xref: /llvm-project/llvm/utils/gn/gn.py (revision c49770c60f26e449379447109f7d915bd8de0384) 
1#!/usr/bin/env python3
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
21    if sys.platform == "darwin":
22        return "mac-amd64" if platform.machine() != "arm64" else "mac-arm64"
23    if platform.machine() not in ("AMD64", "x86_64"):
24        return None
25    if sys.platform.startswith("linux"):
26        return "linux-amd64"
27    if sys.platform == "win32":
28        return "windows-amd64"
29
30
31def print_no_gn(mention_get):
32    print("gn binary not found in PATH")
33    if mention_get:
34        print("run llvm/utils/gn/get.py to download a binary and try again, or")
35    print("follow https://gn.googlesource.com/gn/#getting-started")
36    return 1
37
38
39def main():
40    # Find real gn executable.
41    gn = "gn"
42    if (
43        subprocess.call(
44            "gn --version",
45            stdout=subprocess.DEVNULL,
46            stderr=subprocess.STDOUT,
47            shell=True,
48        )
49        != 0
50    ):
51        # Not on path. See if get.py downloaded a prebuilt binary and run that
52        # if it's there, or suggest to run get.py if it isn't.
53        platform = get_platform()
54        if not platform:
55            return print_no_gn(mention_get=False)
56        gn = os.path.join(os.path.dirname(__file__), "bin", platform, "gn")
57        if not os.path.exists(gn + (".exe" if sys.platform == "win32" else "")):
58            return print_no_gn(mention_get=True)
59
60    # Compute --dotfile= and --root= args to add.
61    extra_args = []
62    gn_main_arg = next((x for x in sys.argv[1:] if not x.startswith("-")), None)
63    if gn_main_arg != "help":  # `gn help` gets confused by the switches.
64        cwd = os.getcwd()
65        dotfile = os.path.relpath(os.path.join(THIS_DIR, ".gn"), cwd)
66        root = os.path.relpath(ROOT_DIR, cwd)
67        extra_args = ["--dotfile=" + dotfile, "--root=" + root]
68
69    # Run GN command with --dotfile= and --root= added.
70    cmd = [gn] + extra_args + sys.argv[1:]
71    sys.exit(subprocess.call(cmd))
72
73
74if __name__ == "__main__":
75    main()
76