// Copyright 2025 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_CODEGEN_CONSTANT_POOL_ENTRY_H_
#define V8_CODEGEN_CONSTANT_POOL_ENTRY_H_

#include "src/base/numbers/double.h"
#include "src/codegen/reloc-info.h"
#include "src/common/globals.h"

namespace v8 {
namespace internal {

// -----------------------------------------------------------------------------
// Constant pool support

class ConstantPoolEntry {
 public:
  ConstantPoolEntry() = default;
  ConstantPoolEntry(int position, intptr_t value, bool sharing_ok,
                    RelocInfo::Mode rmode = RelocInfo::NO_INFO)
      : position_(position),
        merged_index_(sharing_ok ? SHARING_ALLOWED : SHARING_PROHIBITED),
        value_(value),
        rmode_(rmode) {}
  ConstantPoolEntry(int position, base::Double value,
                    RelocInfo::Mode rmode = RelocInfo::NO_INFO)
      : position_(position),
        merged_index_(SHARING_ALLOWED),
        value64_(value.AsUint64()),
        rmode_(rmode) {}

  int position() const { return position_; }
  bool sharing_ok() const { return merged_index_ != SHARING_PROHIBITED; }
  bool is_merged() const { return merged_index_ >= 0; }
  int merged_index() const {
    DCHECK(is_merged());
    return merged_index_;
  }
  void set_merged_index(int index) {
    DCHECK(sharing_ok());
    merged_index_ = index;
    DCHECK(is_merged());
  }
  int offset() const {
    DCHECK_GE(merged_index_, 0);
    return merged_index_;
  }
  void set_offset(int offset) {
    DCHECK_GE(offset, 0);
    merged_index_ = offset;
  }
  intptr_t value() const { return value_; }
  uint64_t value64() const { return value64_; }
  RelocInfo::Mode rmode() const { return rmode_; }

  enum Type { INTPTR, DOUBLE, NUMBER_OF_TYPES };

  static int size(Type type) {
    return (type == INTPTR) ? kSystemPointerSize : kDoubleSize;
  }

  enum Access { REGULAR, OVERFLOWED };

 private:
  int position_;
  int merged_index_;
  union {
    intptr_t value_;
    uint64_t value64_;
  };
  // TODO(leszeks): The way we use this, it could probably be packed into
  // merged_index_ if size is a concern.
  RelocInfo::Mode rmode_;
  enum { SHARING_PROHIBITED = -2, SHARING_ALLOWED = -1 };
};

}  // namespace internal
}  // namespace v8

#endif  // V8_CODEGEN_CONSTANT_POOL_ENTRY_H_