Deletion barrier: Distinguish+verify field initialization in ia32 generated code.

runtime/vm/flow_graph_builder.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/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 3474 matching lines @@
                                    I->GetNextDeoptId());
   AddInstruction(guard_field_length);
 
   store_value = Bind(BuildLoadExprTemp());
   StoreInstanceFieldInstr* store =
       new(I) StoreInstanceFieldInstr(node->field(),
                                      for_instance.value(),
                                      store_value,
                                      kEmitStoreBarrier,
                                      node->token_pos());
-  store->set_is_initialization(true);  // Maybe initializing store.
+  // Maybe initializing unboxed store.
+  store->set_is_potential_unboxed_initialization(true);
   ReturnDefinition(store);
 }
 
 
 void EffectGraphVisitor::VisitLoadStaticFieldNode(LoadStaticFieldNode* node) {
   if (node->field().is_const()) {
     ASSERT(node->field().value() != Object::sentinel().raw());
     ASSERT(node->field().value() != Object::transition_sentinel().raw());
     Definition* result =
         new(I) ConstantInstr(Instance::ZoneHandle(I, node->field().value()));
@@ skipping 808 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart