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 uint64_t RuntimeDyldMachO::decodeAddend(uint8_t *LocalAddress, unsigned NumBytes,
  31                                         uint32_t RelType) const {
  32   uint64_t Addend = 0;
  33   memcpy(&Addend, LocalAddress, NumBytes);
  34   return Addend;
  35 }
  36
  37 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
  38     ObjectImage &ObjImg, const relocation_iterator &RI,
  39     const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID,
  40     const SymbolTableMap &Symbols) {
  41
  42   const MachOObjectFile &Obj =
  43       static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
  44   MachO::any_relocation_info RelInfo =
  45       Obj.getRelocation(RI->getRawDataRefImpl());
  46   RelocationValueRef Value;
  47
  48   bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
  49   if (IsExternal) {
  50     symbol_iterator Symbol = RI->getSymbol();
  51     StringRef TargetName;
  52     Symbol->getName(TargetName);
  53     SymbolTableMap::const_iterator SI = Symbols.find(TargetName.data());
  54     if (SI != Symbols.end()) {
  55       Value.SectionID = SI->second.first;
  56       Value.Addend = SI->second.second + RE.Addend;
  57     } else {
  58       SI = GlobalSymbolTable.find(TargetName.data());
  59       if (SI != GlobalSymbolTable.end()) {
  60         Value.SectionID = SI->second.first;
  61         Value.Addend = SI->second.second + RE.Addend;
  62       } else {
  63         Value.SymbolName = TargetName.data();
  64         Value.Addend = RE.Addend;
  65       }
  66     }
  67   } else {
  68     SectionRef Sec = Obj.getRelocationSection(RelInfo);
  69     bool IsCode = false;
  70     Sec.isText(IsCode);
  71     Value.SectionID = findOrEmitSection(ObjImg, Sec, IsCode, ObjSectionToID);
  72     uint64_t Addr;
  73     Sec.getAddress(Addr);
  74     Value.Addend = RE.Addend - Addr;
  75   }
  76
  77   return Value;
  78 }
  79
  80 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
  81                                             ObjectImage &ObjImg,
  82                                             const relocation_iterator &RI) {
  83   const MachOObjectFile &Obj =
  84       static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
  85   MachO::any_relocation_info RelInfo =
  86       Obj.getRelocation(RI->getRawDataRefImpl());
  87
  88   bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
  89   if (IsPCRel) {
  90     uint64_t RelocAddr = 0;
  91     RI->getAddress(RelocAddr);
  92     unsigned RelocSize = Obj.getAnyRelocationLength(RelInfo);
  93     Value.Addend += RelocAddr + (1ULL << RelocSize);
  94   }
  95 }
  96
  97 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
  98                                                uint64_t Value) const {
  99   const SectionEntry &Section = Sections[RE.SectionID];
 100   uint8_t *LocalAddress = Section.Address + RE.Offset;
 101   uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
 102
 103   dbgs() << "resolveRelocation Section: " << RE.SectionID
 104          << " LocalAddress: " << format("%p", LocalAddress)
 105          << " FinalAddress: " << format("%p", FinalAddress)
 106          << " Value: " << format("%p", Value) << " Addend: " << RE.Addend
 107          << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
 108          << " Size: " << (1 << RE.Size) << "\n";
 109 }
 110
 111 bool RuntimeDyldMachO::writeBytesUnaligned(uint8_t *Addr, uint64_t Value,
 112                                            unsigned Size) {
 113   for (unsigned i = 0; i < Size; ++i) {
 114     *Addr++ = (uint8_t)Value;
 115     Value >>= 8;
 116   }
 117
 118   return false;
 119 }
 120
 121 bool
 122 RuntimeDyldMachO::isCompatibleFormat(const ObjectBuffer *InputBuffer) const {
 123   if (InputBuffer->getBufferSize() < 4)
 124     return false;
 125   StringRef Magic(InputBuffer->getBufferStart(), 4);
 126   if (Magic == "\xFE\xED\xFA\xCE")
 127     return true;
 128   if (Magic == "\xCE\xFA\xED\xFE")
 129     return true;
 130   if (Magic == "\xFE\xED\xFA\xCF")
 131     return true;
 132   if (Magic == "\xCF\xFA\xED\xFE")
 133     return true;
 134   return false;
 135 }
 136
 137 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile *Obj) const {
 138   return Obj->isMachO();
 139 }
 140
 141 static unsigned char *processFDE(unsigned char *P, intptr_t DeltaForText,
 142                                  intptr_t DeltaForEH) {
 143   DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
 144                << ", Delta for EH: " << DeltaForEH << "\n");
 145   uint32_t Length = *((uint32_t *)P);
 146   P += 4;
 147   unsigned char *Ret = P + Length;
 148   uint32_t Offset = *((uint32_t *)P);
 149   if (Offset == 0) // is a CIE
 150     return Ret;
 151
 152   P += 4;
 153   intptr_t FDELocation = *((intptr_t *)P);
 154   intptr_t NewLocation = FDELocation - DeltaForText;
 155   *((intptr_t *)P) = NewLocation;
 156   P += sizeof(intptr_t);
 157
 158   // Skip the FDE address range
 159   P += sizeof(intptr_t);
 160
 161   uint8_t Augmentationsize = *P;
 162   P += 1;
 163   if (Augmentationsize != 0) {
 164     intptr_t LSDA = *((intptr_t *)P);
 165     intptr_t NewLSDA = LSDA - DeltaForEH;
 166     *((intptr_t *)P) = NewLSDA;
 167   }
 168
 169   return Ret;
 170 }
 171
 172 static intptr_t computeDelta(SectionEntry *A, SectionEntry *B) {
 173   intptr_t ObjDistance = A->ObjAddress - B->ObjAddress;
 174   intptr_t MemDistance = A->LoadAddress - B->LoadAddress;
 175   return ObjDistance - MemDistance;
 176 }
 177
 178 void RuntimeDyldMachO::registerEHFrames() {
 179
 180   if (!MemMgr)
 181     return;
 182   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 183     EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
 184     if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
 185         SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
 186       continue;
 187     SectionEntry *Text = &Sections[SectionInfo.TextSID];
 188     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
 189     SectionEntry *ExceptTab = nullptr;
 190     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
 191       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 192
 193     intptr_t DeltaForText = computeDelta(Text, EHFrame);
 194     intptr_t DeltaForEH = 0;
 195     if (ExceptTab)
 196       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 197
 198     unsigned char *P = EHFrame->Address;
 199     unsigned char *End = P + EHFrame->Size;
 200     do {
 201       P = processFDE(P, DeltaForText, DeltaForEH);
 202     } while (P != End);
 203
 204     MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
 205                              EHFrame->Size);
 206   }
 207   UnregisteredEHFrameSections.clear();
 208 }
 209
 210 std::unique_ptr<RuntimeDyldMachO>
 211 llvm::RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
 212   switch (Arch) {
 213   default:
 214     llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
 215     break;
 216   case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
 217   case Triple::arm64: return make_unique<RuntimeDyldMachOAArch64>(MM);
 218   case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
 219   case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
 220   }
 221 }
 222
 223 } // end namespace llvm