Remove tools/clang (this will break things temporarily).

tools/clang/scripts/update.py

Index: tools/clang/scripts/update.py
diff --git a/tools/clang/scripts/update.py b/tools/clang/scripts/update.py
deleted file mode 100755
index 38c0e779d212ffb588f0d2d54d535e409ad03f41..0000000000000000000000000000000000000000
--- a/tools/clang/scripts/update.py
+++ /dev/null
@@ -1,751 +0,0 @@
-#!/usr/bin/env python
-# Copyright (c) 2012 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-"""Windows can't run .sh files, so this is a Python implementation of
-update.sh. This script should replace update.sh on all platforms eventually."""
-
-import argparse
-import contextlib
-import cStringIO
-import glob
-import os
-import pipes
-import re
-import shutil
-import subprocess
-import stat
-import sys
-import tarfile
-import time
-import urllib2
-import zipfile
-
-# Do NOT CHANGE this if you don't know what you're doing -- see
-# https://code.google.com/p/chromium/wiki/UpdatingClang
-# Reverting problematic clang rolls is safe, though.
-# Note: this revision is only used for Windows. Other platforms use update.sh.
-# TODO(thakis): Use the same revision on Windows and non-Windows.
-# TODO(thakis): Remove update.sh, use update.py everywhere.
-LLVM_WIN_REVISION = '247874'
-
-use_head_revision = 'LLVM_FORCE_HEAD_REVISION' in os.environ
-if use_head_revision:
-  LLVM_WIN_REVISION = 'HEAD'
-
-# This is incremented when pushing a new build of Clang at the same revision.
-CLANG_SUB_REVISION=1
-
-PACKAGE_VERSION = "%s-%s" % (LLVM_WIN_REVISION, CLANG_SUB_REVISION)
-
-# Path constants. (All of these should be absolute paths.)
-THIS_DIR = os.path.abspath(os.path.dirname(__file__))
-CHROMIUM_DIR = os.path.abspath(os.path.join(THIS_DIR, '..', '..', '..'))
-THIRD_PARTY_DIR = os.path.join(CHROMIUM_DIR, 'third_party')
-LLVM_DIR = os.path.join(THIRD_PARTY_DIR, 'llvm')
-LLVM_BOOTSTRAP_DIR = os.path.join(THIRD_PARTY_DIR, 'llvm-bootstrap')
-LLVM_BOOTSTRAP_INSTALL_DIR = os.path.join(THIRD_PARTY_DIR,
-                                          'llvm-bootstrap-install')
-CHROME_TOOLS_SHIM_DIR = os.path.join(LLVM_DIR, 'tools', 'chrometools')
-LLVM_BUILD_DIR = os.path.join(CHROMIUM_DIR, 'third_party', 'llvm-build',
-                              'Release+Asserts')
-COMPILER_RT_BUILD_DIR = os.path.join(LLVM_BUILD_DIR, '32bit-compiler-rt')
-CLANG_DIR = os.path.join(LLVM_DIR, 'tools', 'clang')
-LLD_DIR = os.path.join(LLVM_DIR, 'tools', 'lld')
-COMPILER_RT_DIR = os.path.join(LLVM_DIR, 'projects', 'compiler-rt')
-LIBCXX_DIR = os.path.join(LLVM_DIR, 'projects', 'libcxx')
-LIBCXXABI_DIR = os.path.join(LLVM_DIR, 'projects', 'libcxxabi')
-LLVM_BUILD_TOOLS_DIR = os.path.abspath(
-    os.path.join(LLVM_DIR, '..', 'llvm-build-tools'))
-STAMP_FILE = os.path.join(LLVM_DIR, '..', 'llvm-build', 'cr_build_revision')
-BINUTILS_DIR = os.path.join(THIRD_PARTY_DIR, 'binutils')
-VERSION = '3.8.0'
-
-# URL for pre-built binaries.
-CDS_URL = 'https://commondatastorage.googleapis.com/chromium-browser-clang'
-
-LLVM_REPO_URL='https://llvm.org/svn/llvm-project'
-if 'LLVM_REPO_URL' in os.environ:
-  LLVM_REPO_URL = os.environ['LLVM_REPO_URL']
-
-
-def DownloadUrl(url, output_file):
-  """Download url into output_file."""
-  CHUNK_SIZE = 4096
-  TOTAL_DOTS = 10
-  sys.stdout.write('Downloading %s ' % url)
-  sys.stdout.flush()
-  response = urllib2.urlopen(url)
-  total_size = int(response.info().getheader('Content-Length').strip())
-  bytes_done = 0
-  dots_printed = 0
-  while True:
-    chunk = response.read(CHUNK_SIZE)
-    if not chunk:
-      break
-    output_file.write(chunk)
-    bytes_done += len(chunk)
-    num_dots = TOTAL_DOTS * bytes_done / total_size
-    sys.stdout.write('.' * (num_dots - dots_printed))
-    sys.stdout.flush()
-    dots_printed = num_dots
-  print ' Done.'
-
-
-def ReadStampFile():
-  """Return the contents of the stamp file, or '' if it doesn't exist."""
-  try:
-    with open(STAMP_FILE, 'r') as f:
-      return f.read()
-  except IOError:
-    return ''
-
-
-def WriteStampFile(s):
-  """Write s to the stamp file."""
-  if not os.path.exists(os.path.dirname(STAMP_FILE)):
-    os.makedirs(os.path.dirname(STAMP_FILE))
-  with open(STAMP_FILE, 'w') as f:
-    f.write(s)
-
-
-def GetSvnRevision(svn_repo):
-  """Returns current revision of the svn repo at svn_repo."""
-  svn_info = subprocess.check_output('svn info ' + svn_repo, shell=True)
-  m = re.search(r'Revision: (\d+)', svn_info)
-  return m.group(1)
-
-
-def RmTree(dir):
-  """Delete dir."""
-  def ChmodAndRetry(func, path, _):
-    # Subversion can leave read-only files around.
-    if not os.access(path, os.W_OK):
-      os.chmod(path, stat.S_IWUSR)
-      return func(path)
-    raise
-
-  shutil.rmtree(dir, onerror=ChmodAndRetry)
-
-
-def RunCommand(command, msvc_arch=None, env=None, fail_hard=True):
-  """Run command and return success (True) or failure; or if fail_hard is
-     True, exit on failure.  If msvc_arch is set, runs the command in a
-     shell with the msvc tools for that architecture."""
-
-  if msvc_arch and sys.platform == 'win32':
-    command = GetVSVersion().SetupScript(msvc_arch) + ['&&'] + command
-
-  # https://docs.python.org/2/library/subprocess.html:
-  # "On Unix with shell=True [...] if args is a sequence, the first item
-  # specifies the command string, and any additional items will be treated as
-  # additional arguments to the shell itself.  That is to say, Popen does the
-  # equivalent of:
-  #   Popen(['/bin/sh', '-c', args[0], args[1], ...])"
-  #
-  # We want to pass additional arguments to command[0], not to the shell,
-  # so manually join everything into a single string.
-  # Annoyingly, for "svn co url c:\path", pipes.quote() thinks that it should
-  # quote c:\path but svn can't handle quoted paths on Windows.  Since on
-  # Windows follow-on args are passed to args[0] instead of the shell, don't
-  # do the single-string transformation there.
-  if sys.platform != 'win32':
-    command = ' '.join([pipes.quote(c) for c in command])
-  print 'Running', command
-  if subprocess.call(command, env=env, shell=True) == 0:
-    return True
-  print 'Failed.'
-  if fail_hard:
-    sys.exit(1)
-  return False
-
-
-def CopyFile(src, dst):
-  """Copy a file from src to dst."""
-  shutil.copy(src, dst)
-  print "Copying %s to %s" % (src, dst)
-
-
-def CopyDirectoryContents(src, dst, filename_filter=None):
-  """Copy the files from directory src to dst
-  with an optional filename filter."""
-  if not os.path.exists(dst):
-    os.makedirs(dst)
-  for root, _, files in os.walk(src):
-    for f in files:
-      if filename_filter and not re.match(filename_filter, f):
-        continue
-      CopyFile(os.path.join(root, f), dst)
-
-
-def Checkout(name, url, dir):
-  """Checkout the SVN module at url into dir. Use name for the log message."""
-  print "Checking out %s r%s into '%s'" % (name, LLVM_WIN_REVISION, dir)
-
-  command = ['svn', 'checkout', '--force', url + '@' + LLVM_WIN_REVISION, dir]
-  if RunCommand(command, fail_hard=False):
-    return
-
-  if os.path.isdir(dir):
-    print "Removing %s." % (dir)
-    RmTree(dir)
-
-  print "Retrying."
-  RunCommand(command)
-
-
-def RevertPreviouslyPatchedFiles():
-  print 'Reverting previously patched files'
-  files = [
-    '%(clang)s/test/Index/crash-recovery-modules.m',
-    '%(clang)s/unittests/libclang/LibclangTest.cpp',
-    '%(compiler_rt)s/lib/asan/asan_rtl.cc',
-    '%(compiler_rt)s/test/asan/TestCases/Linux/new_array_cookie_test.cc',
-    '%(llvm)s/test/DebugInfo/gmlt.ll',
-    '%(llvm)s/lib/CodeGen/SpillPlacement.cpp',
-    '%(llvm)s/lib/CodeGen/SpillPlacement.h',
-    '%(llvm)s/lib/Transforms/Instrumentation/MemorySanitizer.cpp',
-    '%(clang)s/test/Driver/env.c',
-    '%(clang)s/lib/Frontend/InitPreprocessor.cpp',
-    '%(clang)s/test/Frontend/exceptions.c',
-    '%(clang)s/test/Preprocessor/predefined-exceptions.m',
-    '%(llvm)s/test/Bindings/Go/go.test',
-    '%(clang)s/lib/Parse/ParseExpr.cpp',
-    '%(clang)s/lib/Parse/ParseTemplate.cpp',
-    '%(clang)s/lib/Sema/SemaDeclCXX.cpp',
-    '%(clang)s/lib/Sema/SemaExprCXX.cpp',
-    '%(clang)s/test/SemaCXX/default2.cpp',
-    '%(clang)s/test/SemaCXX/typo-correction-delayed.cpp',
-    '%(compiler_rt)s/lib/sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc',
-    '%(compiler_rt)s/test/tsan/signal_segv_handler.cc',
-    '%(compiler_rt)s/lib/sanitizer_common/sanitizer_coverage_libcdep.cc',
-    '%(compiler_rt)s/cmake/config-ix.cmake',
-    '%(compiler_rt)s/CMakeLists.txt',
-    '%(compiler_rt)s/lib/ubsan/ubsan_platform.h',
-    ]
-  for f in files:
-    f = f % {
-        'clang': CLANG_DIR,
-        'compiler_rt': COMPILER_RT_DIR,
-        'llvm': LLVM_DIR,
-        }
-    if os.path.exists(f):
-      os.remove(f)  # For unversioned files.
-      RunCommand(['svn', 'revert', f])
-
-
-def ApplyLocalPatches():
-  # There's no patch program on Windows by default.  We don't need patches on
-  # Windows yet, and maybe this not working on Windows will motivate us to
-  # remove patches over time.
-  assert sys.platform != 'win32'
-
-  # No patches.
-
-
-def DeleteChromeToolsShim():
-  OLD_SHIM_DIR = os.path.join(LLVM_DIR, 'tools', 'zzz-chrometools')
-  shutil.rmtree(OLD_SHIM_DIR, ignore_errors=True)
-  shutil.rmtree(CHROME_TOOLS_SHIM_DIR, ignore_errors=True)
-
-
-def CreateChromeToolsShim():
-  """Hooks the Chrome tools into the LLVM build.
-
-  Several Chrome tools have dependencies on LLVM/Clang libraries. The LLVM build
-  detects implicit tools in the tools subdirectory, so this helper install a
-  shim CMakeLists.txt that forwards to the real directory for the Chrome tools.
-
-  Note that the shim directory name intentionally has no - or _. The implicit
-  tool detection logic munges them in a weird way."""
-  assert not any(i in os.path.basename(CHROME_TOOLS_SHIM_DIR) for i in '-_')
-  os.mkdir(CHROME_TOOLS_SHIM_DIR)
-  with file(os.path.join(CHROME_TOOLS_SHIM_DIR, 'CMakeLists.txt'), 'w') as f:
-    f.write('# Automatically generated by tools/clang/scripts/update.py. ' +
-            'Do not edit.\n')
-    f.write('# Since tools/clang is located in another directory, use the \n')
-    f.write('# two arg version to specify where build artifacts go. CMake\n')
-    f.write('# disallows reuse of the same binary dir for multiple source\n')
-    f.write('# dirs, so the build artifacts need to go into a subdirectory.\n')
-    f.write('# dirs, so the build artifacts need to go into a subdirectory.\n')
-    f.write('if (CHROMIUM_TOOLS_SRC)\n')
-    f.write('  add_subdirectory(${CHROMIUM_TOOLS_SRC} ' +
-              '${CMAKE_CURRENT_BINARY_DIR}/a)\n')
-    f.write('endif (CHROMIUM_TOOLS_SRC)\n')
-
-
-def AddCMakeToPath():
-  """Download CMake and add it to PATH."""
-  if sys.platform == 'win32':
-    zip_name = 'cmake-3.2.2-win32-x86.zip'
-    cmake_dir = os.path.join(LLVM_BUILD_TOOLS_DIR,
-                             'cmake-3.2.2-win32-x86', 'bin')
-  else:
-    suffix = 'Darwin' if sys.platform == 'darwin' else 'Linux'
-    zip_name = 'cmake310_%s.tgz' % suffix
-    cmake_dir = os.path.join(LLVM_BUILD_TOOLS_DIR, 'cmake310', 'bin')
-  if not os.path.exists(cmake_dir):
-    if not os.path.exists(LLVM_BUILD_TOOLS_DIR):
-      os.makedirs(LLVM_BUILD_TOOLS_DIR)
-    # The cmake archive is smaller than 20 MB, small enough to keep in memory:
-    with contextlib.closing(cStringIO.StringIO()) as f:
-      DownloadUrl(CDS_URL + '/tools/' + zip_name, f)
-      f.seek(0)
-      if zip_name.endswith('.zip'):
-        zipfile.ZipFile(f).extractall(path=LLVM_BUILD_TOOLS_DIR)
-      else:
-        tarfile.open(mode='r:gz', fileobj=f).extractall(path=
-            LLVM_BUILD_TOOLS_DIR)
-  os.environ['PATH'] = cmake_dir + os.pathsep + os.environ.get('PATH', '')
-
-vs_version = None
-def GetVSVersion():
-  global vs_version
-  if vs_version:
-    return vs_version
-
-  # Try using the toolchain in depot_tools.
-  # This sets environment variables used by SelectVisualStudioVersion below.
-  sys.path.append(os.path.join(CHROMIUM_DIR, 'build'))
-  import vs_toolchain
-  vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()
-
-  # Use gyp to find the MSVS installation, either in depot_tools as per above,
-  # or a system-wide installation otherwise.
-  sys.path.append(os.path.join(CHROMIUM_DIR, 'tools', 'gyp', 'pylib'))
-  import gyp.MSVSVersion
-  vs_version = gyp.MSVSVersion.SelectVisualStudioVersion('2013')
-  return vs_version
-
-
-def UpdateClang(args):
-  print 'Updating Clang to %s...' % PACKAGE_VERSION
-  if ReadStampFile() == PACKAGE_VERSION:
-    print 'Already up to date.'
-    return 0
-
-  # Reset the stamp file in case the build is unsuccessful.
-  WriteStampFile('')
-
-  if not args.force_local_build:
-    cds_file = "clang-%s.tgz" %  PACKAGE_VERSION
-    cds_full_url = CDS_URL + '/Win/' + cds_file
-
-    # Check if there's a prebuilt binary and if so just fetch that. That's
-    # faster, and goma relies on having matching binary hashes on client and
-    # server too.
-    print 'Trying to download prebuilt clang'
-
-    # clang packages are smaller than 50 MB, small enough to keep in memory.
-    with contextlib.closing(cStringIO.StringIO()) as f:
-      try:
-        DownloadUrl(cds_full_url, f)
-        f.seek(0)
-        # TODO(thakis): Delete LLVM_BUILD_DIR before extracting.
-        tarfile.open(mode='r:gz', fileobj=f).extractall(path=LLVM_BUILD_DIR)
-        print 'clang %s unpacked' % PACKAGE_VERSION
-        # Download the gold plugin if requested to by an environment variable.
-        # This is used by the CFI ClusterFuzz bot.
-        if 'LLVM_DOWNLOAD_GOLD_PLUGIN' in os.environ:
-          RunCommand(['python', CHROMIUM_DIR+'/build/download_gold_plugin.py'])
-        WriteStampFile(PACKAGE_VERSION)
-        return 0
-      except urllib2.HTTPError:
-        print 'Did not find prebuilt clang %s, building locally' % cds_file
-
-  AddCMakeToPath()
-
-  RevertPreviouslyPatchedFiles()
-  DeleteChromeToolsShim()
-
-  Checkout('LLVM', LLVM_REPO_URL + '/llvm/trunk', LLVM_DIR)
-  Checkout('Clang', LLVM_REPO_URL + '/cfe/trunk', CLANG_DIR)
-  if sys.platform == 'win32':
-    Checkout('LLD', LLVM_REPO_URL + '/lld/trunk', LLD_DIR)
-  Checkout('compiler-rt', LLVM_REPO_URL + '/compiler-rt/trunk', COMPILER_RT_DIR)
-  if sys.platform == 'darwin':
-    # clang needs a libc++ checkout, else -stdlib=libc++ won't find includes
-    # (i.e. this is needed for bootstrap builds).
-    Checkout('libcxx', LLVM_REPO_URL + '/libcxx/trunk', LIBCXX_DIR)
-    # While we're bundling our own libc++ on OS X, we need to compile libc++abi
-    # into it too (since OS X 10.6 doesn't have libc++abi.dylib either).
-    Checkout('libcxxabi', LLVM_REPO_URL + '/libcxxabi/trunk', LIBCXXABI_DIR)
-
-  if args.with_patches and sys.platform != 'win32':
-    ApplyLocalPatches()
-
-  cc, cxx = None, None
-  libstdcpp = None
-  if args.gcc_toolchain:  # This option is only used on Linux.
-    # Use the specified gcc installation for building.
-    cc = os.path.join(args.gcc_toolchain, 'bin', 'gcc')
-    cxx = os.path.join(args.gcc_toolchain, 'bin', 'g++')
-
-    if not os.access(cc, os.X_OK):
-      print 'Invalid --gcc-toolchain: "%s"' % args.gcc_toolchain
-      print '"%s" does not appear to be valid.' % cc
-      return 1
-
-    # Set LD_LIBRARY_PATH to make auxiliary targets (tablegen, bootstrap
-    # compiler, etc.) find the .so.
-    libstdcpp = subprocess.check_output(
-        [cxx, '-print-file-name=libstdc++.so.6']).rstrip()
-    os.environ['LD_LIBRARY_PATH'] = os.path.dirname(libstdcpp)
-
-  cflags = cxxflags = ldflags = []
-
-  # LLVM uses C++11 starting in llvm 3.5. On Linux, this means libstdc++4.7+ is
-  # needed, on OS X it requires libc++. clang only automatically links to libc++
-  # when targeting OS X 10.9+, so add stdlib=libc++ explicitly so clang can run
-  # on OS X versions as old as 10.7.
-  # TODO(thakis): Some bots are still on 10.6 (nacl...), so for now bundle
-  # libc++.dylib.  Remove this once all bots are on 10.7+, then use
-  # -DLLVM_ENABLE_LIBCXX=ON and change deployment_target to 10.7.
-  deployment_target = ''
-
-  if sys.platform == 'darwin':
-    # When building on 10.9, /usr/include usually doesn't exist, and while
-    # Xcode's clang automatically sets a sysroot, self-built clangs don't.
-    cflags = ['-isysroot', subprocess.check_output(
-        ['xcrun', '--show-sdk-path']).rstrip()]
-    cxxflags = ['-stdlib=libc++', '-nostdinc++',
-                '-I' + os.path.join(LIBCXX_DIR, 'include')] + cflags
-    if args.bootstrap:
-      deployment_target = '10.6'
-
-  base_cmake_args = ['-GNinja',
-                     '-DCMAKE_BUILD_TYPE=Release',
-                     '-DLLVM_ENABLE_ASSERTIONS=ON',
-                     '-DLLVM_ENABLE_THREADS=OFF',
-                     ]
-
-  if args.bootstrap:
-    print 'Building bootstrap compiler'
-    if not os.path.exists(LLVM_BOOTSTRAP_DIR):
-      os.makedirs(LLVM_BOOTSTRAP_DIR)
-    os.chdir(LLVM_BOOTSTRAP_DIR)
-    bootstrap_args = base_cmake_args + [
-        '-DLLVM_TARGETS_TO_BUILD=host',
-        '-DCMAKE_INSTALL_PREFIX=' + LLVM_BOOTSTRAP_INSTALL_DIR,
-        '-DCMAKE_C_FLAGS=' + ' '.join(cflags),
-        '-DCMAKE_CXX_FLAGS=' + ' '.join(cxxflags),
-        ]
-    if cc is not None:  bootstrap_args.append('-DCMAKE_C_COMPILER=' + cc)
-    if cxx is not None: bootstrap_args.append('-DCMAKE_CXX_COMPILER=' + cxx)
-    RunCommand(['cmake'] + bootstrap_args + [LLVM_DIR], msvc_arch='x64')
-    RunCommand(['ninja'], msvc_arch='x64')
-    if args.run_tests:
-      RunCommand(['ninja', 'check-all'], msvc_arch='x64')
-    RunCommand(['ninja', 'install'], msvc_arch='x64')
-    if args.gcc_toolchain:
-      # Copy that gcc's stdlibc++.so.6 to the build dir, so the bootstrap
-      # compiler can start.
-      CopyFile(libstdcpp, os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'lib'))
-
-    if sys.platform == 'win32':
-      cc = os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'bin', 'clang-cl.exe')
-      cxx = os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'bin', 'clang-cl.exe')
-      # CMake has a hard time with backslashes in compiler paths:
-      # https://stackoverflow.com/questions/13050827
-      cc = cc.replace('\\', '/')
-      cxx = cxx.replace('\\', '/')
-    else:
-      cc = os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'bin', 'clang')
-      cxx = os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'bin', 'clang++')
-
-    if args.gcc_toolchain:
-      # Tell the bootstrap compiler to use a specific gcc prefix to search
-      # for standard library headers and shared object files.
-      cflags = ['--gcc-toolchain=' + args.gcc_toolchain]
-      cxxflags = ['--gcc-toolchain=' + args.gcc_toolchain]
-    print 'Building final compiler'
-
-  if sys.platform == 'darwin':
-    # Build libc++.dylib while some bots are still on OS X 10.6.
-    libcxxbuild = os.path.join(LLVM_BUILD_DIR, 'libcxxbuild')
-    if os.path.isdir(libcxxbuild):
-      RmTree(libcxxbuild)
-    libcxxflags = ['-O3', '-std=c++11', '-fstrict-aliasing']
-
-    # libcxx and libcxxabi both have a file stdexcept.cpp, so put their .o files
-    # into different subdirectories.
-    os.makedirs(os.path.join(libcxxbuild, 'libcxx'))
-    os.chdir(os.path.join(libcxxbuild, 'libcxx'))
-    RunCommand(['c++', '-c'] + cxxflags + libcxxflags +
-                glob.glob(os.path.join(LIBCXX_DIR, 'src', '*.cpp')))
-
-    os.makedirs(os.path.join(libcxxbuild, 'libcxxabi'))
-    os.chdir(os.path.join(libcxxbuild, 'libcxxabi'))
-    RunCommand(['c++', '-c'] + cxxflags + libcxxflags +
-               glob.glob(os.path.join(LIBCXXABI_DIR, 'src', '*.cpp')) +
-               ['-I' + os.path.join(LIBCXXABI_DIR, 'include')])
-
-    os.chdir(libcxxbuild)
-    libdir = os.path.join(LIBCXX_DIR, 'lib')
-    RunCommand(['cc'] + glob.glob('libcxx/*.o') + glob.glob('libcxxabi/*.o') +
-        ['-o', 'libc++.1.dylib', '-dynamiclib', '-nodefaultlibs',
-         '-current_version', '1', '-compatibility_version', '1', '-lSystem',
-         '-install_name', '@executable_path/libc++.dylib',
-         '-Wl,-unexported_symbols_list,' + libdir + '/libc++unexp.exp',
-         '-Wl,-force_symbols_not_weak_list,' + libdir + '/notweak.exp',
-         '-Wl,-force_symbols_weak_list,' + libdir + '/weak.exp'])
-    if os.path.exists('libc++.dylib'):
-      os.remove('libc++.dylib')
-    os.symlink('libc++.1.dylib', 'libc++.dylib')
-    ldflags += ['-stdlib=libc++', '-L' + libcxxbuild]
-
-    if args.bootstrap:
-      # Now that the libc++ headers have been installed and libc++.dylib is
-      # built, delete the libc++ checkout again so that it's not part of the
-      # main build below -- the libc++(abi) tests don't pass on OS X in
-      # bootstrap builds (http://llvm.org/PR24068)
-      RmTree(LIBCXX_DIR)
-      RmTree(LIBCXXABI_DIR)
-      cxxflags = ['-stdlib=libc++', '-nostdinc++',
-                  '-I' + os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR,
-                                      'include/c++/v1')
-                  ] + cflags
-
-  # Build clang.
-  binutils_incdir = ''
-  if sys.platform.startswith('linux'):
-    binutils_incdir = os.path.join(BINUTILS_DIR, 'Linux_x64/Release/include')
-
-  # If building at head, define a macro that plugins can use for #ifdefing
-  # out code that builds at head, but not at LLVM_WIN_REVISION or vice versa.
-  if use_head_revision:
-    cflags += ['-DLLVM_FORCE_HEAD_REVISION']
-    cxxflags += ['-DLLVM_FORCE_HEAD_REVISION']
-
-  CreateChromeToolsShim()
-
-  deployment_env = None
-  if deployment_target:
-    deployment_env = os.environ.copy()
-    deployment_env['MACOSX_DEPLOYMENT_TARGET'] = deployment_target
-
-  cmake_args = base_cmake_args + [
-      '-DLLVM_BINUTILS_INCDIR=' + binutils_incdir,
-      '-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly',
-      '-DCMAKE_C_FLAGS=' + ' '.join(cflags),
-      '-DCMAKE_CXX_FLAGS=' + ' '.join(cxxflags),
-      '-DCMAKE_EXE_LINKER_FLAGS=' + ' '.join(ldflags),
-      '-DCMAKE_SHARED_LINKER_FLAGS=' + ' '.join(ldflags),
-      '-DCMAKE_MODULE_LINKER_FLAGS=' + ' '.join(ldflags),
-      '-DCMAKE_INSTALL_PREFIX=' + LLVM_BUILD_DIR,
-      '-DCHROMIUM_TOOLS_SRC=%s' % os.path.join(CHROMIUM_DIR, 'tools', 'clang'),
-      '-DCHROMIUM_TOOLS=%s' % ';'.join(args.tools)]
-  # TODO(thakis): Unconditionally append this to base_cmake_args instead once
-  # compiler-rt can build with clang-cl on Windows (http://llvm.org/PR23698)
-  cc_args = base_cmake_args if sys.platform != 'win32' else cmake_args
-  if cc is not None:  cc_args.append('-DCMAKE_C_COMPILER=' + cc)
-  if cxx is not None: cc_args.append('-DCMAKE_CXX_COMPILER=' + cxx)
-
-  if not os.path.exists(LLVM_BUILD_DIR):
-    os.makedirs(LLVM_BUILD_DIR)
-  os.chdir(LLVM_BUILD_DIR)
-  RunCommand(['cmake'] + cmake_args + [LLVM_DIR],
-             msvc_arch='x64', env=deployment_env)
-
-  if args.gcc_toolchain:
-    # Copy in the right stdlibc++.so.6 so clang can start.
-    if not os.path.exists(os.path.join(LLVM_BUILD_DIR, 'lib')):
-      os.mkdir(os.path.join(LLVM_BUILD_DIR, 'lib'))
-    libstdcpp = subprocess.check_output(
-        [cxx] + cxxflags + ['-print-file-name=libstdc++.so.6']).rstrip()
-    CopyFile(libstdcpp, os.path.join(LLVM_BUILD_DIR, 'lib'))
-
-  RunCommand(['ninja'], msvc_arch='x64')
-
-  if args.tools:
-    # If any Chromium tools were built, install those now.
-    RunCommand(['ninja', 'cr-install'], msvc_arch='x64')
-
-  if sys.platform == 'darwin':
-    CopyFile(os.path.join(LLVM_BUILD_DIR, 'libc++.1.dylib'),
-             os.path.join(LLVM_BUILD_DIR, 'bin'))
-    # See http://crbug.com/256342
-    RunCommand(['strip', '-x', os.path.join(LLVM_BUILD_DIR, 'bin', 'clang')])
-  elif sys.platform.startswith('linux'):
-    RunCommand(['strip', os.path.join(LLVM_BUILD_DIR, 'bin', 'clang')])
-
-  # Do an x86 build of compiler-rt to get the 32-bit ASan run-time.
-  # TODO(hans): Remove once the regular build above produces this.
-  if not os.path.exists(COMPILER_RT_BUILD_DIR):
-    os.makedirs(COMPILER_RT_BUILD_DIR)
-  os.chdir(COMPILER_RT_BUILD_DIR)
-  # TODO(thakis): Add this once compiler-rt can build with clang-cl (see
-  # above).
-  #if args.bootstrap and sys.platform == 'win32':
-    # The bootstrap compiler produces 64-bit binaries by default.
-    #cflags += ['-m32']
-    #cxxflags += ['-m32']
-  compiler_rt_args = base_cmake_args + [
-      '-DCMAKE_C_FLAGS=' + ' '.join(cflags),
-      '-DCMAKE_CXX_FLAGS=' + ' '.join(cxxflags)]
-  if sys.platform != 'win32':
-    compiler_rt_args += ['-DLLVM_CONFIG_PATH=' +
-                         os.path.join(LLVM_BUILD_DIR, 'bin', 'llvm-config'),
-                        '-DSANITIZER_MIN_OSX_VERSION="10.7"']
-  RunCommand(['cmake'] + compiler_rt_args + [LLVM_DIR],
-              msvc_arch='x86', env=deployment_env)
-  RunCommand(['ninja', 'compiler-rt'], msvc_arch='x86')
-
-  # TODO(hans): Make this (and the .gypi and .isolate files) version number
-  # independent.
-  if sys.platform == 'win32':
-    platform = 'windows'
-  elif sys.platform == 'darwin':
-    platform = 'darwin'
-  else:
-    assert sys.platform.startswith('linux')
-    platform = 'linux'
-  asan_rt_lib_src_dir = os.path.join(COMPILER_RT_BUILD_DIR, 'lib', 'clang',
-                                     VERSION, 'lib', platform)
-  asan_rt_lib_dst_dir = os.path.join(LLVM_BUILD_DIR, 'lib', 'clang',
-                                     VERSION, 'lib', platform)
-  CopyDirectoryContents(asan_rt_lib_src_dir, asan_rt_lib_dst_dir,
-                        r'^.*-i386\.lib$')
-  CopyDirectoryContents(asan_rt_lib_src_dir, asan_rt_lib_dst_dir,
-                        r'^.*-i386\.dll$')
-
-  CopyFile(os.path.join(asan_rt_lib_src_dir, '..', '..', 'asan_blacklist.txt'),
-           os.path.join(asan_rt_lib_dst_dir, '..', '..'))
-
-  if sys.platform == 'win32':
-    # Make an extra copy of the sanitizer headers, to be put on the include path
-    # of the fallback compiler.
-    sanitizer_include_dir = os.path.join(LLVM_BUILD_DIR, 'lib', 'clang',
-                                         VERSION, 'include', 'sanitizer')
-    aux_sanitizer_include_dir = os.path.join(LLVM_BUILD_DIR, 'lib', 'clang',
-                                             VERSION, 'include_sanitizer',
-                                             'sanitizer')
-    if not os.path.exists(aux_sanitizer_include_dir):
-      os.makedirs(aux_sanitizer_include_dir)
-    for _, _, files in os.walk(sanitizer_include_dir):
-      for f in files:
-        CopyFile(os.path.join(sanitizer_include_dir, f),
-                 aux_sanitizer_include_dir)
-
-  # Run tests.
-  if args.run_tests or use_head_revision:
-    os.chdir(LLVM_BUILD_DIR)
-    RunCommand(GetVSVersion().SetupScript('x64') +
-               ['&&', 'ninja', 'cr-check-all'])
-  if args.run_tests:
-    os.chdir(LLVM_BUILD_DIR)
-    RunCommand(GetVSVersion().SetupScript('x64') +
-               ['&&', 'ninja', 'check-all'])
-
-  WriteStampFile(PACKAGE_VERSION)
-  print 'Clang update was successful.'
-  return 0
-
-
-def main():
-  if not sys.platform in ['win32', 'cygwin']:
-    # For non-Windows, fall back to update.sh.
-    # TODO(hans): Make update.py replace update.sh completely.
-
-    # This script is called by gclient. gclient opens its hooks subprocesses
-    # with (stdout=subprocess.PIPE, stderr=subprocess.STDOUT) and then does
-    # custom output processing that breaks printing '\r' characters for
-    # single-line updating status messages as printed by curl and wget.
-    # Work around this by setting stderr of the update.sh process to stdin (!):
-    # gclient doesn't redirect stdin, and while stdin itself is read-only, a
-    # dup()ed sys.stdin is writable, try
-    #   fd2 = os.dup(sys.stdin.fileno()); os.write(fd2, 'hi')
-    # TODO: Fix gclient instead, http://crbug.com/95350
-    if '--no-stdin-hack' in sys.argv:
-      sys.argv.remove('--no-stdin-hack')
-      stderr = None
-    else:
-      try:
-        stderr = os.fdopen(os.dup(sys.stdin.fileno()))
-      except:
-        stderr = sys.stderr
-    return subprocess.call(
-        [os.path.join(os.path.dirname(__file__), 'update.sh')] + sys.argv[1:],
-        stderr=stderr)
-
-  parser = argparse.ArgumentParser(description='Build Clang.')
-  parser.add_argument('--bootstrap', action='store_true',
-                      help='first build clang with CC, then with itself.')
-  parser.add_argument('--if-needed', action='store_true',
-                      help="run only if the script thinks clang is needed")
-  parser.add_argument('--force-local-build', action='store_true',
-                      help="don't try to download prebuild binaries")
-  parser.add_argument('--gcc-toolchain', help='set the version for which gcc '
-                      'version be used for building; --gcc-toolchain=/opt/foo '
-                      'picks /opt/foo/bin/gcc')
-  parser.add_argument('--print-revision', action='store_true',
-                      help='print current clang revision and exit.')
-  parser.add_argument('--print-clang-version', action='store_true',
-                      help='print current clang version (e.g. x.y.z) and exit.')
-  parser.add_argument('--run-tests', action='store_true',
-                      help='run tests after building; only for local builds')
-  parser.add_argument('--tools', nargs='*',
-                      help='select which chrome tools to build',
-                      default=['plugins', 'blink_gc_plugin'])
-  parser.add_argument('--without-patches', action='store_false',
-                      help="don't apply patches (default)", dest='with_patches',
-                      default=True)
-
-  # For now, these flags are only used for the non-Windows flow, but argparser
-  # gets mad if it sees a flag it doesn't recognize.
-  parser.add_argument('--no-stdin-hack', action='store_true')
-
-  args = parser.parse_args()
-
-  if args.if_needed:
-    is_clang_required = False
-    # clang is always used on Mac and Linux.
-    if sys.platform == 'darwin' or sys.platform.startswith('linux'):
-      is_clang_required = True
-    # clang requested via $GYP_DEFINES.
-    if re.search(r'\b(clang|asan|lsan|msan|tsan)=1',
-                 os.environ.get('GYP_DEFINES', '')):
-      is_clang_required = True
-    # clang previously downloaded, keep it up-to-date.
-    # If you don't want this, delete third_party/llvm-build on your machine.
-    if os.path.isdir(LLVM_BUILD_DIR):
-      is_clang_required = True
-    if not is_clang_required:
-      return 0
-    if re.search(r'\b(make_clang_dir)=', os.environ.get('GYP_DEFINES', '')):
-      print 'Skipping Clang update (make_clang_dir= was set in GYP_DEFINES).'
-      return 0
-
-  global LLVM_WIN_REVISION, PACKAGE_VERSION
-  if args.print_revision:
-    if use_head_revision:
-      print GetSvnRevision(LLVM_DIR)
-    else:
-      print PACKAGE_VERSION
-    return 0
-
-  if args.print_clang_version:
-    sys.stdout.write(VERSION)
-    return 0
-
-  # Don't buffer stdout, so that print statements are immediately flushed.
-  # Do this only after --print-revision has been handled, else we'll get
-  # an error message when this script is run from gn for some reason.
-  sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)
-
-  if use_head_revision:
-    # Use a real revision number rather than HEAD to make sure that the stamp
-    # file logic works.
-    LLVM_WIN_REVISION = GetSvnRevision(LLVM_REPO_URL)
-    PACKAGE_VERSION = LLVM_WIN_REVISION + '-0'
-
-    args.force_local_build = True
-    # Skip local patches when using HEAD: they probably don't apply anymore.
-    args.with_patches = False
-
-  return UpdateClang(args)
-
-
-if __name__ == '__main__':
-  sys.exit(main())