mirror of
https://github.com/c64scene-ar/llvm-6502.git
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7fe65d691d
As far as simplify_type is concerned, there are 3 kinds of smart pointers: * const correct: A 'const MyPtr<int> &' produces a 'const int*'. A 'MyPtr<int> &' produces a 'int *'. * always const: Even a 'MyPtr<int> &' produces a 'const int*'. * no const: Even a 'const MyPtr<int> &' produces a 'int*'. This patch then does the following: * Removes the unused specializations. Since they are unused, it is hard to know which kind should be implemented. * Make sure we don't drop const. * Fix the default forwarding so that const correct pointer only need one specialization. * Simplifies the existing specializations. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178147 91177308-0d34-0410-b5e6-96231b3b80d8
245 lines
9.5 KiB
C++
245 lines
9.5 KiB
C++
//===- llvm/Support/type_traits.h - Simplfied type traits -------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file provides a template class that determines if a type is a class or
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// not. The basic mechanism, based on using the pointer to member function of
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// a zero argument to a function was "boosted" from the boost type_traits
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// library. See http://www.boost.org/ for all the gory details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_TYPE_TRAITS_H
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#define LLVM_SUPPORT_TYPE_TRAITS_H
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#include "llvm/Support/DataTypes.h"
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#include <cstddef>
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#include <utility>
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#ifndef __has_feature
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#define LLVM_DEFINED_HAS_FEATURE
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#define __has_feature(x) 0
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#endif
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// This is actually the conforming implementation which works with abstract
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// classes. However, enough compilers have trouble with it that most will use
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// the one in boost/type_traits/object_traits.hpp. This implementation actually
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// works with VC7.0, but other interactions seem to fail when we use it.
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namespace llvm {
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namespace dont_use
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{
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// These two functions should never be used. They are helpers to
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// the is_class template below. They cannot be located inside
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// is_class because doing so causes at least GCC to think that
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// the value of the "value" enumerator is not constant. Placing
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// them out here (for some strange reason) allows the sizeof
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// operator against them to magically be constant. This is
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// important to make the is_class<T>::value idiom zero cost. it
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// evaluates to a constant 1 or 0 depending on whether the
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// parameter T is a class or not (respectively).
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template<typename T> char is_class_helper(void(T::*)());
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template<typename T> double is_class_helper(...);
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}
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template <typename T>
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struct is_class
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{
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// is_class<> metafunction due to Paul Mensonides (leavings@attbi.com). For
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// more details:
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// http://groups.google.com/groups?hl=en&selm=000001c1cc83%24e154d5e0%247772e50c%40c161550a&rnum=1
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public:
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static const bool value =
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sizeof(char) == sizeof(dont_use::is_class_helper<T>(0));
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};
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/// isPodLike - This is a type trait that is used to determine whether a given
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/// type can be copied around with memcpy instead of running ctors etc.
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template <typename T>
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struct isPodLike {
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#if __has_feature(is_trivially_copyable)
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// If the compiler supports the is_trivially_copyable trait use it, as it
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// matches the definition of isPodLike closely.
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static const bool value = __is_trivially_copyable(T);
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#else
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// If we don't know anything else, we can (at least) assume that all non-class
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// types are PODs.
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static const bool value = !is_class<T>::value;
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#endif
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};
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// std::pair's are pod-like if their elements are.
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template<typename T, typename U>
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struct isPodLike<std::pair<T, U> > {
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static const bool value = isPodLike<T>::value && isPodLike<U>::value;
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};
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template <class T, T v>
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struct integral_constant {
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typedef T value_type;
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static const value_type value = v;
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typedef integral_constant<T,v> type;
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operator value_type() { return value; }
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};
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typedef integral_constant<bool, true> true_type;
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typedef integral_constant<bool, false> false_type;
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/// \brief Metafunction that determines whether the two given types are
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/// equivalent.
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template<typename T, typename U> struct is_same : public false_type {};
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template<typename T> struct is_same<T, T> : public true_type {};
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/// \brief Metafunction that removes const qualification from a type.
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template <typename T> struct remove_const { typedef T type; };
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template <typename T> struct remove_const<const T> { typedef T type; };
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/// \brief Metafunction that removes volatile qualification from a type.
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template <typename T> struct remove_volatile { typedef T type; };
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template <typename T> struct remove_volatile<volatile T> { typedef T type; };
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/// \brief Metafunction that removes both const and volatile qualification from
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/// a type.
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template <typename T> struct remove_cv {
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typedef typename remove_const<typename remove_volatile<T>::type>::type type;
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};
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/// \brief Helper to implement is_integral metafunction.
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template <typename T> struct is_integral_impl : false_type {};
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template <> struct is_integral_impl< bool> : true_type {};
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template <> struct is_integral_impl< char> : true_type {};
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template <> struct is_integral_impl< signed char> : true_type {};
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template <> struct is_integral_impl<unsigned char> : true_type {};
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template <> struct is_integral_impl< wchar_t> : true_type {};
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template <> struct is_integral_impl< short> : true_type {};
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template <> struct is_integral_impl<unsigned short> : true_type {};
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template <> struct is_integral_impl< int> : true_type {};
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template <> struct is_integral_impl<unsigned int> : true_type {};
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template <> struct is_integral_impl< long> : true_type {};
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template <> struct is_integral_impl<unsigned long> : true_type {};
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template <> struct is_integral_impl< long long> : true_type {};
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template <> struct is_integral_impl<unsigned long long> : true_type {};
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/// \brief Metafunction that determines whether the given type is an integral
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/// type.
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template <typename T>
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struct is_integral : is_integral_impl<T> {};
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/// \brief Metafunction to remove reference from a type.
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template <typename T> struct remove_reference { typedef T type; };
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template <typename T> struct remove_reference<T&> { typedef T type; };
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/// \brief Metafunction that determines whether the given type is a pointer
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/// type.
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template <typename T> struct is_pointer : false_type {};
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template <typename T> struct is_pointer<T*> : true_type {};
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template <typename T> struct is_pointer<T* const> : true_type {};
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template <typename T> struct is_pointer<T* volatile> : true_type {};
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template <typename T> struct is_pointer<T* const volatile> : true_type {};
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/// \brief Metafunction that determines wheather the given type is a reference.
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template <typename T> struct is_reference : false_type {};
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template <typename T> struct is_reference<T&> : true_type {};
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/// \brief Metafunction that determines whether the given type is either an
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/// integral type or an enumeration type.
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///
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/// Note that this accepts potentially more integral types than we whitelist
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/// above for is_integral because it is based on merely being convertible
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/// implicitly to an integral type.
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template <typename T> class is_integral_or_enum {
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// Provide an overload which can be called with anything implicitly
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// convertible to an unsigned long long. This should catch integer types and
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// enumeration types at least. We blacklist classes with conversion operators
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// below.
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static double check_int_convertible(unsigned long long);
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static char check_int_convertible(...);
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typedef typename remove_reference<T>::type UnderlyingT;
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static UnderlyingT &nonce_instance;
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public:
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static const bool
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value = (!is_class<UnderlyingT>::value && !is_pointer<UnderlyingT>::value &&
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!is_same<UnderlyingT, float>::value &&
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!is_same<UnderlyingT, double>::value &&
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sizeof(char) != sizeof(check_int_convertible(nonce_instance)));
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};
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// enable_if_c - Enable/disable a template based on a metafunction
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template<bool Cond, typename T = void>
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struct enable_if_c {
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typedef T type;
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};
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template<typename T> struct enable_if_c<false, T> { };
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// enable_if - Enable/disable a template based on a metafunction
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template<typename Cond, typename T = void>
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struct enable_if : public enable_if_c<Cond::value, T> { };
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namespace dont_use {
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template<typename Base> char base_of_helper(const volatile Base*);
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template<typename Base> double base_of_helper(...);
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}
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/// is_base_of - Metafunction to determine whether one type is a base class of
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/// (or identical to) another type.
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template<typename Base, typename Derived>
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struct is_base_of {
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static const bool value
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= is_class<Base>::value && is_class<Derived>::value &&
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sizeof(char) == sizeof(dont_use::base_of_helper<Base>((Derived*)0));
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};
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// remove_pointer - Metafunction to turn Foo* into Foo. Defined in
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// C++0x [meta.trans.ptr].
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template <typename T> struct remove_pointer { typedef T type; };
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template <typename T> struct remove_pointer<T*> { typedef T type; };
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template <typename T> struct remove_pointer<T*const> { typedef T type; };
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template <typename T> struct remove_pointer<T*volatile> { typedef T type; };
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template <typename T> struct remove_pointer<T*const volatile> {
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typedef T type; };
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// If T is a pointer, just return it. If it is not, return T&.
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template<typename T, typename Enable = void>
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struct add_lvalue_reference_if_not_pointer { typedef T &type; };
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template<typename T>
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struct add_lvalue_reference_if_not_pointer<T,
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typename enable_if<is_pointer<T> >::type> {
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typedef T type;
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};
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// If T is a pointer to X, return a pointer to const X. If it is not, return
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// const T.
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template<typename T, typename Enable = void>
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struct add_const_past_pointer { typedef const T type; };
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template<typename T>
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struct add_const_past_pointer<T, typename enable_if<is_pointer<T> >::type> {
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typedef const typename remove_pointer<T>::type *type;
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};
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template <bool, typename T, typename F>
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struct conditional { typedef T type; };
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template <typename T, typename F>
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struct conditional<false, T, F> { typedef F type; };
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}
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#ifdef LLVM_DEFINED_HAS_FEATURE
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#undef __has_feature
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#endif
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#endif
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