[INFRA] Import NVIDIA/CCCL upstream as optimization reference library

CCCL (CUDA C++ Core Libraries) provides:
- CUB: device/block/warp-level GPU primitives (reduce, scan, sort, topk)
- Thrust: high-level parallel algorithms (transform_reduce, sort, scan)
- libcudacxx: CUDA C++ standard library (atomics, barriers, memory)
- cudax: experimental features (memory resources, allocators)
- Tuning policies: per-SM hardware-specific algorithm parameters

Competition optimization vectors mapped to CCCL:
- Output TPS (83% weight): warp_reduce, block_reduce, device_topk
- Input TPS (14% weight): device_scan, block_load, prefetch
- Cache TPS (3% weight): prefix caching strategy patterns
- Memory (0.9 util): pooled/cached/buddy allocators

Source: https://github.com/NVIDIA/cccl (shallow clone, HEAD only)
License: Apache-2.0

cccl_upstream/cub/cub/util_debug.cuh

@@ -0,0 +1,187 @@
+// SPDX-FileCopyrightText: Copyright (c) 2011, Duane Merrill. All rights reserved.
+// SPDX-FileCopyrightText: Copyright (c) 2011-2022, NVIDIA CORPORATION. All rights reserved.
+// SPDX-License-Identifier: BSD-3
+
+/**
+ * \file
+ * Error and event logging routines.
+ *
+ * The following macros definitions are supported:
+ * - \p CUB_LOG.  Simple event messages are printed to \p stdout.
+ */
+
+#pragma once
+
+#include <cub/config.cuh>
+
+#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 <nv/target>
+
+#ifdef _CCCL_DOXYGEN_INVOKED // Only parse this during doxygen passes:
+
+/**
+ * @def CUB_DEBUG_LOG
+ *
+ * Causes kernel launch configurations to be printed to the console
+ */
+#  define CUB_DEBUG_LOG
+
+/**
+ * @def CUB_DEBUG_SYNC
+ *
+ * Causes synchronization of the stream after every kernel launch to check
+ * for errors. Also causes kernel launch configurations to be printed to the
+ * console.
+ */
+#  define CUB_DEBUG_SYNC
+
+/**
+ * @def CUB_DEBUG_ALL
+ *
+ * Causes host and device-side precondition assertions to be checked. Apart
+ * from that, causes synchronization of the stream after every kernel launch to
+ * check for errors. Also causes kernel launch configurations to be printed to
+ * the console.
+ */
+#  define CUB_DEBUG_ALL
+
+#endif // _CCCL_DOXYGEN_INVOKED
+
+// CUB_DEBUG_SYNC also enables CUB_DEBUG_LOG
+#ifdef CUB_DEBUG_SYNC
+#  ifndef CUB_DEBUG_LOG
+#    define CUB_DEBUG_LOG
+#  endif
+#endif
+
+// CUB_DEBUG_ALL = CUB_DEBUG_LOG + CUB_DEBUG_SYNC
+#ifdef CUB_DEBUG_ALL
+#  ifndef CUB_DEBUG_LOG
+#    define CUB_DEBUG_LOG
+#  endif // CUB_DEBUG_LOG
+#  ifndef CUB_DEBUG_SYNC
+#    define CUB_DEBUG_SYNC
+#  endif // CUB_DEBUG_SYNC
+#endif // CUB_DEBUG_ALL
+
+/// CUB error reporting macro (prints error messages to stderr)
+#if (defined(DEBUG) || defined(_DEBUG)) && !defined(CUB_STDERR)
+#  define CUB_STDERR
+#endif
+
+#if defined(CUB_STDERR) || defined(CUB_DEBUG_LOG)
+#  include <cuda/std/__host_stdlib/cstdio>
+#endif
+
+CUB_NAMESPACE_BEGIN
+
+/**
+ * \brief %If \p CUB_STDERR is defined and \p error is not \p cudaSuccess, the
+ * corresponding error message is printed to \p stderr (or \p stdout in device
+ * code) along with the supplied source context.
+ *
+ * \return The CUDA error.
+ */
+_CCCL_HOST_DEVICE _CCCL_FORCEINLINE cudaError_t
+Debug(cudaError_t error, [[maybe_unused]] const char* filename, [[maybe_unused]] int line)
+{
+  // Clear the global CUDA error state which may have been set by the last
+  // call. Otherwise, errors may "leak" to unrelated kernel launches.
+
+  // clang-format off
+  #ifndef CUB_RDC_ENABLED
+  #define CUB_TEMP_DEVICE_CODE
+  #else
+  #define CUB_TEMP_DEVICE_CODE last_error = cudaGetLastError()
+  #endif
+
+  cudaError_t last_error = cudaSuccess;
+
+  NV_IF_ELSE_TARGET(
+    NV_IS_HOST,
+    (last_error = cudaGetLastError();),
+    (CUB_TEMP_DEVICE_CODE;)
+  );
+
+  #undef CUB_TEMP_DEVICE_CODE
+  // clang-format on
+
+  if (error == cudaSuccess && last_error != cudaSuccess)
+  {
+    error = last_error;
+  }
+
+#ifdef CUB_STDERR
+  if (error)
+  {
+    NV_IF_ELSE_TARGET(
+      NV_IS_HOST,
+      (fprintf(stderr, "CUDA error %d [%s, %d]: %s\n", error, filename, line, cudaGetErrorString(error));
+       fflush(stderr);),
+      (printf("CUDA error %d [block (%d,%d,%d) thread (%d,%d,%d), %s, %d]\n",
+              error,
+              blockIdx.z,
+              blockIdx.y,
+              blockIdx.x,
+              threadIdx.z,
+              threadIdx.y,
+              threadIdx.x,
+              filename,
+              line);));
+  }
+#endif
+
+  return error;
+}
+
+/**
+ * \brief Debug macro
+ */
+#ifndef CubDebug
+#  define CubDebug(e) CUB_NS_QUALIFIER::Debug((cudaError_t) (e), __FILE__, __LINE__)
+#endif
+
+/**
+ * \brief Debug macro with exit
+ */
+#ifndef CubDebugExit
+#  define CubDebugExit(e)                                               \
+    if (CUB_NS_QUALIFIER::Debug((cudaError_t) (e), __FILE__, __LINE__)) \
+    {                                                                   \
+      exit(1);                                                          \
+    }
+#endif
+
+/**
+ * \brief Log macro for printf statements.
+ */
+#if !defined(_CubLog)
+#  if _CCCL_HOSTJIT()
+#    define _CubLog(format, ...) (void(0))
+#  else // ^^^ _CCCL_HOSTJIT() ^^^ / vvv !_CCCL_HOSTJIT() vvv
+#    define _CubLog(format, ...)                                    \
+      do                                                            \
+      {                                                             \
+        NV_IF_ELSE_TARGET(                                          \
+          NV_IS_HOST,                                               \
+          (printf(format, __VA_ARGS__);),                           \
+          (printf("[block (%d,%d,%d), thread (%d,%d,%d)]: " format, \
+                  blockIdx.z,                                       \
+                  blockIdx.y,                                       \
+                  blockIdx.x,                                       \
+                  threadIdx.z,                                      \
+                  threadIdx.y,                                      \
+                  threadIdx.x,                                      \
+                  __VA_ARGS__);));                                  \
+      } while (false)
+#  endif // !_CCCL_HOSTJIT()
+#endif // !defined(_CubLog)
+
+CUB_NAMESPACE_END