Make sure TraverseInitListExpr visits InitListExpr exactly twice

[sberg]

Summary

... once each for the syntactic and semantic form. Without this fix, behavior of the newly added tests would have been

InitListExprIsPreOrderVisitedTwice:
syntactic: 1
semantic: 2

InitListExprIsPostOrderVisitedTwice:
syntactic: 0
semantic: 1

InitListExprIsPreOrderNoQueueVisitedTwice:
syntactic: 1
semantic: 2

InitListExprIsPostOrderNoQueueVisitedTwice:
syntactic: 0
semantic: 2

[sberg]

committed as https://reviews.llvm.org/rL306374

include/clang/AST/RecursiveASTVisitor.h

 bool RecursiveASTVisitor<Derived>::PostVisitStmt(Stmt *S) {
   switch (S->getStmtClass()) {
   case Stmt::NoStmtClass:
     break;
 #define ABSTRACT_STMT(STMT)
 #define STMT(CLASS, PARENT)                                                    \
   case Stmt::CLASS##Class:                                                     \
     TRY_TO(WalkUpFrom##CLASS(static_cast<CLASS *>(S))); break;
+#define INITLISTEXPR(CLASS, PARENT)                                            \
+  case Stmt::CLASS##Class:                                                     \
+    {                                                                          \
+      auto ILE = static_cast<CLASS *>(S);                                      \
+      if (auto Syn = ILE->isSemanticForm() ? ILE->getSyntacticForm() : ILE)    \
+        TRY_TO(WalkUpFrom##CLASS(Syn));                                        \
+      if (auto Sem = ILE->isSemanticForm() ? ILE : ILE->getSemanticForm())     \
+        TRY_TO(WalkUpFrom##CLASS(Sem));                                        \
+      break;                                                                   \
+    }
 #include "clang/AST/StmtNodes.inc"
   }
 
   return true;
 }
 
 #undef DISPATCH_STMT
 

 }
 
 // This method is called once for each pair of syntactic and semantic
 // InitListExpr, and it traverses the subtrees defined by the two forms. This
 // may cause some of the children to be visited twice, if they appear both in
 // the syntactic and the semantic form.
 //
 // There is no guarantee about which form \p S takes when this method is called.
-DEF_TRAVERSE_STMT(InitListExpr, {
+template <typename Derived>
+bool RecursiveASTVisitor<Derived>::TraverseInitListExpr(
+    InitListExpr *S, DataRecursionQueue *Queue) {
   TRY_TO(TraverseSynOrSemInitListExpr(
       S->isSemanticForm() ? S->getSyntacticForm() : S, Queue));
   TRY_TO(TraverseSynOrSemInitListExpr(
       S->isSemanticForm() ? S : S->getSemanticForm(), Queue));
-  ShouldVisitChildren = false;
-})
+  return true;
+}
 
 // GenericSelectionExpr is a special case because the types and expressions
 // are interleaved.  We also need to watch out for null types (default
 // generic associations).
 DEF_TRAVERSE_STMT(GenericSelectionExpr, {
   TRY_TO(TraverseStmt(S->getControllingExpr()));
   for (unsigned i = 0; i != S->getNumAssocs(); ++i) {
     if (TypeSourceInfo *TS = S->getAssocTypeSourceInfo(i))

unittests/Tooling/RecursiveASTVisitorTest.cpp

 
 TEST(RecursiveASTVisitor, DefaultArgumentsAreVisited) {
   IntegerLiteralVisitor Visitor;
   Visitor.ExpectMatch("literal", 1, 15, 2);
   EXPECT_TRUE(Visitor.runOver("int f(int i = 1);\n"
                               "static int k = f();\n"));
 }
 
+// Check to ensure that InitListExpr is visited twice, once each for the
+// syntactic and semantic form.
+class InitListExprPreOrderVisitor
+    : public ExpectedLocationVisitor<InitListExprPreOrderVisitor> {
+public:
+  bool VisitInitListExpr(InitListExpr *ILE) {
+    Match(ILE->isSemanticForm() ? "semantic" : "syntactic", ILE->getLocStart());
+    return true;
+  }
+};
+
+class InitListExprPostOrderVisitor
+    : public ExpectedLocationVisitor<InitListExprPostOrderVisitor> {
+public:
+  bool shouldTraversePostOrder() const { return true; }
+
+  bool VisitInitListExpr(InitListExpr *ILE) {
+    Match(ILE->isSemanticForm() ? "semantic" : "syntactic", ILE->getLocStart());
+    return true;
+  }
+};
+
+class InitListExprPreOrderNoQueueVisitor
+    : public ExpectedLocationVisitor<InitListExprPreOrderNoQueueVisitor> {
+public:
+  bool TraverseInitListExpr(InitListExpr *ILE) {
+    return ExpectedLocationVisitor::TraverseInitListExpr(ILE);
+  }
+
+  bool VisitInitListExpr(InitListExpr *ILE) {
+    Match(ILE->isSemanticForm() ? "semantic" : "syntactic", ILE->getLocStart());
+    return true;
+  }
+};
+
+class InitListExprPostOrderNoQueueVisitor
+    : public ExpectedLocationVisitor<InitListExprPostOrderNoQueueVisitor> {
+public:
+  bool shouldTraversePostOrder() const { return true; }
+
+  bool TraverseInitListExpr(InitListExpr *ILE) {
+    return ExpectedLocationVisitor::TraverseInitListExpr(ILE);
+  }
+
+  bool VisitInitListExpr(InitListExpr *ILE) {
+    Match(ILE->isSemanticForm() ? "semantic" : "syntactic", ILE->getLocStart());
+    return true;
+  }
+};
+
+TEST(RecursiveASTVisitor, InitListExprIsPreOrderVisitedTwice) {
+  InitListExprPreOrderVisitor Visitor;
+  Visitor.ExpectMatch("syntactic", 2, 21);
+  Visitor.ExpectMatch("semantic", 2, 21);
+  EXPECT_TRUE(Visitor.runOver("struct S { int x; };\n"
+                              "static struct S s = {.x = 0};\n",
+                              InitListExprPreOrderVisitor::Lang_C));
+}
+
+TEST(RecursiveASTVisitor, InitListExprIsPostOrderVisitedTwice) {
+  InitListExprPostOrderVisitor Visitor;
+  Visitor.ExpectMatch("syntactic", 2, 21);
+  Visitor.ExpectMatch("semantic", 2, 21);
+  EXPECT_TRUE(Visitor.runOver("struct S { int x; };\n"
+                              "static struct S s = {.x = 0};\n",
+                              InitListExprPostOrderVisitor::Lang_C));
+}
+
+TEST(RecursiveASTVisitor, InitListExprIsPreOrderNoQueueVisitedTwice) {
+  InitListExprPreOrderNoQueueVisitor Visitor;
+  Visitor.ExpectMatch("syntactic", 2, 21);
+  Visitor.ExpectMatch("semantic", 2, 21);
+  EXPECT_TRUE(Visitor.runOver("struct S { int x; };\n"
+                              "static struct S s = {.x = 0};\n",
+                              InitListExprPreOrderNoQueueVisitor::Lang_C));
+}
+
+TEST(RecursiveASTVisitor, InitListExprIsPostOrderNoQueueVisitedTwice) {
+  InitListExprPostOrderNoQueueVisitor Visitor;
+  Visitor.ExpectMatch("syntactic", 2, 21);
+  Visitor.ExpectMatch("semantic", 2, 21);
+  EXPECT_TRUE(Visitor.runOver("struct S { int x; };\n"
+                              "static struct S s = {.x = 0};\n",
+                              InitListExprPostOrderNoQueueVisitor::Lang_C));
+}
+
 } // end anonymous namespace