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 {
~ExplicitSymbolsDeleter__anon6e3a38a30111::ExplicitSymbolsDeleter30 ~ExplicitSymbolsDeleter() {
31 delete ExplicitSymbols;
32 }
33 };
34
35 }
36
37 static ExplicitSymbolsDeleter Dummy;
38
39
getMutex()40 static llvm::sys::SmartMutex<true>& getMutex() {
41 static llvm::sys::SmartMutex<true> HandlesMutex;
42 return HandlesMutex;
43 }
44
AddSymbol(StringRef symbolName,void * symbolValue)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
getPermanentLibrary(const char * filename,std::string * errMsg)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
getAddressOfSymbol(const char * symbolName)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
getPermanentLibrary(const char * filename,std::string * errMsg)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
getAddressOfSymbol(const char * symbolName)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
SearchForAddressOfSymbol(const char * symbolName)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