[Plugin EP] Port graph capture/replay APIs

[adrianlizarraga]

NOTE: This PR cannot be merged until the ORT version is updated to 1.26.0 in the main branch

Description

Ports graph capture/replay APIs (e.g., CUDA Graph) to the Plugin EP (OrtEp) C API so that plugin-based execution providers can participate in ORT-managed graph capture and replay.

What changed

New Plugin EP C API functions (onnxruntime_ep_c_api.h):

• OrtEp::IsGraphCaptureEnabled — indicates whether the EP has graph capture enabled.
• OrtEp::IsGraphCaptured — indicates whether a graph has been captured for a given annotation ID.
• OrtEp::ReplayGraph — replays a previously captured graph.
• OrtEp::GetGraphCaptureNodeAssignmentPolicy — returns the node assignment validation policy for graph capture.

All four are optional (NULL defaults to safe behavior) and version-gated (ort_version_supported >= 26).
If IsGraphCaptureEnabled returns true, IsGraphCaptured and ReplayGraph must also be implemented;
otherwise PluginExecutionProvider logs a warning and disables graph capture for that EP.

New OrtGraphCaptureNodeAssignmentPolicy enum (onnxruntime_ep_c_api.h):
Replaces the hardcoded EP-name checks in InferenceSession::Initialize() with a policy-based approach:

• ALL_NODES_ON_EP — all nodes must be on the target EP (e.g., TensorRT).
• ALLOW_CPU_FOR_SHAPES — CPU nodes allowed for shape computation if no memcpy nodes exist (e.g., CUDA, WebGPU, DML).

Refactored InferenceSession graph capture selection (inference_session.cc):

• Removed the hardcoded graph_support_ep_list and per-EP strcmp checks.
• Now iterates over all registered EPs and uses IsGraphCaptureEnabled() + GetGraphCaptureNodeAssignmentPolicy() to select and validate the graph-capturing EP.
• AreAllComputeNodesAssignedToCudaOrJsOrDmlEpWebGpuEp() → generalized to AreAllComputeNodesAssignedToEpOrCpu(), which also requires at least one node on the target EP.
• IExecutionProvider::GetGraphCaptureNodeAssignmentPolicy() added to the base class (defaults to ALL_NODES_ON_EP).

Bounded graph capture recursion (inference_session.cc/h):

• Run() now delegates to RunImpl() with a graph_capture_depth parameter.
• Caps internal run attempts at kMaxGraphCaptureRunAttempts = 8, returning a clear error if the EP never reports IsGraphCaptured() == true.

EP implementations:

• WebGPU plugin EP: Fully implements all four graph capture APIs by forwarding to the underlying IExecutionProvider.
• CUDA plugin EP: Stubs with TODOs (returns disabled/not-implemented).
• NvTensorRTRTX EP: IsGraphCaptureEnabled() now returns false since this EP manages graph capture internally (not via ORT).

C++ wrapper (onnxruntime_cxx_api.h / onnxruntime_cxx_inline.h):

• Added Ort::Env::CopyTensor() convenience overload for copying a single tensor (wraps CopyTensors with num_tensors=1).

Tests

• ep_plugin_provider_test.cc: Unit tests for each new PluginExecutionProvider graph capture method, including NULL function pointer defaults, version < 26 backward compatibility, and validation that IsGraphCaptureEnabled() returns false when IsGraphCaptured or ReplayGraph are NULL.
• test_graph_capture.cc: End-to-end test for WebGPU plugin EP graph capture/replay using IO binding (warm-up + capture run, then replay with different inputs).

Motivation and Context

Previously, graph capture support was limited to a hardcoded list of EPs (kCudaExecutionProvider, kTensorrtExecutionProvider, kJsExecutionProvider, kWebGpuExecutionProvider, kDmlExecutionProvider) with EP-specific validation logic in InferenceSession. This made it impossible for plugin EPs to participate in ORT-managed graph capture/replay without modifying the core session code.

This PR makes graph capture/replay extensible to any EP, including out-of-tree plugin EPs, by exposing it through the OrtEp C API.

[Copilot]

Pull request overview

This PR (draft) ports graph capture/replay support to the Plugin EP pathway by extending the OrtEp C API, wiring those callbacks through the plugin EP provider wrapper, and updating session initialization logic to validate/capture based on an EP-provided node-assignment policy.

Changes:

• Bump ORT version/API version to 1.26.0 / ORT_API_VERSION=26 and add new OrtEp graph capture/replay callbacks plus OrtGraphCaptureNodeAssignmentPolicy.
• Update InferenceSession::Initialize() to select any EP with graph capture enabled, validate graph assignment via EP policy, and cache a single EP for replay.
• Add/extend tests for plugin EP graph capture APIs and add an end-to-end autoep WebGPU plugin EP graph capture/replay test.

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
VERSION_NUMBER	Bumps runtime version to 1.26.0.
include/onnxruntime/core/session/onnxruntime_c_api.h	Bumps ORT_API_VERSION to 26.
onnxruntime/core/session/onnxruntime_c_api.cc	Updates version string static assert to 1.26.0.
include/onnxruntime/core/session/onnxruntime_ep_c_api.h	Adds graph capture/replay callbacks to OrtEp and introduces OrtGraphCaptureNodeAssignmentPolicy.
include/onnxruntime/core/framework/execution_provider.h	Adds IExecutionProvider::GetGraphCaptureNodeAssignmentPolicy() with a strict default.
onnxruntime/core/session/inference_session.cc	Generalizes graph-capture EP selection/validation and uses EP-specified node assignment policy.
onnxruntime/core/session/plugin_ep/ep_plugin_provider_interfaces.h	Exposes graph capture/replay APIs on PluginExecutionProvider.
onnxruntime/core/session/plugin_ep/ep_plugin_provider_interfaces.cc	Implements plugin-side forwarding for graph capture/replay and policy query with version gating.
onnxruntime/core/providers/webgpu/ep/ep.h	Declares plugin adapter entrypoints for graph capture/replay and assignment policy.
onnxruntime/core/providers/webgpu/ep/ep.cc	Wires WebGPU plugin EP adapter function pointers and forwards to EP impl.
onnxruntime/core/providers/webgpu/webgpu_execution_provider.h	Returns ALLOW_CPU_FOR_SHAPES policy for WebGPU EP.
onnxruntime/core/providers/js/js_execution_provider.h	Returns ALLOW_CPU_FOR_SHAPES policy for JS EP.
onnxruntime/core/providers/dml/DmlExecutionProvider/src/ExecutionProvider.h	Returns ALLOW_CPU_FOR_SHAPES policy for DML EP wrapper.
onnxruntime/core/providers/cuda/cuda_execution_provider.h	Returns ALLOW_CPU_FOR_SHAPES policy for CUDA EP.
onnxruntime/core/providers/cuda/plugin/cuda_ep.h	Declares plugin CUDA EP adapter entrypoints for graph capture/replay and policy.
onnxruntime/core/providers/cuda/plugin/cuda_ep.cc	Wires plugin CUDA EP adapter function pointers (currently stubbed).
onnxruntime/test/framework/ep_plugin_provider_test.cc	Adds unit tests for plugin EP graph capture/replay function-pointer behavior and version gating.
onnxruntime/test/autoep/test_graph_capture.cc	Adds end-to-end test exercising WebGPU plugin EP graph capture + replay via public APIs.

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[Copilot]

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 1 comment.

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Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 1 comment.

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[Copilot]

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[tianleiwu]

Review Summary

Well-structured PR that generalizes the hardcoded EP-specific graph capture logic in InferenceSession into a policy-based, extensible design driven by IExecutionProvider virtual methods. The C API additions are thoroughly documented, version-gated, and defensively validated. The recursion-depth guard in Run() is a valuable safety net.

Highlights

• AreAllComputeNodesAssignedToEpOrCpu() now requires has_node_on_provider, which is a correctness improvement — avoids false positives where no nodes are on the target EP.
• PluginExecutionProvider::IsGraphCaptureEnabled() validation that checks IsGraphCaptured/ReplayGraph are non-null is a valuable defensive measure — without it, ORT would silently hang in the recursive warm-up loop.
• NvTensorRTRTX change to return false from IsGraphCaptureEnabled() is correct: it already returned false from the public IsGraphCaptured() and manages capture internally.
• Excellent API documentation on the four new OrtEp members — exactly the level of detail an out-of-tree EP author needs.

Minor Observations (not blocking)

• CopyTensor API consistency: The new single-tensor CopyTensor(const OrtValue*, OrtValue*, OrtSyncStream*) takes raw pointers while the existing CopyTensors takes const std::vector<Value>& wrappers. Works correctly but inconsistent style.
• CUDA plugin stubs: Since IsGraphCaptureEnabledImpl returns false, the other three stub registrations are dead code. Fine as scaffolding for upcoming work.

Overall: clean, well-tested, ready to merge. Two inline suggestions below.