diff --git a/include/MSSA/SVFG.h b/include/MSSA/SVFG.h
index 55e56aeef..88bfb5d0c 100644
--- a/include/MSSA/SVFG.h
+++ b/include/MSSA/SVFG.h
@@ -105,7 +105,7 @@ class SVFG : public GenericSVFGGraphTy {
     StorePEToSVFGNodeMap storePEToSVFGNodeMap;	///< map store inst to store SVFGNode
     SVFGStat * stat;
     SVFGK kind;
-    MemSSA* mssa;
+    std::unique_ptr<MemSSA> mssa;
     PointerAnalysis* pta;
 
     /// Clean up memory
@@ -115,7 +115,7 @@ class SVFG : public GenericSVFGGraphTy {
     SVFG(SVFGK k = ORIGSVFGK);
 
     /// Start building SVFG
-    virtual void buildSVFG(MemSSA* m);
+    virtual void buildSVFG(std::unique_ptr<MemSSA> m);
 
 public:
     /// Destructor
@@ -133,9 +133,13 @@ class SVFG : public GenericSVFGGraphTy {
         return PAG::getPAG();
     }
 
+    inline MemSSA* getMSSA() {
+      return mssa.get();
+    };
+
     /// Clear MSSA
     inline void clearMSSA() {
-        mssa = NULL;
+        mssa.reset();
     }
 
     /// Get SVFG kind
diff --git a/include/MSSA/SVFGBuilder.h b/include/MSSA/SVFGBuilder.h
index c28935f76..dbfa271ef 100644
--- a/include/MSSA/SVFGBuilder.h
+++ b/include/MSSA/SVFGBuilder.h
@@ -95,7 +95,7 @@ class SVFGBuilder {
     /// We start from here
     virtual bool build(SVFG* graph,BVDataPTAImpl* pta);
     /// Can be rewritten by subclasses
-    virtual void createSVFG(MemSSA* mssa, SVFG* graph);
+    virtual void createSVFG(std::unique_ptr<MemSSA> mssa, SVFG* graph);
     /// Release global SVFG
     virtual void releaseMemory(SVFG* graph);
     /// Update call graph using pre-analysis points-to results
diff --git a/include/MSSA/SVFGOPT.h b/include/MSSA/SVFGOPT.h
index 28a1df4f2..34ed28517 100644
--- a/include/MSSA/SVFGOPT.h
+++ b/include/MSSA/SVFGOPT.h
@@ -81,8 +81,8 @@ class SVFGOPT : public SVFG {
         return g->getKind() == OPTSVFGK;
     }
 protected:
-    virtual inline void buildSVFG(MemSSA* m) {
-        SVFG::buildSVFG(m);
+    virtual inline void buildSVFG(std::unique_ptr<MemSSA> m) {
+        SVFG::buildSVFG(std::move(m));
 
         dump("SVFG_before_opt");
 
diff --git a/include/SABER/SaberSVFGBuilder.h b/include/SABER/SaberSVFGBuilder.h
index 5db948e42..c9a6816e6 100644
--- a/include/SABER/SaberSVFGBuilder.h
+++ b/include/SABER/SaberSVFGBuilder.h
@@ -55,7 +55,7 @@ class SaberSVFGBuilder : public SVFGBuilder {
     }
 protected:
     /// Re-write create SVFG method
-    virtual void createSVFG(MemSSA* mssa, SVFG* graph);
+    virtual void createSVFG(std::unique_ptr<MemSSA> mssa, SVFG* graph);
 
 private:
     /// Remove direct value-flow edge to a dereference point for Saber source-sink memory error detection
diff --git a/lib/MSSA/SVFG.cpp b/lib/MSSA/SVFG.cpp
index aba4e5187..6da6544ab 100644
--- a/lib/MSSA/SVFG.cpp
+++ b/lib/MSSA/SVFG.cpp
@@ -43,7 +43,7 @@ static cl::opt<bool> DumpVFG("dump-svfg", cl::init(false),
 /*!
  * Constructor
  */
-SVFG::SVFG(SVFGK k): totalSVFGNode(0), kind(k),mssa(NULL),pta(NULL) {
+SVFG::SVFG(SVFGK k): totalSVFGNode(0), kind(k),pta(NULL) {
     stat = new SVFGStat(this);
 }
 
@@ -53,7 +53,7 @@ SVFG::SVFG(SVFGK k): totalSVFGNode(0), kind(k),mssa(NULL),pta(NULL) {
 void SVFG::destroy() {
     delete stat;
     stat = NULL;
-    mssa = NULL;
+    mssa.reset();
     pta = NULL;
 }
 
@@ -66,9 +66,9 @@ void SVFG::destroy() {
  *    a) between two statements (PAGEdges)
  *    b) between two memory SSA operators (MSSAPHI MSSAMU and MSSACHI)
  */
-void SVFG::buildSVFG(MemSSA* m) {
-    mssa = m;
-    pta = m->getPTA();
+void SVFG::buildSVFG(std::unique_ptr<MemSSA> m) {
+    mssa = std::move(m);
+    pta = mssa->getPTA();
     stat->startClk();
     DBOUT(DGENERAL, outs() << pasMsg("\tCreate SVFG Top Level Node\n"));
 
diff --git a/lib/MSSA/SVFGBuilder.cpp b/lib/MSSA/SVFGBuilder.cpp
index 7ea07753e..d89903f3f 100644
--- a/lib/MSSA/SVFGBuilder.cpp
+++ b/lib/MSSA/SVFGBuilder.cpp
@@ -45,10 +45,10 @@ SVFGOPT* SVFGBuilder::globalSvfg = NULL;
 /*!
  * Create SVFG
  */
-void SVFGBuilder::createSVFG(MemSSA* mssa, SVFG* graph) {
+void SVFGBuilder::createSVFG(std::unique_ptr<MemSSA> mssa, SVFG* graph) {
     svfg = graph;
-    svfg->buildSVFG(mssa);
-    if(mssa->getPTA()->printStat())
+    svfg->buildSVFG(std::move(mssa));
+    if(svfg->getMSSA()->getPTA()->printStat())
         svfg->performStat();
     svfg->dump("FS_SVFG");
 }
@@ -85,7 +85,7 @@ void SVFGBuilder::releaseMemory(SVFG* vfg) {
  */
 bool SVFGBuilder::build(SVFG* graph,BVDataPTAImpl* pta) {
 
-    MemSSA mssa(pta);
+    auto mssa = llvm::make_unique<MemSSA>(pta);
 
     DBOUT(DGENERAL, outs() << pasMsg("Build Memory SSA \n"));
 
@@ -102,20 +102,22 @@ bool SVFGBuilder::build(SVFG* graph,BVDataPTAImpl* pta) {
         dt.recalculate(fun);
         df.runOnDT(dt);
 
-        mssa.buildMemSSA(fun, &df, &dt);
+        mssa->buildMemSSA(fun, &df, &dt);
     }
 
-    mssa.performStat();
-    mssa.dumpMSSA();
+    mssa->performStat();
+    mssa->dumpMSSA();
 
     DBOUT(DGENERAL, outs() << pasMsg("Build Sparse Value-Flow Graph \n"));
 
-    createSVFG(&mssa, graph);
+    createSVFG(std::move(mssa), graph);
 
     if(SVFGWithIndirectCall || SVFGWithIndCall)
-        updateCallGraph(mssa.getPTA());
+        updateCallGraph(graph->getMSSA()->getPTA());
 
-    releaseMemory(graph);
+    // Graph will release mssa either on request or
+    // when it itself is deleted.
+    // releaseMemory(graph);
 
     return false;
 }
diff --git a/lib/SABER/SaberSVFGBuilder.cpp b/lib/SABER/SaberSVFGBuilder.cpp
index a96214aaa..cd3ef5063 100644
--- a/lib/SABER/SaberSVFGBuilder.cpp
+++ b/lib/SABER/SaberSVFGBuilder.cpp
@@ -34,11 +34,11 @@
 using namespace llvm;
 using namespace analysisUtil;
 
-void SaberSVFGBuilder::createSVFG(MemSSA* mssa, SVFG* graph) {
+void SaberSVFGBuilder::createSVFG(std::unique_ptr<MemSSA> mssa, SVFG* graph) {
 
     svfg = graph;
-    svfg->buildSVFG(mssa);
-    BVDataPTAImpl* pta = mssa->getPTA();
+    svfg->buildSVFG(std::move(mssa));
+    BVDataPTAImpl* pta = svfg->getMSSA()->getPTA();
     DBOUT(DGENERAL, outs() << pasMsg("\tCollect Global Variables\n"));
 
     collectGlobals(pta);
diff --git a/lib/WPA/WPAPass.cpp b/lib/WPA/WPAPass.cpp
index 0dd13d1aa..1d560195b 100644
--- a/lib/WPA/WPAPass.cpp
+++ b/lib/WPA/WPAPass.cpp
@@ -129,7 +129,7 @@ void WPAPass::runPointerAnalysis(llvm::Module& module, u32_t kind)
     if (anderSVFG) {
         SVFGBuilder memSSA(true);
         SVFG *svfg = memSSA.buildSVFG((BVDataPTAImpl*)_pta);
-        svfg->dump("ander_svfg", true /* simple */);
+        svfg->dump("ander_svfg");
     }
 }