Giving a Subjects list to DllExport, which allows the removal of some custom...

Giving a Subjects list to DllExport, which allows the removal of some custom semantic handling. The same cannot be done for DllImport, and so comments were left explaining why.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196429 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/Attr.td

@@ -1189,10 +1189,13 @@ def MsStruct : InheritableAttr {
 
 def DLLExport : InheritableAttr, TargetSpecificAttr {
   let Spellings = [Declspec<"dllexport">];
+  let Subjects = SubjectList<[Function, Var]>;
 }
 
 def DLLImport : InheritableAttr, TargetSpecificAttr {
   let Spellings = [Declspec<"dllimport">];
+  // Technically, the subjects for DllImport are Function and Var, but there is
+  // custom semantic handling required when MicrosoftExt is true.
 }
 
 def ForceInline : InheritableAttr {

lib/Sema/TargetAttributesSema.cpp

@@ -201,17 +201,9 @@ DLLExportAttr *Sema::mergeDLLExportAttr(Decl *D, SourceRange Range,
 }
 
 static void HandleDLLExportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
-  // Attribute can be applied only to functions or variables.
-  FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
-  if (!FD && !isa<VarDecl>(D)) {
-    S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
-      << Attr.getName() << 2 /*variable and function*/;
-    return;
-  }
-
   // Currently, the dllexport attribute is ignored for inlined functions, unless
   // the -fkeep-inline-functions flag has been used. Warning is emitted;
-  if (FD && FD->isInlineSpecified()) {
+  if (isa<FunctionDecl>(D) && cast<FunctionDecl>(D)->isInlineSpecified()) {
     // FIXME: ... unless the -fkeep-inline-functions flag has been used.
     S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
     return;