"Weak externals" are a mechanism for object files that allows flexibility at link time. A module can contain an unresolved external symbol (sym1), but it can also include an auxiliary record that indicates that if sym1 is not present at link time, another external symbol (sym2) is used to resolve references instead. More...

#include <AuxiliaryWeakExternal.hpp>

Inheritance diagram for LIEF::COFF::AuxiliaryWeakExternal:

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Collaboration diagram for LIEF::COFF::AuxiliaryWeakExternal:

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Public Types
enum class	CHARACTERISTICS : uint32_t { SEARCH_NOLIBRARY = 1 , SEARCH_LIBRARY = 2 , SEARCH_ALIAS = 3 , ANTI_DEPENDENCY = 4 }
Public Types inherited from LIEF::COFF::AuxiliarySymbol
enum class	TYPE { UNKNOWN = 0 , CLR_TOKEN , FUNC_DEF , BF_AND_EF , WEAK_EXTERNAL , FILE , SEC_DEF }
	Type discriminator for the subclasses. More...

Public Member Functions
	AuxiliaryWeakExternal ()
	AuxiliaryWeakExternal (uint32_t sym_idx, uint32_t characteristics, std::vector< uint8_t > padding)
	AuxiliaryWeakExternal (const AuxiliaryWeakExternal &)=default
AuxiliaryWeakExternal &	operator= (const AuxiliaryWeakExternal &)=default
	AuxiliaryWeakExternal (AuxiliaryWeakExternal &&)=default
AuxiliaryWeakExternal &	operator= (AuxiliaryWeakExternal &&)=default
std::unique_ptr< AuxiliarySymbol >	clone () const override
uint32_t	sym_idx () const
	The symbol-table index of sym2, the symbol to be linked if sym1 is not found.
CHARACTERISTICS	characteristics () const
span< const uint8_t >	padding () const
std::string	to_string () const override
	~AuxiliaryWeakExternal () override=default
Public Member Functions inherited from LIEF::COFF::AuxiliarySymbol
	AuxiliarySymbol ()=default
	AuxiliarySymbol (std::vector< uint8_t > payload)
	AuxiliarySymbol (const AuxiliarySymbol &)=default
AuxiliarySymbol &	operator= (const AuxiliarySymbol &)=default
	AuxiliarySymbol (AuxiliarySymbol &&)=default
AuxiliarySymbol &	operator= (AuxiliarySymbol &&)=default
	AuxiliarySymbol (TYPE ty)
TYPE	type () const
span< const uint8_t >	payload () const
	For unknown type only, return the raw representation of this symbol.
span< uint8_t >	payload ()
virtual	~AuxiliarySymbol ()=default
template<class T>
const T *	as () const
	Helper to downcast a AuxiliarySymbol into a concrete implementation.
template<class T>
T *	as ()

Static Public Member Functions
static std::unique_ptr< AuxiliaryWeakExternal >	parse (const std::vector< uint8_t > &payload)
static bool	classof (const AuxiliarySymbol *sym)
Static Public Member Functions inherited from LIEF::COFF::AuxiliarySymbol
static std::unique_ptr< AuxiliarySymbol >	parse (Symbol &sym, std::vector< uint8_t > payload)
static TYPE	get_aux_type (const Symbol &sym)

Detailed Description

"Weak externals" are a mechanism for object files that allows flexibility at link time. A module can contain an unresolved external symbol (sym1), but it can also include an auxiliary record that indicates that if sym1 is not present at link time, another external symbol (sym2) is used to resolve references instead.

If a definition of sym1 is linked, then an external reference to the symbol is resolved normally. If a definition of sym1 is not linked, then all references to the weak external for sym1 refer to sym2 instead. The external symbol, sym2, must always be linked; typically, it is defined in the module that contains the weak reference to sym1.

Reference: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#auxiliary-format-3-weak-externals

Member Enumeration Documentation

◆ CHARACTERISTICS

enum class LIEF::COFF::AuxiliaryWeakExternal::CHARACTERISTICS : uint32_t

strong

Enumerator
SEARCH_NOLIBRARY	No library search for sym1 should be performed.
SEARCH_LIBRARY	A library search for sym1 should be performed.
SEARCH_ALIAS	sym1 is an alias for sym2
ANTI_DEPENDENCY