Don't suppress warning about dllimport on non-functions and variables

[hans]

Summary

This warning suppression in MS extensions mode was added by Ted in r96722.

It's true that MSVC doesn't warn about dllimport when applied to e.g. a typedef, but that applies to dllexport too. I would like us to be consistent between the two attributes, and I think the right thing to do is to warn. Ted: is there still a need to suppress this warning? (If yes, I'd like to make it consistent and suppress the warning for dllexport too).

[hans]

Ping?

[hans]

Closed by commit rL209546 (authored by @hans).

include/clang/Basic/Attr.td

 def DLLExport : InheritableAttr, TargetSpecificAttr<TargetWindows> {
   let Spellings = [Declspec<"dllexport">, GCC<"dllexport">];
   let Subjects = SubjectList<[Function, Var]>;
   let Documentation = [Undocumented];
 }
 
 def DLLImport : InheritableAttr, TargetSpecificAttr<TargetWindows> {
   let Spellings = [Declspec<"dllimport">, GCC<"dllimport">];
-  // Technically, the subjects for DllImport are Function and Var, but there is
-  // custom semantic handling required when MicrosoftExt is true.
+  let Subjects = SubjectList<[Function, Var]>;
   let Documentation = [Undocumented];
 }
 
 def SelectAny : InheritableAttr {
   let Spellings = [Declspec<"selectany">];
   let LangOpts = [MicrosoftExt];
   let Documentation = [Undocumented];
 }

lib/Sema/SemaDeclAttr.cpp

DLLImportAttr *Sema::mergeDLLImportAttr(Decl *D, SourceRange Range,
 
   if (D->hasAttr<DLLImportAttr>())
     return NULL;
 
   return ::new (Context) DLLImportAttr(Range, Context, AttrSpellingListIndex);
 }
 
 static void handleDLLImportAttr(Sema &S, Decl *D, const AttributeList &Attr) {
-  // Attribute can be applied only to functions or variables.
-  FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
-  if (!FD && !isa<VarDecl>(D)) {
-    // Apparently Visual C++ thinks it is okay to not emit a warning
-    // in this case, so only emit a warning when -fms-extensions is not
-    // specified.
-    if (!S.getLangOpts().MicrosoftExt)
-      S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
-        << Attr.getName() << ExpectedVariableOrFunction;
-    return;
-  }
-
   unsigned Index = Attr.getAttributeSpellingListIndex();
   DLLImportAttr *NewAttr = S.mergeDLLImportAttr(D, Attr.getRange(), Index);
   if (NewAttr)
     D->addAttr(NewAttr);
 }
 
 DLLExportAttr *Sema::mergeDLLExportAttr(Decl *D, SourceRange Range,
                                         unsigned AttrSpellingListIndex) {

test/Rewriter/dllimport-typedef.c

-// RUN: not %clang_cc1 -triple i686-pc-win32 -fms-extensions -fsyntax-only %s 2>&1 | FileCheck -check-prefix=CHECK-NEG %s
-// RUN: not %clang_cc1 -triple i686-pc-win32 -fsyntax-only %s 2>&1 | FileCheck -check-prefix=CHECK-POS %s
-
-// Do not report an error with including dllimport in the typedef when -fms-extensions is specified.
-// Addresses <rdar://problem/7653870>.
-typedef __declspec(dllimport) int CB(void);
-
-// This function is added just to trigger a diagnostic.  This way we can test how many
-// diagnostics we expect.
-void bar() { return 1; }
-
-// CHECK-NEG: error: void function 'bar' should not return a value
-// CHECK-NEG: {{^}}1 error generated
-// CHECK-POS: warning: 'dllimport' attribute only applies to variables and functions
-// CHECK-POS: error: void function 'bar' should not return a value
-// CHECK-POS: 1 warning and 1 error generated
-