Cycles: Pass string by const reference rather than by value

Some of the functions might have been inlined, but others i don't see
how that was possible (don't think virtual functions can be inlined here).

In any case, better be explicitly optimal in the code.

6 files changed, 25 insertions, 20 deletions

diff --git a/intern/cycles/device/device_cpu.cpp b/intern/cycles/device/device_cpu.cpp
index a0cdec0951b..18112437b45 100644
--- a/intern/cycles/device/device_cpu.cpp
+++ b/intern/cycles/device/device_cpu.cpp
@@ -149,7 +149,8 @@ public:
 	                                            device_memory& use_queues_flag,
 	                                            device_memory& work_pool_wgs);
 
-	virtual SplitKernelFunction* get_split_kernel_function(string kernel_name, const DeviceRequestedFeatures&);
+	virtual SplitKernelFunction* get_split_kernel_function(const string& kernel_name,
+	                                                       const DeviceRequestedFeatures&);
 	virtual int2 split_kernel_local_size();
 	virtual int2 split_kernel_global_size(device_memory& kg, device_memory& data, DeviceTask *task);
 	virtual uint64_t state_buffer_size(device_memory& kg, device_memory& data, size_t num_threads);
@@ -932,7 +933,8 @@ bool CPUSplitKernel::enqueue_split_kernel_data_init(const KernelDimensions& dim,
 	return true;
 }
 
-SplitKernelFunction* CPUSplitKernel::get_split_kernel_function(string kernel_name, const DeviceRequestedFeatures&)
+SplitKernelFunction* CPUSplitKernel::get_split_kernel_function(const string& kernel_name,
+                                                               const DeviceRequestedFeatures&)
 {
 	CPUSplitKernelFunction *kernel = new CPUSplitKernelFunction(device);
 
diff --git a/intern/cycles/device/device_cuda.cpp b/intern/cycles/device/device_cuda.cpp
index 29fa08d94b1..3a29538aa13 100644
--- a/intern/cycles/device/device_cuda.cpp
+++ b/intern/cycles/device/device_cuda.cpp
@@ -105,7 +105,8 @@ public:
 	                                            device_memory& use_queues_flag,
 	                                            device_memory& work_pool_wgs);
 
-	virtual SplitKernelFunction* get_split_kernel_function(string kernel_name, const DeviceRequestedFeatures&);
+	virtual SplitKernelFunction* get_split_kernel_function(const string& kernel_name,
+	                                                       const DeviceRequestedFeatures&);
 	virtual int2 split_kernel_local_size();
 	virtual int2 split_kernel_global_size(device_memory& kg, device_memory& data, DeviceTask *task);
 };
@@ -2037,7 +2038,8 @@ bool CUDASplitKernel::enqueue_split_kernel_data_init(const KernelDimensions& dim
 	return !device->have_error();
 }
 
-SplitKernelFunction* CUDASplitKernel::get_split_kernel_function(string kernel_name, const DeviceRequestedFeatures&)
+SplitKernelFunction* CUDASplitKernel::get_split_kernel_function(const string& kernel_name,
+                                                                const DeviceRequestedFeatures&)
 {
 	CUfunction func;
 
diff --git a/intern/cycles/device/device_split_kernel.h b/intern/cycles/device/device_split_kernel.h
index 2bac1998cb7..9c42cb58520 100644
--- a/intern/cycles/device/device_split_kernel.h
+++ b/intern/cycles/device/device_split_kernel.h
@@ -125,7 +125,8 @@ public:
 	                                            device_memory& use_queues_flag,
 	                                            device_memory& work_pool_wgs) = 0;
 
-	virtual SplitKernelFunction* get_split_kernel_function(string kernel_name, const DeviceRequestedFeatures&) = 0;
+	virtual SplitKernelFunction* get_split_kernel_function(const string& kernel_name,
+	                                                       const DeviceRequestedFeatures&) = 0;
 	virtual int2 split_kernel_local_size() = 0;
 	virtual int2 split_kernel_global_size(device_memory& kg, device_memory& data, DeviceTask *task) = 0;
 };
diff --git a/intern/cycles/device/opencl/opencl.h b/intern/cycles/device/opencl/opencl.h
index 399fae9b42e..7da690904aa 100644
--- a/intern/cycles/device/opencl/opencl.h
+++ b/intern/cycles/device/opencl/opencl.h
@@ -84,7 +84,7 @@ public:
 	                                   string *error = NULL);
 	static bool device_version_check(cl_device_id device,
 	                                 string *error = NULL);
-	static string get_hardware_id(string platform_name,
+	static string get_hardware_id(const string& platform_name,
 	                              cl_device_id device_id);
 	static void get_usable_devices(vector<OpenCLPlatformDevice> *usable_devices,
 	                               bool force_all = false);
@@ -247,17 +247,17 @@ public:
 	public:
 		OpenCLProgram() : loaded(false), device(NULL) {}
 		OpenCLProgram(OpenCLDeviceBase *device,
-		              string program_name,
-		              string kernel_name,
-		              string kernel_build_options,
+		              const string& program_name,
+		              const string& kernel_name,
+		              const string& kernel_build_options,
 		              bool use_stdout = true);
 		~OpenCLProgram();
 
 		void add_kernel(ustring name);
 		void load();
 
-		bool is_loaded()    { return loaded; }
-		string get_log()    { return log; }
+		bool is_loaded() const { return loaded; }
+		const string& get_log() const { return log; }
 		void report_error();
 
 		cl_kernel operator()();
@@ -271,8 +271,8 @@ public:
 		bool load_binary(const string& clbin, const string *debug_src = NULL);
 		bool save_binary(const string& clbin);
 
-		void add_log(string msg, bool is_debug);
-		void add_error(string msg);
+		void add_log(const string& msg, bool is_debug);
+		void add_error(const string& msg);
 
 		bool loaded;
 		cl_program program;
diff --git a/intern/cycles/device/opencl/opencl_split.cpp b/intern/cycles/device/opencl/opencl_split.cpp
index 08b632ee9d3..73b8769d3cc 100644
--- a/intern/cycles/device/opencl/opencl_split.cpp
+++ b/intern/cycles/device/opencl/opencl_split.cpp
@@ -263,7 +263,7 @@ public:
 	explicit OpenCLSplitKernel(OpenCLDeviceSplitKernel *device) : DeviceSplitKernel(device), device(device) {
 	}
 
-	virtual SplitKernelFunction* get_split_kernel_function(string kernel_name,
+	virtual SplitKernelFunction* get_split_kernel_function(const string& kernel_name,
 	                                                       const DeviceRequestedFeatures& requested_features)
 	{
 		OpenCLSplitKernelFunction* kernel = new OpenCLSplitKernelFunction(device, cached_memory);
diff --git a/intern/cycles/device/opencl/opencl_util.cpp b/intern/cycles/device/opencl/opencl_util.cpp
index 8ba2a8e26da..0d34af3e040 100644
--- a/intern/cycles/device/opencl/opencl_util.cpp
+++ b/intern/cycles/device/opencl/opencl_util.cpp
@@ -241,9 +241,9 @@ string OpenCLCache::get_kernel_md5()
 }
 
 OpenCLDeviceBase::OpenCLProgram::OpenCLProgram(OpenCLDeviceBase *device,
-                                               string program_name,
-                                               string kernel_file,
-                                               string kernel_build_options,
+                                               const string& program_name,
+                                               const string& kernel_file,
+                                               const string& kernel_build_options,
                                                bool use_stdout)
  : device(device),
    program_name(program_name),
@@ -274,7 +274,7 @@ void OpenCLDeviceBase::OpenCLProgram::release()
 	}
 }
 
-void OpenCLDeviceBase::OpenCLProgram::add_log(string msg, bool debug)
+void OpenCLDeviceBase::OpenCLProgram::add_log(const string& msg, bool debug)
 {
 	if(!use_stdout) {
 		log += msg + "\n";
@@ -288,7 +288,7 @@ void OpenCLDeviceBase::OpenCLProgram::add_log(string msg, bool debug)
 	}
 }
 
-void OpenCLDeviceBase::OpenCLProgram::add_error(string msg)
+void OpenCLDeviceBase::OpenCLProgram::add_error(const string& msg)
 {
 	if(use_stdout) {
 		fprintf(stderr, "%s\n", msg.c_str());
@@ -707,7 +707,7 @@ bool OpenCLInfo::device_version_check(cl_device_id device,
 	return true;
 }
 
-string OpenCLInfo::get_hardware_id(string platform_name, cl_device_id device_id)
+string OpenCLInfo::get_hardware_id(const string& platform_name, cl_device_id device_id)
 {
 	if(platform_name == "AMD Accelerated Parallel Processing" || platform_name == "Apple") {
 		/* Use cl_amd_device_topology extension. */