//===- Types.h - MLIR Type Classes ------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef MLIR_IR_TYPES_H
#define MLIR_IR_TYPES_H

#include "mlir/IR/TypeSupport.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/Support/PointerLikeTypeTraits.h"

namespace mlir {
/// Instances of the Type class are uniqued, have an immutable identifier and an
/// optional mutable component.  They wrap a pointer to the storage object owned
/// by MLIRContext.  Therefore, instances of Type are passed around by value.
///
/// Some types are "primitives" meaning they do not have any parameters, for
/// example the Index type.  Parametric types have additional information that
/// differentiates the types of the same class, for example the Integer type has
/// bitwidth, making i8 and i16 belong to the same kind by be different
/// instances of the IntegerType. Type parameters are part of the unique
/// immutable key.  The mutable component of the type can be modified after the
/// type is created, but cannot affect the identity of the type.
///
/// Types are constructed and uniqued via the 'detail::TypeUniquer' class.
///
/// Derived type classes are expected to implement several required
/// implementation hooks:
///  * Optional:
///    - static LogicalResult verify(
///                                function_ref<InFlightDiagnostic()> emitError,
///                                Args... args)
///      * This method is invoked when calling the 'TypeBase::get/getChecked'
///        methods to ensure that the arguments passed in are valid to construct
///        a type instance with.
///      * This method is expected to return failure if a type cannot be
///        constructed with 'args', success otherwise.
///      * 'args' must correspond with the arguments passed into the
///        'TypeBase::get' call.
///
///
/// Type storage objects inherit from TypeStorage and contain the following:
///    - The dialect that defined the type.
///    - Any parameters of the type.
///    - An optional mutable component.
/// For non-parametric types, a convenience DefaultTypeStorage is provided.
/// Parametric storage types must derive TypeStorage and respect the following:
///    - Define a type alias, KeyTy, to a type that uniquely identifies the
///      instance of the type.
///      * The key type must be constructible from the values passed into the
///        detail::TypeUniquer::get call.
///      * If the KeyTy does not have an llvm::DenseMapInfo specialization, the
///        storage class must define a hashing method:
///         'static unsigned hashKey(const KeyTy &)'
///
///    - Provide a method, 'bool operator==(const KeyTy &) const', to
///      compare the storage instance against an instance of the key type.
///
///    - Provide a static construction method:
///        'DerivedStorage *construct(TypeStorageAllocator &, const KeyTy &key)'
///      that builds a unique instance of the derived storage. The arguments to
///      this function are an allocator to store any uniqued data within the
///      context and the key type for this storage.
///
///    - If they have a mutable component, this component must not be a part of
//       the key.
class Type {
public:
  /// Utility class for implementing types.
  template <typename ConcreteType, typename BaseType, typename StorageType,
            template <typename T> class... Traits>
  using TypeBase = detail::StorageUserBase<ConcreteType, BaseType, StorageType,
                                           detail::TypeUniquer, Traits...>;

  using ImplType = TypeStorage;

  using AbstractTy = AbstractType;

  constexpr Type() : impl(nullptr) {}
  /* implicit */ Type(const ImplType *impl)
      : impl(const_cast<ImplType *>(impl)) {}

  Type(const Type &other) = default;
  Type &operator=(const Type &other) = default;

  bool operator==(Type other) const { return impl == other.impl; }
  bool operator!=(Type other) const { return !(*this == other); }
  explicit operator bool() const { return impl; }

  bool operator!() const { return impl == nullptr; }

  template <typename U> bool isa() const;
  template <typename First, typename Second, typename... Rest> bool isa() const;
  template <typename U> U dyn_cast() const;
  template <typename U> U dyn_cast_or_null() const;
  template <typename U> U cast() const;

  // Support type casting Type to itself.
  static bool classof(Type) { return true; }

  /// Return a unique identifier for the concrete type. This is used to support
  /// dynamic type casting.
  TypeID getTypeID() { return impl->getAbstractType().getTypeID(); }

  /// Return the MLIRContext in which this type was uniqued.
  MLIRContext *getContext() const;

  /// Get the dialect this type is registered to.
  Dialect &getDialect() const { return impl->getAbstractType().getDialect(); }

  // Convenience predicates.  This is only for floating point types,
  // derived types should use isa/dyn_cast.
  bool isIndex() const;
  bool isBF16() const;
  bool isF16() const;
  bool isF32() const;
  bool isF64() const;
  bool isF80() const;
  bool isF128() const;

  /// Return true if this is an integer type with the specified width.
  bool isInteger(unsigned width) const;
  /// Return true if this is a signless integer type (with the specified width).
  bool isSignlessInteger() const;
  bool isSignlessInteger(unsigned width) const;
  /// Return true if this is a signed integer type (with the specified width).
  bool isSignedInteger() const;
  bool isSignedInteger(unsigned width) const;
  /// Return true if this is an unsigned integer type (with the specified
  /// width).
  bool isUnsignedInteger() const;
  bool isUnsignedInteger(unsigned width) const;

  /// Return the bit width of an integer or a float type, assert failure on
  /// other types.
  unsigned getIntOrFloatBitWidth() const;

  /// Return true if this is a signless integer or index type.
  bool isSignlessIntOrIndex() const;
  /// Return true if this is a signless integer, index, or float type.
  bool isSignlessIntOrIndexOrFloat() const;
  /// Return true of this is a signless integer or a float type.
  bool isSignlessIntOrFloat() const;

  /// Return true if this is an integer (of any signedness) or an index type.
  bool isIntOrIndex() const;
  /// Return true if this is an integer (of any signedness) or a float type.
  bool isIntOrFloat() const;
  /// Return true if this is an integer (of any signedness), index, or float
  /// type.
  bool isIntOrIndexOrFloat() const;

  /// Print the current type.
  void print(raw_ostream &os) const;
  void dump() const;

  friend ::llvm::hash_code hash_value(Type arg);

  /// Methods for supporting PointerLikeTypeTraits.
  const void *getAsOpaquePointer() const {
    return static_cast<const void *>(impl);
  }
  static Type getFromOpaquePointer(const void *pointer) {
    return Type(reinterpret_cast<ImplType *>(const_cast<void *>(pointer)));
  }

  /// Returns true if the type was registered with a particular trait.
  template <template <typename T> class Trait>
  bool hasTrait() {
    return getAbstractType().hasTrait<Trait>();
  }

  /// Return the abstract type descriptor for this type.
  const AbstractTy &getAbstractType() { return impl->getAbstractType(); }

protected:
  ImplType *impl;
};

inline raw_ostream &operator<<(raw_ostream &os, Type type) {
  type.print(os);
  return os;
}

//===----------------------------------------------------------------------===//
// TypeTraitBase
//===----------------------------------------------------------------------===//

namespace TypeTrait {
/// This class represents the base of a type trait.
template <typename ConcreteType, template <typename> class TraitType>
using TraitBase = detail::StorageUserTraitBase<ConcreteType, TraitType>;
} // namespace TypeTrait

//===----------------------------------------------------------------------===//
// TypeInterface
//===----------------------------------------------------------------------===//

/// This class represents the base of a type interface. See the definition  of
/// `detail::Interface` for requirements on the `Traits` type.
template <typename ConcreteType, typename Traits>
class TypeInterface : public detail::Interface<ConcreteType, Type, Traits, Type,
                                               TypeTrait::TraitBase> {
public:
  using Base = TypeInterface<ConcreteType, Traits>;
  using InterfaceBase =
      detail::Interface<ConcreteType, Type, Traits, Type, TypeTrait::TraitBase>;
  using InterfaceBase::InterfaceBase;

private:
  /// Returns the impl interface instance for the given type.
  static typename InterfaceBase::Concept *getInterfaceFor(Type type) {
    return type.getAbstractType().getInterface<ConcreteType>();
  }

  /// Allow access to 'getInterfaceFor'.
  friend InterfaceBase;
};

//===----------------------------------------------------------------------===//
// Type Utils
//===----------------------------------------------------------------------===//

// Make Type hashable.
inline ::llvm::hash_code hash_value(Type arg) {
  return DenseMapInfo<const Type::ImplType *>::getHashValue(arg.impl);
}

template <typename U> bool Type::isa() const {
  assert(impl && "isa<> used on a null type.");
  return U::classof(*this);
}

template <typename First, typename Second, typename... Rest>
bool Type::isa() const {
  return isa<First>() || isa<Second, Rest...>();
}

template <typename U> U Type::dyn_cast() const {
  return isa<U>() ? U(impl) : U(nullptr);
}
template <typename U> U Type::dyn_cast_or_null() const {
  return (impl && isa<U>()) ? U(impl) : U(nullptr);
}
template <typename U> U Type::cast() const {
  assert(isa<U>());
  return U(impl);
}

} // end namespace mlir

namespace llvm {

// Type hash just like pointers.
template <> struct DenseMapInfo<mlir::Type> {
  static mlir::Type getEmptyKey() {
    auto pointer = llvm::DenseMapInfo<void *>::getEmptyKey();
    return mlir::Type(static_cast<mlir::Type::ImplType *>(pointer));
  }
  static mlir::Type getTombstoneKey() {
    auto pointer = llvm::DenseMapInfo<void *>::getTombstoneKey();
    return mlir::Type(static_cast<mlir::Type::ImplType *>(pointer));
  }
  static unsigned getHashValue(mlir::Type val) { return mlir::hash_value(val); }
  static bool isEqual(mlir::Type LHS, mlir::Type RHS) { return LHS == RHS; }
};
template <typename T>
struct DenseMapInfo<T, std::enable_if_t<std::is_base_of<mlir::Type, T>::value>>
    : public DenseMapInfo<mlir::Type> {
  static T getEmptyKey() {
    const void *pointer = llvm::DenseMapInfo<const void *>::getEmptyKey();
    return T::getFromOpaquePointer(pointer);
  }
  static T getTombstoneKey() {
    const void *pointer = llvm::DenseMapInfo<const void *>::getTombstoneKey();
    return T::getFromOpaquePointer(pointer);
  }
};

/// We align TypeStorage by 8, so allow LLVM to steal the low bits.
template <> struct PointerLikeTypeTraits<mlir::Type> {
public:
  static inline void *getAsVoidPointer(mlir::Type I) {
    return const_cast<void *>(I.getAsOpaquePointer());
  }
  static inline mlir::Type getFromVoidPointer(void *P) {
    return mlir::Type::getFromOpaquePointer(P);
  }
  static constexpr int NumLowBitsAvailable = 3;
};

} // namespace llvm

#endif // MLIR_IR_TYPES_H