VM: Allow configuring use_field_guards on the per-isolate basis and include it into snapshot featur…

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/compiler.h"
@@ skipping 3417 matching lines @@
 void EffectGraphVisitor::VisitStoreInstanceFieldNode(
     StoreInstanceFieldNode* node) {
   const TokenPosition token_pos = node->token_pos();
   ValueGraphVisitor for_instance(owner());
   node->instance()->Visit(&for_instance);
   Append(for_instance);
   ValueGraphVisitor for_value(owner());
   node->value()->Visit(&for_value);
   Append(for_value);
   Value* store_value = for_value.value();
-  if (Isolate::Current()->type_checks()) {
+  if (isolate()->type_checks()) {
     const AbstractType& type =
         AbstractType::ZoneHandle(Z, node->field().type());
     const String& dst_name = String::ZoneHandle(Z, node->field().name());
     store_value = BuildAssignableValue(node->value()->token_pos(), store_value,
                                        type, dst_name);
   }
 
-  if (FLAG_use_field_guards) {
+  if (isolate()->use_field_guards()) {
     store_value = Bind(BuildStoreExprTemp(store_value, token_pos));
     GuardFieldClassInstr* guard_field_class = new (Z) GuardFieldClassInstr(
         store_value, node->field(), thread()->GetNextDeoptId());
     AddInstruction(guard_field_class);
     store_value = Bind(BuildLoadExprTemp(token_pos));
     GuardFieldLengthInstr* guard_field_length = new (Z) GuardFieldLengthInstr(
         store_value, node->field(), thread()->GetNextDeoptId());
     AddInstruction(guard_field_length);
     store_value = Bind(BuildLoadExprTemp(token_pos));
   }
@@ skipping 933 matching lines @@
       graph_entry_->PruneUnreachable(graph_entry_, NULL, osr_id_, block_marks);
   ASSERT(found);
 }
 
 
 void FlowGraphBuilder::Bailout(const char* reason) const {
   parsed_function_.Bailout("FlowGraphBuilder", reason);
 }
 
 }  // namespace dart