// Copyright (c) 2017-2022, Lawrence Livermore National Security, LLC and other CEED contributors.
// All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
//
// SPDX-License-Identifier: BSD-2-Clause
//
// This file is part of CEED:  http://github.com/ceed

#include "ceed-cuda-compile.h"

#include <ceed.h>
#include <ceed/backend.h>
#include <ceed/jit-tools.h>
#include <cuda_runtime.h>
#include <nvrtc.h>
#include <stdarg.h>
#include <string.h>

#include <sstream>

#include "ceed-cuda-common.h"

#define CeedChk_Nvrtc(ceed, x)                                                                              \
  do {                                                                                                      \
    nvrtcResult result = static_cast<nvrtcResult>(x);                                                       \
    if (result != NVRTC_SUCCESS) return CeedError((ceed), CEED_ERROR_BACKEND, nvrtcGetErrorString(result)); \
  } while (0)

#define CeedCallNvrtc(ceed, ...)  \
  do {                            \
    int ierr_q_ = __VA_ARGS__;    \
    CeedChk_Nvrtc(ceed, ierr_q_); \
  } while (0)

//------------------------------------------------------------------------------
// Compile CUDA kernel
//------------------------------------------------------------------------------
int CeedCompile_Cuda(Ceed ceed, const char *source, CUmodule *module, const CeedInt num_defines, ...) {
  size_t                ptx_size;
  char                 *jit_defs_path, *jit_defs_source, *ptx;
  const int             num_opts = 3;
  const char           *opts[num_opts];
  nvrtcProgram          prog;
  struct cudaDeviceProp prop;
  Ceed_Cuda            *ceed_data;

  cudaFree(0);  // Make sure a Context exists for nvrtc

  std::ostringstream code;

  // Get kernel specific options, such as kernel constants
  if (num_defines > 0) {
    va_list args;
    va_start(args, num_defines);
    char *name;
    int   val;

    for (int i = 0; i < num_defines; i++) {
      name = va_arg(args, char *);
      val  = va_arg(args, int);
      code << "#define " << name << " " << val << "\n";
    }
    va_end(args);
  }

  // Standard libCEED definitions for CUDA backends
  CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-jit.h", &jit_defs_path));
  CeedCallBackend(CeedLoadSourceToBuffer(ceed, jit_defs_path, &jit_defs_source));
  code << jit_defs_source;
  code << "\n\n";
  CeedCallBackend(CeedFree(&jit_defs_path));
  CeedCallBackend(CeedFree(&jit_defs_source));

  // Non-macro options
  opts[0] = "-default-device";
  CeedCallBackend(CeedGetData(ceed, &ceed_data));
  CeedCallCuda(ceed, cudaGetDeviceProperties(&prop, ceed_data->device_id));
  std::string arch_arg = "-arch=compute_" + std::to_string(prop.major) + std::to_string(prop.minor);
  opts[1]              = arch_arg.c_str();
  opts[2]              = "-Dint32_t=int";

  // Add string source argument provided in call
  code << source;

  // Create Program
  CeedCallNvrtc(ceed, nvrtcCreateProgram(&prog, code.str().c_str(), NULL, 0, NULL, NULL));

  // Compile kernel
  nvrtcResult result = nvrtcCompileProgram(prog, num_opts, opts);

  if (result != NVRTC_SUCCESS) {
    char  *log;
    size_t log_size;

    CeedCallNvrtc(ceed, nvrtcGetProgramLogSize(prog, &log_size));
    CeedCallBackend(CeedMalloc(log_size, &log));
    CeedCallNvrtc(ceed, nvrtcGetProgramLog(prog, log));
    return CeedError(ceed, CEED_ERROR_BACKEND, "%s\n%s", nvrtcGetErrorString(result), log);
  }

  CeedCallNvrtc(ceed, nvrtcGetPTXSize(prog, &ptx_size));
  CeedCallBackend(CeedMalloc(ptx_size, &ptx));
  CeedCallNvrtc(ceed, nvrtcGetPTX(prog, ptx));
  CeedCallNvrtc(ceed, nvrtcDestroyProgram(&prog));

  CeedCallCuda(ceed, cuModuleLoadData(module, ptx));
  CeedCallBackend(CeedFree(&ptx));
  return CEED_ERROR_SUCCESS;
}

//------------------------------------------------------------------------------
// Get CUDA kernel
//------------------------------------------------------------------------------
int CeedGetKernel_Cuda(Ceed ceed, CUmodule module, const char *name, CUfunction *kernel) {
  CeedCallCuda(ceed, cuModuleGetFunction(kernel, module, name));
  return CEED_ERROR_SUCCESS;
}

//------------------------------------------------------------------------------
// Run CUDA kernel with block size selected automatically based on the kernel
//     (which may use enough registers to require a smaller block size than the
//      hardware is capable)
//------------------------------------------------------------------------------
int CeedRunKernelAutoblockCuda(Ceed ceed, CUfunction kernel, size_t points, void **args) {
  int min_grid_size, max_block_size;

  CeedCallCuda(ceed, cuOccupancyMaxPotentialBlockSize(&min_grid_size, &max_block_size, kernel, NULL, 0, 0x10000));
  CeedCallBackend(CeedRunKernel_Cuda(ceed, kernel, CeedDivUpInt(points, max_block_size), max_block_size, args));
  return CEED_ERROR_SUCCESS;
}

//------------------------------------------------------------------------------
// Run CUDA kernel
//------------------------------------------------------------------------------
int CeedRunKernel_Cuda(Ceed ceed, CUfunction kernel, const int grid_size, const int block_size, void **args) {
  CeedCallBackend(CeedRunKernelDimShared_Cuda(ceed, kernel, grid_size, block_size, 1, 1, 0, args));
  return CEED_ERROR_SUCCESS;
}

//------------------------------------------------------------------------------
// Run CUDA kernel for spatial dimension
//------------------------------------------------------------------------------
int CeedRunKernelDim_Cuda(Ceed ceed, CUfunction kernel, const int grid_size, const int block_size_x, const int block_size_y, const int block_size_z,
                          void **args) {
  CeedCallBackend(CeedRunKernelDimShared_Cuda(ceed, kernel, grid_size, block_size_x, block_size_y, block_size_z, 0, args));
  return CEED_ERROR_SUCCESS;
}

//------------------------------------------------------------------------------
// Run CUDA kernel for spatial dimension with shared memory
//------------------------------------------------------------------------------
int CeedRunKernelDimShared_Cuda(Ceed ceed, CUfunction kernel, const int grid_size, const int block_size_x, const int block_size_y,
                                const int block_size_z, const int shared_mem_size, void **args) {
#if CUDA_VERSION >= 9000
  cuFuncSetAttribute(kernel, CU_FUNC_ATTRIBUTE_MAX_DYNAMIC_SHARED_SIZE_BYTES, shared_mem_size);
#endif
  CUresult result = cuLaunchKernel(kernel, grid_size, 1, 1, block_size_x, block_size_y, block_size_z, shared_mem_size, NULL, args, NULL);

  if (result == CUDA_ERROR_LAUNCH_OUT_OF_RESOURCES) {
    int max_threads_per_block, shared_size_bytes, num_regs;

    cuFuncGetAttribute(&max_threads_per_block, CU_FUNC_ATTRIBUTE_MAX_THREADS_PER_BLOCK, kernel);
    cuFuncGetAttribute(&shared_size_bytes, CU_FUNC_ATTRIBUTE_SHARED_SIZE_BYTES, kernel);
    cuFuncGetAttribute(&num_regs, CU_FUNC_ATTRIBUTE_NUM_REGS, kernel);
    return CeedError(ceed, CEED_ERROR_BACKEND,
                     "CUDA_ERROR_LAUNCH_OUT_OF_RESOURCES: max_threads_per_block %d on block size (%d,%d,%d), shared_size %d, num_regs %d",
                     max_threads_per_block, block_size_x, block_size_y, block_size_z, shared_size_bytes, num_regs);
  } else CeedChk_Cu(ceed, result);
  return CEED_ERROR_SUCCESS;
}

//------------------------------------------------------------------------------