feedback-cell.h

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// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef V8_OBJECTS_FEEDBACK_CELL_H_
#define V8_OBJECTS_FEEDBACK_CELL_H_
 
#include <optional>
 
#include "src/objects/struct.h"
 
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
 
namespace v8::internal {
 
class Undefined;
 
#include "torque-generated/src/objects/feedback-cell-tq.inc"
 
// This is a special cell used to maintain both the link between a
// closure and its feedback vector, as well as a way to count the
// number of closures created for a certain function per native
// context. There's at most one FeedbackCell for each function in
// a native context.
class FeedbackCell : public TorqueGeneratedFeedbackCell<FeedbackCell, Struct> {
 public:
  // Dispatched behavior.
  DECL_PRINTER(FeedbackCell)
 
  static const int kUnalignedSize = kSize;
  static const int kAlignedSize = RoundUp<kObjectAlignment>(int{kSize});
 
  using TorqueGeneratedFeedbackCell<FeedbackCell, Struct>::value;
  using TorqueGeneratedFeedbackCell<FeedbackCell, Struct>::set_value;
 
  DECL_RELEASE_ACQUIRE_ACCESSORS(value, Tagged<HeapObject>)
 
  inline void clear_interrupt_budget();
  inline void clear_dispatch_handle();
 
#ifdef V8_ENABLE_LEAPTIERING
  inline JSDispatchHandle dispatch_handle() const;
  inline void set_dispatch_handle(JSDispatchHandle new_handle);
#endif  // V8_ENABLE_LEAPTIERING
 
  inline void clear_padding();
  inline void reset_feedback_vector(
      std::optional<
          std::function<void(Tagged<HeapObject> object, ObjectSlot slot,
                             Tagged<HeapObject> target)>>
          gc_notify_updated_slot = std::nullopt);
 
  enum ClosureCountTransition { kNoneToOne, kOneToMany, kMany };
  // The closure count is encoded in the cell's map, which distinguishes
  // between zero, one, or many closures. This function records a new closure
  // creation by updating the map.
  inline ClosureCountTransition IncrementClosureCount(Isolate* isolate);
 
  DECL_VERIFIER(FeedbackCell)
 
  class BodyDescriptor;
 
  TQ_OBJECT_CONSTRUCTORS(FeedbackCell)
};
 
}  // namespace v8::internal
 
#include "src/objects/object-macros-undef.h"
 
#endif  // V8_OBJECTS_FEEDBACK_CELL_H_