Split GuardField into GuardFieldType and GuardFieldLength instructions.

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 3156 matching lines @@
   if (FLAG_enable_type_checks) {
     const AbstractType& type = AbstractType::ZoneHandle(node->field().type());
     const String& dst_name = String::ZoneHandle(node->field().name());
     store_value = BuildAssignableValue(node->value()->token_pos(),
                                        store_value,
                                        type,
                                        dst_name);
   }
 
   store_value = Bind(BuildStoreExprTemp(store_value));
-  GuardFieldInstr* guard =
-      new GuardFieldInstr(store_value,
-                          node->field(),
-                          Isolate::Current()->GetNextDeoptId());
-  AddInstruction(guard);
+  GuardFieldClassInstr* guard_field_class =
+      new GuardFieldClassInstr(store_value,
+                               node->field(),
+                               Isolate::Current()->GetNextDeoptId());
+  AddInstruction(guard_field_class);
+
+  store_value = Bind(BuildLoadExprTemp());
+  GuardFieldLengthInstr* guard_field_length =
+      new GuardFieldLengthInstr(store_value,
+                                node->field(),
+                                Isolate::Current()->GetNextDeoptId());
+  AddInstruction(guard_field_length);
+
 
   store_value = Bind(BuildLoadExprTemp());
   StoreInstanceFieldInstr* store =
       new StoreInstanceFieldInstr(node->field(),
                                   for_instance.value(),
                                   store_value,
                                   kEmitStoreBarrier,
                                   node->token_pos());
   store->set_is_initialization(true);  // Maybe initializing store.
   ReturnDefinition(store);
@@ skipping 776 matching lines @@
                                   LanguageError::kBailout,
                                   Heap::kNew,
                                   "FlowGraphBuilder Bailout: %s %s",
                                   String::Handle(function.name()).ToCString(),
                                   reason));
   Isolate::Current()->long_jump_base()->Jump(1, error);
   UNREACHABLE();
 }
 
 }  // namespace dart