Map deleted enum values to a sentinel value.

runtime/vm/parser.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/parser.h"
 #include "vm/flags.h"
 
 #ifndef DART_PRECOMPILED_RUNTIME
 
 #include "lib/invocation_mirror.h"
@@ skipping 4847 matching lines @@
   Field& values_field = Field::ZoneHandle(Z);
   values_field =
       Field::New(Symbols::Values(),
                  /* is_static = */ true,
                  /* is_final = */ true,
                  /* is_const = */ true,
                  /* is_reflectable = */ true, cls,
                  Type::Handle(Z, Type::ArrayType()), cls.token_pos());
   enum_members.AddField(values_field);
 
+  // Add static field 'const _deleted_enum_sentinel'.
+  Field& deleted_enum_sentinel = Field::ZoneHandle(Z);
+  deleted_enum_sentinel =
+      Field::New(Symbols::_DeletedEnumSentinel(),
+                 /* is_static = */ true,
+                 /* is_final = */ true,
+                 /* is_const = */ true,
+                 /* is_reflectable = */ false, cls,
+                 Type::Handle(Z, Type::ArrayType()), cls.token_pos());

[siva, 2016/11/14 22:18:23]

Type::Handle(Z, Type::ArrayType()) could be hoisted out from the two Field::New
calls.

Also we could hoist this above and use values_field handle for both cases.

[Cutch, 2016/11/15 22:13:55]

Done.

+  enum_members.AddField(deleted_enum_sentinel);
+
   // Allocate the immutable array containing the enumeration values.
   // The actual enum instance values will be patched in later.
   const Array& values_array = Array::Handle(Z, Array::New(i, Heap::kOld));
   values_field.SetStaticValue(values_array, true);
   values_field.RecordStore(values_array);
 
   // Clone the _name field from the helper class.
   Field& _name_field = Field::Handle(
       Z, helper_class.LookupInstanceFieldAllowPrivate(Symbols::_name()));
   ASSERT(!_name_field.IsNull());
@@ skipping 9628 matching lines @@
     const ArgumentListNode& function_args,
     const LocalVariable* temp_for_last_arg,
     bool is_super_invocation) {
   UNREACHABLE();
   return NULL;
 }
 
 }  // namespace dart
 
 #endif  // DART_PRECOMPILED_RUNTIME