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   unsigned NumBytes = 1 << RE.Size;
  32   uint8_t *Src = Sections[RE.SectionID].Address + RE.Offset;
  33
  34   return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
  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.Offset = 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.Offset = SI->second.second + RE.Addend;
  62       } else {
  63         Value.SymbolName = TargetName.data();
  64         Value.Offset = 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.Offset = 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                                             unsigned OffsetToNextPC) {
  84   const MachOObjectFile &Obj =
  85       static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
  86   MachO::any_relocation_info RelInfo =
  87       Obj.getRelocation(RI->getRawDataRefImpl());
  88
  89   bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
  90   if (IsPCRel) {
  91     uint64_t RelocAddr = 0;
  92     RI->getAddress(RelocAddr);
  93     Value.Offset += RelocAddr + OffsetToNextPC;
  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("0x%016" PRIx64, FinalAddress)
 106          << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
 107          << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
 108          << " Size: " << (1 << RE.Size) << "\n";
 109 }
 110
 111 bool
 112 RuntimeDyldMachO::isCompatibleFormat(const ObjectBuffer *InputBuffer) const {
 113   if (InputBuffer->getBufferSize() < 4)
 114     return false;
 115   StringRef Magic(InputBuffer->getBufferStart(), 4);
 116   if (Magic == "\xFE\xED\xFA\xCE")
 117     return true;
 118   if (Magic == "\xCE\xFA\xED\xFE")
 119     return true;
 120   if (Magic == "\xFE\xED\xFA\xCF")
 121     return true;
 122   if (Magic == "\xCF\xFA\xED\xFE")
 123     return true;
 124   return false;
 125 }
 126
 127 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile *Obj) const {
 128   return Obj->isMachO();
 129 }
 130
 131 template <typename Impl>
 132 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(ObjectImage &ObjImg,
 133                                                   ObjSectionToIDMap &SectionMap) {
 134   unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
 135   unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
 136   unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
 137   ObjSectionToIDMap::iterator i, e;
 138
 139   for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
 140     const SectionRef &Section = i->first;
 141     StringRef Name;
 142     Section.getName(Name);
 143     if (Name == "__eh_frame")
 144       EHFrameSID = i->second;
 145     else if (Name == "__text")
 146       TextSID = i->second;
 147     else if (Name == "__gcc_except_tab")
 148       ExceptTabSID = i->second;
 149     else
 150       impl().finalizeSection(ObjImg, i->second, Section);
 151   }
 152   UnregisteredEHFrameSections.push_back(
 153     EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
 154 }
 155
 156 template <typename Impl>
 157 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
 158                                                           int64_t DeltaForText,
 159                                                           int64_t DeltaForEH) {
 160   typedef typename Impl::TargetPtrT TargetPtrT;
 161
 162   DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
 163                << ", Delta for EH: " << DeltaForEH << "\n");
 164   uint32_t Length = *((uint32_t *)P);
 165   P += 4;
 166   unsigned char *Ret = P + Length;
 167   uint32_t Offset = *((uint32_t *)P);
 168   if (Offset == 0) // is a CIE
 169     return Ret;
 170
 171   P += 4;
 172   TargetPtrT FDELocation = *((TargetPtrT*)P);
 173   TargetPtrT NewLocation = FDELocation - DeltaForText;
 174   *((TargetPtrT*)P) = NewLocation;
 175   P += sizeof(TargetPtrT);
 176
 177   // Skip the FDE address range
 178   P += sizeof(TargetPtrT);
 179
 180   uint8_t Augmentationsize = *P;
 181   P += 1;
 182   if (Augmentationsize != 0) {
 183     TargetPtrT LSDA = *((TargetPtrT *)P);
 184     TargetPtrT NewLSDA = LSDA - DeltaForEH;
 185     *((TargetPtrT *)P) = NewLSDA;
 186   }
 187
 188   return Ret;
 189 }
 190
 191 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
 192   int64_t ObjDistance = A->ObjAddress - B->ObjAddress;
 193   int64_t MemDistance = A->LoadAddress - B->LoadAddress;
 194   return ObjDistance - MemDistance;
 195 }
 196
 197 template <typename Impl>
 198 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
 199
 200   if (!MemMgr)
 201     return;
 202   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 203     EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
 204     if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
 205         SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
 206       continue;
 207     SectionEntry *Text = &Sections[SectionInfo.TextSID];
 208     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
 209     SectionEntry *ExceptTab = nullptr;
 210     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
 211       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 212
 213     int64_t DeltaForText = computeDelta(Text, EHFrame);
 214     int64_t DeltaForEH = 0;
 215     if (ExceptTab)
 216       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 217
 218     unsigned char *P = EHFrame->Address;
 219     unsigned char *End = P + EHFrame->Size;
 220     do {
 221       P = processFDE(P, DeltaForText, DeltaForEH);
 222     } while (P != End);
 223
 224     MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
 225                              EHFrame->Size);
 226   }
 227   UnregisteredEHFrameSections.clear();
 228 }
 229
 230 std::unique_ptr<RuntimeDyldMachO>
 231 llvm::RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
 232   switch (Arch) {
 233   default:
 234     llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
 235     break;
 236   case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
 237   case Triple::aarch64: return make_unique<RuntimeDyldMachOAArch64>(MM);
 238   case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
 239   case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
 240   }
 241 }
 242
 243 } // end namespace llvm