[js/webgpu] following up for JSEP/WebGPU code cleanup (#15666)

### Description
This PR resolves a part of non-critical comments from code review
comments in #14579.

- use `USE_JSEP` instead of `USE_JS` in build definition to make it less
ambiguous
- remove unused util functions from util.ts
- fix transpose.h
- other misc fixes

cmake/CMakeLists.txt

@@ -68,7 +68,7 @@ option(onnxruntime_USE_QNN "Build with QNN support" OFF)
 option(onnxruntime_USE_SNPE "Build with SNPE support" OFF)
 option(onnxruntime_USE_RKNPU "Build with RKNPU support" OFF)
 option(onnxruntime_USE_DNNL "Build with DNNL support" OFF)
-option(onnxruntime_USE_JS "Build with JavaScript implemented kernels support" OFF)
+option(onnxruntime_USE_JSEP "Build with JavaScript implemented kernels support" OFF)
 option(onnxruntime_BUILD_UNIT_TESTS "Build ONNXRuntime unit tests" ON)
 option(onnxruntime_BUILD_CSHARP "Build C# library" OFF)
 option(onnxruntime_BUILD_OBJC "Build Objective-C library" OFF)
@@ -662,9 +662,9 @@ if (onnxruntime_USE_NNAPI_BUILTIN)
     list(APPEND ORT_PROVIDER_CMAKE_FLAGS -Donnxruntime_USE_NNAPI_BUILTIN=1)
     list(APPEND ONNXRUNTIME_PROVIDER_NAMES nnapi)
 endif()
-if (onnxruntime_USE_JS)
-    list(APPEND ORT_PROVIDER_FLAGS -DUSE_JS=1)
-    list(APPEND ORT_PROVIDER_CMAKE_FLAGS -Donnxruntime_USE_JS=1)
+if (onnxruntime_USE_JSEP)
+    list(APPEND ORT_PROVIDER_FLAGS -DUSE_JSEP=1)
+    list(APPEND ORT_PROVIDER_CMAKE_FLAGS -Donnxruntime_USE_JSEP=1)
     list(APPEND ONNXRUNTIME_PROVIDER_NAMES js)
 endif()
 if (onnxruntime_USE_QNN)

cmake/onnxruntime_providers.cmake

@@ -114,7 +114,7 @@ endif()
 if(onnxruntime_USE_NNAPI_BUILTIN)
   set(PROVIDERS_NNAPI onnxruntime_providers_nnapi)
 endif()
-if(onnxruntime_USE_JS)
+if(onnxruntime_USE_JSEP)
   set(PROVIDERS_JS onnxruntime_providers_js)
 endif()
 if(onnxruntime_USE_QNN)
@@ -1067,8 +1067,8 @@ if (onnxruntime_USE_NNAPI_BUILTIN)
   endif()
 endif()
 
-if (onnxruntime_USE_JS)
-  add_compile_definitions(USE_JS=1)
+if (onnxruntime_USE_JSEP)
+  add_compile_definitions(USE_JSEP=1)
 
   file(GLOB_RECURSE onnxruntime_providers_js_cc_srcs
     "${ONNXRUNTIME_ROOT}/core/providers/js/*.h"

cmake/onnxruntime_unittests.cmake

@@ -504,7 +504,7 @@ if(onnxruntime_USE_NNAPI_BUILTIN)
   list(APPEND onnxruntime_test_providers_dependencies onnxruntime_providers_nnapi)
 endif()
 
-if(onnxruntime_USE_JS)
+if(onnxruntime_USE_JSEP)
   list(APPEND onnxruntime_test_providers_dependencies onnxruntime_providers_js)
 endif()
 
@@ -609,7 +609,7 @@ if(onnxruntime_USE_NNAPI_BUILTIN)
   list(APPEND onnxruntime_test_providers_libs onnxruntime_providers_nnapi)
 endif()
 
-if(onnxruntime_USE_JS)
+if(onnxruntime_USE_JSEP)
   list(APPEND onnxruntime_test_framework_src_patterns  ${TEST_SRC_DIR}/providers/js/*)
   list(APPEND onnxruntime_test_framework_libs onnxruntime_providers_js)
   list(APPEND onnxruntime_test_providers_dependencies onnxruntime_providers_js)
@@ -851,7 +851,7 @@ if (onnxruntime_BUILD_WEBASSEMBLY)
   if (onnxruntime_ENABLE_WEBASSEMBLY_THREADS)
     set_property(TARGET onnxruntime_test_all APPEND_STRING PROPERTY LINK_FLAGS " -s USE_PTHREADS=1 -s PROXY_TO_PTHREAD=1")
   endif()
-  if (onnxruntime_USE_JS)
+  if (onnxruntime_USE_JSEP)
     set_property(TARGET onnxruntime_test_all APPEND_STRING PROPERTY LINK_FLAGS " --pre-js \"${ONNXRUNTIME_ROOT}/wasm/js_internal_api.js\"")
   endif()
 endif()

cmake/onnxruntime_webassembly.cmake

@@ -199,7 +199,7 @@ else()
   endif()
 
   set(EXPORTED_RUNTIME_METHODS "['stackAlloc','stackRestore','stackSave','UTF8ToString','stringToUTF8','lengthBytesUTF8']")
-  if (onnxruntime_USE_JS)
+  if (onnxruntime_USE_JSEP)
     set(EXPORTED_FUNCTIONS "_malloc,_free,_JsepOutput")
   else()
     set(EXPORTED_FUNCTIONS "_malloc,_free")
@@ -219,12 +219,12 @@ else()
     --no-entry
   )
 
-  if (onnxruntime_USE_JS)
+  if (onnxruntime_USE_JSEP)
     # NOTE: "-s ASYNCIFY=1" is required for JSEP to work with WebGPU
     #       This flag allows async functions to be called from sync functions, in the cost of binary size and
     #       build time. See https://emscripten.org/docs/porting/asyncify.html for more details.
 
-    target_compile_definitions(onnxruntime_webassembly PRIVATE USE_JS=1)
+    target_compile_definitions(onnxruntime_webassembly PRIVATE USE_JSEP=1)
     target_link_options(onnxruntime_webassembly PRIVATE
       --pre-js "${ONNXRUNTIME_ROOT}/wasm/js_internal_api.js"
       "SHELL:-s ASYNCIFY=1"

js/web/lib/wasm/jsep/backend-webgpu.ts

@@ -144,8 +144,10 @@ export class WebGpuBackend {
   }
 
   dispose(): void {
-    // TODO: uninitialization
-    // this.glContext.dispose();
+    // currently, we do not do anything in this function. In all known use cases, we don't have the requirement to
+    // actually dispose the WebGpuBackend instance, because it's always used as a singleton.
+    //
+    // revisit this place if we get real requirement to dispose the instance.
   }
 
   getCommandEncoder(): GPUCommandEncoder {

js/web/lib/wasm/jsep/init.ts

@@ -29,7 +29,7 @@ class TensorViewImpl implements TensorView {
   }
 }
 
-class OpKernelContext implements ComputeContext {
+class ComputeContextImpl implements ComputeContext {
   readonly opKernelContext: number;
   readonly inputs: readonly TensorView[];
   get customData(): {[key: string]: unknown} {
@@ -142,7 +142,7 @@ export const init = async(module: OrtWasmModule): Promise<void> => {
         // jsepRun
         (kernel: number, contextDataOffset: number) => {
           LOG_DEBUG('verbose', () => `[WebGPU] jsepRun: kernel=${kernel}, contextDataOffset=${contextDataOffset}`);
-          const context = new OpKernelContext(module, backend, contextDataOffset);
+          const context = new ComputeContextImpl(module, backend, contextDataOffset);
           return backend.computeKernel(kernel, context);
         });
   }