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_AST_MATCHERS_AST_MATCH_FINDER_H 42#define LLVM_CLANG_AST_MATCHERS_AST_MATCH_FINDER_H 43 44#include "clang/ASTMatchers/ASTMatchers.h" 45 46namespace clang { 47 48namespace ast_matchers { 49 50/// \brief A class to allow finding matches over the Clang AST. 51/// 52/// After creation, you can add multiple matchers to the MatchFinder via 53/// calls to addMatcher(...). 54/// 55/// Once all matchers are added, newASTConsumer() returns an ASTConsumer 56/// that will trigger the callbacks specified via addMatcher(...) when a match 57/// is found. 58/// 59/// The order of matches is guaranteed to be equivalent to doing a pre-order 60/// traversal on the AST, and applying the matchers in the order in which they 61/// were added to the MatchFinder. 62/// 63/// See ASTMatchers.h for more information about how to create matchers. 64/// 65/// Not intended to be subclassed. 66class MatchFinder { 67public: 68 /// \brief Contains all information for a given match. 69 /// 70 /// Every time a match is found, the MatchFinder will invoke the registered 71 /// MatchCallback with a MatchResult containing information about the match. 72 struct MatchResult { 73 MatchResult(const BoundNodes &Nodes, clang::ASTContext *Context); 74 75 /// \brief Contains the nodes bound on the current match. 76 /// 77 /// This allows user code to easily extract matched AST nodes. 78 const BoundNodes Nodes; 79 80 /// \brief Utilities for interpreting the matched AST structures. 81 /// @{ 82 clang::ASTContext * const Context; 83 clang::SourceManager * const SourceManager; 84 /// @} 85 }; 86 87 /// \brief Called when the Match registered for it was successfully found 88 /// in the AST. 89 class MatchCallback { 90 public: 91 virtual ~MatchCallback(); 92 93 /// \brief Called on every match by the \c MatchFinder. 94 virtual void run(const MatchResult &Result) = 0; 95 96 /// \brief Called at the start of each translation unit. 97 /// 98 /// Optionally override to do per translation unit tasks. 99 virtual void onStartOfTranslationUnit() {} 100 101 /// \brief Called at the end of each translation unit. 102 /// 103 /// Optionally override to do per translation unit tasks. 104 virtual void onEndOfTranslationUnit() {} 105 }; 106 107 /// \brief Called when parsing is finished. Intended for testing only. 108 class ParsingDoneTestCallback { 109 public: 110 virtual ~ParsingDoneTestCallback(); 111 virtual void run() = 0; 112 }; 113 114 MatchFinder(); 115 ~MatchFinder(); 116 117 /// \brief Adds a matcher to execute when running over the AST. 118 /// 119 /// Calls 'Action' with the BoundNodes on every match. 120 /// Adding more than one 'NodeMatch' allows finding different matches in a 121 /// single pass over the AST. 122 /// 123 /// Does not take ownership of 'Action'. 124 /// @{ 125 void addMatcher(const DeclarationMatcher &NodeMatch, 126 MatchCallback *Action); 127 void addMatcher(const TypeMatcher &NodeMatch, 128 MatchCallback *Action); 129 void addMatcher(const StatementMatcher &NodeMatch, 130 MatchCallback *Action); 131 void addMatcher(const NestedNameSpecifierMatcher &NodeMatch, 132 MatchCallback *Action); 133 void addMatcher(const NestedNameSpecifierLocMatcher &NodeMatch, 134 MatchCallback *Action); 135 void addMatcher(const TypeLocMatcher &NodeMatch, 136 MatchCallback *Action); 137 /// @} 138 139 /// \brief Creates a clang ASTConsumer that finds all matches. 140 clang::ASTConsumer *newASTConsumer(); 141 142 /// \brief Calls the registered callbacks on all matches on the given \p Node. 143 /// 144 /// Note that there can be multiple matches on a single node, for 145 /// example when using decl(forEachDescendant(stmt())). 146 /// 147 /// @{ 148 template <typename T> void match(const T &Node, ASTContext &Context) { 149 match(clang::ast_type_traits::DynTypedNode::create(Node), Context); 150 } 151 void match(const clang::ast_type_traits::DynTypedNode &Node, 152 ASTContext &Context); 153 /// @} 154 155 /// \brief Registers a callback to notify the end of parsing. 156 /// 157 /// The provided closure is called after parsing is done, before the AST is 158 /// traversed. Useful for benchmarking. 159 /// Each call to FindAll(...) will call the closure once. 160 void registerTestCallbackAfterParsing(ParsingDoneTestCallback *ParsingDone); 161 162private: 163 /// \brief For each \c DynTypedMatcher a \c MatchCallback that will be called 164 /// when it matches. 165 std::vector<std::pair<const internal::DynTypedMatcher*, MatchCallback*> > 166 MatcherCallbackPairs; 167 168 /// \brief Called when parsing is done. 169 ParsingDoneTestCallback *ParsingDone; 170}; 171 172/// \brief Returns the results of matching \p Matcher on \p Node. 173/// 174/// Collects the \c BoundNodes of all callback invocations when matching 175/// \p Matcher on \p Node and returns the collected results. 176/// 177/// Multiple results occur when using matchers like \c forEachDescendant, 178/// which generate a result for each sub-match. 179/// 180/// \see selectFirst 181/// @{ 182template <typename MatcherT, typename NodeT> 183SmallVector<BoundNodes, 1> 184match(MatcherT Matcher, const NodeT &Node, ASTContext &Context); 185 186template <typename MatcherT> 187SmallVector<BoundNodes, 1> 188match(MatcherT Matcher, const ast_type_traits::DynTypedNode &Node, 189 ASTContext &Context); 190/// @} 191 192/// \brief Returns the first result of type \c NodeT bound to \p BoundTo. 193/// 194/// Returns \c NULL if there is no match, or if the matching node cannot be 195/// casted to \c NodeT. 196/// 197/// This is useful in combanation with \c match(): 198/// \code 199/// Decl *D = selectFirst<Decl>("id", match(Matcher.bind("id"), 200/// Node, Context)); 201/// \endcode 202template <typename NodeT> 203NodeT * 204selectFirst(StringRef BoundTo, const SmallVectorImpl<BoundNodes> &Results) { 205 for (SmallVectorImpl<BoundNodes>::const_iterator I = Results.begin(), 206 E = Results.end(); 207 I != E; ++I) { 208 if (NodeT *Node = I->getNodeAs<NodeT>(BoundTo)) 209 return Node; 210 } 211 return NULL; 212} 213 214namespace internal { 215class CollectMatchesCallback : public MatchFinder::MatchCallback { 216public: 217 virtual void run(const MatchFinder::MatchResult &Result) { 218 Nodes.push_back(Result.Nodes); 219 } 220 SmallVector<BoundNodes, 1> Nodes; 221}; 222} 223 224template <typename MatcherT> 225SmallVector<BoundNodes, 1> 226match(MatcherT Matcher, const ast_type_traits::DynTypedNode &Node, 227 ASTContext &Context) { 228 internal::CollectMatchesCallback Callback; 229 MatchFinder Finder; 230 Finder.addMatcher(Matcher, &Callback); 231 Finder.match(Node, Context); 232 return Callback.Nodes; 233} 234 235template <typename MatcherT, typename NodeT> 236SmallVector<BoundNodes, 1> 237match(MatcherT Matcher, const NodeT &Node, ASTContext &Context) { 238 return match(Matcher, ast_type_traits::DynTypedNode::create(Node), Context); 239} 240 241} // end namespace ast_matchers 242} // end namespace clang 243 244#endif // LLVM_CLANG_AST_MATCHERS_AST_MATCH_FINDER_H 245