diff --git a/include/llvm/DebugInfo.h b/include/llvm/DebugInfo.h
index 74416db2175..b02446abbbf 100644
--- a/include/llvm/DebugInfo.h
+++ b/include/llvm/DebugInfo.h
@@ -323,6 +323,7 @@ namespace llvm {
 
     DIArray getTypeArray() const { return getFieldAs<DIArray>(10); }
     void setTypeArray(DIArray Elements, DIArray TParams = DIArray());
+    void addMember(DISubprogram S);
     unsigned getRunTimeLang() const { return getUnsignedField(11); }
     DICompositeType getContainingType() const {
       return getFieldAs<DICompositeType>(12);
diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index fc9324949d0..0f7ddb5961c 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -647,6 +647,19 @@ void DICompositeType::setTypeArray(DIArray Elements, DIArray TParams) {
   DbgNode = N;
 }
 
+void DICompositeType::addMember(DISubprogram S) {
+  SmallVector<llvm::Value *, 16> M;
+  DIArray OrigM = getTypeArray();
+  unsigned Elements = OrigM.getNumElements();
+  if (Elements == 1 && !OrigM.getElement(0))
+    Elements = 0;
+  M.reserve(Elements + 1);
+  for (unsigned i = 0; i != Elements; ++i)
+    M.push_back(OrigM.getElement(i));
+  M.push_back(S);
+  setTypeArray(DIArray(MDNode::get(DbgNode->getContext(), M)));
+}
+
 /// \brief Set the containing type.
 void DICompositeType::setContainingType(DICompositeType ContainingType) {
   TrackingVH<MDNode> N(*this);