3 files changed, 38 insertions, 0 deletions
diff --git a/include/clang/ASTMatchers/ASTMatchFinder.h b/include/clang/ASTMatchers/ASTMatchFinder.h
index ba8e0a7ecc..30b4050e1c 100644
--- a/include/clang/ASTMatchers/ASTMatchFinder.h
+++ b/include/clang/ASTMatchers/ASTMatchFinder.h
@@ -85,7 +85,14 @@ public:
   class MatchCallback {
   public:
     virtual ~MatchCallback();
+
+    /// \brief Called on every match by the \c MatchFinder.
     virtual void run(const MatchResult &Result) = 0;
+
+    /// \brief Called at the start of each translation unit.
+    ///
+    /// Optionally override to do per translation unit tasks.
+    virtual void onStartOfTranslationUnit() {}
   };
 
   /// \brief Called when parsing is finished. Intended for testing only.
diff --git a/lib/ASTMatchers/ASTMatchFinder.cpp b/lib/ASTMatchers/ASTMatchFinder.cpp
index b081f5426e..8ecb26e8c1 100644
--- a/lib/ASTMatchers/ASTMatchFinder.cpp
+++ b/lib/ASTMatchers/ASTMatchFinder.cpp
@@ -315,6 +315,15 @@ public:
        ActiveASTContext(NULL) {
   }
 
+  void onStartOfTranslationUnit() {
+    for (std::vector<std::pair<const internal::DynTypedMatcher*,
+                               MatchCallback*> >::const_iterator
+             I = MatcherCallbackPairs->begin(), E = MatcherCallbackPairs->end();
+         I != E; ++I) {
+      I->second->onStartOfTranslationUnit();
+    }
+  }
+
   void set_active_ast_context(ASTContext *NewActiveASTContext) {
     ActiveASTContext = NewActiveASTContext;
   }
@@ -649,6 +658,7 @@ private:
       ParsingDone->run();
     }
     Visitor.set_active_ast_context(&Context);
+    Visitor.onStartOfTranslationUnit();
     Visitor.TraverseDecl(Context.getTranslationUnitDecl());
     Visitor.set_active_ast_context(NULL);
   }
diff --git a/unittests/ASTMatchers/ASTMatchersTest.cpp b/unittests/ASTMatchers/ASTMatchersTest.cpp
index 8861881efa..ad5469348d 100644
--- a/unittests/ASTMatchers/ASTMatchersTest.cpp
+++ b/unittests/ASTMatchers/ASTMatchersTest.cpp
@@ -3366,5 +3366,26 @@ TEST(MatchFinder, CanMatchStatementsRecursively) {
     new VerifyRecursiveMatch<clang::Stmt>("if", declStmt())));
 }
 
+class VerifyStartOfTranslationUnit : public MatchFinder::MatchCallback {
+public:
+  VerifyStartOfTranslationUnit() : Called(false) {}
+  virtual void run(const MatchFinder::MatchResult &Result) {
+    EXPECT_TRUE(Called);
+  }
+  virtual void onStartOfTranslationUnit() {
+    Called = true;
+  }
+  bool Called;
+};
+
+TEST(MatchFinder, InterceptsStartOfTranslationUnit) {
+  MatchFinder Finder;
+  VerifyStartOfTranslationUnit VerifyCallback;
+  Finder.addMatcher(decl(), &VerifyCallback);
+  OwningPtr<FrontendActionFactory> Factory(newFrontendActionFactory(&Finder));
+  ASSERT_TRUE(tooling::runToolOnCode(Factory->create(), "int x;"));
+  EXPECT_TRUE(VerifyCallback.Called);
+}
+
 } // end namespace ast_matchers
 } // end namespace clang