xref: /build/toolchain/wrapper_utils.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2016 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.

"""Helper functions for gcc_toolchain.gni wrappers."""

import gzip
import os
import subprocess
import shutil
import threading

_BAT_PREFIX = 'cmd /c call '


def _gzip_then_delete(src_path, dest_path):
    """ Results for ohos map file with GCC on a z620:
    Uncompressed: 207MB
    gzip -9: 16.4MB, takes 8.7 seconds.
    gzip -1: 21.8MB, takes 2.0 seconds.
    Piping directly from the linker via -print-map (or via -Map with a fifo)
    adds a whopping 30-45 seconds!
    """
    with open(src_path, 'rb') as f_in, gzip.GzipFile(dest_path,
                                                     'wb',
                                                     1) as f_out:
        shutil.copyfileobj(f_in, f_out)
    os.unlink(src_path)


def command_to_run(command):
    """Generates commands compatible with Windows.

    When running on a Windows host and using a toolchain whose tools are
    actually wrapper scripts (i.e. .bat files on Windows) rather than binary
    executables, the |command| to run has to be prefixed with this magic.
    The GN toolchain definitions take care of that for when GN/Ninja is
    running the tool directly.  When that command is passed in to this
    script, it appears as a unitary string but needs to be split up so that
    just 'cmd' is the actual command given to Python's subprocess module.

    Args:
      command: List containing the UNIX style |command|.

    Returns:
      A list containing the Windows version of the |command|.
    """
    if command[0].startswith(_BAT_PREFIX):
        command = command[0].split(None, 3) + command[1:]
    return command


def run_link_with_optional_map_file(command, env=None, map_file=None):
    """Runs the given command, adding in -Wl,-Map when |map_file| is given.

    Also takes care of gzipping when |map_file| ends with .gz.

    Args:
      command: List of arguments comprising the command.
      env: Environment variables.
      map_file: Path to output map_file.

    Returns:
      The exit code of running |command|.
    """
    tmp_map_path = None
    if map_file and map_file.endswith('.gz'):
        tmp_map_path = map_file + '.tmp'
        command.append('-Wl,-Map,' + tmp_map_path)
    elif map_file:
        command.append('-Wl,-Map,' + map_file)

    result = subprocess.call(command, env=env)

    if tmp_map_path and result == 0:
        threading.Thread(
            target=lambda: _gzip_then_delete(tmp_map_path, map_file)).start()
    elif tmp_map_path and os.path.exists(tmp_map_path):
        os.unlink(tmp_map_path)

    return result


def capture_command_stderr(command, env=None):
    """Returns the stderr of a command.

    Args:
      command: A list containing the command and arguments.
      env: Environment variables for the new process.
    """
    child = subprocess.Popen(command, stderr=subprocess.PIPE, env=env)
    _, stderr = child.communicate()
    return child.returncode, stderr