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"""
This file contains functions to extract gem5 runtime information.
"""

from m5.defines import buildEnv
from m5.util import warn

from .isas import ISA, get_isa_from_str, get_isas_str_set
from .coherence_protocol import CoherenceProtocol
from typing import Set

def get_supported_isas() -> Set[ISA]:
    """
    Returns the set of all the ISAs compiled into the current binary.
    """
    supported_isas = set()

    if "TARGET_ISA" in buildEnv.keys():
        supported_isas.add(get_isa_from_str(buildEnv["TARGET_ISA"]))

    for key in get_isas_str_set():
        if f"USE_{key.upper()}_ISA" in buildEnv:
            supported_isas.add(get_isa_from_str(key))

    return supported_isas


def get_runtime_isa() -> ISA:
    """
    Returns a single target ISA at runtime.

    This determined via the "TARGET_ISA" parameter, which is set at
    compilation. If not set, but only one ISA is compiled, we assume it's the
    one ISA. If neither the "TARGET_ISA" parameter is set and there are
    multiple ISA targets, an exception is thrown.

    **WARNING**: This function is deprecated and may be removed in future
    versions of gem5. This function should not be relied upon to run gem5
    simulations.

    :returns: The target ISA.
    """

    warn("The `get_runtime_isa` function is deprecated. Please migrate away "
         "from using this function.")

    if "TARGET_ISA" in buildEnv.keys():
        return get_isa_from_str(buildEnv["TARGET_ISA"])

    supported_isas = get_supported_isas()

    if len(supported_isas) == 1:
        return next(iter(supported_isas))

    raise Exception("Cannot determine the the runtime ISA. Either the "
                    "'TARGET_ISA' parameter must be set or the binary only "
                    "compiled to one ISA.")

def get_runtime_coherence_protocol() -> CoherenceProtocol:
    """Gets the cache coherence protocol.
    This can be inferred at runtime.

    :returns: The cache coherence protocol.
    """
    protocol_map = {
        "mi_example": CoherenceProtocol.MI_EXAMPLE,
        "moesi_hammer": CoherenceProtocol.ARM_MOESI_HAMMER,
        "garnet_standalone": CoherenceProtocol.GARNET_STANDALONE,
        "moesi_cmp_token": CoherenceProtocol.MOESI_CMP_TOKEN,
        "mesi_two_level": CoherenceProtocol.MESI_TWO_LEVEL,
        "moesi_amd_base": CoherenceProtocol.MOESI_AMD_BASE,
        "mesi_three_level_htm": CoherenceProtocol.MESI_THREE_LEVEL_HTM,
        "mesi_three_level": CoherenceProtocol.MESI_THREE_LEVEL,
        "gpu_viper": CoherenceProtocol.GPU_VIPER,
        "chi": CoherenceProtocol.CHI,
    }

    protocol_str = str(buildEnv["PROTOCOL"]).lower()
    if protocol_str not in protocol_map.keys():
        raise NotImplementedError(
            "Protocol '" + buildEnv["PROTOCOL"] + "' not recognized."
        )

    return protocol_map[protocol_str]