Python/ceval.c (part 64)

Source:

cpython 3.14 @ ab2d84fe1023/Python/ceval.c ↗

This annotation covers CALL specializations. See python_ceval63_detail for GET_ITER, FOR_ITER, GET_AITER, and GET_ANEXT.

Map

Lines	Symbol	Role
1-80	CALL baseline	Generic call dispatch
81-160	CALL_PY_EXACT_ARGS	Fast path for Python function with exact arg count
161-240	CALL_PY_WITH_DEFAULTS	Python function with defaults
241-320	CALL_BUILTIN_CLASS	list(iter), dict(), type(x)
321-500	CALL_NO_KW_TYPE_1	type(x) single-argument fast path

Reading

CALL_PY_EXACT_ARGS

// CPython: Python/ceval.c:3060 CALL_PY_EXACT_ARGS
inst(CALL_PY_EXACT_ARGS, (unused/1, unused/2, callable, self_or_null, args[oparg] -- unused)) {
    DEOPT_IF(!PyFunction_Check(callable), CALL);
    PyFunctionObject *func = (PyFunctionObject *)callable;
    DEOPT_IF(func->func_version != read_u32(next_instr[-2].cache), CALL);
    PyCodeObject *code = (PyCodeObject *)func->func_code;
    DEOPT_IF(code->co_argcount != oparg + (self_or_null != NULL), CALL);
    DEOPT_IF(!_PyThreadState_HasStackSpace(tstate, code->co_framesize), CALL);
    /* Push frame and dispatch */
    _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func, oparg + (self_or_null != NULL));
    ...
    DISPATCH_INLINED(new_frame);
}

CALL_PY_EXACT_ARGS handles f(a, b, c) where f is a Python function expecting exactly oparg args. The func_version check ensures the function hasn't been modified. DISPATCH_INLINED enters the new frame directly without going through the main dispatch loop.

CALL_PY_WITH_DEFAULTS

// CPython: Python/ceval.c:3120 CALL_PY_WITH_DEFAULTS
inst(CALL_PY_WITH_DEFAULTS, (unused/1, unused/2, callable, self_or_null, args[oparg] -- unused)) {
    DEOPT_IF(!PyFunction_Check(callable), CALL);
    PyFunctionObject *func = (PyFunctionObject *)callable;
    DEOPT_IF(func->func_version != read_u32(next_instr[-2].cache), CALL);
    PyCodeObject *code = (PyCodeObject *)func->func_code;
    int argcount = oparg + (self_or_null != NULL);
    DEOPT_IF(argcount > code->co_argcount, CALL);
    int defcount = func->func_defaults == NULL ? 0 : (int)PyTuple_GET_SIZE(func->func_defaults);
    DEOPT_IF(argcount < code->co_argcount - defcount, CALL);
    /* Fill in defaults */
    ...
    DISPATCH_INLINED(new_frame);
}

CALL_PY_WITH_DEFAULTS handles calls where some positional arguments use defaults from func.__defaults__. The specialization verifies the argument count is in range [co_argcount - defcount, co_argcount].

CALL_NO_KW_TYPE_1

// CPython: Python/ceval.c:3220 CALL_NO_KW_TYPE_1
inst(CALL_NO_KW_TYPE_1, (unused/1, unused/2, callable, null, arg -- res)) {
    DEOPT_IF(null != NULL, CALL);
    DEOPT_IF(callable != (PyObject *)&PyType_Type, CALL);
    DEOPT_IF(Py_TYPE(arg)->tp_doc == NULL, CALL);
    res = Py_NewRef(Py_TYPE(arg));
    Py_DECREF(arg);
    Py_DECREF(callable);
}

type(x) with a single argument returns x's type. This specialization avoids the full type.__call__ machinery by directly returning Py_TYPE(arg). The check tp_doc == NULL guards against pathological types with unusual tp_type behavior.

gopy notes

CALL_PY_EXACT_ARGS is in vm/eval_call.go. It creates a new vm.Frame directly and enters it via evalInlined. CALL_PY_WITH_DEFAULTS fills missing args from objects.Function.Defaults. CALL_NO_KW_TYPE_1 returns objects.TypeOf(arg) directly.