Make tests pass with weak closure overapproximation enabled

BUG=v8:3862
R=hpayer@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1014873002

Cr-Commit-Position: refs/heads/master@{#27261}

src/heap/heap.cc

@@ -4543,11 +4543,12 @@ void Heap::IdleMarkCompact(const char* message) {
 bool Heap::TryFinalizeIdleIncrementalMarking(
     double idle_time_in_ms, size_t size_of_objects,
     size_t final_incremental_mark_compact_speed_in_bytes_per_ms) {
-  if (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
-      (FLAG_overapproximate_weak_closure &&
-       mark_compact_collector_.marking_deque()->IsEmpty() &&
-       gc_idle_time_handler_.ShouldDoOverApproximateWeakClosure(
-           static_cast<size_t>(idle_time_in_ms)))) {
+  if (FLAG_overapproximate_weak_closure &&
+      (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
+       (!incremental_marking()->weak_closure_was_overapproximated() &&
+        mark_compact_collector_.marking_deque()->IsEmpty() &&
+        gc_idle_time_handler_.ShouldDoOverApproximateWeakClosure(
+            static_cast<size_t>(idle_time_in_ms))))) {
     OverApproximateWeakClosure(
         "Idle notification: overapproximate weak closure");
     return true;

src/heap/incremental-marking.h

@@ -42,6 +42,10 @@ class IncrementalMarking {
     return weak_closure_was_overapproximated_;
   }
 
+  void SetWeakClosureWasOverApproximatedForTesting(bool val) {
+    weak_closure_was_overapproximated_ = val;
+  }
+
   inline bool IsStopped() { return state() == STOPPED; }
 
   INLINE(bool IsMarking()) { return state() >= MARKING; }
@@ -51,7 +55,8 @@ class IncrementalMarking {
   inline bool IsComplete() { return state() == COMPLETE; }
 
   inline bool IsReadyToOverApproximateWeakClosure() const {
-    return request_type_ == OVERAPPROXIMATION;
+    return request_type_ == OVERAPPROXIMATION &&
+           !weak_closure_was_overapproximated_;
   }
 
   GCRequestType request_type() const { return request_type_; }

test/cctest/cctest.h

@@ -558,6 +558,9 @@ static inline void SimulateIncrementalMarking(i::Heap* heap) {
   CHECK(marking->IsMarking());
   while (!marking->IsComplete()) {
     marking->Step(i::MB, i::IncrementalMarking::NO_GC_VIA_STACK_GUARD);
+    if (marking->IsReadyToOverApproximateWeakClosure()) {
+      marking->MarkObjectGroups();
+    }
   }
   CHECK(marking->IsComplete());
 }

test/cctest/test-heap.cc

@@ -2341,6 +2341,8 @@ TEST(IdleNotificationFinishMarking) {
     CHECK(!marking->IsIdleMarkingDelayCounterLimitReached());
   }
 
+  marking->SetWeakClosureWasOverApproximatedForTesting(true);
+
   // The next idle notification has to finish incremental marking.
   const int kLongIdleTime = 1000000;
   CcTest::isolate()->IdleNotification(kLongIdleTime);
@@ -4063,7 +4065,8 @@ TEST(IncrementalMarkingStepMakesBigProgressWithLargeObjects) {
   if (marking->IsStopped()) marking->Start();
   // This big step should be sufficient to mark the whole array.
   marking->Step(100 * MB, IncrementalMarking::NO_GC_VIA_STACK_GUARD);
-  DCHECK(marking->IsComplete());
+  DCHECK(marking->IsComplete() ||
+         marking->IsReadyToOverApproximateWeakClosure());
 }