1#!/usr/bin/env python 2"""A ladder graph creation program. 3 4This is a python program that creates c source code that will generate 5CFGs that are ladder graphs. Ladder graphs are generally the worst case 6for a lot of dominance related algorithms (Dominance frontiers, etc), 7and often generate N^2 or worse behavior. 8 9One good use of this program is to test whether your linear time algorithm is 10really behaving linearly. 11""" 12 13from __future__ import print_function 14 15import argparse 16 17 18def main(): 19 parser = argparse.ArgumentParser(description=__doc__) 20 parser.add_argument( 21 "rungs", type=int, help="Number of ladder rungs. Must be a multiple of 2" 22 ) 23 args = parser.parse_args() 24 if (args.rungs % 2) != 0: 25 print("Rungs must be a multiple of 2") 26 return 27 print("int ladder(int *foo, int *bar, int x) {") 28 rung1 = range(0, args.rungs, 2) 29 rung2 = range(1, args.rungs, 2) 30 for i in rung1: 31 print("rung1%d:" % i) 32 print("*foo = x++;") 33 if i != rung1[-1]: 34 print("if (*bar) goto rung1%d;" % (i + 2)) 35 print("else goto rung2%d;" % (i + 1)) 36 else: 37 print("goto rung2%d;" % (i + 1)) 38 for i in rung2: 39 print("rung2%d:" % i) 40 print("*foo = x++;") 41 if i != rung2[-1]: 42 print("goto rung2%d;" % (i + 2)) 43 else: 44 print("return *foo;") 45 print("}") 46 47 48if __name__ == "__main__": 49 main() 50