Compact weak fixed arrays before serializing.

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 1761 matching lines @@
 void Serializer::ObjectSerializer::Serialize() {
   if (FLAG_trace_serializer) {
     PrintF(" Encoding heap object: ");
     object_->ShortPrint();
     PrintF("\n");
   }
 
   // We cannot serialize typed array objects correctly.
   DCHECK(!object_->IsJSTypedArray());
 
+  if (object_->IsPrototypeInfo()) {
+    Object* prototype_users = PrototypeInfo::cast(object_)->prototype_users();
+    if (prototype_users->IsWeakFixedArray()) {
+      WeakFixedArray::cast(prototype_users)->Compact();
+    }
+  }
+
   if (object_->IsScript()) {
     // Clear cached line ends.
     Object* undefined = serializer_->isolate()->heap()->undefined_value();
     Script::cast(object_)->set_line_ends(undefined);
   }
 
   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
@@ skipping 799 matching lines @@
   DisallowHeapAllocation no_gc;
   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 v8::internal