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//===- llvm/Support/Casting.h - Allow flexible, checked, casts --*- 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
//
//===----------------------------------------------------------------------===//
//
// This file defines the isa<X>(), cast<X>(), dyn_cast<X>(),
// cast_if_present<X>(), and dyn_cast_if_present<X>() templates.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_CASTING_H
#define LLVM_SUPPORT_CASTING_H
#include "llvm/Support/Compiler.h"
#include "llvm/Support/type_traits.h"
#include <cassert>
#include <memory>
#include <optional>
#include <type_traits>
namespace llvm {
//===----------------------------------------------------------------------===//
// simplify_type
//===----------------------------------------------------------------------===//
/// Define a template that can be specialized by smart pointers to reflect the
/// fact that they are automatically dereferenced, and are not involved with the
/// template selection process... the default implementation is a noop.
// TODO: rename this and/or replace it with other cast traits.
template <typename From> struct simplify_type {
using SimpleType = From; // The real type this represents...
// An accessor to get the real value...
static SimpleType &getSimplifiedValue(From &Val) { return Val; }
};
template <typename From> struct simplify_type<const From> {
using NonConstSimpleType = typename simplify_type<From>::SimpleType;
using SimpleType = typename add_const_past_pointer<NonConstSimpleType>::type;
using RetType =
typename add_lvalue_reference_if_not_pointer<SimpleType>::type;
static RetType getSimplifiedValue(const From &Val) {
return simplify_type<From>::getSimplifiedValue(const_cast<From &>(Val));
}
};
// TODO: add this namespace once everyone is switched to using the new
// interface.
// namespace detail {
//===----------------------------------------------------------------------===//
// isa_impl
//===----------------------------------------------------------------------===//
// The core of the implementation of isa<X> is here; To and From should be
// the names of classes. This template can be specialized to customize the
// implementation of isa<> without rewriting it from scratch.
template <typename To, typename From, typename Enabler = void> struct isa_impl {
static inline bool doit(const From &Val) { return To::classof(&Val); }
};
// Always allow upcasts, and perform no dynamic check for them.
template <typename To, typename From>
struct isa_impl<To, From, std::enable_if_t<std::is_base_of_v<To, From>>> {
static inline bool doit(const From &) { return true; }
};
template <typename To, typename From> struct isa_impl_cl {
static inline bool doit(const From &Val) {
return isa_impl<To, From>::doit(Val);
}
};
template <typename To, typename From> struct isa_impl_cl<To, const From> {
static inline bool doit(const From &Val) {
return isa_impl<To, From>::doit(Val);
}
};
template <typename To, typename From>
struct isa_impl_cl<To, const std::unique_ptr<From>> {
static inline bool doit(const std::unique_ptr<From> &Val) {
assert(Val && "isa<> used on a null pointer");
return isa_impl_cl<To, From>::doit(*Val);
}
};
template <typename To, typename From> struct isa_impl_cl<To, From *> {
static inline bool doit(const From *Val) {
assert(Val && "isa<> used on a null pointer");
return isa_impl<To, From>::doit(*Val);
}
};
template <typename To, typename From> struct isa_impl_cl<To, From *const> {
static inline bool doit(const From *Val) {
assert(Val && "isa<> used on a null pointer");
return isa_impl<To, From>::doit(*Val);
}
};
template <typename To, typename From> struct isa_impl_cl<To, const From *> {
static inline bool doit(const From *Val) {
assert(Val && "isa<> used on a null pointer");
return isa_impl<To, From>::doit(*Val);
}
};
template <typename To, typename From>
struct isa_impl_cl<To, const From *const> {
static inline bool doit(const From *Val) {
assert(Val && "isa<> used on a null pointer");
return isa_impl<To, From>::doit(*Val);
}
};
template <typename To, typename From, typename SimpleFrom>
struct isa_impl_wrap {
// When From != SimplifiedType, we can simplify the type some more by using
// the simplify_type template.
static bool doit(const From &Val) {
return isa_impl_wrap<To, SimpleFrom,
typename simplify_type<SimpleFrom>::SimpleType>::
doit(simplify_type<const From>::getSimplifiedValue(Val));
}
};
template <typename To, typename FromTy>
struct isa_impl_wrap<To, FromTy, FromTy> {
// When From == SimpleType, we are as simple as we are going to get.
static bool doit(const FromTy &Val) {
return isa_impl_cl<To, FromTy>::doit(Val);
}
};
//===----------------------------------------------------------------------===//
// cast_retty + cast_retty_impl
//===----------------------------------------------------------------------===//
template <class To, class From> struct cast_retty;
// Calculate what type the 'cast' function should return, based on a requested
// type of To and a source type of From.
template <class To, class From> struct cast_retty_impl {
using ret_type = To &; // Normal case, return Ty&
};
template <class To, class From> struct cast_retty_impl<To, const From> {
using ret_type = const To &; // Normal case, return Ty&
};
template <class To, class From> struct cast_retty_impl<To, From *> {
using ret_type = To *; // Pointer arg case, return Ty*
};
template <class To, class From> struct cast_retty_impl<To, const From *> {
using ret_type = const To *; // Constant pointer arg case, return const Ty*
};
template <class To, class From> struct cast_retty_impl<To, const From *const> {
using ret_type = const To *; // Constant pointer arg case, return const Ty*
};
template <class To, class From>
struct cast_retty_impl<To, std::unique_ptr<From>> {
private:
using PointerType = typename cast_retty_impl<To, From *>::ret_type;
using ResultType = std::remove_pointer_t<PointerType>;
public:
using ret_type = std::unique_ptr<ResultType>;
};
template <class To, class From, class SimpleFrom> struct cast_retty_wrap {
// When the simplified type and the from type are not the same, use the type
// simplifier to reduce the type, then reuse cast_retty_impl to get the
// resultant type.
using ret_type = typename cast_retty<To, SimpleFrom>::ret_type;
};
template <class To, class FromTy> struct cast_retty_wrap<To, FromTy, FromTy> {
// When the simplified type is equal to the from type, use it directly.
using ret_type = typename cast_retty_impl<To, FromTy>::ret_type;
};
template <class To, class From> struct cast_retty {
using ret_type = typename cast_retty_wrap<
To, From, typename simplify_type<From>::SimpleType>::ret_type;
};
//===----------------------------------------------------------------------===//
// cast_convert_val
//===----------------------------------------------------------------------===//
// Ensure the non-simple values are converted using the simplify_type template
// that may be specialized by smart pointers...
//
template <class To, class From, class SimpleFrom> struct cast_convert_val {
// This is not a simple type, use the template to simplify it...
static typename cast_retty<To, From>::ret_type doit(const From &Val) {
return cast_convert_val<To, SimpleFrom,
typename simplify_type<SimpleFrom>::SimpleType>::
doit(simplify_type<From>::getSimplifiedValue(const_cast<From &>(Val)));
}
};
template <class To, class FromTy> struct cast_convert_val<To, FromTy, FromTy> {
// If it's a reference, switch to a pointer to do the cast and then deref it.
static typename cast_retty<To, FromTy>::ret_type doit(const FromTy &Val) {
return *(std::remove_reference_t<typename cast_retty<To, FromTy>::ret_type>
*)&const_cast<FromTy &>(Val);
}
};
template <class To, class FromTy>
struct cast_convert_val<To, FromTy *, FromTy *> {
// If it's a pointer, we can use c-style casting directly.
static typename cast_retty<To, FromTy *>::ret_type doit(const FromTy *Val) {
return (typename cast_retty<To, FromTy *>::ret_type) const_cast<FromTy *>(
Val);
}
};
//===----------------------------------------------------------------------===//
// is_simple_type
//===----------------------------------------------------------------------===//
template <class X> struct is_simple_type {
static const bool value =
std::is_same_v<X, typename simplify_type<X>::SimpleType>;
};
// } // namespace detail
//===----------------------------------------------------------------------===//
// CastIsPossible
//===----------------------------------------------------------------------===//
/// This struct provides a way to check if a given cast is possible. It provides
/// a static function called isPossible that is used to check if a cast can be
/// performed. It should be overridden like this:
///
/// template<> struct CastIsPossible<foo, bar> {
/// static inline bool isPossible(const bar &b) {
/// return bar.isFoo();
/// }
/// };
template <typename To, typename From, typename Enable = void>
struct CastIsPossible {
static inline bool isPossible(const From &f) {
return isa_impl_wrap<
To, const From,
typename simplify_type<const From>::SimpleType>::doit(f);
}
};
// Needed for optional unwrapping. This could be implemented with isa_impl, but
// we want to implement things in the new method and move old implementations
// over. In fact, some of the isa_impl templates should be moved over to
// CastIsPossible.
template <typename To, typename From>
struct CastIsPossible<To, std::optional<From>> {
static inline bool isPossible(const std::optional<From> &f) {
assert(f && "CastIsPossible::isPossible called on a nullopt!");
return isa_impl_wrap<
To, const From,
typename simplify_type<const From>::SimpleType>::doit(*f);
}
};
/// Upcasting (from derived to base) and casting from a type to itself should
/// always be possible.
template <typename To, typename From>
struct CastIsPossible<To, From, std::enable_if_t<std::is_base_of_v<To, From>>> {
static inline bool isPossible(const From &f) { return true; }
};
//===----------------------------------------------------------------------===//
// Cast traits
//===----------------------------------------------------------------------===//
/// All of these cast traits are meant to be implementations for useful casts
/// that users may want to use that are outside the standard behavior. An
/// example of how to use a special cast called `CastTrait` is:
///
/// template<> struct CastInfo<foo, bar> : public CastTrait<foo, bar> {};
///
/// Essentially, if your use case falls directly into one of the use cases
/// supported by a given cast trait, simply inherit your special CastInfo
/// directly from one of these to avoid having to reimplement the boilerplate
/// `isPossible/castFailed/doCast/doCastIfPossible`. A cast trait can also
/// provide a subset of those functions.
/// This cast trait just provides castFailed for the specified `To` type to make
/// CastInfo specializations more declarative. In order to use this, the target
/// result type must be `To` and `To` must be constructible from `nullptr`.
template <typename To> struct NullableValueCastFailed {
static To castFailed() { return To(nullptr); }
};
/// This cast trait just provides the default implementation of doCastIfPossible
/// to make CastInfo specializations more declarative. The `Derived` template
/// parameter *must* be provided for forwarding castFailed and doCast.
template <typename To, typename From, typename Derived>
struct DefaultDoCastIfPossible {
static To doCastIfPossible(From f) {
if (!Derived::isPossible(f))
return Derived::castFailed();
return Derived::doCast(f);
}
};
namespace detail {
/// A helper to derive the type to use with `Self` for cast traits, when the
/// provided CRTP derived type is allowed to be void.
template <typename OptionalDerived, typename Default>
using SelfType = std::conditional_t<std::is_same_v<OptionalDerived, void>,
Default, OptionalDerived>;
} // namespace detail
/// This cast trait provides casting for the specific case of casting to a
/// value-typed object from a pointer-typed object. Note that `To` must be
/// nullable/constructible from a pointer to `From` to use this cast.
template <typename To, typename From, typename Derived = void>
struct ValueFromPointerCast
: public CastIsPossible<To, From *>,
public NullableValueCastFailed<To>,
public DefaultDoCastIfPossible<
To, From *,
detail::SelfType<Derived, ValueFromPointerCast<To, From>>> {
static inline To doCast(From *f) { return To(f); }
};
/// This cast trait provides std::unique_ptr casting. It has the semantics of
/// moving the contents of the input unique_ptr into the output unique_ptr
/// during the cast. It's also a good example of how to implement a move-only
/// cast.
template <typename To, typename From, typename Derived = void>
struct UniquePtrCast : public CastIsPossible<To, From *> {
using Self = detail::SelfType<Derived, UniquePtrCast<To, From>>;
using CastResultType = std::unique_ptr<
std::remove_reference_t<typename cast_retty<To, From>::ret_type>>;
static inline CastResultType doCast(std::unique_ptr<From> &&f) {
return CastResultType((typename CastResultType::element_type *)f.release());
}
static inline CastResultType castFailed() { return CastResultType(nullptr); }
static inline CastResultType doCastIfPossible(std::unique_ptr<From> &f) {
if (!Self::isPossible(f.get()))
return castFailed();
return doCast(std::move(f));
}
};
/// This cast trait provides std::optional<T> casting. This means that if you
/// have a value type, you can cast it to another value type and have dyn_cast
/// return an std::optional<T>.
template <typename To, typename From, typename Derived = void>
struct OptionalValueCast
: public CastIsPossible<To, From>,
public DefaultDoCastIfPossible<
std::optional<To>, From,
detail::SelfType<Derived, OptionalValueCast<To, From>>> {
static inline std::optional<To> castFailed() { return std::optional<To>{}; }
static inline std::optional<To> doCast(const From &f) { return To(f); }
};
/// Provides a cast trait that strips `const` from types to make it easier to
/// implement a const-version of a non-const cast. It just removes boilerplate
/// and reduces the amount of code you as the user need to implement. You can
/// use it like this:
///
/// template<> struct CastInfo<foo, bar> {
/// ...verbose implementation...
/// };
///
/// template<> struct CastInfo<foo, const bar> : public
/// ConstStrippingForwardingCast<foo, const bar, CastInfo<foo, bar>> {};
///
template <typename To, typename From, typename ForwardTo>
struct ConstStrippingForwardingCast {
// Remove the pointer if it exists, then we can get rid of consts/volatiles.
using DecayedFrom = std::remove_cv_t<std::remove_pointer_t<From>>;
// Now if it's a pointer, add it back. Otherwise, we want a ref.
using NonConstFrom =
std::conditional_t<std::is_pointer_v<From>, DecayedFrom *, DecayedFrom &>;
static inline bool isPossible(const From &f) {
return ForwardTo::isPossible(const_cast<NonConstFrom>(f));
}
static inline decltype(auto) castFailed() { return ForwardTo::castFailed(); }
static inline decltype(auto) doCast(const From &f) {
return ForwardTo::doCast(const_cast<NonConstFrom>(f));
}
static inline decltype(auto) doCastIfPossible(const From &f) {
return ForwardTo::doCastIfPossible(const_cast<NonConstFrom>(f));
}
};
/// Provides a cast trait that uses a defined pointer to pointer cast as a base
/// for reference-to-reference casts. Note that it does not provide castFailed
/// and doCastIfPossible because a pointer-to-pointer cast would likely just
/// return `nullptr` which could cause nullptr dereference. You can use it like
/// this:
///
/// template <> struct CastInfo<foo, bar *> { ... verbose implementation... };
///
/// template <>
/// struct CastInfo<foo, bar>
/// : public ForwardToPointerCast<foo, bar, CastInfo<foo, bar *>> {};
///
template <typename To, typename From, typename ForwardTo>
struct ForwardToPointerCast {
static inline bool isPossible(const From &f) {
return ForwardTo::isPossible(&f);
}
static inline decltype(auto) doCast(const From &f) {
return *ForwardTo::doCast(&f);
}
};
//===----------------------------------------------------------------------===//
// CastInfo
//===----------------------------------------------------------------------===//
/// This struct provides a method for customizing the way a cast is performed.
/// It inherits from CastIsPossible, to support the case of declaring many
/// CastIsPossible specializations without having to specialize the full
/// CastInfo.
///
/// In order to specialize different behaviors, specify different functions in
/// your CastInfo specialization.
/// For isa<> customization, provide:
///
/// `static bool isPossible(const From &f)`
///
/// For cast<> customization, provide:
///
/// `static To doCast(const From &f)`
///
/// For dyn_cast<> and the *_if_present<> variants' customization, provide:
///
/// `static To castFailed()` and `static To doCastIfPossible(const From &f)`
///
/// Your specialization might look something like this:
///
/// template<> struct CastInfo<foo, bar> : public CastIsPossible<foo, bar> {
/// static inline foo doCast(const bar &b) {
/// return foo(const_cast<bar &>(b));
/// }
/// static inline foo castFailed() { return foo(); }
/// static inline foo doCastIfPossible(const bar &b) {
/// if (!CastInfo<foo, bar>::isPossible(b))
/// return castFailed();
/// return doCast(b);
/// }
/// };
// The default implementations of CastInfo don't use cast traits for now because
// we need to specify types all over the place due to the current expected
// casting behavior and the way cast_retty works. New use cases can and should
// take advantage of the cast traits whenever possible!
template <typename To, typename From, typename Enable = void>
struct CastInfo : public CastIsPossible<To, From> {
using Self = CastInfo<To, From, Enable>;
using CastReturnType = typename cast_retty<To, From>::ret_type;
static inline CastReturnType doCast(const From &f) {
return cast_convert_val<
To, From,
typename simplify_type<From>::SimpleType>::doit(const_cast<From &>(f));
}
// This assumes that you can construct the cast return type from `nullptr`.
// This is largely to support legacy use cases - if you don't want this
// behavior you should specialize CastInfo for your use case.
static inline CastReturnType castFailed() { return CastReturnType(nullptr); }
static inline CastReturnType doCastIfPossible(const From &f) {
if (!Self::isPossible(f))
return castFailed();
return doCast(f);
}
};
/// This struct provides an overload for CastInfo where From has simplify_type
/// defined. This simply forwards to the appropriate CastInfo with the
/// simplified type/value, so you don't have to implement both.
template <typename To, typename From>
struct CastInfo<To, From, std::enable_if_t<!is_simple_type<From>::value>> {
using Self = CastInfo<To, From>;
using SimpleFrom = typename simplify_type<From>::SimpleType;
using SimplifiedSelf = CastInfo<To, SimpleFrom>;
static inline bool isPossible(From &f) {
return SimplifiedSelf::isPossible(
simplify_type<From>::getSimplifiedValue(f));
}
static inline decltype(auto) doCast(From &f) {
return SimplifiedSelf::doCast(simplify_type<From>::getSimplifiedValue(f));
}
static inline decltype(auto) castFailed() {
return SimplifiedSelf::castFailed();
}
static inline decltype(auto) doCastIfPossible(From &f) {
return SimplifiedSelf::doCastIfPossible(
simplify_type<From>::getSimplifiedValue(f));
}
};
//===----------------------------------------------------------------------===//
// Pre-specialized CastInfo
//===----------------------------------------------------------------------===//
/// Provide a CastInfo specialized for std::unique_ptr.
template <typename To, typename From>
struct CastInfo<To, std::unique_ptr<From>> : public UniquePtrCast<To, From> {};
/// Provide a CastInfo specialized for std::optional<From>. It's assumed that if
/// the input is std::optional<From> that the output can be std::optional<To>.
/// If that's not the case, specialize CastInfo for your use case.
template <typename To, typename From>
struct CastInfo<To, std::optional<From>> : public OptionalValueCast<To, From> {
};
/// isa<X> - Return true if the parameter to the template is an instance of one
/// of the template type arguments. Used like this:
///
/// if (isa<Type>(myVal)) { ... }
/// if (isa<Type0, Type1, Type2>(myVal)) { ... }
template <typename To, typename From>
[[nodiscard]] inline bool isa(const From &Val) {
return CastInfo<To, const From>::isPossible(Val);
}
template <typename First, typename Second, typename... Rest, typename From>
[[nodiscard]] inline bool isa(const From &Val) {
return isa<First>(Val) || isa<Second, Rest...>(Val);
}
/// cast<X> - Return the argument parameter cast to the specified type. This
/// casting operator asserts that the type is correct, so it does not return
/// null on failure. It does not allow a null argument (use cast_if_present for
/// that). It is typically used like this:
///
/// cast<Instruction>(myVal)->getParent()
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) cast(const From &Val) {
assert(isa<To>(Val) && "cast<Ty>() argument of incompatible type!");
return CastInfo<To, const From>::doCast(Val);
}
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) cast(From &Val) {
assert(isa<To>(Val) && "cast<Ty>() argument of incompatible type!");
return CastInfo<To, From>::doCast(Val);
}
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) cast(From *Val) {
assert(isa<To>(Val) && "cast<Ty>() argument of incompatible type!");
return CastInfo<To, From *>::doCast(Val);
}
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) cast(std::unique_ptr<From> &&Val) {
assert(isa<To>(Val) && "cast<Ty>() argument of incompatible type!");
return CastInfo<To, std::unique_ptr<From>>::doCast(std::move(Val));
}
//===----------------------------------------------------------------------===//
// ValueIsPresent
//===----------------------------------------------------------------------===//
template <typename T>
constexpr bool IsNullable =
std::is_pointer_v<T> || std::is_constructible_v<T, std::nullptr_t>;
/// ValueIsPresent provides a way to check if a value is, well, present. For
/// pointers, this is the equivalent of checking against nullptr, for Optionals
/// this is the equivalent of checking hasValue(). It also provides a method for
/// unwrapping a value (think calling .value() on an optional).
// Generic values can't *not* be present.
template <typename T, typename Enable = void> struct ValueIsPresent {
using UnwrappedType = T;
static inline bool isPresent(const T &t) { return true; }
static inline decltype(auto) unwrapValue(T &t) { return t; }
};
// Optional provides its own way to check if something is present.
template <typename T> struct ValueIsPresent<std::optional<T>> {
using UnwrappedType = T;
static inline bool isPresent(const std::optional<T> &t) {
return t.has_value();
}
static inline decltype(auto) unwrapValue(std::optional<T> &t) { return *t; }
};
// If something is "nullable" then we just compare it to nullptr to see if it
// exists.
template <typename T>
struct ValueIsPresent<T, std::enable_if_t<IsNullable<T>>> {
using UnwrappedType = T;
static inline bool isPresent(const T &t) { return t != T(nullptr); }
static inline decltype(auto) unwrapValue(T &t) { return t; }
};
namespace detail {
// Convenience function we can use to check if a value is present. Because of
// simplify_type, we have to call it on the simplified type for now.
template <typename T> inline bool isPresent(const T &t) {
return ValueIsPresent<typename simplify_type<T>::SimpleType>::isPresent(
simplify_type<T>::getSimplifiedValue(const_cast<T &>(t)));
}
// Convenience function we can use to unwrap a value.
template <typename T> inline decltype(auto) unwrapValue(T &t) {
return ValueIsPresent<T>::unwrapValue(t);
}
} // namespace detail
/// dyn_cast<X> - Return the argument parameter cast to the specified type. This
/// casting operator returns null if the argument is of the wrong type, so it
/// can be used to test for a type as well as cast if successful. The value
/// passed in must be present, if not, use dyn_cast_if_present. This should be
/// used in the context of an if statement like this:
///
/// if (const Instruction *I = dyn_cast<Instruction>(myVal)) { ... }
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) dyn_cast(const From &Val) {
assert(detail::isPresent(Val) && "dyn_cast on a non-existent value");
return CastInfo<To, const From>::doCastIfPossible(Val);
}
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) dyn_cast(From &Val) {
assert(detail::isPresent(Val) && "dyn_cast on a non-existent value");
return CastInfo<To, From>::doCastIfPossible(Val);
}
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) dyn_cast(From *Val) {
assert(detail::isPresent(Val) && "dyn_cast on a non-existent value");
return CastInfo<To, From *>::doCastIfPossible(Val);
}
template <typename To, typename From>
[[nodiscard]] inline decltype(auto) dyn_cast(std::unique_ptr<From> &Val) {
assert(detail::isPresent(Val) && "dyn_cast on a non-existent value");
return CastInfo<To, std::unique_ptr<From>>::doCastIfPossible(Val);
}
/// isa_and_present<X> - Functionally identical to isa, except that a null value
/// is accepted.
template <typename... X, class Y>
[[nodiscard]] inline bool isa_and_present(const Y &Val) {
if (!detail::isPresent(Val))
return false;
return isa<X...>(Val);
}
template <typename... X, class Y>
[[nodiscard]] inline bool isa_and_nonnull(const Y &Val) {
return isa_and_present<X...>(Val);
}
/// cast_if_present<X> - Functionally identical to cast, except that a null
/// value is accepted.
template <class X, class Y>
[[nodiscard]] inline auto cast_if_present(const Y &Val) {
if (!detail::isPresent(Val))
return CastInfo<X, const Y>::castFailed();
assert(isa<X>(Val) && "cast_if_present<Ty>() argument of incompatible type!");
return cast<X>(detail::unwrapValue(Val));
}
template <class X, class Y> [[nodiscard]] inline auto cast_if_present(Y &Val) {
if (!detail::isPresent(Val))
return CastInfo<X, Y>::castFailed();
assert(isa<X>(Val) && "cast_if_present<Ty>() argument of incompatible type!");
return cast<X>(detail::unwrapValue(Val));
}
template <class X, class Y> [[nodiscard]] inline auto cast_if_present(Y *Val) {
if (!detail::isPresent(Val))
return CastInfo<X, Y *>::castFailed();
assert(isa<X>(Val) && "cast_if_present<Ty>() argument of incompatible type!");
return cast<X>(detail::unwrapValue(Val));
}
template <class X, class Y>
[[nodiscard]] inline auto cast_if_present(std::unique_ptr<Y> &&Val) {
if (!detail::isPresent(Val))
return UniquePtrCast<X, Y>::castFailed();
return UniquePtrCast<X, Y>::doCast(std::move(Val));
}
// Provide a forwarding from cast_or_null to cast_if_present for current
// users. This is deprecated and will be removed in a future patch, use
// cast_if_present instead.
template <class X, class Y> auto cast_or_null(const Y &Val) {
return cast_if_present<X>(Val);
}
template <class X, class Y> auto cast_or_null(Y &Val) {
return cast_if_present<X>(Val);
}
template <class X, class Y> auto cast_or_null(Y *Val) {
return cast_if_present<X>(Val);
}
template <class X, class Y> auto cast_or_null(std::unique_ptr<Y> &&Val) {
return cast_if_present<X>(std::move(Val));
}
/// dyn_cast_if_present<X> - Functionally identical to dyn_cast, except that a
/// null (or none in the case of optionals) value is accepted.
template <class X, class Y> auto dyn_cast_if_present(const Y &Val) {
if (!detail::isPresent(Val))
return CastInfo<X, const Y>::castFailed();
return CastInfo<X, const Y>::doCastIfPossible(detail::unwrapValue(Val));
}
template <class X, class Y> auto dyn_cast_if_present(Y &Val) {
if (!detail::isPresent(Val))
return CastInfo<X, Y>::castFailed();
return CastInfo<X, Y>::doCastIfPossible(detail::unwrapValue(Val));
}
template <class X, class Y> auto dyn_cast_if_present(Y *Val) {
if (!detail::isPresent(Val))
return CastInfo<X, Y *>::castFailed();
return CastInfo<X, Y *>::doCastIfPossible(detail::unwrapValue(Val));
}
// Forwards to dyn_cast_if_present to avoid breaking current users. This is
// deprecated and will be removed in a future patch, use
// cast_if_present instead.
template <class X, class Y> auto dyn_cast_or_null(const Y &Val) {
return dyn_cast_if_present<X>(Val);
}
template <class X, class Y> auto dyn_cast_or_null(Y &Val) {
return dyn_cast_if_present<X>(Val);
}
template <class X, class Y> auto dyn_cast_or_null(Y *Val) {
return dyn_cast_if_present<X>(Val);
}
/// unique_dyn_cast<X> - Given a unique_ptr<Y>, try to return a unique_ptr<X>,
/// taking ownership of the input pointer iff isa<X>(Val) is true. If the
/// cast is successful, From refers to nullptr on exit and the casted value
/// is returned. If the cast is unsuccessful, the function returns nullptr
/// and From is unchanged.
template <class X, class Y>
[[nodiscard]] inline typename CastInfo<X, std::unique_ptr<Y>>::CastResultType
unique_dyn_cast(std::unique_ptr<Y> &Val) {
if (!isa<X>(Val))
return nullptr;
return cast<X>(std::move(Val));
}
template <class X, class Y>
[[nodiscard]] inline auto unique_dyn_cast(std::unique_ptr<Y> &&Val) {
return unique_dyn_cast<X, Y>(Val);
}
// unique_dyn_cast_or_null<X> - Functionally identical to unique_dyn_cast,
// except that a null value is accepted.
template <class X, class Y>
[[nodiscard]] inline typename CastInfo<X, std::unique_ptr<Y>>::CastResultType
unique_dyn_cast_or_null(std::unique_ptr<Y> &Val) {
if (!Val)
return nullptr;
return unique_dyn_cast<X, Y>(Val);
}
template <class X, class Y>
[[nodiscard]] inline auto unique_dyn_cast_or_null(std::unique_ptr<Y> &&Val) {
return unique_dyn_cast_or_null<X, Y>(Val);
}
//===----------------------------------------------------------------------===//
// Isa Predicates
//===----------------------------------------------------------------------===//
/// These are wrappers over isa* function that allow them to be used in generic
/// algorithms such as `llvm:all_of`, `llvm::none_of`, etc. This is accomplished
/// by exposing the isa* functions through function objects with a generic
/// function call operator.
namespace detail {
template <typename... Types> struct IsaCheckPredicate {
template <typename T> [[nodiscard]] bool operator()(const T &Val) const {
return isa<Types...>(Val);
}
};
template <typename... Types> struct IsaAndPresentCheckPredicate {
template <typename T> [[nodiscard]] bool operator()(const T &Val) const {
return isa_and_present<Types...>(Val);
}
};
} // namespace detail
/// Function object wrapper for the `llvm::isa` type check. The function call
/// operator returns true when the value can be cast to any type in `Types`.
/// Example:
/// ```
/// SmallVector<Type> myTypes = ...;
/// if (llvm::all_of(myTypes, llvm::IsaPred<VectorType>))
/// ...
/// ```
template <typename... Types>
inline constexpr detail::IsaCheckPredicate<Types...> IsaPred{};
/// Function object wrapper for the `llvm::isa_and_present` type check. The
/// function call operator returns true when the value can be cast to any type
/// in `Types`, or if the value is not present (e.g., nullptr). Example:
/// ```
/// SmallVector<Type> myTypes = ...;
/// if (llvm::all_of(myTypes, llvm::IsaAndPresentPred<VectorType>))
/// ...
/// ```
template <typename... Types>
inline constexpr detail::IsaAndPresentCheckPredicate<Types...>
IsaAndPresentPred{};
} // end namespace llvm
#endif // LLVM_SUPPORT_CASTING_H
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