[heap] Don't publish marking barrier in final marking step

The barrier is published in the atomic pause following the final step.

Bug: v8:12775
Change-Id: Ia77e1d213cc02a086d7a557999481b633e6b4df4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3582039Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79928}

src/heap/heap.cc

@@ -3947,7 +3947,6 @@ void Heap::FinalizeIncrementalMarkingIncrementally(
                  ThreadKind::kMain);
 
   IgnoreLocalGCRequests ignore_gc_requests(this);
-  SafepointScope safepoint(this);
   InvokeIncrementalMarkingPrologueCallbacks();
   incremental_marking()->FinalizeIncrementally();
   InvokeIncrementalMarkingEpilogueCallbacks();

src/heap/incremental-marking.cc

@@ -423,8 +423,6 @@ void IncrementalMarking::FinalizeIncrementally() {
   // so we can do it only once at the beginning of the finalization.
   RetainMaps();
 
-  MarkingBarrier::PublishAll(heap());
-
   finalize_marking_completed_ = true;
 
   if (FLAG_trace_incremental_marking) {

src/heap/marking-barrier.h

@@ -30,7 +30,7 @@ class MarkingBarrier {
 
   static void ActivateAll(Heap* heap, bool is_compacting);
   static void DeactivateAll(Heap* heap);
-  static void PublishAll(Heap* heap);
+  V8_EXPORT_PRIVATE static void PublishAll(Heap* heap);
 
   void Write(HeapObject host, HeapObjectSlot, HeapObject value);
   void Write(Code host, RelocInfo*, HeapObject value);

test/cctest/heap/heap-utils.cc

@@ -10,6 +10,7 @@
 #include "src/heap/heap-inl.h"
 #include "src/heap/incremental-marking.h"
 #include "src/heap/mark-compact.h"
+#include "src/heap/marking-barrier.h"
 #include "src/heap/memory-chunk.h"
 #include "src/heap/safepoint.h"
 #include "test/cctest/cctest.h"
@@ -189,6 +190,7 @@ void SimulateIncrementalMarking(i::Heap* heap, bool force_completion) {
                   i::StepOrigin::kV8);
     if (marking->IsReadyToOverApproximateWeakClosure()) {
       SafepointScope scope(heap);
+      MarkingBarrier::PublishAll(heap);
       marking->MarkRootsForTesting();
       marking->FinalizeIncrementally();
     }

test/cctest/heap/test-heap.cc

@@ -48,6 +48,7 @@
 #include "src/heap/incremental-marking.h"
 #include "src/heap/large-spaces.h"
 #include "src/heap/mark-compact.h"
+#include "src/heap/marking-barrier.h"
 #include "src/heap/memory-chunk.h"
 #include "src/heap/memory-reducer.h"
 #include "src/heap/parked-scope.h"
@@ -5654,6 +5655,7 @@ TEST(Regress598319) {
                   StepOrigin::kV8);
     if (marking->IsReadyToOverApproximateWeakClosure()) {
       SafepointScope safepoint_scope(heap);
+      MarkingBarrier::PublishAll(heap);
       marking->FinalizeIncrementally();
     }
   }