Allows turning on checked mode on a per-isolate basis

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2013, 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/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
@@ skipping 886 matching lines @@
   code.set_static_calls_target_table(
       Array::Handle(Array::MakeArray(static_calls_target_table_)));
 }
 
 
 // Returns 'true' if code generation for this function is complete, i.e.,
 // no fall-through to regular code is needed.
 void FlowGraphCompiler::TryIntrinsify() {
   // Intrinsification skips arguments checks, therefore disable if in checked
   // mode.
-  if (FLAG_intrinsify && !FLAG_enable_type_checks) {
+  if (FLAG_intrinsify && !I->TypeChecksEnabled()) {
     if (parsed_function().function().kind() == RawFunction::kImplicitGetter) {
       // An implicit getter must have a specific AST structure.
       const SequenceNode& sequence_node = *parsed_function().node_sequence();
       ASSERT(sequence_node.length() == 1);
       ASSERT(sequence_node.NodeAt(0)->IsReturnNode());
       const ReturnNode& return_node = *sequence_node.NodeAt(0)->AsReturnNode();
       ASSERT(return_node.value()->IsLoadInstanceFieldNode());
       const LoadInstanceFieldNode& load_node =
           *return_node.value()->AsLoadInstanceFieldNode();
       // Only intrinsify getter if the field cannot contain a mutable double.
@@ skipping 656 matching lines @@
     case kUnboxedMint:
       return mint_class();
     default:
       UNREACHABLE();
       return Class::ZoneHandle();
   }
 }
 
 
 }  // namespace dart