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. 25static llvm::StringMap<void *> *ExplicitSymbols = 0; 26 27namespace { 28 29struct ExplicitSymbolsDeleter { 30 ~ExplicitSymbolsDeleter() { 31 delete ExplicitSymbols; 32 } 33}; 34 35} 36 37static ExplicitSymbolsDeleter Dummy; 38 39 40static llvm::sys::SmartMutex<true>& getMutex() { 41 static llvm::sys::SmartMutex<true> HandlesMutex; 42 return HandlesMutex; 43} 44 45void 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 53char 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> 63using namespace llvm; 64using namespace llvm::sys; 65 66//===----------------------------------------------------------------------===// 67//=== WARNING: Implementation here must contain only TRULY operating system 68//=== independent code. 69//===----------------------------------------------------------------------===// 70 71static DenseSet<void *> *OpenedHandles = 0; 72 73DynamicLibrary 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 101void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) { 102 if (!isValid()) 103 return NULL; 104 return dlsym(Data, symbolName); 105} 106 107#else 108 109using namespace llvm; 110using namespace llvm::sys; 111 112DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename, 113 std::string *errMsg) { 114 if (errMsg) *errMsg = "dlopen() not supported on this platform"; 115 return DynamicLibrary(); 116} 117 118void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) { 119 return NULL; 120} 121 122#endif 123 124namespace llvm { 125void *SearchForAddressOfSpecialSymbol(const char* symbolName); 126} 127 128void* 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