1 //===-- DynamicLibrary.cpp - Runtime link/load libraries --------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This header file implements the operating system DynamicLibrary concept. 11 // 12 // FIXME: This file leaks ExplicitSymbols and OpenedHandles! 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "llvm/ADT/StringMap.h" 17 #include "llvm/ADT/DenseSet.h" 18 #include "llvm/Support/DynamicLibrary.h" 19 #include "llvm/Support/Mutex.h" 20 #include "llvm/Config/config.h" 21 #include <cstdio> 22 #include <cstring> 23 24 // Collection of symbol name/value pairs to be searched prior to any libraries. 25 static llvm::StringMap<void *> *ExplicitSymbols = 0; 26 27 namespace { 28 29 struct ExplicitSymbolsDeleter { 30 ~ExplicitSymbolsDeleter() { 31 delete ExplicitSymbols; 32 } 33 }; 34 35 } 36 37 static ExplicitSymbolsDeleter Dummy; 38 39 40 static llvm::sys::SmartMutex<true>& getMutex() { 41 static llvm::sys::SmartMutex<true> HandlesMutex; 42 return HandlesMutex; 43 } 44 45 void llvm::sys::DynamicLibrary::AddSymbol(StringRef symbolName, 46 void *symbolValue) { 47 SmartScopedLock<true> lock(getMutex()); 48 if (ExplicitSymbols == 0) 49 ExplicitSymbols = new llvm::StringMap<void*>(); 50 (*ExplicitSymbols)[symbolName] = symbolValue; 51 } 52 53 char llvm::sys::DynamicLibrary::Invalid = 0; 54 55 #ifdef LLVM_ON_WIN32 56 57 #include "Windows/DynamicLibrary.inc" 58 59 #else 60 61 #if HAVE_DLFCN_H 62 #include <dlfcn.h> 63 using namespace llvm; 64 using namespace llvm::sys; 65 66 //===----------------------------------------------------------------------===// 67 //=== WARNING: Implementation here must contain only TRULY operating system 68 //=== independent code. 69 //===----------------------------------------------------------------------===// 70 71 static DenseSet<void *> *OpenedHandles = 0; 72 73 DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename, 74 std::string *errMsg) { 75 SmartScopedLock<true> lock(getMutex()); 76 77 void *handle = dlopen(filename, RTLD_LAZY|RTLD_GLOBAL); 78 if (handle == 0) { 79 if (errMsg) *errMsg = dlerror(); 80 return DynamicLibrary(); 81 } 82 83 #ifdef __CYGWIN__ 84 // Cygwin searches symbols only in the main 85 // with the handle of dlopen(NULL, RTLD_GLOBAL). 86 if (filename == NULL) 87 handle = RTLD_DEFAULT; 88 #endif 89 90 if (OpenedHandles == 0) 91 OpenedHandles = new DenseSet<void *>(); 92 93 // If we've already loaded this library, dlclose() the handle in order to 94 // keep the internal refcount at +1. 95 if (!OpenedHandles->insert(handle).second) 96 dlclose(handle); 97 98 return DynamicLibrary(handle); 99 } 100 101 void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) { 102 if (!isValid()) 103 return NULL; 104 return dlsym(Data, symbolName); 105 } 106 107 #else 108 109 using namespace llvm; 110 using namespace llvm::sys; 111 112 DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename, 113 std::string *errMsg) { 114 if (errMsg) *errMsg = "dlopen() not supported on this platform"; 115 return DynamicLibrary(); 116 } 117 118 void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) { 119 return NULL; 120 } 121 122 #endif 123 124 namespace llvm { 125 void *SearchForAddressOfSpecialSymbol(const char* symbolName); 126 } 127 128 void* DynamicLibrary::SearchForAddressOfSymbol(const char *symbolName) { 129 SmartScopedLock<true> Lock(getMutex()); 130 131 // First check symbols added via AddSymbol(). 132 if (ExplicitSymbols) { 133 StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName); 134 135 if (i != ExplicitSymbols->end()) 136 return i->second; 137 } 138 139 #if HAVE_DLFCN_H 140 // Now search the libraries. 141 if (OpenedHandles) { 142 for (DenseSet<void *>::iterator I = OpenedHandles->begin(), 143 E = OpenedHandles->end(); I != E; ++I) { 144 //lt_ptr ptr = lt_dlsym(*I, symbolName); 145 void *ptr = dlsym(*I, symbolName); 146 if (ptr) { 147 return ptr; 148 } 149 } 150 } 151 #endif 152 153 if (void *Result = llvm::SearchForAddressOfSpecialSymbol(symbolName)) 154 return Result; 155 156 // This macro returns the address of a well-known, explicit symbol 157 #define EXPLICIT_SYMBOL(SYM) \ 158 if (!strcmp(symbolName, #SYM)) return &SYM 159 160 // On linux we have a weird situation. The stderr/out/in symbols are both 161 // macros and global variables because of standards requirements. So, we 162 // boldly use the EXPLICIT_SYMBOL macro without checking for a #define first. 163 #if defined(__linux__) && !defined(__ANDROID__) 164 { 165 EXPLICIT_SYMBOL(stderr); 166 EXPLICIT_SYMBOL(stdout); 167 EXPLICIT_SYMBOL(stdin); 168 } 169 #else 170 // For everything else, we want to check to make sure the symbol isn't defined 171 // as a macro before using EXPLICIT_SYMBOL. 172 { 173 #ifndef stdin 174 EXPLICIT_SYMBOL(stdin); 175 #endif 176 #ifndef stdout 177 EXPLICIT_SYMBOL(stdout); 178 #endif 179 #ifndef stderr 180 EXPLICIT_SYMBOL(stderr); 181 #endif 182 } 183 #endif 184 #undef EXPLICIT_SYMBOL 185 186 return 0; 187 } 188 189 #endif // LLVM_ON_WIN32 190
