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
43#include "clang/ASTMatchers/ASTMatchers.h"
44#include "llvm/ADT/SmallPtrSet.h"
45#include "llvm/ADT/StringMap.h"
46#include "llvm/Support/Timer.h"
47
48namespace clang {
49
50namespace 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.
68class MatchFinder {
69public:
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 {
75 MatchResult(const BoundNodes &Nodes, clang::ASTContext *Context);
76
77 /// Contains the nodes bound on the current match.
78 ///
79 /// This allows user code to easily extract matched AST nodes.
80 const BoundNodes Nodes;
81
82 /// Utilities for interpreting the matched AST structures.
83 /// @{
84 clang::ASTContext * const Context;
85 clang::SourceManager * const SourceManager;
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 /// TraversalKind to use while matching and processing
115 /// the result nodes. This API is temporary to facilitate
116 /// third parties porting existing code to the default
117 /// behavior of clang-tidy.
118 virtual llvm::Optional<TraversalKind> getCheckTraversalKind() const;
119 };
120
121 /// Called when parsing is finished. Intended for testing only.
122 class ParsingDoneTestCallback {
123 public:
124 virtual ~ParsingDoneTestCallback();
125 virtual void run() = 0;
126 };
127
128 struct MatchFinderOptions {
129 struct Profiling {
130 Profiling(llvm::StringMap<llvm::TimeRecord> &Records)
131 : Records(Records) {}
132
133 /// Per bucket timing information.
134 llvm::StringMap<llvm::TimeRecord> &Records;
135 };
136
137 /// Enables per-check timers.
138 ///
139 /// It prints a report after match.
140 llvm::Optional<Profiling> CheckProfiling;
141 };
142
143 MatchFinder(MatchFinderOptions Options = MatchFinderOptions());
144 ~MatchFinder();
145
146 /// Adds a matcher to execute when running over the AST.
147 ///
148 /// Calls 'Action' with the BoundNodes on every match.
149 /// Adding more than one 'NodeMatch' allows finding different matches in a
150 /// single pass over the AST.
151 ///
152 /// Does not take ownership of 'Action'.
153 /// @{
154 void addMatcher(const DeclarationMatcher &NodeMatch,
155 MatchCallback *Action);
156 void addMatcher(const TypeMatcher &NodeMatch,
157 MatchCallback *Action);
158 void addMatcher(const StatementMatcher &NodeMatch,
159 MatchCallback *Action);
160 void addMatcher(const NestedNameSpecifierMatcher &NodeMatch,
161 MatchCallback *Action);
162 void addMatcher(const NestedNameSpecifierLocMatcher &NodeMatch,
163 MatchCallback *Action);
164 void addMatcher(const TypeLocMatcher &NodeMatch,
165 MatchCallback *Action);
166 void addMatcher(const CXXCtorInitializerMatcher &NodeMatch,
167 MatchCallback *Action);
168 void addMatcher(const TemplateArgumentLocMatcher &NodeMatch,
169 MatchCallback *Action);
170 /// @}
171
172 /// Adds a matcher to execute when running over the AST.
173 ///
174 /// This is similar to \c addMatcher(), but it uses the dynamic interface. It
175 /// is more flexible, but the lost type information enables a caller to pass
176 /// a matcher that cannot match anything.
177 ///
178 /// \returns \c true if the matcher is a valid top-level matcher, \c false
179 /// otherwise.
180 bool addDynamicMatcher(const internal::DynTypedMatcher &NodeMatch,
181 MatchCallback *Action);
182
183 /// Creates a clang ASTConsumer that finds all matches.
184 std::unique_ptr<clang::ASTConsumer> newASTConsumer();
185
186 /// Calls the registered callbacks on all matches on the given \p Node.
187 ///
188 /// Note that there can be multiple matches on a single node, for
189 /// example when using decl(forEachDescendant(stmt())).
190 ///
191 /// @{
192 template <typename T> void match(const T &Node, ASTContext &Context) {
193 match(clang::DynTypedNode::create(Node), Context);
194 }
195 void match(const clang::DynTypedNode &Node, ASTContext &Context);
196 /// @}
197
198 /// Finds all matches in the given AST.
199 void matchAST(ASTContext &Context);
200
201 /// Registers a callback to notify the end of parsing.
202 ///
203 /// The provided closure is called after parsing is done, before the AST is
204 /// traversed. Useful for benchmarking.
205 /// Each call to FindAll(...) will call the closure once.
206 void registerTestCallbackAfterParsing(ParsingDoneTestCallback *ParsingDone);
207
208 /// For each \c Matcher<> a \c MatchCallback that will be called
209 /// when it matches.
210 struct MatchersByType {
211 std::vector<std::pair<internal::DynTypedMatcher, MatchCallback *>>
212 DeclOrStmt;
213 std::vector<std::pair<TypeMatcher, MatchCallback *>> Type;
214 std::vector<std::pair<NestedNameSpecifierMatcher, MatchCallback *>>
215 NestedNameSpecifier;
216 std::vector<std::pair<NestedNameSpecifierLocMatcher, MatchCallback *>>
217 NestedNameSpecifierLoc;
218 std::vector<std::pair<TypeLocMatcher, MatchCallback *>> TypeLoc;
219 std::vector<std::pair<CXXCtorInitializerMatcher, MatchCallback *>> CtorInit;
220 std::vector<std::pair<TemplateArgumentLocMatcher, MatchCallback *>>
221 TemplateArgumentLoc;
222 /// All the callbacks in one container to simplify iteration.
223 llvm::SmallPtrSet<MatchCallback *, 16> AllCallbacks;
224 };
225
226private:
227 MatchersByType Matchers;
228
229 MatchFinderOptions Options;
230
231 /// Called when parsing is done.
232 ParsingDoneTestCallback *ParsingDone;
233};
234
235/// Returns the results of matching \p Matcher on \p Node.
236///
237/// Collects the \c BoundNodes of all callback invocations when matching
238/// \p Matcher on \p Node and returns the collected results.
239///
240/// Multiple results occur when using matchers like \c forEachDescendant,
241/// which generate a result for each sub-match.
242///
243/// If you want to find all matches on the sub-tree rooted at \c Node (rather
244/// than only the matches on \c Node itself), surround the \c Matcher with a
245/// \c findAll().
246///
247/// \see selectFirst
248/// @{
249template <typename MatcherT, typename NodeT>
250SmallVector<BoundNodes, 1>
251match(MatcherT Matcher, const NodeT &Node, ASTContext &Context);
252
253template <typename MatcherT>
254SmallVector<BoundNodes, 1> match(MatcherT Matcher, const DynTypedNode &Node,
255 ASTContext &Context);
256/// @}
257
258/// Returns the results of matching \p Matcher on the translation unit of
259/// \p Context and collects the \c BoundNodes of all callback invocations.
260template <typename MatcherT>
261SmallVector<BoundNodes, 1> match(MatcherT Matcher, ASTContext &Context);
262
263/// Returns the first result of type \c NodeT bound to \p BoundTo.
264///
265/// Returns \c NULL if there is no match, or if the matching node cannot be
266/// casted to \c NodeT.
267///
268/// This is useful in combanation with \c match():
269/// \code
270/// const Decl *D = selectFirst<Decl>("id", match(Matcher.bind("id"),
271/// Node, Context));
272/// \endcode
273template <typename NodeT>
274const NodeT *
275selectFirst(StringRef BoundTo, const SmallVectorImpl<BoundNodes> &Results) {
276 for (const BoundNodes &N : Results) {
277 if (const NodeT *Node = N.getNodeAs<NodeT>(BoundTo))
278 return Node;
279 }
280 return nullptr;
281}
282
283namespace internal {
284class CollectMatchesCallback : public MatchFinder::MatchCallback {
285public:
286 void run(const MatchFinder::MatchResult &Result) override {
287 Nodes.push_back(Result.Nodes);
288 }
289
290 llvm::Optional<TraversalKind> getCheckTraversalKind() const override {
291 return llvm::None;
292 }
293
294 SmallVector<BoundNodes, 1> Nodes;
295};
296}
297
298template <typename MatcherT>
299SmallVector<BoundNodes, 1> match(MatcherT Matcher, const DynTypedNode &Node,
300 ASTContext &Context) {
301 internal::CollectMatchesCallback Callback;
302 MatchFinder Finder;
303 Finder.addMatcher(Matcher, &Callback);
304 Finder.match(Node, Context);
305 return std::move(Callback.Nodes);
306}
307
308template <typename MatcherT, typename NodeT>
309SmallVector<BoundNodes, 1>
310match(MatcherT Matcher, const NodeT &Node, ASTContext &Context) {
311 return match(Matcher, DynTypedNode::create(Node), Context);
312}
313
314template <typename MatcherT>
315SmallVector<BoundNodes, 1>
316match(MatcherT Matcher, ASTContext &Context) {
317 internal::CollectMatchesCallback Callback;
318 MatchFinder Finder;
319 Finder.addMatcher(Matcher, &Callback);
320 Finder.matchAST(Context);
321 return std::move(Callback.Nodes);
322}
323
324inline SmallVector<BoundNodes, 1>
325matchDynamic(internal::DynTypedMatcher Matcher, const DynTypedNode &Node,
326 ASTContext &Context) {
327 internal::CollectMatchesCallback Callback;
328 MatchFinder Finder;
329 Finder.addDynamicMatcher(Matcher, &Callback);
330 Finder.match(Node, Context);
331 return std::move(Callback.Nodes);
332}
333
334template <typename NodeT>
335SmallVector<BoundNodes, 1> matchDynamic(internal::DynTypedMatcher Matcher,
336 const NodeT &Node,
337 ASTContext &Context) {
338 return matchDynamic(Matcher, DynTypedNode::create(Node), Context);
339}
340
341inline SmallVector<BoundNodes, 1>
342matchDynamic(internal::DynTypedMatcher Matcher, ASTContext &Context) {
343 internal::CollectMatchesCallback Callback;
344 MatchFinder Finder;
345 Finder.addDynamicMatcher(Matcher, &Callback);
346 Finder.matchAST(Context);
347 return std::move(Callback.Nodes);
348}
349
350} // end namespace ast_matchers
351} // end namespace clang
352
353#endif
354