Pass strings by const reference

src/ast/codegen_llvm.cpp

@@ -1141,7 +1141,7 @@ void CodegenLLVM::visit(Program &program)
     probe->accept(*this);
 }
 
-int CodegenLLVM::getNextIndexForProbe(std::string probe_name) {
+int CodegenLLVM::getNextIndexForProbe(const std::string &probe_name) {
   if (next_probe_index_.count(probe_name) == 0)
     next_probe_index_[probe_name] = 1;
   int index = next_probe_index_[probe_name];
@@ -1149,7 +1149,7 @@ int CodegenLLVM::getNextIndexForProbe(std::string probe_name) {
   return index;
 }
 
-std::string CodegenLLVM::getSectionNameForProbe(std::string probe_name, int index) {
+std::string CodegenLLVM::getSectionNameForProbe(const std::string &probe_name, int index) {
   return "s_" + probe_name + "_" + std::to_string(index);
 }
 

src/ast/codegen_llvm.h

@@ -49,8 +49,8 @@ public:
   void visit(Program &program) override;
   AllocaInst *getMapKey(Map &map);
   AllocaInst *getHistMapKey(Map &map, Value *log2);
-  int         getNextIndexForProbe(std::string probe_name);
-  std::string getSectionNameForProbe(std::string probe_name, int index);
+  int         getNextIndexForProbe(const std::string &probe_name);
+  std::string getSectionNameForProbe(const std::string &probe_name, int index);
   Value      *createLogicalAnd(Binop &binop);
   Value      *createLogicalOr(Binop &binop);
 

src/clang_parser.cpp

@@ -106,7 +106,7 @@ static bool is_dir(const std::string& path)
   return S_ISDIR(buf.st_mode);
 }
 
-static std::pair<bool, std::string> get_kernel_path_info(const std::string kdir)
+static std::pair<bool, std::string> get_kernel_path_info(const std::string &kdir)
 {
   if (is_dir(kdir + "/build") && is_dir(kdir + "/source"))
     return std::make_pair(true, "source");