitor.set_active_ast_context(&Context);
969  Visitor.match(Node);
970 }
971 
973  internal::MatchASTVisitor Visitor(&Matchers, Options);
974  Visitor.set_active_ast_context(&Context);
975  Visitor.onStartOfTranslationUnit();
976  Visitor.TraverseDecl(Context.getTranslationUnitDecl());
977  Visitor.onEndOfTranslationUnit();
978 }
979 
981  MatchFinder::ParsingDoneTestCallback *NewParsingDone) {
982  ParsingDone = NewParsingDone;
983 }
984 
985 StringRef MatchFinder::MatchCallback::getID() const { return "<unknown>"; }
986 
987 } // end namespace ast_matchers
988 } // end namespace clang
Defines the clang::ASTContext interface.
const MatchFinder::MatchersByType * Matchers
A (possibly-)qualified type.
Definition: Type.h:598
MatchFinder::ParsingDoneTestCallback * ParsingDone
internal::Matcher< Decl > DeclarationMatcher
Types of matchers for the top-level classes in the AST class hierarchy.
Definition: ASTMatchers.h:123
const DynTypedMatcher *const Matcher
Called when parsing is finished. Intended for testing only.
MatchFinder(MatchFinderOptions Options=MatchFinderOptions())
BoundNodesTreeBuilder Nodes
bool TraverseDecl(Decl *D)
Recursively visit a declaration, by dispatching to Traverse*Decl() based on the argument's dynamic ty...
Base wrapper for a particular "section" of type source info.
Definition: TypeLoc.h:40
void match(const T &Node, ASTContext &Context)
Calls the registered callbacks on all matches on the given Node.
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:92
A C++ nested-name-specifier augmented with source location information.
const ASTMatchFinder::BindKind Bind
FrontendAction * Action
Definition: Tooling.cpp:201
ASTContext * ActiveASTContext
void addMatcher(const DeclarationMatcher &NodeMatch, MatchCallback *Action)
Adds a matcher to execute when running over the AST.
SmallVector< BoundNodes, 1 > match(MatcherT Matcher, const NodeT &Node, ASTContext &Context)
Returns the results of matching Matcher on Node.
internal::Matcher< Stmt > StatementMatcher
Definition: ASTMatchers.h:124
detail::InMemoryDirectory::const_iterator I
BoundNodesTreeBuilder ResultBindings
DynTypedMatcher::MatcherIDType MatcherID
ASTContext * Context
internal::Matcher< NestedNameSpecifierLoc > NestedNameSpecifierLocMatcher
Definition: ASTMatchers.h:128
virtual StringRef getID() const
An id used to group the matchers.
int * Depth
friend class ASTContext
Definition: Type.h:4178
MatchFinder::MatchCallback * Callback
TranslationUnitDecl * getTranslationUnitDecl() const
Definition: ASTContext.h:886
llvm::DenseMap< ast_type_traits::ASTNodeKind, std::vector< unsigned short > > MatcherFiltersMap
Filtered list of matcher indices for each matcher kind.
void registerTestCallbackAfterParsing(ParsingDoneTestCallback *ParsingDone)
Registers a callback to notify the end of parsing.
MatchResult(const BoundNodes &Nodes, clang::ASTContext *Context)
The result type of a method or function.
std::unique_ptr< clang::ASTConsumer > newASTConsumer()
Creates a clang ASTConsumer that finds all matches.
#define USHRT_MAX
Definition: limits.h:71
The l-value was considered opaque, so the alignment was determined from a type.
Maps string IDs to AST nodes matched by parts of a matcher.
Definition: ASTMatchers.h:68
const MatchFinder::MatchFinderOptions & Options
ASTMatchFinder *const Finder
bool ResultOfMatch
Kind
const TemplateArgument * iterator
Definition: Type.h:4233
bool TraverseTypeLoc(TypeLoc TL)
Recursively visit a type with location, by dispatching to Traverse*TypeLoc() based on the argument ty...
bool TraverseNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS)
Recursively visit a C++ nested-name-specifier with location information.
const ASTMatchFinder::TraversalKind Traversal
Represents a C++ nested name specifier, such as "\::std::vector<int>::".
internal::Matcher< TypeLoc > TypeLocMatcher
Definition: ASTMatchers.h:126
void matchAST(ASTContext &Context)
Finds all matches in the given AST.
bool Matches
bool TraverseStmt(Stmt *S, DataRecursionQueue *Queue=nullptr)
Recursively visit a statement or expression, by dispatching to Traverse*() based on the argument's dy...
bool operator<(DeclarationName LHS, DeclarationName RHS)
Ordering on two declaration names.
bool TraverseType(QualType T)
Recursively visit a type, by dispatching to Traverse*Type() based on the argument's getTypeClass() pr...
static DynTypedNode create(const T &Node)
Creates a DynTypedNode from Node.
BoundNodesTreeBuilder BoundNodes
ast_type_traits::DynTypedNode Node
internal::Matcher< NestedNameSpecifier > NestedNameSpecifierMatcher
Definition: ASTMatchers.h:127
int CurrentDepth
detail::InMemoryDirectory::const_iterator E
const int MaxDepth
A dynamically typed AST node container.
bool TraverseNestedNameSpecifier(NestedNameSpecifier *NNS)
Recursively visit a C++ nested-name-specifier.
MemoizationMap ResultCache
internal::Matcher< QualType > TypeMatcher
Definition: ASTMatchers.h:125
BoundNodesTreeBuilder *const Builder
#define INT_MAX
Definition: limits.h:62
llvm::DenseMap< const Type *, std::set< const TypedefNameDecl * > > TypeAliases
TemplateSpecializationType(TemplateName T, ArrayRef< TemplateArgument > Args, QualType Canon, QualType Aliased)
This class handles loading and caching of source files into memory.
bool addDynamicMatcher(const internal::DynTypedMatcher &NodeMatch, MatchCallback *Action)
Adds a matcher to execute when running over the AST.
llvm::StringMap< llvm::TimeRecord > TimeByBucket
Bucket to record map.
llvm::TimeRecord * Bucket