Clone both descriptor and data array when compiling in background

runtime/vm/object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 1923 matching lines @@
   bool HasOneTarget() const;
   bool HasReceiverClassId(intptr_t class_id) const;
 
   static RawICData* New(const Function& owner,
                         const String& target_name,
                         const Array& arguments_descriptor,
                         intptr_t deopt_id,
                         intptr_t num_args_tested);
   static RawICData* NewFrom(const ICData& from, intptr_t num_args_tested);
 
-  // Generates a new ICData with descriptor data copied (shallow clone).
-  // Entry array of the result is the same as in 'from'. Once entry array is
-  // created, it can only change the 'count', all other properties are invariant
-  // (target, cids, number of checks).
-  static RawICData* CloneDescriptor(const ICData& from);
+  // Generates a new ICData with descriptor and data array copied (deep clone).
+  static RawICData* Clone(const ICData& from);
 
   static intptr_t TestEntryLengthFor(intptr_t num_args);
 
   static intptr_t TargetIndexFor(intptr_t num_args) {
     return num_args;
   }
 
   static intptr_t CountIndexFor(intptr_t num_args) {
     return (num_args + 1);
   }
@@ skipping 715 matching lines @@
   int32_t SourceFingerprint() const;
 
   // Return false and report an error if the fingerprint does not match.
   bool CheckSourceFingerprint(const char* prefix, int32_t fp) const;
 
   // Works with map [deopt-id] -> ICData.
   void SaveICDataMap(
       const ZoneGrowableArray<const ICData*>& deopt_id_to_ic_data,
       const Array& edge_counters_array) const;
   // Uses 'ic_data_array' to populate the table 'deopt_id_to_ic_data'. Clone
-  // descriptors if 'clone_descriptors' true.
+  // ic_data (array and descriptor) if 'clone_ic_data' is true.
   void RestoreICDataMap(ZoneGrowableArray<const ICData*>* deopt_id_to_ic_data,
-                        bool clone_descriptors) const;
+                        bool clone_ic_data) const;
 
   RawArray* ic_data_array() const;
   void ClearICDataArray() const;
 
   // Sets deopt reason in all ICData-s with given deopt_id.
   void SetDeoptReasonForAll(intptr_t deopt_id, ICData::DeoptReasonId reason);
 
   void set_modifier(RawFunction::AsyncModifier value) const;
 
   // static: Considered during class-side or top-level resolution rather than
@@ skipping 5733 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_