1#!/usr/bin/env python
2#
3# Copyright (C) 2024 The Android Open Source Project
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#      http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16#
17"""A tool for constructing UFFD GC flag."""
18
19import argparse
20import os
21
22from uffd_gc_utils import should_enable_uffd_gc
23
24
25def parse_args():
26  parser = argparse.ArgumentParser()
27  parser.add_argument('kernel_version_file')
28  parser.add_argument('output')
29  return parser.parse_args()
30
31def main():
32  args = parse_args()
33  enable_uffd_gc = should_enable_uffd_gc(args.kernel_version_file)
34  flag = '--runtime-arg -Xgc:CMC' if enable_uffd_gc else ''
35  # Prevent the file's mtime from being changed if the contents don't change.
36  # This avoids unnecessary dexpreopt reruns.
37  if os.path.isfile(args.output):
38    with open(args.output, 'r') as f:
39      if f.read() == flag:
40        return
41  with open(args.output, 'w') as f:
42    f.write(flag)
43
44
45if __name__ == '__main__':
46  main()
47