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#!/usr/bin/env python3
# libmisc/wrap-cc - Wrapper around GCC to enhance the preprocessor
#
# Copyright (C) 2025 Luke T. Shumaker <lukeshu@lukeshu.com>
# SPDX-License-Identifier: AGPL-3.0-or-later
import os
import subprocess
import sys
import typing
def scan_tuple(
text: str, beg: int, on_part: typing.Callable[[str], None] | None = None
) -> int:
assert text[beg] == "("
pos = beg + 1
arg_start = pos
parens = 1
instring = False
while parens:
c = text[pos]
if instring:
match c:
case "\\":
pos += 1
case '"':
instring = False
else:
match c:
case "(":
parens += 1
case ")":
parens -= 1
if on_part and parens == 0 and text[beg + 1 : pos].strip():
on_part(text[arg_start:pos])
case ",":
if on_part and parens == 1:
on_part(text[arg_start:pos])
arg_start = pos + 1
case '"':
instring = True
pos += 1
assert text[pos - 1] == ")"
return pos - 1
def unquote(cstr: str) -> str:
assert len(cstr) >= 2 and cstr[0] == '"' and cstr[-1] == '"'
cstr = cstr[1:-1]
out = ""
while cstr:
if cstr[0] == "\\":
match cstr[1]:
case "n":
out += "\n"
cstr = cstr[2:]
case "\\":
out += "\\"
cstr = cstr[2:]
case '"':
out += '"'
cstr = cstr[2:]
else:
out += cstr[0]
cstr = cstr[1:]
return out
def preprocess(all_args: list[str]) -> typing.NoReturn:
# argparse #################################################################
_args = all_args
def shift(n: int) -> list[str]:
nonlocal _args
ret = _args[:n]
_args = _args[n:]
return ret
arg0 = shift(1)[0]
common_flags: list[str] = []
output_flags: list[str] = []
positional: list[str] = []
while _args:
if len(_args[0]) > 2 and _args[0][0] == "-" and _args[0][1] in "IDU":
_args = [_args[0][:2], _args[0][2:], *_args[1:]]
match _args[0]:
# Mode
case "-E" | "-quiet":
common_flags += shift(1)
case "-lang-asm":
os.execvp(all_args[0], all_args)
# Search path
case "-I" | "-imultilib" | "-isystem":
common_flags += shift(2)
# Define/Undefine
case "-D" | "-U":
common_flags += shift(2)
# Optimization
case "-O0" | "-O1" | "-O2" | "-O3" | "-Os" | "-Ofast" | "-Og" | "-Oz":
common_flags += shift(1)
case "-g":
common_flags += shift(1)
# Output files
case "-MD" | "-MF" | "-MT" | "-dumpbase" | "-dumpbase-ext":
output_flags += shift(2)
case "-o":
output_flags += shift(2)
# Other
case _:
if _args[0].startswith("-"):
if _args[0].startswith("-std="):
common_flags += shift(1)
elif _args[0].startswith("-m"):
common_flags += shift(1)
elif _args[0].startswith("-f"):
common_flags += shift(1)
elif _args[0].startswith("-W"):
common_flags += shift(1)
else:
raise ValueError(f"unknown flag: {_args!r}")
else:
positional += shift(1)
if len(positional) != 1:
raise ValueError("expected 1 input file")
infile = positional[0]
# enhance ##################################################################
common_flags += ["-D", "__LIBMISC_ENHANCED_CPP__"]
text = subprocess.run(
[arg0, *common_flags, infile],
stdin=subprocess.DEVNULL,
stdout=subprocess.PIPE,
stderr=sys.stderr,
check=True,
text=True,
).stdout
macros: dict[str, str] = {}
marker = "__xx__LM_DEFAPPEND__xx__"
pos = 0
while (marker_beg := text.find(marker, pos)) >= 0:
args: list[str] = []
def add_arg(arg: str) -> None:
nonlocal args
args.append(arg)
beg_paren = marker_beg + len(marker)
end_paren = scan_tuple(text, beg_paren, add_arg)
before = text[:marker_beg]
# old = text[marker_beg : end_paren + 1]
after = text[end_paren + 1 :]
assert len(args) == 2
k = unquote(args[0].strip())
v = unquote(args[1].strip())
if k not in macros:
macros[k] = v
else:
macros[k] += " " + v
text = before + after
pos = len(before)
common_flags += ["-D", marker + "=LM_EAT"]
for k, v in macros.items():
common_flags += ["-D", k + "=" + v]
# Run, for-real ############################################################
os.execvp(arg0, [arg0, *common_flags, *output_flags, infile])
def main(all_args: list[str]) -> typing.NoReturn:
if len(all_args) >= 2 and all_args[0].endswith("cc1") and all_args[1] == "-E":
preprocess(all_args)
else:
os.execvp(all_args[0], all_args)
if __name__ == "__main__":
main(sys.argv[1:])
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