1 files changed, 123 insertions, 0 deletions
diff --git a/js/src/jsapi-tests/testGCUniqueId.cpp b/js/src/jsapi-tests/testGCUniqueId.cpp
new file mode 100644
index 000000000..71d66b722
--- /dev/null
+++ b/js/src/jsapi-tests/testGCUniqueId.cpp
@@ -0,0 +1,123 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+* vim: set ts=8 sts=4 et sw=4 tw=99:
+*/
+/* 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 "gc/GCInternals.h"
+#include "gc/Zone.h"
+#include "js/GCVector.h"
+
+#include "jsapi-tests/tests.h"
+
+static void
+MinimizeHeap(JSContext* cx)
+{
+    // The second collection is to force us to wait for the background
+    // sweeping that the first GC started to finish.
+    JS_GC(cx);
+    JS_GC(cx);
+    js::gc::FinishGC(cx);
+}
+
+BEGIN_TEST(testGCUID)
+{
+#ifdef JS_GC_ZEAL
+    AutoLeaveZeal nozeal(cx);
+#endif /* JS_GC_ZEAL */
+
+    uint64_t uid = 0;
+    uint64_t tmp = 0;
+
+    // Ensure the heap is as minimal as it can get.
+    MinimizeHeap(cx);
+
+    JS::RootedObject obj(cx, JS_NewPlainObject(cx));
+    uintptr_t nurseryAddr = uintptr_t(obj.get());
+    CHECK(obj);
+    CHECK(js::gc::IsInsideNursery(obj));
+
+    // Do not start with an ID.
+    CHECK(!obj->zone()->hasUniqueId(obj));
+
+    // Ensure we can get a new UID.
+    CHECK(obj->zone()->getUniqueId(obj, &uid));
+    CHECK(uid > js::gc::LargestTaggedNullCellPointer);
+
+    // We should now have an id.
+    CHECK(obj->zone()->hasUniqueId(obj));
+
+    // Calling again should get us the same thing.
+    CHECK(obj->zone()->getUniqueId(obj, &tmp));
+    CHECK(uid == tmp);
+
+    // Tenure the thing and check that the UID moved with it.
+    MinimizeHeap(cx);
+    uintptr_t tenuredAddr = uintptr_t(obj.get());
+    CHECK(tenuredAddr != nurseryAddr);
+    CHECK(!js::gc::IsInsideNursery(obj));
+    CHECK(obj->zone()->hasUniqueId(obj));
+    CHECK(obj->zone()->getUniqueId(obj, &tmp));
+    CHECK(uid == tmp);
+
+    // Allocate a new nursery thing in the same location and check that we
+    // removed the prior uid that was attached to the location.
+    obj = JS_NewPlainObject(cx);
+    CHECK(obj);
+    CHECK(uintptr_t(obj.get()) == nurseryAddr);
+    CHECK(!obj->zone()->hasUniqueId(obj));
+
+    // Try to get another tenured object in the same location and check that
+    // the uid was removed correctly.
+    obj = nullptr;
+    MinimizeHeap(cx);
+    obj = JS_NewPlainObject(cx);
+    MinimizeHeap(cx);
+    CHECK(uintptr_t(obj.get()) == tenuredAddr);
+    CHECK(!obj->zone()->hasUniqueId(obj));
+    CHECK(obj->zone()->getUniqueId(obj, &tmp));
+    CHECK(uid != tmp);
+    uid = tmp;
+
+    // Allocate a few arenas worth of objects to ensure we get some compaction.
+    const static size_t N = 2049;
+    using ObjectVector = JS::GCVector<JSObject*>;
+    JS::Rooted<ObjectVector> vec(cx, ObjectVector(cx));
+    for (size_t i = 0; i < N; ++i) {
+        obj = JS_NewPlainObject(cx);
+        CHECK(obj);
+        CHECK(vec.append(obj));
+    }
+
+    // Transfer our vector to tenured if it isn't there already.
+    MinimizeHeap(cx);
+
+    // Tear holes in the heap by unrooting the even objects and collecting.
+    JS::Rooted<ObjectVector> vec2(cx, ObjectVector(cx));
+    for (size_t i = 0; i < N; ++i) {
+        if (i % 2 == 1)
+            vec2.append(vec[i]);
+    }
+    vec.clear();
+    MinimizeHeap(cx);
+
+    // Grab the last object in the vector as our object of interest.
+    obj = vec2.back();
+    CHECK(obj);
+    tenuredAddr = uintptr_t(obj.get());
+    CHECK(obj->zone()->getUniqueId(obj, &uid));
+
+    // Force a compaction to move the object and check that the uid moved to
+    // the new tenured heap location.
+    JS::PrepareForFullGC(cx);
+    JS::GCForReason(cx, GC_SHRINK, JS::gcreason::API);
+    MinimizeHeap(cx);
+    CHECK(uintptr_t(obj.get()) != tenuredAddr);
+    CHECK(obj->zone()->hasUniqueId(obj));
+    CHECK(obj->zone()->getUniqueId(obj, &tmp));
+    CHECK(uid == tmp);
+
+    return true;
+}
+END_TEST(testGCUID)