Function funcnamefromcode

3rd/lua-5.4.3/src/ldebug.c:593–637

** Try to find a name for a function based on the code that called it. ** (Only works when function was called by a Lua function.) ** Returns what the name is (e.g., "for iterator", "method", ** "metamethod") and sets '*name' to point to the name. */

** "metamethod") and sets '*name' to point to the name.
*/
static const char *funcnamefromcode (lua_State *L, CallInfo *ci,
                                     const char **name) {
  TMS tm = (TMS)0;  /* (initial value avoids warnings) */
  const Proto *p = ci_func(ci)->p;  /* calling function */
  int pc = currentpc(ci);  /* calling instruction index */
  Instruction i = p->code[pc];  /* calling instruction */
  if (ci->callstatus & CIST_HOOKED) {  /* was it called inside a hook? */
    *name = "?";
    return "hook";
  }
  switch (GET_OPCODE(i)) {
    case OP_CALL:
    case OP_TAILCALL:
      return getobjname(p, pc, GETARG_A(i), name);  /* get function name */
    case OP_TFORCALL: {  /* for iterator */
      *name = "for iterator";
       return "for iterator";
    }
    /* other instructions can do calls through metamethods */
    case OP_SELF: case OP_GETTABUP: case OP_GETTABLE:
    case OP_GETI: case OP_GETFIELD:
      tm = TM_INDEX;
      break;
    case OP_SETTABUP: case OP_SETTABLE: case OP_SETI: case OP_SETFIELD:
      tm = TM_NEWINDEX;
      break;
    case OP_MMBIN: case OP_MMBINI: case OP_MMBINK: {
      tm = cast(TMS, GETARG_C(i));
      break;
    }
    case OP_UNM: tm = TM_UNM; break;
    case OP_BNOT: tm = TM_BNOT; break;
    case OP_LEN: tm = TM_LEN; break;
    case OP_CONCAT: tm = TM_CONCAT; break;
    case OP_EQ: tm = TM_EQ; break;
    /* no cases for OP_EQI and OP_EQK, as they don't call metamethods */
    case OP_LT: case OP_LTI: case OP_GTI: tm = TM_LT; break;
    case OP_LE: case OP_LEI: case OP_GEI: tm = TM_LE; break;
    case OP_CLOSE: case OP_RETURN: tm = TM_CLOSE; break;
    default:
      return NULL;  /* cannot find a reasonable name */
  }
  *name = getstr(G(L)->tmname[tm]) + 2;
  return "metamethod";
}

/* }====================================================== */