diff options
| -rw-r--r-- | include/llvm/ADT/Hashing.h | 835 | ||||
| -rw-r--r-- | include/llvm/Support/system_error.h | 11 | ||||
| -rw-r--r-- | include/llvm/Support/type_traits.h | 60 | ||||
| -rw-r--r-- | lib/Support/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | lib/VMCore/LLVMContextImpl.h | 16 | ||||
| -rw-r--r-- | unittests/ADT/HashingTest.cpp | 311 |
6 files changed, 1052 insertions, 182 deletions
diff --git a/include/llvm/ADT/Hashing.h b/include/llvm/ADT/Hashing.h index 682dc22..ccf352c 100644 --- a/include/llvm/ADT/Hashing.h +++ b/include/llvm/ADT/Hashing.h @@ -7,170 +7,745 @@ // //===----------------------------------------------------------------------===// // -// This file defines utilities for computing hash values for various data types. +// This file implements the newly proposed standard C++ interfaces for hashing +// arbitrary data and building hash functions for user-defined types. This +// interface was originally proposed in N3333[1] and is currently under review +// for inclusion in a future TR and/or standard. +// +// The primary interfaces provide are comprised of one type and three functions: +// +// -- 'hash_code' class is an opaque type representing the hash code for some +// data. It is the intended product of hashing, and can be used to implement +// hash tables, checksumming, and other common uses of hashes. It is not an +// integer type (although it can be converted to one) because it is risky +// to assume much about the internals of a hash_code. In particular, each +// execution of the program has a high probability of producing a different +// hash_code for a given input. Thus their values are not stable to save or +// persist, and should only be used during the execution for the +// construction of hashing datastructures. +// +// -- 'hash_value' is a function designed to be overloaded for each +// user-defined type which wishes to be used within a hashing context. It +// should be overloaded within the user-defined type's namespace and found +// via ADL. Overloads for primitive types are provided by this library. +// +// -- 'hash_combine' and 'hash_combine_range' are functions designed to aid +// programmers in easily and intuitively combining a set of data into +// a single hash_code for their object. They should only logically be used +// within the implementation of a 'hash_value' routine or similar context. +// +// Note that 'hash_combine_range' contains very special logic for hashing +// a contiguous array of integers or pointers. This logic is *extremely* fast, +// on a modern Intel "Gainestown" Xeon (Nehalem uarch) @2.2 GHz, these were +// benchmarked at over 6.5 GiB/s for large keys, and <20 cycles/hash for keys +// under 32-bytes. // //===----------------------------------------------------------------------===// #ifndef LLVM_ADT_HASHING_H #define LLVM_ADT_HASHING_H -#include "llvm/ADT/ArrayRef.h" -#include "llvm/ADT/StringRef.h" -#include "llvm/Support/AlignOf.h" -#include "llvm/Support/Compiler.h" +#include "llvm/ADT/STLExtras.h" #include "llvm/Support/DataTypes.h" +#include "llvm/Support/type_traits.h" +#include <algorithm> +#include <cassert> #include <cstring> +#include <iterator> +#include <utility> + +// Allow detecting C++11 feature availability when building with Clang without +// breaking other compilers. +#ifndef __has_feature +# define __has_feature(x) 0 +#endif namespace llvm { -/// Class to compute a hash value from multiple data fields of arbitrary -/// types. Note that if you are hashing a single data type, such as a -/// string, it may be cheaper to use a hash algorithm that is tailored -/// for that specific data type. -/// Typical Usage: -/// GeneralHash Hash; -/// Hash.add(someValue); -/// Hash.add(someOtherValue); -/// return Hash.finish(); -/// Adapted from MurmurHash2 by Austin Appleby -class GeneralHash { -private: - enum { - M = 0x5bd1e995 - }; - unsigned Hash; - unsigned Count; +/// \brief An opaque object representing a hash code. +/// +/// This object represents the result of hashing some entity. It is intended to +/// be used to implement hashtables or other hashing-based data structures. +/// While it wraps and exposes a numeric value, this value should not be +/// trusted to be stable or predictable across processes or executions. +/// +/// In order to obtain the hash_code for an object 'x': +/// \code +/// using llvm::hash_value; +/// llvm::hash_code code = hash_value(x); +/// \endcode +/// +/// Also note that there are two numerical values which are reserved, and the +/// implementation ensures will never be produced for real hash_codes. These +/// can be used as sentinels within hashing data structures. +class hash_code { + size_t value; + public: - GeneralHash(unsigned Seed = 0) : Hash(Seed), Count(0) {} + /// \brief Default construct a hash_code. Constructs a null code. + hash_code() : value() {} - /// Add a pointer value. - /// Note: this adds pointers to the hash using sizes and endianness that - /// depend on the host. It doesn't matter however, because hashing on - /// pointer values is inherently unstable. - template<typename T> - GeneralHash& add(const T *PtrVal) { - addBits(&PtrVal, &PtrVal + 1); - return *this; + /// \brief Form a hash code directly from a numerical value. + hash_code(size_t value) : value(value) { + // Ensure we don't form a hash_code with one of the prohibited values. + assert(value != get_null_code().value); + assert(value != get_invalid_code().value); } - /// Add an ArrayRef of arbitrary data. - template<typename T> - GeneralHash& add(ArrayRef<T> ArrayVal) { - addBits(ArrayVal.begin(), ArrayVal.end()); - return *this; + /// \brief Convert the hash code to its numerical value for use. + /*explicit*/ operator size_t() const { return value; } + + /// \brief Get a hash_code object which corresponds to a null code. + /// + /// The null code must never be the result of any 'hash_value' calls and can + /// be used to detect an unset hash_code. + static hash_code get_null_code() { return hash_code(); } + + /// \brief Get a hash_code object which corresponds to an invalid code. + /// + /// The invalid code must never be the result of any 'hash_value' calls. This + /// can be used to flag invalid hash_codes or mark entries in a hash table. + static hash_code get_invalid_code() { + hash_code invalid_code; + invalid_code.value = static_cast<size_t>(-1); + return invalid_code; } - /// Add a string - GeneralHash& add(StringRef StrVal) { - addBits(StrVal.begin(), StrVal.end()); - return *this; + friend bool operator==(const hash_code &lhs, const hash_code &rhs) { + return lhs.value == rhs.value; + } + friend bool operator!=(const hash_code &lhs, const hash_code &rhs) { + return lhs.value != rhs.value; } - /// Add an signed 32-bit integer. - GeneralHash& add(int32_t Data) { - addInt(uint32_t(Data)); - return *this; + /// \brief Allow a hash_code to be directly run through hash_value. + friend size_t hash_value(const hash_code &code) { return code.value; } +}; + + +// All of the implementation details of actually computing the various hash +// code values are held within this namespace. These routines are included in +// the header file mainly to allow inlining and constant propagation. +namespace hashing { +namespace detail { + +inline uint64_t fetch64(const char *p) { + uint64_t result; + memcpy(&result, p, sizeof(result)); + return result; +} + +inline uint32_t fetch32(const char *p) { + uint32_t result; + memcpy(&result, p, sizeof(result)); + return result; +} + +/// Some primes between 2^63 and 2^64 for various uses. +static const uint64_t k0 = 0xc3a5c85c97cb3127ULL; +static const uint64_t k1 = 0xb492b66fbe98f273ULL; +static const uint64_t k2 = 0x9ae16a3b2f90404fULL; +static const uint64_t k3 = 0xc949d7c7509e6557ULL; + +/// \brief Bitwise right rotate. +/// Normally this will compile to a single instruction, especially if the +/// shift is a manifest constant. +inline uint64_t rotate(uint64_t val, unsigned shift) { + // Avoid shifting by 64: doing so yields an undefined result. + return shift == 0 ? val : ((val >> shift) | (val << (64 - shift))); +} + +inline uint64_t shift_mix(uint64_t val) { + return val ^ (val >> 47); +} + +inline uint64_t hash_16_bytes(uint64_t low, uint64_t high) { + // Murmur-inspired hashing. + const uint64_t kMul = 0x9ddfea08eb382d69ULL; + uint64_t a = (low ^ high) * kMul; + a ^= (a >> 47); + uint64_t b = (high ^ a) * kMul; + b ^= (b >> 47); + b *= kMul; + return b; +} + +inline uint64_t hash_1to3_bytes(const char *s, size_t len, uint64_t seed) { + uint8_t a = s[0]; + uint8_t b = s[len >> 1]; + uint8_t c = s[len - 1]; + uint32_t y = static_cast<uint32_t>(a) + (static_cast<uint32_t>(b) << 8); + uint32_t z = len + (static_cast<uint32_t>(c) << 2); + return shift_mix(y * k2 ^ z * k3 ^ seed) * k2; +} + +inline uint64_t hash_4to8_bytes(const char *s, size_t len, uint64_t seed) { + uint64_t a = fetch32(s); + return hash_16_bytes(len + (a << 3), seed ^ fetch32(s + len - 4)); +} + +inline uint64_t hash_9to16_bytes(const char *s, size_t len, uint64_t seed) { + uint64_t a = fetch64(s); + uint64_t b = fetch64(s + len - 8); + return hash_16_bytes(seed ^ a, rotate(b + len, len)) ^ b; +} + +inline uint64_t hash_17to32_bytes(const char *s, size_t len, uint64_t seed) { + uint64_t a = fetch64(s) * k1; + uint64_t b = fetch64(s + 8); + uint64_t c = fetch64(s + len - 8) * k2; + uint64_t d = fetch64(s + len - 16) * k0; + return hash_16_bytes(rotate(a - b, 43) + rotate(c ^ seed, 30) + d, + a + rotate(b ^ k3, 20) - c + len + seed); +} + +inline uint64_t hash_33to64_bytes(const char *s, size_t len, uint64_t seed) { + uint64_t z = fetch64(s + 24); + uint64_t a = fetch64(s) + (len + fetch64(s + len - 16)) * k0; + uint64_t b = rotate(a + z, 52); + uint64_t c = rotate(a, 37); + a += fetch64(s + 8); + c += rotate(a, 7); + a += fetch64(s + 16); + uint64_t vf = a + z; + uint64_t vs = b + rotate(a, 31) + c; + a = fetch64(s + 16) + fetch64(s + len - 32); + z = fetch64(s + len - 8); + b = rotate(a + z, 52); + c = rotate(a, 37); + a += fetch64(s + len - 24); + c += rotate(a, 7); + a += fetch64(s + len - 16); + uint64_t wf = a + z; + uint64_t ws = b + rotate(a, 31) + c; + uint64_t r = shift_mix((vf + ws) * k2 + (wf + vs) * k0); + return shift_mix(seed ^ (r * k0) + vs) * k2; +} + +inline uint64_t hash_short(const char *s, size_t length, uint64_t seed) { + uint64_t hash; + if (length >= 4 && length <= 8) + hash = hash_4to8_bytes(s, length, seed); + else if (length > 8 && length <= 16) + hash = hash_9to16_bytes(s, length, seed); + else if (length > 16 && length <= 32) + hash = hash_17to32_bytes(s, length, seed); + else if (length > 32) + hash = hash_33to64_bytes(s, length, seed); + else if (length != 0) + hash = hash_1to3_bytes(s, length, seed); + else + return k2 ^ seed; + + // FIXME: The invalid hash_code check is really expensive; there should be + // a better way of ensuring these invariants hold. + if (hash == static_cast<uint64_t>(hash_code::get_null_code())) + hash = k1 ^ seed; + else if (hash == static_cast<uint64_t>(hash_code::get_invalid_code())) + hash = k3 ^ seed; + return hash; +} + +/// \brief The intermediate state used during hashing. +/// Currently, the algorithm for computing hash codes is based on CityHash and +/// keeps 56 bytes of arbitrary state. +struct hash_state { + uint64_t h0, h1, h2, h3, h4, h5, h6; + uint64_t seed; + + /// \brief Create a new hash_state structure and initialize it based on the + /// seed and the first 64-byte chunk. + /// This effectively performs the initial mix. + static hash_state create(const char *s, uint64_t seed) { + hash_state state = { + 0, seed, hash_16_bytes(seed, k1), rotate(seed ^ k1, 49), + seed * k1, shift_mix(seed), hash_16_bytes(state.h4, state.h5), + seed + }; + state.mix(s); + return state; } - /// Add an unsigned 32-bit integer. - GeneralHash& add(uint32_t Data) { - addInt(Data); - return *this; + /// \brief Mix 32-bytes from the input sequence into the 16-bytes of 'a' + /// and 'b', including whatever is already in 'a' and 'b'. + static void mix_32_bytes(const char *s, uint64_t &a, uint64_t &b) { + a += fetch64(s); + uint64_t c = fetch64(s + 24); + b = rotate(b + a + c, 21); + uint64_t d = a; + a += fetch64(s + 8) + fetch64(s + 16); + b += rotate(a, 44) + d; + a += c; } - /// Add an signed 64-bit integer. - GeneralHash& add(int64_t Data) { - addInt(uint64_t(Data)); - return *this; + /// \brief Mix in a 64-byte buffer of data. + /// We mix all 64 bytes even when the chunk length is smaller, but we + /// record the actual length. + void mix(const char *s) { + h0 = rotate(h0 + h1 + h3 + fetch64(s + 8), 37) * k1; + h1 = rotate(h1 + h4 + fetch64(s + 48), 42) * k1; + h0 ^= h6; + h1 += h3 + fetch64(s + 40); + h2 = rotate(h2 + h5, 33) * k1; + h3 = h4 * k1; + h4 = h0 + h5; + mix_32_bytes(s, h3, h4); + h5 = h2 + h6; + h6 = h1 + fetch64(s + 16); + mix_32_bytes(s + 32, h5, h6); + std::swap(h2, h0); } - /// Add an unsigned 64-bit integer. - GeneralHash& add(uint64_t Data) { - addInt(Data); - return *this; + /// \brief Compute the final 64-bit hash code value based on the current + /// state and the length of bytes hashed. + uint64_t finalize(size_t length) { + uint64_t final_value + = hash_16_bytes(hash_16_bytes(h3, h5) + shift_mix(h1) * k1 + h2, + hash_16_bytes(h4, h6) + shift_mix(length) * k1 + h0); + if (final_value == static_cast<uint64_t>(hash_code::get_null_code())) + final_value = k1 ^ seed; + if (final_value == static_cast<uint64_t>(hash_code::get_invalid_code())) + final_value = k3 ^ seed; + return final_value; } +}; - /// Add a float - GeneralHash& add(float Data) { - union { - float D; uint32_t I; - }; - D = Data; - addInt(I); - return *this; + +/// \brief A global, fixed seed-override variable. +/// +/// This variable can be set using the \see llvm::set_fixed_execution_seed +/// function. See that function for details. Do not, under any circumstances, +/// set or read this variable. +extern size_t fixed_seed_override; + +inline size_t get_execution_seed() { + // FIXME: This needs to be a per-execution seed. This is just a placeholder + // implementation. Switching to a per-execution seed is likely to flush out + // instability bugs and so will happen as its own commit. + // + // However, if there is a fixed seed override set the first time this is + // called, return that instead of the per-execution seed. + static size_t seed = fixed_seed_override ? fixed_seed_override + : 0xff51afd7ed558ccdULL; + return seed; +} + + +/// \brief Helper to hash the value of a single integer. +/// +/// Overloads for smaller integer types are not provided to ensure consistent +/// behavior in the presence of integral promotions. Essentially, +/// "hash_value('4')" and "hash_value('0' + 4)" should be the same. +inline hash_code hash_integer_value(uint64_t value) { + // Similar to hash_4to8_bytes but using a seed instead of length. + const uint64_t seed = get_execution_seed(); + const char *s = reinterpret_cast<const char *>(&value); + const uint64_t a = fetch32(s); + return hash_16_bytes(seed + (a << 3), fetch32(s + 4)); +} + +} // namespace detail +} // namespace hashing + + +/// \brief Override the execution seed with a fixed value. +/// +/// This hashing library uses a per-execution seed designed to change on each +/// run with high probability in order to ensure that the hash codes are not +/// attackable and to ensure that output which is intended to be stable does +/// not rely on the particulars of the hash codes produced. +/// +/// That said, there are use cases where it is important to be able to +/// reproduce *exactly* a specific behavior. To that end, we provide a function +/// which will forcibly set the seed to a fixed value. This must be done at the +/// start of the program, before any hashes are computed. Also, it cannot be +/// undone. This makes it thread-hostile and very hard to use outside of +/// immediately on start of a simple program designed for reproducible +/// behavior. +void set_fixed_execution_hash_seed(size_t fixed_value); + + +/// \brief Compute a hash_code for any integer value. +/// +/// Note that this function is intended to compute the same hash_code for +/// a particular value without regard to the pre-promotion type. This is in +/// contrast to hash_combine which may produce different hash_codes for +/// differing argument types even if they would implicit promote to a common +/// type without changing the value. +template <typename T> +typename enable_if<is_integral<T>, hash_code>::type hash_value(T value) { + return ::llvm::hashing::detail::hash_integer_value(value); +} + +/// \brief Compute a hash_code for a pointer's address. +/// +/// N.B.: This hashes the *address*. Not the value and not the type. +template <typename T> hash_code hash_value(const T *ptr) { + return ::llvm::hashing::detail::hash_integer_value( + reinterpret_cast<uintptr_t>(ptr)); +} + + +// Implementation details for implementing hash combining functions. +namespace hashing { +namespace detail { + +/// \brief Trait to indicate whether a type's bits can be hashed directly. +/// +/// A type trait which is true if we want to combine values for hashing by +/// reading the underlying data. It is false if values of this type must +/// first be passed to hash_value, and the resulting hash_codes combined. +// +// FIXME: We want to replace is_integral and is_pointer here with a predicate +// which asserts that comparing the underlying storage of two values of the +// type for equality is equivalent to comparing the two values for equality. +// For all the platforms we care about, this holds for integers and pointers, +// but there are platforms where it doesn't and we would like to support +// user-defined types which happen to satisfy this property. +template <typename T> struct is_hashable_data + : integral_constant<bool, ((is_integral<T>::value || is_pointer<T>::value) && + 64 % sizeof(T) == 0)> {}; + +/// \brief Helper to get the hashable data representation for a type. +/// This variant is enabled when the type itself can be used. +template <typename T> +typename enable_if<is_hashable_data<T>, T>::type +get_hashable_data(const T &value) { + return value; +} +/// \brief Helper to get the hashable data representation for a type. +/// This variant is enabled when we must first call hash_value and use the +/// result as our data. +template <typename T> +typename enable_if_c<!is_hashable_data<T>::value, size_t>::type +get_hashable_data(const T &value) { + using ::llvm::hash_value; + return hash_value(value); +} + +/// \brief Helper to store data from a value into a buffer and advance the +/// pointer into that buffer. +/// +/// This routine first checks whether there is enough space in the provided +/// buffer, and if not immediately returns false. If there is space, it +/// copies the underlying bytes of value into the buffer, advances the +/// buffer_ptr past the copied bytes, and returns true. +template <typename T> +bool store_and_advance(char *&buffer_ptr, char *buffer_end, const T& value, + size_t offset = 0) { + size_t store_size = sizeof(value) - offset; + if (buffer_ptr + store_size > buffer_end) + return false; + const char *value_data = reinterpret_cast<const char *>(&value); + memcpy(buffer_ptr, value_data + offset, store_size); + buffer_ptr += store_size; + return true; +} + +/// \brief Implement the combining of integral values into a hash_code. +/// +/// This overload is selected when the value type of the iterator is +/// integral. Rather than computing a hash_code for each object and then +/// combining them, this (as an optimization) directly combines the integers. +template <typename InputIteratorT> +hash_code hash_combine_range_impl(InputIteratorT first, InputIteratorT last) { + typedef typename std::iterator_traits<InputIteratorT>::value_type ValueT; + const size_t seed = get_execution_seed(); + char buffer[64], *buffer_ptr = buffer; + char *const buffer_end = buffer_ptr + array_lengthof(buffer); + while (first != last && store_and_advance(buffer_ptr, buffer_end, + get_hashable_data(*first))) + ++first; +/// \brief Metafunction that determines whether the given type is an integral +/// type. + if (first == last) + return hash_short(buffer, buffer_ptr - buffer, seed); + assert(buffer_ptr == buffer_end); + + hash_state state = state.create(buffer, seed); + size_t length = 64; + while (first != last) { + // Fill up the buffer. We don't clear it, which re-mixes the last round + // when only a partial 64-byte chunk is left. + buffer_ptr = buffer; + while (first != last && store_and_advance(buffer_ptr, buffer_end, + get_hashable_data(*first))) + ++first; + + // Rotate the buffer if we did a partial fill in order to simulate doing + // a mix of the last 64-bytes. That is how the algorithm works when we + // have a contiguous byte sequence, and we want to emulate that here. + std::rotate(buffer, buffer_ptr, buffer_end); + + // Mix this chunk into the current state. + state.mix(buffer); + length += buffer_ptr - buffer; + }; + + return state.finalize(length); +} + +/// \brief Implement the combining of integral values into a hash_code. +/// +/// This overload is selected when the value type of the iterator is integral +/// and when the input iterator is actually a pointer. Rather than computing +/// a hash_code for each object and then combining them, this (as an +/// optimization) directly combines the integers. Also, because the integers +/// are stored in contiguous memory, this routine avoids copying each value +/// and directly reads from the underlying memory. +template <typename ValueT> +typename enable_if<is_hashable_data<ValueT>, hash_code>::type +hash_combine_range_impl(const ValueT *first, const ValueT *last) { + const size_t seed = get_execution_seed(); + const char *s_begin = reinterpret_cast<const char *>(first); + const char *s_end = reinterpret_cast<const char *>(last); + const size_t length = std::distance(s_begin, s_end); + if (length <= 64) + return hash_short(s_begin, length, seed); + + const char *s_aligned_end = s_begin + (length & ~63); + hash_state state = state.create(s_begin, seed); + s_begin += 64; + while (s_begin != s_aligned_end) { + state.mix(s_begin); + s_begin += 64; } + if (length & 63) + state.mix(s_end - 64); - /// Add a double - GeneralHash& add(double Data) { - union { - double D; uint64_t I; - }; - D = Data; - addInt(I); - return *this; - } - - // Do a few final mixes of the hash to ensure the last few - // bytes are well-incorporated. - unsigned finish() { - mix(Count); - Hash ^= Hash >> 13; - Hash *= M; - Hash ^= Hash >> 15; - return Hash; - } - -private: - void mix(uint32_t Data) { - ++Count; - Data *= M; - Data ^= Data >> 24; - Data *= M; - Hash *= M; - Hash ^= Data; - } - - // Add a single uint32 value - void addInt(uint32_t Val) { - mix(Val); - } - - // Add a uint64 value - void addInt(uint64_t Val) { - mix(uint32_t(Val >> 32)); - mix(uint32_t(Val)); - } - - // Add a range of bytes from I to E. - template<bool ElementsHaveEvenLength> - void addBytes(const char *I, const char *E) { - uint32_t Data; - // Note that aliasing rules forbid us from dereferencing - // reinterpret_cast<uint32_t *>(I) even if I happens to be suitably - // aligned, so we use memcpy instead. - for (; E - I >= ptrdiff_t(sizeof Data); I += sizeof Data) { - // A clever compiler should be able to turn this memcpy into a single - // aligned or unaligned load (depending on the alignment of the type T - // that was used in the call to addBits). - std::memcpy(&Data, I, sizeof Data); - mix(Data); - } - if (!ElementsHaveEvenLength && I != E) { - Data = 0; - std::memcpy(&Data, I, E - I); - mix(Data); + return state.finalize(length); +} + +} // namespace detail +} // namespace hashing + + +/// \brief Compute a hash_code for a sequence of values. +/// +/// This hashes a sequence of values. It produces the same hash_code as +/// 'hash_combine(a, b, c, ...)', but can run over arbitrary sized sequences +/// and is significantly faster given pointers and types which can be hashed as +/// a sequence of bytes. +template <typename InputIteratorT> +hash_code hash_combine_range(InputIteratorT first, InputIteratorT last) { + return ::llvm::hashing::detail::hash_combine_range_impl(first, last); +} + + +// Implementation details for hash_combine. +namespace hashing { +namespace detail { + +/// \brief Helper class to manage the recursive combining of hash_combine +/// arguments. +/// +/// This class exists to manage the state and various calls involved in the +/// recursive combining of arguments used in hash_combine. It is particularly +/// useful at minimizing the code in the recursive calls to ease the pain +/// caused by a lack of variadic functions. +class hash_combine_recursive_helper { + const size_t seed; + char buffer[64]; + char *const buffer_end; + char *buffer_ptr; + size_t length; + hash_state state; + +public: + /// \brief Construct a recursive hash combining helper. + /// + /// This sets up the state for a recursive hash combine, including getting + /// the seed and buffer setup. + hash_combine_recursive_helper() + : seed(get_execution_seed()), + buffer_end(buffer + array_lengthof(buffer)), + buffer_ptr(buffer), + length(0) {} + + /// \brief Combine one chunk of data into the current in-flight hash. + /// + /// This merges one chunk of data into the hash. First it tries to buffer + /// the data. If the buffer is full, it hashes the buffer into its + /// hash_state, empties it, and then merges the new chunk in. This also + /// handles cases where the data straddles the end of the buffer. + template <typename T> void combine_data(T data) { + if (!store_and_advance(buffer_ptr, buffer_end, data)) { + // Check for skew which prevents the buffer from being packed, and do + // a partial store into the buffer to fill it. This is only a concern + // with the variadic combine because that formation can have varying + // argument types. + size_t partial_store_size = buffer_end - buffer_ptr; + memcpy(buffer_ptr, &data, partial_store_size); + + // If the store fails, our buffer is full and ready to hash. We have to + // either initialize the hash state (on the first full buffer) or mix + // this buffer into the existing hash state. Length tracks the *hashed* + // length, not the buffered length. + if (length == 0) { + state = state.create(buffer, seed); + length = 64; + } else { + // Mix this chunk into the current state and bump length up by 64. + state.mix(buffer); + length += 64; + } + // Reset the buffer_ptr to the head of the buffer for the next chunk of + // data. + buffer_ptr = buffer; + + // Try again to store into the buffer -- this cannot fail as we only + // store types smaller than the buffer. + if (!store_and_advance(buffer_ptr, buffer_end, data, + partial_store_size)) + abort(); } } - // Add a range of bits from I to E. - template<typename T> - void addBits(const T *I, const T *E) { - addBytes<sizeof (T) % sizeof (uint32_t) == 0>( - reinterpret_cast<const char *>(I), - reinterpret_cast<const char *>(E)); +#if defined(__has_feature) && __has_feature(__cxx_variadic_templates__) + + /// \brief Recursive, variadic combining method. + /// + /// This function recurses through each argument, combining that argument + /// into a single hash. + template <typename T, typename ...Ts> + hash_code combine(const T &arg, const Ts &...args) { + combine_data( get_hashable_data(arg)); + + // Recurse to the next argument. + return combine(args...); + } + +#else + // Manually expanded recursive combining methods. See variadic above for + // documentation. + + template <typename T1, typename T2, typename T3, typename T4, typename T5, + typename T6> + hash_code combine(const T1 &arg1, const T2 &arg2, const T3 &arg3, + const T4 &arg4, const T5 &arg5, const T6 &arg6) { + combine_data(get_hashable_data(arg1)); + return combine(arg2, arg3, arg4, arg5, arg6); + } + template <typename T1, typename T2, typename T3, typename T4, typename T5> + hash_code combine(const T1 &arg1, const T2 &arg2, const T3 &arg3, + const T4 &arg4, const T5 &arg5) { + combine_data(get_hashable_data(arg1)); + return combine(arg2, arg3, arg4, arg5); + } + template <typename T1, typename T2, typename T3, typename T4> + hash_code combine(const T1 &arg1, const T2 &arg2, const T3 &arg3, + const T4 &arg4) { + combine_data(get_hashable_data(arg1)); + return combine(arg2, arg3, arg4); + } + template <typename T1, typename T2, typename T3> + hash_code combine(const T1 &arg1, const T2 &arg2, const T3 &arg3) { + combine_data(get_hashable_data(arg1)); + return combine(arg2, arg3); + } + template <typename T1, typename T2> + hash_code combine(const T1 &arg1, const T2 &arg2) { + combine_data(get_hashable_data(arg1)); + return combine(arg2); + } + template <typename T1> + hash_code combine(const T1 &arg1) { + combine_data(get_hashable_data(arg1)); + return combine(); + } + +#endif + + /// \brief Base case for recursive, variadic combining. + /// + /// The base case when combining arguments recursively is reached when all + /// arguments have been handled. It flushes the remaining buffer and + /// constructs a hash_code. + hash_code combine() { + // Check whether the entire set of values fit in the buffer. If so, we'll + // use the optimized short hashing routine and skip state entirely. + if (length == 0) + return hash_short(buffer, buffer_ptr - buffer, seed); + + // Mix the final buffer, rotating it if we did a partial fill in order to + // simulate doing a mix of the last 64-bytes. That is how the algorithm + // works when we have a contiguous byte sequence, and we want to emulate + // that here. + std::rotate(buffer, buffer_ptr, buffer_end); + + // Mix this chunk into the current state. + state.mix(buffer); + length += buffer_ptr - buffer; + + return state.finalize(length); } }; -} // end namespace llvm +} // namespace detail +} // namespace hashing + + +#if __has_feature(__cxx_variadic_templates__) + +/// \brief Combine values into a single hash_code. +/// +/// This routine accepts a varying number of arguments of any type. It will +/// attempt to combine them into a single hash_code. For user-defined types it +/// attempts to call a \see hash_value overload (via ADL) for the type. For +/// integer and pointer types it directly combines their data into the +/// resulting hash_code. +/// +/// The result is suitable for returning from a user's hash_value +/// *implementation* for their user-defined type. Consumers of a type should +/// *not* call this routine, they should instead call 'hash_value'. +template <typename ...Ts> hash_code hash_combine(const Ts &...args) { + // Recursively hash each argument using a helper class. + ::llvm::hashing::detail::hash_combine_recursive_helper helper; + return helper.combine(args...); +} + +#else + +// What follows are manually exploded overloads for each argument width. See +// the above variadic definition for documentation and specification. + +template <typename T1, typename T2, typename T3, typename T4, typename T5, + typename T6> +hash_code hash_combine(const T1 &arg1, const T2 &arg2, const T3 &arg3, + const T4 &arg4, const T5 &arg5, const T6 &arg6) { + ::llvm::hashing::detail::hash_combine_recursive_helper helper; + return helper.combine(arg1, arg2, arg3, arg4, arg5, arg6); +} +template <typename T1, typename T2, typename T3, typename T4, typename T5> +hash_code hash_combine(const T1 &arg1, const T2 &arg2, const T3 &arg3, + const T4 &arg4, const T5 &arg5) { + ::llvm::hashing::detail::hash_combine_recursive_helper helper; + return helper.combine(arg1, arg2, arg3, arg4, arg5); +} +template <typename T1, typename T2, typename T3, typename T4> +hash_code hash_combine(const T1 &arg1, const T2 &arg2, const T3 &arg3, + const T4 &arg4) { + ::llvm::hashing::detail::hash_combine_recursive_helper helper; + return helper.combine(arg1, arg2, arg3, arg4); +} +template <typename T1, typename T2, typename T3> +hash_code hash_combine(const T1 &arg1, const T2 &arg2, const T3 &arg3) { + ::llvm::hashing::detail::hash_combine_recursive_helper helper; + return helper.combine(arg1, arg2, arg3); +} +template <typename T1, typename T2> +hash_code hash_combine(const T1 &arg1, const T2 &arg2) { + ::llvm::hashing::detail::hash_combine_recursive_helper helper; + return helper.combine(arg1, arg2); +} +template <typename T1> +hash_code hash_combine(const T1 &arg1) { + ::llvm::hashing::detail::hash_combine_recursive_helper helper; + return helper.combine(arg1); +} + +#endif + +} // namespace llvm #endif diff --git a/include/llvm/Support/system_error.h b/include/llvm/Support/system_error.h index b309732..af81206 100644 --- a/include/llvm/Support/system_error.h +++ b/include/llvm/Support/system_error.h @@ -470,17 +470,6 @@ template <> struct hash<std::error_code>; namespace llvm { -template <class T, T v> -struct integral_constant { - typedef T value_type; - static const value_type value = v; - typedef integral_constant<T,v> type; - operator value_type() { return value; } -}; - -typedef integral_constant<bool, true> true_type; -typedef integral_constant<bool, false> false_type; - // is_error_code_enum template <class Tp> struct is_error_code_enum : public false_type {}; diff --git a/include/llvm/Support/type_traits.h b/include/llvm/Support/type_traits.h index 515295b..03f85e9 100644 --- a/include/llvm/Support/type_traits.h +++ b/include/llvm/Support/type_traits.h @@ -17,6 +17,7 @@ #ifndef LLVM_SUPPORT_TYPE_TRAITS_H #define LLVM_SUPPORT_TYPE_TRAITS_H +#include "llvm/Support/DataTypes.h" #include <utility> // This is actually the conforming implementation which works with abstract @@ -68,17 +69,62 @@ struct isPodLike<std::pair<T, U> > { }; +template <class T, T v> +struct integral_constant { + typedef T value_type; + static const value_type value = v; + typedef integral_constant<T,v> type; + operator value_type() { return value; } +}; + +typedef integral_constant<bool, true> true_type; +typedef integral_constant<bool, false> false_type; + /// \brief Metafunction that determines whether the two given types are /// equivalent. -template<typename T, typename U> -struct is_same { - static const bool value = false; -}; +template<typename T, typename U> struct is_same : public false_type {}; +template<typename T> struct is_same<T, T> : public true_type {}; + +/// \brief Metafunction that removes const qualification from a type. +template <typename T> struct remove_const { typedef T type; }; +template <typename T> struct remove_const<const T> { typedef T type; }; -template<typename T> -struct is_same<T, T> { - static const bool value = true; +/// \brief Metafunction that removes volatile qualification from a type. +template <typename T> struct remove_volatile { typedef T type; }; +template <typename T> struct remove_volatile<volatile T> { typedef T type; }; + +/// \brief Metafunction that removes both const and volatile qualification from +/// a type. +template <typename T> struct remove_cv { + typedef typename remove_const<typename remove_volatile<T>::type>::type type; }; + +/// \brief Helper to implement is_integral metafunction. +template <typename T> struct is_integral_impl : false_type {}; +template <> struct is_integral_impl< bool> : true_type {}; +template <> struct is_integral_impl< char> : true_type {}; +template <> struct is_integral_impl< signed char> : true_type {}; +template <> struct is_integral_impl<unsigned char> : true_type {}; +template <> struct is_integral_impl< wchar_t> : true_type {}; +template <> struct is_integral_impl< short> : true_type {}; +template <> struct is_integral_impl<unsigned short> : true_type {}; +template <> struct is_integral_impl< int> : true_type {}; +template <> struct is_integral_impl<unsigned int> : true_type {}; +template <> struct is_integral_impl< long> : true_type {}; +template <> struct is_integral_impl<unsigned long> : true_type {}; +template <> struct is_integral_impl< long long> : true_type {}; +template <> struct is_integral_impl<unsigned long long> : true_type {}; + +/// \brief Metafunction that determines whether the given type is an integral +/// type. +template <typename T> +struct is_integral : is_integral_impl<T> {}; + +/// \brief Metafunction that determines whether the given type is a pointer +/// type. +template <typename T> struct is_pointer : false_type {}; +template <typename T> struct is_pointer<T*> : true_type {}; + // enable_if_c - Enable/disable a template based on a metafunction template<bool Cond, typename T = void> diff --git a/lib/Support/CMakeLists.txt b/lib/Support/CMakeLists.txt index 6cec47d..0b69238 100644 --- a/lib/Support/CMakeLists.txt +++ b/lib/Support/CMakeLists.txt @@ -26,6 +26,7 @@ add_llvm_library(LLVMSupport FoldingSet.cpp FormattedStream.cpp GraphWriter.cpp + Hashing.cpp IntEqClasses.cpp IntervalMap.cpp IntrusiveRefCntPtr.cpp diff --git a/lib/VMCore/LLVMContextImpl.h b/lib/VMCore/LLVMContextImpl.h index 9aba737..a29bba2 100644 --- a/lib/VMCore/LLVMContextImpl.h +++ b/lib/VMCore/LLVMContextImpl.h @@ -119,10 +119,9 @@ struct AnonStructTypeKeyInfo { return DenseMapInfo<StructType*>::getTombstoneKey(); } static unsigned getHashValue(const KeyTy& Key) { - GeneralHash Hash; - Hash.add(Key.ETypes); - Hash.add(Key.isPacked); - return Hash.finish(); + return hash_combine(hash_combine_range(Key.ETypes.begin(), + Key.ETypes.end()), + Key.isPacked); } static unsigned getHashValue(const StructType *ST) { return getHashValue(KeyTy(ST)); @@ -172,11 +171,10 @@ struct FunctionTypeKeyInfo { return DenseMapInfo<FunctionType*>::getTombstoneKey(); } static unsigned getHashValue(const KeyTy& Key) { - GeneralHash Hash; - Hash.add(Key.ReturnType); - Hash.add(Key.Params); - Hash.add(Key.isVarArg); - return Hash.finish(); + return hash_combine(Key.ReturnType, + hash_combine_range(Key.Params.begin(), + Key.Params.end()), + Key.isVarArg); } static unsigned getHashValue(const FunctionType *FT) { return getHashValue(KeyTy(FT)); diff --git a/unittests/ADT/HashingTest.cpp b/unittests/ADT/HashingTest.cpp index 18bfb72..1f4e479 100644 --- a/unittests/ADT/HashingTest.cpp +++ b/unittests/ADT/HashingTest.cpp @@ -13,45 +13,306 @@ #include "gtest/gtest.h" #include "llvm/ADT/Hashing.h" +#include "llvm/Support/DataTypes.h" +#include <deque> +#include <list> +#include <map> +#include <vector> + +namespace llvm { + +// Helper for test code to print hash codes. +void PrintTo(const hash_code &code, std::ostream *os) { + *os << static_cast<size_t>(code); +} + +// Fake an object that is recognized as hashable data to test super large +// objects. +struct LargeTestInteger { uint64_t arr[8]; }; + +namespace hashing { +namespace detail { +template <> struct is_hashable_data<LargeTestInteger> : true_type {}; +} // namespace detail +} // namespace hashing + +} // namespace llvm using namespace llvm; namespace { -TEST(HashingTest, EmptyHashTest) { - GeneralHash Hash; - ASSERT_EQ(0u, Hash.finish()); +TEST(HashingTest, HashValueBasicTest) { + int x = 42, y = 43, c = 'x'; + void *p = 0; + uint64_t i = 71; + const unsigned ci = 71; + volatile int vi = 71; + const volatile int cvi = 71; + uintptr_t addr = reinterpret_cast<uintptr_t>(&y); + EXPECT_EQ(hash_value(42), hash_value(x)); + EXPECT_NE(hash_value(42), hash_value(y)); + EXPECT_NE(hash_value(42), hash_value(p)); + EXPECT_NE(hash_code::get_null_code(), hash_value(p)); + EXPECT_EQ(hash_value(71), hash_value(i)); + EXPECT_EQ(hash_value(71), hash_value(ci)); + EXPECT_EQ(hash_value(71), hash_value(vi)); + EXPECT_EQ(hash_value(71), hash_value(cvi)); + EXPECT_EQ(hash_value(c), hash_value('x')); + EXPECT_EQ(hash_value('4'), hash_value('0' + 4)); + EXPECT_EQ(hash_value(addr), hash_value(&y)); } -TEST(HashingTest, IntegerHashTest) { - ASSERT_TRUE(GeneralHash().add(1).finish() == GeneralHash().add(1).finish()); - ASSERT_TRUE(GeneralHash().add(1).finish() != GeneralHash().add(2).finish()); -} +template <typename T, size_t N> T *begin(T (&arr)[N]) { return arr; } +template <typename T, size_t N> T *end(T (&arr)[N]) { return arr + N; } + +// Provide a dummy, hashable type designed for easy verification: its hash is +// the same as its value. +struct HashableDummy { size_t value; }; +hash_code hash_value(HashableDummy dummy) { return dummy.value; } + +TEST(HashingTest, HashCombineRangeBasicTest) { + // Leave this uninitialized in the hope that valgrind will catch bad reads. + int dummy; + hash_code dummy_hash = hash_combine_range(&dummy, &dummy); + EXPECT_NE(hash_code::get_null_code(), dummy_hash); + EXPECT_NE(hash_code::get_invalid_code(), dummy_hash); + + const int arr1[] = { 1, 2, 3 }; + hash_code arr1_hash = hash_combine_range(begin(arr1), end(arr1)); + EXPECT_NE(hash_code::get_null_code(), arr1_hash); + EXPECT_NE(hash_code::get_invalid_code(), arr1_hash); + EXPECT_NE(dummy_hash, arr1_hash); + EXPECT_EQ(arr1_hash, hash_combine_range(begin(arr1), end(arr1))); -TEST(HashingTest, StringHashTest) { - ASSERT_TRUE( - GeneralHash().add("abc").finish() == GeneralHash().add("abc").finish()); - ASSERT_TRUE( - GeneralHash().add("abc").finish() != GeneralHash().add("abcd").finish()); + const std::vector<int> vec(begin(arr1), end(arr1)); + EXPECT_EQ(arr1_hash, hash_combine_range(vec.begin(), vec.end())); + + const std::list<int> list(begin(arr1), end(arr1)); + EXPECT_EQ(arr1_hash, hash_combine_range(list.begin(), list.end())); + + const std::deque<int> deque(begin(arr1), end(arr1)); + EXPECT_EQ(arr1_hash, hash_combine_range(deque.begin(), deque.end())); + + const int arr2[] = { 3, 2, 1 }; + hash_code arr2_hash = hash_combine_range(begin(arr2), end(arr2)); + EXPECT_NE(hash_code::get_null_code(), arr2_hash); + EXPECT_NE(hash_code::get_invalid_code(), arr2_hash); + EXPECT_NE(dummy_hash, arr2_hash); + EXPECT_NE(arr1_hash, arr2_hash); + + const int arr3[] = { 1, 1, 2, 3 }; + hash_code arr3_hash = hash_combine_range(begin(arr3), end(arr3)); + EXPECT_NE(hash_code::get_null_code(), arr3_hash); + EXPECT_NE(hash_code::get_invalid_code(), arr3_hash); + EXPECT_NE(dummy_hash, arr3_hash); + EXPECT_NE(arr1_hash, arr3_hash); + + const int arr4[] = { 1, 2, 3, 3 }; + hash_code arr4_hash = hash_combine_range(begin(arr4), end(arr4)); + EXPECT_NE(hash_code::get_null_code(), arr4_hash); + EXPECT_NE(hash_code::get_invalid_code(), arr4_hash); + EXPECT_NE(dummy_hash, arr4_hash); + EXPECT_NE(arr1_hash, arr4_hash); + + const size_t arr5[] = { 1, 2, 3 }; + const HashableDummy d_arr5[] = { {1}, {2}, {3} }; + hash_code arr5_hash = hash_combine_range(begin(arr5), end(arr5)); + hash_code d_arr5_hash = hash_combine_range(begin(d_arr5), end(d_arr5)); + EXPECT_EQ(arr5_hash, d_arr5_hash); } -TEST(HashingTest, FloatHashTest) { - ASSERT_TRUE( - GeneralHash().add(1.0f).finish() == GeneralHash().add(1.0f).finish()); - ASSERT_TRUE( - GeneralHash().add(1.0f).finish() != GeneralHash().add(2.0f).finish()); +TEST(HashingTest, HashCombineRangeLengthDiff) { + // Test that as only the length varies, we compute different hash codes for + // sequences. + std::map<size_t, size_t> code_to_size; + std::vector<char> all_one_c(256, '\xff'); + for (unsigned Idx = 1, Size = all_one_c.size(); Idx < Size; ++Idx) { + hash_code code = hash_combine_range(&all_one_c[0], &all_one_c[0] + Idx); + std::map<size_t, size_t>::iterator + I = code_to_size.insert(std::make_pair(code, Idx)).first; + EXPECT_EQ(Idx, I->second); + } + code_to_size.clear(); + std::vector<char> all_zero_c(256, '\0'); + for (unsigned Idx = 1, Size = all_zero_c.size(); Idx < Size; ++Idx) { + hash_code code = hash_combine_range(&all_zero_c[0], &all_zero_c[0] + Idx); + std::map<size_t, size_t>::iterator + I = code_to_size.insert(std::make_pair(code, Idx)).first; + EXPECT_EQ(Idx, I->second); + } + code_to_size.clear(); + std::vector<unsigned> all_one_int(512, -1); + for (unsigned Idx = 1, Size = all_one_int.size(); Idx < Size; ++Idx) { + hash_code code = hash_combine_range(&all_one_int[0], &all_one_int[0] + Idx); + std::map<size_t, size_t>::iterator + I = code_to_size.insert(std::make_pair(code, Idx)).first; + EXPECT_EQ(Idx, I->second); + } + code_to_size.clear(); + std::vector<unsigned> all_zero_int(512, 0); + for (unsigned Idx = 1, Size = all_zero_int.size(); Idx < Size; ++Idx) { + hash_code code = hash_combine_range(&all_zero_int[0], &all_zero_int[0] + Idx); + std::map<size_t, size_t>::iterator + I = code_to_size.insert(std::make_pair(code, Idx)).first; + EXPECT_EQ(Idx, I->second); + } } -TEST(HashingTest, DoubleHashTest) { - ASSERT_TRUE(GeneralHash().add(1.).finish() == GeneralHash().add(1.).finish()); - ASSERT_TRUE(GeneralHash().add(1.).finish() != GeneralHash().add(2.).finish()); +TEST(HashingTest, HashCombineRangeGoldenTest) { + struct { const char *s; uint64_t hash; } golden_data[] = { + { "a", 0xaeb6f9d5517c61f8ULL }, + { "ab", 0x7ab1edb96be496b4ULL }, + { "abc", 0xe38e60bf19c71a3fULL }, + { "abcde", 0xd24461a66de97f6eULL }, + { "abcdefgh", 0x4ef872ec411dec9dULL }, + { "abcdefghijklm", 0xe8a865539f4eadfeULL }, + { "abcdefghijklmnopqrstu", 0x261cdf85faaf4e79ULL }, + { "abcdefghijklmnopqrstuvwxyzabcdef", 0x43ba70e4198e3b2aULL }, + { "abcdefghijklmnopqrstuvwxyzabcdef" + "abcdefghijklmnopqrstuvwxyzghijkl" + "abcdefghijklmnopqrstuvwxyzmnopqr" + "abcdefghijklmnopqrstuvwxyzstuvwx" + "abcdefghijklmnopqrstuvwxyzyzabcd", 0xdcd57fb2afdf72beULL }, + { "a", 0xaeb6f9d5517c61f8ULL }, + { "aa", 0xf2b3b69a9736a1ebULL }, + { "aaa", 0xf752eb6f07b1cafeULL }, + { "aaaaa", 0x812bd21e1236954cULL }, + { "aaaaaaaa", 0xff07a2cff08ac587ULL }, + { "aaaaaaaaaaaaa", 0x84ac949d54d704ecULL }, + { "aaaaaaaaaaaaaaaaaaaaa", 0xcb2c8fb6be8f5648ULL }, + { "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 0xcc40ab7f164091b6ULL }, + { "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" + "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" + "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" + "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" + "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 0xc58e174c1e78ffe9ULL }, + { "z", 0x1ba160d7e8f8785cULL }, + { "zz", 0x2c5c03172f1285d7ULL }, + { "zzz", 0x9d2c4f4b507a2ac3ULL }, + { "zzzzz", 0x0f03b9031735693aULL }, + { "zzzzzzzz", 0xe674147c8582c08eULL }, + { "zzzzzzzzzzzzz", 0x3162d9fa6938db83ULL }, + { "zzzzzzzzzzzzzzzzzzzzz", 0x37b9a549e013620cULL }, + { "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz", 0x8921470aff885016ULL }, + { "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz" + "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz" + "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz" + "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz" + "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz", 0xf60fdcd9beb08441ULL }, + { "a", 0xaeb6f9d5517c61f8ULL }, + { "ab", 0x7ab1edb96be496b4ULL }, + { "aba", 0x3edb049950884d0aULL }, + { "ababa", 0x8f2de9e73a97714bULL }, + { "abababab", 0xee14a29ddf0ce54cULL }, + { "ababababababa", 0x38b3ddaada2d52b4ULL }, + { "ababababababababababa", 0xd3665364219f2b85ULL }, + { "abababababababababababababababab" + "abababababababababababababababab" + "abababababababababababababababab" + "abababababababababababababababab" + "abababababababababababababababab", 0x840192d129f7a22bULL } + }; + for (unsigned i = 0; i < sizeof(golden_data)/sizeof(*golden_data); ++i) { + StringRef str = golden_data[i].s; + hash_code hash = hash_combine_range(str.begin(), str.end()); +#if 0 // Enable this to generate paste-able text for the above structure. + std::string member_str = "\"" + str.str() + "\","; + fprintf(stderr, " { %-35s 0x%016lxULL },\n", + member_str.c_str(), (size_t)hash); +#endif + EXPECT_EQ(static_cast<size_t>(golden_data[i].hash), + static_cast<size_t>(hash)); + } } -TEST(HashingTest, IntegerArrayHashTest) { - int a[] = { 1, 2 }; - int b[] = { 1, 3 }; - ASSERT_TRUE(GeneralHash().add(a).finish() == GeneralHash().add(a).finish()); - ASSERT_TRUE(GeneralHash().add(a).finish() != GeneralHash().add(b).finish()); +TEST(HashingTest, HashCombineBasicTest) { + // Hashing a sequence of homogenous types matches range hashing. + const int i1 = 42, i2 = 43, i3 = 123, i4 = 999, i5 = 0, i6 = 79; + const int arr1[] = { i1, i2, i3, i4, i5, i6 }; + EXPECT_EQ(hash_combine_range(arr1, arr1 + 1), hash_combine(i1)); + EXPECT_EQ(hash_combine_range(arr1, arr1 + 2), hash_combine(i1, i2)); + EXPECT_EQ(hash_combine_range(arr1, arr1 + 3), hash_combine(i1, i2, i3)); + EXPECT_EQ(hash_combine_range(arr1, arr1 + 4), hash_combine(i1, i2, i3, i4)); + EXPECT_EQ(hash_combine_range(arr1, arr1 + 5), + hash_combine(i1, i2, i3, i4, i5)); + EXPECT_EQ(hash_combine_range(arr1, arr1 + 6), + hash_combine(i1, i2, i3, i4, i5, i6)); + + // Hashing a sequence of heterogenous types which *happen* to all produce the + // same data for hashing produces the same as a range-based hash of the + // fundamental values. + const size_t s1 = 1024, s2 = 8888, s3 = 9000000; + const HashableDummy d1 = { 1024 }, d2 = { 8888 }, d3 = { 9000000 }; + const size_t arr2[] = { s1, s2, s3 }; + EXPECT_EQ(hash_combine_range(begin(arr2), end(arr2)), + hash_combine(s1, s2, s3)); + EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(s1, s2, d3)); + EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(s1, d2, s3)); + EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(d1, s2, s3)); + EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(d1, d2, s3)); + EXPECT_EQ(hash_combine(s1, s2, s3), hash_combine(d1, d2, d3)); + + // Permuting values causes hashes to change. + EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i1, i1, i2)); + EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i1, i2, i1)); + EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i2, i1, i1)); + EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i2, i2, i1)); + EXPECT_NE(hash_combine(i1, i1, i1), hash_combine(i2, i2, i2)); + EXPECT_NE(hash_combine(i2, i1, i1), hash_combine(i1, i1, i2)); + EXPECT_NE(hash_combine(i1, i1, i2), hash_combine(i1, i2, i1)); + EXPECT_NE(hash_combine(i1, i2, i1), hash_combine(i2, i1, i1)); + + // Changing type w/o changing value causes hashes to change. + EXPECT_NE(hash_combine(i1, i2, i3), hash_combine((char)i1, i2, i3)); + EXPECT_NE(hash_combine(i1, i2, i3), hash_combine(i1, (char)i2, i3)); + EXPECT_NE(hash_combine(i1, i2, i3), hash_combine(i1, i2, (char)i3)); + + // This is array of uint64, but it should have the exact same byte pattern as + // an array of LargeTestIntegers. + const uint64_t bigarr[] = { + 0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL, + 0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL, + 0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL, + 0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL, + 0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL, + 0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL, + 0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL, + 0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL, + 0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL + }; + // Hash a preposterously large integer, both aligned with the buffer and + // misaligned. + const LargeTestInteger li = { { + 0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL, + 0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, 0xafafafafededededULL, + 0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL + } }; + // Rotate the storage from 'li'. + const LargeTestInteger l2 = { { + 0xacacacacbcbcbcbcULL, 0xccddeeffeeddccbbULL, 0xdeadbeafdeadbeefULL, + 0xfefefefededededeULL, 0xafafafafededededULL, 0xffffeeeeddddccccULL, + 0xaaaacbcbffffababULL, 0xaaaaaaaaababababULL + } }; + const LargeTestInteger l3 = { { + 0xccddeeffeeddccbbULL, 0xdeadbeafdeadbeefULL, 0xfefefefededededeULL, + 0xafafafafededededULL, 0xffffeeeeddddccccULL, 0xaaaacbcbffffababULL, + 0xaaaaaaaaababababULL, 0xacacacacbcbcbcbcULL + } }; + EXPECT_EQ(hash_combine_range(begin(bigarr), end(bigarr)), + hash_combine(li, li, li)); + EXPECT_EQ(hash_combine_range(bigarr, bigarr + 9), + hash_combine(bigarr[0], l2)); + EXPECT_EQ(hash_combine_range(bigarr, bigarr + 10), + hash_combine(bigarr[0], bigarr[1], l3)); + EXPECT_EQ(hash_combine_range(bigarr, bigarr + 17), + hash_combine(li, bigarr[0], l2)); + EXPECT_EQ(hash_combine_range(bigarr, bigarr + 18), + hash_combine(li, bigarr[0], bigarr[1], l3)); + EXPECT_EQ(hash_combine_range(bigarr, bigarr + 18), + hash_combine(bigarr[0], l2, bigarr[9], l3)); + EXPECT_EQ(hash_combine_range(bigarr, bigarr + 20), + hash_combine(bigarr[0], l2, bigarr[9], l3, bigarr[18], bigarr[19])); } } |