Disable the "'extern' variable has an initializer" warning in C++,

since it makes sense there to have const extern variables. Fixes
PR6495.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101818 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaDecl.cpp

@@ -3818,7 +3818,8 @@ void Sema::AddInitializerToDecl(DeclPtrTy dcl, ExprArg init, bool DirectInit) {
       }
     }
   } else if (VDecl->isFileVarDecl()) {
-    if (VDecl->getStorageClass() == VarDecl::Extern)
+    if (VDecl->getStorageClass() == VarDecl::Extern && 
+        !getLangOptions().CPlusPlus)
       Diag(VDecl->getLocation(), diag::warn_extern_init);
     if (!VDecl->isInvalidDecl()) {
       InitializationSequence InitSeq(*this, Entity, Kind, &Init, 1);

test/SemaCXX/storage-class.cpp

@@ -0,0 +1,2 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+extern const int PR6495 = 42;