Add API to retrieve a clade kind from ASTNodeKind

[aaron.ballman]

LGTM aside from the use of auto.

clang/lib/AST/ASTTypeTraits.cpp

67

69

clang/include/clang/AST/ASTTypeTraits.h

public:
   static ASTNodeKind getMostDerivedType(ASTNodeKind Kind1, ASTNodeKind Kind2);
 
   /// Return the most derived common ancestor between Kind1 and Kind2.
   ///
   /// Return ASTNodeKind() if they are not related.
   static ASTNodeKind getMostDerivedCommonAncestor(ASTNodeKind Kind1,
                                                   ASTNodeKind Kind2);
 
+  ASTNodeKind getCladeKind() const;
+
   /// Hooks for using ASTNodeKind as a key in a DenseMap.
   struct DenseMapInfo {
     // ASTNodeKind() is a good empty key because it is represented as a 0.
     static inline ASTNodeKind getEmptyKey() { return ASTNodeKind(); }
     // NKI_NumberOfKinds is not a valid value, so it is good for a
     // tombstone key.
     static inline ASTNodeKind getTombstoneKey() {
       return ASTNodeKind(NKI_NumberOfKinds);

clang/lib/AST/ASTTypeTraits.cpp

while (Derived != Base && Derived != NKI_None) {
     Derived = AllKindInfo[Derived].ParentId;
     ++Dist;
   }
   if (Distance)
     *Distance = Dist;
   return Derived == Base;
 }
 
+ASTNodeKind ASTNodeKind::getCladeKind() const {
+  NodeKindId LastId = KindId;
+  while (LastId) {
+    NodeKindId ParentId = AllKindInfo[LastId].ParentId;
+    if (ParentId == NKI_None)
+      return LastId;
+    LastId = ParentId;
+  }
+  return NKI_None;
+}
+
 StringRef ASTNodeKind::asStringRef() const { return AllKindInfo[KindId].Name; }
 
 ASTNodeKind ASTNodeKind::getMostDerivedType(ASTNodeKind Kind1,
                                             ASTNodeKind Kind2) {
   if (Kind1.isBaseOf(Kind2)) return Kind2;
   if (Kind2.isBaseOf(Kind1)) return Kind1;
   return ASTNodeKind();
 }

clang/unittests/AST/ASTTypeTraitsTest.cpp

 TEST(ASTNodeKind, Bases) {
   EXPECT_TRUE(DNT<Decl>().isBaseOf(DNT<VarDecl>()));
   EXPECT_FALSE(DNT<Decl>().isSame(DNT<VarDecl>()));
   EXPECT_FALSE(DNT<VarDecl>().isBaseOf(DNT<Decl>()));
 
   EXPECT_TRUE(DNT<Decl>().isSame(DNT<Decl>()));
 }
 
+TEST(DynTypedNode, Clades) {
+  EXPECT_TRUE(DNT<Stmt>().getCladeKind().isSame(DNT<Stmt>()));
+  EXPECT_TRUE(DNT<Decl>().getCladeKind().isSame(DNT<Decl>()));
+
+  EXPECT_TRUE(DNT<CXXMethodDecl>().getCladeKind().isSame(DNT<Decl>()));
+  EXPECT_TRUE(DNT<CXXMemberCallExpr>().getCladeKind().isSame(DNT<Stmt>()));
+
+  EXPECT_FALSE(DNT<CXXMemberCallExpr>().getCladeKind().isSame(DNT<Decl>()));
+
+  EXPECT_TRUE(ASTNodeKind().getCladeKind().isNone());
+}
+
 TEST(ASTNodeKind, BaseDistances) {
   unsigned Distance = 1;
   EXPECT_TRUE(DNT<Expr>().isBaseOf(DNT<Expr>(), &Distance));
   EXPECT_EQ(0u, Distance);
 
   EXPECT_TRUE(DNT<Stmt>().isBaseOf(DNT<IfStmt>(), &Distance));
   EXPECT_EQ(1u, Distance);