Generalize our two different kinds of declaration argument for

attributes to support any kind of declaration.

In preparation for adding a third kind.

Author: zygoloid

clang/include/clang/Basic/Attr.td

@@ -174,12 +174,10 @@ class IdentifierArgument<string name, bit opt = 0> : Argument<name, opt>;
 class IntArgument<string name, bit opt = 0> : Argument<name, opt>;
 class StringArgument<string name, bit opt = 0> : Argument<name, opt>;
 class ExprArgument<string name, bit opt = 0> : Argument<name, opt>;
-class FunctionArgument<string name, bit opt = 0, bit fake = 0> : Argument<name,
-                                                                          opt,
-                                                                          fake>;
-class NamedArgument<string name, bit opt = 0, bit fake = 0> : Argument<name,
-                                                                       opt,
-                                                                       fake>;
+class DeclArgument<DeclNode kind, string name, bit opt = 0, bit fake = 0>
+    : Argument<name, opt, fake> {
+  DeclNode Kind = kind;
+}
 
 // An argument of a OMPDeclareVariantAttr that represents the `match`
 // clause of the declare variant by keeping the information (incl. nesting) in
@@ -956,7 +954,7 @@ def OSConsumesThis : InheritableAttr {
 
 def Cleanup : InheritableAttr {
   let Spellings = [GCC<"cleanup">];
-  let Args = [FunctionArgument<"FunctionDecl">];
+  let Args = [DeclArgument<Function, "FunctionDecl">];
   let Subjects = SubjectList<[LocalVar]>;
   let Documentation = [Undocumented];
 }
@@ -2382,7 +2380,7 @@ def DiagnoseIf : InheritableAttr {
                            ["error", "warning"],
                            ["DT_Error", "DT_Warning"]>,
               BoolArgument<"ArgDependent", 0, /*fake*/ 1>,
-              NamedArgument<"Parent", 0, /*fake*/ 1>];
+              DeclArgument<Named, "Parent", 0, /*fake*/ 1>];
   let InheritEvenIfAlreadyPresent = 1;
   let LateParsed = 1;
   let AdditionalMembers = [{

clang/utils/TableGen/ClangAttrEmitter.cpp

@@ -339,7 +339,7 @@ namespace {
     }
 
     void writeDump(raw_ostream &OS) const override {
-      if (type == "FunctionDecl *" || type == "NamedDecl *") {
+      if (StringRef(type).endswith("Decl *")) {
         OS << "    OS << \" \";\n";
         OS << "    dumpBareDeclRef(SA->get" << getUpperName() << "());\n";
       } else if (type == "IdentifierInfo *") {
@@ -1290,10 +1290,9 @@ createArgument(const Record &Arg, StringRef Attr,
     Ptr = std::make_unique<EnumArgument>(Arg, Attr);
   else if (ArgName == "ExprArgument")
     Ptr = std::make_unique<ExprArgument>(Arg, Attr);
-  else if (ArgName == "FunctionArgument")
-    Ptr = std::make_unique<SimpleArgument>(Arg, Attr, "FunctionDecl *");
-  else if (ArgName == "NamedArgument")
-    Ptr = std::make_unique<SimpleArgument>(Arg, Attr, "NamedDecl *");
+  else if (ArgName == "DeclArgument")
+    Ptr = std::make_unique<SimpleArgument>(
+        Arg, Attr, (Arg.getValueAsDef("Kind")->getName() + "Decl *").str());
   else if (ArgName == "IdentifierArgument")
     Ptr = std::make_unique<SimpleArgument>(Arg, Attr, "IdentifierInfo *");
   else if (ArgName == "DefaultBoolArgument")