1 //===-- RTDyldMemoryManager.cpp - Memory manager for MC-JIT -----*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Implementation of the runtime dynamic memory manager base class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/Config/config.h" 14 #include "llvm/ExecutionEngine/RTDyldMemoryManager.h" 15 #include "llvm/Support/Compiler.h" 16 #include "llvm/Support/DynamicLibrary.h" 17 #include "llvm/Support/ErrorHandling.h" 18 #include <cstdlib> 19 20 #ifdef __linux__ 21 // These includes used by RTDyldMemoryManager::getPointerToNamedFunction() 22 // for Glibc trickery. See comments in this function for more information. 23 #include <fcntl.h> 24 #include <sys/stat.h> 25 #include <unistd.h> 26 #endif 27 28 namespace llvm { 29 30 RTDyldMemoryManager::~RTDyldMemoryManager() = default; 31 32 #if defined(HAVE_REGISTER_FRAME) && defined(HAVE_DEREGISTER_FRAME) && \ 33 !defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__) 34 extern "C" void __register_frame(void *); 35 extern "C" void __deregister_frame(void *); 36 #else 37 // The building compiler does not have __(de)register_frame but 38 // it may be found at runtime in a dynamically-loaded library. 39 // For example, this happens when building LLVM with Visual C++ 40 // but using the MingW runtime. 41 static void __register_frame(void *p) { 42 static bool Searched = false; 43 static void (*rf)(void *) = 0; 44 45 if (!Searched) { 46 Searched = true; 47 *(void **)&rf = 48 llvm::sys::DynamicLibrary::SearchForAddressOfSymbol("__register_frame"); 49 } 50 if (rf) 51 rf(p); 52 } 53 54 static void __deregister_frame(void *p) { 55 static bool Searched = false; 56 static void (*df)(void *) = 0; 57 58 if (!Searched) { 59 Searched = true; 60 *(void **)&df = llvm::sys::DynamicLibrary::SearchForAddressOfSymbol( 61 "__deregister_frame"); 62 } 63 if (df) 64 df(p); 65 } 66 #endif 67 68 /* libgcc and libunwind __register_frame behave differently. We use the presence 69 * of __unw_add_dynamic_fde to detect libunwind. */ 70 #if defined(HAVE_UNW_ADD_DYNAMIC_FDE) || defined(__APPLE__) 71 72 static const char *processFDE(const char *Entry, bool isDeregister) { 73 const char *P = Entry; 74 uint32_t Length = *((const uint32_t *)P); 75 P += 4; 76 uint32_t Offset = *((const uint32_t *)P); 77 if (Offset != 0) { 78 if (isDeregister) 79 __deregister_frame(const_cast<char *>(Entry)); 80 else 81 __register_frame(const_cast<char *>(Entry)); 82 } 83 return P + Length; 84 } 85 86 // This implementation handles frame registration for local targets. 87 // Memory managers for remote targets should re-implement this function 88 // and use the LoadAddr parameter. 89 void RTDyldMemoryManager::registerEHFramesInProcess(uint8_t *Addr, 90 size_t Size) { 91 // On OS X OS X __register_frame takes a single FDE as an argument. 92 // See http://lists.llvm.org/pipermail/llvm-dev/2013-April/061737.html 93 // and projects/libunwind/src/UnwindLevel1-gcc-ext.c. 94 const char *P = (const char *)Addr; 95 const char *End = P + Size; 96 while (P != End) 97 P = processFDE(P, false); 98 } 99 100 void RTDyldMemoryManager::deregisterEHFramesInProcess(uint8_t *Addr, 101 size_t Size) { 102 const char *P = (const char *)Addr; 103 const char *End = P + Size; 104 while (P != End) 105 P = processFDE(P, true); 106 } 107 108 #else 109 110 void RTDyldMemoryManager::registerEHFramesInProcess(uint8_t *Addr, 111 size_t Size) { 112 // On Linux __register_frame takes a single argument: 113 // a pointer to the start of the .eh_frame section. 114 115 // How can it find the end? Because crtendS.o is linked 116 // in and it has an .eh_frame section with four zero chars. 117 __register_frame(Addr); 118 } 119 120 void RTDyldMemoryManager::deregisterEHFramesInProcess(uint8_t *Addr, 121 size_t Size) { 122 __deregister_frame(Addr); 123 } 124 125 #endif 126 127 void RTDyldMemoryManager::registerEHFrames(uint8_t *Addr, uint64_t LoadAddr, 128 size_t Size) { 129 registerEHFramesInProcess(Addr, Size); 130 EHFrames.push_back({Addr, Size}); 131 } 132 133 void RTDyldMemoryManager::deregisterEHFrames() { 134 for (auto &Frame : EHFrames) 135 deregisterEHFramesInProcess(Frame.Addr, Frame.Size); 136 EHFrames.clear(); 137 } 138 139 static int jit_noop() { 140 return 0; 141 } 142 143 // ARM math functions are statically linked on Android from libgcc.a, but not 144 // available at runtime for dynamic linking. On Linux these are usually placed 145 // in libgcc_s.so so can be found by normal dynamic lookup. 146 #if defined(__BIONIC__) && defined(__arm__) 147 // List of functions which are statically linked on Android and can be generated 148 // by LLVM. This is done as a nested macro which is used once to declare the 149 // imported functions with ARM_MATH_DECL and once to compare them to the 150 // user-requested symbol in getSymbolAddress with ARM_MATH_CHECK. The test 151 // assumes that all functions start with __aeabi_ and getSymbolAddress must be 152 // modified if that changes. 153 #define ARM_MATH_IMPORTS(PP) \ 154 PP(__aeabi_d2f) \ 155 PP(__aeabi_d2iz) \ 156 PP(__aeabi_d2lz) \ 157 PP(__aeabi_d2uiz) \ 158 PP(__aeabi_d2ulz) \ 159 PP(__aeabi_dadd) \ 160 PP(__aeabi_dcmpeq) \ 161 PP(__aeabi_dcmpge) \ 162 PP(__aeabi_dcmpgt) \ 163 PP(__aeabi_dcmple) \ 164 PP(__aeabi_dcmplt) \ 165 PP(__aeabi_dcmpun) \ 166 PP(__aeabi_ddiv) \ 167 PP(__aeabi_dmul) \ 168 PP(__aeabi_dsub) \ 169 PP(__aeabi_f2d) \ 170 PP(__aeabi_f2iz) \ 171 PP(__aeabi_f2lz) \ 172 PP(__aeabi_f2uiz) \ 173 PP(__aeabi_f2ulz) \ 174 PP(__aeabi_fadd) \ 175 PP(__aeabi_fcmpeq) \ 176 PP(__aeabi_fcmpge) \ 177 PP(__aeabi_fcmpgt) \ 178 PP(__aeabi_fcmple) \ 179 PP(__aeabi_fcmplt) \ 180 PP(__aeabi_fcmpun) \ 181 PP(__aeabi_fdiv) \ 182 PP(__aeabi_fmul) \ 183 PP(__aeabi_fsub) \ 184 PP(__aeabi_i2d) \ 185 PP(__aeabi_i2f) \ 186 PP(__aeabi_idiv) \ 187 PP(__aeabi_idivmod) \ 188 PP(__aeabi_l2d) \ 189 PP(__aeabi_l2f) \ 190 PP(__aeabi_lasr) \ 191 PP(__aeabi_ldivmod) \ 192 PP(__aeabi_llsl) \ 193 PP(__aeabi_llsr) \ 194 PP(__aeabi_lmul) \ 195 PP(__aeabi_ui2d) \ 196 PP(__aeabi_ui2f) \ 197 PP(__aeabi_uidiv) \ 198 PP(__aeabi_uidivmod) \ 199 PP(__aeabi_ul2d) \ 200 PP(__aeabi_ul2f) \ 201 PP(__aeabi_uldivmod) 202 203 // Declare statically linked math functions on ARM. The function declarations 204 // here do not have the correct prototypes for each function in 205 // ARM_MATH_IMPORTS, but it doesn't matter because only the symbol addresses are 206 // needed. In particular the __aeabi_*divmod functions do not have calling 207 // conventions which match any C prototype. 208 #define ARM_MATH_DECL(name) extern "C" void name(); 209 ARM_MATH_IMPORTS(ARM_MATH_DECL) 210 #undef ARM_MATH_DECL 211 #endif 212 213 #if defined(__linux__) && defined(__GLIBC__) && \ 214 (defined(__i386__) || defined(__x86_64__)) 215 extern "C" LLVM_ATTRIBUTE_WEAK void __morestack(); 216 #endif 217 218 uint64_t 219 RTDyldMemoryManager::getSymbolAddressInProcess(const std::string &Name) { 220 // This implementation assumes that the host program is the target. 221 // Clients generating code for a remote target should implement their own 222 // memory manager. 223 #if defined(__linux__) && defined(__GLIBC__) 224 //===--------------------------------------------------------------------===// 225 // Function stubs that are invoked instead of certain library calls 226 // 227 // Force the following functions to be linked in to anything that uses the 228 // JIT. This is a hack designed to work around the all-too-clever Glibc 229 // strategy of making these functions work differently when inlined vs. when 230 // not inlined, and hiding their real definitions in a separate archive file 231 // that the dynamic linker can't see. For more info, search for 232 // 'libc_nonshared.a' on Google, or read http://llvm.org/PR274. 233 if (Name == "stat") return (uint64_t)&stat; 234 if (Name == "fstat") return (uint64_t)&fstat; 235 if (Name == "lstat") return (uint64_t)&lstat; 236 if (Name == "stat64") return (uint64_t)&stat64; 237 if (Name == "fstat64") return (uint64_t)&fstat64; 238 if (Name == "lstat64") return (uint64_t)&lstat64; 239 if (Name == "atexit") return (uint64_t)&atexit; 240 if (Name == "mknod") return (uint64_t)&mknod; 241 242 #if defined(__i386__) || defined(__x86_64__) 243 // __morestack lives in libgcc, a static library. 244 if (&__morestack && Name == "__morestack") 245 return (uint64_t)&__morestack; 246 #endif 247 #endif // __linux__ && __GLIBC__ 248 249 // See ARM_MATH_IMPORTS definition for explanation 250 #if defined(__BIONIC__) && defined(__arm__) 251 if (Name.compare(0, 8, "__aeabi_") == 0) { 252 // Check if the user has requested any of the functions listed in 253 // ARM_MATH_IMPORTS, and if so redirect to the statically linked symbol. 254 #define ARM_MATH_CHECK(fn) if (Name == #fn) return (uint64_t)&fn; 255 ARM_MATH_IMPORTS(ARM_MATH_CHECK) 256 #undef ARM_MATH_CHECK 257 } 258 #endif 259 260 // We should not invoke parent's ctors/dtors from generated main()! 261 // On Mingw and Cygwin, the symbol __main is resolved to 262 // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors 263 // (and register wrong callee's dtors with atexit(3)). 264 // We expect ExecutionEngine::runStaticConstructorsDestructors() 265 // is called before ExecutionEngine::runFunctionAsMain() is called. 266 if (Name == "__main") return (uint64_t)&jit_noop; 267 268 const char *NameStr = Name.c_str(); 269 270 // DynamicLibrary::SearchForAddressOfSymbol expects an unmangled 'C' symbol 271 // name so ff we're on Darwin, strip the leading '_' off. 272 #ifdef __APPLE__ 273 if (NameStr[0] == '_') 274 ++NameStr; 275 #endif 276 277 return (uint64_t)sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr); 278 } 279 280 void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name, 281 bool AbortOnFailure) { 282 uint64_t Addr = getSymbolAddress(Name); 283 284 if (!Addr && AbortOnFailure) 285 report_fatal_error(Twine("Program used external function '") + Name + 286 "' which could not be resolved!"); 287 288 return (void*)Addr; 289 } 290 291 void RTDyldMemoryManager::anchor() {} 292 void MCJITMemoryManager::anchor() {} 293 } // namespace llvm 294