[Gopalakrishnan Nallasamy (GopalakrishnanN)]

Description

Promotes the experimental EPContext named-buffer callback transport to the stable ONNX Runtime 1.31 C and C++ APIs.

• Adds stable read/write callback registration and immutable EP-facing snapshots of the callback and application-state pointers.
• Implements review option 3: removes max_data_size and the proposed read-options type, constructor, getter, setter, and release APIs. Registration and retrieval carry only callback/state pointers.
• Leaves allocation limits to the application callback and data validation/deserialization limits to the EP. ORT does not invoke the callback or inspect its result. The sample helper can enforce an EP-selected limit without putting that policy into the stable ABI.
• Adds append-only GetEpContextDataCallbackSupport READ/WRITE advertisement, gated on plugin API version 31. Unsupported participating EPs are rejected before Compile(), including the ORT-format read path. Registered callbacks cannot silently fall back to filesystem I/O.
• Removes the experimental EPContext lookup entries and C++ wrapper; experimental APIs have no stability guarantee.
• Updates the C++ wrappers, provider bridge, example EP, tests, and design document.
• Retains the early support query for providers that can produce external context data without Compile(), with VitisAI's direct-assignment lifecycle rationale documented.
• Includes the upstream GPU build fix from Replace old use of routing_record with routing_snapshot_ in onnxruntime/contrib_ops/cuda/moe/moe_quantization.cc. #32932 and the previously approved 2 KiB Android size-budget adjustment.

Provider/binding adoption follows in QNN (#32266), OpenVINO (#32267), C# (#32270), and Python (#32271). Those follow-ups need to use the finalized callback/state-only signatures.

Motivation and Context

This graduates the transport introduced experimentally by #28624 and refined by #29294 and #31195. Applications can keep external EPContext data in encrypted or application-managed storage without silently falling back to plaintext filesystem I/O.

Following the payload-policy review, the stable contract is limited to transport, ownership, and support negotiation. Centralized result-size validation would not itself prevent allocation inside the callback; passing a limit to the callback would still depend on callback/EP enforcement. Removing the policy avoids permanent API surface for a guarantee ORT does not provide.

Testing

Windows VS18 builds:

• cmake --build build\WindowsEpContextStable\RelWithDebInfo --config RelWithDebInfo --parallel 8 --target onnxruntime_shared_lib_test onnxruntime_autoep_test onnxruntime_test_all — passed.
• cmake --build build\WindowsEpContextMinimal\MinSizeRel --config MinSizeRel --parallel 4 --target onnxruntime_shared_lib_test — passed; minimal configuration disables exceptions, RTTI, and ML ops.

Tests run from build\WindowsEpContextStable\RelWithDebInfo\RelWithDebInfo:

• .\onnxruntime_shared_lib_test.exe --gtest_filter=EpContextDataApiTest.* — 14 passed, including immutable snapshots, cloning/lifetime, unchanged error outputs, and callback clearing.
• .\onnxruntime_autoep_test.exe --gtest_filter=*EpContext* — 25 passed, 2 skipped for unavailable Windows symlink privileges. Covers strict support negotiation, callback/file paths, and EP-selected helper size-limit boundaries.
• .\onnxruntime_test_all.exe --gtest_filter=InternalTestingEP.*EpContext*:InternalTestingEP.Nhwc* — 19 passed.

Tests run from build\WindowsEpContextMinimal\MinSizeRel\MinSizeRel:

• .\onnxruntime_shared_lib_test.exe --gtest_filter=EpContextDataApiTest.* — 2 passed.

Formatting and git diff --check passed. No references to the removed read-options API or runtime size fields remain in tracked files.

Not validated locally: GPU/Android builds, VitisAI/VAIP hardware behavior, other hardware EP integrations, or the full suite. The VitisAI lifecycle discussion remains open for reviewer confirmation.

[Copilot]

Pull request overview

Promotes EPContext callback transport to the stable ONNX Runtime 1.30 APIs with bounded reads and EP capability negotiation.

Changes:

• Adds stable C/C++ callback registration, configuration snapshots, and compatibility shims.
• Enforces read-size limits and READ/WRITE support advertisement.
• Migrates the example EP and expands compatibility and failure-path tests.

Reviewed changes

Copilot reviewed 38 out of 38 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
onnxruntime/test/shared_lib/test_ep_context_legacy_header.c	Checks legacy C header compatibility.
onnxruntime/test/shared_lib/test_ep_context_data_api.cc	Tests stable and legacy APIs.
onnxruntime/test/autoep/test_execution.cc	Tests support negotiation end-to-end.
onnxruntime/test/autoep/library/example_plugin_ep/ep.h	Declares stable config and support hook.
onnxruntime/test/autoep/library/example_plugin_ep/ep.cc	Advertises callback support.
onnxruntime/test/autoep/library/example_plugin_ep/ep_test_hooks.h	Adds support-advertisement test option.
onnxruntime/test/autoep/library/example_plugin_ep/ep_factory.cc	Configures support and stable snapshot.
onnxruntime/test/autoep/library/ep_context_data_utils.h	Enforces bounded reads.
onnxruntime/test/autoep/ep_context_data_utils_test.cc	Tests oversized payload rejection.
onnxruntime/core/session/provider_bridge_ort.cc	Bridges callback configuration.
onnxruntime/core/session/plugin_ep/ep_plugin_provider_interfaces.h	Declares plugin support query.
onnxruntime/core/session/plugin_ep/ep_plugin_provider_interfaces.cc	Implements versioned support query.
onnxruntime/core/session/plugin_ep/ep_api.h	Declares stable EP APIs.
onnxruntime/core/session/plugin_ep/ep_api.cc	Implements EP config snapshots.
onnxruntime/core/session/ort_apis.h	Declares stable read setter.
onnxruntime/core/session/onnxruntime_c_api.cc	Appends the read setter.
onnxruntime/core/session/inference_session.cc	Passes callback state to partitioning.
onnxruntime/core/session/experimental_c_api.cc	Forwards legacy APIs.
onnxruntime/core/session/compile_api.h	Declares stable write setter.
onnxruntime/core/session/compile_api.cc	Implements and registers write setter.
onnxruntime/core/session/abi_session_options.cc	Stores and exposes callback policy.
onnxruntime/core/session/abi_session_options_impl.h	Declares callback accessor.
onnxruntime/core/providers/shared_library/provider_wrappedtypes.h	Wraps provider callback access.
onnxruntime/core/providers/shared_library/provider_interfaces.h	Extends provider-host bridge.
onnxruntime/core/framework/session_options.h	Stores maximum read size.
onnxruntime/core/framework/graph_partitioner.h	Adds callback-registration input.
onnxruntime/core/framework/graph_partitioner.cc	Enforces EP support flags.
onnxruntime/core/framework/ep_context_options.h	Defines callback snapshot data.
include/onnxruntime/core/session/onnxruntime_experimental_cxx_api.h	Aliases deprecated C++ wrapper.
include/onnxruntime/core/session/onnxruntime_experimental_c_api.inc	Deprecates V28 lookup APIs.
include/onnxruntime/core/session/onnxruntime_experimental_c_api.h	Redirects types to stable API.
include/onnxruntime/core/session/onnxruntime_ep_c_api.h	Adds EP config and support APIs.
include/onnxruntime/core/session/onnxruntime_cxx_inline.h	Implements stable C++ wrappers.
include/onnxruntime/core/session/onnxruntime_cxx_api.h	Declares stable C++ wrappers.
include/onnxruntime/core/session/onnxruntime_c_api.h	Defines stable callback contracts.
include/onnxruntime/core/framework/execution_provider.h	Adds default support query.
docs/design/Compiled_Model_Encryption.md	Documents the stable contract.
cmake/onnxruntime_unittests.cmake	Builds the legacy-header test.

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[Gopalakrishnan Nallasamy (GopalakrishnanN)]

Python binding follow-up: #32271

[Copilot]

Pull request overview

Copilot reviewed 38 out of 38 changed files in this pull request and generated 3 comments.