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. 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. 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 { 125 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 /// @{ 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 first result of type \c NodeT bound to \p BoundTo. 245 /// 246 /// Returns \c NULL if there is no match, or if the matching node cannot be 247 /// casted to \c NodeT. 248 /// 249 /// This is useful in combanation with \c match(): 250 /// \code 251 /// const Decl *D = selectFirst<Decl>("id", match(Matcher.bind("id"), 252 /// Node, Context)); 253 /// \endcode 254 template <typename NodeT> 255 const NodeT * 256 selectFirst(StringRef BoundTo, const SmallVectorImpl<BoundNodes> &Results) { 257 for (const BoundNodes &N : Results) { 258 if (const NodeT *Node = N.getNodeAs<NodeT>(BoundTo)) 259 return Node; 260 } 261 return nullptr; 262 } 263 264 namespace internal { 265 class CollectMatchesCallback : public MatchFinder::MatchCallback { 266 public: 267 void run(const MatchFinder::MatchResult &Result) override { 268 Nodes.push_back(Result.Nodes); 269 } 270 SmallVector<BoundNodes, 1> Nodes; 271 }; 272 } 273 274 template <typename MatcherT> 275 SmallVector<BoundNodes, 1> 276 match(MatcherT Matcher, const ast_type_traits::DynTypedNode &Node, 277 ASTContext &Context) { 278 internal::CollectMatchesCallback Callback; 279 MatchFinder Finder; 280 Finder.addMatcher(Matcher, &Callback); 281 Finder.match(Node, Context); 282 return std::move(Callback.Nodes); 283 } 284 285 template <typename MatcherT, typename NodeT> 286 SmallVector<BoundNodes, 1> 287 match(MatcherT Matcher, const NodeT &Node, ASTContext &Context) { 288 return match(Matcher, ast_type_traits::DynTypedNode::create(Node), Context); 289 } 290 291 } // end namespace ast_matchers 292 } // end namespace clang 293 294 #endif 295