Python/ceval.c (part 10)

Source:

cpython 3.14 @ ab2d84fe1023/Python/ceval.c

This annotation covers function call specializations and the function/closure creation instructions. See python_ceval9_detail for subscript and binary operator specializations.

Map

Lines	Symbol	Role
1-100	`CALL_PY_EXACT_ARGS`	Call a Python function with exactly the right number of args
101-200	`CALL_PY_WITH_DEFAULTS`	Call with fewer args, filling defaults from `co_defaults`
201-300	`CALL_BUILTIN_O`	Call a C function with one positional argument
301-400	`CALL_BUILTIN_FAST`	Call a C METH_FASTCALL function without a tuple
401-500	`CALL_BUILTIN_FAST_WITH_KEYWORDS`	METH_FASTCALL with keywords
501-600	`COPY_FREE_VARS`	Copy free variable cells from enclosing scope into the frame
601-700	`MAKE_FUNCTION`	Create a function object with defaults and annotations
701-900	`RESUME` / `RETURN_VALUE`	Frame entry guard; return value to caller

Reading

`CALL_PY_EXACT_ARGS`

// CPython: Python/ceval.c:4280 CALL_PY_EXACT_ARGS
inst(CALL_PY_EXACT_ARGS, (unused/1, unused/2, callable, self_or_null, args[oparg] -- res)) {
    DEOPT_IF(!PyFunction_Check(callable), CALL);
    PyFunctionObject *func = (PyFunctionObject *)callable;
    PyCodeObject *code = (PyCodeObject *)func->func_code;
    DEOPT_IF(func->func_defaults != NULL, CALL);       /* has defaults */
    DEOPT_IF(code->co_argcount != oparg + (self_or_null != NULL), CALL);
    /* Push a new frame directly without going through _PyEval_EvalFrameDefault */
    _PyInterpreterFrame *new_frame = _PyFrame_PushUnchecked(tstate, func, oparg);
    ...
    DISPATCH_INLINED(new_frame);
}

DISPATCH_INLINED switches to the new frame without a recursive C call. This is the "inline call" optimization in 3.11+.

`CALL_BUILTIN_O`

// CPython: Python/ceval.c:4400 CALL_BUILTIN_O
inst(CALL_BUILTIN_O, (unused/1, unused/2, callable, self_or_null, args[oparg] -- res)) {
    DEOPT_IF(oparg != 1, CALL);
    DEOPT_IF(!PyCFunction_CheckExact(callable), CALL);
    PyCFunctionObject *cfunc = (PyCFunctionObject *)callable;
    DEOPT_IF(PyCFunction_GET_FLAGS(cfunc) != METH_O, CALL);
    /* Call directly: no tuple creation, no kwargs */
    res = cfunc->vectorcallfunc(callable, &args[0], 1, NULL);
    ...
}

len([1,2,3]) specializes to CALL_BUILTIN_O since len is METH_O (exactly one argument).

`COPY_FREE_VARS`

// CPython: Python/ceval.c:4700 COPY_FREE_VARS
inst(COPY_FREE_VARS, (-- )) {
    /* oparg: number of free variables to copy.
       Free variables come from the enclosing frame's cell array.
       They are copied into the new frame's localsplus[co_nlocals:] slots. */
    PyCodeObject *co = frame->f_code;
    _PyInterpreterFrame *outer = frame->previous;
    for (int i = 0; i < oparg; ++i) {
        PyObject *o = PyTuple_GET_ITEM(frame->f_func->func_closure, i);
        frame->localsplus[co->co_nlocals + i] = Py_NewRef(o);
    }
}

`MAKE_FUNCTION`

// CPython: Python/ceval.c:4780 MAKE_FUNCTION
inst(MAKE_FUNCTION, (codeobj -- func)) {
    /* Create a PyFunctionObject wrapping codeobj.
       Flags (oparg bits) indicate which of:
         0x01: default arguments tuple
         0x02: keyword-only default dict
         0x04: annotations dict
         0x08: closure (tuple of cells)
       are on the stack below codeobj. */
    PyFunctionObject *f = _PyFunction_FromCodeObject(codeobj, globals);
    if (oparg & 0x08) f->func_closure = POP();
    if (oparg & 0x04) f->func_annotations = POP();
    if (oparg & 0x02) f->func_kwdefaults = POP();
    if (oparg & 0x01) f->func_defaults = POP();
    func = (PyObject *)f;
}

gopy notes

CALL_PY_EXACT_ARGS inline dispatch is in vm/eval_call.go:InlineCall. CALL_BUILTIN_O calls vm.CallBuiltinO. COPY_FREE_VARS copies from frame.Func.Closure into frame.Locals[co.NLocals:]. MAKE_FUNCTION is in vm/eval_gen.go:OpMakeFunction.

Map​

Reading​

CALL_PY_EXACT_ARGS​

CALL_BUILTIN_O​

COPY_FREE_VARS​

MAKE_FUNCTION​

gopy notes​

Map