Serializer: ensure unique script ids when deserializing.

src/factory.cc

 // Copyright 2014 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/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/conversions.h"
 #include "src/isolate-inl.h"
@@ skipping 807 matching lines @@
 Handle<ExecutableAccessorInfo> Factory::NewExecutableAccessorInfo() {
   Handle<ExecutableAccessorInfo> info =
       Handle<ExecutableAccessorInfo>::cast(
           NewStruct(EXECUTABLE_ACCESSOR_INFO_TYPE));
   info->set_flag(0);  // Must clear the flag, it was initialized as undefined.
   return info;
 }
 
 
 Handle<Script> Factory::NewScript(Handle<String> source) {
-  // Generate id for this script.
+  // Create and initialize script object.
   Heap* heap = isolate()->heap();
-  int id = heap->last_script_id()->value() + 1;
-  if (!Smi::IsValid(id) || id < 0) id = 1;
-  heap->set_last_script_id(Smi::FromInt(id));
-
-  // Create and initialize script object.
   Handle<Script> script = Handle<Script>::cast(NewStruct(SCRIPT_TYPE));
   script->set_source(*source);
   script->set_name(heap->undefined_value());
-  script->set_id(Smi::FromInt(id));
+  script->set_id(isolate()->heap()->NextScriptId());
   script->set_line_offset(Smi::FromInt(0));
   script->set_column_offset(Smi::FromInt(0));
   script->set_context_data(heap->undefined_value());
   script->set_type(Smi::FromInt(Script::TYPE_NORMAL));
   script->set_wrapper(heap->undefined_value());
   script->set_line_ends(heap->undefined_value());
   script->set_eval_from_shared(heap->undefined_value());
   script->set_eval_from_instructions_offset(Smi::FromInt(0));
   script->set_flags(Smi::FromInt(0));
 
@@ skipping 1472 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal