xref: /openbsd/gnu/llvm/llvm/utils/bisect-skip-count (revision f6aab3d8) 
1#!/usr/bin/env python
2# This script is used to bisect skip and count arguments for --debug-counter.
3# It is similar to bisect, except it understands how to increase skip and decrease count
4#
5# Typical usage:
6#
7# bisect-skip-count bisect-command.sh "%(skip)d" "%(count)d" 2>&1 | tee bisect.out
8#
9# bisect-command.sh is something like this:
10# #! /bin/bash
11#
12# skip=$1
13# count=$2
14#
15# opt -debug-counter=my-counter-skip=${skip},my-counter-count=${count}
16# ... Test output of opt and exit zero for pass, non-zero for fail
17#
18# Examine bisect.out to look for "Last good skip" and "Last good
19# count" to find the values of the counter that produce a passing
20# result.  Incrementing the last good count by one or decrementing the
21# last good skip by one should produce a failure.
22#
23from __future__ import print_function
24import os
25import sys
26import argparse
27# This is for timeout support. Use the recommended way of import.
28# We do timeouts because when doing, execution testing, we have a habit
29# of finding variants that infinite loop
30if os.name == 'posix' and sys.version_info[0] < 3:
31  import subprocess32 as subprocess
32else:
33  import subprocess
34parser = argparse.ArgumentParser()
35
36parser.add_argument('--skipstart', type=int, default=0)
37parser.add_argument('--skipend', type=int, default=(1 << 32))
38parser.add_argument('--countstart', type=int, default=0)
39parser.add_argument('--countend', type=int, default=(1 << 32))
40parser.add_argument('--timeout', type=int, default=None)
41# Use shell support if you need to use complex shell expressions in your command
42parser.add_argument('--shell', type=bool, default=False)
43parser.add_argument('command', nargs='+')
44
45args = parser.parse_args()
46
47start = args.skipstart
48end = args.skipend
49
50print("Bisect of Skip starting!")
51print("Start: %d" % start)
52print("End: %d" % end)
53
54last = None
55while start != end and start != end-1:
56    count = start + (end - start)//2
57    print("Visiting Skip: %d with (Start, End) = (%d,%d)" % (count, start, end))
58    cmd = [x % {'skip':count, 'count':-1} for x in args.command]
59    print(cmd)
60    try:
61        result = subprocess.call(cmd, shell=args.shell, timeout=args.timeout)
62        if result == 0:
63           print("    PASSES! Setting end to count")
64           end = count
65        else:
66           print("    FAILS! Setting start to count")
67           start = count
68    except:
69        print(" TIMEOUT, setting end to count")
70        end = count
71firstcount = start
72print("Last good skip: %d" % start)
73start = args.countstart
74end = args.countend
75print("Bisect of Count starting!")
76print("Start: %d" % start)
77print("End: %d" % end)
78while start != end and start != end-1:
79    count = start + (end - start)//2
80    print("Visiting Count: %d with (Start, End) = (%d,%d)" % (count, start, end))
81    cmd = [x % {'count':count, 'skip':firstcount } for x in args.command]
82    print(cmd)
83    try:
84        result = subprocess.call(cmd, shell=args.shell, timeout=args.timeout)
85        if result == 0:
86           print("    PASSES! Setting start to count")
87           start = count
88        else:
89           print("    FAILS! Setting end to count")
90           end = count
91    except:
92        print(" TIMEOUT, setting start to count")
93        start = count
94
95print("Last good count: %d" % start)
96