diff --git a/libcextract/Closure.hh b/libcextract/Closure.hh
index e4a364c..e0953eb 100644
--- a/libcextract/Closure.hh
+++ b/libcextract/Closure.hh
@@ -132,10 +132,10 @@ class ClosureSet
 class DeclClosureVisitor : public RecursiveASTVisitor<DeclClosureVisitor>
 {
   public:
-  DeclClosureVisitor(ASTUnit *ast, EnumConstantTable &table)
+  DeclClosureVisitor(ASTUnit *ast)
     : RecursiveASTVisitor(),
       AST(ast),
-      EnumTable(table)
+      EnumTable(ast)
   {
   }
 
@@ -520,7 +520,7 @@ class DeclClosureVisitor : public RecursiveASTVisitor<DeclClosureVisitor>
                                  std::unordered_set<std::string> *matched_names = nullptr);
 
   private:
-  
+
   /** The ASTUnit object.  */
   ASTUnit *AST;
 
@@ -533,7 +533,7 @@ class DeclClosureVisitor : public RecursiveASTVisitor<DeclClosureVisitor>
 
   /** The table maping EnumConstantDecl to its original EnumDecl, used to find
       out where a certain EnumConstantDecl was defined.  */
-  EnumConstantTable &EnumTable;
+  EnumConstantTable EnumTable;
 
   /** The set of all analyzed Decls.  */
   std::unordered_set<Decl *> AnalyzedDecls;
diff --git a/libcextract/FunctionDepsFinder.cpp b/libcextract/FunctionDepsFinder.cpp
index 6f93755..c9fcabe 100644
--- a/libcextract/FunctionDepsFinder.cpp
+++ b/libcextract/FunctionDepsFinder.cpp
@@ -24,10 +24,9 @@
 /** FunctionDependencyFinder class methods implementation.  */
 FunctionDependencyFinder::FunctionDependencyFinder(PassManager::Context *ctx)
     : AST(ctx->AST.get()),
-      EnumTable(AST),
       IT(AST, ctx->IncExpansionPolicy, ctx->HeadersToExpand),
       KeepIncludes(ctx->KeepIncludes),
-      Visitor(AST, EnumTable)
+      Visitor(AST)
 {
 }
 
diff --git a/libcextract/FunctionDepsFinder.hh b/libcextract/FunctionDepsFinder.hh
index 3f662cb..97bab8c 100644
--- a/libcextract/FunctionDepsFinder.hh
+++ b/libcextract/FunctionDepsFinder.hh
@@ -82,10 +82,6 @@ class FunctionDependencyFinder
     /** The AST that are being used in our analysis.  */
     ASTUnit* AST;
 
-    /** Object holding information about constant enum symbols and a mapping to
-        they original enum object.  */
-    EnumConstantTable EnumTable;
-
     /* Tree of #includes.  */
     IncludeTree IT;
 
diff --git a/libcextract/Passes.cpp b/libcextract/Passes.cpp
index d347fc4..86361d6 100644
--- a/libcextract/Passes.cpp
+++ b/libcextract/Passes.cpp
@@ -434,7 +434,9 @@ class FunctionExternalizerPass : public Pass
       /* Issue externalization.  */
       SymbolExternalizer externalizer(ctx->AST.get(), ctx->IA, ctx->Ibt,
                                       ctx->AllowLateExternalizations,
-                                      ctx->PatchObject, ctx->DumpPasses);
+                                      ctx->PatchObject,
+                                      ctx->FuncExtractNames,
+                                      ctx->DumpPasses);
       if (ctx->RenameSymbols)
         /* The FuncExtractNames will be modified, as the function will be renamed.  */
         externalizer.Externalize_Symbols(ctx->Externalize, ctx->FuncExtractNames);
diff --git a/libcextract/SymbolExternalizer.cpp b/libcextract/SymbolExternalizer.cpp
index 0f82c1d..9171188 100644
--- a/libcextract/SymbolExternalizer.cpp
+++ b/libcextract/SymbolExternalizer.cpp
@@ -19,6 +19,7 @@
 #include "ClangCompat.hh"
 #include "LLVMMisc.hh"
 #include "IntervalTree.hh"
+#include "Closure.hh"
 
 #include <unordered_set>
 #include <iostream>
@@ -205,9 +206,20 @@ class ExternalizerVisitor: public RecursiveASTVisitor<ExternalizerVisitor>
     if (sym == nullptr || !sym->Done)
       return VISITOR_CONTINUE;
 
-    /* If this is the first use of the symbol, then remember it.  */
+    /* Get the first effective use, which means an DeclRefExpr of a decl that
+       will not be removed by the Closure.  */
     if (sym->FirstUse == nullptr) {
-      sym->FirstUse = expr;
+      ClosureSet &closure = SE.ClosureVisitor.Get_Closure();
+      ASTUnit *ast = SE.AST;
+      SourceManager &sm = ast->getSourceManager();
+      SourceLocation loc = sm.getExpansionLoc(expr->getLocation());
+      Decl *topdecl = Get_Toplevel_Decl_At_Location(ast, loc);
+
+      /* If the declaration is reachable from the functions we want to extract,
+         then we mark it as FirstUse.  */
+      if (closure.Is_Decl_Marked(topdecl)) {
+        sym->FirstUse = expr;
+      }
     }
 
     /* We must be careful to ensure that the reference we got is actually
@@ -787,6 +799,12 @@ void SymbolExternalizer::Compute_SymbolsMap_Late_Insert_Locations(std::vector<Sy
   for (auto array_it = array.begin(); array_it != array.end(); ++array_it) {
     SymbolUpdateStatus *sym = *array_it;
     DeclRefExpr *first_use = sym->FirstUse;
+
+    /* In case FirstUse is nullptr, then there is nothing to externalize
+       because it will be removed by the ClosurePass.  */
+    if (first_use == nullptr)
+      continue;
+
     SourceLocation loc_1stuse = SM.getExpansionLoc(first_use->getLocation());
 
     Decl *topdecl = Get_Toplevel_Decl_At_Location(AST, loc_1stuse);
diff --git a/libcextract/SymbolExternalizer.hh b/libcextract/SymbolExternalizer.hh
index c71efcd..fff6ec2 100644
--- a/libcextract/SymbolExternalizer.hh
+++ b/libcextract/SymbolExternalizer.hh
@@ -17,6 +17,7 @@
 
 #include "MacroWalker.hh"
 #include "InlineAnalysis.hh"
+#include "Closure.hh"
 
 #include <clang/Tooling/Tooling.h>
 #include <clang/Rewrite/Core/Rewriter.h>
@@ -96,7 +97,7 @@ struct SymbolUpdateStatus
      attempt of externalize an symbol which was removed by the ClosurePass.  */
   inline bool Is_Used(void)
   {
-    return OldDecl && NewDecl;
+    return OldDecl && NewDecl && FirstUse;
   }
 
   void Dump(SourceManager &SM)
@@ -284,6 +285,7 @@ class SymbolExternalizer
   public:
   SymbolExternalizer(ASTUnit *ast, InlineAnalysis &ia, bool ibt,
                      bool allow_late_externalize, std::string patch_object,
+                     const std::vector<std::string> &functions_to_extract,
                      bool dump = false)
     : AST(ast),
       MW(ast->getPreprocessor()),
@@ -292,8 +294,10 @@ class SymbolExternalizer
       Ibt(ibt),
       AllowLateExternalization(allow_late_externalize),
       PatchObject(patch_object),
-      SymbolsMap({})
+      SymbolsMap({}),
+      ClosureVisitor(ast)
   {
+    ClosureVisitor.Compute_Closure_Of_Symbols(functions_to_extract);
   }
 
   friend class ExternalizerVisitor;
@@ -387,4 +391,7 @@ class SymbolExternalizer
 
   /** Symbols and its externalization type */
   llvm::StringMap<SymbolUpdateStatus> SymbolsMap;
+
+  /* ClosureVisitor to compute the closure.  */
+  DeclClosureVisitor ClosureVisitor;
 };