1#!/usr/bin/env python
2#===----------------------------------------------------------------------===##
3#
4#                     The LLVM Compiler Infrastructure
5#
6# This file is dual licensed under the MIT and the University of Illinois Open
7# Source Licenses. See LICENSE.TXT for details.
8#
9#===----------------------------------------------------------------------===##
10
11import os
12import sys
13
14def print_and_exit(msg):
15    sys.stderr.write(msg + '\n')
16    sys.exit(1)
17
18def usage_and_exit():
19    print_and_exit("Usage: ./gen_link_script.py [--help] [--dryrun] <path/to/libcxx.so> <public_libs>...")
20
21def help_and_exit():
22    help_msg = \
23"""Usage
24
25  gen_link_script.py [--help] [--dryrun] <path/to/libcxx.so> <public_libs>...
26
27  Generate a linker script that links libc++ to the proper ABI library.
28  The script replaces the specified libc++ symlink.
29  An example script for c++abi would look like "INPUT(libc++.so.1 -lc++abi)".
30
31Arguments
32  <path/to/libcxx.so> - The top level symlink to the versioned libc++ shared
33                        library. This file is replaced with a linker script.
34  <public_libs>       - List of library names to include in linker script.
35
36Exit Status:
37  0 if OK,
38  1 if the action failed.
39"""
40    print_and_exit(help_msg)
41
42def parse_args():
43    args = list(sys.argv)
44    del args[0]
45    if len(args) == 0:
46        usage_and_exit()
47    if args[0] == '--help':
48        help_and_exit()
49    dryrun = '--dryrun' == args[0]
50    if dryrun:
51        del args[0]
52    if len(args) < 2:
53        usage_and_exit()
54    symlink_file = args[0]
55    public_libs = args[1:]
56    return dryrun, symlink_file, public_libs
57
58def main():
59    dryrun, symlink_file, public_libs = parse_args()
60
61    # Check that the given libc++.so file is a valid symlink.
62    if not os.path.islink(symlink_file):
63        print_and_exit("symlink file %s is not a symlink" % symlink_file)
64
65    # Read the symlink so we know what libc++ to link to in the linker script.
66    linked_libcxx = os.readlink(symlink_file)
67
68    # Prepare the list of public libraries to link.
69    public_libs = ['-l%s' % l for l in public_libs]
70
71    # Generate the linker script contents and print the script and destination
72    # information.
73    contents = "INPUT(%s %s)" % (linked_libcxx, ' '.join(public_libs))
74    print("GENERATING SCRIPT: '%s' as file %s" % (contents, symlink_file))
75
76    # Remove the existing libc++ symlink and replace it with the script.
77    if not dryrun:
78        os.unlink(symlink_file)
79        with open(symlink_file, 'w') as f:
80            f.write(contents + "\n")
81
82
83if __name__ == '__main__':
84    main()
85