amaranth/nmigen/tracer.py

import inspect
from opcode import opname


__all__ = ["NameNotFound", "get_var_name"]


class NameNotFound(Exception):
    pass


def get_var_name(depth=2):
    frame = inspect.currentframe()
    for _ in range(depth):
        frame = frame.f_back

    code = frame.f_code
    call_index = frame.f_lasti
    call_opc   = opname[code.co_code[call_index]]
    if call_opc not in ("CALL_FUNCTION", "CALL_FUNCTION_KW", "CALL_FUNCTION_EX", "CALL_METHOD"):
        return None

    index = call_index + 2
    while True:
        opc = opname[code.co_code[index]]
        if opc in ("STORE_NAME", "STORE_ATTR"):
            name_index = int(code.co_code[index + 1])
            return code.co_names[name_index]
        elif opc == "STORE_FAST":
            name_index = int(code.co_code[index + 1])
            return code.co_varnames[name_index]
        elif opc == "STORE_DEREF":
            name_index = int(code.co_code[index + 1])
            return code.co_cellvars[name_index]
        elif opc in ("LOAD_GLOBAL", "LOAD_ATTR", "LOAD_FAST", "LOAD_DEREF",
                     "DUP_TOP", "BUILD_LIST"):
            index += 2
        else:
            raise NameNotFound