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