feat: Introduce tvm_ffi::reflection::init<>
#32
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Pull Request Overview
This PR introduces the InitOf template function to simplify C++ constructor registration and adds experimental dataclass-style support for FFI classes.
- Adds
InitOf<T, Args...>helper to C++ for streamlined constructor registration - Introduces experimental
@c_classdecorator enabling dataclass syntax for Python FFI proxies - Creates test infrastructure with inheritance hierarchy for validating the new features
Reviewed Changes
Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.
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| File | Description |
|---|---|
| include/tvm/ffi/reflection/registry.h | Adds InitOf template helper for constructor registration |
| src/ffi/extra/testing.cc | Creates C++ test classes using InitOf for constructor registration |
| python/tvm_ffi/dataclasses/ | New module providing @c_class decorator and field helper for dataclass syntax |
| python/tvm_ffi/testing.py | Python proxy classes demonstrating dataclass-style FFI usage |
| tests/python/test_dataclasses_c_class.py | Test cases validating the dataclass FFI functionality |
| python/tvm_ffi/cython/type_info.pxi | Adds dataclass_field attribute to TypeField |
| python/tvm_ffi/core.pyi | Type stub updates for new dataclass_field attribute |
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tqchen
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tvm_ffi::reflection::init<>
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looks great, let us add a testcase to tests/cpp/testing_object.h
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lgtm modulo on minor improvement
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@tqchen To summarize the latest change:
Please re-review 🙏 |
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Please take another look @tqchen! |
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Depends on #32. This PR introduces an experimental `@c_class` decorator that enables Python dataclass-like syntax for exposing C++ objects through TVM FFI. The decorator automatically handles field reflection, inheritance, and constructor generation for FFI-backed classes. ## Example On C++ side, register types using `tvm::ffi::reflection::ObjectDef<>`: ```C++ TVM_FFI_STATIC_INIT_BLOCK() { namespace refl = tvm::ffi::reflection; refl::ObjectDef<MyClass>() .def_static("__init__", [](int64_t v_i64, int32_t v_i32, double v_f64, float v_f32) -> Any { return ObjectRef(ffi::make_object<MyClass>(v_i64, v_i32, v_f64, v_f32)); }) .def_rw("v_i64", &MyClass::v_i64) .def_rw("v_i32", &MyClass::v_i32) .def_rw("v_f64", &MyClass::v_f64) .def_rw("v_f32", &MyClass::v_f32); } ``` Mirror the same structure in Python using dataclass-style annotations: ```python from tvm_ffi.dataclasses import c_class, field @c_class("example.MyClass") class MyClass: v_i64: int v_i32: int v_f64: float = field(default=0.0) v_f32: float = field(default_factory=lambda: 1.0) obj = MyClass(v_i64=4, v_i32=8) obj.v_f64 = 3.14 # transparently forwards to the underlying C++ object ``` ## Future work Supporting as many dataclass features as possible, including: `repr`, `init`, `order`, etc.
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This PR introduces
tvm_ffi::reflection::init<ObjectType, Args...>, which can be used to simplify registration of__init__method.