author Andrew McCreight <continuation@gmail.com>
Mon, 22 Apr 2019 16:34:51 +0000
changeset 470376 3073770e06f157040f4c64951b7e8425e1ad7bbe
parent 455286 8dcbc414dda673564951f3a28099643f3a8d1ed6
permissions -rw-r--r--
Bug 1535403 - Take indirection into account for the CC optimizations for the outer window wrapper. r=peterv Most wrapper cached C++ objects are held alive by their wrapper. The cycle collector takes advantage of this in many classes and ignores the C++ object if the wrapper is marked black. However, this is not true for the outer window's wrapper. Instead, the outer window's wrapper keeps the inner window alive. The inner window usually keeps its outer window alive, but not after it has been unlinked. For reasons I do not yet understand, the outer window's wrapper can be kept alive after the inner window it is a proxy for is unlinked. This patch fixes the cycle collector optimization for the outer window by only applying it if the outer window still has a weak reference to the inner window, which it will until the inner no longer holds the outer alive. This in turn fixes, or at least helps fix, window leaks seen intermittently when the lifetime of outer windows and docshells are tied together. The code comment is based on a review comment by peterv. Differential Revision: https://phabricator.services.mozilla.com/D27981

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

from __future__ import absolute_import, print_function
import json
import os
import shlex
import subprocess
import sys

old_bytecode = sys.dont_write_bytecode
sys.dont_write_bytecode = True

path = os.path.abspath(os.path.join(os.path.dirname(__file__), 'mach'))

# If mach is not here, we're on the objdir go to the srcdir.
if not os.path.exists(path):
    with open(os.path.join(os.path.dirname(__file__), 'mozinfo.json')) as info:
        config = json.loads(info.read())
    path = os.path.join(config['topsrcdir'], 'mach')

sys.dont_write_bytecode = old_bytecode

def _is_likely_cpp_header(filename):
    if not filename.endswith('.h'):
        return False

    if filename.endswith('Inlines.h') or filename.endswith('-inl.h'):
        return True

    cpp_file = filename[:-1] + 'cpp'
    return os.path.exists(cpp_file)

def FlagsForFile(filename):
    output = subprocess.check_output([path, 'compileflags', filename])
    output = output.decode('utf-8')

    flag_list = shlex.split(output)

    # This flag is added by Fennec for android build and causes ycmd to fail to parse the file.
    # Removing this flag is a workaround until ycmd starts to handle this flag properly.
    # https://github.com/Valloric/YouCompleteMe/issues/1490
    final_flags = [x for x in flag_list if not x.startswith('-march=armv')]

    if _is_likely_cpp_header(filename):
        final_flags += ["-x", "c++"]

    return {
        'flags': final_flags,
        'do_cache': True

if __name__ == '__main__':