LLVM 20.0.0git
Classes | Functions | Variables
llvm::hashing::detail Namespace Reference

Classes

struct  hash_combine_recursive_helper
 Helper class to manage the recursive combining of hash_combine arguments. More...
 
struct  hash_state
 The intermediate state used during hashing. More...
 
struct  is_hashable_data
 Trait to indicate whether a type's bits can be hashed directly. More...
 
struct  is_hashable_data< std::pair< T, U > >
 

Functions

uint64_t fetch64 (const char *p)
 
uint32_t fetch32 (const char *p)
 
uint64_t rotate (uint64_t val, size_t shift)
 Bitwise right rotate.
 
uint64_t shift_mix (uint64_t val)
 
uint64_t hash_16_bytes (uint64_t low, uint64_t high)
 
uint64_t hash_1to3_bytes (const char *s, size_t len, uint64_t seed)
 
uint64_t hash_4to8_bytes (const char *s, size_t len, uint64_t seed)
 
uint64_t hash_9to16_bytes (const char *s, size_t len, uint64_t seed)
 
uint64_t hash_17to32_bytes (const char *s, size_t len, uint64_t seed)
 
uint64_t hash_33to64_bytes (const char *s, size_t len, uint64_t seed)
 
uint64_t hash_short (const char *s, size_t length, uint64_t seed)
 
uint64_t get_execution_seed ()
 In LLVM_ENABLE_ABI_BREAKING_CHECKS builds, the seed is non-deterministic per process (address of a function in LLVMSupport) to prevent having users depend on the particular hash values.
 
template<typename T >
std::enable_if_t< is_hashable_data< T >::value, Tget_hashable_data (const T &value)
 Helper to get the hashable data representation for a type.
 
template<typename T >
std::enable_if_t<!is_hashable_data< T >::value, size_t > get_hashable_data (const T &value)
 Helper to get the hashable data representation for a type.
 
template<typename T >
bool store_and_advance (char *&buffer_ptr, char *buffer_end, const T &value, size_t offset=0)
 Helper to store data from a value into a buffer and advance the pointer into that buffer.
 
template<typename InputIteratorT >
hash_code hash_combine_range_impl (InputIteratorT first, InputIteratorT last)
 Implement the combining of integral values into a hash_code.
 
template<typename ValueT >
std::enable_if_t< is_hashable_data< ValueT >::value, hash_codehash_combine_range_impl (ValueT *first, ValueT *last)
 Implement the combining of integral values into a hash_code.
 
hash_code hash_integer_value (uint64_t value)
 Helper to hash the value of a single integer.
 
void stable_hash_append (stable_hash &Hash, const char Value)
 
void stable_hash_append (stable_hash &Hash, stable_hash Value)
 

Variables

static constexpr uint64_t k0 = 0xc3a5c85c97cb3127ULL
 Some primes between 2^63 and 2^64 for various uses.
 
static constexpr uint64_t k1 = 0xb492b66fbe98f273ULL
 
static constexpr uint64_t k2 = 0x9ae16a3b2f90404fULL
 
static constexpr uint64_t k3 = 0xc949d7c7509e6557ULL
 
const uint64_t FNV_PRIME_64 = 1099511628211u
 
const uint64_t FNV_OFFSET_64 = 14695981039346656037u
 

Function Documentation

◆ fetch32()

uint32_t llvm::hashing::detail::fetch32 ( const char p)
inline

Definition at line 144 of file Hashing.h.

References llvm::sys::IsBigEndianHost, and llvm::sys::swapByteOrder().

Referenced by hash_4to8_bytes(), and hash_integer_value().

◆ fetch64()

uint64_t llvm::hashing::detail::fetch64 ( const char p)
inline

◆ get_execution_seed()

uint64_t llvm::hashing::detail::get_execution_seed ( )
inline

In LLVM_ENABLE_ABI_BREAKING_CHECKS builds, the seed is non-deterministic per process (address of a function in LLVMSupport) to prevent having users depend on the particular hash values.

On platforms without ASLR, this is still likely non-deterministic per build.

Definition at line 313 of file Hashing.h.

References llvm::install_fatal_error_handler().

Referenced by hash_combine_range_impl(), and hash_integer_value().

◆ get_hashable_data() [1/2]

template<typename T >
std::enable_if_t< is_hashable_data< T >::value, T > llvm::hashing::detail::get_hashable_data ( const T value)

Helper to get the hashable data representation for a type.

This variant is enabled when the type itself can be used.

Definition at line 357 of file Hashing.h.

References value.

Referenced by llvm::hashing::detail::hash_combine_recursive_helper::combine(), and hash_combine_range_impl().

◆ get_hashable_data() [2/2]

template<typename T >
std::enable_if_t<!is_hashable_data< T >::value, size_t > llvm::hashing::detail::get_hashable_data ( const T value)

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.

Definition at line 365 of file Hashing.h.

References llvm::hash_value(), and value.

◆ hash_16_bytes()

uint64_t llvm::hashing::detail::hash_16_bytes ( uint64_t  low,
uint64_t  high 
)
inline

◆ hash_17to32_bytes()

uint64_t llvm::hashing::detail::hash_17to32_bytes ( const char s,
size_t  len,
uint64_t  seed 
)
inline

Definition at line 201 of file Hashing.h.

References fetch64(), hash_16_bytes(), k0, k1, k2, and k3.

Referenced by hash_short().

◆ hash_1to3_bytes()

uint64_t llvm::hashing::detail::hash_1to3_bytes ( const char s,
size_t  len,
uint64_t  seed 
)
inline

Definition at line 181 of file Hashing.h.

References k2, k3, and shift_mix().

Referenced by hash_short().

◆ hash_33to64_bytes()

uint64_t llvm::hashing::detail::hash_33to64_bytes ( const char s,
size_t  len,
uint64_t  seed 
)
inline

Definition at line 211 of file Hashing.h.

References fetch64(), k0, k2, and shift_mix().

Referenced by hash_short().

◆ hash_4to8_bytes()

uint64_t llvm::hashing::detail::hash_4to8_bytes ( const char s,
size_t  len,
uint64_t  seed 
)
inline

Definition at line 190 of file Hashing.h.

References fetch32(), and hash_16_bytes().

Referenced by hash_short().

◆ hash_9to16_bytes()

uint64_t llvm::hashing::detail::hash_9to16_bytes ( const char s,
size_t  len,
uint64_t  seed 
)
inline

Definition at line 195 of file Hashing.h.

References fetch64(), hash_16_bytes(), and rotate().

Referenced by hash_short().

◆ hash_combine_range_impl() [1/2]

template<typename InputIteratorT >
hash_code llvm::hashing::detail::hash_combine_range_impl ( InputIteratorT  first,
InputIteratorT  last 
)

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.

Definition at line 395 of file Hashing.h.

References assert(), llvm::hashing::detail::hash_state::create(), llvm::hashing::detail::hash_state::finalize(), get_execution_seed(), get_hashable_data(), hash_short(), llvm::hashing::detail::hash_state::mix(), and store_and_advance().

◆ hash_combine_range_impl() [2/2]

template<typename ValueT >
std::enable_if_t< is_hashable_data< ValueT >::value, hash_code > llvm::hashing::detail::hash_combine_range_impl ( ValueT first,
ValueT last 
)

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.

Definition at line 439 of file Hashing.h.

References llvm::hashing::detail::hash_state::create(), get_execution_seed(), and hash_short().

◆ hash_integer_value()

hash_code llvm::hashing::detail::hash_integer_value ( uint64_t  value)
inline

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.

Definition at line 609 of file Hashing.h.

References fetch32(), get_execution_seed(), hash_16_bytes(), and value.

◆ hash_short()

uint64_t llvm::hashing::detail::hash_short ( const char s,
size_t  length,
uint64_t  seed 
)
inline

◆ rotate()

uint64_t llvm::hashing::detail::rotate ( uint64_t  val,
size_t  shift 
)
inline

Bitwise right rotate.

Normally this will compile to a single instruction, especially if the shift is a manifest constant.

Definition at line 161 of file Hashing.h.

Referenced by hash_9to16_bytes().

◆ shift_mix()

uint64_t llvm::hashing::detail::shift_mix ( uint64_t  val)
inline

◆ stable_hash_append() [1/2]

void llvm::hashing::detail::stable_hash_append ( stable_hash Hash,
const char  Value 
)
inline

◆ stable_hash_append() [2/2]

void llvm::hashing::detail::stable_hash_append ( stable_hash Hash,
stable_hash  Value 
)
inline

Definition at line 41 of file StableHashing.h.

References I, and stable_hash_append().

◆ store_and_advance()

template<typename T >
bool llvm::hashing::detail::store_and_advance ( char *&  buffer_ptr,
char buffer_end,
const T value,
size_t  offset = 0 
)

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.

Definition at line 378 of file Hashing.h.

References value.

Referenced by llvm::hashing::detail::hash_combine_recursive_helper::combine_data(), and hash_combine_range_impl().

Variable Documentation

◆ FNV_OFFSET_64

const uint64_t llvm::hashing::detail::FNV_OFFSET_64 = 14695981039346656037u

◆ FNV_PRIME_64

const uint64_t llvm::hashing::detail::FNV_PRIME_64 = 1099511628211u

Definition at line 33 of file StableHashing.h.

Referenced by stable_hash_append().

◆ k0

constexpr uint64_t llvm::hashing::detail::k0 = 0xc3a5c85c97cb3127ULL
staticconstexpr

Some primes between 2^63 and 2^64 for various uses.

Definition at line 153 of file Hashing.h.

Referenced by hash_17to32_bytes(), and hash_33to64_bytes().

◆ k1

constexpr uint64_t llvm::hashing::detail::k1 = 0xb492b66fbe98f273ULL
staticconstexpr

◆ k2

constexpr uint64_t llvm::hashing::detail::k2 = 0x9ae16a3b2f90404fULL
staticconstexpr

Definition at line 155 of file Hashing.h.

Referenced by hash_17to32_bytes(), hash_1to3_bytes(), hash_33to64_bytes(), and hash_short().

◆ k3

constexpr uint64_t llvm::hashing::detail::k3 = 0xc949d7c7509e6557ULL
staticconstexpr

Definition at line 156 of file Hashing.h.

Referenced by hash_17to32_bytes(), and hash_1to3_bytes().