1. extern void registerCPUBackendCreator();
    3. #ifdef ENABLE_ARMV82
    4. #if defined(__aarch64__) && defined(__APPLE__)
    5. extern void registerArm82BackendCreator();
    6. #endif
    7. #endif
    10. #ifdef MNN_CODEGEN_REGISTER
    11. extern void registerMetalBackendCreator();
    12. #endif
    13. void registerBackend() {
    14.     static std::once_flag s_flag;
    15.     std::call_once(s_flag, [&]() {
    16.         registerCPUBackendCreator();
    18. #ifdef ENABLE_ARMV82        
    19. #if defined(__aarch64__) && defined(__APPLE__)
    20.         registerArm82BackendCreator();
    21. #endif
    22. #endif
    24. #ifdef MNN_CODEGEN_REGISTER
    25.         registerMetalBackendCreator();
    26. #endif
    27.     });
    28. }

    根据宏定义确定注册BackendCreator的种类