Skip to content

impl gc finialized #6689

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
youknowone merged 2 commits into from
Jan 10, 2026
Merged

impl gc finialized #6689

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
7f1a713
impl gc finialized
youknowone Jan 10, 2026
9b3532d
Auto-format: cargo fmt --all
github-actions[bot] Jan 10, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 0 additions & 4 deletions Lib/_opcode_metadata.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,10 +4,6 @@

_specializations = {}





_specialized_opmap = {}

opmap = {
Expand Down
54 changes: 52 additions & 2 deletions crates/vm/src/object/core.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -99,13 +99,40 @@ pub(super) unsafe fn try_trace_obj<T: PyPayload>(x: &PyObject, tracer_fn: &mut T
payload.try_traverse(tracer_fn)
}

bitflags::bitflags! {
/// GC bits for free-threading support (like ob_gc_bits in Py_GIL_DISABLED)
/// These bits are stored in a separate atomic field for lock-free access.
/// See Include/internal/pycore_gc.h
#[derive(Copy, Clone, Debug, Default)]
pub(crate) struct GcBits: u8 {
/// Tracked by the GC
const TRACKED = 1 << 0;
/// tp_finalize was called (prevents __del__ from being called twice)
const FINALIZED = 1 << 1;
/// Object is unreachable (during GC collection)
const UNREACHABLE = 1 << 2;
/// Object is frozen (immutable)
const FROZEN = 1 << 3;
/// Memory the object references is shared between multiple threads
/// and needs special handling when freeing due to possible in-flight lock-free reads
const SHARED = 1 << 4;
/// Memory of the object itself is shared between multiple threads
/// Objects with this bit that are GC objects will automatically be delay-freed
const SHARED_INLINE = 1 << 5;
/// Use deferred reference counting
const DEFERRED = 1 << 6;
}
}

/// This is an actual python object. It consists of a `typ` which is the
/// python class, and carries some rust payload optionally. This rust
/// payload can be a rust float or rust int in case of float and int objects.
#[repr(C)]
pub(super) struct PyInner<T> {
pub(super) ref_count: RefCount,
pub(super) vtable: &'static PyObjVTable,
/// GC bits for free-threading (like ob_gc_bits)
pub(super) gc_bits: PyAtomic<u8>,

pub(super) typ: PyAtomicRef<PyType>, // __class__ member
pub(super) dict: Option<InstanceDict>,
Expand Down Expand Up @@ -448,6 +475,7 @@ impl<T: PyPayload + core::fmt::Debug> PyInner<T> {
Box::new(Self {
ref_count: RefCount::new(),
vtable: PyObjVTable::of::<T>(),
gc_bits: Radium::new(0),
typ: PyAtomicRef::from(typ),
dict: dict.map(InstanceDict::new),
weak_list: WeakRefList::new(),
Expand Down Expand Up @@ -780,6 +808,23 @@ impl PyObject {
self
}

/// Check if the object has been finalized (__del__ already called).
/// _PyGC_FINALIZED in Py_GIL_DISABLED mode.
#[inline]
fn gc_finalized(&self) -> bool {
use core::sync::atomic::Ordering::Relaxed;
GcBits::from_bits_retain(self.0.gc_bits.load(Relaxed)).contains(GcBits::FINALIZED)
}

/// Mark the object as finalized. Should be called before __del__.
/// _PyGC_SET_FINALIZED in Py_GIL_DISABLED mode.
#[inline]
fn set_gc_finalized(&self) {
use core::sync::atomic::Ordering::Relaxed;
// Atomic RMW to avoid clobbering other concurrent bit updates.
self.0.gc_bits.fetch_or(GcBits::FINALIZED.bits(), Relaxed);
}

#[inline(always)] // the outer function is never inlined
fn drop_slow_inner(&self) -> Result<(), ()> {
// __del__ is mostly not implemented
Expand Down Expand Up @@ -809,9 +854,12 @@ impl PyObject {
}
}

// CPython-compatible drop implementation
// __del__ should only be called once (like _PyGC_FINALIZED check in GIL_DISABLED)
let del = self.class().slots.del.load();
if let Some(slot_del) = del {
if let Some(slot_del) = del
&& !self.gc_finalized()
{
self.set_gc_finalized();
call_slot_del(self, slot_del)?;
}
if let Some(wrl) = self.weak_ref_list() {
Expand Down Expand Up @@ -1274,6 +1322,7 @@ pub(crate) fn init_type_hierarchy() -> (PyTypeRef, PyTypeRef, PyTypeRef) {
PyInner::<PyType> {
ref_count: RefCount::new(),
vtable: PyObjVTable::of::<PyType>(),
gc_bits: Radium::new(0),
dict: None,
weak_list: WeakRefList::new(),
payload: type_payload,
Expand All @@ -1285,6 +1334,7 @@ pub(crate) fn init_type_hierarchy() -> (PyTypeRef, PyTypeRef, PyTypeRef) {
PyInner::<PyType> {
ref_count: RefCount::new(),
vtable: PyObjVTable::of::<PyType>(),
gc_bits: Radium::new(0),
dict: None,
weak_list: WeakRefList::new(),
payload: object_payload,
Expand Down
Loading