Link order test

lpt.py

#!/usr/bin/env python

import sys
import os
import subprocess

try:
	threads = int(os.environ['LPT'])
except:
	threads = 1
	
libs = []
rest = []
for arg in sys.argv[1:]:
	try:
		if arg[0:2] == '-l':
			libs.append( arg )
		else:
			rest.append( arg )
	except Exception,e:
		print(e)

import itertools
perms = [p for p in itertools.permutations(libs)]
procs = []
for i in range(len(perms)/threads + 1):
	for p in range(threads):
		if (i*threads + p) >= len(perms):
			break
		perm = perms[i*threads + p]
		call = list(rest)
		call.extend(perm)
		procs.append(subprocess.Popen(call))

	while True:
		rets = [p.poll() for p in procs]
		if not None in rets:
			idx = rets.index(0)
			if idx != -1:
				perm = perms[i*threads + idx]
				print ' '.join(rest) , ' '.join(perm)
				print 'old: ', ' '.join(libs)
				print 'new: ', ' '.join(perm)
				sys.exit(0)
			break

About: Empircal Link Order Determination
Usage: ./lpt.py g++ -omyprog my.o compiled.o code.o -L/libs -llib1 -llib2 -L/morelibs
Output: A working link command as well as a comparision of input order of -l's and working order of -l's
Extra: As this permutation approach can take quite while (dependeing on the number of libs to link) lpt checks for the environment variable LPT and starts with as many threads.
License: zlib/libpng