More encapsulation work.

Use the AttributeSet when we're talking about more than one attribute. Add a
function that adds a single attribute. No functionality change intended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173196 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/Function.cpp

@@ -250,7 +250,9 @@ void Function::dropAllReferences() {
 
 void Function::addAttribute(unsigned i, Attribute attr) {
   AttributeSet PAL = getAttributes();
-  PAL = PAL.addAttr(getContext(), i, attr);
+  AttrBuilder B(attr);
+  PAL = PAL.addAttributes(getContext(), i,
+                          AttributeSet::get(getContext(), i, B));
   setAttributes(PAL);
 }