// SPDX-License-Identifier: GPL-3.0-or-later

#ifndef RCC_CODEGEN_GLOBALISEL_LEGALIZERINFO_H
#define RCC_CODEGEN_GLOBALISEL_LEGALIZERINFO_H

#include "rcc/Support/Error.h"

#include <cstdint>

namespace rcc {

class MachineFunction;
class MachineInstr;
class TargetDescription;

enum class LegalizationAction : std::uint8_t {
  Legal,
  Unsupported,
  Custom,
  Lower,
  Libcall,
  WidenScalar,
  NarrowScalar,
  MoreElements,
  FewerElements,
  Bitcast,
  ChangeElementType,
  ChangeAddressSpace,
};

class LegalizerInfo {
public:
  virtual ~LegalizerInfo() = default;

  [[nodiscard]] virtual Expected<LegalizationAction>
  classify(const MachineInstr &Instruction, const MachineFunction &Function,
           const TargetDescription &Target) const = 0;

  [[nodiscard]] virtual Expected<void> lower(MachineInstr &Instruction, MachineFunction &Function,
                                             const TargetDescription &Target,
                                             LegalizationAction Action) const = 0;

  // This hook performs read-only target checks before a lowering mutation is committed.
  [[nodiscard]] virtual Expected<void> validateLowering(const MachineInstr &,
                                                        const MachineFunction &,
                                                        const TargetDescription &,
                                                        LegalizationAction) const {
    return {};
  }
};

} // namespace rcc

#endif // RCC_CODEGEN_GLOBALISEL_LEGALIZERINFO_H