GH-100719: Remove redundant gi_code field from generator object.

Include/cpython/genobject.h

@@ -13,8 +13,6 @@ extern "C" {
  and coroutine objects. */
 #define _PyGenObject_HEAD(prefix) \
  PyObject_HEAD \
- /* The code object backing the generator */ \
- PyCodeObject *prefix##_code; \
  /* List of weak reference. */ \
  PyObject *prefix##_weakreflist; \
  /* Name of the generator. */ \
@@ -28,7 +26,7 @@ extern "C" {
  char prefix##_running_async; \
  /* The frame */ \
  int8_t prefix##_frame_state; \
- PyObject *prefix##_iframe[1];
+ PyObject *prefix##_iframe[1]; \
 
 typedef struct {
  /* The gi_ prefix is intended to remind of generator-iterator. */
@@ -46,6 +44,7 @@ PyAPI_FUNC(PyObject *) PyGen_NewWithQualName(PyFrameObject *,
 PyAPI_FUNC(int) _PyGen_SetStopIterationValue(PyObject *);
 PyAPI_FUNC(int) _PyGen_FetchStopIterationValue(PyObject **);
 PyAPI_FUNC(void) _PyGen_Finalize(PyObject *self);
+PyAPI_FUNC(PyCodeObject *) PyGen_GetCode(PyGenObject *gen);
 
 
 /* --- PyCoroObject ------------------------------------------------------- */

Include/internal/pycore_frame.h

@@ -209,7 +209,7 @@ _PyFrame_GetFrameObject(_PyInterpreterFrame *frame)
  * frames like the ones in generators and coroutines.
  */
 void
-_PyFrame_Clear(_PyInterpreterFrame * frame);
+_PyFrame_ClearExceptCode(_PyInterpreterFrame * frame);
 
 int
 _PyFrame_Traverse(_PyInterpreterFrame *frame, visitproc visit, void *arg);

Lib/test/test_capi/test_misc.py

@@ -1213,6 +1213,11 @@ def test_pendingcalls_non_threaded(self):
  self.pendingcalls_submit(l, n)
  self.pendingcalls_wait(l, n)
 
+ def test_gen_get_code(self):
+ def genf(): yield
+ gen = genf()
+ self.assertEqual(_testcapi.gen_get_code(gen), gen.gi_code)
+
 
 class SubinterpreterTest(unittest.TestCase):
 

Lib/test/test_sys.py

@@ -1460,7 +1460,7 @@ def bar(cls):
  check(bar, size('PP'))
  # generator
  def get_gen(): yield 1
- check(get_gen(), size('P2P4P4c7P2ic??2P'))
+ check(get_gen(), size('PP4P4c7P2ic??2P'))
  # iterator
  check(iter('abc'), size('lP'))
  # callable-iterator

Misc/NEWS.d/next/Core and Builtins/2023-01-04-12-49-33.gh-issue-100719.uRPccL.rst

@@ -0,0 +1,3 @@
+Remove gi_code field from generator (and coroutine and async generator)
+objects as it is redundant. The frame already includes a reference to the
+code object.

Modules/_testcapimodule.c

@@ -3076,6 +3076,16 @@ eval_get_func_desc(PyObject *self, PyObject *func)
  return PyUnicode_FromString(PyEval_GetFuncDesc(func));
 }
 
+static PyObject *
+gen_get_code(PyObject *self, PyObject *gen)
+{
+ if (!PyGen_Check(gen)) {
+ PyErr_SetString(PyExc_TypeError, "argument must be a generator object");
+ return NULL;
+ }
+ return (PyObject *)PyGen_GetCode((PyGenObject *)gen);
+}
+
 static PyObject *
 eval_eval_code_ex(PyObject *mod, PyObject *pos_args)
 {
@@ -3657,6 +3667,7 @@ static PyMethodDef TestMethods[] = {
  {"frame_getvarstring", test_frame_getvarstring, METH_VARARGS, NULL},
  {"eval_get_func_name", eval_get_func_name, METH_O, NULL},
  {"eval_get_func_desc", eval_get_func_desc, METH_O, NULL},
+ {"gen_get_code", gen_get_code, METH_O, NULL},
  {"get_feature_macros", get_feature_macros, METH_NOARGS, NULL},
  {"test_code_api", test_code_api, METH_NOARGS, NULL},
  {"settrace_to_record", settrace_to_record, METH_O, NULL},

Objects/genobject.c

@@ -24,6 +24,21 @@ static const char *NON_INIT_CORO_MSG = "can't send non-None value to a "
 static const char *ASYNC_GEN_IGNORED_EXIT_MSG =
  "async generator ignored GeneratorExit";
 
+/* Returns a borrowed reference */
+static inline PyCodeObject *
+_PyGen_GetCode(PyGenObject *gen) {
+ _PyInterpreterFrame *frame = (_PyInterpreterFrame *)(gen->gi_iframe);
+ return frame->f_code;
+}
+
+PyCodeObject *
+PyGen_GetCode(PyGenObject *gen) {
+ assert(PyGen_Check(gen));
+ PyCodeObject *res = _PyGen_GetCode(gen);
+ Py_INCREF(res);
+ return res;
+}
+
 static inline int
 exc_state_traverse(_PyErr_StackItem *exc_state, visitproc visit, void *arg)
 {
@@ -34,7 +49,6 @@ exc_state_traverse(_PyErr_StackItem *exc_state, visitproc visit, void *arg)
 static int
 gen_traverse(PyGenObject *gen, visitproc visit, void *arg)
 {
- Py_VISIT(gen->gi_code);
  Py_VISIT(gen->gi_name);
  Py_VISIT(gen->gi_qualname);
  if (gen->gi_frame_state < FRAME_CLEARED) {
@@ -88,8 +102,8 @@ _PyGen_Finalize(PyObject *self)
 
  /* If `gen` is a coroutine, and if it was never awaited on,
  issue a RuntimeWarning. */
-if (gen->gi_code != NULL &&
- ((PyCodeObject *)gen->gi_code)->co_flags & CO_COROUTINE &&
+assert(_PyGen_GetCode(gen) != NULL);
+if (_PyGen_GetCode(gen)->co_flags & CO_COROUTINE &&
  gen->gi_frame_state == FRAME_CREATED)
  {
  _PyErr_WarnUnawaitedCoroutine((PyObject *)gen);
@@ -137,12 +151,12 @@ gen_dealloc(PyGenObject *gen)
  _PyInterpreterFrame *frame = (_PyInterpreterFrame *)gen->gi_iframe;
  gen->gi_frame_state = FRAME_CLEARED;
  frame->previous = NULL;
-_PyFrame_Clear(frame);
+_PyFrame_ClearExceptCode(frame);
  }
- if (((PyCodeObject *)gen->gi_code)->co_flags & CO_COROUTINE) {
+ if (_PyGen_GetCode(gen)->co_flags & CO_COROUTINE) {
  Py_CLEAR(((PyCoroObject *)gen)->cr_origin_or_finalizer);
  }
-Py_CLEAR(gen->gi_code);
+Py_DECREF(_PyGen_GetCode(gen));
  Py_CLEAR(gen->gi_name);
  Py_CLEAR(gen->gi_qualname);
  _PyErr_ClearExcState(&gen->gi_exc_state);
@@ -332,7 +346,7 @@ _PyGen_yf(PyGenObject *gen)
  /* Return immediately if the frame didn't start yet. SEND
  always come after LOAD_CONST: a code object should not start
  with SEND */
- assert(_PyCode_CODE(gen->gi_code)[0].op.code != SEND);
+ assert(_PyCode_CODE(_PyGen_GetCode(gen))[0].op.code != SEND);
  return NULL;
  }
  _Py_CODEUNIT next = frame->prev_instr[1];
@@ -767,6 +781,21 @@ gen_getframe(PyGenObject *gen, void *Py_UNUSED(ignored))
  return _gen_getframe(gen, "gi_frame");
 }
 
+static PyObject *
+_gen_getcode(PyGenObject *gen, const char *const name)
+{
+ if (PySys_Audit("object.__getattr__", "Os", gen, name) < 0) {
+ return NULL;
+ }
+ return Py_NewRef(_PyGen_GetCode(gen));
+}
+
+static PyObject *
+gen_getcode(PyGenObject *gen, void *Py_UNUSED(ignored))
+{
+ return _gen_getcode(gen, "gi_code");
+}
+
 static PyGetSetDef gen_getsetlist[] = {
  {"__name__", (getter)gen_get_name, (setter)gen_set_name,
  PyDoc_STR("name of the generator")},
@@ -777,11 +806,11 @@ static PyGetSetDef gen_getsetlist[] = {
  {"gi_running", (getter)gen_getrunning, NULL, NULL},
  {"gi_frame", (getter)gen_getframe, NULL, NULL},
  {"gi_suspended", (getter)gen_getsuspended, NULL, NULL},
+ {"gi_code", (getter)gen_getcode, NULL, NULL},
  {NULL} /* Sentinel */
 };
 
 static PyMemberDef gen_memberlist[] = {
- {"gi_code", T_OBJECT, offsetof(PyGenObject, gi_code), READONLY|PY_AUDIT_READ},
  {NULL} /* Sentinel */
 };
 
@@ -790,7 +819,7 @@ gen_sizeof(PyGenObject *gen, PyObject *Py_UNUSED(ignored))
 {
  Py_ssize_t res;
  res = offsetof(PyGenObject, gi_iframe) + offsetof(_PyInterpreterFrame, localsplus);
- PyCodeObject *code = gen->gi_code;
+ PyCodeObject *code = _PyGen_GetCode(gen);
  res += _PyFrame_NumSlotsForCodeObject(code) * sizeof(PyObject *);
  return PyLong_FromSsize_t(res);
 }
@@ -878,7 +907,6 @@ make_gen(PyTypeObject *type, PyFunctionObject *func)
  return NULL;
  }
  gen->gi_frame_state = FRAME_CLEARED;
- gen->gi_code = (PyCodeObject *)Py_NewRef(func->func_code);
  gen->gi_weakreflist = NULL;
  gen->gi_exc_state.exc_value = NULL;
  gen->gi_exc_state.previous_item = NULL;
@@ -960,20 +988,18 @@ gen_new_with_qualname(PyTypeObject *type, PyFrameObject *f,
  f->f_frame = frame;
  frame->owner = FRAME_OWNED_BY_GENERATOR;
  assert(PyObject_GC_IsTracked((PyObject *)f));
- gen->gi_code = PyFrame_GetCode(f);
- Py_INCREF(gen->gi_code);
  Py_DECREF(f);
  gen->gi_weakreflist = NULL;
  gen->gi_exc_state.exc_value = NULL;
  gen->gi_exc_state.previous_item = NULL;
  if (name != NULL)
  gen->gi_name = Py_NewRef(name);
  else
- gen->gi_name = Py_NewRef(gen->gi_code->co_name);
+ gen->gi_name = Py_NewRef(_PyGen_GetCode(gen)->co_name);
  if (qualname != NULL)
  gen->gi_qualname = Py_NewRef(qualname);
  else
- gen->gi_qualname = Py_NewRef(gen->gi_code->co_qualname);
+ gen->gi_qualname = Py_NewRef(_PyGen_GetCode(gen)->co_qualname);
  _PyObject_GC_TRACK(gen);
  return (PyObject *)gen;
 }
@@ -1001,7 +1027,7 @@ static int
 gen_is_coroutine(PyObject *o)
 {
  if (PyGen_CheckExact(o)) {
- PyCodeObject *code = (PyCodeObject *)((PyGenObject*)o)->gi_code;
+ PyCodeObject *code = _PyGen_GetCode((PyGenObject*)o);
  if (code->co_flags & CO_ITERABLE_COROUTINE) {
  return 1;
  }
@@ -1110,6 +1136,12 @@ cr_getframe(PyCoroObject *coro, void *Py_UNUSED(ignored))
  return _gen_getframe((PyGenObject *)coro, "cr_frame");
 }
 
+static PyObject *
+cr_getcode(PyCoroObject *coro, void *Py_UNUSED(ignored))
+{
+ return _gen_getcode((PyGenObject *)coro, "cr_code");
+}
+
 
 static PyGetSetDef coro_getsetlist[] = {
  {"__name__", (getter)gen_get_name, (setter)gen_set_name,
@@ -1120,12 +1152,12 @@ static PyGetSetDef coro_getsetlist[] = {
  PyDoc_STR("object being awaited on, or None")},
  {"cr_running", (getter)cr_getrunning, NULL, NULL},
  {"cr_frame", (getter)cr_getframe, NULL, NULL},
+ {"cr_code", (getter)cr_getcode, NULL, NULL},
  {"cr_suspended", (getter)cr_getsuspended, NULL, NULL},
  {NULL} /* Sentinel */
 };
 
 static PyMemberDef coro_memberlist[] = {
- {"cr_code", T_OBJECT, offsetof(PyCoroObject, cr_code), READONLY|PY_AUDIT_READ},
  {"cr_origin", T_OBJECT, offsetof(PyCoroObject, cr_origin_or_finalizer), READONLY},
  {NULL} /* Sentinel */
 };
@@ -1514,6 +1546,12 @@ ag_getframe(PyAsyncGenObject *ag, void *Py_UNUSED(ignored))
  return _gen_getframe((PyGenObject *)ag, "ag_frame");
 }
 
+static PyObject *
+ag_getcode(PyGenObject *gen, void *Py_UNUSED(ignored))
+{
+ return _gen_getcode(gen, "ag__code");
+}
+
 static PyGetSetDef async_gen_getsetlist[] = {
  {"__name__", (getter)gen_get_name, (setter)gen_set_name,
  PyDoc_STR("name of the async generator")},
@@ -1522,13 +1560,13 @@ static PyGetSetDef async_gen_getsetlist[] = {
  {"ag_await", (getter)coro_get_cr_await, NULL,
  PyDoc_STR("object being awaited on, or None")},
  {"ag_frame", (getter)ag_getframe, NULL, NULL},
+ {"ag_code", (getter)ag_getcode, NULL, NULL},
  {NULL} /* Sentinel */
 };
 
 static PyMemberDef async_gen_memberlist[] = {
  {"ag_running", T_BOOL, offsetof(PyAsyncGenObject, ag_running_async),
  READONLY},
- {"ag_code", T_OBJECT, offsetof(PyAsyncGenObject, ag_code), READONLY|PY_AUDIT_READ},
  {NULL} /* Sentinel */
 };
 

Python/ceval.c

@@ -1604,41 +1604,6 @@ initialize_locals(PyThreadState *tstate, PyFunctionObject *func,
  return -1;
 }
 
-/* Consumes references to func, locals and all the args */
-static _PyInterpreterFrame *
-_PyEvalFramePushAndInit(PyThreadState *tstate, PyFunctionObject *func,
- PyObject *locals, PyObject* const* args,
- size_t argcount, PyObject *kwnames)
-{
- PyCodeObject * code = (PyCodeObject *)func->func_code;
- CALL_STAT_INC(frames_pushed);
- _PyInterpreterFrame *frame = _PyThreadState_PushFrame(tstate, code->co_framesize);
- if (frame == NULL) {
- goto fail;
- }
- _PyFrame_Initialize(frame, func, locals, code, 0);
- PyObject **localsarray = &frame->localsplus[0];
- if (initialize_locals(tstate, func, localsarray, args, argcount, kwnames)) {
- assert(frame->owner != FRAME_OWNED_BY_GENERATOR);
- _PyEvalFrameClearAndPop(tstate, frame);
- return NULL;
- }
- return frame;
-fail:
- /* Consume the references */
- for (size_t i = 0; i < argcount; i++) {
- Py_DECREF(args[i]);
- }
- if (kwnames) {
- Py_ssize_t kwcount = PyTuple_GET_SIZE(kwnames);
- for (Py_ssize_t i = 0; i < kwcount; i++) {
- Py_DECREF(args[i+argcount]);
- }
- }
- PyErr_NoMemory();
- return NULL;
-}
-
 static void
 clear_thread_frame(PyThreadState *tstate, _PyInterpreterFrame * frame)
 {
@@ -1649,7 +1614,8 @@ clear_thread_frame(PyThreadState *tstate, _PyInterpreterFrame * frame)
  tstate->datastack_top);
  tstate->c_recursion_remaining--;
  assert(frame->frame_obj == NULL || frame->frame_obj->f_frame == frame);
- _PyFrame_Clear(frame);
+ _PyFrame_ClearExceptCode(frame);
+ Py_DECREF(frame->f_code);
  tstate->c_recursion_remaining++;
  _PyThreadState_PopFrame(tstate, frame);
 }
@@ -1665,7 +1631,7 @@ clear_gen_frame(PyThreadState *tstate, _PyInterpreterFrame * frame)
  gen->gi_exc_state.previous_item = NULL;
  tstate->c_recursion_remaining--;
  assert(frame->frame_obj == NULL || frame->frame_obj->f_frame == frame);
-_PyFrame_Clear(frame);
+_PyFrame_ClearExceptCode(frame);
  tstate->c_recursion_remaining++;
  frame->previous = NULL;
 }
@@ -1681,6 +1647,39 @@ _PyEvalFrameClearAndPop(PyThreadState *tstate, _PyInterpreterFrame * frame)
  }
 }
 
+/* Consumes references to func, locals and all the args */
+static _PyInterpreterFrame *
+_PyEvalFramePushAndInit(PyThreadState *tstate, PyFunctionObject *func,
+ PyObject *locals, PyObject* const* args,
+ size_t argcount, PyObject *kwnames)
+{
+ PyCodeObject * code = (PyCodeObject *)func->func_code;
+ CALL_STAT_INC(frames_pushed);
+ _PyInterpreterFrame *frame = _PyThreadState_PushFrame(tstate, code->co_framesize);
+ if (frame == NULL) {
+ goto fail;
+ }
+ _PyFrame_Initialize(frame, func, locals, code, 0);
+ if (initialize_locals(tstate, func, frame->localsplus, args, argcount, kwnames)) {
+ assert(frame->owner == FRAME_OWNED_BY_THREAD);
+ clear_thread_frame(tstate, frame);
+ return NULL;
+ }
+ return frame;
+fail:
+ /* Consume the references */
+ for (size_t i = 0; i < argcount; i++) {
+ Py_DECREF(args[i]);
+ }
+ if (kwnames) {
+ Py_ssize_t kwcount = PyTuple_GET_SIZE(kwnames);
+ for (Py_ssize_t i = 0; i < kwcount; i++) {
+ Py_DECREF(args[i+argcount]);
+ }
+ }
+ PyErr_NoMemory();
+ return NULL;
+}
 
 PyObject *
 _PyEval_Vector(PyThreadState *tstate, PyFunctionObject *func,