lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp

   1 //===-- RuntimeDyldMachO.cpp - Run-time dynamic linker for MC-JIT -*- 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 // Implementation of the MC-JIT runtime dynamic linker.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "RuntimeDyldMachO.h"
  15 #include "Targets/RuntimeDyldMachOAArch64.h"
  16 #include "Targets/RuntimeDyldMachOARM.h"
  17 #include "Targets/RuntimeDyldMachOI386.h"
  18 #include "Targets/RuntimeDyldMachOX86_64.h"
  19 #include "llvm/ADT/STLExtras.h"
  20 #include "llvm/ADT/StringRef.h"
  21
  22 using namespace llvm;
  23 using namespace llvm::object;
  24
  25 #define DEBUG_TYPE "dyld"
  26
  27 namespace {
  28
  29 class LoadedMachOObjectInfo
  30     : public RuntimeDyld::LoadedObjectInfoHelper<LoadedMachOObjectInfo> {
  31 public:
  32   LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
  33                         ObjSectionToIDMap ObjSecToIDMap)
  34       : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
  35
  36   OwningBinary<ObjectFile>
  37   getObjectForDebug(const ObjectFile &Obj) const override {
  38     return OwningBinary<ObjectFile>();
  39   }
  40 };
  41
  42 }
  43
  44 namespace llvm {
  45
  46 int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
  47   unsigned NumBytes = 1 << RE.Size;
  48   uint8_t *Src = Sections[RE.SectionID].Address + RE.Offset;
  49
  50   return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
  51 }
  52
  53 relocation_iterator RuntimeDyldMachO::processScatteredVANILLA(
  54                           unsigned SectionID, relocation_iterator RelI,
  55                           const ObjectFile &BaseObjT,
  56                           RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID) {
  57   const MachOObjectFile &Obj =
  58     static_cast<const MachOObjectFile&>(BaseObjT);
  59   MachO::any_relocation_info RE =
  60     Obj.getRelocation(RelI->getRawDataRefImpl());
  61
  62   SectionEntry &Section = Sections[SectionID];
  63   uint32_t RelocType = Obj.getAnyRelocationType(RE);
  64   bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
  65   unsigned Size = Obj.getAnyRelocationLength(RE);
  66   uint64_t Offset = RelI->getOffset();
  67   uint8_t *LocalAddress = Section.Address + Offset;
  68   unsigned NumBytes = 1 << Size;
  69   int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
  70
  71   unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
  72   section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
  73   assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
  74   uint64_t SectionBaseAddr = TargetSI->getAddress();
  75   SectionRef TargetSection = *TargetSI;
  76   bool IsCode = TargetSection.isText();
  77   uint32_t TargetSectionID =
  78     findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID);
  79
  80   Addend -= SectionBaseAddr;
  81   RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
  82
  83   addRelocationForSection(R, TargetSectionID);
  84
  85   return ++RelI;
  86 }
  87
  88
  89 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
  90     const ObjectFile &BaseTObj, const relocation_iterator &RI,
  91     const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
  92
  93   const MachOObjectFile &Obj =
  94       static_cast<const MachOObjectFile &>(BaseTObj);
  95   MachO::any_relocation_info RelInfo =
  96       Obj.getRelocation(RI->getRawDataRefImpl());
  97   RelocationValueRef Value;
  98
  99   bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
 100   if (IsExternal) {
 101     symbol_iterator Symbol = RI->getSymbol();
 102     ErrorOr<StringRef> TargetNameOrErr = Symbol->getName();
 103     if (std::error_code EC = TargetNameOrErr.getError())
 104       report_fatal_error(EC.message());
 105     StringRef TargetName = *TargetNameOrErr;
 106     RTDyldSymbolTable::const_iterator SI =
 107       GlobalSymbolTable.find(TargetName.data());
 108     if (SI != GlobalSymbolTable.end()) {
 109       const auto &SymInfo = SI->second;
 110       Value.SectionID = SymInfo.getSectionID();
 111       Value.Offset = SymInfo.getOffset() + RE.Addend;
 112     } else {
 113       Value.SymbolName = TargetName.data();
 114       Value.Offset = RE.Addend;
 115     }
 116   } else {
 117     SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
 118     bool IsCode = Sec.isText();
 119     Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
 120     uint64_t Addr = Sec.getAddress();
 121     Value.Offset = RE.Addend - Addr;
 122   }
 123
 124   return Value;
 125 }
 126
 127 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
 128                                             const relocation_iterator &RI,
 129                                             unsigned OffsetToNextPC) {
 130   auto &O = *cast<MachOObjectFile>(RI->getObject());
 131   section_iterator SecI = O.getRelocationRelocatedSection(RI);
 132   Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
 133 }
 134
 135 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
 136                                                uint64_t Value) const {
 137   const SectionEntry &Section = Sections[RE.SectionID];
 138   uint8_t *LocalAddress = Section.Address + RE.Offset;
 139   uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
 140
 141   dbgs() << "resolveRelocation Section: " << RE.SectionID
 142          << " LocalAddress: " << format("%p", LocalAddress)
 143          << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
 144          << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
 145          << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
 146          << " Size: " << (1 << RE.Size) << "\n";
 147 }
 148
 149 section_iterator
 150 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
 151                                       uint64_t Addr) {
 152   section_iterator SI = Obj.section_begin();
 153   section_iterator SE = Obj.section_end();
 154
 155   for (; SI != SE; ++SI) {
 156     uint64_t SAddr = SI->getAddress();
 157     uint64_t SSize = SI->getSize();
 158     if ((Addr >= SAddr) && (Addr < SAddr + SSize))
 159       return SI;
 160   }
 161
 162   return SE;
 163 }
 164
 165
 166 // Populate __pointers section.
 167 void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
 168                                                     const MachOObjectFile &Obj,
 169                                                     const SectionRef &PTSection,
 170                                                     unsigned PTSectionID) {
 171   assert(!Obj.is64Bit() &&
 172          "Pointer table section not supported in 64-bit MachO.");
 173
 174   MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
 175   MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
 176   uint32_t PTSectionSize = Sec32.size;
 177   unsigned FirstIndirectSymbol = Sec32.reserved1;
 178   const unsigned PTEntrySize = 4;
 179   unsigned NumPTEntries = PTSectionSize / PTEntrySize;
 180   unsigned PTEntryOffset = 0;
 181
 182   assert((PTSectionSize % PTEntrySize) == 0 &&
 183          "Pointers section does not contain a whole number of stubs?");
 184
 185   DEBUG(dbgs() << "Populating pointer table section "
 186                << Sections[PTSectionID].Name
 187                << ", Section ID " << PTSectionID << ", "
 188                << NumPTEntries << " entries, " << PTEntrySize
 189                << " bytes each:\n");
 190
 191   for (unsigned i = 0; i < NumPTEntries; ++i) {
 192     unsigned SymbolIndex =
 193       Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
 194     symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
 195     ErrorOr<StringRef> IndirectSymbolNameOrErr = SI->getName();
 196     if (std::error_code EC = IndirectSymbolNameOrErr.getError())
 197       report_fatal_error(EC.message());
 198     StringRef IndirectSymbolName = *IndirectSymbolNameOrErr;
 199     DEBUG(dbgs() << "  " << IndirectSymbolName << ": index " << SymbolIndex
 200           << ", PT offset: " << PTEntryOffset << "\n");
 201     RelocationEntry RE(PTSectionID, PTEntryOffset,
 202                        MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
 203     addRelocationForSymbol(RE, IndirectSymbolName);
 204     PTEntryOffset += PTEntrySize;
 205   }
 206 }
 207
 208 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
 209   return Obj.isMachO();
 210 }
 211
 212 template <typename Impl>
 213 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
 214                                                   ObjSectionToIDMap &SectionMap) {
 215   unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
 216   unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
 217   unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
 218
 219   for (const auto &Section : Obj.sections()) {
 220     StringRef Name;
 221     Section.getName(Name);
 222
 223     // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
 224     // if they're present. Otherwise call down to the impl to handle other
 225     // sections that have already been emitted.
 226     if (Name == "__text")
 227       TextSID = findOrEmitSection(Obj, Section, true, SectionMap);
 228     else if (Name == "__eh_frame")
 229       EHFrameSID = findOrEmitSection(Obj, Section, false, SectionMap);
 230     else if (Name == "__gcc_except_tab")
 231       ExceptTabSID = findOrEmitSection(Obj, Section, true, SectionMap);
 232     else {
 233       auto I = SectionMap.find(Section);
 234       if (I != SectionMap.end())
 235         impl().finalizeSection(Obj, I->second, Section);
 236     }
 237   }
 238   UnregisteredEHFrameSections.push_back(
 239     EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
 240 }
 241
 242 template <typename Impl>
 243 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
 244                                                           int64_t DeltaForText,
 245                                                           int64_t DeltaForEH) {
 246   typedef typename Impl::TargetPtrT TargetPtrT;
 247
 248   DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
 249                << ", Delta for EH: " << DeltaForEH << "\n");
 250   uint32_t Length = readBytesUnaligned(P, 4);
 251   P += 4;
 252   unsigned char *Ret = P + Length;
 253   uint32_t Offset = readBytesUnaligned(P, 4);
 254   if (Offset == 0) // is a CIE
 255     return Ret;
 256
 257   P += 4;
 258   TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
 259   TargetPtrT NewLocation = FDELocation - DeltaForText;
 260   writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
 261
 262   P += sizeof(TargetPtrT);
 263
 264   // Skip the FDE address range
 265   P += sizeof(TargetPtrT);
 266
 267   uint8_t Augmentationsize = *P;
 268   P += 1;
 269   if (Augmentationsize != 0) {
 270     TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
 271     TargetPtrT NewLSDA = LSDA - DeltaForEH;
 272     writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
 273   }
 274
 275   return Ret;
 276 }
 277
 278 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
 279   int64_t ObjDistance =
 280     static_cast<int64_t>(A->ObjAddress) - static_cast<int64_t>(B->ObjAddress);
 281   int64_t MemDistance = A->LoadAddress - B->LoadAddress;
 282   return ObjDistance - MemDistance;
 283 }
 284
 285 template <typename Impl>
 286 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
 287
 288   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 289     EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
 290     if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
 291         SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
 292       continue;
 293     SectionEntry *Text = &Sections[SectionInfo.TextSID];
 294     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
 295     SectionEntry *ExceptTab = nullptr;
 296     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
 297       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 298
 299     int64_t DeltaForText = computeDelta(Text, EHFrame);
 300     int64_t DeltaForEH = 0;
 301     if (ExceptTab)
 302       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 303
 304     unsigned char *P = EHFrame->Address;
 305     unsigned char *End = P + EHFrame->Size;
 306     do {
 307       P = processFDE(P, DeltaForText, DeltaForEH);
 308     } while (P != End);
 309
 310     MemMgr.registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
 311                             EHFrame->Size);
 312   }
 313   UnregisteredEHFrameSections.clear();
 314 }
 315
 316 std::unique_ptr<RuntimeDyldMachO>
 317 RuntimeDyldMachO::create(Triple::ArchType Arch,
 318                          RuntimeDyld::MemoryManager &MemMgr,
 319                          RuntimeDyld::SymbolResolver &Resolver) {
 320   switch (Arch) {
 321   default:
 322     llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
 323     break;
 324   case Triple::arm:
 325     return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
 326   case Triple::aarch64:
 327     return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
 328   case Triple::x86:
 329     return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
 330   case Triple::x86_64:
 331     return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
 332   }
 333 }
 334
 335 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
 336 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
 337   return llvm::make_unique<LoadedMachOObjectInfo>(*this, loadObjectImpl(O));
 338 }
 339
 340 } // end namespace llvm