Make cycle checking of super interfaces linear instead of quadratic by marking

runtime/vm/object.h

 // 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.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 974 matching lines @@
   bool is_mixin_type_applied() const {
     return MixinTypeAppliedBit::decode(raw_ptr()->state_bits_);
   }
   void set_is_mixin_type_applied() const;
 
   bool is_fields_marked_nullable() const {
     return FieldsMarkedNullableBit::decode(raw_ptr()->state_bits_);
   }
   void set_is_fields_marked_nullable() const;
 
+  bool is_cycle_free() const {
+    return CycleFreeBit::decode(raw_ptr()->state_bits_);
+  }
+  void set_is_cycle_free() const;
+
   uint16_t num_native_fields() const {
     return raw_ptr()->num_native_fields_;
   }
   void set_num_native_fields(uint16_t value) const {
     raw_ptr()->num_native_fields_ = value;
   }
 
   RawCode* allocation_stub() const {
     return raw_ptr()->allocation_stub_;
   }
@@ skipping 88 matching lines @@
     kTypeFinalizedBit = 2,
     kClassFinalizedBits = 3,
     kClassFinalizedSize = 2,
     kAbstractBit = 5,
     kPatchBit = 6,
     kSynthesizedClassBit = 7,
     kMarkedForParsingBit = 8,
     kMixinAppAliasBit = 9,
     kMixinTypeAppliedBit = 10,
     kFieldsMarkedNullableBit = 11,
+    kCycleFreeBit = 12,
   };
   class ConstBit : public BitField<bool, kConstBit, 1> {};
   class ImplementedBit : public BitField<bool, kImplementedBit, 1> {};
   class TypeFinalizedBit : public BitField<bool, kTypeFinalizedBit, 1> {};
   class ClassFinalizedBits : public BitField<RawClass::ClassFinalizedState,
       kClassFinalizedBits, kClassFinalizedSize> {};  // NOLINT
   class AbstractBit : public BitField<bool, kAbstractBit, 1> {};
   class PatchBit : public BitField<bool, kPatchBit, 1> {};
   class SynthesizedClassBit : public BitField<bool, kSynthesizedClassBit, 1> {};
   class MarkedForParsingBit : public BitField<bool, kMarkedForParsingBit, 1> {};
   class MixinAppAliasBit : public BitField<bool, kMixinAppAliasBit, 1> {};
   class MixinTypeAppliedBit : public BitField<bool, kMixinTypeAppliedBit, 1> {};
   class FieldsMarkedNullableBit : public BitField<bool,
       kFieldsMarkedNullableBit, 1> {};  // NOLINT
+  class CycleFreeBit : public BitField<bool, kCycleFreeBit, 1> {};
 
   void set_name(const String& value) const;
   void set_user_name(const String& value) const;
   RawString* GenerateUserVisibleName() const;
   void set_signature_function(const Function& value) const;
   void set_signature_type(const AbstractType& value) const;
   void set_state_bits(intptr_t bits) const;
 
   void set_constants(const Array& value) const;
 
@@ skipping 5484 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_