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//===-- llvm/System/DynamicLibrary.h - Portable Dynamic Library -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Reid Spencer and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the sys::DynamicLibrary class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SYSTEM_DYNAMIC_LIBRARY_H
#define LLVM_SYSTEM_DYNAMIC_LIBRARY_H
#include "llvm/System/Path.h"
#include "llvm/System/IncludeFile.h"
#include <string>
namespace llvm {
namespace sys {
/// 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 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.
/// @since 1.4
/// @brief Portable dynamic library abstraction.
class DynamicLibrary {
/// @name Constructors
/// @{
public:
/// Construct a DynamicLibrary that represents the currently executing
/// program. The program must have been linked with -export-dynamic or
/// -dlopen self for this to work. Any symbols retrieved with the
/// GetAddressOfSymbol function will refer to the program not to any
/// library.
/// @throws std::string indicating why the program couldn't be opened.
/// @brief Open program as dynamic library.
DynamicLibrary();
/// This is the constructor for DynamicLibrary instances. It will open
/// the dynamic library specified by the filename Path.
/// @throws std::string indicating why the library couldn't be opened.
/// @brief Open a dynamic library.
DynamicLibrary(const char* filename);
/// After destruction, the symbols of the library will no longer be
/// available to the program. It is important to make sure the lifespan
/// of a DynamicLibrary exceeds the lifetime of the pointers returned
/// by the GetAddressOfSymbol otherwise the program may walk off into
/// uncharted territory.
/// @see GetAddressOfSymbol.
/// @brief Closes the DynamicLibrary
~DynamicLibrary();
/// @}
/// @name Functions
/// @{
public:
/// This function allows a library to be loaded without instantiating a
/// DynamicLibrary object. Consequently, it is marked as being permanent
/// and will only be unloaded when the program terminates. This returns
/// false on success or returns true and fills in *ErrMsg on failure.
/// @brief Open a dynamic library permanently.
static bool LoadLibraryPermanently(const char* filename,
std::string *ErrMsg = 0);
/// This function will search through all previously loaded dynamic
/// libraries for the symbol \p symbolName. If it is found, the addressof
/// that symbol is returned. If not, null is returned. Note that this will
/// search permanently loaded libraries (LoadLibraryPermanently) as well
/// as ephemerally loaded libraries (constructors).
/// @throws std::string on error.
/// @brief Search through libraries for address of a symbol
static void* SearchForAddressOfSymbol(const char* symbolName);
/// @brief Convenience function for C++ophiles.
static void* SearchForAddressOfSymbol(const std::string& symbolName) {
return SearchForAddressOfSymbol(symbolName.c_str());
}
/// This functions permanently adds the symbol \p symbolName with the
/// value \p symbolValue. These symbols are searched before any
/// libraries.
/// @brief Add searchable symbol/value pair.
static void AddSymbol(const char* symbolName, void *symbolValue);
/// @brief Convenience function for C++ophiles.
static void AddSymbol(const std::string& symbolName, void *symbolValue) {
AddSymbol(symbolName.c_str(), symbolValue);
}
/// @}
/// @name Accessors
/// @{
public:
/// Looks up a \p symbolName in the DynamicLibrary and returns its address
/// if it exists. If the symbol does not exist, returns (void*)0.
/// @returns the address of the symbol or 0.
/// @brief Get the address of a symbol in the DynamicLibrary.
void* GetAddressOfSymbol(const char* symbolName);
/// @brief Convenience function for C++ophiles.
void* GetAddressOfSymbol(const std::string& symbolName) {
return GetAddressOfSymbol(symbolName.c_str());
}
/// @}
/// @name Implementation
/// @{
protected:
void* handle; // Opaque handle for information about the library
DynamicLibrary(const DynamicLibrary&); ///< Do not implement
DynamicLibrary& operator=(const DynamicLibrary&); ///< Do not implement
/// @}
};
} // End sys namespace
} // End llvm namespace
FORCE_DEFINING_FILE_TO_BE_LINKED(SystemDynamicLibrary)
#endif // LLVM_SYSTEM_DYNAMIC_LIBRARY_H
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