1#!/usr/bin/env python
2
3"""Reduces GlobalISel failures.
4
5This script is a utility to reduce tests that GlobalISel
6fails to compile.
7
8It runs llc to get the error message using a regex and creates
9a custom command to check that specific error. Then, it runs bugpoint
10with the custom command.
11
12"""
13from __future__ import print_function
14import argparse
15import re
16import subprocess
17import sys
18import tempfile
19import os
20
21
22def log(msg):
23    print(msg)
24
25
26def hr():
27    log('-' * 50)
28
29
30def log_err(msg):
31    print('ERROR: {}'.format(msg), file=sys.stderr)
32
33
34def check_path(path):
35    if not os.path.exists(path):
36        log_err('{} does not exist.'.format(path))
37        raise
38    return path
39
40
41def check_bin(build_dir, bin_name):
42    file_name = '{}/bin/{}'.format(build_dir, bin_name)
43    return check_path(file_name)
44
45
46def run_llc(llc, irfile):
47    pr = subprocess.Popen([llc,
48                           '-o',
49                           '-',
50                           '-global-isel',
51                           '-pass-remarks-missed=gisel',
52                           irfile],
53                          stdout=subprocess.PIPE,
54                          stderr=subprocess.PIPE)
55    out, err = pr.communicate()
56    res = pr.wait()
57    if res == 0:
58        return 0
59    re_err = re.compile(
60        r'LLVM ERROR: ([a-z\s]+):.*(G_INTRINSIC[_A-Z]* <intrinsic:@[a-zA-Z0-9\.]+>|G_[A-Z_]+)')
61    match = re_err.match(err)
62    if not match:
63        return 0
64    else:
65        return [match.group(1), match.group(2)]
66
67
68def run_bugpoint(bugpoint_bin, llc_bin, opt_bin, tmp, ir_file):
69    compileCmd = '-compile-command={} -c {} {}'.format(
70        os.path.realpath(__file__), llc_bin, tmp)
71    pr = subprocess.Popen([bugpoint_bin,
72                           '-compile-custom',
73                           compileCmd,
74                           '-opt-command={}'.format(opt_bin),
75                           ir_file])
76    res = pr.wait()
77    if res != 0:
78        log_err("Unable to reduce the test.")
79        raise
80
81
82def run_bugpoint_check():
83    path_to_llc = sys.argv[2]
84    path_to_err = sys.argv[3]
85    path_to_ir = sys.argv[4]
86    with open(path_to_err, 'r') as f:
87        err = f.read()
88        res = run_llc(path_to_llc, path_to_ir)
89        if res == 0:
90            return 0
91        log('GlobalISed failed, {}: {}'.format(res[0], res[1]))
92        if res != err.split(';'):
93            return 0
94        else:
95            return 1
96
97
98def main():
99    # Check if this is called by bugpoint.
100    if len(sys.argv) == 5 and sys.argv[1] == '-c':
101        sys.exit(run_bugpoint_check())
102
103    # Parse arguments.
104    parser = argparse.ArgumentParser(
105        description=__doc__, formatter_class=argparse.RawTextHelpFormatter)
106    parser.add_argument('BuildDir', help="Path to LLVM build directory")
107    parser.add_argument('IRFile', help="Path to the input IR file")
108    args = parser.parse_args()
109
110    # Check if the binaries exist.
111    build_dir = check_path(args.BuildDir)
112    ir_file = check_path(args.IRFile)
113    llc_bin = check_bin(build_dir, 'llc')
114    opt_bin = check_bin(build_dir, 'opt')
115    bugpoint_bin = check_bin(build_dir, 'bugpoint')
116
117    # Run llc to see if GlobalISel fails.
118    log('Running llc...')
119    res = run_llc(llc_bin, ir_file)
120    if res == 0:
121        log_err("Expected failure")
122        raise
123    hr()
124    log('GlobalISel failed, {}: {}.'.format(res[0], res[1]))
125    tmp = tempfile.NamedTemporaryFile()
126    log('Writing error to {} for bugpoint.'.format(tmp.name))
127    tmp.write(';'.join(res))
128    tmp.flush()
129    hr()
130
131    # Run bugpoint.
132    log('Running bugpoint...')
133    run_bugpoint(bugpoint_bin, llc_bin, opt_bin, tmp.name, ir_file)
134    hr()
135    log('Done!')
136    hr()
137    output_file = 'bugpoint-reduced-simplified.bc'
138    log('Run llvm-dis to disassemble the output:')
139    log('$ {}/bin/llvm-dis -o - {}'.format(build_dir, output_file))
140    log('Run llc to reproduce the problem:')
141    log('$ {}/bin/llc -o - -global-isel '
142        '-pass-remarks-missed=gisel {}'.format(build_dir, output_file))
143
144
145if __name__ == '__main__':
146    main()
147