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 final
  30     : public LoadedObjectInfoHelper<LoadedMachOObjectInfo,
  31                                     RuntimeDyld::LoadedObjectInfo> {
  32 public:
  33   LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
  34                         ObjSectionToIDMap ObjSecToIDMap)
  35       : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
  36
  37   OwningBinary<ObjectFile>
  38   getObjectForDebug(const ObjectFile &Obj) const override {
  39     return OwningBinary<ObjectFile>();
  40   }
  41 };
  42
  43 }
  44
  45 namespace llvm {
  46
  47 int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
  48   unsigned NumBytes = 1 << RE.Size;
  49   uint8_t *Src = Sections[RE.SectionID].getAddress() + RE.Offset;
  50
  51   return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
  52 }
  53
  54 Expected<relocation_iterator>
  55 RuntimeDyldMachO::processScatteredVANILLA(
  56                           unsigned SectionID, relocation_iterator RelI,
  57                           const ObjectFile &BaseObjT,
  58                           RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID,
  59                           bool TargetIsLocalThumbFunc) {
  60   const MachOObjectFile &Obj =
  61     static_cast<const MachOObjectFile&>(BaseObjT);
  62   MachO::any_relocation_info RE =
  63     Obj.getRelocation(RelI->getRawDataRefImpl());
  64
  65   SectionEntry &Section = Sections[SectionID];
  66   uint32_t RelocType = Obj.getAnyRelocationType(RE);
  67   bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
  68   unsigned Size = Obj.getAnyRelocationLength(RE);
  69   uint64_t Offset = RelI->getOffset();
  70   uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
  71   unsigned NumBytes = 1 << Size;
  72   int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
  73
  74   unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
  75   section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
  76   assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
  77   uint64_t SectionBaseAddr = TargetSI->getAddress();
  78   SectionRef TargetSection = *TargetSI;
  79   bool IsCode = TargetSection.isText();
  80   uint32_t TargetSectionID = ~0U;
  81   if (auto TargetSectionIDOrErr =
  82         findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
  83     TargetSectionID = *TargetSectionIDOrErr;
  84   else
  85     return TargetSectionIDOrErr.takeError();
  86
  87   Addend -= SectionBaseAddr;
  88   RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
  89   R.IsTargetThumbFunc = TargetIsLocalThumbFunc;
  90
  91   addRelocationForSection(R, TargetSectionID);
  92
  93   return ++RelI;
  94 }
  95
  96
  97 Expected<RelocationValueRef>
  98 RuntimeDyldMachO::getRelocationValueRef(
  99     const ObjectFile &BaseTObj, const relocation_iterator &RI,
 100     const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
 101
 102   const MachOObjectFile &Obj =
 103       static_cast<const MachOObjectFile &>(BaseTObj);
 104   MachO::any_relocation_info RelInfo =
 105       Obj.getRelocation(RI->getRawDataRefImpl());
 106   RelocationValueRef Value;
 107
 108   bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
 109   if (IsExternal) {
 110     symbol_iterator Symbol = RI->getSymbol();
 111     StringRef TargetName;
 112     if (auto TargetNameOrErr = Symbol->getName())
 113       TargetName = *TargetNameOrErr;
 114     else
 115       return TargetNameOrErr.takeError();
 116     RTDyldSymbolTable::const_iterator SI =
 117       GlobalSymbolTable.find(TargetName.data());
 118     if (SI != GlobalSymbolTable.end()) {
 119       const auto &SymInfo = SI->second;
 120       Value.SectionID = SymInfo.getSectionID();
 121       Value.Offset = SymInfo.getOffset() + RE.Addend;
 122     } else {
 123       Value.SymbolName = TargetName.data();
 124       Value.Offset = RE.Addend;
 125     }
 126   } else {
 127     SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
 128     bool IsCode = Sec.isText();
 129     if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
 130                                                 ObjSectionToID))
 131       Value.SectionID = *SectionIDOrErr;
 132     else
 133       return SectionIDOrErr.takeError();
 134     uint64_t Addr = Sec.getAddress();
 135     Value.Offset = RE.Addend - Addr;
 136   }
 137
 138   return Value;
 139 }
 140
 141 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
 142                                             const relocation_iterator &RI,
 143                                             unsigned OffsetToNextPC) {
 144   auto &O = *cast<MachOObjectFile>(RI->getObject());
 145   section_iterator SecI = O.getRelocationRelocatedSection(RI);
 146   Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
 147 }
 148
 149 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
 150                                                uint64_t Value) const {
 151   const SectionEntry &Section = Sections[RE.SectionID];
 152   uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
 153   uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
 154
 155   dbgs() << "resolveRelocation Section: " << RE.SectionID
 156          << " LocalAddress: " << format("%p", LocalAddress)
 157          << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
 158          << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
 159          << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
 160          << " Size: " << (1 << RE.Size) << "\n";
 161 }
 162
 163 section_iterator
 164 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
 165                                       uint64_t Addr) {
 166   section_iterator SI = Obj.section_begin();
 167   section_iterator SE = Obj.section_end();
 168
 169   for (; SI != SE; ++SI) {
 170     uint64_t SAddr = SI->getAddress();
 171     uint64_t SSize = SI->getSize();
 172     if ((Addr >= SAddr) && (Addr < SAddr + SSize))
 173       return SI;
 174   }
 175
 176   return SE;
 177 }
 178
 179
 180 // Populate __pointers section.
 181 Error RuntimeDyldMachO::populateIndirectSymbolPointersSection(
 182                                                     const MachOObjectFile &Obj,
 183                                                     const SectionRef &PTSection,
 184                                                     unsigned PTSectionID) {
 185   assert(!Obj.is64Bit() &&
 186          "Pointer table section not supported in 64-bit MachO.");
 187
 188   MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
 189   MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
 190   uint32_t PTSectionSize = Sec32.size;
 191   unsigned FirstIndirectSymbol = Sec32.reserved1;
 192   const unsigned PTEntrySize = 4;
 193   unsigned NumPTEntries = PTSectionSize / PTEntrySize;
 194   unsigned PTEntryOffset = 0;
 195
 196   assert((PTSectionSize % PTEntrySize) == 0 &&
 197          "Pointers section does not contain a whole number of stubs?");
 198
 199   LLVM_DEBUG(dbgs() << "Populating pointer table section "
 200                     << Sections[PTSectionID].getName() << ", Section ID "
 201                     << PTSectionID << ", " << NumPTEntries << " entries, "
 202                     << PTEntrySize << " bytes each:\n");
 203
 204   for (unsigned i = 0; i < NumPTEntries; ++i) {
 205     unsigned SymbolIndex =
 206       Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
 207     symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
 208     StringRef IndirectSymbolName;
 209     if (auto IndirectSymbolNameOrErr = SI->getName())
 210       IndirectSymbolName = *IndirectSymbolNameOrErr;
 211     else
 212       return IndirectSymbolNameOrErr.takeError();
 213     LLVM_DEBUG(dbgs() << "  " << IndirectSymbolName << ": index " << SymbolIndex
 214                       << ", PT offset: " << PTEntryOffset << "\n");
 215     RelocationEntry RE(PTSectionID, PTEntryOffset,
 216                        MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
 217     addRelocationForSymbol(RE, IndirectSymbolName);
 218     PTEntryOffset += PTEntrySize;
 219   }
 220   return Error::success();
 221 }
 222
 223 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
 224   return Obj.isMachO();
 225 }
 226
 227 template <typename Impl>
 228 Error
 229 RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
 230                                              ObjSectionToIDMap &SectionMap) {
 231   unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
 232   unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
 233   unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
 234
 235   for (const auto &Section : Obj.sections()) {
 236     StringRef Name;
 237     Section.getName(Name);
 238
 239     // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
 240     // if they're present. Otherwise call down to the impl to handle other
 241     // sections that have already been emitted.
 242     if (Name == "__text") {
 243       if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
 244         TextSID = *TextSIDOrErr;
 245       else
 246         return TextSIDOrErr.takeError();
 247     } else if (Name == "__eh_frame") {
 248       if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
 249                                                    SectionMap))
 250         EHFrameSID = *EHFrameSIDOrErr;
 251       else
 252         return EHFrameSIDOrErr.takeError();
 253     } else if (Name == "__gcc_except_tab") {
 254       if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
 255                                                      SectionMap))
 256         ExceptTabSID = *ExceptTabSIDOrErr;
 257       else
 258         return ExceptTabSIDOrErr.takeError();
 259     } else {
 260       auto I = SectionMap.find(Section);
 261       if (I != SectionMap.end())
 262         if (auto Err = impl().finalizeSection(Obj, I->second, Section))
 263           return Err;
 264     }
 265   }
 266   UnregisteredEHFrameSections.push_back(
 267     EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
 268
 269   return Error::success();
 270 }
 271
 272 template <typename Impl>
 273 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
 274                                                           int64_t DeltaForText,
 275                                                           int64_t DeltaForEH) {
 276   typedef typename Impl::TargetPtrT TargetPtrT;
 277
 278   LLVM_DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
 279                     << ", Delta for EH: " << DeltaForEH << "\n");
 280   uint32_t Length = readBytesUnaligned(P, 4);
 281   P += 4;
 282   uint8_t *Ret = P + Length;
 283   uint32_t Offset = readBytesUnaligned(P, 4);
 284   if (Offset == 0) // is a CIE
 285     return Ret;
 286
 287   P += 4;
 288   TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
 289   TargetPtrT NewLocation = FDELocation - DeltaForText;
 290   writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
 291
 292   P += sizeof(TargetPtrT);
 293
 294   // Skip the FDE address range
 295   P += sizeof(TargetPtrT);
 296
 297   uint8_t Augmentationsize = *P;
 298   P += 1;
 299   if (Augmentationsize != 0) {
 300     TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
 301     TargetPtrT NewLSDA = LSDA - DeltaForEH;
 302     writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
 303   }
 304
 305   return Ret;
 306 }
 307
 308 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
 309   int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
 310                         static_cast<int64_t>(B->getObjAddress());
 311   int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
 312   return ObjDistance - MemDistance;
 313 }
 314
 315 template <typename Impl>
 316 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
 317
 318   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 319     EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
 320     if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
 321         SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
 322       continue;
 323     SectionEntry *Text = &Sections[SectionInfo.TextSID];
 324     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
 325     SectionEntry *ExceptTab = nullptr;
 326     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
 327       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 328
 329     int64_t DeltaForText = computeDelta(Text, EHFrame);
 330     int64_t DeltaForEH = 0;
 331     if (ExceptTab)
 332       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 333
 334     uint8_t *P = EHFrame->getAddress();
 335     uint8_t *End = P + EHFrame->getSize();
 336     while (P != End) {
 337       P = processFDE(P, DeltaForText, DeltaForEH);
 338     }
 339
 340     MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
 341                             EHFrame->getSize());
 342   }
 343   UnregisteredEHFrameSections.clear();
 344 }
 345
 346 std::unique_ptr<RuntimeDyldMachO>
 347 RuntimeDyldMachO::create(Triple::ArchType Arch,
 348                          RuntimeDyld::MemoryManager &MemMgr,
 349                          JITSymbolResolver &Resolver) {
 350   switch (Arch) {
 351   default:
 352     llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
 353     break;
 354   case Triple::arm:
 355     return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
 356   case Triple::aarch64:
 357     return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
 358   case Triple::x86:
 359     return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
 360   case Triple::x86_64:
 361     return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
 362   }
 363 }
 364
 365 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
 366 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
 367   if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
 368     return llvm::make_unique<LoadedMachOObjectInfo>(*this,
 369                                                     *ObjSectionToIDOrErr);
 370   else {
 371     HasError = true;
 372     raw_string_ostream ErrStream(ErrorStr);
 373     logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream);
 374     return nullptr;
 375   }
 376 }
 377
 378 } // end namespace llvm