1#!/usr/bin/env python
2"""Calls `gn` with the right --dotfile= and --root= arguments for LLVM."""
3
4# GN normally expects a file called '.gn' at the root of the repository.
5# Since LLVM's GN build isn't supported, putting that file at the root
6# is deemed inappropriate, which requires passing --dotfile= and -root= to GN.
7# Since that gets old fast, this script automatically passes these arguments.
8
9import os
10import subprocess
11import sys
12
13
14THIS_DIR = os.path.dirname(__file__)
15ROOT_DIR = os.path.join(THIS_DIR, '..', '..', '..')
16
17
18def get_platform():
19    import platform
20    if sys.platform == 'darwin':
21        return 'mac-amd64' if platform.machine() != 'arm64' else 'mac-arm64'
22    if platform.machine() not in ('AMD64', 'x86_64'):
23        return None
24    if sys.platform.startswith('linux'):
25        return 'linux-amd64'
26    if sys.platform == 'win32':
27        return 'windows-amd64'
28
29
30def print_no_gn(mention_get):
31    print('gn binary not found in PATH')
32    if mention_get:
33        print('run llvm/utils/gn/get.py to download a binary and try again, or')
34    print('follow https://gn.googlesource.com/gn/#getting-started')
35    return 1
36
37
38def main():
39    # Find real gn executable.
40    gn = 'gn'
41    if subprocess.call('gn --version', stdout=open(os.devnull, 'w'),
42                                       stderr=subprocess.STDOUT,
43                                       shell=True) != 0:
44        # Not on path. See if get.py downloaded a prebuilt binary and run that
45        # if it's there, or suggest to run get.py if it isn't.
46        platform = get_platform()
47        if not platform:
48            return print_no_gn(mention_get=False)
49        gn = os.path.join(os.path.dirname(__file__), 'bin', platform, 'gn')
50        if not os.path.exists(gn + ('.exe' if sys.platform == 'win32' else '')):
51            return print_no_gn(mention_get=True)
52
53    # Compute --dotfile= and --root= args to add.
54    extra_args = []
55    gn_main_arg = next((x for x in sys.argv[1:] if not x.startswith('-')), None)
56    if gn_main_arg != 'help':  # `gn help` gets confused by the switches.
57        cwd = os.getcwd()
58        dotfile = os.path.relpath(os.path.join(THIS_DIR, '.gn'), cwd)
59        root = os.path.relpath(ROOT_DIR, cwd)
60        extra_args = [ '--dotfile=' + dotfile, '--root=' + root ]
61
62    # Run GN command with --dotfile= and --root= added.
63    cmd = [gn] + extra_args + sys.argv[1:]
64    sys.exit(subprocess.call(cmd))
65
66
67if __name__ == '__main__':
68    main()
69