[CUDA] Make cuDNN optional at runtime (#29252)
## Summary
Make cuDNN an optional runtime dependency for the CUDA Execution
Provider and CUDA Plugin EP. The build still uses cuDNN headers, but
provider binaries no longer directly depend on cuDNN shared libraries;
cuDNN is loaded lazily when enabled and available, while no-cuDNN runs
use native CUDA paths where available and report `NOT_IMPLEMENTED` for
kernels that still require cuDNN.
This also adds CI to validate no-cuDNN runtime environments.
## Key Changes
| Area | Changes |
|---|---|
| CUDA EP runtime loading | Added a dynamic cuDNN loader and cuDNN
symbol trampolines so CUDA provider binaries can avoid a direct cuDNN
dependency. |
| Provider options | Added `enable_cudnn`; removed `cudnn_path` from
CUDA EP and CUDA Plugin EP provider configuration. |
| CUDA Plugin EP | Wired optional cuDNN behavior through plugin EP
config, kernel adapters, stream handles, and plugin utilities. |
| Python preload behavior | Updated Python CUDA preload handling so
cuDNN remains an optional dependency instead of an unconditional
import/runtime requirement. |
| Tests | Added/updated provider option coverage and CUDA Plugin EP
no-cuDNN mode using `ORT_TEST_CUDA_PLUGIN_NO_CUDNN=1`. |
| CI | Added Linux and Windows CUDA no-cuDNN workflows that build with
cuDNN headers, exclude cuDNN from the runtime path, verify no direct
cuDNN dependency, and run targeted tests. |
| Documentation | Added `docs/CUDA_cuDNN_Optional_Design.md` and updated
CUDA Plugin EP docs for no-cuDNN behavior and validation. |
## Testing
Validated locally on Linux CUDA 13:
- Rebuilt CUDA EP / CUDA Plugin EP with cuDNN headers available at build
time.
- Verified provider binaries have no direct cuDNN dependency:
- `readelf -d ... | grep NEEDED | grep -i cudnn || echo "no cudnn
DT_NEEDED"`
- `ldd ... | grep -i cudnn || echo "no cudnn in ldd"`
- Ran CUDA Plugin EP no-cuDNN validation:
- `bash .env/cuda_130_plugin_no_cudnn.sh --test_plugin`
- Result: `Ran 87 tests`, `OK (skipped=17)`
Additional CI coverage is included for Linux and Windows no-cuDNN CUDA
validation.
