nmigen/tracer.py

   1 import inspect
   2 from opcode import opname
   3
   4
   5 __all__ = ["NameNotFound", "get_var_name"]
   6
   7
   8 class NameNotFound(Exception):
   9     pass
  10
  11
  12 def get_var_name(depth=2):
  13     frame = inspect.currentframe()
  14     for _ in range(depth):
  15         frame = frame.f_back
  16
  17     code = frame.f_code
  18     call_index = frame.f_lasti
  19     call_opc   = opname[code.co_code[call_index]]
  20     if call_opc not in ("CALL_FUNCTION", "CALL_FUNCTION_KW", "CALL_FUNCTION_EX", "CALL_METHOD"):
  21         return None
  22
  23     index = call_index + 2
  24     while True:
  25         opc = opname[code.co_code[index]]
  26         if opc in ("STORE_NAME", "STORE_ATTR"):
  27             name_index = int(code.co_code[index + 1])
  28             return code.co_names[name_index]
  29         elif opc == "STORE_FAST":
  30             name_index = int(code.co_code[index + 1])
  31             return code.co_varnames[name_index]
  32         elif opc == "STORE_DEREF":
  33             name_index = int(code.co_code[index + 1])
  34             return code.co_cellvars[name_index]
  35         elif opc in ("LOAD_GLOBAL", "LOAD_ATTR", "LOAD_FAST", "LOAD_DEREF",
  36                      "DUP_TOP", "BUILD_LIST"):
  37             index += 2
  38         else:
  39             raise NameNotFound