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