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"""
This file contains extensions of the multiprocessing module to be used with gem5.
Specifically, it contains the code to produce the command line for spawned processes.
Some code inspired by the Python standard library implementation of the
multiprocessing module (i.e., cpython/Lib/multiprocessing/).
"""

import sys
from multiprocessing import spawn, util


def _gem5_args_for_multiprocessing(name):
    from m5 import options

    # Options that are disallowed with multiprocessing
    disallowed = [
        options.build_info,
        options.copyright,
        options.readme,
        options.interactive,
        options.pdb,
        options.verbose,
        options.debug_break,
        options.debug_help,
        options.debug_flags,
        options.debug_start,
        options.debug_end,
        options.debug_ignore,
        options.list_sim_objects,
    ]
    if any(disallowed):
        raise Exception(
            f"Disallowed option for multiprocessing. "
            f"See {__file__} for details."
        )

    # Options not forwarded:
    # --allow-remote-connections, --listener-mode, --dump-config, --json-config
    # --dot-config, --dot-dvfs-config, --debug-file, --remote-gdb-port, -c

    arguments = [
        f"--outdir={options.outdir}/{name}",
        f"--stdout-file={options.stdout_file}",
        f"--stderr-file={options.stderr_file}",
        f"--stats-file={options.stats_file}",
    ]
    if options.redirect_stdout:
        arguments.append("--redirect-stdout")
    if options.redirect_stderr:
        arguments.append("--redirect-stderr")
    if options.silent_redirect:
        arguments.append("--silent-redirect")
    if options.path:
        arguments.append(f"--path={':'.join(options.path)}")
    if options.quiet:
        arguments.append("--quiet")

    return arguments


def get_command_line(name, **kwds):
    """
    Returns prefix of command line used for spawning a child process
    """
    if getattr(sys, "frozen", False):
        return [sys.executable, "--multiprocessing-fork"] + [
            "%s=%r" % item for item in kwds.items()
        ]
    else:
        prog = "from multiprocessing.spawn import spawn_main; spawn_main(%s)"
        prog %= ", ".join("%s=%r" % item for item in kwds.items())
        opts = util._args_from_interpreter_flags()
        opts.extend(_gem5_args_for_multiprocessing(name))
        exe = spawn.get_executable()
        return [exe] + opts + ["-c", prog, "--multiprocessing-fork"]