Switched FormatAttr to using an IdentifierArgument instead of a StringArgument since that is a more accurate modeling.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189851 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index b603233..78942af 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -9755,7 +9755,8 @@
             FD->getParamDecl(FormatIdx)->getType()->isObjCObjectPointerType())
           fmt = "NSString";
         FD->addAttr(::new (Context) FormatAttr(FD->getLocation(), Context,
-                                               fmt, FormatIdx+1,
+                                               &Context.Idents.get(fmt),
+                                               FormatIdx+1,
                                                HasVAListArg ? 0 : FormatIdx+2));
       }
     }
@@ -9763,7 +9764,8 @@
                                              HasVAListArg)) {
      if (!FD->getAttr<FormatAttr>())
        FD->addAttr(::new (Context) FormatAttr(FD->getLocation(), Context,
-                                              "scanf", FormatIdx+1,
+                                              &Context.Idents.get("scanf"),
+                                              FormatIdx+1,
                                               HasVAListArg ? 0 : FormatIdx+2));
     }
 
@@ -9803,7 +9805,7 @@
     // target-specific builtins, perhaps?
     if (!FD->getAttr<FormatAttr>())
       FD->addAttr(::new (Context) FormatAttr(FD->getLocation(), Context,
-                                             "printf", 2,
+                                             &Context.Idents.get("printf"), 2,
                                              Name->isStr("vasprintf") ? 0 : 3));
   }