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 "llvm/ADT/STLExtras.h"
  16 #include "llvm/ADT/StringRef.h"
  17
  18 #include "Targets/RuntimeDyldMachOARM.h"
  19 #include "Targets/RuntimeDyldMachOAArch64.h"
  20 #include "Targets/RuntimeDyldMachOI386.h"
  21 #include "Targets/RuntimeDyldMachOX86_64.h"
  22
  23 using namespace llvm;
  24 using namespace llvm::object;
  25
  26 #define DEBUG_TYPE "dyld"
  27
  28 namespace {
  29
  30 class LoadedMachOObjectInfo : public RuntimeDyld::LoadedObjectInfo {
  31 public:
  32   LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
  33                         unsigned EndIdx)
  34     : RuntimeDyld::LoadedObjectInfo(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     StringRef TargetName;
  67     Symbol->getName(TargetName);
  68     SymbolTableMap::const_iterator SI =
  69       GlobalSymbolTable.find(TargetName.data());
  70     if (SI != GlobalSymbolTable.end()) {
  71       Value.SectionID = SI->second.first;
  72       Value.Offset = SI->second.second + RE.Addend;
  73     } else {
  74       Value.SymbolName = TargetName.data();
  75       Value.Offset = RE.Addend;
  76     }
  77   } else {
  78     SectionRef Sec = Obj.getRelocationSection(RelInfo);
  79     bool IsCode = Sec.isText();
  80     Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
  81     uint64_t Addr = Sec.getAddress();
  82     Value.Offset = RE.Addend - Addr;
  83   }
  84
  85   return Value;
  86 }
  87
  88 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
  89                                             const ObjectFile &BaseTObj,
  90                                             const relocation_iterator &RI,
  91                                             unsigned OffsetToNextPC) {
  92   const MachOObjectFile &Obj =
  93       static_cast<const MachOObjectFile &>(BaseTObj);
  94   MachO::any_relocation_info RelInfo =
  95       Obj.getRelocation(RI->getRawDataRefImpl());
  96
  97   bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
  98   if (IsPCRel) {
  99     uint64_t RelocAddr = 0;
 100     RI->getAddress(RelocAddr);
 101     Value.Offset += RelocAddr + OffsetToNextPC;
 102   }
 103 }
 104
 105 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
 106                                                uint64_t Value) const {
 107   const SectionEntry &Section = Sections[RE.SectionID];
 108   uint8_t *LocalAddress = Section.Address + RE.Offset;
 109   uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
 110
 111   dbgs() << "resolveRelocation Section: " << RE.SectionID
 112          << " LocalAddress: " << format("%p", LocalAddress)
 113          << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
 114          << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
 115          << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
 116          << " Size: " << (1 << RE.Size) << "\n";
 117 }
 118
 119 section_iterator
 120 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
 121                                       uint64_t Addr) {
 122   section_iterator SI = Obj.section_begin();
 123   section_iterator SE = Obj.section_end();
 124
 125   for (; SI != SE; ++SI) {
 126     uint64_t SAddr = SI->getAddress();
 127     uint64_t SSize = SI->getSize();
 128     if ((Addr >= SAddr) && (Addr < SAddr + SSize))
 129       return SI;
 130   }
 131
 132   return SE;
 133 }
 134
 135
 136 // Populate __pointers section.
 137 void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
 138                                                     const MachOObjectFile &Obj,
 139                                                     const SectionRef &PTSection,
 140                                                     unsigned PTSectionID) {
 141   assert(!Obj.is64Bit() &&
 142          "Pointer table section not supported in 64-bit MachO.");
 143
 144   MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
 145   MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
 146   uint32_t PTSectionSize = Sec32.size;
 147   unsigned FirstIndirectSymbol = Sec32.reserved1;
 148   const unsigned PTEntrySize = 4;
 149   unsigned NumPTEntries = PTSectionSize / PTEntrySize;
 150   unsigned PTEntryOffset = 0;
 151
 152   assert((PTSectionSize % PTEntrySize) == 0 &&
 153          "Pointers section does not contain a whole number of stubs?");
 154
 155   DEBUG(dbgs() << "Populating pointer table section "
 156                << Sections[PTSectionID].Name
 157                << ", Section ID " << PTSectionID << ", "
 158                << NumPTEntries << " entries, " << PTEntrySize
 159                << " bytes each:\n");
 160
 161   for (unsigned i = 0; i < NumPTEntries; ++i) {
 162     unsigned SymbolIndex =
 163       Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
 164     symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
 165     StringRef IndirectSymbolName;
 166     SI->getName(IndirectSymbolName);
 167     DEBUG(dbgs() << "  " << IndirectSymbolName << ": index " << SymbolIndex
 168           << ", PT offset: " << PTEntryOffset << "\n");
 169     RelocationEntry RE(PTSectionID, PTEntryOffset,
 170                        MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
 171     addRelocationForSymbol(RE, IndirectSymbolName);
 172     PTEntryOffset += PTEntrySize;
 173   }
 174 }
 175
 176 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
 177   return Obj.isMachO();
 178 }
 179
 180 template <typename Impl>
 181 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &ObjImg,
 182                                                   ObjSectionToIDMap &SectionMap) {
 183   unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
 184   unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
 185   unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
 186   ObjSectionToIDMap::iterator i, e;
 187
 188   for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
 189     const SectionRef &Section = i->first;
 190     StringRef Name;
 191     Section.getName(Name);
 192     if (Name == "__eh_frame")
 193       EHFrameSID = i->second;
 194     else if (Name == "__text")
 195       TextSID = i->second;
 196     else if (Name == "__gcc_except_tab")
 197       ExceptTabSID = i->second;
 198     else
 199       impl().finalizeSection(ObjImg, i->second, Section);
 200   }
 201   UnregisteredEHFrameSections.push_back(
 202     EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
 203 }
 204
 205 template <typename Impl>
 206 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
 207                                                           int64_t DeltaForText,
 208                                                           int64_t DeltaForEH) {
 209   typedef typename Impl::TargetPtrT TargetPtrT;
 210
 211   DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
 212                << ", Delta for EH: " << DeltaForEH << "\n");
 213   uint32_t Length = readBytesUnaligned(P, 4);
 214   P += 4;
 215   unsigned char *Ret = P + Length;
 216   uint32_t Offset = readBytesUnaligned(P, 4);
 217   if (Offset == 0) // is a CIE
 218     return Ret;
 219
 220   P += 4;
 221   TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
 222   TargetPtrT NewLocation = FDELocation - DeltaForText;
 223   writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
 224
 225   P += sizeof(TargetPtrT);
 226
 227   // Skip the FDE address range
 228   P += sizeof(TargetPtrT);
 229
 230   uint8_t Augmentationsize = *P;
 231   P += 1;
 232   if (Augmentationsize != 0) {
 233     TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
 234     TargetPtrT NewLSDA = LSDA - DeltaForEH;
 235     writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
 236   }
 237
 238   return Ret;
 239 }
 240
 241 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
 242   int64_t ObjDistance = A->ObjAddress - B->ObjAddress;
 243   int64_t MemDistance = A->LoadAddress - B->LoadAddress;
 244   return ObjDistance - MemDistance;
 245 }
 246
 247 template <typename Impl>
 248 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
 249
 250   if (!MemMgr)
 251     return;
 252   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 253     EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
 254     if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
 255         SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
 256       continue;
 257     SectionEntry *Text = &Sections[SectionInfo.TextSID];
 258     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
 259     SectionEntry *ExceptTab = nullptr;
 260     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
 261       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 262
 263     int64_t DeltaForText = computeDelta(Text, EHFrame);
 264     int64_t DeltaForEH = 0;
 265     if (ExceptTab)
 266       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 267
 268     unsigned char *P = EHFrame->Address;
 269     unsigned char *End = P + EHFrame->Size;
 270     do {
 271       P = processFDE(P, DeltaForText, DeltaForEH);
 272     } while (P != End);
 273
 274     MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
 275                              EHFrame->Size);
 276   }
 277   UnregisteredEHFrameSections.clear();
 278 }
 279
 280 std::unique_ptr<RuntimeDyldMachO>
 281 RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
 282   switch (Arch) {
 283   default:
 284     llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
 285     break;
 286   case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
 287   case Triple::aarch64: return make_unique<RuntimeDyldMachOAArch64>(MM);
 288   case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
 289   case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
 290   }
 291 }
 292
 293 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
 294 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
 295   unsigned SectionStartIdx, SectionEndIdx;
 296   std::tie(SectionStartIdx, SectionEndIdx) = loadObjectImpl(O);
 297   return llvm::make_unique<LoadedMachOObjectInfo>(*this, SectionStartIdx,
 298                                                   SectionEndIdx);
 299 }
 300
 301 } // end namespace llvm