1 files changed, 140 insertions, 0 deletions
diff --git a/xpcom/glue/tests/gtest/TestGCPostBarriers.cpp b/xpcom/glue/tests/gtest/TestGCPostBarriers.cpp
new file mode 100644
index 000000000..5bf10ab05
--- /dev/null
+++ b/xpcom/glue/tests/gtest/TestGCPostBarriers.cpp
@@ -0,0 +1,140 @@
+/* -*- 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/. */
+
+/*
+ * Tests that generational garbage collection post-barriers are correctly
+ * implemented for nsTArrays that contain JavaScript Values.
+ */
+
+#include "jsapi.h"
+#include "nsTArray.h"
+
+#include "gtest/gtest.h"
+
+#include "js/TracingAPI.h"
+#include "js/HeapAPI.h"
+
+#include "mozilla/CycleCollectedJSContext.h"
+
+using namespace JS;
+using namespace mozilla;
+
+template<class ArrayT>
+static void
+TraceArray(JSTracer* trc, void* data)
+{
+  ArrayT* array = static_cast<ArrayT *>(data);
+  for (unsigned i = 0; i < array->Length(); ++i)
+    JS::TraceEdge(trc, &array->ElementAt(i), "array-element");
+}
+
+/*
+ * Use arrays with initial size much smaller than the final number of elements
+ * to test that moving Heap<T> elements works correctly.
+ */
+const size_t ElementCount = 100;
+const size_t InitialElements = ElementCount / 10;
+
+template<class ArrayT>
+static void
+RunTest(JSContext* cx, ArrayT* array)
+{
+  JS_GC(cx);
+
+  ASSERT_TRUE(array != nullptr);
+  JS_AddExtraGCRootsTracer(cx, TraceArray<ArrayT>, array);
+
+  /*
+   * Create the array and fill it with new JS objects. With GGC these will be
+   * allocated in the nursery.
+   */
+  RootedValue value(cx);
+  const char* property = "foo";
+  for (size_t i = 0; i < ElementCount; ++i) {
+    RootedObject obj(cx, JS_NewPlainObject(cx));
+    ASSERT_FALSE(JS::ObjectIsTenured(obj));
+    value = Int32Value(i);
+    ASSERT_TRUE(JS_SetProperty(cx, obj, property, value));
+    ASSERT_TRUE(array->AppendElement(obj, fallible));
+  }
+
+  /*
+   * If postbarriers are not working, we will crash here when we try to mark
+   * objects that have been moved to the tenured heap.
+   */
+  JS_GC(cx);
+
+  /*
+   * Sanity check that our array contains what we expect.
+   */
+  for (size_t i = 0; i < ElementCount; ++i) {
+    RootedObject obj(cx, array->ElementAt(i));
+    ASSERT_TRUE(JS::ObjectIsTenured(obj));
+    ASSERT_TRUE(JS_GetProperty(cx, obj, property, &value));
+    ASSERT_TRUE(value.isInt32());
+    ASSERT_EQ(static_cast<int32_t>(i), value.toInt32());
+  }
+
+  JS_RemoveExtraGCRootsTracer(cx, TraceArray<ArrayT>, array);
+}
+
+static void
+CreateGlobalAndRunTest(JSContext* cx)
+{
+  static const JSClassOps GlobalClassOps = {
+    nullptr, nullptr, nullptr, nullptr,
+    nullptr, nullptr, nullptr, nullptr,
+    nullptr, nullptr, nullptr,
+    JS_GlobalObjectTraceHook
+  };
+
+  static const JSClass GlobalClass = {
+    "global", JSCLASS_GLOBAL_FLAGS,
+    &GlobalClassOps
+  };
+
+  JS::CompartmentOptions options;
+  options.behaviors().setVersion(JSVERSION_LATEST);
+  JS::PersistentRootedObject global(cx);
+  global = JS_NewGlobalObject(cx, &GlobalClass, nullptr, JS::FireOnNewGlobalHook, options);
+  ASSERT_TRUE(global != nullptr);
+
+  JSCompartment *oldCompartment = JS_EnterCompartment(cx, global);
+
+  typedef Heap<JSObject*> ElementT;
+
+  {
+    nsTArray<ElementT>* array = new nsTArray<ElementT>(InitialElements);
+    RunTest(cx, array);
+    delete array;
+  }
+
+  {
+    FallibleTArray<ElementT>* array = new FallibleTArray<ElementT>(InitialElements);
+    RunTest(cx, array);
+    delete array;
+  }
+
+  {
+    AutoTArray<ElementT, InitialElements> array;
+    RunTest(cx, &array);
+  }
+
+  JS_LeaveCompartment(cx, oldCompartment);
+}
+
+TEST(GCPostBarriers, nsTArray) {
+  CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::Get();
+  ASSERT_TRUE(ccjscx != nullptr);
+  JSContext* cx = ccjscx->Context();
+  ASSERT_TRUE(cx != nullptr);
+
+  JS_BeginRequest(cx);
+
+  CreateGlobalAndRunTest(cx);
+
+  JS_EndRequest(cx);
+}