c++: support gcc's application of weak attribute on

class declaration which forces any such class and any 
class that inherits from such a class to have their 
typeinfo symbols be marked as weak.
// rdar://10246395
A    test/CodeGenCXX/weak-extern-typeinfo.cpp
M    lib/Sema/SemaDeclCXX.cpp
M    lib/Sema/SemaDeclAttr.cpp
M    lib/CodeGen/CGRTTI.cpp


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142693 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index b83b716fdf..d801664ad6 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -1914,6 +1914,10 @@ static void handleWeakAttr(Sema &S, Decl *D, const AttributeList &Attr) {
   }
 
   if (!isa<VarDecl>(D) && !isa<FunctionDecl>(D)) {
+    if (isa<CXXRecordDecl>(D)) {
+      D->addAttr(::new (S.Context) WeakAttr(Attr.getRange(), S.Context));
+      return;
+    }
     S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
       << Attr.getName() << ExpectedVariableOrFunction;
     return;