Add Webassembly build

.github/workflows/build.yaml

@@ -223,10 +223,49 @@ jobs:
         name: emlearn-micropython-build-macos
         path: dist
 
+  build-webassembly:
+    runs-on: ubuntu-latest
+    env:
+      MPY_DIR: ./micropython
+      MICROPYTHON_BIN: ./micropython/ports/unix/build-nomodules/micropython
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: true
+    - name: Install OS dependencies
+      run: sudo add-apt-repository universe
+    - uses: actions/setup-python@v5
+      with:
+        python-version: '3.10'
+    - uses: actions/checkout@v4
+      with:
+        repository: jonnor/micropython
+        path: micropython
+        ref: webassembly-extra-cflags
+    - name: Install Python dependencies
+      run: pip install -r requirements.txt
+    - name: Setup MicroPython
+      working-directory: micropython
+      run: |
+        npm install terser
+        git clone https://github.com/emscripten-core/emsdk.git
+        (cd emsdk && ./emsdk install 4.0.21 && ./emsdk activate 4.0.21)
+        make -C mpy-cross CFLAGS_EXTRA=-Wno-error
+    - name: Build Webassembly
+      run: |
+        source ${MPY_DIR}/emsdk/emsdk_env.sh
+        make -C ${MPY_DIR}/ports/webassembly submodules
+        make webassembly V=1
+    - name: Archive dist artifacts
+      uses: actions/upload-artifact@v4
+      with:
+        name: emlearn-micropython-build-webassembly
+        path: dist
+
   deploy-pages:
     permissions:
       contents: write
-    needs: [build-linux, build-arm, build-esp32, build-macos, build-riscv]
+    needs: [build-linux, build-arm, build-esp32, build-macos, build-riscv, build-webassembly]
     runs-on: ubuntu-latest
 
     steps:

Makefile

@@ -27,7 +27,7 @@ PORT_BUILD_DIR=$(MPY_DIR)/ports/$(PORT)/build-$(BOARD)
 PORT_DIST_DIR=./dist/ports/$(PORT)/$(BOARD)
 
 UNIX_MICROPYTHON = ./dist/ports/unix/micropython
-
+WEBASSEMBLY_MICROPYTHON = ./dist/ports/webassembly/micropython.mjs
 
 # List of modules
 MODULES = emlearn_trees \
@@ -72,6 +72,17 @@ $(UNIX_MICROPYTHON): $(PORT_DIR)
 
 unix: $(UNIX_MICROPYTHON)
 
+$(WEBASSEMBLY_MICROPYTHON): $(PORT_DIR)
+	emcc --version
+	mkdir -p $(PORT_DIR)/../webassembly
+	make -C $(MPY_DIR)/ports/webassembly VARIANT=standard V=1 USER_C_MODULES=$(C_MODULES_SRC_PATH) FROZEN_MANIFEST=$(MANIFEST_PATH) CFLAGS_EXTRA="-Wno-unused-function -Wno-unused-function ${CFLAGS_EXTRA}" -j4
+	cp $(MPY_DIR)/ports/webassembly/build-standard/micropython.mjs $@
+	cp $(MPY_DIR)/ports/webassembly/build-standard/micropython.wasm dist/ports/webassembly/
+
+
+webassembly: $(WEBASSEMBLY_MICROPYTHON)
+
+
 check_unix: $(UNIX_MICROPYTHON)
 	$(UNIX_MICROPYTHON) tests/test_all.py test_iir,test_fft,test_arrayutils
 	# TODO: enable more modules