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Diffstat (limited to 'scripts/gen-as-const.py')
| -rw-r--r-- | scripts/gen-as-const.py | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/scripts/gen-as-const.py b/scripts/gen-as-const.py new file mode 100644 index 0000000000..b7a5744bb1 --- /dev/null +++ b/scripts/gen-as-const.py @@ -0,0 +1,159 @@ +#!/usr/bin/python3 +# Produce headers of assembly constants from C expressions. +# Copyright (C) 2018 Free Software Foundation, Inc. +# This file is part of the GNU C Library. +# +# The GNU C Library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# The GNU C Library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with the GNU C Library; if not, see +# <http://www.gnu.org/licenses/>. + +# The input to this script looks like: +# #cpp-directive ... +# NAME1 +# NAME2 expression ... +# A line giving just a name implies an expression consisting of just that name. + +import argparse +import os.path +import re +import subprocess +import tempfile + + +def compute_c_consts(sym_data, cc): + """Compute the values of some C constants. + + The first argument is a list whose elements are either strings + (preprocessor directives) or pairs of strings (a name and a C + expression for the corresponding value). Preprocessor directives + in the middle of the list may be used to select which constants + end up being evaluated using which expressions. + + """ + out_lines = [] + started = False + for arg in sym_data: + if isinstance(arg, str): + out_lines.append(arg) + continue + name = arg[0] + value = arg[1] + if not started: + out_lines.append('void\ndummy (void)\n{') + started = True + out_lines.append('asm ("@@@name@@@%s@@@value@@@%%0@@@end@@@" ' + ': : \"i\" ((long int) (%s)));' + % (name, value)) + if started: + out_lines.append('}') + out_lines.append('') + out_text = '\n'.join(out_lines) + with tempfile.TemporaryDirectory() as temp_dir: + c_file_name = os.path.join(temp_dir, 'test.c') + s_file_name = os.path.join(temp_dir, 'test.s') + with open(c_file_name, 'w') as c_file: + c_file.write(out_text) + # Compilation has to be from stdin to avoid the temporary file + # name being written into the generated dependencies. + cmd = ('%s -S -o %s -x c - < %s' % (cc, s_file_name, c_file_name)) + subprocess.check_call(cmd, shell=True) + consts = {} + with open(s_file_name, 'r') as s_file: + for line in s_file: + match = re.search('@@@name@@@([^@]*)' + '@@@value@@@[^0-9Xxa-fA-F-]*' + '([0-9Xxa-fA-F-]+).*@@@end@@@', line) + if match: + if (match.group(1) in consts + and match.group(2) != consts[match.group(1)]): + raise ValueError('duplicate constant %s' + % match.group(1)) + consts[match.group(1)] = match.group(2) + return consts + + +def gen_test(sym_data): + """Generate a test for the values of some C constants. + + The first argument is as for compute_c_consts. + + """ + out_lines = [] + started = False + for arg in sym_data: + if isinstance(arg, str): + out_lines.append(arg) + continue + name = arg[0] + value = arg[1] + if not started: + out_lines.append('#include <stdint.h>\n' + '#include <stdio.h>\n' + '#include <bits/wordsize.h>\n' + '#if __WORDSIZE == 64\n' + 'typedef uint64_t c_t;\n' + '# define U(n) UINT64_C (n)\n' + '#else\n' + 'typedef uint32_t c_t;\n' + '# define U(n) UINT32_C (n)\n' + '#endif\n' + 'static int\n' + 'do_test (void)\n' + '{\n' + # Compilation test only, using static assertions. + ' return 0;\n' + '}\n' + '#include <support/test-driver.c>') + started = True + out_lines.append('_Static_assert (U (asconst_%s) == (c_t) (%s), ' + '"value of %s");' + % (name, value, name)) + return '\n'.join(out_lines) + + +def main(): + """The main entry point.""" + parser = argparse.ArgumentParser( + description='Produce headers of assembly constants.') + parser.add_argument('--cc', metavar='CC', + help='C compiler (including options) to use') + parser.add_argument('--test', action='store_true', + help='Generate test case instead of header') + parser.add_argument('sym_file', + help='.sym file to process') + args = parser.parse_args() + sym_data = [] + with open(args.sym_file, 'r') as sym_file: + for line in sym_file: + line = line.strip() + if line == '': + continue + # Pass preprocessor directives through. + if line.startswith('#'): + sym_data.append(line) + continue + words = line.split(maxsplit=1) + # Separator. + if words[0] == '--': + continue + name = words[0] + value = words[1] if len(words) > 1 else words[0] + sym_data.append((name, value)) + if args.test: + print(gen_test(sym_data)) + else: + consts = compute_c_consts(sym_data, args.cc) + print('\n'.join('#define %s %s' % c for c in sorted(consts.items()))) + +if __name__ == '__main__': + main() |