#!/usr/bin/env python
# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================

"""Crosstool wrapper for compiling CUDA programs with nvcc on Windows.

DESCRIPTION:
  This script is the Windows version of //third_party/gpus/crosstool/crosstool_wrapper_is_not_gcc
"""

from __future__ import print_function

from argparse import ArgumentParser
import os
import subprocess
import re
import sys
import pipes

# Template values set by cuda_autoconf.
CPU_COMPILER = ('/usr/bin/gcc')
GCC_HOST_COMPILER_PATH = ('/usr/bin/gcc')

NVCC_PATH = '/usr/local/cuda-9.0/bin/nvcc'
NVCC_VERSION = '9.0'
NVCC_TEMP_DIR = "C:\\Windows\\Temp\\nvcc_inter_files_tmp_dir"
supported_cuda_compute_capabilities = [ "3.0" ]

def Log(s):
  print('gpus/crosstool: {0}'.format(s))


def GetOptionValue(argv, option):
  """Extract the list of values for option from options.

  Args:
    option: The option whose value to extract, without the leading '/'.

  Returns:
    1. A list of values, either directly following the option,
    (eg., /opt val1 val2) or values collected from multiple occurrences of
    the option (eg., /opt val1 /opt val2).
    2. The leftover options.
  """

  parser = ArgumentParser(prefix_chars='/')
  parser.add_argument('/' + option, nargs='*', action='append')
  args, leftover = parser.parse_known_args(argv)
  if args and vars(args)[option]:
    return (sum(vars(args)[option], []), leftover)
  return ([], leftover)

def _update_options(nvcc_options):
  if NVCC_VERSION in ("7.0",):
    return nvcc_options

  update_options = { "relaxed-constexpr" : "expt-relaxed-constexpr" }
  return [ update_options[opt] if opt in update_options else opt
                    for opt in nvcc_options ]

def GetNvccOptions(argv):
  """Collect the -nvcc_options values from argv.

  Args:
    argv: A list of strings, possibly the argv passed to main().

  Returns:
    1. The string that can be passed directly to nvcc.
    2. The leftover options.
  """

  parser = ArgumentParser()
  parser.add_argument('-nvcc_options', nargs='*', action='append')

  args, leftover = parser.parse_known_args(argv)

  if args.nvcc_options:
    options = _update_options(sum(args.nvcc_options, []))
    return (['--' + a for a in options], leftover)
  return ([], leftover)


def InvokeNvcc(argv, log=False):
  """Call nvcc with arguments assembled from argv.

  Args:
    argv: A list of strings, possibly the argv passed to main().
    log: True if logging is requested.

  Returns:
    The return value of calling os.system('nvcc ' + args)
  """

  src_files = [f for f in argv if
               re.search('\.cpp$|\.cc$|\.c$|\.cxx$|\.C$', f)]
  if len(src_files) == 0:
    raise Error('No source files found for cuda compilation.')

  out_file = [ f for f in argv if f.startswith('/Fo') ]
  if len(out_file) != 1:
    raise Error('Please sepecify exactly one output file for cuda compilation.')
  out = ['-o', out_file[0][len('/Fo'):]]

  nvcc_compiler_options, argv = GetNvccOptions(argv)

  opt_option, argv = GetOptionValue(argv, 'O')
  opt = ['-g', '-G']
  if (len(opt_option) > 0 and opt_option[0] != 'd'):
    opt = ['-O2']

  include_options, argv = GetOptionValue(argv, 'I')
  includes = ["-I " + include for include in include_options]

  defines, argv = GetOptionValue(argv, 'D')
  defines = ['-D' + define for define in defines]

  undefines, argv = GetOptionValue(argv, 'U')
  undefines = ['-U' + define for define in undefines]

  # The rest of the unrecongized options should be passed to host compiler
  host_compiler_options = [option for option in argv if option not in (src_files + out_file)]

  m_options = ["-m64"]

  nvccopts = ['-D_FORCE_INLINES']
  for capability in supported_cuda_compute_capabilities:
    capability = capability.replace('.', '')
    nvccopts += [r'-gencode=arch=compute_%s,"code=sm_%s,compute_%s"' % (
        capability, capability, capability)]
  nvccopts += nvcc_compiler_options
  nvccopts += undefines
  nvccopts += defines
  nvccopts += m_options
  nvccopts += ['--compiler-options="' + " ".join(host_compiler_options) + '"']
  nvccopts += ['-x', 'cu'] + opt + includes + out + ['-c'] + src_files
  # If we don't specify --keep-dir, nvcc will generate intermediate files under TEMP
  # Put them under NVCC_TEMP_DIR instead, then Bazel can ignore files under NVCC_TEMP_DIR during dependency check
  # http://docs.nvidia.com/cuda/cuda-compiler-driver-nvcc/index.html#options-for-guiding-compiler-driver
  # Different actions are sharing NVCC_TEMP_DIR, so we cannot remove it if the directory already exists.
  if os.path.isfile(NVCC_TEMP_DIR):
    os.remove(NVCC_TEMP_DIR)
  if not os.path.exists(NVCC_TEMP_DIR):
    os.makedirs(NVCC_TEMP_DIR)
  nvccopts += ['--keep', '--keep-dir', NVCC_TEMP_DIR]
  cmd = [NVCC_PATH] + nvccopts
  if log:
    Log(cmd)
  proc = subprocess.Popen(cmd,
                          stdout=sys.stdout,
                          stderr=sys.stderr,
                          env=os.environ.copy(),
                          shell=True)
  proc.wait()
  return proc.returncode

def main():
  parser = ArgumentParser()
  parser.add_argument('-x', nargs=1)
  parser.add_argument('--cuda_log', action='store_true')
  args, leftover = parser.parse_known_args(sys.argv[1:])

  if args.x and args.x[0] == 'cuda':
    if args.cuda_log: Log('-x cuda')
    leftover = [pipes.quote(s) for s in leftover]
    if args.cuda_log: Log('using nvcc')
    return InvokeNvcc(leftover, log=args.cuda_log)

  # Strip our flags before passing through to the CPU compiler for files which
  # are not -x cuda. We can't just pass 'leftover' because it also strips -x.
  # We not only want to pass -x to the CPU compiler, but also keep it in its
  # relative location in the argv list (the compiler is actually sensitive to
  # this).
  cpu_compiler_flags = [flag for flag in sys.argv[1:]
                             if not flag.startswith(('--cuda_log'))
                             and not flag.startswith(('-nvcc_options'))]

  return subprocess.call([CPU_COMPILER] + cpu_compiler_flags)

if __name__ == '__main__':
  sys.exit(main())
