#!/usr/bin/env python
# Copyright 2018 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Runs clang's "modern objective-c" rewriter on chrome code.
Does the same as Xcode's Edit->Convert->To Modern Objective-C Syntax.
Note that this just runs compile commands and doesn't look at build
dependencies, i.e. it doesn't make sure generated headers exist. It also
requires reclient to be disabled. Suggested workflow: Build the target you want
to convert locally with reclient to create generated headers, then disable
reclient, re-run gn, and then run this script.
Since Chrome's clang disables the rewriter, to run this you will need to
build ToT clang with `-DCLANG_ENABLE_ARCMT` and (temporarily) add the following
to your Chromium build args:
clang_base_path = /path/to/clang
clang_use_chrome_plugins = false
"""
from __future__ import print_function
import argparse
import glob
import json
import math
import os
import shlex
import subprocess
import sys
def main():
# As far as I can tell, clang's ObjC rewriter can't do in-place rewriting
# (the ARC rewriter can). libclang exposes functions for parsing the remap
# file, but doing that manually in python seems a lot easier.
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument('builddir', help='build directory, e.g. out/gn')
parser.add_argument('substr', default='', nargs='?',
help='source dir part, eg chrome/browser/ui/cocoa')
args = parser.parse_args()
rewrite_dir = os.path.abspath(
os.path.join(args.builddir, 'rewrite_modern_objc'))
try:
os.mkdir(rewrite_dir)
except OSError:
pass
remap_file = os.path.join(rewrite_dir, 'remap')
try:
# Remove remap files from prior runs.
os.remove(remap_file)
except OSError:
pass
# The basic idea is to call clang's objcmt rewriter for each source file.
# The rewriter writes a "remap" file containing N times 3 lines:
# Name of an original source file, the original file's timestamp
# at rewriting time, and the name of a temp file containing the rewritten
# contents.
# The rewriter gets confused if several instances run in parallel. We could
# be fancy and have num_cpus rewrite dirs and combine their contents in the
# end, but for now just run the rewrites serially.
# First, ask ninja for the compile commands of all .m and .mm files.
compdb = subprocess.check_output(
['ninja', '-C', args.builddir, '-t', 'compdb', 'objc', 'objcxx'])
for cmd in json.loads(compdb):
objc_file = cmd['file']
if args.substr not in objc_file:
continue
clang_cmd = cmd['command']
had_error = False
if 'rewrapper' in clang_cmd:
print('need builddir with use_remoteexec not set', file=sys.stderr)
had_error = True
if 'jumbo' in clang_cmd:
print('need builddir with use_jumbo_build not set', file=sys.stderr)
had_error = True
if 'precompile.h-m' in clang_cmd:
print(
'need builddir with enable_precompiled_headers=false',
file=sys.stderr)
had_error = True
if had_error:
sys.exit(1)
# Ninja creates the directory containing the build output, but we
# don't run ninja, so we need to do that ourselves.
split_cmd = shlex.split(clang_cmd)
o_index = split_cmd.index('-o')
assert o_index != -1
try:
os.makedirs(os.path.dirname(split_cmd[o_index + 1]))
except OSError:
pass
# Add flags to tell clang to do the rewriting.
# Passing "-ccc-objcmt-migrate dir" doesn't give us control over each
# individual setting, so use the Xclang flags. The individual flags are at
# http://llvm-cs.pcc.me.uk/tools/clang/include/clang/Driver/Options.td#291
# Note that -objcmt-migrate-all maps to ObjCMT_MigrateDecls in
# http://llvm-cs.pcc.me.uk/tools/clang/lib/Frontend/CompilerInvocation.cpp#1479
# which is not quite all the options:
# http://llvm-cs.pcc.me.uk/tools/clang/include/clang/Frontend/FrontendOptions.h#248
flags = ['-Xclang', '-mt-migrate-directory', '-Xclang', rewrite_dir]
flags += ['-Xclang', '-objcmt-migrate-subscripting' ]
flags += ['-Xclang', '-objcmt-migrate-literals' ]
#flags += ['-Xclang', '-objcmt-returns-innerpointer-property'] # buggy
#flags += ['-Xclang', '-objcmt-migrate-property-dot-syntax'] # do not want
# objcmt-migrate-all is the same as the flags following it here (it does
# not include the flags listed above it).
# Probably don't want ns-nonatomic-iosonly (or atomic-property), so we
# can't use migrate-alll which includes that, and have to manually set the
# bits of migrate-all we do want.
#flags += ['-Xclang', '-objcmt-migrate-all']
#flags += ['-Xclang', '-objcmt-migrate-property'] # not sure if want
flags += ['-Xclang', '-objcmt-migrate-annotation']
flags += ['-Xclang', '-objcmt-migrate-instancetype']
flags += ['-Xclang', '-objcmt-migrate-ns-macros']
#flags += ['-Xclang', '-objcmt-migrate-protocol-conformance'] # buggy
#flags += ['-Xclang', '-objcmt-atomic-property'] # not sure if want
#flags += ['-Xclang', '-objcmt-ns-nonatomic-iosonly'] # not sure if want
# Want, but needs careful manual review, and doesn't find everything:
#flags += ['-Xclang', '-objcmt-migrate-designated-init']
clang_cmd += ' ' + ' '.join(flags)
print(objc_file)
subprocess.check_call(clang_cmd, shell=True, cwd=cmd['directory'])
if not os.path.exists(remap_file):
print('no changes')
return
# Done with rewriting. Now the read the above-described 'remap' file and
# copy modified files over the originals.
remap = open(remap_file).readlines()
for i in range(0, len(remap), 3):
infile, mtime, outfile = map(str.strip, remap[i:i+3])
if args.substr not in infile:
# Ignore rewritten header files not containing args.substr too.
continue
if math.trunc(os.path.getmtime(infile)) != int(mtime):
print('%s was modified since rewriting; exiting' % infile)
sys.exit(1)
os.rename(outfile, infile) # Copy rewritten file over.
print('all done. commit, run `git cl format`, commit again, and upload!')
if __name__ == '__main__':
main()
Codebase Browser
chromium