feat(cython): expose additional C API symbols in base.pxi

[junrushao]

Summary

• Add Cython declarations for type-registration functions (TVMFFITypeGetOrAllocIndex, TVMFFITypeRegisterField, TVMFFITypeRegisterMetadata, TVMFFITypeRegisterAttr, TVMFFIErrorSetRaisedFromCStr) so Python-side type registration can call these symbols directly through Cython
• Add missing field-flag constants (SEqHashIgnore, SEqHashDef, ReprOff, CompareOff, HashOff) and the TVMFFISEqHashKind enum
• Fix TVMFFITypeMetadata.total_size type (int64_t -> int32_t) and add structural_eq_hash_kind field to match the C struct layout
• Add cause_chain and extra_context fields to the error info struct

Test plan

• Existing CI tests pass (no behavioral change, declarations only)
• Verify Cython compilation succeeds with the new declarations via uv pip install --force-reinstall --verbose -e .

🤖 Generated with Claude Code

[gemini-code-assist]

Summary of Changes

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This pull request enhances the Cython FFI bindings by exposing critical C API symbols and constants, ensuring better alignment between the Python and C interfaces. These changes facilitate more robust Python-side type registration, error handling, and structural equality hashing by providing direct access to underlying C functionalities and correcting struct definitions.

Highlights

• Cython Declarations: Exposed additional C API symbols for type-registration functions, allowing Python-side type registration to directly call these through Cython.
• Field Flags and Enum: Added missing field-flag constants (SEqHashIgnore, SEqHashDef, ReprOff, CompareOff, HashOff) and the TVMFFISEqHashKind enum to align with C API definitions.
• Type Metadata Struct Alignment: Corrected the type of TVMFFITypeMetadata.total_size from int64_t to int32_t and added the structural_eq_hash_kind field to match the C struct layout.
• Error Info Struct Enhancement: Added cause_chain and extra_context fields to the error information struct for more comprehensive error reporting.

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Changelog

• python/tvm_ffi/cython/base.pxi
  • Added cause_chain and extra_context fields to the TVMFFIErrorInfo struct.
  • Introduced new field flag constants: SEqHashIgnore, SEqHashDef, ReprOff, CompareOff, and HashOff.
  • Defined the TVMFFISEqHashKind enum.
  • Corrected the type of TVMFFITypeMetadata.total_size to int32_t and added structural_eq_hash_kind.
  • Exposed several C API functions for type registration and error handling, including TVMFFITypeGetOrAllocIndex, TVMFFITypeRegisterField, TVMFFITypeRegisterMetadata, TVMFFITypeRegisterAttr, and TVMFFIErrorSetRaisedFromCStr.

Activity

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[gemini-code-assist]

Code Review

This pull request updates the Cython definitions in python/tvm_ffi/cython/base.pxi to expose additional C API symbols. The changes include adding new fields to TVMFFIErrorCell, new constants to TVMFFIFieldFlagBitMask, defining the TVMFFISEqHashKind enum, and updating TVMFFITypeMetadata to match the C struct layout. Additionally, several new function declarations from the FFI C API are added. The changes align the Cython definitions with the C header files and appear correct.