#!/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()