rocr: Fixed inefficient copy operations

Changed variable assignments to use std::move() where appropriate.
Changed function headers to pass string arguments by reference where appropriate.

Signed-off-by: Alysa Liu <Alysa.Liu@amd.com>


[ROCm/ROCR-Runtime commit: ae6851dbb4]

projects/rocr-runtime/runtime/hsa-runtime/core/driver/kfd/amd_kfd_driver.cpp

@@ -83,8 +83,8 @@ __forceinline uint64_t drm_perm(hsa_access_permission_t perm) {
 
 } // namespace
 
-KfdDriver::KfdDriver(std::string devnode_name)
-    : core::Driver(core::DriverType::KFD, devnode_name) {}
+KfdDriver::KfdDriver(std::string& devnode_name)
+    : core::Driver(core::DriverType::KFD, std::move(devnode_name)) {}
 
 hsa_status_t KfdDriver::Init() {
   HSAKMT_STATUS ret =
@@ -128,7 +128,8 @@ hsa_status_t KfdDriver::ShutDown() {
 }
 
 hsa_status_t KfdDriver::DiscoverDriver(std::unique_ptr<core::Driver>& driver) {
-  auto tmp_driver = std::unique_ptr<core::Driver>(new KfdDriver("/dev/kfd"));
+  std::string devnode("/dev/kfd");
+  auto tmp_driver = std::unique_ptr<core::Driver>(new KfdDriver(devnode));
 
   if (tmp_driver->Open() == HSA_STATUS_SUCCESS) {
     driver = std::move(tmp_driver);

projects/rocr-runtime/runtime/hsa-runtime/core/inc/amd_hsa_code.hpp

@@ -220,7 +220,7 @@ namespace code {
       void PrintRelocationData(std::ostream& out, RelocationSection* section);
       void PrintSymbol(std::ostream& out, Symbol* sym);
       void PrintDisassembly(std::ostream& out, const unsigned char *isa, size_t size, uint32_t isa_offset = 0);
-      std::string MangleSymbolName(const std::string& module_name, const std::string symbol_name);
+      std::string MangleSymbolName(const std::string& module_name, const std::string& symbol_name);
       bool ElfImageError();
 
     public:

projects/rocr-runtime/runtime/hsa-runtime/core/inc/amd_kfd_driver.h

@@ -69,7 +69,7 @@ namespace AMD {
 /// and more.
 class KfdDriver final : public core::Driver {
 public:
-  KfdDriver(std::string devnode_name);
+  KfdDriver(std::string& devnode_name);
 
   /// @brief Determine of the KFD is present on the system and attemp to open it if found.
   ///

projects/rocr-runtime/runtime/hsa-runtime/libamdhsacode/amd_hsa_code.cpp

@@ -175,7 +175,7 @@ namespace code {
     std::string Symbol::GetSymbolName() const {
       std::string FullName = Name();
       return FullName.rfind(":") != std::string::npos ?
-        std::move(FullName.substr(FullName.rfind(":") + 1)) : std::move(FullName);
+        FullName.substr(FullName.rfind(":") + 1) : std::move(FullName);
     }
 
     hsa_code_symbol_t Symbol::ToHandle(Symbol* sym)
@@ -920,7 +920,10 @@ namespace code {
 
     hsa_status_t AmdHsaCode::GetSymbol(const char *module_name, const char *symbol_name, hsa_code_symbol_t *s)
     {
-      std::string mname = MangleSymbolName(module_name ? module_name : "", symbol_name);
+      std::string mname = MangleSymbolName(
+        std::string(module_name ? module_name : ""),
+        std::string(symbol_name)
+      );
       for (Symbol* sym : symbols) {
         if (sym->Name() == mname) {
           *s = Symbol::ToHandle(sym);
@@ -1729,10 +1732,10 @@ namespace code {
       out << std::dec;
     }
 
-    std::string AmdHsaCode::MangleSymbolName(const std::string& module_name, const std::string symbol_name)
+    std::string AmdHsaCode::MangleSymbolName(const std::string& module_name, const std::string& symbol_name)
     {
       if (module_name.empty()) {
-        return std::move(symbol_name);
+        return symbol_name;
       } else {
         return module_name + "::" + symbol_name;
       }