Python/ceval.c (part 26)

Source:

cpython 3.14 @ ab2d84fe1023/Python/ceval.c ↗

This annotation covers function construction and dynamic call opcodes. See python_ceval25_detail for unpacking and f-string opcodes.

Map

Lines	Symbol	Role
1-80	CALL_FUNCTION_EX	f(*args, **kwargs) — unpack iterables and mappings
81-180	KW_NAMES	Annotate the next CALL with keyword argument names
181-280	MAKE_FUNCTION	Create a function object from a code object
281-380	SET_FUNCTION_ATTRIBUTE	Attach defaults, annotations, closure to function
381-500	CALL_INTRINSIC_1	Built-in intrinsic operations (import star, list-to-tuple, etc.)

Reading

CALL_FUNCTION_EX

// CPython: Python/ceval.c:5020 CALL_FUNCTION_EX
inst(CALL_FUNCTION_EX, (func, unused, callargs, kwargs --  result)) {
    /* f(*args, **kwargs): unpack callargs and kwargs */
    if (!PyTuple_CheckExact(callargs)) {
        PyObject *tmp = PySequence_Tuple(callargs);
        Py_DECREF(callargs);
        callargs = tmp;
    }
    if (kwargs) {
        if (!PyDict_CheckExact(kwargs)) {
            PyObject *tmp = PyDict_Copy(kwargs);
            Py_DECREF(kwargs);
            kwargs = tmp;
        }
    }
    result = PyObject_Call(func, callargs, kwargs);
}

f(*args, **kwargs) compiles to CALL_FUNCTION_EX. If args is not a tuple (e.g., a generator), it is materialized first. kwargs must be a dict. Both copies are made to avoid aliasing issues if the function modifies them.

MAKE_FUNCTION

// CPython: Python/ceval.c:5180 MAKE_FUNCTION
inst(MAKE_FUNCTION, (codeobj -- func)) {
    PyFunctionObject *function = (PyFunctionObject *)PyFunction_New(codeobj, GLOBALS());
    function->func_name = codeobj->co_name;
    /* func_qualname is set by SET_FUNCTION_ATTRIBUTE */
    func = (PyObject *)function;
}

def f(): ... at module level emits LOAD_CONST <code>, MAKE_FUNCTION. The function object is created here; defaults and annotations are set by subsequent SET_FUNCTION_ATTRIBUTE opcodes. This separation allows the compiler to emit defaults before MAKE_FUNCTION.

SET_FUNCTION_ATTRIBUTE

// CPython: Python/ceval.c:5220 SET_FUNCTION_ATTRIBUTE
inst(SET_FUNCTION_ATTRIBUTE, (attr, func -- func)) {
    /* oparg: which attribute to set
       0x01 = __defaults__    (positional defaults tuple)
       0x02 = __kwdefaults__  (keyword-only defaults dict)
       0x04 = __annotations__
       0x08 = __closure__
       0x10 = __qualname__    */
    switch (oparg) {
    case 0x01: ((PyFunctionObject *)func)->func_defaults = Py_NewRef(attr); break;
    case 0x02: ((PyFunctionObject *)func)->func_kwdefaults = Py_NewRef(attr); break;
    case 0x04: ((PyFunctionObject *)func)->func_annotations = Py_NewRef(attr); break;
    case 0x08: ((PyFunctionObject *)func)->func_closure = Py_NewRef(attr); break;
    case 0x10: ((PyFunctionObject *)func)->func_qualname = Py_NewRef(attr); break;
    }
}

Multiple SET_FUNCTION_ATTRIBUTE opcodes may follow a single MAKE_FUNCTION. Each one pops the attribute value and sets the corresponding slot. Unused attributes are not emitted, keeping the bytecode compact.

gopy notes

CALL_FUNCTION_EX is vm.CallFunctionEx in vm/eval_call.go. MAKE_FUNCTION is vm.MakeFunction, creating objects.FunctionObject. SET_FUNCTION_ATTRIBUTE is vm.SetFunctionAttribute. CALL_INTRINSIC_1 dispatches via vm.Intrinsic1Table.