include/llvm/ADT/DenseMapInfo.h - llvm-project/llvm - Git at Google

 //===- llvm/ADT/DenseMapInfo.h - Type traits for DenseMap -------*- 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
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// This file defines DenseMapInfo traits for DenseMap.
 ///
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_ADT_DENSEMAPINFO_H
 #define LLVM_ADT_DENSEMAPINFO_H

 #include <cassert>
 #include <cstddef>
 #include <cstdint>
 #include <tuple>
 #include <type_traits>
 #include <utility>
 #include <variant>

 namespace llvm {

 namespace detail {

 /// Simplistic combination of 32-bit hash values into 32-bit hash values.
 static inline unsigned combineHashValue(unsigned a, unsigned b) {
   uint64_t key = (uint64_t)a << 32 | (uint64_t)b;
   key += ~(key << 32);
   key ^= (key >> 22);
   key += ~(key << 13);
   key ^= (key >> 8);
   key += (key << 3);
   key ^= (key >> 15);
   key += ~(key << 27);
   key ^= (key >> 31);
   return (unsigned)key;
 }

 } // end namespace detail

 /// An information struct used to provide DenseMap with the various necessary
 /// components for a given value type `T`. `Enable` is an optional additional
 /// parameter that is used to support SFINAE (generally using std::enable_if_t)
 /// in derived DenseMapInfo specializations; in non-SFINAE use cases this should
 /// just be `void`.
 template<typename T, typename Enable = void>
 struct DenseMapInfo {
   //static inline T getEmptyKey();
   //static inline T getTombstoneKey();
   //static unsigned getHashValue(const T &Val);
   //static bool isEqual(const T &LHS, const T &RHS);
 };

 // Provide DenseMapInfo for all pointers. Come up with sentinel pointer values
 // that are aligned to alignof(T) bytes, but try to avoid requiring T to be
 // complete. This allows clients to instantiate DenseMap<T*, ...> with forward
 // declared key types. Assume that no pointer key type requires more than 4096
 // bytes of alignment.
 template<typename T>
 struct DenseMapInfo<T*> {
   // The following should hold, but it would require T to be complete:
   // static_assert(alignof(T) <= (1 << Log2MaxAlign),
   //               "DenseMap does not support pointer keys requiring more than "
   //               "Log2MaxAlign bits of alignment");
   static constexpr uintptr_t Log2MaxAlign = 12;

   static inline T* getEmptyKey() {
     uintptr_t Val = static_cast<uintptr_t>(-1);
     Val <<= Log2MaxAlign;
     return reinterpret_cast<T*>(Val);
   }

   static inline T* getTombstoneKey() {
     uintptr_t Val = static_cast<uintptr_t>(-2);
     Val <<= Log2MaxAlign;
     return reinterpret_cast<T*>(Val);
   }

   static unsigned getHashValue(const T *PtrVal) {
     return (unsigned((uintptr_t)PtrVal) >> 4) ^
            (unsigned((uintptr_t)PtrVal) >> 9);
   }

   static bool isEqual(const T *LHS, const T *RHS) { return LHS == RHS; }
 };

 // Provide DenseMapInfo for chars.
 template<> struct DenseMapInfo<char> {
   static inline char getEmptyKey() { return ~0; }
   static inline char getTombstoneKey() { return ~0 - 1; }
   static unsigned getHashValue(const char& Val) { return Val * 37U; }

   static bool isEqual(const char &LHS, const char &RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for unsigned chars.
 template <> struct DenseMapInfo<unsigned char> {
   static inline unsigned char getEmptyKey() { return ~0; }
   static inline unsigned char getTombstoneKey() { return ~0 - 1; }
   static unsigned getHashValue(const unsigned char &Val) { return Val * 37U; }

   static bool isEqual(const unsigned char &LHS, const unsigned char &RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for unsigned shorts.
 template <> struct DenseMapInfo<unsigned short> {
   static inline unsigned short getEmptyKey() { return 0xFFFF; }
   static inline unsigned short getTombstoneKey() { return 0xFFFF - 1; }
   static unsigned getHashValue(const unsigned short &Val) { return Val * 37U; }

   static bool isEqual(const unsigned short &LHS, const unsigned short &RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for unsigned ints.
 template<> struct DenseMapInfo<unsigned> {
   static inline unsigned getEmptyKey() { return ~0U; }
   static inline unsigned getTombstoneKey() { return ~0U - 1; }
   static unsigned getHashValue(const unsigned& Val) { return Val * 37U; }

   static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for unsigned longs.
 template<> struct DenseMapInfo<unsigned long> {
   static inline unsigned long getEmptyKey() { return ~0UL; }
   static inline unsigned long getTombstoneKey() { return ~0UL - 1L; }

   static unsigned getHashValue(const unsigned long& Val) {
     return (unsigned)(Val * 37UL);
   }

   static bool isEqual(const unsigned long& LHS, const unsigned long& RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for unsigned long longs.
 template<> struct DenseMapInfo<unsigned long long> {
   static inline unsigned long long getEmptyKey() { return ~0ULL; }
   static inline unsigned long long getTombstoneKey() { return ~0ULL - 1ULL; }

   static unsigned getHashValue(const unsigned long long& Val) {
     return (unsigned)(Val * 37ULL);
   }

   static bool isEqual(const unsigned long long& LHS,
                       const unsigned long long& RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for shorts.
 template <> struct DenseMapInfo<short> {
   static inline short getEmptyKey() { return 0x7FFF; }
   static inline short getTombstoneKey() { return -0x7FFF - 1; }
   static unsigned getHashValue(const short &Val) { return Val * 37U; }
   static bool isEqual(const short &LHS, const short &RHS) { return LHS == RHS; }
 };

 // Provide DenseMapInfo for ints.
 template<> struct DenseMapInfo<int> {
   static inline int getEmptyKey() { return 0x7fffffff; }
   static inline int getTombstoneKey() { return -0x7fffffff - 1; }
   static unsigned getHashValue(const int& Val) { return (unsigned)(Val * 37U); }

   static bool isEqual(const int& LHS, const int& RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for longs.
 template<> struct DenseMapInfo<long> {
   static inline long getEmptyKey() {
     return (1UL << (sizeof(long) * 8 - 1)) - 1UL;
   }

   static inline long getTombstoneKey() { return getEmptyKey() - 1L; }

   static unsigned getHashValue(const long& Val) {
     return (unsigned)(Val * 37UL);
   }

   static bool isEqual(const long& LHS, const long& RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for long longs.
 template<> struct DenseMapInfo<long long> {
   static inline long long getEmptyKey() { return 0x7fffffffffffffffLL; }
   static inline long long getTombstoneKey() { return -0x7fffffffffffffffLL-1; }

   static unsigned getHashValue(const long long& Val) {
     return (unsigned)(Val * 37ULL);
   }

   static bool isEqual(const long long& LHS,
                       const long long& RHS) {
     return LHS == RHS;
   }
 };

 // Provide DenseMapInfo for all pairs whose members have info.
 template<typename T, typename U>
 struct DenseMapInfo<std::pair<T, U>> {
   using Pair = std::pair<T, U>;
   using FirstInfo = DenseMapInfo<T>;
   using SecondInfo = DenseMapInfo<U>;

   static inline Pair getEmptyKey() {
     return std::make_pair(FirstInfo::getEmptyKey(),
                           SecondInfo::getEmptyKey());
   }

   static inline Pair getTombstoneKey() {
     return std::make_pair(FirstInfo::getTombstoneKey(),
                           SecondInfo::getTombstoneKey());
   }

   static unsigned getHashValue(const Pair& PairVal) {
     return detail::combineHashValue(FirstInfo::getHashValue(PairVal.first),
                                     SecondInfo::getHashValue(PairVal.second));
   }

   static bool isEqual(const Pair &LHS, const Pair &RHS) {
     return FirstInfo::isEqual(LHS.first, RHS.first) &&
            SecondInfo::isEqual(LHS.second, RHS.second);
   }
 };

 // Provide DenseMapInfo for all tuples whose members have info.
 template <typename... Ts> struct DenseMapInfo<std::tuple<Ts...>> {
   using Tuple = std::tuple<Ts...>;

   static inline Tuple getEmptyKey() {
     return Tuple(DenseMapInfo<Ts>::getEmptyKey()...);
   }

   static inline Tuple getTombstoneKey() {
     return Tuple(DenseMapInfo<Ts>::getTombstoneKey()...);
   }

   template <unsigned I>
   static unsigned getHashValueImpl(const Tuple &values, std::false_type) {
     using EltType = std::tuple_element_t<I, Tuple>;
     std::integral_constant<bool, I + 1 == sizeof...(Ts)> atEnd;
     return detail::combineHashValue(
         DenseMapInfo<EltType>::getHashValue(std::get<I>(values)),
         getHashValueImpl<I + 1>(values, atEnd));
   }

   template <unsigned I>
   static unsigned getHashValueImpl(const Tuple &, std::true_type) {
     return 0;
   }

   static unsigned getHashValue(const std::tuple<Ts...> &values) {
     std::integral_constant<bool, 0 == sizeof...(Ts)> atEnd;
     return getHashValueImpl<0>(values, atEnd);
   }

   template <unsigned I>
   static bool isEqualImpl(const Tuple &lhs, const Tuple &rhs, std::false_type) {
     using EltType = std::tuple_element_t<I, Tuple>;
     std::integral_constant<bool, I + 1 == sizeof...(Ts)> atEnd;
     return DenseMapInfo<EltType>::isEqual(std::get<I>(lhs), std::get<I>(rhs)) &&
            isEqualImpl<I + 1>(lhs, rhs, atEnd);
   }

   template <unsigned I>
   static bool isEqualImpl(const Tuple &, const Tuple &, std::true_type) {
     return true;
   }

   static bool isEqual(const Tuple &lhs, const Tuple &rhs) {
     std::integral_constant<bool, 0 == sizeof...(Ts)> atEnd;
     return isEqualImpl<0>(lhs, rhs, atEnd);
   }
 };

 // Provide DenseMapInfo for variants whose all alternatives have DenseMapInfo.
 template <typename... Ts> struct DenseMapInfo<std::variant<Ts...>> {
   using Variant = std::variant<Ts...>;
   using FirstT = std::variant_alternative_t<0, Variant>;

   static inline Variant getEmptyKey() {
     return Variant(std::in_place_index<0>, DenseMapInfo<FirstT>::getEmptyKey());
   }

   static inline Variant getTombstoneKey() {
     return Variant(std::in_place_index<0>,
                    DenseMapInfo<FirstT>::getTombstoneKey());
   }

   static unsigned getHashValue(const Variant &Val) {
     return std::visit(
         [&Val](auto &&Alternative) {
           using T = std::decay_t<decltype(Alternative)>;
           // Include index in hash to make sure same value as different
           // alternatives don't collide.
           return detail::combineHashValue(
               DenseMapInfo<size_t>::getHashValue(Val.index()),
               DenseMapInfo<T>::getHashValue(Alternative));
         },
         Val);
   }

   static bool isEqual(const Variant &LHS, const Variant &RHS) {
     return LHS == RHS;
   }
 };
 } // end namespace llvm

 #endif // LLVM_ADT_DENSEMAPINFO_H
	//===- llvm/ADT/DenseMapInfo.h - Type traits for DenseMap -------- 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
	//
	//===----------------------------------------------------------------------===//
	///
	/// \file
	/// This file defines DenseMapInfo traits for DenseMap.
	///
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_ADT_DENSEMAPINFO_H
	#define LLVM_ADT_DENSEMAPINFO_H

	#include <cassert>
	#include <cstddef>
	#include <cstdint>
	#include <tuple>
	#include <type_traits>
	#include <utility>
	#include <variant>

	namespace llvm {

	namespace detail {

	/// Simplistic combination of 32-bit hash values into 32-bit hash values.
	static inline unsigned combineHashValue(unsigned a, unsigned b) {
	uint64_t key = (uint64_t)a << 32 \| (uint64_t)b;
	key += ~(key << 32);
	key ^= (key >> 22);
	key += ~(key << 13);
	key ^= (key >> 8);
	key += (key << 3);
	key ^= (key >> 15);
	key += ~(key << 27);
	key ^= (key >> 31);
	return (unsigned)key;
	}

	} // end namespace detail

	/// An information struct used to provide DenseMap with the various necessary
	/// components for a given value type `T`. `Enable` is an optional additional
	/// parameter that is used to support SFINAE (generally using std::enable_if_t)
	/// in derived DenseMapInfo specializations; in non-SFINAE use cases this should
	/// just be `void`.
	template<typename T, typename Enable = void>
	struct DenseMapInfo {
	//static inline T getEmptyKey();
	//static inline T getTombstoneKey();
	//static unsigned getHashValue(const T &Val);
	//static bool isEqual(const T &LHS, const T &RHS);
	};

	// Provide DenseMapInfo for all pointers. Come up with sentinel pointer values
	// that are aligned to alignof(T) bytes, but try to avoid requiring T to be
	// complete. This allows clients to instantiate DenseMap<T*, ...> with forward
	// declared key types. Assume that no pointer key type requires more than 4096
	// bytes of alignment.
	template<typename T>
	struct DenseMapInfo<T*> {
	// The following should hold, but it would require T to be complete:
	// static_assert(alignof(T) <= (1 << Log2MaxAlign),
	// "DenseMap does not support pointer keys requiring more than "
	// "Log2MaxAlign bits of alignment");
	static constexpr uintptr_t Log2MaxAlign = 12;

	static inline T* getEmptyKey() {
	uintptr_t Val = static_cast<uintptr_t>(-1);
	Val <<= Log2MaxAlign;
	return reinterpret_cast<T*>(Val);
	}

	static inline T* getTombstoneKey() {
	uintptr_t Val = static_cast<uintptr_t>(-2);
	Val <<= Log2MaxAlign;
	return reinterpret_cast<T*>(Val);
	}

	static unsigned getHashValue(const T *PtrVal) {
	return (unsigned((uintptr_t)PtrVal) >> 4) ^
	(unsigned((uintptr_t)PtrVal) >> 9);
	}

	static bool isEqual(const T LHS, const T RHS) { return LHS == RHS; }
	};

	// Provide DenseMapInfo for chars.
	template<> struct DenseMapInfo<char> {
	static inline char getEmptyKey() { return ~0; }
	static inline char getTombstoneKey() { return ~0 - 1; }
	static unsigned getHashValue(const char& Val) { return Val * 37U; }

	static bool isEqual(const char &LHS, const char &RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for unsigned chars.
	template <> struct DenseMapInfo<unsigned char> {
	static inline unsigned char getEmptyKey() { return ~0; }
	static inline unsigned char getTombstoneKey() { return ~0 - 1; }
	static unsigned getHashValue(const unsigned char &Val) { return Val * 37U; }

	static bool isEqual(const unsigned char &LHS, const unsigned char &RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for unsigned shorts.
	template <> struct DenseMapInfo<unsigned short> {
	static inline unsigned short getEmptyKey() { return 0xFFFF; }
	static inline unsigned short getTombstoneKey() { return 0xFFFF - 1; }
	static unsigned getHashValue(const unsigned short &Val) { return Val * 37U; }

	static bool isEqual(const unsigned short &LHS, const unsigned short &RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for unsigned ints.
	template<> struct DenseMapInfo<unsigned> {
	static inline unsigned getEmptyKey() { return ~0U; }
	static inline unsigned getTombstoneKey() { return ~0U - 1; }
	static unsigned getHashValue(const unsigned& Val) { return Val * 37U; }

	static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for unsigned longs.
	template<> struct DenseMapInfo<unsigned long> {
	static inline unsigned long getEmptyKey() { return ~0UL; }
	static inline unsigned long getTombstoneKey() { return ~0UL - 1L; }

	static unsigned getHashValue(const unsigned long& Val) {
	return (unsigned)(Val * 37UL);
	}

	static bool isEqual(const unsigned long& LHS, const unsigned long& RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for unsigned long longs.
	template<> struct DenseMapInfo<unsigned long long> {
	static inline unsigned long long getEmptyKey() { return ~0ULL; }
	static inline unsigned long long getTombstoneKey() { return ~0ULL - 1ULL; }

	static unsigned getHashValue(const unsigned long long& Val) {
	return (unsigned)(Val * 37ULL);
	}

	static bool isEqual(const unsigned long long& LHS,
	const unsigned long long& RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for shorts.
	template <> struct DenseMapInfo<short> {
	static inline short getEmptyKey() { return 0x7FFF; }
	static inline short getTombstoneKey() { return -0x7FFF - 1; }
	static unsigned getHashValue(const short &Val) { return Val * 37U; }
	static bool isEqual(const short &LHS, const short &RHS) { return LHS == RHS; }
	};

	// Provide DenseMapInfo for ints.
	template<> struct DenseMapInfo<int> {
	static inline int getEmptyKey() { return 0x7fffffff; }
	static inline int getTombstoneKey() { return -0x7fffffff - 1; }
	static unsigned getHashValue(const int& Val) { return (unsigned)(Val * 37U); }

	static bool isEqual(const int& LHS, const int& RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for longs.
	template<> struct DenseMapInfo<long> {
	static inline long getEmptyKey() {
	return (1UL << (sizeof(long) * 8 - 1)) - 1UL;
	}

	static inline long getTombstoneKey() { return getEmptyKey() - 1L; }

	static unsigned getHashValue(const long& Val) {
	return (unsigned)(Val * 37UL);
	}

	static bool isEqual(const long& LHS, const long& RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for long longs.
	template<> struct DenseMapInfo<long long> {
	static inline long long getEmptyKey() { return 0x7fffffffffffffffLL; }
	static inline long long getTombstoneKey() { return -0x7fffffffffffffffLL-1; }

	static unsigned getHashValue(const long long& Val) {
	return (unsigned)(Val * 37ULL);
	}

	static bool isEqual(const long long& LHS,
	const long long& RHS) {
	return LHS == RHS;
	}
	};

	// Provide DenseMapInfo for all pairs whose members have info.
	template<typename T, typename U>
	struct DenseMapInfo<std::pair<T, U>> {
	using Pair = std::pair<T, U>;
	using FirstInfo = DenseMapInfo<T>;
	using SecondInfo = DenseMapInfo<U>;

	static inline Pair getEmptyKey() {
	return std::make_pair(FirstInfo::getEmptyKey(),
	SecondInfo::getEmptyKey());
	}

	static inline Pair getTombstoneKey() {
	return std::make_pair(FirstInfo::getTombstoneKey(),
	SecondInfo::getTombstoneKey());
	}

	static unsigned getHashValue(const Pair& PairVal) {
	return detail::combineHashValue(FirstInfo::getHashValue(PairVal.first),
	SecondInfo::getHashValue(PairVal.second));
	}

	static bool isEqual(const Pair &LHS, const Pair &RHS) {
	return FirstInfo::isEqual(LHS.first, RHS.first) &&
	SecondInfo::isEqual(LHS.second, RHS.second);
	}
	};

	// Provide DenseMapInfo for all tuples whose members have info.
	template <typename... Ts> struct DenseMapInfo<std::tuple<Ts...>> {
	using Tuple = std::tuple<Ts...>;

	static inline Tuple getEmptyKey() {
	return Tuple(DenseMapInfo<Ts>::getEmptyKey()...);
	}

	static inline Tuple getTombstoneKey() {
	return Tuple(DenseMapInfo<Ts>::getTombstoneKey()...);
	}

	template <unsigned I>
	static unsigned getHashValueImpl(const Tuple &values, std::false_type) {
	using EltType = std::tuple_element_t<I, Tuple>;
	std::integral_constant<bool, I + 1 == sizeof...(Ts)> atEnd;
	return detail::combineHashValue(
	DenseMapInfo<EltType>::getHashValue(std::get<I>(values)),
	getHashValueImpl<I + 1>(values, atEnd));
	}

	template <unsigned I>
	static unsigned getHashValueImpl(const Tuple &, std::true_type) {
	return 0;
	}

	static unsigned getHashValue(const std::tuple<Ts...> &values) {
	std::integral_constant<bool, 0 == sizeof...(Ts)> atEnd;
	return getHashValueImpl<0>(values, atEnd);
	}

	template <unsigned I>
	static bool isEqualImpl(const Tuple &lhs, const Tuple &rhs, std::false_type) {
	using EltType = std::tuple_element_t<I, Tuple>;
	std::integral_constant<bool, I + 1 == sizeof...(Ts)> atEnd;
	return DenseMapInfo<EltType>::isEqual(std::get<I>(lhs), std::get<I>(rhs)) &&
	isEqualImpl<I + 1>(lhs, rhs, atEnd);
	}

	template <unsigned I>
	static bool isEqualImpl(const Tuple &, const Tuple &, std::true_type) {
	return true;
	}

	static bool isEqual(const Tuple &lhs, const Tuple &rhs) {
	std::integral_constant<bool, 0 == sizeof...(Ts)> atEnd;
	return isEqualImpl<0>(lhs, rhs, atEnd);
	}
	};

	// Provide DenseMapInfo for variants whose all alternatives have DenseMapInfo.
	template <typename... Ts> struct DenseMapInfo<std::variant<Ts...>> {
	using Variant = std::variant<Ts...>;
	using FirstT = std::variant_alternative_t<0, Variant>;

	static inline Variant getEmptyKey() {
	return Variant(std::in_place_index<0>, DenseMapInfo<FirstT>::getEmptyKey());
	}

	static inline Variant getTombstoneKey() {
	return Variant(std::in_place_index<0>,
	DenseMapInfo<FirstT>::getTombstoneKey());
	}

	static unsigned getHashValue(const Variant &Val) {
	return std::visit(
	[&Val](auto &&Alternative) {
	using T = std::decay_t<decltype(Alternative)>;
	// Include index in hash to make sure same value as different
	// alternatives don't collide.
	return detail::combineHashValue(
	DenseMapInfo<size_t>::getHashValue(Val.index()),
	DenseMapInfo<T>::getHashValue(Alternative));
	},
	Val);
	}

	static bool isEqual(const Variant &LHS, const Variant &RHS) {
	return LHS == RHS;
	}
	};
	} // end namespace llvm

	#endif // LLVM_ADT_DENSEMAPINFO_H