Handle string attributes in the AttrBuilder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174834 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index 04e95ef..e64603c 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -879,7 +879,11 @@
 }
 
 AttrBuilder &AttrBuilder::addAttribute(Attribute Attr) {
-  // FIXME: Handle string attributes.
+  if (Attr.isStringAttribute()) {
+    addAttribute(Attr.getKindAsString(), Attr.getValueAsString());
+    return *this;
+  }
+
   Attribute::AttrKind Kind = Attr.getKindAsEnum();
   Attrs.insert(Kind);