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 llvm {
  29
  30 int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
  31   const SectionEntry &Section = Sections[RE.SectionID];
  32   uint8_t *LocalAddress = Section.Address + RE.Offset;
  33   unsigned NumBytes = 1 << RE.Size;
  34   int64_t Addend = 0;
  35   memcpy(&Addend, LocalAddress, NumBytes);
  36   return Addend;
  37 }
  38
  39 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
  40     ObjectImage &ObjImg, const relocation_iterator &RI,
  41     const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID,
  42     const SymbolTableMap &Symbols) {
  43
  44   const MachOObjectFile &Obj =
  45       static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
  46   MachO::any_relocation_info RelInfo =
  47       Obj.getRelocation(RI->getRawDataRefImpl());
  48   RelocationValueRef Value;
  49
  50   bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
  51   if (IsExternal) {
  52     symbol_iterator Symbol = RI->getSymbol();
  53     StringRef TargetName;
  54     Symbol->getName(TargetName);
  55     SymbolTableMap::const_iterator SI = Symbols.find(TargetName.data());
  56     if (SI != Symbols.end()) {
  57       Value.SectionID = SI->second.first;
  58       Value.Addend = SI->second.second + RE.Addend;
  59     } else {
  60       SI = GlobalSymbolTable.find(TargetName.data());
  61       if (SI != GlobalSymbolTable.end()) {
  62         Value.SectionID = SI->second.first;
  63         Value.Addend = SI->second.second + RE.Addend;
  64       } else {
  65         Value.SymbolName = TargetName.data();
  66         Value.Addend = RE.Addend;
  67       }
  68     }
  69   } else {
  70     SectionRef Sec = Obj.getRelocationSection(RelInfo);
  71     bool IsCode = false;
  72     Sec.isText(IsCode);
  73     Value.SectionID = findOrEmitSection(ObjImg, Sec, IsCode, ObjSectionToID);
  74     uint64_t Addr;
  75     Sec.getAddress(Addr);
  76     Value.Addend = RE.Addend - Addr;
  77   }
  78
  79   return Value;
  80 }
  81
  82 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
  83                                             ObjectImage &ObjImg,
  84                                             const relocation_iterator &RI,
  85                                             unsigned OffsetToNextPC) {
  86   const MachOObjectFile &Obj =
  87       static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
  88   MachO::any_relocation_info RelInfo =
  89       Obj.getRelocation(RI->getRawDataRefImpl());
  90
  91   bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
  92   if (IsPCRel) {
  93     uint64_t RelocAddr = 0;
  94     RI->getAddress(RelocAddr);
  95     Value.Addend += RelocAddr + OffsetToNextPC;
  96   }
  97 }
  98
  99 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
 100                                                uint64_t Value) const {
 101   const SectionEntry &Section = Sections[RE.SectionID];
 102   uint8_t *LocalAddress = Section.Address + RE.Offset;
 103   uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
 104
 105   dbgs() << "resolveRelocation Section: " << RE.SectionID
 106          << " LocalAddress: " << format("%p", LocalAddress)
 107          << " FinalAddress: " << format("%p", FinalAddress)
 108          << " Value: " << format("%p", Value) << " Addend: " << RE.Addend
 109          << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
 110          << " Size: " << (1 << RE.Size) << "\n";
 111 }
 112
 113 bool RuntimeDyldMachO::writeBytesUnaligned(uint8_t *Addr, uint64_t Value,
 114                                            unsigned Size) {
 115   for (unsigned i = 0; i < Size; ++i) {
 116     *Addr++ = (uint8_t)Value;
 117     Value >>= 8;
 118   }
 119
 120   return false;
 121 }
 122
 123 bool
 124 RuntimeDyldMachO::isCompatibleFormat(const ObjectBuffer *InputBuffer) const {
 125   if (InputBuffer->getBufferSize() < 4)
 126     return false;
 127   StringRef Magic(InputBuffer->getBufferStart(), 4);
 128   if (Magic == "\xFE\xED\xFA\xCE")
 129     return true;
 130   if (Magic == "\xCE\xFA\xED\xFE")
 131     return true;
 132   if (Magic == "\xFE\xED\xFA\xCF")
 133     return true;
 134   if (Magic == "\xCF\xFA\xED\xFE")
 135     return true;
 136   return false;
 137 }
 138
 139 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile *Obj) const {
 140   return Obj->isMachO();
 141 }
 142
 143 static unsigned char *processFDE(unsigned char *P, intptr_t DeltaForText,
 144                                  intptr_t DeltaForEH) {
 145   DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
 146                << ", Delta for EH: " << DeltaForEH << "\n");
 147   uint32_t Length = *((uint32_t *)P);
 148   P += 4;
 149   unsigned char *Ret = P + Length;
 150   uint32_t Offset = *((uint32_t *)P);
 151   if (Offset == 0) // is a CIE
 152     return Ret;
 153
 154   P += 4;
 155   intptr_t FDELocation = *((intptr_t *)P);
 156   intptr_t NewLocation = FDELocation - DeltaForText;
 157   *((intptr_t *)P) = NewLocation;
 158   P += sizeof(intptr_t);
 159
 160   // Skip the FDE address range
 161   P += sizeof(intptr_t);
 162
 163   uint8_t Augmentationsize = *P;
 164   P += 1;
 165   if (Augmentationsize != 0) {
 166     intptr_t LSDA = *((intptr_t *)P);
 167     intptr_t NewLSDA = LSDA - DeltaForEH;
 168     *((intptr_t *)P) = NewLSDA;
 169   }
 170
 171   return Ret;
 172 }
 173
 174 static intptr_t computeDelta(SectionEntry *A, SectionEntry *B) {
 175   intptr_t ObjDistance = A->ObjAddress - B->ObjAddress;
 176   intptr_t MemDistance = A->LoadAddress - B->LoadAddress;
 177   return ObjDistance - MemDistance;
 178 }
 179
 180 void RuntimeDyldMachO::registerEHFrames() {
 181
 182   if (!MemMgr)
 183     return;
 184   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 185     EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
 186     if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
 187         SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
 188       continue;
 189     SectionEntry *Text = &Sections[SectionInfo.TextSID];
 190     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
 191     SectionEntry *ExceptTab = nullptr;
 192     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
 193       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 194
 195     intptr_t DeltaForText = computeDelta(Text, EHFrame);
 196     intptr_t DeltaForEH = 0;
 197     if (ExceptTab)
 198       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 199
 200     unsigned char *P = EHFrame->Address;
 201     unsigned char *End = P + EHFrame->Size;
 202     do {
 203       P = processFDE(P, DeltaForText, DeltaForEH);
 204     } while (P != End);
 205
 206     MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
 207                              EHFrame->Size);
 208   }
 209   UnregisteredEHFrameSections.clear();
 210 }
 211
 212 std::unique_ptr<RuntimeDyldMachO>
 213 llvm::RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
 214   switch (Arch) {
 215   default:
 216     llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
 217     break;
 218   case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
 219   case Triple::aarch64: return make_unique<RuntimeDyldMachOAArch64>(MM);
 220   case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
 221   case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
 222   }
 223 }
 224
 225 } // end namespace llvm