unused-syms

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from argparse import ArgumentParser
from collections import defaultdict
from os import path
import subprocess
import sys

__author__ = 'Michał Leśniewski'
__contact__ = 'm.lesniewski@samsung.com'
__version__ = '0.1'

def process_file(readelf, file):
    cmd = [readelf, '-s', '-W', file]

    imports, exports = set(), set()

    for line in subprocess.check_output(cmd).split('\n'):
        try:
            num, val, size, type, bind, vis, ndx, name = line.split()

            if bind != 'GLOBAL':
                continue

            num = int(num[:-1])
            val = int(val, 16)
            size = int(size)

            if ndx == 'UND':
                imports.add(name)
            else:
                exports.add(name)

        except ValueError:
            pass

    return imports, exports 


def main():
    parser = ArgumentParser(description='Find unreferenced global symbols in a set of object files.')
    parser.add_argument('--check', type=str, nargs='*', default=[], help='only print symbols from the given file')
    parser.add_argument('--ignore', type=str, nargs='*', default=['main'], help='ignore the given symbols (by default only main is ignored)')
    parser.add_argument('--readelf', type=str, nargs='?', default='readelf', help='specify readelf path')
    parser.add_argument('input', type=str, nargs='+', help='object file')

    args = parser.parse_args()

    ignore = set(args.ignore)
    exportmap = defaultdict(list)
    exported, imported = set(), set()

    # Use nicely formatted paths 
    files = [path.relpath(path.normpath(f)) for f in args.input]
    check = [path.relpath(path.normpath(f)) for f in args.check]

    if check:
        check = [x for x in check if x in files]
    else:
        check = files

    for file in files:
        try:
            i, e = process_file(args.readelf, file)
        except (subprocess.CalledProcessError, OSError), e:
            print e 
            sys.exit(-1)

        for s in e:
            exportmap[s].append(file)
        exported |= e
        imported |= i

    total = 0;
    unused = sorted(exported - imported - ignore)
    
    for file in check:
        unused_in_file = [x for x in unused if file in exportmap[x]]
        if not unused_in_file:
            continue
        total += len(unused_in_file)
        print '%s:' % file
        for symbol in unused_in_file:
            print '    %s' % symbol
        print
    print '%i unreferenced symbol%s found.' % (total, '' if total == 1 else 's')


if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        print
        print 'Aborted.'