[heap] Simplify mark-compact after double field unboxing deletion

Bug: v8:11422
Change-Id: I106b2226d531d7a868ac9344cce8c965250316e1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2690589Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72692}

src/heap/gc-tracer.cc

@@ -744,7 +744,6 @@ void GCTracer::PrintNVP() const {
           "evacuate.update_pointers=%.1f "
           "evacuate.update_pointers.to_new_roots=%.1f "
           "evacuate.update_pointers.slots.main=%.1f "
-          "evacuate.update_pointers.slots.map_space=%.1f "
           "evacuate.update_pointers.weak=%.1f "
           "finish=%.1f "
           "finish.sweep_array_buffers=%.1f "
@@ -836,7 +835,6 @@ void GCTracer::PrintNVP() const {
           current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS],
           current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS],
           current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_SLOTS_MAIN],
-          current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_SLOTS_MAP_SPACE],
           current_.scopes[Scope::MC_EVACUATE_UPDATE_POINTERS_WEAK],
           current_.scopes[Scope::MC_FINISH],
           current_.scopes[Scope::MC_FINISH_SWEEP_ARRAY_BUFFERS],

src/heap/mark-compact.cc

@@ -3930,6 +3930,8 @@ void MarkCompactCollector::UpdatePointersAfterEvacuation() {
                                       RememberedSetUpdatingMode::ALL);
     CollectRememberedSetUpdatingItems(&updating_items, heap()->code_lo_space(),
                                       RememberedSetUpdatingMode::ALL);
+    CollectRememberedSetUpdatingItems(&updating_items, heap()->map_space(),
+                                      RememberedSetUpdatingMode::ALL);
 
     CollectToSpaceUpdatingItems(&updating_items);
     updating_items.push_back(
@@ -3944,27 +3946,6 @@ void MarkCompactCollector::UpdatePointersAfterEvacuation() {
         ->Join();
   }
 
-  {
-    // - Update array buffer trackers in the second phase to have access to
-    //   byte length which is potentially a HeapNumber.
-    TRACE_GC(heap()->tracer(),
-             GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_SLOTS_MAP_SPACE);
-    std::vector<std::unique_ptr<UpdatingItem>> updating_items;
-
-    CollectRememberedSetUpdatingItems(&updating_items, heap()->map_space(),
-                                      RememberedSetUpdatingMode::ALL);
-    if (!updating_items.empty()) {
-      V8::GetCurrentPlatform()
-          ->PostJob(
-              v8::TaskPriority::kUserBlocking,
-              std::make_unique<PointersUpdatingJob>(
-                  isolate(), std::move(updating_items),
-                  GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_PARALLEL,
-                  GCTracer::Scope::MC_BACKGROUND_EVACUATE_UPDATE_POINTERS))
-          ->Join();
-    }
-  }
-
   {
     TRACE_GC(heap()->tracer(),
              GCTracer::Scope::MC_EVACUATE_UPDATE_POINTERS_WEAK);

src/init/heap-symbols.h

@@ -451,7 +451,6 @@
   F(MC_EVACUATE_UPDATE_POINTERS)                     \
   F(MC_EVACUATE_UPDATE_POINTERS_PARALLEL)            \
   F(MC_EVACUATE_UPDATE_POINTERS_SLOTS_MAIN)          \
-  F(MC_EVACUATE_UPDATE_POINTERS_SLOTS_MAP_SPACE)     \
   F(MC_EVACUATE_UPDATE_POINTERS_TO_NEW_ROOTS)        \
   F(MC_EVACUATE_UPDATE_POINTERS_WEAK)                \
   F(MC_FINISH_SWEEP_ARRAY_BUFFERS)                   \