codegen

README

ONNX Runtime API Code Generator

Tools to automatically generate Go binding code from ONNX Runtime C API header files.

Tools

1. ONNX Runtime Core API (tools/codegen/main.go)

Generates bindings for the core ONNX Runtime C API.

Usage

go run tools/codegen/main.go -version <VERSION> -out <OUTPUT_DIR>

Example:

go run tools/codegen/main.go -version 1.23.0 -out onnxruntime/internal/api/v23

Generated Files

api.go

• API version constant (APIVersion)
• APIBase structure (entry point)
• API structure (all function pointers, uintptr type)
• Function order matches the C header file

Header File Parsing

Recognizes the following 3 patterns:

1. ORT_API2_STATUS macro

   ORT_API2_STATUS(CreateSession, ...)
   

2. ORT_CLASS_RELEASE macro

   ORT_CLASS_RELEASE(Env);  // → ReleaseEnv
   

3. Direct function pointer definition

   void(ORT_API_CALL* GetVersion)(...);
   

---

2. ONNX Runtime GenAI API (tools/codegen/genai/main.go)

Generates bindings for the ONNX Runtime GenAI C API.

Usage

go run tools/codegen/genai/main.go -header <HEADER_PATH> -out <OUTPUT_DIR>

Example:

# First, download the GenAI library to get the header file
./download_genai.sh

# Then generate the bindings
go run tools/codegen/genai/main.go \
  -header ./libs/genai/0.11.0/include/ort_genai_c.h \
  -out genai/internal/api

Generated Files

api.go

• Opaque pointer types (OgaModel, OgaGenerator, OgaTokenizer, etc.)
• All types are uintptr to represent C opaque pointers

funcs.go

• Funcs structure with function pointers for all GenAI C API functions
• InitializeFuncs() to load functions from shared library using purego
• CheckResult() helper for error handling
• cStringToString() helper for C string conversion

Header File Parsing

Parses the GenAI C header (ort_genai_c.h) to extract:

1. Typedef struct declarations (opaque types)

   typedef struct OgaModel OgaModel;
   

2. Function declarations

   OGA_EXPORT OgaResult* OGA_API_CALL OgaCreateModel(const char* config_path, OgaModel** out);
   

Type Mapping

C Type	Go Type
void	(none)
void*	uintptr
bool	bool
int32_t	int32
int64_t	int64
size_t	uintptr
double	float64
char*	*byte
char**	**byte
OgaModel*	OgaModel (uintptr)
OgaModel**	*OgaModel
OgaResult*	OgaResult (uintptr)