[heap] Added NewToOld page promotion test using JSArrayBuffers.

Bug: chromium:845409
Change-Id: I7a4e19529193f7e8369b7db02c7bcf01ae302ee3
Reviewed-on: https://chromium-review.googlesource.com/1113439
Commit-Queue: Rodrigo Bruno <rfbpb@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54002}

test/cctest/heap/test-page-promotion.cc

@@ -160,6 +160,49 @@ UNINITIALIZED_TEST(PagePromotion_NewToNewJSArrayBuffer) {
   isolate->Dispose();
 }
 
+UNINITIALIZED_TEST(PagePromotion_NewToOldJSArrayBuffer) {
+  if (!i::FLAG_page_promotion) return;
+
+  // Test makes sure JSArrayBuffer backing stores are still tracked after
+  // new-to-old promotion.
+  v8::Isolate* isolate = NewIsolateForPagePromotion();
+  Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
+  {
+    v8::Isolate::Scope isolate_scope(isolate);
+    v8::HandleScope handle_scope(isolate);
+    v8::Context::New(isolate)->Enter();
+    Heap* heap = i_isolate->heap();
+
+    // Fill the current page which potentially contains the age mark.
+    heap::FillCurrentPage(heap->new_space());
+    // Allocate a buffer we would like to check against.
+    Handle<JSArrayBuffer> buffer =
+        i_isolate->factory()->NewJSArrayBuffer(SharedFlag::kNotShared);
+    CHECK(JSArrayBuffer::SetupAllocatingData(buffer, i_isolate, 100));
+    std::vector<Handle<FixedArray>> handles;
+    // Simulate a full space, filling the interesting page with live objects.
+    heap::SimulateFullSpace(heap->new_space(), &handles);
+    CHECK_GT(handles.size(), 0u);
+    // First object in handles should be on the same page as the allocated
+    // JSArrayBuffer.
+    Handle<FixedArray> first_object = handles.front();
+    Page* to_be_promoted_page = Page::FromAddress(first_object->address());
+    CHECK(!to_be_promoted_page->Contains(heap->new_space()->age_mark()));
+    CHECK(to_be_promoted_page->Contains(first_object->address()));
+    CHECK(to_be_promoted_page->Contains(buffer->address()));
+    CHECK(heap->new_space()->ToSpaceContainsSlow(first_object->address()));
+    CHECK(heap->new_space()->ToSpaceContainsSlow(buffer->address()));
+    heap::GcAndSweep(heap, OLD_SPACE);
+    heap::GcAndSweep(heap, OLD_SPACE);
+    CHECK(heap->old_space()->ContainsSlow(first_object->address()));
+    CHECK(heap->old_space()->ContainsSlow(buffer->address()));
+    CHECK(to_be_promoted_page->Contains(first_object->address()));
+    CHECK(to_be_promoted_page->Contains(buffer->address()));
+    CHECK(ArrayBufferTracker::IsTracked(*buffer));
+  }
+  isolate->Dispose();
+}
+
 UNINITIALIZED_HEAP_TEST(Regress658718) {
   if (!i::FLAG_page_promotion) return;