如何预处理pycparser的C源代码

Question

我需要使用pycparser解析我的C和C++代码,但之前需要删除预处理程序指令和注释.

所以,你知道怎么做吗？我找到了CPP预处理器,但我不知道,如果我可以像这样使用它,没有"完整"的预处理.

我也发现了一个unifdef工具,它似乎完全符合我的要求,但仅限于预处理器条件(例如#ifdef).

我不想自己编写这个工具,因为它将用于一个非常大的项目,所以我想使用一些非常复杂的东西.

---

我的尝试:

我试图找到地方,test这个代码中调用的函数在哪里:

#include <stdio.h>

// asdfdsa
/* sadfsd
 * 
 */

void test() {
    printf("asd");
}

int main() {

    test();

    test();

    return 0;
}

我用命令预处理了这段代码gcc -E -std=c99 test.c -o testP.c然后我试着用这个Python代码找到函数调用:

#-----------------------------------------------------------------
# pycparser: func_defs.py
#
# Using pycparser for printing out all the calls of some function
# in a C file.
#
# Copyright (C) 2008-2015, Eli Bendersky
# License: BSD
#-----------------------------------------------------------------
from __future__ import print_function
import sys

# This is not required if you've installed pycparser into
# your site-packages/ with setup.py
sys.path.extend(['.', '..'])

from pycparser import c_parser, c_ast, parse_file


# A visitor with some state information (the funcname it's
# looking for)
#
class FuncCallVisitor(c_ast.NodeVisitor):
    def __init__(self, funcname):
        self.funcname = funcname

    def visit_FuncCall(self, node):
        if node.name.name == self.funcname:
            print('%s called at %s' % (self.funcname, node.name.coord))


def show_func_calls(filename, funcname):
    ast = parse_file(filename, use_cpp=True)
    v = FuncCallVisitor(funcname)
    v.visit(ast)

if __name__ == "__main__":
    if len(sys.argv) > 2:
        filename = sys.argv[1]
        func = sys.argv[2]
    else:
        filename = 'test.c'
        func = 'test'

    show_func_calls(filename, func)

但仍然,我收到此错误:

Traceback (most recent call last):
  File "func_calls.py", line 46, in <module>
    show_func_calls(filename, func)
  File "func_calls.py", line 33, in show_func_calls
    ast = parse_file(filename, use_cpp=True)
  File "/usr/local/lib/python2.7/dist-packages/pycparser/__init__.py", line 93, in parse_file
    return parser.parse(text, filename)
  File "/usr/local/lib/python2.7/dist-packages/pycparser/c_parser.py", line 146, in parse
    debug=debuglevel)
  File "/usr/local/lib/python2.7/dist-packages/pycparser/ply/yacc.py", line 265, in parse
    return self.parseopt_notrack(input,lexer,debug,tracking,tokenfunc)
  File "/usr/local/lib/python2.7/dist-packages/pycparser/ply/yacc.py", line 1047, in parseopt_notrack
    tok = self.errorfunc(errtoken)
  File "/usr/local/lib/python2.7/dist-packages/pycparser/c_parser.py", line 1691, in p_error
    column=self.clex.find_tok_column(p)))
  File "/usr/local/lib/python2.7/dist-packages/pycparser/plyparser.py", line 55, in _parse_error
    raise ParseError("%s: %s" % (coord, msg))
pycparser.plyparser.ParseError: /usr/lib/gcc/x86_64-linux-gnu/4.9/include/stdarg.h:40:27: before: __gnuc_va_list

Answer 1

pycparser文档明确说明您应该使用cpp或gcc -E准备源代码进行解析.因此,"满"预处理不是问题的cpp,这是你需要为了运行功能,pycparser在你的代码.

如果您只是删除所有预处理程序指令的代码,解析将失败,因为未声明的类型(如int32_t或size_t)和库函数缺少原型.

编辑:pycparser仅支持C99语法.如果gcc出于某种原因需要使用C++代码,请运行预处理器,如下所示:

gcc -E -std=c99

EDIT2:您似乎收到了与编译器特定符号相关的更多错误.尝试使用"假"标题提供pycparser:

gcc -E -std=c99 -I/path/to/pycparser/utils/fake_libc_include