Move typeid into vtable (#6231)

* Move typeid into vtable

* Bump rust-version

Cargo.toml

@@ -131,7 +131,7 @@ members = [
 version = "0.4.0"
 authors = ["RustPython Team"]
 edition = "2024"
-rust-version = "1.89.0"
+rust-version = "1.91.0"
 repository = "https://github.com/RustPython/RustPython"
 license = "MIT"
 

crates/derive-impl/src/pyclass.rs

@@ -635,10 +635,7 @@ pub(crate) fn impl_pyclass(attr: PunctuatedNestedMeta, item: Item) -> Result<Tok
         quote! {
             // static_assertions::const_assert!(std::mem::size_of::<#base_type>() <= std::mem::size_of::<#ident>());
             impl ::rustpython_vm::PyPayload for #ident {
-                #[inline]
-                fn payload_type_id() -> ::std::any::TypeId {
-                    <#base_type as ::rustpython_vm::PyPayload>::payload_type_id()
-                }
+                const PAYLOAD_TYPE_ID: ::core::any::TypeId = <#base_type as ::rustpython_vm::PyPayload>::PAYLOAD_TYPE_ID;
 
                 #[inline]
                 fn validate_downcastable_from(obj: &::rustpython_vm::PyObject) -> bool {

crates/derive-impl/src/pystructseq.rs

@@ -592,10 +592,7 @@ pub(crate) fn impl_pystruct_sequence(
 
         // Subtype uses base type's payload_type_id
         impl ::rustpython_vm::PyPayload for #pytype_ident {
-            #[inline]
-            fn payload_type_id() -> ::std::any::TypeId {
-                <::rustpython_vm::builtins::PyTuple as ::rustpython_vm::PyPayload>::payload_type_id()
-            }
+            const PAYLOAD_TYPE_ID: ::core::any::TypeId = <::rustpython_vm::builtins::PyTuple as ::rustpython_vm::PyPayload>::PAYLOAD_TYPE_ID;
 
             #[inline]
             fn validate_downcastable_from(obj: &::rustpython_vm::PyObject) -> bool {

crates/vm/src/builtins/str.rs

@@ -1935,9 +1935,7 @@ impl PyPayload for PyUtf8Str {
         ctx.types.str_type
     }
 
-    fn payload_type_id() -> core::any::TypeId {
-        core::any::TypeId::of::<PyStr>()
-    }
+    const PAYLOAD_TYPE_ID: core::any::TypeId = core::any::TypeId::of::<PyStr>();
 
     fn validate_downcastable_from(obj: &PyObject) -> bool {
         // SAFETY: we know the object is a PyStr in this context

crates/vm/src/object/core.rs

@@ -105,8 +105,6 @@ pub(super) unsafe fn try_trace_obj<T: PyPayload>(x: &PyObject, tracer_fn: &mut T
 #[repr(C)]
 pub(super) struct PyInner<T> {
     pub(super) ref_count: RefCount,
-    // TODO: move typeid into vtable once TypeId::of is const
-    pub(super) typeid: TypeId,
     pub(super) vtable: &'static PyObjVTable,
 
     pub(super) typ: PyAtomicRef<PyType>, // __class__ member
@@ -449,7 +447,6 @@ impl<T: PyPayload + core::fmt::Debug> PyInner<T> {
         let member_count = typ.slots.member_count;
         Box::new(Self {
             ref_count: RefCount::new(),
-            typeid: T::payload_type_id(),
             vtable: PyObjVTable::of::<T>(),
             typ: PyAtomicRef::from(typ),
             dict: dict.map(InstanceDict::new),
@@ -639,7 +636,7 @@ impl PyObject {
     #[deprecated(note = "use downcastable instead")]
     #[inline(always)]
     pub fn payload_is<T: PyPayload>(&self) -> bool {
-        self.0.typeid == T::payload_type_id()
+        self.0.vtable.typeid == T::PAYLOAD_TYPE_ID
     }
 
     /// Force to return payload as T.
@@ -722,7 +719,7 @@ impl PyObject {
 
     #[inline]
     pub(crate) fn typeid(&self) -> TypeId {
-        self.0.typeid
+        self.0.vtable.typeid
     }
 
     /// Check if this object can be downcast to T.
@@ -1276,7 +1273,6 @@ pub(crate) fn init_type_hierarchy() -> (PyTypeRef, PyTypeRef, PyTypeRef) {
         let type_type_ptr = Box::into_raw(Box::new(partially_init!(
             PyInner::<PyType> {
                 ref_count: RefCount::new(),
-                typeid: TypeId::of::<PyType>(),
                 vtable: PyObjVTable::of::<PyType>(),
                 dict: None,
                 weak_list: WeakRefList::new(),
@@ -1288,7 +1284,6 @@ pub(crate) fn init_type_hierarchy() -> (PyTypeRef, PyTypeRef, PyTypeRef) {
         let object_type_ptr = Box::into_raw(Box::new(partially_init!(
             PyInner::<PyType> {
                 ref_count: RefCount::new(),
-                typeid: TypeId::of::<PyType>(),
                 vtable: PyObjVTable::of::<PyType>(),
                 dict: None,
                 weak_list: WeakRefList::new(),

crates/vm/src/object/payload.rs

@@ -26,15 +26,12 @@ pub(crate) fn cold_downcast_type_error(
 }
 
 pub trait PyPayload: MaybeTraverse + PyThreadingConstraint + Sized + 'static {
-    #[inline]
-    fn payload_type_id() -> core::any::TypeId {
-        core::any::TypeId::of::<Self>()
-    }
+    const PAYLOAD_TYPE_ID: core::any::TypeId = core::any::TypeId::of::<Self>();
 
     /// # Safety: this function should only be called if `payload_type_id` matches the type of `obj`.
     #[inline]
     fn downcastable_from(obj: &PyObject) -> bool {
-        obj.typeid() == Self::payload_type_id() && Self::validate_downcastable_from(obj)
+        obj.typeid() == Self::PAYLOAD_TYPE_ID && Self::validate_downcastable_from(obj)
     }
 
     #[inline]

crates/vm/src/object/traverse_object.rs

@@ -1,4 +1,5 @@
 use alloc::fmt;
+use core::any::TypeId;
 
 use crate::{
     PyObject,
@@ -11,6 +12,7 @@ use crate::{
 use super::{Traverse, TraverseFn};
 
 pub(in crate::object) struct PyObjVTable {
+    pub(in crate::object) typeid: TypeId,
     pub(in crate::object) drop_dealloc: unsafe fn(*mut PyObject),
     pub(in crate::object) debug: unsafe fn(&PyObject, &mut fmt::Formatter<'_>) -> fmt::Result,
     pub(in crate::object) trace: Option<unsafe fn(&PyObject, &mut TraverseFn<'_>)>,
@@ -19,6 +21,7 @@ pub(in crate::object) struct PyObjVTable {
 impl PyObjVTable {
     pub const fn of<T: PyObjectPayload>() -> &'static Self {
         &Self {
+            typeid: T::PAYLOAD_TYPE_ID,
             drop_dealloc: drop_dealloc_obj::<T>,
             debug: debug_obj::<T>,
             trace: const {