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ASTMatchFinder.h
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1 //===--- ASTMatchFinder.h - Structural query framework ----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Provides a way to construct an ASTConsumer that runs given matchers
10 // over the AST and invokes a given callback on every match.
11 //
12 // The general idea is to construct a matcher expression that describes a
13 // subtree match on the AST. Next, a callback that is executed every time the
14 // expression matches is registered, and the matcher is run over the AST of
15 // some code. Matched subexpressions can be bound to string IDs and easily
16 // be accessed from the registered callback. The callback can than use the
17 // AST nodes that the subexpressions matched on to output information about
18 // the match or construct changes that can be applied to the code.
19 //
20 // Example:
21 // class HandleMatch : public MatchFinder::MatchCallback {
22 // public:
23 // virtual void Run(const MatchFinder::MatchResult &Result) {
24 // const CXXRecordDecl *Class =
25 // Result.Nodes.GetDeclAs<CXXRecordDecl>("id");
26 // ...
27 // }
28 // };
29 //
30 // int main(int argc, char **argv) {
31 // ClangTool Tool(argc, argv);
32 // MatchFinder finder;
33 // finder.AddMatcher(Id("id", record(hasName("::a_namespace::AClass"))),
34 // new HandleMatch);
35 // return Tool.Run(newFrontendActionFactory(&finder));
36 // }
37 //
38 //===----------------------------------------------------------------------===//
39 
40 #ifndef LLVM_CLANG_ASTMATCHERS_ASTMATCHFINDER_H
41 #define LLVM_CLANG_ASTMATCHERS_ASTMATCHFINDER_H
42 
44 #include "llvm/ADT/SmallPtrSet.h"
45 #include "llvm/ADT/StringMap.h"
46 #include "llvm/Support/Timer.h"
47 
48 namespace clang {
49 
50 namespace ast_matchers {
51 
52 /// 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  /// 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  /// Contains the nodes bound on the current match.
78  ///
79  /// This allows user code to easily extract matched AST nodes.
81 
82  /// Utilities for interpreting the matched AST structures.
83  /// @{
86  /// @}
87  };
88 
89  /// Called when the Match registered for it was successfully found
90  /// in the AST.
91  class MatchCallback {
92  public:
93  virtual ~MatchCallback();
94 
95  /// Called on every match by the \c MatchFinder.
96  virtual void run(const MatchResult &Result) = 0;
97 
98  /// Called at the start of each translation unit.
99  ///
100  /// Optionally override to do per translation unit tasks.
101  virtual void onStartOfTranslationUnit() {}
102 
103  /// Called at the end of each translation unit.
104  ///
105  /// Optionally override to do per translation unit tasks.
106  virtual void onEndOfTranslationUnit() {}
107 
108  /// 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  /// 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  /// Per bucket timing information.
128  llvm::StringMap<llvm::TimeRecord> &Records;
129  };
130 
131  /// Enables per-check timers.
132  ///
133  /// It prints a report after match.
135  };
136 
138  ~MatchFinder();
139 
140  /// 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,
149  MatchCallback *Action);
150  void addMatcher(const TypeMatcher &NodeMatch,
151  MatchCallback *Action);
152  void addMatcher(const StatementMatcher &NodeMatch,
153  MatchCallback *Action);
154  void addMatcher(const NestedNameSpecifierMatcher &NodeMatch,
155  MatchCallback *Action);
156  void addMatcher(const NestedNameSpecifierLocMatcher &NodeMatch,
157  MatchCallback *Action);
158  void addMatcher(const TypeLocMatcher &NodeMatch,
159  MatchCallback *Action);
160  void addMatcher(const CXXCtorInitializerMatcher &NodeMatch,
161  MatchCallback *Action);
162  /// @}
163 
164  /// Adds a matcher to execute when running over the AST.
165  ///
166  /// This is similar to \c addMatcher(), but it uses the dynamic interface. It
167  /// is more flexible, but the lost type information enables a caller to pass
168  /// a matcher that cannot match anything.
169  ///
170  /// \returns \c true if the matcher is a valid top-level matcher, \c false
171  /// otherwise.
172  bool addDynamicMatcher(const internal::DynTypedMatcher &NodeMatch,
173  MatchCallback *Action);
174 
175  /// Creates a clang ASTConsumer that finds all matches.
176  std::unique_ptr<clang::ASTConsumer> newASTConsumer();
177 
178  /// Calls the registered callbacks on all matches on the given \p Node.
179  ///
180  /// Note that there can be multiple matches on a single node, for
181  /// example when using decl(forEachDescendant(stmt())).
182  ///
183  /// @{
184  template <typename T> void match(const T &Node, ASTContext &Context) {
186  }
189  /// @}
190 
191  /// Finds all matches in the given AST.
192  void matchAST(ASTContext &Context);
193 
194  /// Registers a callback to notify the end of parsing.
195  ///
196  /// The provided closure is called after parsing is done, before the AST is
197  /// traversed. Useful for benchmarking.
198  /// Each call to FindAll(...) will call the closure once.
200 
201  /// For each \c Matcher<> a \c MatchCallback that will be called
202  /// when it matches.
203  struct MatchersByType {
204  std::vector<std::pair<internal::DynTypedMatcher, MatchCallback *>>
206  std::vector<std::pair<TypeMatcher, MatchCallback *>> Type;
207  std::vector<std::pair<NestedNameSpecifierMatcher, MatchCallback *>>
209  std::vector<std::pair<NestedNameSpecifierLocMatcher, MatchCallback *>>
211  std::vector<std::pair<TypeLocMatcher, MatchCallback *>> TypeLoc;
212  std::vector<std::pair<CXXCtorInitializerMatcher, MatchCallback *>> CtorInit;
213  /// All the callbacks in one container to simplify iteration.
214  llvm::SmallPtrSet<MatchCallback *, 16> AllCallbacks;
215  };
216 
217 private:
218  MatchersByType Matchers;
219 
220  MatchFinderOptions Options;
221 
222  /// Called when parsing is done.
223  ParsingDoneTestCallback *ParsingDone;
224 };
225 
226 /// Returns the results of matching \p Matcher on \p Node.
227 ///
228 /// Collects the \c BoundNodes of all callback invocations when matching
229 /// \p Matcher on \p Node and returns the collected results.
230 ///
231 /// Multiple results occur when using matchers like \c forEachDescendant,
232 /// which generate a result for each sub-match.
233 ///
234 /// If you want to find all matches on the sub-tree rooted at \c Node (rather
235 /// than only the matches on \c Node itself), surround the \c Matcher with a
236 /// \c findAll().
237 ///
238 /// \see selectFirst
239 /// @{
240 template <typename MatcherT, typename NodeT>
242 match(MatcherT Matcher, const NodeT &Node, ASTContext &Context);
243 
244 template <typename MatcherT>
246 match(MatcherT Matcher, const ast_type_traits::DynTypedNode &Node,
248 /// @}
249 
250 /// Returns the results of matching \p Matcher on the translation unit of
251 /// \p Context and collects the \c BoundNodes of all callback invocations.
252 template <typename MatcherT>
254 
255 /// Returns the first result of type \c NodeT bound to \p BoundTo.
256 ///
257 /// Returns \c NULL if there is no match, or if the matching node cannot be
258 /// casted to \c NodeT.
259 ///
260 /// This is useful in combanation with \c match():
261 /// \code
262 /// const Decl *D = selectFirst<Decl>("id", match(Matcher.bind("id"),
263 /// Node, Context));
264 /// \endcode
265 template <typename NodeT>
266 const NodeT *
267 selectFirst(StringRef BoundTo, const SmallVectorImpl<BoundNodes> &Results) {
268  for (const BoundNodes &N : Results) {
269  if (const NodeT *Node = N.getNodeAs<NodeT>(BoundTo))
270  return Node;
271  }
272  return nullptr;
273 }
274 
275 namespace internal {
277 public:
278  void run(const MatchFinder::MatchResult &Result) override {
279  Nodes.push_back(Result.Nodes);
280  }
282 };
283 }
284 
285 template <typename MatcherT>
287 match(MatcherT Matcher, const ast_type_traits::DynTypedNode &Node,
288  ASTContext &Context) {
290  MatchFinder Finder;
291  Finder.addMatcher(Matcher, &Callback);
292  Finder.match(Node, Context);
293  return std::move(Callback.Nodes);
294 }
295 
296 template <typename MatcherT, typename NodeT>
298 match(MatcherT Matcher, const NodeT &Node, ASTContext &Context) {
299  return match(Matcher, ast_type_traits::DynTypedNode::create(Node), Context);
300 }
301 
302 template <typename MatcherT>
304 match(MatcherT Matcher, ASTContext &Context) {
306  MatchFinder Finder;
307  Finder.addMatcher(Matcher, &Callback);
308  Finder.matchAST(Context);
309  return std::move(Callback.Nodes);
310 }
311 
312 } // end namespace ast_matchers
313 } // end namespace clang
314 
315 #endif
A class to allow finding matches over the Clang AST.
internal::Matcher< NestedNameSpecifier > NestedNameSpecifierMatcher
Definition: ASTMatchers.h:141
const NodeT * selectFirst(StringRef BoundTo, const SmallVectorImpl< BoundNodes > &Results)
Returns the first result of type NodeT bound to BoundTo.
internal::Matcher< Stmt > StatementMatcher
Definition: ASTMatchers.h:138
llvm::StringMap< llvm::TimeRecord > & Records
Per bucket timing information.
llvm::SmallPtrSet< MatchCallback *, 16 > AllCallbacks
All the callbacks in one container to simplify iteration.
Called when parsing is finished. Intended for testing only.
MatchFinder(MatchFinderOptions Options=MatchFinderOptions())
internal::Matcher< QualType > TypeMatcher
Definition: ASTMatchers.h:139
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:160
void addMatcher(const DeclarationMatcher &NodeMatch, MatchCallback *Action)
Adds a matcher to execute when running over the AST.
std::vector< std::pair< CXXCtorInitializerMatcher, MatchCallback * > > CtorInit
StencilPart run(MatchConsumer< std::string > C)
Wraps a MatchConsumer in a StencilPart, so that it can be used in a Stencil.
Definition: Stencil.cpp:314
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)
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:103
clang::ASTContext *const Context
Utilities for interpreting the matched AST structures.
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.
Dataflow Directional Tag Classes.
internal::Matcher< CXXCtorInitializer > CXXCtorInitializerMatcher
Definition: ASTMatchers.h:143
A dynamically typed AST node container.
std::vector< std::pair< TypeLocMatcher, MatchCallback * > > TypeLoc
internal::Matcher< NestedNameSpecifierLoc > NestedNameSpecifierLocMatcher
Definition: ASTMatchers.h:142
internal::Matcher< TypeLoc > TypeLocMatcher
Definition: ASTMatchers.h:140
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.
internal::Matcher< Decl > DeclarationMatcher
Types of matchers for the top-level classes in the AST class hierarchy.
Definition: ASTMatchers.h:137
bool addDynamicMatcher(const internal::DynTypedMatcher &NodeMatch, MatchCallback *Action)
Adds a matcher to execute when running over the AST.