JavaScript bindings for module API (#12571)

### Summary
The next step for building Executorch for the web is to write JavaScript
bindings for the API.

Added bindidngs that would allow for loading modules and executing
methods in JavaScript, along with a few functions to create tensors and
read its data.

### Test plan
Assuming you already have Emscripten and Node.js version >= 17, you also
need Jest as the testing framework. That can be installed with `npm
install --save-dev jest`

To build and run the tests, run the commands
```
# Build the library and unit tests
bash extension/wasm/build_wasm.sh

# Navigate to the testing output directory
cd cmake-out-wasm/extension/wasm/test/

# Run unit tests
npm test
```

Added CI for unit tests.

Author: Conarnar

.ci/scripts/setup-emscripten.sh

@@ -7,6 +7,13 @@
 
 set -ex
 
+# need version >= 17
+install_node() {
+    curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.3/install.sh | bash
+    source "$HOME/.nvm/nvm.sh"
+    nvm install 22
+}
+
 install_emscripten() {
     git clone https://github.com/emscripten-core/emsdk.git
     pushd emsdk || return
@@ -16,4 +23,5 @@ install_emscripten() {
     popd || return
 }
 
+install_node
 install_emscripten

.github/workflows/pull.yml

@@ -764,6 +764,41 @@ jobs:
         # Test selective build
         PYTHON_EXECUTABLE=python bash examples/wasm/test_build_wasm.sh
 
+  unittest-wasm-bindings:
+    name: unittest-wasm-bindings
+    uses: pytorch/test-infra/.github/workflows/linux_job_v2.yml@main
+    permissions:
+      id-token: write
+      contents: read
+    strategy:
+      fail-fast: false
+    with:
+      runner: linux.2xlarge
+      docker-image: ci-image:executorch-ubuntu-22.04-clang12
+      submodules: 'recursive'
+      ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
+      timeout: 90
+      script: |
+        # The generic Linux job chooses to use base env, not the one setup by the image
+        CONDA_ENV=$(conda env list --json | jq -r ".envs | .[-1]")
+        conda activate "${CONDA_ENV}"
+
+        BUILD_TOOL="cmake"
+        PYTHON_EXECUTABLE=python bash .ci/scripts/setup-linux.sh --build-tool "${BUILD_TOOL}"
+
+        # Install Node.js and Emscripten
+        source .ci/scripts/setup-emscripten.sh
+
+        # Test selective build
+        bash scripts/build_wasm_tests.sh
+
+        # Install Jest
+        cd cmake-out-wasm/extension/wasm/test
+        npm install --save-dev jest
+
+        # Run unit test
+        npm test
+
   unittest-nxp-neutron:
     uses: pytorch/test-infra/.github/workflows/linux_job_v2.yml@main
     permissions:

CMakeLists.txt

@@ -771,6 +771,10 @@ if(EXECUTORCH_BUILD_PYBIND)
   )
 endif()
 
+if(EXECUTORCH_BUILD_WASM)
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/extension/wasm)
+endif()
+
 if(EXECUTORCH_BUILD_EXTENSION_TRAINING)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/extension/training)
   list(APPEND _executorch_extensions extension_training)

extension/wasm/CMakeLists.txt

@@ -0,0 +1,56 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+# Please this file formatted by running:
+# ~~~
+# cmake-format -i CMakeLists.txt
+# ~~~
+
+cmake_minimum_required(VERSION 3.29)
+
+project(executorch_wasm)
+
+if(NOT CMAKE_CXX_STANDARD)
+  set(CMAKE_CXX_STANDARD 17)
+endif()
+
+if(NOT EMSCRIPTEN)
+  message(FATAL_ERROR "Emscripten is required to build this target")
+endif()
+
+# Source root directory for executorch.
+if(NOT EXECUTORCH_ROOT)
+  set(EXECUTORCH_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/../..)
+endif()
+
+include(${EXECUTORCH_ROOT}/tools/cmake/Utils.cmake)
+set(_common_compile_options -Wno-deprecated-declarations -fPIC -Wall -Werror)
+set(_common_include_directories ${EXECUTORCH_ROOT}/..)
+
+set(link_libraries)
+list(
+  APPEND
+  link_libraries
+  embind
+  executorch_core
+  extension_data_loader
+  portable_ops_lib
+  extension_module_static
+  extension_tensor
+  extension_runner_util
+)
+
+add_library(executorch_wasm OBJECT wasm_bindings.cpp)
+
+target_compile_options(executorch_wasm PUBLIC ${_common_compile_options})
+target_include_directories(
+  executorch_wasm PUBLIC ${_common_include_directories}
+)
+target_link_libraries(executorch_wasm PUBLIC ${link_libraries})
+
+if(EXECUTORCH_BUILD_WASM_TESTS)
+  add_subdirectory(test)
+endif()

extension/wasm/test/CMakeLists.txt

@@ -0,0 +1,65 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+# Please this file formatted by running:
+# ~~~
+# cmake-format -i CMakeLists.txt
+# ~~~
+
+set(MODELS_DIR ${CMAKE_CURRENT_BINARY_DIR}/models/)
+
+add_custom_command(
+  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/models/add_mul.pte
+         ${CMAKE_CURRENT_BINARY_DIR}/models/add.pte
+  COMMAND ${CMAKE_COMMAND} -E make_directory "${MODELS_DIR}"
+  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/../../..
+  COMMAND python3 -m examples.portable.scripts.export --model_name="add_mul"
+          --output_dir="${MODELS_DIR}"
+  COMMAND python3 -m examples.portable.scripts.export --model_name="add"
+          --output_dir="${MODELS_DIR}"
+)
+
+add_custom_target(
+  executorch_wasm_test_models DEPENDS ${MODELS_DIR}/add_mul.pte
+                                      ${MODELS_DIR}/add.pte
+)
+
+add_custom_command(
+  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/package.json
+  COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/package.json
+          ${CMAKE_CURRENT_BINARY_DIR}/package.json
+  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/package.json
+  COMMENT "Copying package.json to build output directory"
+)
+
+add_custom_target(
+  executorch_wasm_test_package_json
+  DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/package.json
+)
+
+add_executable(executorch_wasm_tests)
+target_link_libraries(executorch_wasm_tests PUBLIC executorch_wasm)
+target_link_options(
+  executorch_wasm_tests
+  PUBLIC
+  --embed-file
+  "${MODELS_DIR}@/"
+  --post-js
+  ${CMAKE_CURRENT_SOURCE_DIR}/unittests.js
+  -sASSERTIONS=2
+)
+set_target_properties(
+  executorch_wasm_tests PROPERTIES OUTPUT_NAME "executorch_wasm.test"
+)
+set_property(
+  TARGET executorch_wasm_tests
+  APPEND
+  PROPERTY LINK_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/unittests.js
+)
+add_dependencies(
+  executorch_wasm_tests executorch_wasm_test_models
+  executorch_wasm_test_package_json
+)

extension/wasm/test/package.json

@@ -0,0 +1,5 @@
+{
+  "scripts": {
+    "test": "jest"
+  }
+}