[heap] Register end of black areas to support faster filtering of invalid slots.

test/cctest/heap/test-heap.cc

Index: test/cctest/heap/test-heap.cc
diff --git a/test/cctest/heap/test-heap.cc b/test/cctest/heap/test-heap.cc
index d4ebd04898bea1c8e024c534115c3ab52faa6240..c53c77ebfa81ce80847e125e49af4f051e5198dd 100644
--- a/test/cctest/heap/test-heap.cc
+++ b/test/cctest/heap/test-heap.cc
@@ -6986,6 +6986,48 @@ TEST(ContinuousRightTrimFixedArrayInBlackArea) {
   heap::GcAndSweep(heap, OLD_SPACE);
 }
 
+TEST(SlotFilteringAfterBlackAreas) {
+  FLAG_black_allocation = true;
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Heap* heap = CcTest::heap();
+  Isolate* isolate = heap->isolate();
+  MarkCompactCollector* mark_compact_collector = heap->mark_compact_collector();
+  heap->CollectAllGarbage();
+
+  i::MarkCompactCollector* collector = heap->mark_compact_collector();
+  i::IncrementalMarking* marking = heap->incremental_marking();
+  if (collector->sweeping_in_progress()) {
+    collector->EnsureSweepingCompleted();
+  }
+  CHECK(marking->IsMarking() || marking->IsStopped());
+  if (marking->IsStopped()) {
+    heap->StartIncrementalMarking();
+  }
+  CHECK(marking->IsMarking());
+  marking->StartBlackAllocationForTesting();
+
+  // Ensure that we allocate a new page, set up a bump pointer area, and
+  // perform the allocation in a black area.
+  heap::SimulateFullSpace(heap->old_space());
+  Handle<FixedArray> array = isolate->factory()->NewFixedArray(10, TENURED);
+  Page* page = Page::FromAddress(array->address());
+
+  // After allocation we empty the allocation info to limit the black area
+  // only on the allocated array.
+  heap->old_space()->EmptyAllocationInfo();
+
+  // Slots in the black area are part of the black object.
+  CHECK(mark_compact_collector->IsSlotInBlackObject(page, array->address()));
+  CHECK(mark_compact_collector->IsSlotInBlackObject(
+      page, array->address() + array->Size() - kPointerSize));
+
+  // Slots after the black area are not part of the black object and have to
+  // be filtered out.
+  CHECK(!mark_compact_collector->IsSlotInBlackObject(
+      page, array->address() + array->Size()));
+}
+
 TEST(Regress618958) {
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());