cppgc: Extract NotifySweepingCompleted from Sweeper::Finish

This is required for enabling scopes such that NotifySweepingCompleted
is not called from within a scope.

Bug: chromium:1056170
Change-Id: Ia66aa4de8c22bfa7dfe1e02ee1e0d3ad088f7bf6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2549761Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71282}

src/heap/cppgc-js/cpp-heap.cc

@@ -243,6 +243,7 @@ void CppHeap::TraceEpilogue(TraceSummary* trace_summary) {
         compactable_space_handling};
     sweeper().Start(sweeping_config);
   }
+  sweeper().NotifyDoneIfNeeded();
 }
 
 }  // namespace internal

src/heap/cppgc-js/cpp-heap.h

@@ -54,6 +54,8 @@ class V8_EXPORT_PRIVATE CppHeap final : public cppgc::internal::HeapBase,
     // finalization is not needed) thus this method is left empty.
   }
 
+  void PostGarbageCollection() final {}
+
   Isolate& isolate_;
   bool marking_done_ = false;
 };

src/heap/cppgc/heap-base.h

@@ -139,6 +139,9 @@ class V8_EXPORT_PRIVATE HeapBase {
 
   void AdvanceIncrementalGarbageCollectionOnAllocationIfNeeded();
 
+  // Notifies the heap that a GC is done.
+  virtual void PostGarbageCollection() = 0;
+
  protected:
   virtual void FinalizeIncrementalGarbageCollectionIfNeeded(
       cppgc::Heap::StackState) = 0;

src/heap/cppgc/heap.cc

@@ -173,9 +173,11 @@ void Heap::FinalizeGarbageCollection(Config::StackState stack_state) {
         Sweeper::SweepingConfig::CompactableSpaceHandling::kSweep};
     sweeper_.Start(sweeping_config);
   }
-  gc_in_progress_ = false;
+  sweeper_.NotifyDoneIfNeeded();
 }
 
+void Heap::PostGarbageCollection() { gc_in_progress_ = false; }
+
 void Heap::DisableHeapGrowingForTesting() { growing_.DisableForTesting(); }
 
 }  // namespace internal

src/heap/cppgc/heap.h

@@ -49,6 +49,8 @@ class V8_EXPORT_PRIVATE Heap final : public HeapBase,
     FinalizeGarbageCollection(stack_state);
   }
 
+  void PostGarbageCollection() final;
+
   Config config_;
   GCInvoker gc_invoker_;
   HeapGrowing growing_;

src/heap/cppgc/sweeper.cc

@@ -13,6 +13,7 @@
 #include "src/base/platform/mutex.h"
 #include "src/heap/cppgc/free-list.h"
 #include "src/heap/cppgc/globals.h"
+#include "src/heap/cppgc/heap-base.h"
 #include "src/heap/cppgc/heap-object-header.h"
 #include "src/heap/cppgc/heap-page.h"
 #include "src/heap/cppgc/heap-space.h"
@@ -523,6 +524,7 @@ class Sweeper::SweeperImpl final {
           cppgc::TaskPriority::kUserBlocking);
     }
     Finish();
+    NotifyDone();
   }
 
   void Finish() {
@@ -536,12 +538,28 @@ class Sweeper::SweeperImpl final {
     MutatorThreadSweeper sweeper(&space_states_, platform_);
     sweeper.Sweep();
 
+    FinalizeSweep();
+  }
+
+  void FinalizeSweep() {
     // Synchronize with the concurrent sweeper and call remaining finalizers.
     SynchronizeAndFinalizeConcurrentSweeping();
-
     is_in_progress_ = false;
+    notify_done_pending_ = true;
+  }
 
+  void NotifyDone() {
+    DCHECK(!is_in_progress_);
+    DCHECK(notify_done_pending_);
+    notify_done_pending_ = false;
     stats_collector_->NotifySweepingCompleted();
+    // Notify the heap that GC is finished.
+    heap_->heap()->PostGarbageCollection();
+  }
+
+  void NotifyDoneIfNeeded() {
+    if (!notify_done_pending_) return;
+    NotifyDone();
   }
 
   void WaitForConcurrentSweepingForTesting() {
@@ -573,7 +591,8 @@ class Sweeper::SweeperImpl final {
           sweeper.SweepWithDeadline(deadline_in_seconds);
 
       if (sweep_complete) {
-        sweeper_->SynchronizeAndFinalizeConcurrentSweeping();
+        sweeper_->FinalizeSweep();
+        sweeper_->NotifyDone();
       } else {
         sweeper_->ScheduleIncrementalSweeping();
       }
@@ -625,6 +644,7 @@ class Sweeper::SweeperImpl final {
   IncrementalSweepTask::Handle incremental_sweeper_handle_;
   std::unique_ptr<cppgc::JobHandle> concurrent_sweeper_handle_;
   bool is_in_progress_ = false;
+  bool notify_done_pending_ = false;
 };
 
 Sweeper::Sweeper(RawHeap* heap, cppgc::Platform* platform,
@@ -638,6 +658,7 @@ void Sweeper::FinishIfRunning() { impl_->FinishIfRunning(); }
 void Sweeper::WaitForConcurrentSweepingForTesting() {
   impl_->WaitForConcurrentSweepingForTesting();
 }
+void Sweeper::NotifyDoneIfNeeded() { impl_->NotifyDoneIfNeeded(); }
 
 }  // namespace internal
 }  // namespace cppgc

src/heap/cppgc/sweeper.h

@@ -39,6 +39,7 @@ class V8_EXPORT_PRIVATE Sweeper final {
   // Sweeper::Start assumes the heap holds no linear allocation buffers.
   void Start(SweepingConfig);
   void FinishIfRunning();
+  void NotifyDoneIfNeeded();
 
  private:
   void WaitForConcurrentSweepingForTesting();