llvm/lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp

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