diff --git a/lib/Module/InstrumentLegacy.cpp b/lib/Module/InstrumentLegacy.cpp
index 9d7db4771a..0a05a40572 100644
--- a/lib/Module/InstrumentLegacy.cpp
+++ b/lib/Module/InstrumentLegacy.cpp
@@ -91,7 +91,7 @@ void klee::checkModule(bool DontVerify, llvm::Module *module) {
 
 void klee::optimiseAndPrepare(bool OptimiseKLEECall, bool Optimize,
                               bool Simplify, bool WithFPRuntime,
-                              SwitchImplType SwitchType, std::string EntryPoint,
+                              SwitchImplType SwitchType, const std::string &EntryPoint,
                               llvm::ArrayRef<const char *> preservedFunctions,
                               llvm::Module *module) {
   // Preserve all functions containing klee-related function calls from being
diff --git a/lib/Module/ModuleHelper.h b/lib/Module/ModuleHelper.h
index 89398adadf..d31a991347 100644
--- a/lib/Module/ModuleHelper.h
+++ b/lib/Module/ModuleHelper.h
@@ -22,7 +22,7 @@ enum class SwitchImplType {
 
 void optimiseAndPrepare(bool OptimiseKLEECall, bool Optimize, bool Simplify,
                         bool WithFPRuntime, SwitchImplType SwitchType,
-                        std::string EntryPoint,
+                        const std::string &EntryPoint,
                         llvm::ArrayRef<const char *> preservedFunctions,
                         llvm::Module *module);
 void checkModule(bool DontVerfify, llvm::Module *module);