llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp

   1 //===-- RuntimeDyldMachO.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-=//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // Implementation of the MC-JIT runtime dynamic linker.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "RuntimeDyldMachO.h"
  14 #include "Targets/RuntimeDyldMachOAArch64.h"
  15 #include "Targets/RuntimeDyldMachOARM.h"
  16 #include "Targets/RuntimeDyldMachOI386.h"
  17 #include "Targets/RuntimeDyldMachOX86_64.h"
  18 #include "llvm/ADT/StringRef.h"
  19
  20 using namespace llvm;
  21 using namespace llvm::object;
  22
  23 #define DEBUG_TYPE "dyld"
  24
  25 namespace {
  26
  27 class LoadedMachOObjectInfo final
  28     : public LoadedObjectInfoHelper<LoadedMachOObjectInfo,
  29                                     RuntimeDyld::LoadedObjectInfo> {
  30 public:
  31   LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
  32                         ObjSectionToIDMap ObjSecToIDMap)
  33       : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
  34
  35   OwningBinary<ObjectFile>
  36   getObjectForDebug(const ObjectFile &Obj) const override {
  37     return OwningBinary<ObjectFile>();
  38   }
  39 };
  40
  41 }
  42
  43 namespace llvm {
  44
  45 int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
  46   unsigned NumBytes = 1 << RE.Size;
  47   uint8_t *Src = Sections[RE.SectionID].getAddress() + RE.Offset;
  48
  49   return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
  50 }
  51
  52 Expected<relocation_iterator>
  53 RuntimeDyldMachO::processScatteredVANILLA(
  54                           unsigned SectionID, relocation_iterator RelI,
  55                           const ObjectFile &BaseObjT,
  56                           RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID,
  57                           bool TargetIsLocalThumbFunc) {
  58   const MachOObjectFile &Obj =
  59     static_cast<const MachOObjectFile&>(BaseObjT);
  60   MachO::any_relocation_info RE =
  61     Obj.getRelocation(RelI->getRawDataRefImpl());
  62
  63   SectionEntry &Section = Sections[SectionID];
  64   uint32_t RelocType = Obj.getAnyRelocationType(RE);
  65   bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
  66   unsigned Size = Obj.getAnyRelocationLength(RE);
  67   uint64_t Offset = RelI->getOffset();
  68   uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
  69   unsigned NumBytes = 1 << Size;
  70   int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
  71
  72   unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
  73   section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
  74   assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
  75   uint64_t SectionBaseAddr = TargetSI->getAddress();
  76   SectionRef TargetSection = *TargetSI;
  77   bool IsCode = TargetSection.isText();
  78   uint32_t TargetSectionID = ~0U;
  79   if (auto TargetSectionIDOrErr =
  80         findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
  81     TargetSectionID = *TargetSectionIDOrErr;
  82   else
  83     return TargetSectionIDOrErr.takeError();
  84
  85   Addend -= SectionBaseAddr;
  86   RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
  87   R.IsTargetThumbFunc = TargetIsLocalThumbFunc;
  88
  89   addRelocationForSection(R, TargetSectionID);
  90
  91   return ++RelI;
  92 }
  93
  94
  95 Expected<RelocationValueRef>
  96 RuntimeDyldMachO::getRelocationValueRef(
  97     const ObjectFile &BaseTObj, const relocation_iterator &RI,
  98     const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
  99
 100   const MachOObjectFile &Obj =
 101       static_cast<const MachOObjectFile &>(BaseTObj);
 102   MachO::any_relocation_info RelInfo =
 103       Obj.getRelocation(RI->getRawDataRefImpl());
 104   RelocationValueRef Value;
 105
 106   bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
 107   if (IsExternal) {
 108     symbol_iterator Symbol = RI->getSymbol();
 109     StringRef TargetName;
 110     if (auto TargetNameOrErr = Symbol->getName())
 111       TargetName = *TargetNameOrErr;
 112     else
 113       return TargetNameOrErr.takeError();
 114     RTDyldSymbolTable::const_iterator SI =
 115       GlobalSymbolTable.find(TargetName.data());
 116     if (SI != GlobalSymbolTable.end()) {
 117       const auto &SymInfo = SI->second;
 118       Value.SectionID = SymInfo.getSectionID();
 119       Value.Offset = SymInfo.getOffset() + RE.Addend;
 120     } else {
 121       Value.SymbolName = TargetName.data();
 122       Value.Offset = RE.Addend;
 123     }
 124   } else {
 125     SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
 126     bool IsCode = Sec.isText();
 127     if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
 128                                                 ObjSectionToID))
 129       Value.SectionID = *SectionIDOrErr;
 130     else
 131       return SectionIDOrErr.takeError();
 132     uint64_t Addr = Sec.getAddress();
 133     Value.Offset = RE.Addend - Addr;
 134   }
 135
 136   return Value;
 137 }
 138
 139 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
 140                                             const relocation_iterator &RI,
 141                                             unsigned OffsetToNextPC) {
 142   auto &O = *cast<MachOObjectFile>(RI->getObject());
 143   section_iterator SecI = O.getRelocationRelocatedSection(RI);
 144   Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
 145 }
 146
 147 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
 148                                                uint64_t Value) const {
 149   const SectionEntry &Section = Sections[RE.SectionID];
 150   uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
 151   uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
 152
 153   dbgs() << "resolveRelocation Section: " << RE.SectionID
 154          << " LocalAddress: " << format("%p", LocalAddress)
 155          << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
 156          << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
 157          << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
 158          << " Size: " << (1 << RE.Size) << "\n";
 159 }
 160
 161 section_iterator
 162 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
 163                                       uint64_t Addr) {
 164   section_iterator SI = Obj.section_begin();
 165   section_iterator SE = Obj.section_end();
 166
 167   for (; SI != SE; ++SI) {
 168     uint64_t SAddr = SI->getAddress();
 169     uint64_t SSize = SI->getSize();
 170     if ((Addr >= SAddr) && (Addr < SAddr + SSize))
 171       return SI;
 172   }
 173
 174   return SE;
 175 }
 176
 177
 178 // Populate __pointers section.
 179 Error RuntimeDyldMachO::populateIndirectSymbolPointersSection(
 180                                                     const MachOObjectFile &Obj,
 181                                                     const SectionRef &PTSection,
 182                                                     unsigned PTSectionID) {
 183   assert(!Obj.is64Bit() &&
 184          "Pointer table section not supported in 64-bit MachO.");
 185
 186   MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
 187   MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
 188   uint32_t PTSectionSize = Sec32.size;
 189   unsigned FirstIndirectSymbol = Sec32.reserved1;
 190   const unsigned PTEntrySize = 4;
 191   unsigned NumPTEntries = PTSectionSize / PTEntrySize;
 192   unsigned PTEntryOffset = 0;
 193
 194   assert((PTSectionSize % PTEntrySize) == 0 &&
 195          "Pointers section does not contain a whole number of stubs?");
 196
 197   LLVM_DEBUG(dbgs() << "Populating pointer table section "
 198                     << Sections[PTSectionID].getName() << ", Section ID "
 199                     << PTSectionID << ", " << NumPTEntries << " entries, "
 200                     << PTEntrySize << " bytes each:\n");
 201
 202   for (unsigned i = 0; i < NumPTEntries; ++i) {
 203     unsigned SymbolIndex =
 204       Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
 205     symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
 206     StringRef IndirectSymbolName;
 207     if (auto IndirectSymbolNameOrErr = SI->getName())
 208       IndirectSymbolName = *IndirectSymbolNameOrErr;
 209     else
 210       return IndirectSymbolNameOrErr.takeError();
 211     LLVM_DEBUG(dbgs() << "  " << IndirectSymbolName << ": index " << SymbolIndex
 212                       << ", PT offset: " << PTEntryOffset << "\n");
 213     RelocationEntry RE(PTSectionID, PTEntryOffset,
 214                        MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
 215     addRelocationForSymbol(RE, IndirectSymbolName);
 216     PTEntryOffset += PTEntrySize;
 217   }
 218   return Error::success();
 219 }
 220
 221 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
 222   return Obj.isMachO();
 223 }
 224
 225 template <typename Impl>
 226 Error
 227 RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
 228                                              ObjSectionToIDMap &SectionMap) {
 229   unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
 230   unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
 231   unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
 232
 233   for (const auto &Section : Obj.sections()) {
 234     StringRef Name;
 235     if (Expected<StringRef> NameOrErr = Section.getName())
 236       Name = *NameOrErr;
 237     else
 238       consumeError(NameOrErr.takeError());
 239
 240     // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
 241     // if they're present. Otherwise call down to the impl to handle other
 242     // sections that have already been emitted.
 243     if (Name == "__text") {
 244       if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
 245         TextSID = *TextSIDOrErr;
 246       else
 247         return TextSIDOrErr.takeError();
 248     } else if (Name == "__eh_frame") {
 249       if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
 250                                                    SectionMap))
 251         EHFrameSID = *EHFrameSIDOrErr;
 252       else
 253         return EHFrameSIDOrErr.takeError();
 254     } else if (Name == "__gcc_except_tab") {
 255       if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
 256                                                      SectionMap))
 257         ExceptTabSID = *ExceptTabSIDOrErr;
 258       else
 259         return ExceptTabSIDOrErr.takeError();
 260     } else {
 261       auto I = SectionMap.find(Section);
 262       if (I != SectionMap.end())
 263         if (auto Err = impl().finalizeSection(Obj, I->second, Section))
 264           return Err;
 265     }
 266   }
 267   UnregisteredEHFrameSections.push_back(
 268     EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
 269
 270   return Error::success();
 271 }
 272
 273 template <typename Impl>
 274 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
 275                                                           int64_t DeltaForText,
 276                                                           int64_t DeltaForEH) {
 277   typedef typename Impl::TargetPtrT TargetPtrT;
 278
 279   LLVM_DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
 280                     << ", Delta for EH: " << DeltaForEH << "\n");
 281   uint32_t Length = readBytesUnaligned(P, 4);
 282   P += 4;
 283   uint8_t *Ret = P + Length;
 284   uint32_t Offset = readBytesUnaligned(P, 4);
 285   if (Offset == 0) // is a CIE
 286     return Ret;
 287
 288   P += 4;
 289   TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
 290   TargetPtrT NewLocation = FDELocation - DeltaForText;
 291   writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
 292
 293   P += sizeof(TargetPtrT);
 294
 295   // Skip the FDE address range
 296   P += sizeof(TargetPtrT);
 297
 298   uint8_t Augmentationsize = *P;
 299   P += 1;
 300   if (Augmentationsize != 0) {
 301     TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
 302     TargetPtrT NewLSDA = LSDA - DeltaForEH;
 303     writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
 304   }
 305
 306   return Ret;
 307 }
 308
 309 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
 310   int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
 311                         static_cast<int64_t>(B->getObjAddress());
 312   int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
 313   return ObjDistance - MemDistance;
 314 }
 315
 316 template <typename Impl>
 317 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
 318
 319   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 320     EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
 321     if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
 322         SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
 323       continue;
 324     SectionEntry *Text = &Sections[SectionInfo.TextSID];
 325     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
 326     SectionEntry *ExceptTab = nullptr;
 327     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
 328       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 329
 330     int64_t DeltaForText = computeDelta(Text, EHFrame);
 331     int64_t DeltaForEH = 0;
 332     if (ExceptTab)
 333       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 334
 335     uint8_t *P = EHFrame->getAddress();
 336     uint8_t *End = P + EHFrame->getSize();
 337     while (P != End) {
 338       P = processFDE(P, DeltaForText, DeltaForEH);
 339     }
 340
 341     MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
 342                             EHFrame->getSize());
 343   }
 344   UnregisteredEHFrameSections.clear();
 345 }
 346
 347 std::unique_ptr<RuntimeDyldMachO>
 348 RuntimeDyldMachO::create(Triple::ArchType Arch,
 349                          RuntimeDyld::MemoryManager &MemMgr,
 350                          JITSymbolResolver &Resolver) {
 351   switch (Arch) {
 352   default:
 353     llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
 354     break;
 355   case Triple::arm:
 356     return std::make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
 357   case Triple::aarch64:
 358     return std::make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
 359   case Triple::aarch64_32:
 360     return std::make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
 361   case Triple::x86:
 362     return std::make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
 363   case Triple::x86_64:
 364     return std::make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
 365   }
 366 }
 367
 368 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
 369 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
 370   if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
 371     return std::make_unique<LoadedMachOObjectInfo>(*this,
 372                                                     *ObjSectionToIDOrErr);
 373   else {
 374     HasError = true;
 375     raw_string_ostream ErrStream(ErrorStr);
 376     logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream);
 377     return nullptr;
 378   }
 379 }
 380
 381 } // end namespace llvm