[serializer] Move WeakFixedArray compaction to separate heap walk phase

src/snapshot/serialize.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 1905 matching lines @@
     object_->ShortPrint();
     PrintF("\n");
   }
 
   // We cannot serialize typed array objects correctly.
   DCHECK(!object_->IsJSTypedArray());
 
   // We don't expect fillers.
   DCHECK(!object_->IsFiller());
 
-  if (object_->IsPrototypeInfo()) {
-    Object* prototype_users = PrototypeInfo::cast(object_)->prototype_users();
-    if (prototype_users->IsWeakFixedArray()) {
-      WeakFixedArray* array = WeakFixedArray::cast(prototype_users);
-      array->Compact<JSObject::PrototypeRegistryCompactionCallback>();
-    }
-  }
-  // Compaction of a prototype users list can require the registered users
-  // to update their remembered slots. That doesn't work if those users
-  // have already been serialized themselves. So if this object is a
-  // registered user, compact its prototype's user list now.
-  if (object_->IsMap()) {
-    Map* map = Map::cast(object_);
-    if (map->is_prototype_map() && map->prototype_info()->IsPrototypeInfo() &&
-        PrototypeInfo::cast(map->prototype_info())->registry_slot() !=
-            PrototypeInfo::UNREGISTERED) {
-      JSObject* proto = JSObject::cast(map->prototype());
-      PrototypeInfo* info = PrototypeInfo::cast(proto->map()->prototype_info());
-      WeakFixedArray* array = WeakFixedArray::cast(info->prototype_users());
-      array->Compact<JSObject::PrototypeRegistryCompactionCallback>();
-    }
-  }
-
   if (object_->IsScript()) {
     // Clear cached line ends.
     Object* undefined = serializer_->isolate()->heap()->undefined_value();
     Script::cast(object_)->set_line_ends(undefined);
-    Object* shared_list = Script::cast(object_)->shared_function_infos();
-    if (shared_list->IsWeakFixedArray()) {
-      WeakFixedArray::cast(shared_list)
-          ->Compact<WeakFixedArray::NullCallback>();
-    }
   }
 
   if (object_->IsExternalString()) {
     Heap* heap = serializer_->isolate()->heap();
     if (object_->map() != heap->native_source_string_map()) {
       // Usually we cannot recreate resources for external strings. To work
       // around this, external strings are serialized to look like ordinary
       // sequential strings.
       // The exception are native source code strings, since we can recreate
       // their resources. In that case we fall through and leave it to
@@ skipping 832 matching lines @@
   SerializedCodeData* scd = new SerializedCodeData(cached_data);
   SanityCheckResult r = scd->SanityCheck(isolate, source);
   if (r == CHECK_SUCCESS) return scd;
   cached_data->Reject();
   source->GetIsolate()->counters()->code_cache_reject_reason()->AddSample(r);
   delete scd;
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8