tqchen commented on code in PR #684:
URL: https://github.com/apache/tvm-ffi/pull/684#discussion_r3642888220
##########
rust/tvm-ffi/src/object.rs:
##########
@@ -95,13 +99,120 @@ pub unsafe trait ObjectCoreWithExtraItems: ObjectCore {
/// used by the ffi Any system and not user facing
///
/// We mark as unsafe since it moves out the internal of the ObjectRef
+///
+/// # Safety
+///
+/// `data`, `into_data`, and `from_data` must preserve the same object
+/// allocation and form an ownership-preserving round trip. That allocation
must
+/// start with a valid `TVMFFIObject` header whose registered object-range
+/// runtime type index correctly describes its layout and inheritance.
+///
+/// When `Self` also implements [`AnyCompatible`], `copy_to_any_view` must
+/// produce a non-owning view, while `move_to_any` must transfer ownership of
+/// the same object pointer and dynamic type index. `move_from_any_after_check`
+/// must be able to reclaim that owned representation exactly once, and a true
+/// `check_any_strict` result must guarantee that both after-check constructors
+/// are valid for it.
pub unsafe trait ObjectRefCore: Sized + Clone {
type ContainerType: ObjectCore;
fn data(this: &Self) -> &ObjectArc<Self::ContainerType>;
fn into_data(this: Self) -> ObjectArc<Self::ContainerType>;
fn from_data(data: ObjectArc<Self::ContainerType>) -> Self;
}
+/// Check whether a runtime type index refers to `target_type_index` or one of
+/// its subtypes.
+///
+/// The subtype relation lives in the process-wide type table maintained by the
+/// tvm-ffi library: every registered type records its depth in the single
+/// inheritance tree together with the chain of its ancestors. The check is
+/// O(1) — if `target` really is an ancestor, it must appear in the candidate's
+/// ancestor array exactly at `target`'s depth.
+///
+/// This is a hidden support function for derive-generated object checks.
Object
+/// indices in the registered range must refer to entries in the runtime type
+/// table.
+#[doc(hidden)]
+#[inline(always)]
+pub fn is_instance_of(object_type_index: i32, target_type_index: i32) -> bool {
+ if object_type_index == target_type_index {
+ return true;
+ }
+ let object_begin = TypeIndex::kTVMFFIStaticObjectBegin as i32;
+ // Every registered object is an instance of the root Object type.
+ if target_type_index == object_begin {
+ return object_type_index >= object_begin;
+ }
+ // Only object types participate in the type hierarchy.
+ if object_type_index < object_begin || target_type_index < object_begin {
+ return false;
+ }
+ // Parent indices are always smaller than their descendants.
+ if object_type_index < target_type_index {
+ return false;
+ }
+ unsafe {
+ let object_info = TVMFFIGetTypeInfo(object_type_index);
+ let target_info = TVMFFIGetTypeInfo(target_type_index);
+ if object_info.is_null() || target_info.is_null() {
+ return false;
+ }
+ let target_depth = (*target_info).type_depth;
Review Comment:
might worthcheck other template trick for target_type_index. Note in the
case of C++ TargetType can be a type T, where things like type_depth can be
directly queried as a compile time constant rather than runtime
##########
rust/tvm-ffi/src/object.rs:
##########
@@ -95,13 +99,120 @@ pub unsafe trait ObjectCoreWithExtraItems: ObjectCore {
/// used by the ffi Any system and not user facing
///
/// We mark as unsafe since it moves out the internal of the ObjectRef
+///
+/// # Safety
+///
+/// `data`, `into_data`, and `from_data` must preserve the same object
+/// allocation and form an ownership-preserving round trip. That allocation
must
+/// start with a valid `TVMFFIObject` header whose registered object-range
+/// runtime type index correctly describes its layout and inheritance.
+///
+/// When `Self` also implements [`AnyCompatible`], `copy_to_any_view` must
+/// produce a non-owning view, while `move_to_any` must transfer ownership of
+/// the same object pointer and dynamic type index. `move_from_any_after_check`
+/// must be able to reclaim that owned representation exactly once, and a true
+/// `check_any_strict` result must guarantee that both after-check constructors
+/// are valid for it.
pub unsafe trait ObjectRefCore: Sized + Clone {
type ContainerType: ObjectCore;
fn data(this: &Self) -> &ObjectArc<Self::ContainerType>;
fn into_data(this: Self) -> ObjectArc<Self::ContainerType>;
fn from_data(data: ObjectArc<Self::ContainerType>) -> Self;
}
+/// Check whether a runtime type index refers to `target_type_index` or one of
+/// its subtypes.
+///
+/// The subtype relation lives in the process-wide type table maintained by the
+/// tvm-ffi library: every registered type records its depth in the single
+/// inheritance tree together with the chain of its ancestors. The check is
+/// O(1) — if `target` really is an ancestor, it must appear in the candidate's
+/// ancestor array exactly at `target`'s depth.
+///
+/// This is a hidden support function for derive-generated object checks.
Object
+/// indices in the registered range must refer to entries in the runtime type
+/// table.
+#[doc(hidden)]
+#[inline(always)]
+pub fn is_instance_of(object_type_index: i32, target_type_index: i32) -> bool {
+ if object_type_index == target_type_index {
+ return true;
+ }
+ let object_begin = TypeIndex::kTVMFFIStaticObjectBegin as i32;
+ // Every registered object is an instance of the root Object type.
+ if target_type_index == object_begin {
Review Comment:
given this is runtime check, likely not having the specialization is ok,
depending on how freq conversion to ObjectRef is.
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