llvm-project/llvm/utils/gn/build/write_cmake_config.py

104 lines
3.2 KiB
Python
Executable File

#!/usr/bin/env python
"""Emulates the bits of CMake's configure_file() function needed in LLVM.
The CMake build uses configure_file() for several things. This emulates that
function for the GN build. In the GN build, this runs at build time, instead
of at generator time.
Takes a list of KEY=VALUE pairs (where VALUE can be empty).
On each line, replaces ${KEY} with VALUE.
After that, also handles these special cases (note that FOO= sets the value of
FOO to the empty string, which is falsy, but FOO=0 sets it to '0' which is
truthy):
1.) #cmakedefine01 FOO
Checks if key FOO is set to a truthy value, and depending on that prints
one of the following two lines:
#define FOO 1
#define FOO 0
2.) #cmakedefine FOO [...]
Checks if key FOO is set to a truthy in value, and depending on that prints
one of the following two lines:
#define FOO [...]
/* #undef FOO */
Fails if any of the KEY=VALUE arguments aren't needed for processing the
.h.cmake file, or if the .h.cmake file has unreplaced ${VAR} references after
processing all values.
"""
from __future__ import print_function
import argparse
import os
import re
import sys
def main():
parser = argparse.ArgumentParser(
epilog=__doc__,
formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('input', help='input file')
parser.add_argument('values', nargs='*', help='several KEY=VALUE pairs')
parser.add_argument('-o', '--output', required=True,
help='output file')
args = parser.parse_args()
values = {}
for value in args.values:
key, val = value.split('=', 1)
values[key] = val
unused_values = set(values.keys())
# Matches e.g. '${CLANG_FOO}' and captures CLANG_FOO in group 1.
var_re = re.compile(r'\$\{([^}]*)\}')
in_lines = open(args.input).readlines()
out_lines = []
for in_line in in_lines:
def repl(m):
unused_values.discard(m.group(1))
return values[m.group(1)]
in_line = var_re.sub(repl, in_line)
if in_line.startswith('#cmakedefine01 '):
_, var = in_line.split()
in_line = '#define %s %d\n' % (var, 1 if values[var] else 0)
unused_values.discard(var)
elif in_line.startswith('#cmakedefine '):
_, var = in_line.split(None, 1)
try:
var, val = var.split(None, 1)
in_line = '#define %s %s' % (var, val) # val ends in \n.
except:
var = var.rstrip()
in_line = '#define %s\n' % var
if not values[var]:
in_line = '/* #undef %s */\n' % var
unused_values.discard(var)
out_lines.append(in_line)
if unused_values:
print('unused values args:', file=sys.stderr)
print(' ', '\n '.join(unused_values), file=sys.stderr)
return 1
output = ''.join(out_lines)
leftovers = var_re.findall(output)
if leftovers:
print('unprocessed values:\n', '\n'.join(leftovers), file=sys.stderr)
return 1
if not os.path.exists(args.output) or open(args.output).read() != output:
open(args.output, 'w').write(output)
if __name__ == '__main__':
sys.exit(main())