firefox-main/dom/base/test/test_wasm_offthread_compile.html (file symbol)

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Test Info: Warnings

  • This test gets skipped with pattern: os == 'linux' && os_version == '24.04' && arch == 'x86_64' && debug && verify-standalone OR !nightly_build
  • Manifest: dom/base/test/mochitest.toml
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test for off-main-thread compilation of source phase wasm modules.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script type="application/javascript">
// Each import needs a distinct URL, otherwise the module map returns the
// already-compiled module and the ScriptLoader is never consulted.
let counter = 0;
function moduleUrl() {
return `./file_wasm_offthread_module.sjs?n=${counter++}`;
}
// Source phase imports the given module and returns both the module and the
// compilation path the ScriptLoader reported for it.
async function importAndTrace(specifier) {
// The notification reports the resolved URL, which has no "./" prefix.
const url = specifier.replace(/^\.\//, "");
let resolveTrace;
const trace = new Promise(resolve => { resolveTrace = resolve; });
function observer(subject, topic, data) {
const param = {};
for (const line of data.split("\n")) {
const m = line.match(/^([^:]+):(.+)/);
if (m) {
param[m[1]] = m[2];
}
}
// Other scripts on the page emit notifications too; only watch the
// module this call is importing.
if (!param.url || !param.url.includes(url)) {
return;
}
if (param.event == "compile:off thread" ||
param.event == "compile:main thread") {
resolveTrace(param.event);
}
}
SpecialPowers.Services.obs.addObserver(observer, "ScriptLoaderTest");
try {
const mod = await import.source(specifier);
return { mod, path: await trace };
} finally {
SpecialPowers.Services.obs.removeObserver(observer, "ScriptLoaderTest");
}
}
// Setting dom.expose_test_interfaces causes the ScriptLoader to fire the
// notifications this test observes.
//
// The wasm ESM integration and source phase import prefs are required for
// `import source` to be available at all.
const BASE_PREFS = [
['dom.expose_test_interfaces', true],
['javascript.options.experimental.wasm_esm_integration', true],
['javascript.options.experimental.source_phase_imports', true],
];
promise_test(async function() {
await SpecialPowers.pushPrefEnv({set: [
...BASE_PREFS,
['javascript.options.parallel_parsing', true],
]});
const url = moduleUrl();
const { mod, path } = await importAndTrace(url);
assert_equals(path, "compile:off thread",
"a module over the size threshold compiles off-thread");
assert_true(mod instanceof WebAssembly.Module,
"source phase import produces a WebAssembly.Module");
const instance = await WebAssembly.instantiate(mod);
assert_equals(instance.exports.f0(2, 3), 5,
"an off-thread compiled function runs correctly");
}, "A large source phase wasm module is compiled off the main thread");
// The negative control: without it, the test above would still pass if the
// trace were emitted unconditionally.
promise_test(async function() {
await SpecialPowers.pushPrefEnv({set: [
...BASE_PREFS,
['javascript.options.parallel_parsing', false],
]});
const url = moduleUrl();
const { mod, path } = await importAndTrace(url);
assert_equals(path, "compile:main thread",
"disabling parallel parsing falls back to the main thread");
const instance = await WebAssembly.instantiate(mod);
assert_equals(instance.exports.f0(2, 3), 5,
"a main-thread compiled function runs correctly");
}, "Source phase wasm compilation falls back to the main thread");
done();
</script>
</head>
<body>
</body>
</html>