typedef struct {
    PyObject_HEAD
    PyObject *func_code;	/* A code object */
    PyObject *func_globals;	/* A dictionary (other mappings won't do) */
    PyObject *func_defaults;	/* NULL or a tuple */
    PyObject *func_closure;	/* NULL or a tuple of cell objects */
    PyObject *func_doc;		/* The __doc__ attribute, can be anything */
    PyObject *func_name;	/* The __name__ attribute, a string object */
    PyObject *func_dict;	/* The __dict__ attribute, a dict or NULL */
    PyObject *func_weakreflist;	/* List of weak references */
    PyObject *func_module;	/* The __module__ attribute, can be anything */

    /* Invariant:
     *     func_closure contains the bindings for func_code->co_freevars, so
     *     PyTuple_Size(func_closure) == PyCode_GetNumFree(func_code)
     *     (func_closure may be NULL if PyCode_GetNumFree(func_code) == 0).
     */
} PyFunctionObject;

case MAKE_FUNCTION:
			v = POP(); /* code object */
			x = PyFunction_New(v, f->f_globals);
			Py_DECREF(v);
			/* XXX Maybe this should be a separate opcode? */
			if (x != NULL && oparg> 0) {
                // oparg 表示 “具有默认值的参数” 的个数
				v = PyTuple_New(oparg);
				if (v == NULL) {
					Py_DECREF(x);
					x = NULL;
					break;
				}
				while (--oparg>= 0) {
					w = POP();
					PyTuple_SET_ITEM(v, oparg, w);
				}
				err = PyFunction_SetDefaults(x, v);
				Py_DECREF(v);
			}
			PUSH(x);
			break;

case CALL_FUNCTION:
		{
			PyObject **sp;
			PCALL(PCALL_ALL);
			sp = stack_pointer;
#ifdef WITH_TSC
			x = call_function(&sp, oparg, &intr0, &intr1);
#else
			x = call_function(&sp, oparg);
#endif
			stack_pointer = sp;
			PUSH(x); // 函数返回值
			if (x != NULL)
				continue;
			break;
		}

static PyObject *
call_function(PyObject ***pp_stack, int oparg
#ifdef WITH_TSC
		, uint64* pintr0, uint64* pintr1
#endif
		)
{
    // oparg 是 short 类型，高字节表示 nk（实参中关键字参数个数），低字节表示 na（实参中位置参数个数）
	int na = oparg & 0xff;
	int nk = (oparg>>8) & 0xff;
	int n = na + 2 * nk;
	PyObject **pfunc = (*pp_stack) - n - 1;
	PyObject *func = *pfunc;
	PyObject *x, *w;

	/* Always dispatch PyCFunction first, because these are
	   presumed to be the most frequent callable object.
	*/
	if (PyCFunction_Check(func) && nk == 0) {
		int flags = PyCFunction_GET_FLAGS(func);
		PyThreadState *tstate = PyThreadState_GET();

		PCALL(PCALL_CFUNCTION);
		if (flags & (METH_NOARGS | METH_O)) {
			PyCFunction meth = PyCFunction_GET_FUNCTION(func);
			PyObject *self = PyCFunction_GET_SELF(func);
			if (flags & METH_NOARGS && na == 0) {
				C_TRACE(x, (*meth)(self,NULL));
			}
			else if (flags & METH_O && na == 1) {
				PyObject *arg = EXT_POP(*pp_stack);
				C_TRACE(x, (*meth)(self,arg));
				Py_DECREF(arg);
			}
			else {
				err_args(func, flags, na);
				x = NULL;
			}
		}
		else {
			PyObject *callargs;
			callargs = load_args(pp_stack, na);
			READ_TIMESTAMP(*pintr0);
			C_TRACE(x, PyCFunction_Call(func,callargs,NULL));
			READ_TIMESTAMP(*pintr1);
			Py_XDECREF(callargs);
		}
	} else {
		if (PyMethod_Check(func) && PyMethod_GET_SELF(func) != NULL) {
			/* optimize access to bound methods */
			PyObject *self = PyMethod_GET_SELF(func);
			PCALL(PCALL_METHOD);
			PCALL(PCALL_BOUND_METHOD);
			Py_INCREF(self);
			func = PyMethod_GET_FUNCTION(func);
			Py_INCREF(func);
			Py_DECREF(*pfunc);
			*pfunc = self;
			na++;
			n++;
		} else
			Py_INCREF(func);
		READ_TIMESTAMP(*pintr0);
		if (PyFunction_Check(func))
			x = fast_function(func, pp_stack, n, na, nk);
		else
			x = do_call(func, pp_stack, na, nk);
		READ_TIMESTAMP(*pintr1);
		Py_DECREF(func);
	}

	/* Clear the stack of the function object.  Also removes
           the arguments in case they weren't consumed already
           (fast_function() and err_args() leave them on the stack).
	 */
	while ((*pp_stack) > pfunc) {
		w = EXT_POP(*pp_stack);
		Py_DECREF(w);
		PCALL(PCALL_POP);
	}
	return x;
}