[handles] Do not allow handle deref when local heap is parked

When local heap is parked it is not allowed to dereference any handles.
A GC might be relocating objects at that point.

Change-Id: I557682d47f8f0acfe041506833f6b397feb4438b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2289981Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68768}

src/handles/handles.cc

@@ -35,20 +35,24 @@ bool HandleBase::IsDereferenceAllowed() const {
   HeapObject heap_object = HeapObject::cast(object);
   if (IsReadOnlyHeapObject(heap_object)) return true;
   if (Heap::InOffThreadSpace(heap_object)) return true;
+  Isolate* isolate = GetIsolateFromWritableObject(heap_object);
+  RootIndex root_index;
+  if (isolate->roots_table().IsRootHandleLocation(location_, &root_index) &&
+      RootsTable::IsImmortalImmovable(root_index)) {
+    return true;
+  }
+
   LocalHeap* local_heap = LocalHeap::Current();
   if (V8_UNLIKELY(local_heap)) {
+    // Local heap can't access handles when parked
+    if (!local_heap->IsHandleDereferenceAllowed()) return false;
+
     if (local_heap->ContainsPersistentHandle(location_)) {
       // The current thread owns the handle and thus can dereference it.
       return true;
     }
   }
 
-  Isolate* isolate = GetIsolateFromWritableObject(heap_object);
-  RootIndex root_index;
-  if (isolate->roots_table().IsRootHandleLocation(location_, &root_index) &&
-      RootsTable::IsImmortalImmovable(root_index)) {
-    return true;
-  }
   return AllowHandleDereference::IsAllowed();
 }
 #endif

src/heap/local-heap.cc

@@ -69,6 +69,11 @@ std::unique_ptr<PersistentHandles> LocalHeap::DetachPersistentHandles() {
 bool LocalHeap::ContainsPersistentHandle(Address* location) {
   return persistent_handles_ ? persistent_handles_->Contains(location) : false;
 }
+
+bool LocalHeap::IsHandleDereferenceAllowed() {
+  DCHECK_EQ(LocalHeap::Current(), this);
+  return state_ == ThreadState::Running;
+}
 #endif
 
 bool LocalHeap::IsParked() {

src/heap/local-heap.h

@@ -41,6 +41,7 @@ class V8_EXPORT_PRIVATE LocalHeap {
   std::unique_ptr<PersistentHandles> DetachPersistentHandles();
 #ifdef DEBUG
   bool ContainsPersistentHandle(Address* location);
+  bool IsHandleDereferenceAllowed();
 #endif
 
   bool IsParked();