Support threads and threads+SIMD in WebP2

codecs/avif/enc/avif_enc_mt.d.ts

@@ -1,2 +1 @@
-export * from './avif_enc';
 export { default } from './avif_enc';

codecs/wp2/Makefile

@@ -1,20 +1,30 @@
 CODEC_URL = https://chromium.googlesource.com/codecs/libwebp2/+archive/c90b5b476004c9a98731ae1c175cebab5de50fbf.tar.gz
 CODEC_DIR = node_modules/wp2
-CODEC_BUILD_DIR := $(CODEC_DIR)/.build
+CODEC_BUILD_ROOT := $(CODEC_DIR)/build
-CODEC_OUT := $(CODEC_BUILD_DIR)/libwebp2.a
+CODEC_BASELINE_BUILD_DIR := $(CODEC_BUILD_ROOT)/baseline
+CODEC_MT_BUILD_DIR := $(CODEC_BUILD_ROOT)/mt
+CODEC_MT_SIMD_BUILD_DIR := $(CODEC_BUILD_ROOT)/mt-simd
 
-OUT_JS = enc/wp2_enc.js dec/wp2_dec.js
+OUT_JS = enc/wp2_enc.js enc/wp2_enc_mt.js enc/wp2_enc_mt_simd.js dec/wp2_dec.js
-OUT_WASM = $(OUT_JS:.js=.wasm)
+OUT_WASM := $(OUT_JS:.js=.wasm)
+OUT_WORKER := $(OUT_JS:.js=.worker.js)
 
 .PHONY: all clean
 
 all: $(OUT_JS)
 
-%.js: %.cpp $(CODEC_OUT)
+# Define dependencies for all variations of build artifacts.
-	$(CXX) \
+$(filter enc/%,$(OUT_JS)): enc/wp2_enc.o
-		-I $(CODEC_DIR) \
+$(filter dec/%,$(OUT_JS)): dec/wp2_dec.o
-		${CXXFLAGS} \
+enc/wp2_enc.js dec/wp2_dec.js: $(CODEC_BASELINE_BUILD_DIR)/libwebp2.a
-		${LDFLAGS} \
+enc/wp2_enc_mt.js: $(CODEC_MT_BUILD_DIR)/libwebp2.a
+enc/wp2_enc_mt_simd.js: $(CODEC_MT_SIMD_BUILD_DIR)/libwebp2.a
+# Link multithreaded builds with -pthread.
+enc/wp2_enc_mt.js enc/wp2_enc_mt_simd.js: LDFLAGS+=-pthread
+
+$(OUT_JS):
+	$(LD) \
+		$(LDFLAGS) \
 		--bind \
 		--closure 1 \
 		-s ALLOW_MEMORY_GROWTH=1 \
@@ -26,25 +36,43 @@ all: $(OUT_JS)
 		-o $@ \
 		$+
 
-$(CODEC_OUT): $(CODEC_BUILD_DIR)/Makefile
+%.o: %.cpp $(CODEC_DIR)/CMakeLists.txt
-	cd $(CODEC_BUILD_DIR) && \
+	$(CXX) \
-	$(MAKE)
+		$(CXXFLAGS) \
+		-I $(CODEC_DIR) \
+		-o $@ \
+		$<
 
-$(CODEC_BUILD_DIR)/Makefile: $(CODEC_DIR)/CMakeLists.txt
+%/libwebp2.a: %/Makefile
-	mkdir -p $(CODEC_BUILD_DIR)
+	$(MAKE) -C $(@D)
-	cd $(CODEC_BUILD_DIR) && \
+
+# Disable SIMD for non-SIMD builds.
+$(CODEC_BASELINE_BUILD_DIR)/Makefile $(CODEC_MT_BUILD_DIR)/Makefile: CMAKE_FLAGS+=-DWP2_ENABLE_SIMD=0
+
+# Disable threads for the single-threaded build.
+$(CODEC_BASELINE_BUILD_DIR)/Makefile: CMAKE_FLAGS+=-DCMAKE_DISABLE_FIND_PACKAGE_Threads=1
+
+# The line below should be unnecessary in the future.
+# See https://github.com/emscripten-core/emscripten/issues/12714 for -msimd128.
+# See https://github.com/emscripten-core/emscripten/issues/12746 for -msse4.2.
+$(CODEC_MT_SIMD_BUILD_DIR)/Makefile: CXXFLAGS+=-msimd128 -msse4.2
+
+%/Makefile: $(CODEC_DIR)/CMakeLists.txt
 	emcmake cmake \
-		-DWP2_ENABLE_SIMD=0 \
+		$(CMAKE_FLAGS) \
 		-DWP2_BUILD_TESTS=0 \
 		-DWP2_ENABLE_TESTS=0 \
 		-DWP2_BUILD_EXAMPLES=0 \
 		-DWP2_BUILD_EXTRAS=0 \
-		../
+		-B $(@D) \
+		$(<D)
 
 $(CODEC_DIR)/CMakeLists.txt:
 	mkdir -p $(CODEC_DIR)
 	curl -sL $(CODEC_URL) | tar xz -C $(CODEC_DIR)
 
 clean:
-	$(RM) $(OUT_JS) $(OUT_WASM)
+	$(RM) $(OUT_JS) $(OUT_WASM) $(OUT_WORKER)
-	$(MAKE) -C $(CODEC_BUILD_DIR) clean
+	$(MAKE) -C $(CODEC_BASELINE_BUILD_DIR) clean
+	$(MAKE) -C $(CODEC_MT_BUILD_DIR) clean
+	$(MAKE) -C $(CODEC_MT_SIMD_BUILD_DIR) clean

codecs/wp2/enc/wp2_enc.cpp

@@ -1,5 +1,6 @@
 #include <emscripten/bind.h>
 #include <emscripten/val.h>
+#include <emscripten/threading.h>
 #include <cstdio>
 #include "src/wp2/encode.h"
 
@@ -42,6 +43,7 @@ val encode(std::string image_in, int image_width, int image_height, WP2Options o
   }
 
   WP2::MemoryWriter memory_writer;
+  config.thread_level = emscripten_num_logical_cores() - 1;
   status = WP2::Encode(src, &memory_writer, config);
   if (status != WP2_STATUS_OK) {
     return val::null();

src/features/encoders/avif/worker/avifEncode.ts

@@ -44,6 +44,5 @@ export default async function encode(
 
   if (!result) throw new Error('Encoding error');
 
-  // wasm can’t run on SharedArrayBuffers, so we hard-cast to ArrayBuffer.
+  return result.buffer;
-  return result.buffer as ArrayBuffer;
 }

src/features/encoders/wp2/worker/wp2Encode.ts

@@ -10,24 +10,56 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import wp2Encoder, { WP2Module } from 'codecs/wp2/enc/wp2_enc';
+import type { WP2Module } from 'codecs/wp2/enc/wp2_enc';
-import wasmUrl from 'url:codecs/wp2/enc/wp2_enc.wasm';
-import { initEmscriptenModule } from 'features/worker-utils';
 import type { EncodeOptions } from '../shared/meta';
 
+import { initEmscriptenModule } from 'features/worker-utils';
+import { threads, simd } from 'wasm-feature-detect';
+
+import wasmUrl from 'url:codecs/wp2/enc/wp2_enc.wasm';
+
+import wasmUrlWithMT from 'url:codecs/wp2/enc/wp2_enc_mt.wasm';
+import workerUrl from 'omt:codecs/wp2/enc/wp2_enc_mt.worker.js';
+
+import wasmUrlWithMTAndSIMD from 'url:codecs/wp2/enc/wp2_enc_mt_simd.wasm';
+import workerUrlWithSIMD from 'omt:codecs/wp2/enc/wp2_enc_mt_simd.worker.js';
+
 let emscriptenModule: Promise<WP2Module>;
 
+async function init() {
+  if (await threads()) {
+    if (await simd()) {
+      const wp2Encoder = await import('codecs/wp2/enc/wp2_enc_mt_simd');
+      return initEmscriptenModule(
+        wp2Encoder.default,
+        wasmUrlWithMTAndSIMD,
+        workerUrlWithSIMD,
+      );
+    }
+    const wp2Encoder = await import('codecs/wp2/enc/wp2_enc_mt');
+    return initEmscriptenModule(
+      wp2Encoder.default,
+      wasmUrlWithMT,
+      workerUrl,
+    );
+  }
+  const wp2Encoder = await import('codecs/wp2/enc/wp2_enc');
+  return initEmscriptenModule(
+    wp2Encoder.default,
+    wasmUrl,
+  );
+}
+
 export default async function encode(
   data: ImageData,
   options: EncodeOptions,
 ): Promise<ArrayBuffer> {
-  if (!emscriptenModule) {
+  if (!emscriptenModule) emscriptenModule = init();
-    emscriptenModule = initEmscriptenModule(wp2Encoder, wasmUrl);
-  }
 
   const module = await emscriptenModule;
   const result = module.encode(data.data, data.width, data.height, options);
+
   if (!result) throw new Error('Encoding error.');
-  // wasm can’t run on SharedArrayBuffers, so we hard-cast to ArrayBuffer.
+
-  return result.buffer as ArrayBuffer;
+  return result.buffer;
 }