FlowSet abstract class is being created as a template that would be a

linkedlist to support different type of values(llvm). But there is some issue in the push_back function declaration. After doing changes, llvm is being built successfully but while using this in a pass an error is being thrown when trying to run the pass. Pass is being built successfully but while loading the pass using opt and running it with a program symbol lookup error is being thrown.
llvm · s-nil · Sep 9, 2019 · Sep 28, 2019 · Oct 3, 2019 · Sep 28, 2019
commit ef18c4029c01939e41c12000fc837c44428f9768
diff --git a/llvm/include/llvm/DataFlowAnalysis/FlowSet.h b/llvm/include/llvm/DataFlowAnalysis/FlowSet.h
@@ -0,0 +1,101 @@
+#ifndef LLVM_DFA_FLOWSET_H
+#define LLVM_DFA_FLOWSET_H
+#include <iostream>
+
+using namespace std;
+namespace llvm{
+
+template <typename T>
+class FlowSet
+{
+    class Node;
+
+public:
+    FlowSet<T>() noexcept
+    {
+	//m_spRoot = nullptr;
+    }
+
+    class Iterator;
+
+    Iterator begin()
+    {
+	return Iterator(m_spRoot);
+    }
+
+    Iterator end()
+    {
+	return Iterator(nullptr);
+    }
+
+    void push_back(T data);
+    //void traverse();
+
+    class Iterator
+    {
+    public:
+	Iterator() noexcept:
+	    m_pCurrentNode(m_spRoot){	}
+
+	Iterator(const Node* pNode) noexcept:
+	    m_pCurrentNode(pNode){  }
+
+	Iterator& operator=(Node* pNode)
+	{
+	    this->m_pCurrentNode = pNode;
+	    return *this;
+	}
+
+	Iterator& operator++()
+	{
+	    if(m_pCurrentNode)
+		m_pCurrentNode = m_pCurrentNode->pNext;
+	    return *this;
+	}
+
+	Iterator& operator++(int)
+	{
+	    Iterator it = *this;
+	    ++*this;
+	    return it;
+	}
+
+	Iterator& operator!=(const Iterator& it)
+	{
+	    return m_pCurrentNode != it.m_pCurrentNode;
+	}
+
+	int operator*()
+	{
+	    return m_pCurrentNode->data;
+	}
+    private:
+	const Node* m_pCurrentNode;
+    };
+
+private:
+    class Node
+    {
+	T data;
+	Node* pNext;
+
+	friend class FlowSet;
+    };
+
+    Node* getNode(T d)
+    {
+	Node* pTmp = new Node;
+	pTmp->data = d;
+	pTmp->pNext = nullptr;
+	return pTmp;
+    }
+    Node*& getRoot()
+    {
+	return m_spRoot;
+    }
+    static Node* m_spRoot;
+};
+
+}   // end namepspace llvm
+
+#endif	// LLVM_DFA_FLOWSET_H
diff --git a/llvm/lib/DataFlowAnalysis/FlowSet.cpp b/llvm/lib/DataFlowAnalysis/FlowSet.cpp
@@ -0,0 +1,25 @@
+#include "llvm/DataFlowAnalysis/FlowSet.h"
+
+using namespace llvm;
+
+template <typename T>
+typename FlowSet<T>::Node* FlowSet<T>::m_spRoot = nullptr;
+
+template <typename T>
+void FlowSet<T>::push_back(T data)
+{
+    Node* pTemp = getNode(data);
+    if(!getRoot())
+    {
+	getRoot() = pTemp;
+    }
+    else
+    {
+	Node* pC = getRoot();
+	while(pC->pNext)
+	{
+	    pC = pC->pNext;
+	}
+	pC->pNext = pTemp;
+    }
+}