Add TemplateSpecializationType polymorphism for hasTemplateArgument and

hasAnyTemplateArgument, and (out of necessity) an isExpr matcher.

Also updates the TemplateArgument doxygen to reflect reality for
non-canonical template arguments.

Differential Revision: http://llvm-reviews.chandlerc.com/D2810

llvm-svn: 201804

clang/include/clang/AST/TemplateBase.h

@@ -34,8 +34,7 @@ struct PrintingPolicy;
 class TypeSourceInfo;
 class ValueDecl;
 
-/// \brief Represents a template argument within a class template
-/// specialization.
+/// \brief Represents a template argument.
 class TemplateArgument {
 public:
   /// \brief The kind of template argument we're storing.
@@ -60,8 +59,11 @@ public:
     /// The template argument is a pack expansion of a template name that was
     /// provided for a template template parameter.
     TemplateExpansion,
-    /// The template argument is a value- or type-dependent expression or a
-    /// non-dependent __uuidof expression stored in an Expr*.
+    /// The template argument is an expression, and we've not resolved it to one
+    /// of the other forms yet, either because it's dependent or because we're
+    /// representing a non-canonical template argument (for instance, in a
+    /// TemplateSpecializationType). Also used to represent a non-dependent
+    /// __uuidof expression (a Microsoft extension).
     Expression,
     /// The template argument is actually a parameter pack. Arguments are stored
     /// in the Args struct.

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -311,6 +311,18 @@ AST_MATCHER(Decl, isPrivate) {
   return Node.getAccess() == AS_private;
 }
 
+// FIXME: unify ClassTemplateSpecializationDecl and TemplateSpecializationType's
+// APIs for accessing the template argument list.
+inline llvm::ArrayRef<TemplateArgument>
+getTemplateSpecializationArgs(const ClassTemplateSpecializationDecl &D) {
+  return D.getTemplateArgs().asArray();
+}
+
+inline llvm::ArrayRef<TemplateArgument>
+getTemplateSpecializationArgs(const TemplateSpecializationType &T) {
+  return llvm::ArrayRef<TemplateArgument>(T.getArgs(), T.getNumArgs());
+}
+
 /// \brief Matches classTemplateSpecializations that have at least one
 /// TemplateArgument matching the given InnerMatcher.
 ///
@@ -323,9 +335,12 @@ AST_MATCHER(Decl, isPrivate) {
 /// classTemplateSpecializationDecl(hasAnyTemplateArgument(
 ///     refersToType(asString("int"))))
 ///   matches the specialization \c A<int>
-AST_MATCHER_P(ClassTemplateSpecializationDecl, hasAnyTemplateArgument,
+AST_POLYMORPHIC_MATCHER_P(
+    hasAnyTemplateArgument,
+    AST_POLYMORPHIC_SUPPORTED_TYPES_2(ClassTemplateSpecializationDecl,
+                                      TemplateSpecializationType),
     internal::Matcher<TemplateArgument>, InnerMatcher) {
-  llvm::ArrayRef<TemplateArgument> List = Node.getTemplateArgs().asArray();
+  llvm::ArrayRef<TemplateArgument> List = getTemplateSpecializationArgs(Node);
   return matchesFirstInRange(InnerMatcher, List.begin(), List.end(), Finder,
                              Builder);
 }
@@ -419,12 +434,15 @@ AST_MATCHER_P(Expr, ignoringParenImpCasts,
 /// classTemplateSpecializationDecl(hasTemplateArgument(
 ///     1, refersToType(asString("int"))))
 ///   matches the specialization \c A<bool, int>
-AST_MATCHER_P2(ClassTemplateSpecializationDecl, hasTemplateArgument,
+AST_POLYMORPHIC_MATCHER_P2(
+    hasTemplateArgument,
+    AST_POLYMORPHIC_SUPPORTED_TYPES_2(ClassTemplateSpecializationDecl,
+                                      TemplateSpecializationType),
     unsigned, N, internal::Matcher<TemplateArgument>, InnerMatcher) {
-  const TemplateArgumentList &List = Node.getTemplateArgs();
+  llvm::ArrayRef<TemplateArgument> List = getTemplateSpecializationArgs(Node);
   if (List.size() <= N)
     return false;
-  return InnerMatcher.matches(List.get(N), Finder, Builder);
+  return InnerMatcher.matches(List[N], Finder, Builder);
 }
 
 /// \brief Matches a TemplateArgument that refers to a certain type.
@@ -445,7 +463,8 @@ AST_MATCHER_P(TemplateArgument, refersToType,
   return InnerMatcher.matches(Node.getAsType(), Finder, Builder);
 }
 
-/// \brief Matches a TemplateArgument that refers to a certain declaration.
+/// \brief Matches a canonical TemplateArgument that refers to a certain
+/// declaration.
 ///
 /// Given
 /// \code
@@ -464,6 +483,24 @@ AST_MATCHER_P(TemplateArgument, refersToDeclaration,
   return false;
 }
 
+/// \brief Matches a sugar TemplateArgument that refers to a certain expression.
+///
+/// Given
+/// \code
+///   template<typename T> struct A {};
+///   struct B { B* next; };
+///   A<&B::next> a;
+/// \endcode
+/// templateSpecializationType(hasAnyTemplateArgument(
+///   isExpr(hasDescendant(declRefExpr(to(fieldDecl(hasName("next"))))))))
+///   matches the specialization \c A<&B::next> with \c fieldDecl(...) matching
+///     \c B::next
+AST_MATCHER_P(TemplateArgument, isExpr, internal::Matcher<Expr>, InnerMatcher) {
+  if (Node.getKind() == TemplateArgument::Expression)
+    return InnerMatcher.matches(*Node.getAsExpr(), Finder, Builder);
+  return false;
+}
+
 /// \brief Matches C++ constructor declarations.
 ///
 /// Example matches Foo::Foo() and Foo::Foo(int)

clang/lib/ASTMatchers/Dynamic/Registry.cpp

@@ -228,6 +228,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(isConstQualified);
   REGISTER_MATCHER(isDefinition);
   REGISTER_MATCHER(isExplicitTemplateSpecialization);
+  REGISTER_MATCHER(isExpr);
   REGISTER_MATCHER(isExternC);
   REGISTER_MATCHER(isImplicit);
   REGISTER_MATCHER(isInteger);

clang/unittests/ASTMatchers/ASTMatchersTest.cpp

@@ -1530,6 +1530,19 @@ TEST(Matcher, MatchesDeclarationReferenceTemplateArgument) {
       "A<int> a;",
       classTemplateSpecializationDecl(hasAnyTemplateArgument(
           refersToDeclaration(decl())))));
+
+  EXPECT_TRUE(matches(
+      "struct B { int next; };"
+      "template<int(B::*next_ptr)> struct A {};"
+      "A<&B::next> a;",
+      templateSpecializationType(hasAnyTemplateArgument(isExpr(
+          hasDescendant(declRefExpr(to(fieldDecl(hasName("next"))))))))));
+
+  EXPECT_TRUE(notMatches(
+      "template <typename T> struct A {};"
+      "A<int> a;",
+      templateSpecializationType(hasAnyTemplateArgument(
+          refersToDeclaration(decl())))));
 }
 
 TEST(Matcher, MatchesSpecificArgument) {
@@ -1543,6 +1556,17 @@ TEST(Matcher, MatchesSpecificArgument) {
       "A<int, bool> a;",
       classTemplateSpecializationDecl(hasTemplateArgument(
           1, refersToType(asString("int"))))));
+
+  EXPECT_TRUE(matches(
+      "template<typename T, typename U> class A {};"
+      "A<bool, int> a;",
+      templateSpecializationType(hasTemplateArgument(
+          1, refersToType(asString("int"))))));
+  EXPECT_TRUE(notMatches(
+      "template<typename T, typename U> class A {};"
+      "A<int, bool> a;",
+      templateSpecializationType(hasTemplateArgument(
+          1, refersToType(asString("int"))))));
 }
 
 TEST(Matcher, MatchesAccessSpecDecls) {