Process attributes in the order they appear in the source code. This make clang

match gcc behavior for two conflicting visibilities in the same decl. It also
makes handling of dllimport/dllexport more natural.

As a bonus we now warn on the dllimport in

void __attribute__((dllimport)) foo13();
void __attribute__((dllexport)) foo13();

as does gcc.

llvm-svn: 156343

1 files changed, 5 insertions, 10 deletions

diff --git a/clang/lib/Sema/TargetAttributesSema.cpp b/clang/lib/Sema/TargetAttributesSema.cpp
index 8b19be74dd4..c0746388e59 100644
--- a/clang/lib/Sema/TargetAttributesSema.cpp
+++ b/clang/lib/Sema/TargetAttributesSema.cpp
@@ -182,16 +182,6 @@ static void HandleDLLImportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
     return;
   }
 
-  // The attribute is also overridden by a subsequent declaration as dllexport.
-  // Warning is emitted.
-  for (AttributeList *nextAttr = Attr.getNext(); nextAttr;
-       nextAttr = nextAttr->getNext()) {
-    if (nextAttr->getKind() == AttributeList::AT_dllexport) {
-      S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << "dllimport";
-      return;
-    }
-  }
-
   if (D->getAttr<DLLExportAttr>()) {
     S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << "dllimport";
     return;
@@ -228,6 +218,11 @@ static void HandleDLLExportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
     return;
   }
 
+  if (DLLImportAttr *Import = D->getAttr<DLLImportAttr>()) {
+    S.Diag(Import->getLocation(), diag::warn_attribute_ignored) << "dllimport";
+    D->dropAttr<DLLImportAttr>();
+  }
+
   D->addAttr(::new (S.Context) DLLExportAttr(Attr.getLoc(), S.Context));
 }