1 //===-- DynamicLibrary.cpp - Runtime link/load libraries --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This header file implements the operating system DynamicLibrary concept.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/System/DynamicLibrary.h"
15 #include "llvm/Support/ManagedStatic.h"
16 #include "llvm/System/RWMutex.h"
17 #include "llvm/Config/config.h"
22 // Collection of symbol name/value pairs to be searched prior to any libraries.
23 static std::map<std::string, void*> symbols;
24 static llvm::sys::SmartRWMutex<true> SymbolsLock;
27 void llvm::sys::DynamicLibrary::AddSymbol(const char* symbolName,
29 llvm::sys::SmartScopedWriter<true> Writer(&SymbolsLock);
30 symbols[symbolName] = symbolValue;
33 // It is not possible to use ltdl.c on VC++ builds as the terms of its LGPL
34 // license and special exception would cause all of LLVM to be placed under
35 // the LGPL. This is because the exception applies only when libtool is
36 // used, and obviously libtool is not used with Visual Studio. An entirely
37 // separate implementation is provided in win32/DynamicLibrary.cpp.
41 #include "Win32/DynamicLibrary.inc"
49 using namespace llvm::sys;
51 //===----------------------------------------------------------------------===//
52 //=== WARNING: Implementation here must contain only TRULY operating system
53 //=== independent code.
54 //===----------------------------------------------------------------------===//
56 //static std::vector<lt_dlhandle> OpenedHandles;
57 static std::vector<void *> OpenedHandles;
59 DynamicLibrary::DynamicLibrary() {}
61 DynamicLibrary::~DynamicLibrary() {
62 SmartScopedWriter<true> Writer(&SymbolsLock);
63 while(!OpenedHandles.empty()) {
64 void *H = OpenedHandles.back(); OpenedHandles.pop_back();
69 bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
70 std::string *ErrMsg) {
71 SmartScopedWriter<true> Writer(&SymbolsLock);
72 void *H = dlopen(Filename, RTLD_LAZY|RTLD_GLOBAL);
78 OpenedHandles.push_back(H);
82 void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
83 // check_ltdl_initialization();
85 // First check symbols added via AddSymbol().
86 SymbolsLock.reader_acquire();
87 std::map<std::string, void *>::iterator I = symbols.find(symbolName);
88 std::map<std::string, void *>::iterator E = symbols.end();
89 SymbolsLock.reader_release();
94 SymbolsLock.writer_acquire();
95 // Now search the libraries.
96 for (std::vector<void *>::iterator I = OpenedHandles.begin(),
97 E = OpenedHandles.end(); I != E; ++I) {
98 //lt_ptr ptr = lt_dlsym(*I, symbolName);
99 void *ptr = dlsym(*I, symbolName);
101 SymbolsLock.writer_release();
105 SymbolsLock.writer_release();
107 #define EXPLICIT_SYMBOL(SYM) \
108 extern void *SYM; if (!strcmp(symbolName, #SYM)) return &SYM
110 // If this is darwin, it has some funky issues, try to solve them here. Some
111 // important symbols are marked 'private external' which doesn't allow
112 // SearchForAddressOfSymbol to find them. As such, we special case them here,
113 // there is only a small handful of them.
117 EXPLICIT_SYMBOL(__ashldi3);
118 EXPLICIT_SYMBOL(__ashrdi3);
119 EXPLICIT_SYMBOL(__cmpdi2);
120 EXPLICIT_SYMBOL(__divdi3);
121 EXPLICIT_SYMBOL(__eprintf);
122 EXPLICIT_SYMBOL(__fixdfdi);
123 EXPLICIT_SYMBOL(__fixsfdi);
124 EXPLICIT_SYMBOL(__fixunsdfdi);
125 EXPLICIT_SYMBOL(__fixunssfdi);
126 EXPLICIT_SYMBOL(__floatdidf);
127 EXPLICIT_SYMBOL(__floatdisf);
128 EXPLICIT_SYMBOL(__lshrdi3);
129 EXPLICIT_SYMBOL(__moddi3);
130 EXPLICIT_SYMBOL(__udivdi3);
131 EXPLICIT_SYMBOL(__umoddi3);
137 EXPLICIT_SYMBOL(_alloca);
138 EXPLICIT_SYMBOL(__main);
142 #undef EXPLICIT_SYMBOL
144 // This macro returns the address of a well-known, explicit symbol
145 #define EXPLICIT_SYMBOL(SYM) \
146 if (!strcmp(symbolName, #SYM)) return &SYM
148 // On linux we have a weird situation. The stderr/out/in symbols are both
149 // macros and global variables because of standards requirements. So, we
150 // boldly use the EXPLICIT_SYMBOL macro without checking for a #define first.
151 #if defined(__linux__)
153 EXPLICIT_SYMBOL(stderr);
154 EXPLICIT_SYMBOL(stdout);
155 EXPLICIT_SYMBOL(stdin);
158 // For everything else, we want to check to make sure the symbol isn't defined
159 // as a macro before using EXPLICIT_SYMBOL.
162 EXPLICIT_SYMBOL(stdin);
165 EXPLICIT_SYMBOL(stdout);
168 EXPLICIT_SYMBOL(stderr);
172 #undef EXPLICIT_SYMBOL
177 #endif // LLVM_ON_WIN32