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, T >	get_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_code >	hash_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.

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

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

Definition at line 136 of file Hashing.h.

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

Referenced by hash_17to32_bytes(), hash_33to64_bytes(), hash_9to16_bytes(), llvm::hashing::detail::hash_state::mix(), and llvm::hashing::detail::hash_state::mix_32_bytes().

◆ 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 354 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 362 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

Definition at line 170 of file Hashing.h.

Referenced by llvm::hashing::detail::hash_state::create(), llvm::hashing::detail::hash_state::finalize(), hash_17to32_bytes(), hash_4to8_bytes(), hash_9to16_bytes(), and hash_integer_value().

◆ 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 392 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 436 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 606 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

Definition at line 234 of file Hashing.h.

References hash_17to32_bytes(), hash_1to3_bytes(), hash_33to64_bytes(), hash_4to8_bytes(), hash_9to16_bytes(), and k2.

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

◆ 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

Definition at line 166 of file Hashing.h.

Referenced by llvm::hashing::detail::hash_state::create(), llvm::hashing::detail::hash_state::finalize(), hash_1to3_bytes(), and hash_33to64_bytes().

◆ 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 375 of file Hashing.h.

References value.

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