forked from rpms/glibc
209 lines
8.3 KiB
Diff
209 lines
8.3 KiB
Diff
Partial backport of:
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commit 7e1d42400c1b8f03316fe14176133c8853cd3bbe
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Author: Joseph Myers <joseph@codesourcery.com>
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Date: Fri Nov 30 15:20:41 2018 +0000
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Replace gen-as-const.awk by gen-as-const.py.
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This patch replaces gen-as-const.awk, and some fragments of the
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Makefile code that used it, by a Python script. The point is not such
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much that awk is problematic for this particular script, as that I'd
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like to build up a general Python infrastructure for extracting
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information from C headers, for use in writing tests of such headers.
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Thus, although this patch does not set up such infrastructure, the
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compute_c_consts function in gen-as-const.py might be moved to a
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separate Python module in a subsequent patch as a starting point for
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such infrastructure.
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The general idea of the code is the same as in the awk version, but no
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attempt is made to make the output files textually identical. When
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generating a header, a dict of constant names and values is generated
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internally then defines are printed in sorted order (rather than the
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order in the .sym file, which would have been used before). When
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generating a test that the values computed match those from a normal
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header inclusion, the test code is made into a compilation test using
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_Static_assert, where previously the comparisons were done only when
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the test was executed. One fragment of test generation (converting
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the previously generated header to use asconst_* prefixes on its macro
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names) is still in awk code in the makefiles; only the .sym processing
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and subsequent execution of the compiler to extract constants have
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moved to the Python script.
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Tested for x86_64, and with build-many-glibcs.py.
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* scripts/gen-as-const.py: New file.
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* scripts/gen-as-const.awk: Remove.
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* Makerules ($(common-objpfx)%.h $(common-objpfx)%.h.d): Use
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gen-as-const.py.
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($(objpfx)test-as-const-%.c): Likewise.
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In the downstream version, scripts/gen-as-const.awk is not removed and
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still used in Makerules.
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diff --git a/scripts/gen-as-const.py b/scripts/gen-as-const.py
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new file mode 100644
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index 0000000000000000..b7a5744bb192dd67
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--- /dev/null
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+++ b/scripts/gen-as-const.py
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@@ -0,0 +1,159 @@
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+#!/usr/bin/python3
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+# Produce headers of assembly constants from C expressions.
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+# Copyright (C) 2018 Free Software Foundation, Inc.
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+# This file is part of the GNU C Library.
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+#
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+# The GNU C Library is free software; you can redistribute it and/or
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+# modify it under the terms of the GNU Lesser General Public
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+# License as published by the Free Software Foundation; either
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+# version 2.1 of the License, or (at your option) any later version.
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+#
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+# The GNU C Library is distributed in the hope that it will be useful,
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+# but WITHOUT ANY WARRANTY; without even the implied warranty of
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+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+# Lesser General Public License for more details.
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+#
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+# You should have received a copy of the GNU Lesser General Public
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+# License along with the GNU C Library; if not, see
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+# <http://www.gnu.org/licenses/>.
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+
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+# The input to this script looks like:
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+# #cpp-directive ...
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+# NAME1
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+# NAME2 expression ...
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+# A line giving just a name implies an expression consisting of just that name.
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+
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+import argparse
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+import os.path
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+import re
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+import subprocess
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+import tempfile
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+
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+
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+def compute_c_consts(sym_data, cc):
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+ """Compute the values of some C constants.
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+
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+ The first argument is a list whose elements are either strings
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+ (preprocessor directives) or pairs of strings (a name and a C
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+ expression for the corresponding value). Preprocessor directives
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+ in the middle of the list may be used to select which constants
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+ end up being evaluated using which expressions.
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+
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+ """
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+ out_lines = []
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+ started = False
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+ for arg in sym_data:
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+ if isinstance(arg, str):
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+ out_lines.append(arg)
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+ continue
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+ name = arg[0]
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+ value = arg[1]
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+ if not started:
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+ out_lines.append('void\ndummy (void)\n{')
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+ started = True
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+ out_lines.append('asm ("@@@name@@@%s@@@value@@@%%0@@@end@@@" '
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+ ': : \"i\" ((long int) (%s)));'
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+ % (name, value))
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+ if started:
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+ out_lines.append('}')
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+ out_lines.append('')
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+ out_text = '\n'.join(out_lines)
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+ with tempfile.TemporaryDirectory() as temp_dir:
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+ c_file_name = os.path.join(temp_dir, 'test.c')
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+ s_file_name = os.path.join(temp_dir, 'test.s')
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+ with open(c_file_name, 'w') as c_file:
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+ c_file.write(out_text)
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+ # Compilation has to be from stdin to avoid the temporary file
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+ # name being written into the generated dependencies.
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+ cmd = ('%s -S -o %s -x c - < %s' % (cc, s_file_name, c_file_name))
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+ subprocess.check_call(cmd, shell=True)
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+ consts = {}
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+ with open(s_file_name, 'r') as s_file:
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+ for line in s_file:
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+ match = re.search('@@@name@@@([^@]*)'
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+ '@@@value@@@[^0-9Xxa-fA-F-]*'
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+ '([0-9Xxa-fA-F-]+).*@@@end@@@', line)
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+ if match:
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+ if (match.group(1) in consts
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+ and match.group(2) != consts[match.group(1)]):
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+ raise ValueError('duplicate constant %s'
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+ % match.group(1))
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+ consts[match.group(1)] = match.group(2)
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+ return consts
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+
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+
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+def gen_test(sym_data):
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+ """Generate a test for the values of some C constants.
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+
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+ The first argument is as for compute_c_consts.
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+
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+ """
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+ out_lines = []
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+ started = False
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+ for arg in sym_data:
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+ if isinstance(arg, str):
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+ out_lines.append(arg)
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+ continue
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+ name = arg[0]
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+ value = arg[1]
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+ if not started:
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+ out_lines.append('#include <stdint.h>\n'
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+ '#include <stdio.h>\n'
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+ '#include <bits/wordsize.h>\n'
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+ '#if __WORDSIZE == 64\n'
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+ 'typedef uint64_t c_t;\n'
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+ '# define U(n) UINT64_C (n)\n'
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+ '#else\n'
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+ 'typedef uint32_t c_t;\n'
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+ '# define U(n) UINT32_C (n)\n'
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+ '#endif\n'
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+ 'static int\n'
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+ 'do_test (void)\n'
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+ '{\n'
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+ # Compilation test only, using static assertions.
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+ ' return 0;\n'
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+ '}\n'
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+ '#include <support/test-driver.c>')
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+ started = True
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+ out_lines.append('_Static_assert (U (asconst_%s) == (c_t) (%s), '
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+ '"value of %s");'
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+ % (name, value, name))
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+ return '\n'.join(out_lines)
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+
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+
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+def main():
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+ """The main entry point."""
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+ parser = argparse.ArgumentParser(
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+ description='Produce headers of assembly constants.')
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+ parser.add_argument('--cc', metavar='CC',
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+ help='C compiler (including options) to use')
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+ parser.add_argument('--test', action='store_true',
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+ help='Generate test case instead of header')
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+ parser.add_argument('sym_file',
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+ help='.sym file to process')
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+ args = parser.parse_args()
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+ sym_data = []
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+ with open(args.sym_file, 'r') as sym_file:
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+ for line in sym_file:
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+ line = line.strip()
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+ if line == '':
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+ continue
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+ # Pass preprocessor directives through.
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+ if line.startswith('#'):
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+ sym_data.append(line)
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+ continue
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+ words = line.split(maxsplit=1)
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+ # Separator.
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+ if words[0] == '--':
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+ continue
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+ name = words[0]
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+ value = words[1] if len(words) > 1 else words[0]
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+ sym_data.append((name, value))
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+ if args.test:
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+ print(gen_test(sym_data))
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+ else:
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+ consts = compute_c_consts(sym_data, args.cc)
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+ print('\n'.join('#define %s %s' % c for c in sorted(consts.items())))
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+
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+if __name__ == '__main__':
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+ main()
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