This class provides a portable interface to dynamic libraries which also might be known as shared libraries, shared objects, dynamic shared objects, or dynamic link libraries. More...

#include "llvm/Support/DynamicLibrary.h"

Classes
class	HandleSet

Public Types
enum	SearchOrdering { SO_Linker , SO_LoadedFirst , SO_LoadedLast , SO_LoadOrder = 4 }

Public Member Functions
	DynamicLibrary (void *data=&Invalid)
void *	getOSSpecificHandle () const
	Return the OS specific handle value.
bool	isValid () const
	Returns true if the object refers to a valid library.
LLVM_ABI void *	getAddressOfSymbol (const char *symbolName)
	Searches through the library for the symbol `symbolName`.

Static Public Member Functions
static LLVM_ABI DynamicLibrary	getPermanentLibrary (const char filename, std::string errMsg=nullptr)
	This function permanently loads the dynamic library at the given path using the library load operation from the host operating system.
static LLVM_ABI DynamicLibrary	addPermanentLibrary (void handle, std::string errMsg=nullptr)
	Registers an externally loaded library.
static bool	LoadLibraryPermanently (const char Filename, std::string ErrMsg=nullptr)
	This function permanently loads the dynamic library at the given path.
static LLVM_ABI DynamicLibrary	getLibrary (const char FileName, std::string Err=nullptr)
	This function loads the dynamic library at the given path, using the library load operation from the host operating system.
static LLVM_ABI void	closeLibrary (DynamicLibrary &Lib)
	This function closes the dynamic library at the given path, using the library close operation of the host operating system, and there is no guarantee if or when this will cause the library to be unloaded.
static LLVM_ABI void *	SearchForAddressOfSymbol (const char *symbolName)
	This function will search through all previously loaded dynamic libraries for the symbol `symbolName`.
static void *	SearchForAddressOfSymbol (const std::string &symbolName)
	Convenience function for C++ophiles.
static LLVM_ABI void	AddSymbol (StringRef symbolName, void *symbolValue)
	This functions permanently adds the symbol `symbolName` with the value `symbolValue`.

Static Public Attributes
static LLVM_ABI SearchOrdering	SearchOrder

Detailed Description

This class provides a portable interface to dynamic libraries which also might be known as shared libraries, shared objects, dynamic shared objects, or dynamic link libraries.

Regardless of the terminology or the operating system interface, this class provides a portable interface that allows dynamic libraries to be loaded and searched for externally defined symbols. This is typically used to provide "plug-in" support. It also allows for symbols to be defined which don't live in any library, but rather the main program itself, useful on Windows where the main executable cannot be searched.

Definition at line 34 of file DynamicLibrary.h.

Member Enumeration Documentation

◆ SearchOrdering

enum llvm::sys::DynamicLibrary::SearchOrdering

Enumerator
SO_Linker	SO_Linker - Search as a call to dlsym(dlopen(NULL)) would when DynamicLibrary::getPermanentLibrary(NULL) has been called or search the list of explcitly loaded symbols if not.
SO_LoadedFirst	SO_LoadedFirst - Search all loaded libraries, then as SO_Linker would.
SO_LoadedLast	SO_LoadedLast - Search as SO_Linker would, then loaded libraries. Only useful to search if libraries with RTLD_LOCAL have been added.
SO_LoadOrder	SO_LoadOrder - Or this in to search libraries in the ordered loaded. The default bahaviour is to search loaded libraries in reverse.

Definition at line 113 of file DynamicLibrary.h.

Constructor & Destructor Documentation

◆ DynamicLibrary()

llvm::sys::DynamicLibrary::DynamicLibrary ( void * data = &Invalid )

inlineexplicit

Definition at line 44 of file DynamicLibrary.h.

References data.

Referenced by addPermanentLibrary(), closeLibrary(), getLibrary(), and getPermanentLibrary().

Member Function Documentation

◆ addPermanentLibrary()

DynamicLibrary DynamicLibrary::addPermanentLibrary	(	void *	handle,
		std::string *	errMsg = nullptr )

static

Registers an externally loaded library.

The library will be unloaded when the program terminates.

It is safe to call this function multiple times for the same library, though ownership is only taken if there was no error.

Definition at line 177 of file DynamicLibrary.cpp.

References DynamicLibrary(), and G.

◆ AddSymbol()

void DynamicLibrary::AddSymbol	(	StringRef	symbolName,
		void *	symbolValue )

static

This functions permanently adds the symbol symbolName with the value symbolValue.

These symbols are searched before any libraries. Add searchable symbol/value pair.

Definition at line 159 of file DynamicLibrary.cpp.

References G.

Referenced by LLVMAddSymbol().

◆ closeLibrary()

void DynamicLibrary::closeLibrary ( DynamicLibrary & Lib )

static

This function closes the dynamic library at the given path, using the library close operation of the host operating system, and there is no guarantee if or when this will cause the library to be unloaded.

This function should be called only if the library was loaded using the getLibrary() function.

Definition at line 203 of file DynamicLibrary.cpp.

References DynamicLibrary(), G, and llvm::Lib.

◆ getAddressOfSymbol()

void * DynamicLibrary::getAddressOfSymbol ( const char * symbolName )

Searches through the library for the symbol symbolName.

If it is found, the address of that symbol is returned. If not, NULL is returned. Note that NULL will also be returned if the library failed to load. Use isValid() to distinguish these cases if it is important. Note that this will not search symbols explicitly registered by AddSymbol().

Definition at line 212 of file DynamicLibrary.cpp.

References llvm::sys::DynamicLibrary::HandleSet::DLSym(), and isValid().

◆ getLibrary()

DynamicLibrary DynamicLibrary::getLibrary	(	const char *	FileName,
		std::string *	Err = nullptr )

static

This function loads the dynamic library at the given path, using the library load operation from the host operating system.

The library instance will be closed when closeLibrary is called or global destructors are run, but there is no guarantee when the library will be unloaded.

This returns a valid DynamicLibrary instance on success and an invalid instance on failure (see isValid()). *Err will only be modified if the library fails to load.

It is safe to call this function multiple times for the same library.

Definition at line 189 of file DynamicLibrary.cpp.

References assert(), llvm::sys::DynamicLibrary::HandleSet::DLOpen(), DynamicLibrary(), and G.

◆ getOSSpecificHandle()

void * llvm::sys::DynamicLibrary::getOSSpecificHandle ( ) const

inline

Return the OS specific handle value.

Definition at line 47 of file DynamicLibrary.h.

◆ getPermanentLibrary()

DynamicLibrary DynamicLibrary::getPermanentLibrary	(	const char *	filename,
		std::string *	errMsg = nullptr )

static

This function permanently loads the dynamic library at the given path using the library load operation from the host operating system.

The library instance will only be closed when global destructors run, and there is no guarantee when the library will be unloaded.

This returns a valid DynamicLibrary instance on success and an invalid instance on failure (see isValid()). *errMsg will only be modified if the library fails to load.

It is safe to call this function multiple times for the same library. Open a dynamic library permanently.

Definition at line 165 of file DynamicLibrary.cpp.

References llvm::sys::DynamicLibrary::HandleSet::DLOpen(), DynamicLibrary(), and G.

Referenced by llvm::orc::DynamicLibrarySearchGenerator::Load(), llvm::PassPlugin::Load(), LoadLibraryPermanently(), and llvm::orc::rt_bootstrap::SimpleExecutorDylibManager::open().

◆ isValid()

bool llvm::sys::DynamicLibrary::isValid ( ) const

inline

Returns true if the object refers to a valid library.

Definition at line 50 of file DynamicLibrary.h.

Referenced by getAddressOfSymbol(), and LoadLibraryPermanently().

◆ LoadLibraryPermanently()

bool llvm::sys::DynamicLibrary::LoadLibraryPermanently	(	const char *	Filename,
		std::string *	ErrMsg = nullptr )

inlinestatic

This function permanently loads the dynamic library at the given path.

Use this instead of getPermanentLibrary() when you won't need to get symbols from the library itself.

It is safe to call this function multiple times for the same library.

Definition at line 87 of file DynamicLibrary.h.

References getPermanentLibrary(), and isValid().

Referenced by llvm::EngineBuilder::create(), llvm::MCJIT::createJIT(), LLVMLoadLibraryPermanently(), and llvm::PluginLoader::operator=().

◆ SearchForAddressOfSymbol() [1/2]

void * DynamicLibrary::SearchForAddressOfSymbol ( const char * symbolName )

static

This function will search through all previously loaded dynamic libraries for the symbol symbolName.

If it is found, the address of that symbol is returned. If not, null is returned. Note that this will search permanently loaded libraries (getPermanentLibrary()) as well as explicitly registered symbols (AddSymbol()).

Exceptions

std::string on error. Search through libraries for address of a symbol

Definition at line 218 of file DynamicLibrary.cpp.

References G, Ptr, llvm::SearchForAddressOfSpecialSymbol(), and SearchOrder.

Referenced by llvm::__deregister_frame(), llvm::Interpreter::callExternalFunction(), llvm::ExecutionEngine::emitGlobals(), llvm::RTDyldMemoryManager::getSymbolAddressInProcess(), LLVMSearchForAddressOfSymbol(), lookupFunction(), and SearchForAddressOfSymbol().