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
44 #include "clang/ASTMatchers/ASTMatchers.h"
45 #include "llvm/ADT/SmallPtrSet.h"
46 #include "llvm/ADT/StringMap.h"
47 #include "llvm/Support/Timer.h"
48
49 namespace clang {
50
51 namespace ast_matchers {
52
53 /// \brief A class to allow finding matches over the Clang AST.
54 ///
55 /// After creation, you can add multiple matchers to the MatchFinder via
56 /// calls to addMatcher(...).
57 ///
58 /// Once all matchers are added, newASTConsumer() returns an ASTConsumer
59 /// that will trigger the callbacks specified via addMatcher(...) when a match
60 /// is found.
61 ///
62 /// The order of matches is guaranteed to be equivalent to doing a pre-order
63 /// traversal on the AST, and applying the matchers in the order in which they
64 /// were added to the MatchFinder.
65 ///
66 /// See ASTMatchers.h for more information about how to create matchers.
67 ///
68 /// Not intended to be subclassed.
69 class MatchFinder {
70 public:
71 /// \brief Contains all information for a given match.
72 ///
73 /// Every time a match is found, the MatchFinder will invoke the registered
74 /// MatchCallback with a MatchResult containing information about the match.
75 struct MatchResult {
76 MatchResult(const BoundNodes &Nodes, clang::ASTContext *Context);
77
78 /// \brief Contains the nodes bound on the current match.
79 ///
80 /// This allows user code to easily extract matched AST nodes.
81 const BoundNodes Nodes;
82
83 /// \brief Utilities for interpreting the matched AST structures.
84 /// @{
85 clang::ASTContext * const Context;
86 clang::SourceManager * const SourceManager;
87 /// @}
88 };
89
90 /// \brief Called when the Match registered for it was successfully found
91 /// in the AST.
92 class MatchCallback {
93 public:
94 virtual ~MatchCallback();
95
96 /// \brief Called on every match by the \c MatchFinder.
97 virtual void run(const MatchResult &Result) = 0;
98
99 /// \brief Called at the start of each translation unit.
100 ///
101 /// Optionally override to do per translation unit tasks.
onStartOfTranslationUnit()102 virtual void onStartOfTranslationUnit() {}
103
104 /// \brief Called at the end of each translation unit.
105 ///
106 /// Optionally override to do per translation unit tasks.
onEndOfTranslationUnit()107 virtual void onEndOfTranslationUnit() {}
108
109 /// \brief An id used to group the matchers.
110 ///
111 /// This id is used, for example, for the profiling output.
112 /// It defaults to "<unknown>".
113 virtual StringRef getID() const;
114 };
115
116 /// \brief Called when parsing is finished. Intended for testing only.
117 class ParsingDoneTestCallback {
118 public:
119 virtual ~ParsingDoneTestCallback();
120 virtual void run() = 0;
121 };
122
123 struct MatchFinderOptions {
124 struct Profiling {
ProfilingMatchFinderOptions::Profiling125 Profiling(llvm::StringMap<llvm::TimeRecord> &Records)
126 : Records(Records) {}
127
128 /// \brief Per bucket timing information.
129 llvm::StringMap<llvm::TimeRecord> &Records;
130 };
131
132 /// \brief Enables per-check timers.
133 ///
134 /// It prints a report after match.
135 llvm::Optional<Profiling> CheckProfiling;
136 };
137
138 MatchFinder(MatchFinderOptions Options = MatchFinderOptions());
139 ~MatchFinder();
140
141 /// \brief Adds a matcher to execute when running over the AST.
142 ///
143 /// Calls 'Action' with the BoundNodes on every match.
144 /// Adding more than one 'NodeMatch' allows finding different matches in a
145 /// single pass over the AST.
146 ///
147 /// Does not take ownership of 'Action'.
148 /// @{
149 void addMatcher(const DeclarationMatcher &NodeMatch,
150 MatchCallback *Action);
151 void addMatcher(const TypeMatcher &NodeMatch,
152 MatchCallback *Action);
153 void addMatcher(const StatementMatcher &NodeMatch,
154 MatchCallback *Action);
155 void addMatcher(const NestedNameSpecifierMatcher &NodeMatch,
156 MatchCallback *Action);
157 void addMatcher(const NestedNameSpecifierLocMatcher &NodeMatch,
158 MatchCallback *Action);
159 void addMatcher(const TypeLocMatcher &NodeMatch,
160 MatchCallback *Action);
161 /// @}
162
163 /// \brief Adds a matcher to execute when running over the AST.
164 ///
165 /// This is similar to \c addMatcher(), but it uses the dynamic interface. It
166 /// is more flexible, but the lost type information enables a caller to pass
167 /// a matcher that cannot match anything.
168 ///
169 /// \returns \c true if the matcher is a valid top-level matcher, \c false
170 /// otherwise.
171 bool addDynamicMatcher(const internal::DynTypedMatcher &NodeMatch,
172 MatchCallback *Action);
173
174 /// \brief Creates a clang ASTConsumer that finds all matches.
175 std::unique_ptr<clang::ASTConsumer> newASTConsumer();
176
177 /// \brief Calls the registered callbacks on all matches on the given \p Node.
178 ///
179 /// Note that there can be multiple matches on a single node, for
180 /// example when using decl(forEachDescendant(stmt())).
181 ///
182 /// @{
match(const T & Node,ASTContext & Context)183 template <typename T> void match(const T &Node, ASTContext &Context) {
184 match(clang::ast_type_traits::DynTypedNode::create(Node), Context);
185 }
186 void match(const clang::ast_type_traits::DynTypedNode &Node,
187 ASTContext &Context);
188 /// @}
189
190 /// \brief Finds all matches in the given AST.
191 void matchAST(ASTContext &Context);
192
193 /// \brief Registers a callback to notify the end of parsing.
194 ///
195 /// The provided closure is called after parsing is done, before the AST is
196 /// traversed. Useful for benchmarking.
197 /// Each call to FindAll(...) will call the closure once.
198 void registerTestCallbackAfterParsing(ParsingDoneTestCallback *ParsingDone);
199
200 /// \brief For each \c Matcher<> a \c MatchCallback that will be called
201 /// when it matches.
202 struct MatchersByType {
203 std::vector<std::pair<internal::DynTypedMatcher, MatchCallback *>>
204 DeclOrStmt;
205 std::vector<std::pair<TypeMatcher, MatchCallback *>> Type;
206 std::vector<std::pair<NestedNameSpecifierMatcher, MatchCallback *>>
207 NestedNameSpecifier;
208 std::vector<std::pair<NestedNameSpecifierLocMatcher, MatchCallback *>>
209 NestedNameSpecifierLoc;
210 std::vector<std::pair<TypeLocMatcher, MatchCallback *>> TypeLoc;
211 /// \brief All the callbacks in one container to simplify iteration.
212 llvm::SmallPtrSet<MatchCallback *, 16> AllCallbacks;
213 };
214
215 private:
216 MatchersByType Matchers;
217
218 MatchFinderOptions Options;
219
220 /// \brief Called when parsing is done.
221 ParsingDoneTestCallback *ParsingDone;
222 };
223
224 /// \brief Returns the results of matching \p Matcher on \p Node.
225 ///
226 /// Collects the \c BoundNodes of all callback invocations when matching
227 /// \p Matcher on \p Node and returns the collected results.
228 ///
229 /// Multiple results occur when using matchers like \c forEachDescendant,
230 /// which generate a result for each sub-match.
231 ///
232 /// \see selectFirst
233 /// @{
234 template <typename MatcherT, typename NodeT>
235 SmallVector<BoundNodes, 1>
236 match(MatcherT Matcher, const NodeT &Node, ASTContext &Context);
237
238 template <typename MatcherT>
239 SmallVector<BoundNodes, 1>
240 match(MatcherT Matcher, const ast_type_traits::DynTypedNode &Node,
241 ASTContext &Context);
242 /// @}
243
244 /// \brief Returns the results of matching \p Matcher on the translation unit of
245 /// \p Context and collects the \c BoundNodes of all callback invocations.
246 template <typename MatcherT>
247 SmallVector<BoundNodes, 1> match(MatcherT Matcher, ASTContext &Context);
248
249 /// \brief Returns the first result of type \c NodeT bound to \p BoundTo.
250 ///
251 /// Returns \c NULL if there is no match, or if the matching node cannot be
252 /// casted to \c NodeT.
253 ///
254 /// This is useful in combanation with \c match():
255 /// \code
256 /// const Decl *D = selectFirst<Decl>("id", match(Matcher.bind("id"),
257 /// Node, Context));
258 /// \endcode
259 template <typename NodeT>
260 const NodeT *
selectFirst(StringRef BoundTo,const SmallVectorImpl<BoundNodes> & Results)261 selectFirst(StringRef BoundTo, const SmallVectorImpl<BoundNodes> &Results) {
262 for (const BoundNodes &N : Results) {
263 if (const NodeT *Node = N.getNodeAs<NodeT>(BoundTo))
264 return Node;
265 }
266 return nullptr;
267 }
268
269 namespace internal {
270 class CollectMatchesCallback : public MatchFinder::MatchCallback {
271 public:
run(const MatchFinder::MatchResult & Result)272 void run(const MatchFinder::MatchResult &Result) override {
273 Nodes.push_back(Result.Nodes);
274 }
275 SmallVector<BoundNodes, 1> Nodes;
276 };
277 }
278
279 template <typename MatcherT>
280 SmallVector<BoundNodes, 1>
match(MatcherT Matcher,const ast_type_traits::DynTypedNode & Node,ASTContext & Context)281 match(MatcherT Matcher, const ast_type_traits::DynTypedNode &Node,
282 ASTContext &Context) {
283 internal::CollectMatchesCallback Callback;
284 MatchFinder Finder;
285 Finder.addMatcher(Matcher, &Callback);
286 Finder.match(Node, Context);
287 return std::move(Callback.Nodes);
288 }
289
290 template <typename MatcherT, typename NodeT>
291 SmallVector<BoundNodes, 1>
match(MatcherT Matcher,const NodeT & Node,ASTContext & Context)292 match(MatcherT Matcher, const NodeT &Node, ASTContext &Context) {
293 return match(Matcher, ast_type_traits::DynTypedNode::create(Node), Context);
294 }
295
296 template <typename MatcherT>
297 SmallVector<BoundNodes, 1>
match(MatcherT Matcher,ASTContext & Context)298 match(MatcherT Matcher, ASTContext &Context) {
299 internal::CollectMatchesCallback Callback;
300 MatchFinder Finder;
301 Finder.addMatcher(Matcher, &Callback);
302 Finder.matchAST(Context);
303 return std::move(Callback.Nodes);
304 }
305
306 } // end namespace ast_matchers
307 } // end namespace clang
308
309 #endif
310