scripts/construct_uffd_gc_flag.py

#!/usr/bin/env python
#
# Copyright (C) 2024 The Android Open Source Project
#
# 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.
#
"""A tool for constructing UFFD GC flag."""

import argparse
import os

from uffd_gc_utils import should_enable_uffd_gc


def parse_args():
  parser = argparse.ArgumentParser()
  parser.add_argument('kernel_version_file')
  parser.add_argument('output')
  return parser.parse_args()

def main():
  args = parse_args()
  enable_uffd_gc = should_enable_uffd_gc(args.kernel_version_file)
  flag = '--runtime-arg -Xgc:CMC' if enable_uffd_gc else ''
  # Prevent the file's mtime from being changed if the contents don't change.
  # This avoids unnecessary dexpreopt reruns.
  if os.path.isfile(args.output):
    with open(args.output, 'r') as f:
      if f.read() == flag:
        return
  with open(args.output, 'w') as f:
    f.write(flag)


if __name__ == '__main__':
  main()