gh-117376: Make code objects use deferred reference counting (#117823)

We want code objects to use deferred reference counting in the
free-threaded build. This requires them to be tracked by the GC, so we
set `Py_TPFLAGS_HAVE_GC` in the free-threaded build, but not the default
build.
This commit is contained in:
Sam Gross 2024-04-16 12:42:53 -04:00 committed by GitHub
parent a734fd5cf7
commit 241ed5f2cd
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3 changed files with 38 additions and 3 deletions

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@ -1,7 +1,7 @@
import unittest
from contextlib import contextmanager, ExitStack
from test.support import catch_unraisable_exception, import_helper
from test.support import catch_unraisable_exception, import_helper, gc_collect
# Skip this test if the _testcapi module isn't available.
@ -372,6 +372,7 @@ class TestCodeObjectWatchers(unittest.TestCase):
def assert_event_counts(self, exp_created_0, exp_destroyed_0,
exp_created_1, exp_destroyed_1):
gc_collect() # code objects are collected by GC in free-threaded build
self.assertEqual(
exp_created_0, _testcapi.get_code_watcher_num_created_events(0))
self.assertEqual(
@ -432,6 +433,7 @@ class TestCodeObjectWatchers(unittest.TestCase):
with self.code_watcher(2):
with catch_unraisable_exception() as cm:
del co
gc_collect()
self.assertEqual(str(cm.unraisable.exc_value), "boom!")

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@ -226,7 +226,9 @@ class GCTests(unittest.TestCase):
exec("def f(): pass\n", d)
gc.collect()
del d
self.assertEqual(gc.collect(), 2)
# In the free-threaded build, the count returned by `gc.collect()`
# is 3 because it includes f's code object.
self.assertIn(gc.collect(), (2, 3))
def test_function_tp_clear_leaves_consistent_state(self):
# https://github.com/python/cpython/issues/91636

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@ -6,6 +6,7 @@
#include "pycore_code.h" // _PyCodeConstructor
#include "pycore_frame.h" // FRAME_SPECIALS_SIZE
#include "pycore_interp.h" // PyInterpreterState.co_extra_freefuncs
#include "pycore_object.h" // _PyObject_SetDeferredRefcount
#include "pycore_opcode_metadata.h" // _PyOpcode_Deopt, _PyOpcode_Caches
#include "pycore_opcode_utils.h" // RESUME_AT_FUNC_START
#include "pycore_pystate.h" // _PyInterpreterState_GET()
@ -557,13 +558,22 @@ _PyCode_New(struct _PyCodeConstructor *con)
}
Py_ssize_t size = PyBytes_GET_SIZE(con->code) / sizeof(_Py_CODEUNIT);
PyCodeObject *co = PyObject_NewVar(PyCodeObject, &PyCode_Type, size);
PyCodeObject *co;
#ifdef Py_GIL_DISABLED
co = PyObject_GC_NewVar(PyCodeObject, &PyCode_Type, size);
#else
co = PyObject_NewVar(PyCodeObject, &PyCode_Type, size);
#endif
if (co == NULL) {
Py_XDECREF(replacement_locations);
PyErr_NoMemory();
return NULL;
}
init_code(co, con);
#ifdef Py_GIL_DISABLED
_PyObject_SetDeferredRefcount((PyObject *)co);
_PyObject_GC_TRACK(co);
#endif
Py_XDECREF(replacement_locations);
return co;
}
@ -1710,6 +1720,10 @@ code_dealloc(PyCodeObject *co)
}
Py_SET_REFCNT(co, 0);
#ifdef Py_GIL_DISABLED
PyObject_GC_UnTrack(co);
#endif
_PyFunction_ClearCodeByVersion(co->co_version);
if (co->co_extra != NULL) {
PyInterpreterState *interp = _PyInterpreterState_GET();
@ -1752,6 +1766,15 @@ code_dealloc(PyCodeObject *co)
PyObject_Free(co);
}
#ifdef Py_GIL_DISABLED
static int
code_traverse(PyCodeObject *co, visitproc visit, void *arg)
{
Py_VISIT(co->co_consts);
return 0;
}
#endif
static PyObject *
code_repr(PyCodeObject *co)
{
@ -2196,9 +2219,17 @@ PyTypeObject PyCode_Type = {
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
#ifdef Py_GIL_DISABLED
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
#else
Py_TPFLAGS_DEFAULT, /* tp_flags */
#endif
code_new__doc__, /* tp_doc */
#ifdef Py_GIL_DISABLED
(traverseproc)code_traverse, /* tp_traverse */
#else
0, /* tp_traverse */
#endif
0, /* tp_clear */
code_richcompare, /* tp_richcompare */
offsetof(PyCodeObject, co_weakreflist), /* tp_weaklistoffset */