使用原生Clang++编译SYCL程序遇interop_handler弃用警告的问询

问题场景 #

使用原生Clang++ 16编译极简SYCL代码时，出现了dpcpp编译不会产生的interop_handler弃用警告，担心是否会导致运行时异常，寻求解决办法。

触发警告的代码 #

#include <CL/sycl.hpp>
int main(){}

编译命令 #

clang++ -std=c++17 -I$INCLUDEDIR -c t.cpp

警告信息 #

In file included from t.cpp:1:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl.hpp:16:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/backend.hpp:18:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/backend_traits_opencl.hpp:26:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/queue.hpp:20:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/handler.hpp:14:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/cg.hpp:27:
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/cg_types.hpp:234:32: warning: 'interop_handler' is deprecated: interop_handler class is deprecated, use interop_handle instead with host-task [-Wdeprecated-declarations]
  std::function<void(cl::sycl::interop_handler)> MFunc;
                               ^
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/interop_handler.hpp:18:7: note: 'interop_handler' has been explicitly marked deprecated here
class __SYCL_DEPRECATED("interop_handler class is deprecated, use"
      ^
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/defines_elementary.hpp:45:38: note: expanded from macro '__SYCL_DEPRECATED'
#define __SYCL_DEPRECATED(message) [[deprecated(message)]]
                                     ^
In file included from t.cpp:1:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl.hpp:16:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/backend.hpp:18:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/backend_traits_opencl.hpp:26:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/queue.hpp:20:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/handler.hpp:14:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/cg.hpp:27:
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/cg_types.hpp:237:44: warning: 'interop_handler' is deprecated: interop_handler class is deprecated, use interop_handle instead with host-task [-Wdeprecated-declarations]
  InteropTask(std::function<void(cl::sycl::interop_handler)> Func)
                                           ^
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/interop_handler.hpp:18:7: note: 'interop_handler' has been explicitly marked deprecated here
class __SYCL_DEPRECATED("interop_handler class is deprecated, use"
      ^
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/defines_elementary.hpp:45:38: note: expanded from macro '__SYCL_DEPRECATED'
#define __SYCL_DEPRECATED(message) [[deprecated(message)]]
                                     ^
In file included from t.cpp:1:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl.hpp:16:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/backend.hpp:18:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/backend_traits_opencl.hpp:26:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/queue.hpp:20:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/handler.hpp:14:
In file included from /ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/cg.hpp:27:
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/cg_types.hpp:239:23: warning: 'interop_handler' is deprecated: interop_handler class is deprecated, use interop_handle instead with host-task [-Wdeprecated-declarations]
  void call(cl::sycl::interop_handler &h) { MFunc(h); }
                      ^
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/interop_handler.hpp:18:7: note: 'interop_handler' has been explicitly marked deprecated here
class __SYCL_DEPRECATED("interop_handler class is deprecated, use"
      ^
/ONE_API_2022.3/compiler/2022.2.0/linux/include/sycl/CL/sycl/detail/defines_elementary.hpp:45:38: note: expanded from macro '__SYCL_DEPRECATED'
#define __SYCL_DEPRECATED(message) [[deprecated(message)]]
                                     ^
3 warnings generated.

是否需要担忧？ #

• 这些警告来自SYCL标准库内部的弃用代码，并非你的业务代码问题，所以不会直接引发运行时异常。弃用标记仅表示该API会在未来版本中移除，当前版本仍能正常工作。
• dpcpp未触发警告，是因为Intel编译器默认屏蔽了库内部的弃用警告，或是其配套SYCL头文件做了特殊处理过滤了这类信息。

解决方法 #

1. 屏蔽特定弃用警告 #

编译时添加-Wno-deprecated-declarations参数，直接关闭弃用警告：

clang++ -std=c++17 -I$INCLUDEDIR -Wno-deprecated-declarations -c t.cpp

该方法不会影响你的业务代码中的弃用提示，仅屏蔽库内部的警告。

2. 使用版本匹配的SYCL实现 #

你当前使用的是Intel oneAPI 2022.3的SYCL头文件，与原生Clang 16存在版本兼容性问题。建议：

• 直接使用原生Clang 16自带的SYCL支持：编译时添加-fsycl参数，无需额外引入Intel头文件，命令为clang++ -std=c++17 -fsycl -c t.cpp
• 升级Intel oneAPI到新版本：新版本头文件可能已修复与新Clang的兼容性问题，不再触发这类内部警告。

3. 按需包含头文件（可选） #

如果代码不需要OpenCL互操作功能，可以尝试只包含所需的SYCL子头文件，而非顶层的<CL/sycl.hpp>。但该方法局限性大，仅适用于极简项目。

内容的提问来源于stack exchange，提问作者Alejandro Arcila