clang  3.7.0
ASTMatchFinder.h
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1 //===--- ASTMatchFinder.h - Structural query framework ----------*- C++ -*-===//
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 // Provides a way to construct an ASTConsumer that runs given matchers
11 // over the AST and invokes a given callback on every match.
12 //
13 // The general idea is to construct a matcher expression that describes a
14 // subtree match on the AST. Next, a callback that is executed every time the
15 // expression matches is registered, and the matcher is run over the AST of
16 // some code. Matched subexpressions can be bound to string IDs and easily
17 // be accessed from the registered callback. The callback can than use the
18 // AST nodes that the subexpressions matched on to output information about
19 // the match or construct changes that can be applied to the code.
20 //
21 // Example:
22 // class HandleMatch : public MatchFinder::MatchCallback {
23 // public:
24 // virtual void Run(const MatchFinder::MatchResult &Result) {
25 // const CXXRecordDecl *Class =
26 // Result.Nodes.GetDeclAs<CXXRecordDecl>("id");
27 // ...
28 // }
29 // };
30 //
31 // int main(int argc, char **argv) {
32 // ClangTool Tool(argc, argv);
33 // MatchFinder finder;
34 // finder.AddMatcher(Id("id", record(hasName("::a_namespace::AClass"))),
35 // new HandleMatch);
36 // return Tool.Run(newFrontendActionFactory(&finder));
37 // }
38 //
39 //===----------------------------------------------------------------------===//
40 
41 #ifndef LLVM_CLANG_ASTMATCHERS_ASTMATCHFINDER_H
42 #define LLVM_CLANG_ASTMATCHERS_ASTMATCHFINDER_H
43 
45 #include "llvm/ADT/StringMap.h"
46 #include "llvm/Support/Timer.h"
47 
48 namespace clang {
49 
50 namespace ast_matchers {
51 
52 /// \brief A class to allow finding matches over the Clang AST.
53 ///
54 /// After creation, you can add multiple matchers to the MatchFinder via
55 /// calls to addMatcher(...).
56 ///
57 /// Once all matchers are added, newASTConsumer() returns an ASTConsumer
58 /// that will trigger the callbacks specified via addMatcher(...) when a match
59 /// is found.
60 ///
61 /// The order of matches is guaranteed to be equivalent to doing a pre-order
62 /// traversal on the AST, and applying the matchers in the order in which they
63 /// were added to the MatchFinder.
64 ///
65 /// See ASTMatchers.h for more information about how to create matchers.
66 ///
67 /// Not intended to be subclassed.
68 class MatchFinder {
69 public:
70  /// \brief Contains all information for a given match.
71  ///
72  /// Every time a match is found, the MatchFinder will invoke the registered
73  /// MatchCallback with a MatchResult containing information about the match.
74  struct MatchResult {
76 
77  /// \brief Contains the nodes bound on the current match.
78  ///
79  /// This allows user code to easily extract matched AST nodes.
81 
82  /// \brief Utilities for interpreting the matched AST structures.
83  /// @{
86  /// @}
87  };
88 
89  /// \brief Called when the Match registered for it was successfully found
90  /// in the AST.
91  class MatchCallback {
92  public:
93  virtual ~MatchCallback();
94 
95  /// \brief Called on every match by the \c MatchFinder.
96  virtual void run(const MatchResult &Result) = 0;
97 
98  /// \brief Called at the start of each translation unit.
99  ///
100  /// Optionally override to do per translation unit tasks.
101  virtual void onStartOfTranslationUnit() {}
102 
103  /// \brief Called at the end of each translation unit.
104  ///
105  /// Optionally override to do per translation unit tasks.
106  virtual void onEndOfTranslationUnit() {}
107 
108  /// \brief An id used to group the matchers.
109  ///
110  /// This id is used, for example, for the profiling output.
111  /// It defaults to "<unknown>".
112  virtual StringRef getID() const;
113  };
114 
115  /// \brief Called when parsing is finished. Intended for testing only.
117  public:
118  virtual ~ParsingDoneTestCallback();
119  virtual void run() = 0;
120  };
121 
123  struct Profiling {
124  Profiling(llvm::StringMap<llvm::TimeRecord> &Records)
125  : Records(Records) {}
126 
127  /// \brief Per bucket timing information.
128  llvm::StringMap<llvm::TimeRecord> &Records;
129  };
130 
131  /// \brief Enables per-check timers.
132  ///
133  /// It prints a report after match.
135  };
136 
138  ~MatchFinder();
139 
140  /// \brief Adds a matcher to execute when running over the AST.
141  ///
142  /// Calls 'Action' with the BoundNodes on every match.
143  /// Adding more than one 'NodeMatch' allows finding different matches in a
144  /// single pass over the AST.
145  ///
146  /// Does not take ownership of 'Action'.
147  /// @{
148  void addMatcher(const DeclarationMatcher &NodeMatch,
150  void addMatcher(const TypeMatcher &NodeMatch,
152  void addMatcher(const StatementMatcher &NodeMatch,
154  void addMatcher(const NestedNameSpecifierMatcher &NodeMatch,
156  void addMatcher(const NestedNameSpecifierLocMatcher &NodeMatch,
158  void addMatcher(const TypeLocMatcher &NodeMatch,
160  /// @}
161 
162  /// \brief Adds a matcher to execute when running over the AST.
163  ///
164  /// This is similar to \c addMatcher(), but it uses the dynamic interface. It
165  /// is more flexible, but the lost type information enables a caller to pass
166  /// a matcher that cannot match anything.
167  ///
168  /// \returns \c true if the matcher is a valid top-level matcher, \c false
169  /// otherwise.
170  bool addDynamicMatcher(const internal::DynTypedMatcher &NodeMatch,
172 
173  /// \brief Creates a clang ASTConsumer that finds all matches.
174  std::unique_ptr<clang::ASTConsumer> newASTConsumer();
175 
176  /// \brief Calls the registered callbacks on all matches on the given \p Node.
177  ///
178  /// Note that there can be multiple matches on a single node, for
179  /// example when using decl(forEachDescendant(stmt())).
180  ///
181  /// @{
182  template <typename T> void match(const T &Node, ASTContext &Context) {
184  }
187  /// @}
188 
189  /// \brief Finds all matches in the given AST.
190  void matchAST(ASTContext &Context);
191 
192  /// \brief Registers a callback to notify the end of parsing.
193  ///
194  /// The provided closure is called after parsing is done, before the AST is
195  /// traversed. Useful for benchmarking.
196  /// Each call to FindAll(...) will call the closure once.
197  void registerTestCallbackAfterParsing(ParsingDoneTestCallback *ParsingDone);
198 
199  /// \brief For each \c Matcher<> a \c MatchCallback that will be called
200  /// when it matches.
201  struct MatchersByType {
202  std::vector<std::pair<internal::DynTypedMatcher, MatchCallback *>>
204  std::vector<std::pair<TypeMatcher, MatchCallback *>> Type;
205  std::vector<std::pair<NestedNameSpecifierMatcher, MatchCallback *>>
207  std::vector<std::pair<NestedNameSpecifierLocMatcher, MatchCallback *>>
209  std::vector<std::pair<TypeLocMatcher, MatchCallback *>> TypeLoc;
210  /// \brief All the callbacks in one container to simplify iteration.
211  std::vector<MatchCallback *> AllCallbacks;
212  };
213 
214 private:
215  MatchersByType Matchers;
216 
217  MatchFinderOptions Options;
218 
219  /// \brief Called when parsing is done.
220  ParsingDoneTestCallback *ParsingDone;
221 };
222 
223 /// \brief Returns the results of matching \p Matcher on \p Node.
224 ///
225 /// Collects the \c BoundNodes of all callback invocations when matching
226 /// \p Matcher on \p Node and returns the collected results.
227 ///
228 /// Multiple results occur when using matchers like \c forEachDescendant,
229 /// which generate a result for each sub-match.
230 ///
231 /// \see selectFirst
232 /// @{
233 template <typename MatcherT, typename NodeT>
235 match(MatcherT Matcher, const NodeT &Node, ASTContext &Context);
236 
237 template <typename MatcherT>
241 /// @}
242 
243 /// \brief Returns the first result of type \c NodeT bound to \p BoundTo.
244 ///
245 /// Returns \c NULL if there is no match, or if the matching node cannot be
246 /// casted to \c NodeT.
247 ///
248 /// This is useful in combanation with \c match():
249 /// \code
250 /// const Decl *D = selectFirst<Decl>("id", match(Matcher.bind("id"),
251 /// Node, Context));
252 /// \endcode
253 template <typename NodeT>
254 const NodeT *
255 selectFirst(StringRef BoundTo, const SmallVectorImpl<BoundNodes> &Results) {
256  for (const BoundNodes &N : Results) {
257  if (const NodeT *Node = N.getNodeAs<NodeT>(BoundTo))
258  return Node;
259  }
260  return nullptr;
261 }
262 
263 namespace internal {
265 public:
266  void run(const MatchFinder::MatchResult &Result) override {
267  Nodes.push_back(Result.Nodes);
268  }
270 };
271 }
272 
273 template <typename MatcherT>
276  ASTContext &Context) {
279  Finder.addMatcher(Matcher, &Callback);
280  Finder.match(Node, Context);
281  return std::move(Callback.Nodes);
282 }
283 
284 template <typename MatcherT, typename NodeT>
286 match(MatcherT Matcher, const NodeT &Node, ASTContext &Context) {
287  return match(Matcher, ast_type_traits::DynTypedNode::create(Node), Context);
288 }
289 
290 } // end namespace ast_matchers
291 } // end namespace clang
292 
293 #endif
A class to allow finding matches over the Clang AST.
const NodeT * selectFirst(StringRef BoundTo, const SmallVectorImpl< BoundNodes > &Results)
Returns the first result of type NodeT bound to BoundTo.
llvm::StringMap< llvm::TimeRecord > & Records
Per bucket timing information.
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())
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:89
FrontendAction * Action
Definition: Tooling.cpp:168
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
ASTContext * Context
internal::Matcher< NestedNameSpecifierLoc > NestedNameSpecifierLocMatcher
Definition: ASTMatchers.h:128
virtual StringRef getID() const
An id used to group the matchers.
MatchFinder::MatchCallback * Callback
Contains all information for a given match.
void registerTestCallbackAfterParsing(ParsingDoneTestCallback *ParsingDone)
Registers a callback to notify the end of parsing.
MatchResult(const BoundNodes &Nodes, clang::ASTContext *Context)
Profiling(llvm::StringMap< llvm::TimeRecord > &Records)
The result type of a method or function.
std::unique_ptr< clang::ASTConsumer > newASTConsumer()
Creates a clang ASTConsumer that finds all matches.
Maps string IDs to AST nodes matched by parts of a matcher.
Definition: ASTMatchers.h:68
ASTMatchFinder *const Finder
virtual void run(const MatchResult &Result)=0
Called on every match by the MatchFinder.
clang::ASTContext *const Context
Utilities for interpreting the matched AST structures.
internal::Matcher< TypeLoc > TypeLocMatcher
Definition: ASTMatchers.h:126
void matchAST(ASTContext &Context)
Finds all matches in the given AST.
std::vector< std::pair< NestedNameSpecifierLocMatcher, MatchCallback * > > NestedNameSpecifierLoc
std::vector< std::pair< internal::DynTypedMatcher, MatchCallback * > > DeclOrStmt
llvm::Optional< Profiling > CheckProfiling
Enables per-check timers.
static DynTypedNode create(const T &Node)
Creates a DynTypedNode from Node.
std::vector< std::pair< NestedNameSpecifierMatcher, MatchCallback * > > NestedNameSpecifier
std::vector< std::pair< TypeMatcher, MatchCallback * > > Type
virtual void onEndOfTranslationUnit()
Called at the end of each translation unit.
const BoundNodes Nodes
Contains the nodes bound on the current match.
ast_type_traits::DynTypedNode Node
For each Matcher<> a MatchCallback that will be called when it matches.
internal::Matcher< NestedNameSpecifier > NestedNameSpecifierMatcher
Definition: ASTMatchers.h:127
A dynamically typed AST node container.
std::vector< std::pair< TypeLocMatcher, MatchCallback * > > TypeLoc
internal::Matcher< QualType > TypeMatcher
Definition: ASTMatchers.h:125
std::vector< MatchCallback * > AllCallbacks
All the callbacks in one container to simplify iteration.
void run(const MatchFinder::MatchResult &Result) override
Called on every match by the MatchFinder.
Called when the Match registered for it was successfully found in the AST.
clang::SourceManager *const SourceManager
virtual void onStartOfTranslationUnit()
Called at the start of each translation unit.
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.