Add Box2D workload compiled with J2CL/J2Wasm to WasmGC

JetStreamDriver.js

@@ -2521,6 +2521,19 @@ let BENCHMARKS = [
         worstCaseCount: 2,
         tags: ["Default", "Wasm", "dotnet"],
     }),
+    // J2CL
+    new AsyncBenchmark({
+        name: "j2cl-box2d-wasm",
+        files: [
+            "./wasm/j2cl-box2d/benchmark.js",
+            "./wasm/j2cl-box2d/build/Box2dBenchmark_j2wasm_entry.js",
+        ],
+        preload: {
+            wasmBinary: "./wasm/j2cl-box2d/build/Box2dBenchmark_j2wasm_binary.wasm",
+        },
+        iterations: 40,
+        tags: ["Default", "Wasm"],
+    }),
 ];
 
 

wasm/j2cl-box2d/.gitignore

@@ -0,0 +1 @@
+/j2cl/

wasm/j2cl-box2d/add-fixed-run-count-api.patch

@@ -0,0 +1,77 @@
+diff --git a/benchmarking/java/com/google/j2cl/benchmarking/benchmarks.bzl b/benchmarking/java/com/google/j2cl/benchmarking/benchmarks.bzl
+index 04c4c72007..601cafdcb5 100644
+--- a/benchmarking/java/com/google/j2cl/benchmarking/benchmarks.bzl
++++ b/benchmarking/java/com/google/j2cl/benchmarking/benchmarks.bzl
+@@ -95,6 +95,7 @@ def benchmark(name, deps = [], data = [], jvm_only = False, perfgate_test_tags =
+             "%s.%sLauncher#execute" % (benchmark_java_package, name),
+             "%s.%sLauncher#prepareForRunOnce" % (benchmark_java_package, name),
+             "%s.%sLauncher#runOnce" % (benchmark_java_package, name),
++            "%s.%sLauncher#runFixedCount" % (benchmark_java_package, name),
+         ],
+     )
+
+diff --git a/benchmarking/java/com/google/j2cl/benchmarking/templates.bzl b/benchmarking/java/com/google/j2cl/benchmarking/templates.bzl
+index b75b8567dd..8e083f9aa2 100644
+--- a/benchmarking/java/com/google/j2cl/benchmarking/templates.bzl
++++ b/benchmarking/java/com/google/j2cl/benchmarking/templates.bzl
+@@ -34,6 +34,17 @@ public class #benchmarkName#Launcher {
+     benchmark.run();
+     benchmark = null; // Make sure it is only executed once.
+   }
++
++  public static void runFixedCount(int count) {
++    AbstractBenchmark bench = new #benchmarkName#();
++    bench.setupOneTime();
++    for (int i = 0; i < count; i++) {
++      bench.setup();
++      bench.run();
++      bench.tearDown();
++    }
++    bench.tearDownOneTime();
++  }
+ }
+ """
+
+@@ -54,7 +65,12 @@ goog.module('#benchmarkName#_launcher')
+
+ const j2wasm = goog.require('#wasm_module_name#');
+
+-if (typeof read == 'undefined') {
++if (typeof isJetStreamDriver !== 'undefined') {
++  // Running as a JetStream benchmark; expose "instantiateAsync" to JetStream driver.
++  goog.global['instantiateAsync'] = async function(buffer) {
++    return j2wasm.instantiate(await j2wasm.compile(buffer));
++  }
++} else if (typeof read == 'undefined') {
+   // Running on browser, fetch the file from server.
+   j2wasm.instantiateStreaming("#wasm_url#")
+       .then((instance) => Object.assign(goog.global, instance.exports));
+diff --git a/build_defs/internal_do_not_use/j2wasm_application.bzl b/build_defs/internal_do_not_use/j2wasm_application.bzl
+index 36d3abaacd..211319deb9 100644
+--- a/build_defs/internal_do_not_use/j2wasm_application.bzl
++++ b/build_defs/internal_do_not_use/j2wasm_application.bzl
+@@ -50,6 +50,15 @@ async function compileStreaming(urlOrResponse) {
+   return WebAssembly.compileStreaming(response, options);
+ }
+
++/**
++ * @param {!BufferSource} moduleBuffer
++ * @return {!Promise<!WebAssembly.Module>}
++ * @suppress {checkTypes} Externs are missing options parameter (phase 2)
++ */
++async function compile(moduleBuffer) {
++  return WebAssembly.compile(moduleBuffer, options);
++}
++
+ /**
+  * @param {!WebAssembly.Module} module
+  * @return {!Promise<!WebAssembly.Instance>}
+@@ -91,7 +100,7 @@ function prepareImports(module) {
+   return imports;
+ }
+
+-exports = {compileStreaming, instantiate, instantiateStreaming, instantiateBlocking};
++exports = {compile, compileStreaming, instantiate, instantiateStreaming, instantiateBlocking};
+ """
+
+ def _impl_j2wasm_application(ctx):

wasm/j2cl-box2d/benchmark.js

@@ -0,0 +1,39 @@
+// Copyright 2025 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Hook into the J2Cl application runner, enables explicit instantiation via `instantiateAsync` below.
+const isJetStreamDriver = true;
+
+// Polyfills for shells. See j2cl/bazel-j2cl/benchmarking/java/com/google/j2cl/benchmarking/templates.bzl
+class TextDecoder {
+  decode(buffer) {
+    return String.fromCharCode.apply(null, new Uint8Array(buffer));
+  }
+}
+// The following polyfills are just required for imports but not actually used.
+function unused_import() {
+  throw new Error('not supported, should be an unused import');
+}
+var atob = unused_import;
+var btoa = unused_import;
+var gc = unused_import;
+
+class Benchmark {
+  wasmBinary;
+  wasmInstanceExports;
+
+  async init() {
+    this.wasmBinary = await JetStream.getBinary(JetStream.preload.wasmBinary);
+  }
+
+  async runIteration() {
+    // Compile once in the first iteration.`
+    if (!this.wasmInstanceExports) {
+      this.wasmInstanceExports = (await instantiateAsync(this.wasmBinary)).exports;
+    }
+
+    const internalIterations = 5;
+    this.wasmInstanceExports.runFixedCount(internalIterations);
+  }
+}

wasm/j2cl-box2d/build.log

@@ -0,0 +1,5 @@
+Built on 2025-08-20 17:36:29+02:00
+Cloning into 'j2cl'...
+fbbe1e6db2 [J2KT] Remove dangling readable files which were added by accident.
+Copying generated files into build/
+Build success

wasm/j2cl-box2d/build.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+set -eo pipefail
+
+# Cleanup old files.
+rm -rf build/
+rm -rf j2cl/
+
+BUILD_LOG="$(realpath build.log)"
+echo -e "Built on $(date --rfc-3339=seconds)" | tee "$BUILD_LOG"
+
+# Build the benchmark from source.
+git clone git@github.com:google/j2cl.git |& tee -a "$BUILD_LOG"
+pushd j2cl/
+git log -1 --oneline | tee -a "$BUILD_LOG"
+git apply ../add-fixed-run-count-api.patch | tee -a "$BUILD_LOG"
+BUILD_SRC_DIR="benchmarking/java/com/google/j2cl/benchmarks/octane/"
+pushd "$BUILD_SRC_DIR"
+bazel build //benchmarking/java/com/google/j2cl/benchmarks/octane:Box2dBenchmark_local-j2wasm-v8
+popd
+popd
+
+echo "Copying generated files into build/" | tee -a "$BUILD_LOG"
+mkdir -p build/ | tee -a "$BUILD_LOG"
+BUILD_OUT_DIR="j2cl/bazel-bin/$BUILD_SRC_DIR"
+cp $BUILD_OUT_DIR/Box2dBenchmark_j2wasm_entry.js build/ | tee -a "$BUILD_LOG"
+# FIXME: Remove this workaround, once Safari/JSC implements JS-string builtins.
+# Since these imports/builtins are never called in the workload, they should not have any effect on runtime.
+sed -i 's/imports:/"wasm:js-string":{fromCharCodeArray:unused_import,concat:unused_import,equals:unused_import,compare:unused_import,length:unused_import,charCodeAt:unused_import,substring:unused_import},imports:/g' build/Box2dBenchmark_j2wasm_entry.js
+cp $BUILD_OUT_DIR/Box2dBenchmark_j2wasm_binary.wasm build/ | tee -a "$BUILD_LOG"
+cp $BUILD_OUT_DIR/Box2dBenchmark_j2wasm_binary.binaryen.symbolmap build/ | tee -a "$BUILD_LOG"
+echo "Build success" | tee -a "$BUILD_LOG"