bugpoint_gisel_reducer.py

#!/usr/bin/env python

"""Reduces GlobalISel failures.

This script is a utility to reduce tests that GlobalISel
fails to compile.

It runs llc to get the error message using a regex and creates
a custom command to check that specific error. Then, it runs bugpoint
with the custom command.

"""
from __future__ importprint_function
importargparse
importre
importsubprocess
importsys
importtempfile
importos


deflog(msg):
print(msg)


defhr():
log('-'*50)


deflog_err(msg):
print('ERROR: {}'.format(msg), file=sys.stderr)


defcheck_path(path):
ifnotos.path.exists(path):
log_err('{} does not exist.'.format(path))
raise
returnpath


defcheck_bin(build_dir, bin_name):
file_name='{}/bin/{}'.format(build_dir, bin_name)
returncheck_path(file_name)


defrun_llc(llc, irfile):
pr=subprocess.Popen([llc,
'-o',
'-',
'-global-isel',
'-pass-remarks-missed=gisel',
irfile],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
out, err=pr.communicate()
res=pr.wait()
ifres==0:
return0
re_err=re.compile(
r'LLVM ERROR: ([a-z\s]+):.*(G_INTRINSIC[_A-Z]* <intrinsic:@[a-zA-Z0-9\.]+>|G_[A-Z_]+)')
match=re_err.match(err)
ifnotmatch:
return0
else:
return [match.group(1), match.group(2)]


defrun_bugpoint(bugpoint_bin, llc_bin, opt_bin, tmp, ir_file):
compileCmd='-compile-command={} -c {} {}'.format(
os.path.realpath(__file__), llc_bin, tmp)
pr=subprocess.Popen([bugpoint_bin,
'-compile-custom',
compileCmd,
'-opt-command={}'.format(opt_bin),
ir_file])
res=pr.wait()
ifres!=0:
log_err("Unable to reduce the test.")
raise


defrun_bugpoint_check():
path_to_llc=sys.argv[2]
path_to_err=sys.argv[3]
path_to_ir=sys.argv[4]
withopen(path_to_err, 'r') asf:
err=f.read()
res=run_llc(path_to_llc, path_to_ir)
ifres==0:
return0
log('GlobalISed failed, {}: {}'.format(res[0], res[1]))
ifres!=err.split(';'):
return0
else:
return1


defmain():
# Check if this is called by bugpoint.
iflen(sys.argv) ==5andsys.argv[1] =='-c':
sys.exit(run_bugpoint_check())

# Parse arguments.
parser=argparse.ArgumentParser(
description=__doc__, formatter_class=argparse.RawTextHelpFormatter)
parser.add_argument('BuildDir', help="Path to LLVM build directory")
parser.add_argument('IRFile', help="Path to the input IR file")
args=parser.parse_args()

# Check if the binaries exist.
build_dir=check_path(args.BuildDir)
ir_file=check_path(args.IRFile)
llc_bin=check_bin(build_dir, 'llc')
opt_bin=check_bin(build_dir, 'opt')
bugpoint_bin=check_bin(build_dir, 'bugpoint')

# Run llc to see if GlobalISel fails.
log('Running llc...')
res=run_llc(llc_bin, ir_file)
ifres==0:
log_err("Expected failure")
raise
hr()
log('GlobalISel failed, {}: {}.'.format(res[0], res[1]))
tmp=tempfile.NamedTemporaryFile()
log('Writing error to {} for bugpoint.'.format(tmp.name))
tmp.write(';'.join(res))
tmp.flush()
hr()

# Run bugpoint.
log('Running bugpoint...')
run_bugpoint(bugpoint_bin, llc_bin, opt_bin, tmp.name, ir_file)
hr()
log('Done!')
hr()
output_file='bugpoint-reduced-simplified.bc'
log('Run llvm-dis to disassemble the output:')
log('$ {}/bin/llvm-dis -o - {}'.format(build_dir, output_file))
log('Run llc to reproduce the problem:')
log('$ {}/bin/llc -o - -global-isel '
'-pass-remarks-missed=gisel {}'.format(build_dir, output_file))


if__name__=='__main__':
main()