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