[handles] Check whether main thread local heap is parked on dereference

When dereferencing handles check whether the main thread is parked
similar to background threads.

Bug: chromium:1152995
Change-Id: Ic79680f1b1c49f5f0ad872d6377ca45920a18b98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2575061Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Georg Neis (ooo until January 5) <neis@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71760}

src/compiler/pipeline.cc

@@ -3295,6 +3295,7 @@ bool PipelineImpl::SelectInstructions(Linkage* linkage) {
   DCHECK_NOT_NULL(data->schedule());
 
   if (FLAG_turbo_profiling) {
+    UnparkedScopeIfNeeded unparked_scope(data->broker());
     data->info()->set_profiler_data(BasicBlockInstrumentor::Instrument(
         info(), data->graph(), data->schedule(), data->isolate()));
   }

src/execution/isolate.cc

@@ -4770,6 +4770,11 @@ LocalHeap* Isolate::main_thread_local_heap() {
   return main_thread_local_isolate()->heap();
 }
 
+LocalHeap* Isolate::CurrentLocalHeap() {
+  LocalHeap* local_heap = LocalHeap::Current();
+  return local_heap ? local_heap : main_thread_local_heap();
+}
+
 // |chunk| is either a Page or an executable LargePage.
 void Isolate::RemoveCodeMemoryChunk(MemoryChunk* chunk) {
   // We only keep track of individual code pages/allocations if we are on arm32,

src/execution/isolate.h

@@ -1638,6 +1638,7 @@ class V8_EXPORT_PRIVATE Isolate final : private HiddenFactory {
   }
 
   LocalHeap* main_thread_local_heap();
+  LocalHeap* CurrentLocalHeap();
 
 #ifdef V8_HEAP_SANDBOX
   ExternalPointerTable& external_pointer_table() {

src/handles/handles.cc

@@ -46,8 +46,9 @@ bool HandleBase::IsDereferenceAllowed() const {
   if (isolate->IsBuiltinsTableHandleLocation(location_)) return true;
   if (!AllowHandleDereference::IsAllowed()) return false;
 
-  LocalHeap* local_heap = LocalHeap::Current();
-  if (FLAG_local_heaps && local_heap) {
+  if (FLAG_local_heaps) {
+    LocalHeap* local_heap = isolate->CurrentLocalHeap();
+
     // Local heap can't access handles when parked
     if (!local_heap->IsHandleDereferenceAllowed()) {
       StdoutStream{} << "Cannot dereference handle owned by "
@@ -55,17 +56,19 @@ bool HandleBase::IsDereferenceAllowed() const {
       return false;
     }
 
+    // We are pretty strict with handle dereferences on background threads: A
+    // background local heap is only allowed to dereference its own local or
+    // persistent handles.
+    if (!local_heap->is_main_thread()) {
       // The current thread owns the handle and thus can dereference it.
       return local_heap->ContainsPersistentHandle(location_) ||
              local_heap->ContainsLocalHandle(location_);
     }
-  // If the local_heap is null, we're on the main thread -- if we were to check
-  // main thread HandleScopes here, we should additionally check the main-thread
-  // LocalHeap.
-  DCHECK_EQ(ThreadId::Current(), isolate->thread_id());
-  if (FLAG_local_heaps) {
-    DCHECK_NOT_NULL(isolate->main_thread_local_heap());
   }
+  // If LocalHeap::Current() is null, we're on the main thread -- if we were to
+  // check main thread HandleScopes here, we should additionally check the
+  // main-thread LocalHeap.
+  DCHECK_EQ(ThreadId::Current(), isolate->thread_id());
 
   // TODO(leszeks): Check if the main thread owns this handle.
   return true;