### **Overview**
This PR implements native Python function support in TVM Relax through
the `@I.pyfunc` decorator and `BasePyModule`, which enable seamless
integration between TVM's compilation pipeline and Python/PyTorch runtime
environments. This enhancement allows users to write Python functions
directly in TVMScript that can interoperate with Relax and TIR functions
that provides enhanced debugging capabilities and leveraging existing
PyTorch operator libraries.
### **Key Features**
**TVMScript Parser Enhancement**
- `@I.pyfunc` decorator: Marks Python functions for integration into IRModules
- Dual storage format: Stores both raw string representation (for TVMScript
printing) and captured PackedFunc (for runtime execution)
- ExternFunc representation: Each Python function is represented as an
ExternFunc node with attributes storing source code and runtime wrapper
**Complete BasePyModule Implementation**
- DLPack-based tensor conversion: Seamless conversion between PyTorch
tensors and TVM NDArrays
- Cross-function interoperability: Python functions can call Relax/TIR
functions and vice versa
- JIT compilation: Delays compilation until module instantiation for flexible
late-stage modifications
- Dynamic function registration: Supports runtime addition of Python functions
### Future Work
- TVMScript printer for IRModules with Python functions: Print IRModules
in proper format with high-level operator mapping from Relax ops to PyTorch
ops, handling symbolic shapes
- R.call_py_func primitive: Introduce Relax primitive to invoke corresponding
PackedFunc of specified Python functions at runtime
This PR introduces some minor restructuring of the `python/tvm/script`
folder structure to make it more convenient for future upstreaming.
Co-authored-by: Yaxing Cai <caiyaxing666@gmail.com>
Tianqi Chen