Update `DynTypedNode` to support the conversion of `TypeLoc`s.

This provides better support for `TypeLoc`s to allow `TypeLoc`-related
matchers to feature stricter typing and to avoid relying on the dynamic
casting of `TypeLoc`s in matchers.

Reviewed By: ymandel, tdl-g, sbenza

Differential Revision: https://reviews.llvm.org/D110586

clang/include/clang/AST/ASTTypeTraits.h

@@ -63,6 +63,7 @@ public:
   static ASTNodeKind getFromNode(const Decl &D);
   static ASTNodeKind getFromNode(const Stmt &S);
   static ASTNodeKind getFromNode(const Type &T);
+  static ASTNodeKind getFromNode(const TypeLoc &T);
   static ASTNodeKind getFromNode(const OMPClause &C);
   static ASTNodeKind getFromNode(const Attr &A);
   /// \}
@@ -133,6 +134,8 @@ private:
     NKI_TemplateName,
     NKI_NestedNameSpecifierLoc,
     NKI_QualType,
+#define TYPELOC(CLASS, PARENT) NKI_##CLASS##TypeLoc,
+#include "clang/AST/TypeLocNodes.def"
     NKI_TypeLoc,
     NKI_LastKindWithoutPointerIdentity = NKI_TypeLoc,
     NKI_CXXBaseSpecifier,
@@ -198,6 +201,8 @@ KIND_TO_KIND_ID(TemplateName)
 KIND_TO_KIND_ID(NestedNameSpecifier)
 KIND_TO_KIND_ID(NestedNameSpecifierLoc)
 KIND_TO_KIND_ID(QualType)
+#define TYPELOC(CLASS, PARENT) KIND_TO_KIND_ID(CLASS##TypeLoc)
+#include "clang/AST/TypeLocNodes.def"
 KIND_TO_KIND_ID(TypeLoc)
 KIND_TO_KIND_ID(Decl)
 KIND_TO_KIND_ID(Stmt)
@@ -304,7 +309,7 @@ public:
       return getUnchecked<QualType>().getAsOpaquePtr() <
              Other.getUnchecked<QualType>().getAsOpaquePtr();
 
-    if (ASTNodeKind::getFromNodeKind<TypeLoc>().isSame(NodeKind)) {
+    if (ASTNodeKind::getFromNodeKind<TypeLoc>().isBaseOf(NodeKind)) {
       auto TLA = getUnchecked<TypeLoc>();
       auto TLB = Other.getUnchecked<TypeLoc>();
       return std::make_pair(TLA.getType().getAsOpaquePtr(),
@@ -336,7 +341,7 @@ public:
     if (ASTNodeKind::getFromNodeKind<QualType>().isSame(NodeKind))
       return getUnchecked<QualType>() == Other.getUnchecked<QualType>();
 
-    if (ASTNodeKind::getFromNodeKind<TypeLoc>().isSame(NodeKind))
+    if (ASTNodeKind::getFromNodeKind<TypeLoc>().isBaseOf(NodeKind))
       return getUnchecked<TypeLoc>() == Other.getUnchecked<TypeLoc>();
 
     if (ASTNodeKind::getFromNodeKind<NestedNameSpecifierLoc>().isSame(NodeKind))
@@ -365,7 +370,7 @@ public:
     }
     static unsigned getHashValue(const DynTypedNode &Val) {
       // FIXME: Add hashing support for the remaining types.
-      if (ASTNodeKind::getFromNodeKind<TypeLoc>().isSame(Val.NodeKind)) {
+      if (ASTNodeKind::getFromNodeKind<TypeLoc>().isBaseOf(Val.NodeKind)) {
         auto TL = Val.getUnchecked<TypeLoc>();
         return llvm::hash_combine(TL.getType().getAsOpaquePtr(),
                                   TL.getOpaqueData());
@@ -455,6 +460,29 @@ private:
     }
   };
 
+  /// Converter that stores nodes by value. It must be possible to dynamically
+  /// cast the stored node within a type hierarchy without breaking (especially
+  /// through slicing).
+  template <typename T, typename BaseT,
+            typename = std::enable_if_t<(sizeof(T) == sizeof(BaseT))>>
+  struct DynCastValueConverter {
+    static const T *get(ASTNodeKind NodeKind, const void *Storage) {
+      if (ASTNodeKind::getFromNodeKind<T>().isBaseOf(NodeKind))
+        return &getUnchecked(NodeKind, Storage);
+      return nullptr;
+    }
+    static const T &getUnchecked(ASTNodeKind NodeKind, const void *Storage) {
+      assert(ASTNodeKind::getFromNodeKind<T>().isBaseOf(NodeKind));
+      return *static_cast<const T *>(reinterpret_cast<const BaseT *>(Storage));
+    }
+    static DynTypedNode create(const T &Node) {
+      DynTypedNode Result;
+      Result.NodeKind = ASTNodeKind::getFromNode(Node);
+      new (&Result.Storage) T(Node);
+      return Result;
+    }
+  };
+
   ASTNodeKind NodeKind;
 
   /// Stores the data of the node.
@@ -525,9 +553,10 @@ template <>
 struct DynTypedNode::BaseConverter<QualType,
                                    void> : public ValueConverter<QualType> {};
 
-template <>
+template <typename T>
 struct DynTypedNode::BaseConverter<
-    TypeLoc, void> : public ValueConverter<TypeLoc> {};
+    T, std::enable_if_t<std::is_base_of<TypeLoc, T>::value>>
+    : public DynCastValueConverter<T, TypeLoc> {};
 
 template <>
 struct DynTypedNode::BaseConverter<CXXBaseSpecifier, void>

clang/lib/AST/ASTTypeTraits.cpp

@@ -18,6 +18,7 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/NestedNameSpecifier.h"
 #include "clang/AST/OpenMPClause.h"
+#include "clang/AST/TypeLoc.h"
 
 using namespace clang;
 
@@ -28,6 +29,8 @@ const ASTNodeKind::KindInfo ASTNodeKind::AllKindInfo[] = {
     {NKI_None, "TemplateName"},
     {NKI_None, "NestedNameSpecifierLoc"},
     {NKI_None, "QualType"},
+#define TYPELOC(CLASS, PARENT) {NKI_##PARENT, #CLASS "TypeLoc"},
+#include "clang/AST/TypeLocNodes.def"
     {NKI_None, "TypeLoc"},
     {NKI_None, "CXXBaseSpecifier"},
     {NKI_None, "CXXCtorInitializer"},
@@ -127,6 +130,17 @@ ASTNodeKind ASTNodeKind::getFromNode(const Type &T) {
   llvm_unreachable("invalid type kind");
  }
 
+ ASTNodeKind ASTNodeKind::getFromNode(const TypeLoc &T) {
+   switch (T.getTypeLocClass()) {
+#define ABSTRACT_TYPELOC(CLASS, PARENT)
+#define TYPELOC(CLASS, PARENT)                                                 \
+  case TypeLoc::CLASS:                                                         \
+    return ASTNodeKind(NKI_##CLASS##TypeLoc);
+#include "clang/AST/TypeLocNodes.def"
+   }
+   llvm_unreachable("invalid typeloc kind");
+ }
+
 ASTNodeKind ASTNodeKind::getFromNode(const OMPClause &C) {
   switch (C.getClauseKind()) {
 #define GEN_CLANG_CLAUSE_CLASS

clang/unittests/AST/ASTTypeTraitsTest.cpp

@@ -199,5 +199,41 @@ TEST(DynTypedNode, QualType) {
   EXPECT_FALSE(Node < Node);
 }
 
+TEST(DynTypedNode, TypeLoc) {
+  std::string code = R"cc(void example() { int abc; })cc";
+  auto AST = clang::tooling::buildASTFromCode(code);
+  auto matches =
+      match(traverse(TK_AsIs,
+                     varDecl(hasName("abc"), hasTypeLoc(typeLoc().bind("tl")))),
+            AST->getASTContext());
+  EXPECT_EQ(matches.size(), 1u);
+
+  const auto &tl = *matches[0].getNodeAs<TypeLoc>("tl");
+  DynTypedNode Node = DynTypedNode::create(tl);
+  EXPECT_TRUE(Node == Node);
+  EXPECT_FALSE(Node < Node);
+}
+
+TEST(DynTypedNode, PointerTypeLoc) {
+  std::string code = R"cc(void example() { int *abc; })cc";
+  auto AST = clang::tooling::buildASTFromCode(code);
+  auto matches =
+      match(traverse(TK_AsIs, varDecl(hasName("abc"),
+                                      hasTypeLoc(typeLoc().bind("ptl")))),
+            AST->getASTContext());
+  EXPECT_EQ(matches.size(), 1u);
+
+  const auto &tl = *matches[0].getNodeAs<TypeLoc>("ptl");
+  DynTypedNode TypeLocNode = DynTypedNode::create(tl);
+  EXPECT_TRUE(TypeLocNode == TypeLocNode);
+  EXPECT_FALSE(TypeLocNode < TypeLocNode);
+
+  const auto &ptl = *matches[0].getNodeAs<PointerTypeLoc>("ptl");
+  EXPECT_EQ(&tl, &ptl);
+  DynTypedNode PointerTypeLocNode = DynTypedNode::create(ptl);
+  EXPECT_TRUE(PointerTypeLocNode == PointerTypeLocNode);
+  EXPECT_FALSE(PointerTypeLocNode < PointerTypeLocNode);
+}
+
 } // namespace
 }  // namespace clang