From 17d53842e129083b65154727bf244eb9ce209f33 Mon Sep 17 00:00:00 2001
From: Yulong Wang <7679871+fs-eire@users.noreply.github.com>
Date: Tue, 3 Dec 2024 19:25:22 -0800
Subject: [PATCH] allow specify a custom local source path for Dawn (#22999)

### Description

Allows to build ONNX Runtime with a custom local path of Dawn's source
code.

Usage:
```sh
build --use_webgpu --cmake_extra_defines "onnxruntime_CUSTOM_DAWN_SRC_PATH=C:/src/dawn"

```
---
 cmake/CMakeLists.txt                          |  1 +
 .../external/onnxruntime_external_deps.cmake  | 23 ++++++++++++++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 70ac62954ad6d..7710ab2f4cac7 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -148,6 +148,7 @@ option(onnxruntime_USE_XNNPACK "Build with XNNPACK support. Provides an alternat
 option(onnxruntime_USE_WEBNN "Build with WebNN support. Enable hardware acceleration in web browsers." OFF)
 option(onnxruntime_USE_WEBGPU "Build with WebGPU support. Enable WebGPU via C/C++ interface." OFF)
 option(onnxruntime_USE_EXTERNAL_DAWN "Build with treating Dawn as external dependency. Will not link Dawn at build time." OFF)
+option(onnxruntime_CUSTOM_DAWN_SRC_PATH "Path to custom Dawn src dir.")
 
 # Options related to reducing the binary size produced by the build
 # XNNPACK EP requires the internal NHWC contrib ops to be available, so this option must be OFF when onnxruntime_USE_XNNPACK is ON
diff --git a/cmake/external/onnxruntime_external_deps.cmake b/cmake/external/onnxruntime_external_deps.cmake
index d9e833a2d8cd4..5e619af619f18 100644
--- a/cmake/external/onnxruntime_external_deps.cmake
+++ b/cmake/external/onnxruntime_external_deps.cmake
@@ -615,12 +615,23 @@ if (onnxruntime_USE_COREML)
 endif()
 
 if (onnxruntime_USE_WEBGPU)
-  FetchContent_Declare(
-    dawn
-    URL ${DEP_URL_dawn}
-    URL_HASH SHA1=${DEP_SHA1_dawn}
-    PATCH_COMMAND ${Patch_EXECUTABLE} --binary --ignore-whitespace -p1 < ${PROJECT_SOURCE_DIR}/patches/dawn/dawn.patch
-  )
+  if (onnxruntime_CUSTOM_DAWN_SRC_PATH)
+    # use the custom dawn source path if provided
+    #
+    # specified as:
+    # build.py --use_webgpu --cmake_extra_defines "onnxruntime_CUSTOM_DAWN_SRC_PATH=<PATH_TO_DAWN_SRC_ROOT>"
+    FetchContent_Declare(
+      dawn
+      SOURCE_DIR ${onnxruntime_CUSTOM_DAWN_SRC_PATH}
+    )
+  else()
+    FetchContent_Declare(
+      dawn
+      URL ${DEP_URL_dawn}
+      URL_HASH SHA1=${DEP_SHA1_dawn}
+      PATCH_COMMAND ${Patch_EXECUTABLE} --binary --ignore-whitespace -p1 < ${PROJECT_SOURCE_DIR}/patches/dawn/dawn.patch
+    )
+  endif()
 
   # use dawn::dawn_native and dawn::dawn_proc instead of the monolithic dawn::webgpu_dawn to minimize binary size
   set(DAWN_BUILD_MONOLITHIC_LIBRARY OFF CACHE BOOL "" FORCE)