[AST] Respect shouldTraversePostOrder when traversing type locs

[hlopko]

Summary

Copy of https://reviews.llvm.org/D72072, submitting with ilya-biryukov's permission.

clang/include/clang/AST/RecursiveASTVisitor.h

 // This macro makes available a variable TL, the passed-in TypeLoc.
 // If requested, it calls WalkUpFrom* for the Type in the given TypeLoc,
 // in addition to WalkUpFrom* for the TypeLoc itself, such that existing
 // clients that override the WalkUpFrom*Type() and/or Visit*Type() methods
 // continue to work.
 #define DEF_TRAVERSE_TYPELOC(TYPE, CODE)                                       \
   template <typename Derived>                                                  \
   bool RecursiveASTVisitor<Derived>::Traverse##TYPE##Loc(TYPE##Loc TL) {       \
-    if (getDerived().shouldWalkTypesOfTypeLocs())                              \
-      TRY_TO(WalkUpFrom##TYPE(const_cast<TYPE *>(TL.getTypePtr())));           \
-    TRY_TO(WalkUpFrom##TYPE##Loc(TL));                                         \
+    if (!getDerived().shouldTraversePostOrder()) {                             \
+      TRY_TO(WalkUpFrom##TYPE##Loc(TL));                                       \
+      if (getDerived().shouldWalkTypesOfTypeLocs())                            \
+        TRY_TO(WalkUpFrom##TYPE(const_cast<TYPE *>(TL.getTypePtr())));         \
+    }                                                                          \
     { CODE; }                                                                  \
+    if (getDerived().shouldTraversePostOrder()) {                              \
+      TRY_TO(WalkUpFrom##TYPE##Loc(TL));                                       \
+      if (getDerived().shouldWalkTypesOfTypeLocs())                            \
+        TRY_TO(WalkUpFrom##TYPE(const_cast<TYPE *>(TL.getTypePtr())));         \
+    }                                                                          \
     return true;                                                               \
   }
 
 template <typename Derived>
 bool
 RecursiveASTVisitor<Derived>::TraverseQualifiedTypeLoc(QualifiedTypeLoc TL) {
   // Move this over to the 'main' typeloc tree.  Note that this is a
   // move -- we pretend that we were really looking at the unqualified

 bool RecursiveASTVisitor<Derived>::TraverseArrayTypeLocHelper(ArrayTypeLoc TL) {
   // This isn't available for ArrayType, but is for the ArrayTypeLoc.
   TRY_TO(TraverseStmt(TL.getSizeExpr()));
   return true;
 }
 
 DEF_TRAVERSE_TYPELOC(ConstantArrayType, {
   TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
-  return TraverseArrayTypeLocHelper(TL);
+  TRY_TO(TraverseArrayTypeLocHelper(TL));
 })
 
 DEF_TRAVERSE_TYPELOC(IncompleteArrayType, {
   TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
-  return TraverseArrayTypeLocHelper(TL);
+  TRY_TO(TraverseArrayTypeLocHelper(TL));
 })
 
 DEF_TRAVERSE_TYPELOC(VariableArrayType, {
   TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
-  return TraverseArrayTypeLocHelper(TL);
+  TRY_TO(TraverseArrayTypeLocHelper(TL));
 })
 
 DEF_TRAVERSE_TYPELOC(DependentSizedArrayType, {
   TRY_TO(TraverseTypeLoc(TL.getElementLoc()));
-  return TraverseArrayTypeLocHelper(TL);
+  TRY_TO(TraverseArrayTypeLocHelper(TL));
 })
 
 DEF_TRAVERSE_TYPELOC(DependentAddressSpaceType, {
   TRY_TO(TraverseStmt(TL.getTypePtr()->getAddrSpaceExpr()));
   TRY_TO(TraverseType(TL.getTypePtr()->getPointeeType()));
 })
 
 // FIXME: order? why not size expr first?