Add a new utility function to return the device info as a C string object. (#620)

* Add a new utility function to return the device info as a C string object.

* Add a helper to convert a C++ string to and a C string.

Author: Diptorup Deb

dpctl-capi/helper/include/dpctl_string_utils.hpp

@@ -0,0 +1,61 @@
+//===--- dpctl_string_utils.hpp - C++ to C string converted     -*-C++-*- ===//
+//
+//                      Data Parallel Control (dpctl)
+//
+// Copyright 2020-2021 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Helper function to convert a C++ string to a C string.
+//===----------------------------------------------------------------------===//
+#include <cstring>
+#include <iostream>
+#include <string>
+
+#pragma once
+
+namespace dpctl
+{
+namespace helper
+{
+/*!
+ * @brief Convert a C++ std::string to a const char* and return the string to
+ * caller.
+ *
+ * @param    str            A C++ string that has to be converted to a C string.
+ * @return A const char* string representation of the C++ string.
+ */
+static inline __dpctl_give const char *
+cstring_from_string(const std::string &str)
+{
+    char *cstr = nullptr;
+    try {
+        auto cstr_len = str.length() + 1;
+        cstr = new char[cstr_len];
+#ifdef _WIN32
+        strncpy_s(cstr, cstr_len, str.c_str(), cstr_len);
+#else
+        std::strncpy(cstr, str.c_str(), cstr_len);
+#endif
+    } catch (std::bad_alloc const &ba) {
+        // \todo log error
+        std::cerr << ba.what() << '\n';
+    }
+
+    return cstr;
+}
+} // namespace helper
+} // namespace dpctl

dpctl-capi/include/dpctl_sycl_device_manager.h

@@ -76,6 +76,22 @@ DPCTL_API
 __dpctl_give DPCTLDeviceVectorRef
 DPCTLDeviceMgr_GetDevices(int device_identifier);
 
+/*!
+ * @brief Returns a set of device info attributes as a string.
+ *
+ * @param    DRef           Opaque pointer to a ``sycl::device``
+ * @return   A formatted C string capturing the following attributes:
+ *             - device name
+ *             - driver version
+ *             - vendor
+ *             - profiler support
+ *             - oneapi filter string
+ * @ingroup DeviceManager
+ */
+DPCTL_API
+__dpctl_give const char *
+DPCTLDeviceMgr_GetDeviceInfoStr(__dpctl_keep const DPCTLSyclDeviceRef DRef);
+
 /*!
  * @brief Returns an index on the given device in the vector returned by
  * #DPCTLDeviceMgr_GetDevices if found, -1 otherwise.
@@ -91,6 +107,7 @@ DPCTLDeviceMgr_GetDevices(int device_identifier);
  * @return   If found, returns the position of the given device in the
  * vector that would be returned by #DPCTLDeviceMgr_GetDevices if called
  * with the same device_identifier argument.
+ * @ingroup DeviceManager
  */
 DPCTL_API
 int DPCTLDeviceMgr_GetPositionInDevices(__dpctl_keep DPCTLSyclDeviceRef DRef,
@@ -122,6 +139,7 @@ DPCTLDeviceMgr_GetCachedContext(__dpctl_keep const DPCTLSyclDeviceRef DRef);
  *                             the enum values or a bitwise OR-ed combination.
  * @return   The number of available devices satisfying the condition specified
  * by the device_identifier bit flag.
+ * @ingroup DeviceManager
  */
 DPCTL_API
 size_t DPCTLDeviceMgr_GetNumDevices(int device_identifier);
@@ -131,6 +149,7 @@ size_t DPCTLDeviceMgr_GetNumDevices(int device_identifier);
  * currently supported by dpctl.
  *
  * @param    DRef           A #DPCTLSyclDeviceRef opaque pointer.
+ * @ingroup DeviceManager
  */
 DPCTL_API
 void DPCTLDeviceMgr_PrintDeviceInfo(__dpctl_keep const DPCTLSyclDeviceRef DRef);

dpctl-capi/source/dpctl_service.cpp

@@ -26,25 +26,13 @@
 #include "dpctl_service.h"
 #include "Config/dpctl_config.h"
 
+#include "../helper/include/dpctl_string_utils.hpp"
 #include <algorithm>
 #include <cstring>
 #include <iostream>
 
 __dpctl_give const char *DPCTLService_GetDPCPPVersion(void)
 {
     std::string version = DPCTL_DPCPP_VERSION;
-    char *version_cstr = nullptr;
-    try {
-        auto cstr_len = version.length() + 1;
-        version_cstr = new char[cstr_len];
-#ifdef _WIN32
-        strncpy_s(version_cstr, cstr_len, version.c_str(), cstr_len);
-#else
-        std::strncpy(version_cstr, version.c_str(), cstr_len);
-#endif
-    } catch (std::bad_alloc const &ba) {
-        // \todo log error
-        std::cerr << ba.what() << '\n';
-    }
-    return version_cstr;
+    return dpctl::helper::cstring_from_string(version);
 }

dpctl-capi/source/dpctl_sycl_device_interface.cpp

@@ -25,6 +25,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "dpctl_sycl_device_interface.h"
+#include "../helper/include/dpctl_string_utils.hpp"
 #include "../helper/include/dpctl_utils_helper.h"
 #include "Support/CBindingWrapping.h"
 #include "dpctl_sycl_device_manager.h"
@@ -308,21 +309,12 @@ DPCTLDevice_GetPlatform(__dpctl_keep const DPCTLSyclDeviceRef DRef)
 __dpctl_give const char *
 DPCTLDevice_GetName(__dpctl_keep const DPCTLSyclDeviceRef DRef)
 {
-    char *cstr_name = nullptr;
+    const char *cstr_name = nullptr;
     auto D = unwrap(DRef);
     if (D) {
         try {
             auto name = D->get_info<info::device::name>();
-            auto cstr_len = name.length() + 1;
-            cstr_name = new char[cstr_len];
-#ifdef _WIN32
-            strncpy_s(cstr_name, cstr_len, name.c_str(), cstr_len);
-#else
-            std::strncpy(cstr_name, name.c_str(), cstr_len);
-#endif
-        } catch (std::bad_alloc const &ba) {
-            // \todo log error
-            std::cerr << ba.what() << '\n';
+            cstr_name = dpctl::helper::cstring_from_string(name);
         } catch (runtime_error const &re) {
             // \todo log error
             std::cerr << re.what() << '\n';
@@ -334,21 +326,12 @@ DPCTLDevice_GetName(__dpctl_keep const DPCTLSyclDeviceRef DRef)
 __dpctl_give const char *
 DPCTLDevice_GetVendor(__dpctl_keep const DPCTLSyclDeviceRef DRef)
 {
-    char *cstr_vendor = nullptr;
+    const char *cstr_vendor = nullptr;
     auto D = unwrap(DRef);
     if (D) {
         try {
             auto vendor = D->get_info<info::device::vendor>();
-            auto cstr_len = vendor.length() + 1;
-            cstr_vendor = new char[cstr_len];
-#ifdef _WIN32
-            strncpy_s(cstr_vendor, cstr_len, vendor.c_str(), cstr_len);
-#else
-            std::strncpy(cstr_vendor, vendor.c_str(), cstr_len);
-#endif
-        } catch (std::bad_alloc const &ba) {
-            // \todo log error
-            std::cerr << ba.what() << '\n';
+            cstr_vendor = dpctl::helper::cstring_from_string(vendor);
         } catch (runtime_error const &re) {
             // \todo log error
             std::cerr << re.what() << '\n';
@@ -360,21 +343,12 @@ DPCTLDevice_GetVendor(__dpctl_keep const DPCTLSyclDeviceRef DRef)
 __dpctl_give const char *
 DPCTLDevice_GetDriverVersion(__dpctl_keep const DPCTLSyclDeviceRef DRef)
 {
-    char *cstr_driver = nullptr;
+    const char *cstr_driver = nullptr;
     auto D = unwrap(DRef);
     if (D) {
         try {
             auto driver = D->get_info<info::device::driver_version>();
-            auto cstr_len = driver.length() + 1;
-            cstr_driver = new char[cstr_len];
-#ifdef _WIN32
-            strncpy_s(cstr_driver, cstr_len, driver.c_str(), cstr_len);
-#else
-            std::strncpy(cstr_driver, driver.c_str(), cstr_len);
-#endif
-        } catch (std::bad_alloc const &ba) {
-            // \todo log error
-            std::cerr << ba.what() << '\n';
+            cstr_driver = dpctl::helper::cstring_from_string(driver);
         } catch (runtime_error const &re) {
             // \todo log error
             std::cerr << re.what() << '\n';

dpctl-capi/source/dpctl_sycl_device_manager.cpp

@@ -24,6 +24,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "dpctl_sycl_device_manager.h"
+#include "../helper/include/dpctl_string_utils.hpp"
 #include "../helper/include/dpctl_utils_helper.h"
 #include "Support/CBindingWrapping.h"
 #include "dpctl_sycl_enum_types.h"
@@ -45,7 +46,7 @@ DEFINE_SIMPLE_CONVERSION_FUNCTIONS(context, DPCTLSyclContextRef)
 /*
  * Helper function to print the metadata for a sycl::device.
  */
-void print_device_info(const device &Device)
+std::string get_device_info_str(const device &Device)
 {
     std::stringstream ss;
 
@@ -62,7 +63,7 @@ void print_device_info(const device &Device)
        << DPCTL_DeviceTypeToStr(Device.get_info<info::device::device_type>())
        << ":" << DPCTL_GetRelativeDeviceId(Device) << '\n';
 
-    std::cout << ss.str();
+    return ss.str();
 }
 
 struct DeviceCacheBuilder
@@ -169,6 +170,23 @@ DPCTLDeviceMgr_GetDevices(int device_identifier)
     return wrap(Devices);
 }
 
+__dpctl_give const char *
+DPCTLDeviceMgr_GetDeviceInfoStr(__dpctl_keep const DPCTLSyclDeviceRef DRef)
+{
+    const char *cstr_info = nullptr;
+    auto D = unwrap(DRef);
+    if (D) {
+        try {
+            auto infostr = get_device_info_str(*D);
+            cstr_info = dpctl::helper::cstring_from_string(infostr);
+        } catch (runtime_error const &re) {
+            // \todo log error
+            std::cerr << re.what() << '\n';
+        }
+    }
+    return cstr_info;
+}
+
 int DPCTLDeviceMgr_GetPositionInDevices(__dpctl_keep DPCTLSyclDeviceRef DRef,
                                         int device_identifier)
 {
@@ -227,7 +245,7 @@ void DPCTLDeviceMgr_PrintDeviceInfo(__dpctl_keep const DPCTLSyclDeviceRef DRef)
 {
     auto Device = unwrap(DRef);
     if (Device)
-        print_device_info(*Device);
+        std::cout << get_device_info_str(*Device);
     else
         std::cout << "Device is not valid (NULL). Cannot print device info.\n";
 }

dpctl-capi/source/dpctl_sycl_kernel_interface.cpp

@@ -25,6 +25,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "dpctl_sycl_kernel_interface.h"
+#include "../helper/include/dpctl_string_utils.hpp"
 #include "Support/CBindingWrapping.h"
 #include <CL/sycl.hpp> /* Sycl headers */
 
@@ -49,14 +50,7 @@ DPCTLKernel_GetFunctionName(__dpctl_keep const DPCTLSyclKernelRef Kernel)
     auto kernel_name = SyclKernel->get_info<info::kernel::function_name>();
     if (kernel_name.empty())
         return nullptr;
-    auto cstr_len = kernel_name.length() + 1;
-    auto cstr_name = new char[cstr_len];
-#ifdef _WIN32
-    strncpy_s(cstr_name, cstr_len, kernel_name.c_str(), cstr_len);
-#else
-    std::strncpy(cstr_name, kernel_name.c_str(), cstr_len);
-#endif
-    return cstr_name;
+    return dpctl::helper::cstring_from_string(kernel_name);
 }
 
 size_t DPCTLKernel_GetNumArgs(__dpctl_keep const DPCTLSyclKernelRef Kernel)