1 //===-- llvm/System/DynamicLibrary.h - Portable Dynamic Library -*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Reid Spencer and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the sys::DynamicLibrary class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_SYSTEM_DYNAMIC_LIBRARY_H
15 #define LLVM_SYSTEM_DYNAMIC_LIBRARY_H
17 #include "llvm/System/Path.h"
23 /// This class provides a portable interface to dynamic libraries which also
24 /// might be known as shared libraries, shared objects, dynamic shared
25 /// objects, or dynamic link libraries. Regardless of the terminology or the
26 /// operating system interface, this class provides a portable interface that
27 /// allows dynamic libraries to be loaded and and searched for externally
28 /// defined symbols. This is typically used to provide "plug-in" support.
30 /// @brief Portable dynamic library abstraction.
31 class DynamicLibrary {
32 /// @name Constructors
35 /// Construct a DynamicLibrary that represents the currently executing
36 /// program. The program must have been linked with -export-dynamic or
37 /// -dlopen self for this to work. Any symbols retrieved with the
38 /// GetAddressOfSymbol function will refer to the program not to any
40 /// @throws std::string indicating why the program couldn't be opened.
41 /// @brief Open program as dynamic library.
44 /// This is the constructor for DynamicLibrary instances. It will open
45 /// the dynamic library specified by the \filename Path.
46 /// @throws std::string indicating why the library couldn't be opened.
47 /// @brief Open a dynamic library.
48 DynamicLibrary(const char* filename);
50 /// After destruction, the symbols of the library will no longer be
51 /// available to the program. It is important to make sure the lifespan
52 /// of a DynamicLibrary exceeds the lifetime of the pointers returned
53 /// by the GetAddressOfSymbol otherwise the program may walk off into
54 /// uncharted territory.
55 /// @see GetAddressOfSymbol.
56 /// @brief Closes the DynamicLibrary
63 /// This function allows a library to be loaded without instantiating a
64 /// DynamicLibrary object. Consequently, it is marked as being permanent
65 /// and will only be unloaded when the program terminates.
66 /// @throws std::string on error.
67 /// @brief Open a dynamic library permanently.
68 static void LoadLibraryPermanently(const char* filename);
70 /// This function will search through all previously loaded dynamic
71 /// libraries for the symbol \p symbolName. If it is found, the addressof
72 /// that symbol is returned. If not, null is returned. Note that this will
73 /// search permanently loaded libraries (LoadLibraryPermanently) as well
74 /// as ephemerally loaded libraries (constructors).
75 /// @throws std::string on error.
76 /// @brief Search through libraries for address of a symbol
77 static void* SearchForAddressOfSymbol(const char* symbolName);
79 /// @brief Convenience function for C++ophiles.
80 static void* SearchForAddressOfSymbol(const std::string& symbolName) {
81 return SearchForAddressOfSymbol(symbolName.c_str());
88 /// Looks up a \p symbolName in the DynamicLibrary and returns its address
89 /// if it exists. If the symbol does not exist, returns (void*)0.
90 /// @returns the address of the symbol or 0.
91 /// @brief Get the address of a symbol in the DynamicLibrary.
92 void* GetAddressOfSymbol(const char* symbolName);
94 /// @brief Convenience function for C++ophiles.
95 void* GetAddressOfSymbol(const std::string& symbolName) {
96 return GetAddressOfSymbol(symbolName.c_str());
100 /// @name Implementation
103 void* handle; // Opaque handle for information about the library
105 DynamicLibrary(const DynamicLibrary&); ///< Do not implement
106 DynamicLibrary& operator=(const DynamicLibrary&); ///< Do not implement
110 } // End sys namespace
111 } // End llvm namespace
113 #endif // LLVM_SYSTEM_DYNAMIC_LIBRARY_H