1 files changed, 72 insertions, 0 deletions
diff --git a/js/src/jsapi-tests/testSharedImmutableStringsCache.cpp b/js/src/jsapi-tests/testSharedImmutableStringsCache.cpp
new file mode 100644
index 0000000000..461bd6b21d
--- /dev/null
+++ b/js/src/jsapi-tests/testSharedImmutableStringsCache.cpp
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/IntegerRange.h"
+
+#include "js/Vector.h"
+#include "jsapi-tests/tests.h"
+#include "threading/Thread.h"
+#include "util/Text.h"
+#include "vm/SharedImmutableStringsCache.h"
+
+const int NUM_THREADS = 256;
+const int NUM_ITERATIONS = 256;
+
+const int NUM_STRINGS = 4;
+const char16_t* const STRINGS[NUM_STRINGS] = {u"uno", u"dos", u"tres",
+                                              u"quattro"};
+
+struct CacheAndIndex {
+  js::SharedImmutableStringsCache* cache;
+  int index;
+
+  CacheAndIndex(js::SharedImmutableStringsCache* cache, int index)
+      : cache(cache), index(index) {}
+};
+
+static void getString(CacheAndIndex* cacheAndIndex) {
+  for (int i = 0; i < NUM_ITERATIONS; i++) {
+    auto str = STRINGS[cacheAndIndex->index % NUM_STRINGS];
+
+    auto dupe = js::DuplicateString(str);
+    MOZ_RELEASE_ASSERT(dupe);
+
+    auto deduped =
+        cacheAndIndex->cache->getOrCreate(std::move(dupe), js_strlen(str));
+    MOZ_RELEASE_ASSERT(deduped);
+    MOZ_RELEASE_ASSERT(
+        js::EqualChars(str, deduped.chars(), js_strlen(str) + 1));
+
+    {
+      auto cloned = deduped.clone();
+      // We should be de-duplicating and giving back the same string.
+      MOZ_RELEASE_ASSERT(deduped.chars() == cloned.chars());
+    }
+  }
+
+  js_delete(cacheAndIndex);
+}
+
+BEGIN_TEST(testSharedImmutableStringsCache) {
+  auto& cache = js::SharedImmutableStringsCache::getSingleton();
+
+  js::Vector<js::Thread> threads(cx);
+  CHECK(threads.reserve(NUM_THREADS));
+
+  for (auto i : mozilla::IntegerRange(NUM_THREADS)) {
+    auto cacheAndIndex = js_new<CacheAndIndex>(&cache, i);
+    CHECK(cacheAndIndex);
+    threads.infallibleEmplaceBack();
+    CHECK(threads.back().init(getString, cacheAndIndex));
+  }
+
+  for (auto& thread : threads) {
+    thread.join();
+  }
+
+  return true;
+}
+END_TEST(testSharedImmutableStringsCache)