Revert "Use WeakCells in the optimized code map rather than traversing in pause."

src/heap/objects-visiting-inl.h

Index: src/heap/objects-visiting-inl.h
diff --git a/src/heap/objects-visiting-inl.h b/src/heap/objects-visiting-inl.h
index 80f3a37f921f77523d1558e8a045b07b284a63b6..0e025b22f2af61dabef81bca9136b518c162fc2d 100644
--- a/src/heap/objects-visiting-inl.h
+++ b/src/heap/objects-visiting-inl.h
@@ -442,6 +442,14 @@ void StaticMarkingVisitor<StaticVisitor>::VisitSharedFunctionInfo(
       // Always flush the optimized code map if requested by flag.
       shared->ClearOptimizedCodeMap();
     }
+  } else {
+    if (!shared->OptimizedCodeMapIsCleared()) {
+      // Treat some references within the code map weakly by marking the
+      // code map itself but not pushing it onto the marking deque. The
+      // map will be processed after marking.
+      FixedArray* code_map = shared->optimized_code_map();
+      MarkOptimizedCodeMap(heap, code_map);
+    }
   }
   MarkCompactCollector* collector = heap->mark_compact_collector();
   if (collector->is_code_flushing_enabled()) {
@@ -581,6 +589,23 @@ void StaticMarkingVisitor<StaticVisitor>::MarkTransitionArray(
 
 
 template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::MarkOptimizedCodeMap(
+    Heap* heap, FixedArray* code_map) {
+  if (!StaticVisitor::MarkObjectWithoutPush(heap, code_map)) return;
+
+  // Mark the context-independent entry in the optimized code map. Depending on
+  // the age of the code object, we treat it as a strong or a weak reference.
+  Object* shared_object = code_map->get(SharedFunctionInfo::kSharedCodeIndex);
+  if (FLAG_turbo_preserve_shared_code && shared_object->IsCode() &&
+      FLAG_age_code && !Code::cast(shared_object)->IsOld()) {
+    StaticVisitor::VisitPointer(
+        heap, code_map,
+        code_map->RawFieldOfElementAt(SharedFunctionInfo::kSharedCodeIndex));
+  }
+}
+
+
+template <typename StaticVisitor>
 void StaticMarkingVisitor<StaticVisitor>::MarkInlinedFunctionsCode(Heap* heap,
                                                                    Code* code) {
   // For optimized functions we should retain both non-optimized version