Clone both descriptor and data array when compiling in background

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 6766 matching lines @@
       array.SetAt(count++, *deopt_id_to_ic_data[i]);
     }
   }
   array.SetAt(0, edge_counters_array);
   set_ic_data_array(array);
 }
 
 
 void Function::RestoreICDataMap(
     ZoneGrowableArray<const ICData*>* deopt_id_to_ic_data,
-    bool clone_descriptors) const {
+    bool clone_ic_data) const {
   ASSERT(deopt_id_to_ic_data->is_empty());
   Zone* zone = Thread::Current()->zone();
   const Array& saved_ic_data = Array::Handle(zone, ic_data_array());
   if (saved_ic_data.IsNull()) {
     // Could happen with deferred loading.
     return;
   }
   const intptr_t saved_length = saved_ic_data.Length();
   ASSERT(saved_length > 0);
   if (saved_length > 1) {
     const intptr_t restored_length = ICData::Cast(Object::Handle(
         zone, saved_ic_data.At(saved_length - 1))).deopt_id() + 1;
     deopt_id_to_ic_data->SetLength(restored_length);
     for (intptr_t i = 0; i < restored_length; i++) {
       (*deopt_id_to_ic_data)[i] = NULL;
     }
     for (intptr_t i = 1; i < saved_length; i++) {
       ICData& ic_data = ICData::ZoneHandle(zone);
       ic_data ^= saved_ic_data.At(i);
-      if (clone_descriptors) {
-        ICData& original_ic_data = ICData::Handle(zone, ic_data.raw());
-        ic_data = ICData::CloneDescriptor(ic_data);
+      if (clone_ic_data) {
+        const ICData& original_ic_data = ICData::Handle(zone, ic_data.raw());
+        ic_data = ICData::CloneDescriptorAndData(ic_data);
         ic_data.SetOriginal(original_ic_data);
       }
       (*deopt_id_to_ic_data)[ic_data.deopt_id()] = &ic_data;
     }
   }
 }
 
 
 void Function::set_ic_data_array(const Array& value) const {
   StorePointer(&raw_ptr()->ic_data_array_, value.raw());
@@ skipping 5479 matching lines @@
       String::Handle(from.target_name()),
       Array::Handle(from.arguments_descriptor()),
       from.deopt_id(),
       num_args_tested));
   // Copy deoptimization reasons.
   result.SetDeoptReasons(from.DeoptReasons());
   return result.raw();
 }
 
 
-RawICData* ICData::CloneDescriptor(const ICData& from) {
+RawICData* ICData::CloneDescriptorAndData(const ICData& from) {
   Zone* zone = Thread::Current()->zone();
   const ICData& result = ICData::Handle(ICData::NewDescriptor(
       zone,
       Function::Handle(zone, from.Owner()),
       String::Handle(zone, from.target_name()),
       Array::Handle(zone, from.arguments_descriptor()),
       from.deopt_id(),
       from.NumArgsTested()));
-  // Preserve entry array.
-  result.set_ic_data_array(Array::Handle(zone, from.ic_data()));
+  // Clone entry array.
+  const Array& from_array = Array::Handle(zone, from.ic_data());
+  const intptr_t len = from_array.Length();
+  const Array& cloned_array =
+      Array::Handle(zone, Array::New(len, Heap::kOld));
+  Object& obj = Object::Handle(zone);
+  for (intptr_t i = 0; i < len; i++) {
+    obj = from_array.At(i);
+    cloned_array.SetAt(i, obj);
+  }

[siva, 2016/02/12 22:10:24]

I think there are many places where we do this array copy, maybe we should have
a makeCopy method in array that can be used in all these places. I will do that
in a different cl.

[srdjan, 2016/02/12 22:20:38]

Sounds good.

+  result.set_ic_data_array(cloned_array);
   // Copy deoptimization reasons.
   result.SetDeoptReasons(from.DeoptReasons());
   return result.raw();
 }
 
 
 static Token::Kind RecognizeArithmeticOp(const String& name) {
   ASSERT(name.IsSymbol());
   if (name.raw() == Symbols::Plus().raw()) {
     return Token::kADD;
@@ skipping 9087 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart