File size: 8,608 Bytes
d289b5b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 | #!/usr/bin/env python3
# Copyright 2019 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
################################################################################
"""Use git bisect to find the Clang/LLVM commit causing a regression."""
import logging
import os
import re
import shutil
import subprocess
import sys
def execute(command, *args, expect_zero=True, **kwargs):
"""Execute |command| and return the returncode, stdout and stderr."""
kwargs['stdout'] = subprocess.PIPE
kwargs['stderr'] = subprocess.PIPE
logging.debug('Running command: "%s"', str(command))
process = subprocess.Popen(command, *args, **kwargs)
stdout, stderr = process.communicate()
stdout = stdout.decode('utf-8')
stderr = stderr.decode('utf-8')
retcode = process.returncode
logging.info('Command: "%s" returned: %d.\nStdout: %s.\nStderr: %s',
str(command), retcode, stdout, stderr)
if expect_zero and retcode != 0:
raise subprocess.CalledProcessError(retcode, command)
return retcode, stdout, stderr
def search_bisect_output(output):
"""Search |output| for a message indicating the culprit commit has been
found."""
# TODO(metzman): Is it necessary to look for "good"?
culprit_regex = re.compile('([a-z0-9]{40}) is the first (good|bad) commit')
match = re.match(culprit_regex, output)
return match.group(1) if match is not None else None
class GitRepo:
"""Class for executing commmands on a git repo."""
def __init__(self, repo_dir):
self.repo_dir = repo_dir
def do_command(self, git_subcommand):
"""Execute a |git_subcommand| (a list of strings)."""
command = ['git', '-C', self.repo_dir] + git_subcommand
return execute(command)
def test_commit(self, test_command):
"""Build LLVM at the currently checkedout commit, then run |test_command|.
If returncode is 0 run 'git bisect good' otherwise return 'git bisect bad'.
Return None if bisect didn't finish yet. Return the culprit commit if it
does."""
build_clang(self.repo_dir)
retcode, _, _ = execute(test_command, shell=True, expect_zero=False)
if retcode == 0:
retcode, stdout, _ = self.do_bisect_command('good')
else:
retcode, stdout, _ = self.do_bisect_command('bad')
return search_bisect_output(stdout)
def bisect(self, good_commit, bad_commit, test_command):
"""Do git bisect assuming |good_commit| is good, |bad_commit| is bad and
|test_command| is an oracle. Return the culprit commit."""
self.bisect_start(good_commit, bad_commit, test_command)
result = self.test_commit(test_command)
while result is None:
result = self.test_commit(test_command)
return result
def bisect_start(self, good_commit, bad_commit, test_command):
"""Start doing git bisect."""
self.do_bisect_command('start')
# Do bad commit first since it is more likely to be recent.
self.test_start_commit(bad_commit, 'bad', test_command)
self.test_start_commit(good_commit, 'good', test_command)
def do_bisect_command(self, subcommand):
"""Execute a git bisect |subcommand| (string) and return the result."""
return self.do_command(['bisect', subcommand])
def test_start_commit(self, commit, label, test_command):
"""Use |test_command| to test the first good or bad |commit| (depending on
|label|)."""
assert label in ('good', 'bad'), label
self.do_command(['checkout', commit])
build_clang(self.repo_dir)
retcode, _, _ = execute(test_command, shell=True, expect_zero=False)
if label == 'good' and retcode != 0:
raise BisectError('Test command "%s" returns %d on first good commit %s' %
(test_command, retcode, commit))
if label == 'bad' and retcode == 0:
raise BisectError('Test command "%s" returns %d on first bad commit %s' %
(test_command, retcode, commit))
self.do_bisect_command(label)
class BisectError(Exception):
"""Error that was encountered during bisection."""
def get_clang_build_env():
"""Get an environment for building Clang."""
env = os.environ.copy()
for variable in ['CXXFLAGS', 'CFLAGS']:
if variable in env:
del env[variable]
return env
def install_clang_build_deps():
"""Instal dependencies necessary to build clang."""
execute([
'apt-get', 'install', '-y', 'build-essential', 'make', 'cmake',
'ninja-build', 'git', 'subversion', 'g++-multilib'
])
def clone_with_retries(repo, local_path, num_retries=10):
"""Clone |repo| to |local_path| if it doesn't exist already. Try up to
|num_retries| times. Return False if unable to checkout."""
if os.path.isdir(local_path):
return
for _ in range(num_retries):
if os.path.isdir(local_path):
shutil.rmtree(local_path)
retcode, _, _ = execute(['git', 'clone', repo, local_path],
expect_zero=False)
if retcode == 0:
return
raise Exception('Could not checkout %s.' % repo)
def get_clang_target_arch():
"""Get target architecture we want clang to target when we build it."""
_, arch, _ = execute(['uname', '-m'])
if 'x86_64' in arch:
return 'X86'
if 'aarch64' in arch:
return 'AArch64'
raise Exception('Unsupported target: %s.' % arch)
def prepare_build(llvm_project_path):
"""Prepare to build clang."""
llvm_build_dir = os.path.join(os.getenv('WORK'), 'llvm-build')
if not os.path.exists(llvm_build_dir):
os.mkdir(llvm_build_dir)
execute([
'cmake', '-G', 'Ninja', '-DLIBCXX_ENABLE_SHARED=OFF',
'-DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=ON', '-DLIBCXXABI_ENABLE_SHARED=OFF',
'-DCMAKE_BUILD_TYPE=Release',
'-DLLVM_ENABLE_PROJECTS=libcxx;libcxxabi;compiler-rt;clang',
'-DLLVM_TARGETS_TO_BUILD=' + get_clang_target_arch(),
os.path.join(llvm_project_path, 'llvm')
],
env=get_clang_build_env(),
cwd=llvm_build_dir)
return llvm_build_dir
def build_clang(llvm_project_path):
"""Checkout, build and install Clang."""
# TODO(metzman): Merge Python checkout and build code with
# checkout_build_install_llvm.sh.
# TODO(metzman): Look into speeding this process using ccache.
# TODO(metzman): Make this program capable of handling MSAN and i386 Clang
# regressions.
llvm_build_dir = prepare_build(llvm_project_path)
execute(['ninja', '-C', llvm_build_dir, 'install'], env=get_clang_build_env())
def find_culprit_commit(test_command, good_commit, bad_commit):
"""Returns the culprit LLVM commit that introduced a bug revealed by running
|test_command|. Uses git bisect and treats |good_commit| as the first latest
known good commit and |bad_commit| as the first known bad commit."""
llvm_project_path = os.path.join(os.getenv('SRC'), 'llvm-project')
clone_with_retries('https://github.com/llvm/llvm-project.git',
llvm_project_path)
git_repo = GitRepo(llvm_project_path)
result = git_repo.bisect(good_commit, bad_commit, test_command)
print('Culprit commit', result)
return result
def main():
# pylint: disable=line-too-long
"""Finds the culprit LLVM commit that introduced a clang regression.
Can be tested using this command in a libsodium shell:
python3 bisect_clang.py "cd /src/libsodium; make clean; cd -; compile && /out/secret_key_auth_fuzzer -runs=100" \
f7e52fbdb5a7af8ea0808e98458b497125a5eca1 \
8288453f6aac05080b751b680455349e09d49825
"""
# pylint: enable=line-too-long
# TODO(metzman): Check CFLAGS for things like -fsanitize=fuzzer-no-link.
# TODO(metzman): Allow test_command to be optional and for just build.sh to be
# used instead.
test_command = sys.argv[1]
# TODO(metzman): Add in more automation so that the script can automatically
# determine the commits used in last Clang roll.
good_commit = sys.argv[2]
bad_commit = sys.argv[3]
# TODO(metzman): Make verbosity configurable.
logging.getLogger().setLevel(logging.DEBUG)
install_clang_build_deps()
find_culprit_commit(test_command, good_commit, bad_commit)
return 0
if __name__ == '__main__':
sys.exit(main())
|