1#!/usr/bin/env python 2# 3# The way you use this is you create a script that takes in as its first 4# argument a count. The script passes into LLVM the count via a command 5# line flag that disables a pass after LLVM has run after the pass has 6# run for count number of times. Then the script invokes a test of some 7# sort and indicates whether LLVM successfully compiled the test via the 8# scripts exit status. Then you invoke bisect as follows: 9# 10# bisect --start=<start_num> --end=<end_num> ./script.sh "%(count)s" 11# 12# And bisect will continually call ./script.sh with various counts using 13# the exit status to determine success and failure. 14# 15from __future__ import print_function 16import os 17import sys 18import argparse 19import subprocess 20 21parser = argparse.ArgumentParser() 22 23parser.add_argument('--start', type=int, default=0) 24parser.add_argument('--end', type=int, default=(1 << 32)) 25parser.add_argument('command', nargs='+') 26 27args = parser.parse_args() 28 29start = args.start 30end = args.end 31 32print("Bisect Starting!") 33print("Start: %d" % start) 34print("End: %d" % end) 35 36last = None 37while start != end and start != end-1: 38 count = start + (end - start)//2 39 print("Visiting Count: %d with (Start, End) = (%d,%d)" % (count, start, end)) 40 cmd = [x % {'count':count} for x in args.command] 41 print(cmd) 42 result = subprocess.call(cmd) 43 if result == 0: 44 print(" PASSES! Setting start to count") 45 start = count 46 else: 47 print(" FAILS! Setting end to count") 48 end = count 49 50print("Last good count: %d" % start) 51