cuda_toolkit/include/cub/detail/detect_cuda_runtime.cuh

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 * Copyright (c) 2011, Duane Merrill.  All rights reserved.
 * Copyright (c) 2011-2021, NVIDIA CORPORATION.  All rights reserved.
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 *       names of its contributors may be used to endorse or promote products
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/**
 * @file
 * Utilities for CUDA dynamic parallelism.
 */

#pragma once

// We cannot use `cub/config.cuh` here due to circular dependencies
#include <cuda/__cccl_config>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cuda_runtime_api.h>

#ifdef DOXYGEN_SHOULD_SKIP_THIS // Only parse this during doxygen passes:

/**
 * \def CUB_DISABLE_CDP
 *
 * If defined, support for device-side usage of CUB is disabled.
 */
#define CUB_DISABLE_CDP

/**
 * \def CUB_RDC_ENABLED
 *
 * Defined if RDC is enabled and CUB_DISABLE_CDP is not defined.
 */
#define CUB_RDC_ENABLED

/**
 * \def CUB_RUNTIME_FUNCTION
 *
 * Execution space for functions that can use the CUDA runtime API (`__host__`
 * when RDC is off, `__host__ __device__` when RDC is on).
 */
#define CUB_RUNTIME_FUNCTION

/**
 * \def CUB_RUNTIME_ENABLED
 *
 * Whether or not the active compiler pass is allowed to invoke device kernels
 * or methods from the CUDA runtime API.
 *
 * This macro should not be used in CUB, as it depends on `__CUDA_ARCH__`
 * and is not compatible with `NV_IF_TARGET`. It is provided for legacy
 * purposes only.
 *
 * Replace any usages with `CUB_RDC_ENABLED` and `NV_IF_TARGET`.
 */
#define CUB_RUNTIME_ENABLED

#else // Non-doxygen pass:

#ifndef CUB_RUNTIME_FUNCTION

#if defined(__CUDACC_RDC__) && !defined(CUB_DISABLE_CDP)

#define CUB_RDC_ENABLED
#define CUB_RUNTIME_FUNCTION __host__ __device__

#else // RDC disabled:

#define CUB_RUNTIME_FUNCTION __host__

#endif // RDC enabled

#if !defined(__CUDA_ARCH__) || defined(__CUDACC_RDC__)
// Legacy only -- do not use in new code.
#define CUB_RUNTIME_ENABLED
#endif

#endif // CUB_RUNTIME_FUNCTION predefined

#ifdef CUB_RDC_ENABLED
// Detect available version of CDP:
#if __CUDACC_VER_MAJOR__ < 12 || defined(CUDA_FORCE_CDP1_IF_SUPPORTED)
#define CUB_DETAIL_CDPv1
#else
#define CUB_DETAIL_CDPv2
#endif
#endif

#endif // Do not document