[objcmt] Don't migrate to subscripting syntax if the required methods have not
been declared on NSArray/NSDictionary.

rdar://11581975

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@157951 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/NSAPI.cpp b/lib/AST/NSAPI.cpp
index 72251d3..39077d1 100644
--- a/lib/AST/NSAPI.cpp
+++ b/lib/AST/NSAPI.cpp
@@ -399,3 +399,15 @@
 
   return false;
 }
+
+Selector NSAPI::getOrInitSelector(ArrayRef<StringRef> Ids,
+                                  Selector &Sel) const {
+  if (Sel.isNull()) {
+    SmallVector<IdentifierInfo *, 4> Idents;
+    for (ArrayRef<StringRef>::const_iterator
+           I = Ids.begin(), E = Ids.end(); I != E; ++I)
+      Idents.push_back(&Ctx.Idents.get(*I));
+    Sel = Ctx.Selectors.getSelector(Idents.size(), Idents.data());
+  }
+  return Sel;
+}