1#!/usr/bin/python3
2# Produce headers of assembly constants from C expressions.
3# Copyright (C) 2018-2022 Free Software Foundation, Inc.
4# This file is part of the GNU C Library.
5#
6# The GNU C Library is free software; you can redistribute it and/or
7# modify it under the terms of the GNU Lesser General Public
8# License as published by the Free Software Foundation; either
9# version 2.1 of the License, or (at your option) any later version.
10#
11# The GNU C Library is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14# Lesser General Public License for more details.
15#
16# You should have received a copy of the GNU Lesser General Public
17# License along with the GNU C Library; if not, see
18# <https://www.gnu.org/licenses/>.
19
20# The input to this script looks like:
21#       #cpp-directive ...
22#       NAME1
23#       NAME2 expression ...
24# A line giving just a name implies an expression consisting of just that name.
25
26import argparse
27
28import glibcextract
29
30
31def gen_test(sym_data):
32    """Generate a test for the values of some C constants.
33
34    The first argument is as for glibcextract.compute_c_consts.
35
36    """
37    out_lines = []
38    for arg in sym_data:
39        if isinstance(arg, str):
40            if arg == 'START':
41                out_lines.append('#include <stdint.h>\n'
42                                 '#include <stdio.h>\n'
43                                 '#include <bits/wordsize.h>\n'
44                                 '#if __WORDSIZE == 64\n'
45                                 'typedef uint64_t c_t;\n'
46                                 '# define U(n) UINT64_C (n)\n'
47                                 '#else\n'
48                                 'typedef uint32_t c_t;\n'
49                                 '# define U(n) UINT32_C (n)\n'
50                                 '#endif\n'
51                                 'static int\n'
52                                 'do_test (void)\n'
53                                 '{\n'
54                                 # Compilation test only, using static
55                                 # assertions.
56                                 '  return 0;\n'
57                                 '}\n'
58                                 '#include <support/test-driver.c>')
59            else:
60                out_lines.append(arg)
61            continue
62        name = arg[0]
63        value = arg[1]
64        out_lines.append('_Static_assert (U (asconst_%s) == (c_t) (%s), '
65                         '"value of %s");'
66                         % (name, value, name))
67    return '\n'.join(out_lines)
68
69
70def main():
71    """The main entry point."""
72    parser = argparse.ArgumentParser(
73        description='Produce headers of assembly constants.')
74    parser.add_argument('--cc', metavar='CC',
75                        help='C compiler (including options) to use')
76    parser.add_argument('--test', action='store_true',
77                        help='Generate test case instead of header')
78    parser.add_argument('--python', action='store_true',
79                        help='Generate Python file instead of header')
80    parser.add_argument('sym_file',
81                        help='.sym file to process')
82    args = parser.parse_args()
83    sym_data = []
84    with open(args.sym_file, 'r') as sym_file:
85        started = False
86        for line in sym_file:
87            line = line.strip()
88            if line == '':
89                continue
90            # Pass preprocessor directives through.
91            if line.startswith('#'):
92                sym_data.append(line)
93                continue
94            words = line.split(maxsplit=1)
95            if not started:
96                sym_data.append('START')
97                started = True
98            # Separator.
99            if words[0] == '--':
100                continue
101            name = words[0]
102            value = words[1] if len(words) > 1 else words[0]
103            sym_data.append((name, value))
104        if not started:
105            sym_data.append('START')
106    if args.test:
107        print(gen_test(sym_data))
108    elif args.python:
109        consts = glibcextract.compute_c_consts(sym_data, args.cc)
110        print('# GENERATED FILE\n'
111              '\n'
112              '# Constant definitions.\n'
113              '# See gen-as-const.py for details.\n')
114        print(''.join('%s = %s\n' % c for c in sorted(consts.items())), end='')
115    else:
116        consts = glibcextract.compute_c_consts(sym_data, args.cc)
117        print(''.join('#define %s %s\n' % c for c in sorted(consts.items())), end='')
118
119if __name__ == '__main__':
120    main()
121