[WIP] Make WebGPU EP compatible with EP API by fs-eire · Pull Request #26907 · microsoft/onnxruntime

fs-eire · 2026-01-05T09:27:07Z

Description

This PR makes it possible to build WebGPU EP as an EP API based plugin EP.

Requirements

The goal of this PR is to support both building WebGPU EP as a bundled EP and an EP API based plugin EP. This approach allows:

enabling WebGPU EP as a standalone plugin EP package for WCR usage
graceful transition for WebGPU EP as an native EP for language binding, from the bundled EP to an EP API based plugin EP
keep the existing usage (static library) working (majorly for web)

Design & Implementation

Instead of changing WebGPU EP from a bundled EP to an EP API based plugin EP in one shot, this PR extend WebGPU EP to support building as plugin EP.

add a new folder include/onnxruntime/ep with a bunches of header files. Those files are not WebGPU specific. They are used for:
- include common defines/functions/macros for plugin EP to use
- include a few "adapter" classes that takes C-API objects to simulate ORT internal classes behaviors
- include a few "override" classes that simulate ORT internal classes, but using implementations that only depend on C-API
- include a special base class onnxruntime::ep::Ep to inherit from
These header files allow a compile time "switch" to the different set of types to minimize changes to existing code. Specifically, pch.h is required to be included as PCH to make sure the "override" to take place correctly.
add a new folder onnxruntime/core/providers/webgpu/ep for EP API implementation, specifically:
- api.cc: implements CreateEpFactories and ReleaseEpFactory
- ep.cc ep.h: implement class onnxruntime::webgpu::ep::Ep
- factory.cc factory.h: implement class onnxruntime::webgpu::ep::Factory

Dependencies and Prerequisites

(unmerged changes are included as a part of current PR)

Missing Parts

Allow setting Global/Default EP options

Copilot

Pull request overview

This PR extends WebGPU EP to support building as both a bundled EP (static library) and an EP API-based plugin EP (shared library). The changes introduce a new adapter infrastructure in include/onnxruntime/ep/ that bridges C-API objects to simulate ORT internal class behaviors, enabling compile-time switching between build modes with minimal code changes.

Key changes:

New EP adapter infrastructure with header-only wrapper classes for kernel info, context, registry, and EP interface
WebGPU EP API implementation (api.cc, factory.cc/h, ep.cc/h) in onnxruntime/core/providers/webgpu/ep/
Templated CPU tensor operator base classes to work with both native and adapter OpKernelInfo types
Enhanced C API with KernelInfo_GetOperatorType, KernelInfo_GetSinceVersion, and KernelInfo_GetEp
Test infrastructure updates including example kernel registry changes (Mul kernel renamed to BinaryOp supporting both Add and Mul)

Reviewed changes

Copilot reviewed 75 out of 75 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
include/onnxruntime/ep/*.h	New EP adapter infrastructure headers providing C-API wrappers for kernel registration and execution
onnxruntime/core/providers/webgpu/ep/*	WebGPU EP API implementation for factory, EP instance, and plugin entry points
onnxruntime/core/providers/cpu/tensor/*.h	Templated base classes for tensor ops to support both native and adapter kernel info types
onnxruntime/test/autoep/*	Test updates including BinaryOp generalization and additional test coverage
onnxruntime/core/session/*.cc	Core API additions for kernel info operator type, version, and EP retrieval

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Copilot · 2026-01-06T08:12:57Z

onnxruntime/core/providers/webgpu/tensor/upsample.cc

  InlinedVector<float> scales_array(input_dims.size());
  // opset < 10
-  if (OpKernel::Node().InputDefs().size() == 1) {
+  if (OpKernel::Node().SinceVersion() < 10) {


This check should verify info.node().SinceVersion() < 10 to be consistent with the comment. Checking input count may not be reliable as the input count could vary for other reasons. Use the opset version directly for clarity and correctness.

Copilot · 2026-01-06T08:12:57Z

onnxruntime/core/providers/cpu/tensor/upsamplebase.h

+      if constexpr (std::is_same_v<KernelInfoType, onnxruntime::OpKernelInfo>) {
+        auto x_shape = node.InputDefs()[0]->Shape();
+        if (x_shape != nullptr) {
+          rank = x_shape->dim_size();
+        }
+      } else {
+        int is_const;
+        auto tensor = info.GetKernelInfo().GetTensorConstantInput(0, &is_const);
+        if (is_const) {
+          auto type_and_shape_info = tensor.GetTensorTypeAndShapeInfo();
+          if (type_and_shape_info.HasShape()) {
+            rank = static_cast<int64_t>(type_and_shape_info.GetShape().size());
+          }
+        }
+      }


The constexpr branch at line 223 checks for std::is_same_v<KernelInfoType, onnxruntime::OpKernelInfo> but at line 229, it tries to call methods on info.GetKernelInfo() which suggests that info is expected to be of type onnxruntime::ep::adapter::OpKernelInfo. However, if that's the case, the else branch would execute, and info.GetKernelInfo() would return an Ort::ConstKernelInfo, not an object with a GetTensorConstantInput method. This logic appears inconsistent and may cause compilation or runtime errors.

Copilot · 2026-01-06T08:12:58Z

include/onnxruntime/ep/adapter/tensor_helper.h

+/// </summary>
+inline std::unique_ptr<onnxruntime::Tensor> CreateTensorFromApiValue(const OrtValue* ort_value) {
+  Ort::ConstValue value{ort_value};
+  EP_ENFORCE(value.IsTensor(), "Only tensor OrtValue is supported.");


The macro ORT_ENFORCE depends on exception handling, but when building as a plugin EP, exceptions may not be available or may not behave as expected across DLL boundaries. The code should use return status patterns instead for error handling in the plugin EP build path.

Suggested change

EP_ENFORCE(value.IsTensor(), "Only tensor OrtValue is supported.");

if (!value.IsTensor()) {

// In plugin EP builds, avoid exception-based enforcement and signal failure via nullptr.

return nullptr;

}

Copilot · 2026-01-06T08:12:58Z

onnxruntime/core/providers/webgpu/ep/factory.cc

+    *allocator = new onnxruntime::ep::adapter::Allocator(factory->config_.initializer_allocator);
+  } else {
+    *allocator = new onnxruntime::ep::adapter::Allocator(factory->config_.device_allocator);
+  }


Memory leak: The allocated Allocator instance is never deleted. The caller receives a raw pointer without any indication of ownership. Consider documenting the ownership semantics or using RAII patterns.

Copilot · 2026-01-06T08:12:59Z

onnxruntime/core/providers/webgpu/webgpu_provider_factory.cc

-      if (src_device_id != dst_device_id) {
+      int src_device_id = impl.ep_api.MemoryDevice_GetDeviceId(src_memory_device);
+      int dst_device_id = impl.ep_api.MemoryDevice_GetDeviceId(dst_memory_device);
+      if (src_device_id != impl.context_id_ || dst_device_id != impl.context_id_) {


The device ID check logic appears incorrect. The condition checks if either src_device_id != context_id_ OR dst_device_id != context_id_, which would fail even when copying from the same device. This should use AND (&&) instead of OR (||) to ensure both source and destination match the context.

fs-eire force-pushed the ep-api branch 2 times, most recently from 1ca0d32 to 6873ade Compare January 6, 2026 08:01

fs-eire requested a review from Copilot January 6, 2026 08:09

Copilot started reviewing on behalf of fs-eire January 6, 2026 08:09 View session

fs-eire mentioned this pull request Jan 6, 2026

[EP API] header-only adapter for EP API #26919

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Copilot AI reviewed Jan 6, 2026

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fs-eire force-pushed the ep-api branch 6 times, most recently from 4d451dc to e52d706 Compare January 22, 2026 01:27

fs-eire force-pushed the ep-api branch 6 times, most recently from 9e3419b to 0e58206 Compare February 2, 2026 22:33

fs-eire force-pushed the ep-api branch 3 times, most recently from 3598465 to 902e4f9 Compare February 5, 2026 22:25

[EP API] extract common code for EP API adapter

27301c2

fs-eire force-pushed the ep-api branch from 902e4f9 to 4a5e066 Compare February 6, 2026 01:13

fs-eire added 2 commits February 6, 2026 21:49

[EP API] header-only adapter for EP API

629e4ec

Implement EP API for WebGPU EP

6333b00

fs-eire force-pushed the ep-api branch from 4a5e066 to 6333b00 Compare February 7, 2026 05:50

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[WIP] Make WebGPU EP compatible with EP API#26907

[WIP] Make WebGPU EP compatible with EP API#26907
fs-eire wants to merge 3 commits intomicrosoft:mainfrom
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fs-eire commented Jan 5, 2026 •

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-  EP_ENFORCE(value.IsTensor(), "Only tensor OrtValue is supported.");
+  if (!value.IsTensor()) {
+    // In plugin EP builds, avoid exception-based enforcement and signal failure via nullptr.
+    return nullptr;
+  }

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Description

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Design & Implementation

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fs-eire commented Jan 5, 2026 •

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