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