A globally hashed type represents a hash value that is sufficient to uniquely identify a record across multiple type streams or type sequences. More...

#include "llvm/DebugInfo/CodeView/TypeHashing.h"

Public Member Functions
	GloballyHashedType ()=default
	GloballyHashedType (StringRef H)
	GloballyHashedType (ArrayRef< uint8_t > H)
bool	empty () const

Static Public Member Functions
static LLVM_ABI GloballyHashedType	hashType (ArrayRef< uint8_t > RecordData, ArrayRef< GloballyHashedType > PreviousTypes, ArrayRef< GloballyHashedType > PreviousIds)
	Given a sequence of bytes representing a record, compute a global hash for this record.
static GloballyHashedType	hashType (CVType Type, ArrayRef< GloballyHashedType > PreviousTypes, ArrayRef< GloballyHashedType > PreviousIds)
	Given a sequence of bytes representing a record, compute a global hash for this record.
template<typename Range>
static std::vector< GloballyHashedType >	hashTypes (Range &&Records)
	Given a sequence of combined type and ID records, compute global hashes for each of them, returning the results in a vector of hashed types.
template<typename Range>
static std::vector< GloballyHashedType >	hashIds (Range &&Records, ArrayRef< GloballyHashedType > TypeHashes)
	Given a sequence of combined type and ID records, compute global hashes for each of them, returning the results in a vector of hashed types.
static std::vector< GloballyHashedType >	hashTypeCollection (TypeCollection &Types)

Public Attributes
std::array< uint8_t, 8 >	Hash

Friends
bool	operator== (const GloballyHashedType &L, const GloballyHashedType &R)
bool	operator!= (const GloballyHashedType &L, const GloballyHashedType &R)

Detailed Description

A globally hashed type represents a hash value that is sufficient to uniquely identify a record across multiple type streams or type sequences.

This works by, for any given record A which references B, replacing the TypeIndex that refers to B with a previously-computed global hash for B. As this is a recursive algorithm (e.g. the global hash of B also depends on the global hashes of the types that B refers to), a global hash can uniquely identify that A occurs in another stream that has a completely different graph structure. Although the hash itself is slower to compute, probing is much faster with a globally hashed type, because the hash itself is considered "as good as" the original type. Since type records can be quite large, this makes the equality comparison of the hash much faster than equality comparison of a full record.

Definition at line 81 of file TypeHashing.h.

Constructor & Destructor Documentation

◆ GloballyHashedType() [1/3]

llvm::codeview::GloballyHashedType::GloballyHashedType ( )

default

Referenced by GloballyHashedType(), hashType(), hashTypes(), operator!=, and operator==.

◆ GloballyHashedType() [2/3]

llvm::codeview::GloballyHashedType::GloballyHashedType ( StringRef H )

inline

Definition at line 83 of file TypeHashing.h.

References GloballyHashedType(), and H.

◆ GloballyHashedType() [3/3]

llvm::codeview::GloballyHashedType::GloballyHashedType ( ArrayRef< uint8_t > H )

inline

Definition at line 85 of file TypeHashing.h.

References assert(), H, and Hash.

Member Function Documentation

◆ empty()

bool llvm::codeview::GloballyHashedType::empty ( ) const

inline

Definition at line 91 of file TypeHashing.h.

References Hash.

◆ hashIds()

template<typename Range>

std::vector< GloballyHashedType > llvm::codeview::GloballyHashedType::hashIds	(	Range &&	Records,
		ArrayRef< GloballyHashedType >	TypeHashes )

inlinestatic

Given a sequence of combined type and ID records, compute global hashes for each of them, returning the results in a vector of hashed types.

Definition at line 162 of file TypeHashing.h.

References hashType(), and Range.

◆ hashType() [1/2]

GloballyHashedType GloballyHashedType::hashType	(	ArrayRef< uint8_t >	RecordData,
		ArrayRef< GloballyHashedType >	PreviousTypes,
		ArrayRef< GloballyHashedType >	PreviousIds )

static

Given a sequence of bytes representing a record, compute a global hash for this record.

Due to the nature of global hashes incorporating the hashes of referenced records, this function requires a list of types and ids that RecordData might reference, indexable by TypeIndex.

Definition at line 33 of file TypeHashing.cpp.

References llvm::ArrayRef(), llvm::codeview::discoverTypeIndices(), llvm::ArrayRef< T >::drop_front(), llvm::TruncatedBLAKE3< NumBytes >::final(), llvm::codeview::IndexRef, llvm::BLAKE3::init(), llvm::Ref, llvm::ArrayRef< T >::slice(), llvm::ArrayRef< T >::take_front(), and llvm::BLAKE3::update().

Referenced by hashIds(), hashType(), hashTypeCollection(), hashTypes(), llvm::codeview::GlobalTypeTableBuilder::insertRecordBytes(), and llvm::codeview::GlobalTypeTableBuilder::replaceType().

◆ hashType() [2/2]

GloballyHashedType llvm::codeview::GloballyHashedType::hashType	(	CVType	Type,
		ArrayRef< GloballyHashedType >	PreviousTypes,
		ArrayRef< GloballyHashedType >	PreviousIds )

inlinestatic

Given a sequence of bytes representing a record, compute a global hash for this record.

Due to the nature of global hashes incorporating the hashes of referenced records, this function requires a list of types and ids that RecordData might reference, indexable by TypeIndex.

Definition at line 116 of file TypeHashing.h.

References GloballyHashedType(), and hashType().

◆ hashTypeCollection()

std::vector< GloballyHashedType > llvm::codeview::GloballyHashedType::hashTypeCollection ( TypeCollection & Types )

inlinestatic

Definition at line 171 of file TypeHashing.h.

References hashType().

◆ hashTypes()

template<typename Range>

std::vector< GloballyHashedType > llvm::codeview::GloballyHashedType::hashTypes ( Range && Records )

inlinestatic

Given a sequence of combined type and ID records, compute global hashes for each of them, returning the results in a vector of hashed types.

Definition at line 125 of file TypeHashing.h.

References GloballyHashedType(), H, hashType(), and Range.

◆ operator!=

bool operator!=	(	const GloballyHashedType &	L,
		const GloballyHashedType &	R )

friend

Definition at line 98 of file TypeHashing.h.

References GloballyHashedType().

◆ operator==

bool operator==	(	const GloballyHashedType &	L,
		const GloballyHashedType &	R )

friend

Definition at line 93 of file TypeHashing.h.

References GloballyHashedType().

Member Data Documentation

◆ Hash

std::array<uint8_t, 8> llvm::codeview::GloballyHashedType::Hash

Definition at line 89 of file TypeHashing.h.

Referenced by empty(), llvm::DenseMapInfo< codeview::GloballyHashedType >::getHashValue(), and GloballyHashedType().

The documentation for this struct was generated from the following files:

include/llvm/DebugInfo/CodeView/TypeHashing.h
lib/DebugInfo/CodeView/TypeHashing.cpp

Public Member Functions

Static Public Member Functions

Public Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ GloballyHashedType() [1/3]

◆ GloballyHashedType() [2/3]

◆ GloballyHashedType() [3/3]

Member Function Documentation

◆ empty()

◆ hashIds()

◆ hashType() [1/2]

◆ hashType() [2/2]

◆ hashTypeCollection()

◆ hashTypes()

Friends And Related Symbol Documentation

◆ operator!=

◆ operator==

Member Data Documentation

◆ Hash