contrib/llvm-project/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

   1 //===-- RuntimeDyldELF.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 ELF support for the MC-JIT runtime dynamic linker.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "RuntimeDyldELF.h"
  14 #include "RuntimeDyldCheckerImpl.h"
  15 #include "Targets/RuntimeDyldELFMips.h"
  16 #include "llvm/ADT/STLExtras.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/ADT/Triple.h"
  19 #include "llvm/BinaryFormat/ELF.h"
  20 #include "llvm/Object/ELFObjectFile.h"
  21 #include "llvm/Object/ObjectFile.h"
  22 #include "llvm/Support/Endian.h"
  23 #include "llvm/Support/MemoryBuffer.h"
  24
  25 using namespace llvm;
  26 using namespace llvm::object;
  27 using namespace llvm::support::endian;
  28
  29 #define DEBUG_TYPE "dyld"
  30
  31 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); }
  32
  33 static void or32AArch64Imm(void *L, uint64_t Imm) {
  34   or32le(L, (Imm & 0xFFF) << 10);
  35 }
  36
  37 template <class T> static void write(bool isBE, void *P, T V) {
  38   isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V);
  39 }
  40
  41 static void write32AArch64Addr(void *L, uint64_t Imm) {
  42   uint32_t ImmLo = (Imm & 0x3) << 29;
  43   uint32_t ImmHi = (Imm & 0x1FFFFC) << 3;
  44   uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3);
  45   write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi);
  46 }
  47
  48 // Return the bits [Start, End] from Val shifted Start bits.
  49 // For instance, getBits(0xF0, 4, 8) returns 0xF.
  50 static uint64_t getBits(uint64_t Val, int Start, int End) {
  51   uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1;
  52   return (Val >> Start) & Mask;
  53 }
  54
  55 namespace {
  56
  57 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> {
  58   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
  59
  60   typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
  61   typedef Elf_Sym_Impl<ELFT> Elf_Sym;
  62   typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
  63   typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
  64
  65   typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
  66
  67   typedef typename ELFT::uint addr_type;
  68
  69   DyldELFObject(ELFObjectFile<ELFT> &&Obj);
  70
  71 public:
  72   static Expected<std::unique_ptr<DyldELFObject>>
  73   create(MemoryBufferRef Wrapper);
  74
  75   void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
  76
  77   void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr);
  78
  79   // Methods for type inquiry through isa, cast and dyn_cast
  80   static bool classof(const Binary *v) {
  81     return (isa<ELFObjectFile<ELFT>>(v) &&
  82             classof(cast<ELFObjectFile<ELFT>>(v)));
  83   }
  84   static bool classof(const ELFObjectFile<ELFT> *v) {
  85     return v->isDyldType();
  86   }
  87 };
  88
  89
  90
  91 // The MemoryBuffer passed into this constructor is just a wrapper around the
  92 // actual memory.  Ultimately, the Binary parent class will take ownership of
  93 // this MemoryBuffer object but not the underlying memory.
  94 template <class ELFT>
  95 DyldELFObject<ELFT>::DyldELFObject(ELFObjectFile<ELFT> &&Obj)
  96     : ELFObjectFile<ELFT>(std::move(Obj)) {
  97   this->isDyldELFObject = true;
  98 }
  99
 100 template <class ELFT>
 101 Expected<std::unique_ptr<DyldELFObject<ELFT>>>
 102 DyldELFObject<ELFT>::create(MemoryBufferRef Wrapper) {
 103   auto Obj = ELFObjectFile<ELFT>::create(Wrapper);
 104   if (auto E = Obj.takeError())
 105     return std::move(E);
 106   std::unique_ptr<DyldELFObject<ELFT>> Ret(
 107       new DyldELFObject<ELFT>(std::move(*Obj)));
 108   return std::move(Ret);
 109 }
 110
 111 template <class ELFT>
 112 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
 113                                                uint64_t Addr) {
 114   DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
 115   Elf_Shdr *shdr =
 116       const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
 117
 118   // This assumes the address passed in matches the target address bitness
 119   // The template-based type cast handles everything else.
 120   shdr->sh_addr = static_cast<addr_type>(Addr);
 121 }
 122
 123 template <class ELFT>
 124 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
 125                                               uint64_t Addr) {
 126
 127   Elf_Sym *sym = const_cast<Elf_Sym *>(
 128       ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
 129
 130   // This assumes the address passed in matches the target address bitness
 131   // The template-based type cast handles everything else.
 132   sym->st_value = static_cast<addr_type>(Addr);
 133 }
 134
 135 class LoadedELFObjectInfo final
 136     : public LoadedObjectInfoHelper<LoadedELFObjectInfo,
 137                                     RuntimeDyld::LoadedObjectInfo> {
 138 public:
 139   LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
 140       : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
 141
 142   OwningBinary<ObjectFile>
 143   getObjectForDebug(const ObjectFile &Obj) const override;
 144 };
 145
 146 template <typename ELFT>
 147 static Expected<std::unique_ptr<DyldELFObject<ELFT>>>
 148 createRTDyldELFObject(MemoryBufferRef Buffer, const ObjectFile &SourceObject,
 149                       const LoadedELFObjectInfo &L) {
 150   typedef typename ELFT::Shdr Elf_Shdr;
 151   typedef typename ELFT::uint addr_type;
 152
 153   Expected<std::unique_ptr<DyldELFObject<ELFT>>> ObjOrErr =
 154       DyldELFObject<ELFT>::create(Buffer);
 155   if (Error E = ObjOrErr.takeError())
 156     return std::move(E);
 157
 158   std::unique_ptr<DyldELFObject<ELFT>> Obj = std::move(*ObjOrErr);
 159
 160   // Iterate over all sections in the object.
 161   auto SI = SourceObject.section_begin();
 162   for (const auto &Sec : Obj->sections()) {
 163     StringRef SectionName;
 164     Sec.getName(SectionName);
 165     if (SectionName != "") {
 166       DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
 167       Elf_Shdr *shdr = const_cast<Elf_Shdr *>(
 168           reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
 169
 170       if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) {
 171         // This assumes that the address passed in matches the target address
 172         // bitness. The template-based type cast handles everything else.
 173         shdr->sh_addr = static_cast<addr_type>(SecLoadAddr);
 174       }
 175     }
 176     ++SI;
 177   }
 178
 179   return std::move(Obj);
 180 }
 181
 182 static OwningBinary<ObjectFile>
 183 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) {
 184   assert(Obj.isELF() && "Not an ELF object file.");
 185
 186   std::unique_ptr<MemoryBuffer> Buffer =
 187     MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName());
 188
 189   Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr);
 190   handleAllErrors(DebugObj.takeError());
 191   if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian())
 192     DebugObj =
 193         createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L);
 194   else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian())
 195     DebugObj =
 196         createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L);
 197   else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian())
 198     DebugObj =
 199         createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L);
 200   else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian())
 201     DebugObj =
 202         createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L);
 203   else
 204     llvm_unreachable("Unexpected ELF format");
 205
 206   handleAllErrors(DebugObj.takeError());
 207   return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer));
 208 }
 209
 210 OwningBinary<ObjectFile>
 211 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const {
 212   return createELFDebugObject(Obj, *this);
 213 }
 214
 215 } // anonymous namespace
 216
 217 namespace llvm {
 218
 219 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr,
 220                                JITSymbolResolver &Resolver)
 221     : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {}
 222 RuntimeDyldELF::~RuntimeDyldELF() {}
 223
 224 void RuntimeDyldELF::registerEHFrames() {
 225   for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
 226     SID EHFrameSID = UnregisteredEHFrameSections[i];
 227     uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
 228     uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
 229     size_t EHFrameSize = Sections[EHFrameSID].getSize();
 230     MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
 231   }
 232   UnregisteredEHFrameSections.clear();
 233 }
 234
 235 std::unique_ptr<RuntimeDyldELF>
 236 llvm::RuntimeDyldELF::create(Triple::ArchType Arch,
 237                              RuntimeDyld::MemoryManager &MemMgr,
 238                              JITSymbolResolver &Resolver) {
 239   switch (Arch) {
 240   default:
 241     return make_unique<RuntimeDyldELF>(MemMgr, Resolver);
 242   case Triple::mips:
 243   case Triple::mipsel:
 244   case Triple::mips64:
 245   case Triple::mips64el:
 246     return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver);
 247   }
 248 }
 249
 250 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
 251 RuntimeDyldELF::loadObject(const object::ObjectFile &O) {
 252   if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
 253     return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr);
 254   else {
 255     HasError = true;
 256     raw_string_ostream ErrStream(ErrorStr);
 257     logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream);
 258     return nullptr;
 259   }
 260 }
 261
 262 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
 263                                              uint64_t Offset, uint64_t Value,
 264                                              uint32_t Type, int64_t Addend,
 265                                              uint64_t SymOffset) {
 266   switch (Type) {
 267   default:
 268     llvm_unreachable("Relocation type not implemented yet!");
 269     break;
 270   case ELF::R_X86_64_NONE:
 271     break;
 272   case ELF::R_X86_64_64: {
 273     support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) =
 274         Value + Addend;
 275     LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
 276                       << format("%p\n", Section.getAddressWithOffset(Offset)));
 277     break;
 278   }
 279   case ELF::R_X86_64_32:
 280   case ELF::R_X86_64_32S: {
 281     Value += Addend;
 282     assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
 283            (Type == ELF::R_X86_64_32S &&
 284             ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
 285     uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
 286     support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
 287         TruncatedAddr;
 288     LLVM_DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at "
 289                       << format("%p\n", Section.getAddressWithOffset(Offset)));
 290     break;
 291   }
 292   case ELF::R_X86_64_PC8: {
 293     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 294     int64_t RealOffset = Value + Addend - FinalAddress;
 295     assert(isInt<8>(RealOffset));
 296     int8_t TruncOffset = (RealOffset & 0xFF);
 297     Section.getAddress()[Offset] = TruncOffset;
 298     break;
 299   }
 300   case ELF::R_X86_64_PC32: {
 301     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 302     int64_t RealOffset = Value + Addend - FinalAddress;
 303     assert(isInt<32>(RealOffset));
 304     int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
 305     support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
 306         TruncOffset;
 307     break;
 308   }
 309   case ELF::R_X86_64_PC64: {
 310     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 311     int64_t RealOffset = Value + Addend - FinalAddress;
 312     support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) =
 313         RealOffset;
 314     LLVM_DEBUG(dbgs() << "Writing " << format("%p", RealOffset) << " at "
 315                       << format("%p\n", FinalAddress));
 316     break;
 317   }
 318   case ELF::R_X86_64_GOTOFF64: {
 319     // Compute Value - GOTBase.
 320     uint64_t GOTBase = 0;
 321     for (const auto &Section : Sections) {
 322       if (Section.getName() == ".got") {
 323         GOTBase = Section.getLoadAddressWithOffset(0);
 324         break;
 325       }
 326     }
 327     assert(GOTBase != 0 && "missing GOT");
 328     int64_t GOTOffset = Value - GOTBase + Addend;
 329     support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = GOTOffset;
 330     break;
 331   }
 332   }
 333 }
 334
 335 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
 336                                           uint64_t Offset, uint32_t Value,
 337                                           uint32_t Type, int32_t Addend) {
 338   switch (Type) {
 339   case ELF::R_386_32: {
 340     support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
 341         Value + Addend;
 342     break;
 343   }
 344   // Handle R_386_PLT32 like R_386_PC32 since it should be able to
 345   // reach any 32 bit address.
 346   case ELF::R_386_PLT32:
 347   case ELF::R_386_PC32: {
 348     uint32_t FinalAddress =
 349         Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
 350     uint32_t RealOffset = Value + Addend - FinalAddress;
 351     support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
 352         RealOffset;
 353     break;
 354   }
 355   default:
 356     // There are other relocation types, but it appears these are the
 357     // only ones currently used by the LLVM ELF object writer
 358     llvm_unreachable("Relocation type not implemented yet!");
 359     break;
 360   }
 361 }
 362
 363 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
 364                                               uint64_t Offset, uint64_t Value,
 365                                               uint32_t Type, int64_t Addend) {
 366   uint32_t *TargetPtr =
 367       reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
 368   uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 369   // Data should use target endian. Code should always use little endian.
 370   bool isBE = Arch == Triple::aarch64_be;
 371
 372   LLVM_DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
 373                     << format("%llx", Section.getAddressWithOffset(Offset))
 374                     << " FinalAddress: 0x" << format("%llx", FinalAddress)
 375                     << " Value: 0x" << format("%llx", Value) << " Type: 0x"
 376                     << format("%x", Type) << " Addend: 0x"
 377                     << format("%llx", Addend) << "\n");
 378
 379   switch (Type) {
 380   default:
 381     llvm_unreachable("Relocation type not implemented yet!");
 382     break;
 383   case ELF::R_AARCH64_ABS16: {
 384     uint64_t Result = Value + Addend;
 385     assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX);
 386     write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU));
 387     break;
 388   }
 389   case ELF::R_AARCH64_ABS32: {
 390     uint64_t Result = Value + Addend;
 391     assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX);
 392     write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
 393     break;
 394   }
 395   case ELF::R_AARCH64_ABS64:
 396     write(isBE, TargetPtr, Value + Addend);
 397     break;
 398   case ELF::R_AARCH64_PREL32: {
 399     uint64_t Result = Value + Addend - FinalAddress;
 400     assert(static_cast<int64_t>(Result) >= INT32_MIN &&
 401            static_cast<int64_t>(Result) <= UINT32_MAX);
 402     write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
 403     break;
 404   }
 405   case ELF::R_AARCH64_PREL64:
 406     write(isBE, TargetPtr, Value + Addend - FinalAddress);
 407     break;
 408   case ELF::R_AARCH64_CALL26: // fallthrough
 409   case ELF::R_AARCH64_JUMP26: {
 410     // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
 411     // calculation.
 412     uint64_t BranchImm = Value + Addend - FinalAddress;
 413
 414     // "Check that -2^27 <= result < 2^27".
 415     assert(isInt<28>(BranchImm));
 416     or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2);
 417     break;
 418   }
 419   case ELF::R_AARCH64_MOVW_UABS_G3:
 420     or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43);
 421     break;
 422   case ELF::R_AARCH64_MOVW_UABS_G2_NC:
 423     or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27);
 424     break;
 425   case ELF::R_AARCH64_MOVW_UABS_G1_NC:
 426     or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11);
 427     break;
 428   case ELF::R_AARCH64_MOVW_UABS_G0_NC:
 429     or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5);
 430     break;
 431   case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
 432     // Operation: Page(S+A) - Page(P)
 433     uint64_t Result =
 434         ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
 435
 436     // Check that -2^32 <= X < 2^32
 437     assert(isInt<33>(Result) && "overflow check failed for relocation");
 438
 439     // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
 440     // from bits 32:12 of X.
 441     write32AArch64Addr(TargetPtr, Result >> 12);
 442     break;
 443   }
 444   case ELF::R_AARCH64_ADD_ABS_LO12_NC:
 445     // Operation: S + A
 446     // Immediate goes in bits 21:10 of LD/ST instruction, taken
 447     // from bits 11:0 of X
 448     or32AArch64Imm(TargetPtr, Value + Addend);
 449     break;
 450   case ELF::R_AARCH64_LDST8_ABS_LO12_NC:
 451     // Operation: S + A
 452     // Immediate goes in bits 21:10 of LD/ST instruction, taken
 453     // from bits 11:0 of X
 454     or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11));
 455     break;
 456   case ELF::R_AARCH64_LDST16_ABS_LO12_NC:
 457     // Operation: S + A
 458     // Immediate goes in bits 21:10 of LD/ST instruction, taken
 459     // from bits 11:1 of X
 460     or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11));
 461     break;
 462   case ELF::R_AARCH64_LDST32_ABS_LO12_NC:
 463     // Operation: S + A
 464     // Immediate goes in bits 21:10 of LD/ST instruction, taken
 465     // from bits 11:2 of X
 466     or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11));
 467     break;
 468   case ELF::R_AARCH64_LDST64_ABS_LO12_NC:
 469     // Operation: S + A
 470     // Immediate goes in bits 21:10 of LD/ST instruction, taken
 471     // from bits 11:3 of X
 472     or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11));
 473     break;
 474   case ELF::R_AARCH64_LDST128_ABS_LO12_NC:
 475     // Operation: S + A
 476     // Immediate goes in bits 21:10 of LD/ST instruction, taken
 477     // from bits 11:4 of X
 478     or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11));
 479     break;
 480   }
 481 }
 482
 483 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
 484                                           uint64_t Offset, uint32_t Value,
 485                                           uint32_t Type, int32_t Addend) {
 486   // TODO: Add Thumb relocations.
 487   uint32_t *TargetPtr =
 488       reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
 489   uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
 490   Value += Addend;
 491
 492   LLVM_DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
 493                     << Section.getAddressWithOffset(Offset)
 494                     << " FinalAddress: " << format("%p", FinalAddress)
 495                     << " Value: " << format("%x", Value)
 496                     << " Type: " << format("%x", Type)
 497                     << " Addend: " << format("%x", Addend) << "\n");
 498
 499   switch (Type) {
 500   default:
 501     llvm_unreachable("Not implemented relocation type!");
 502
 503   case ELF::R_ARM_NONE:
 504     break;
 505     // Write a 31bit signed offset
 506   case ELF::R_ARM_PREL31:
 507     support::ulittle32_t::ref{TargetPtr} =
 508         (support::ulittle32_t::ref{TargetPtr} & 0x80000000) |
 509         ((Value - FinalAddress) & ~0x80000000);
 510     break;
 511   case ELF::R_ARM_TARGET1:
 512   case ELF::R_ARM_ABS32:
 513     support::ulittle32_t::ref{TargetPtr} = Value;
 514     break;
 515     // Write first 16 bit of 32 bit value to the mov instruction.
 516     // Last 4 bit should be shifted.
 517   case ELF::R_ARM_MOVW_ABS_NC:
 518   case ELF::R_ARM_MOVT_ABS:
 519     if (Type == ELF::R_ARM_MOVW_ABS_NC)
 520       Value = Value & 0xFFFF;
 521     else if (Type == ELF::R_ARM_MOVT_ABS)
 522       Value = (Value >> 16) & 0xFFFF;
 523     support::ulittle32_t::ref{TargetPtr} =
 524         (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) |
 525         (((Value >> 12) & 0xF) << 16);
 526     break;
 527     // Write 24 bit relative value to the branch instruction.
 528   case ELF::R_ARM_PC24: // Fall through.
 529   case ELF::R_ARM_CALL: // Fall through.
 530   case ELF::R_ARM_JUMP24:
 531     int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
 532     RelValue = (RelValue & 0x03FFFFFC) >> 2;
 533     assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE);
 534     support::ulittle32_t::ref{TargetPtr} =
 535         (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue;
 536     break;
 537   }
 538 }
 539
 540 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) {
 541   if (Arch == Triple::UnknownArch ||
 542       !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) {
 543     IsMipsO32ABI = false;
 544     IsMipsN32ABI = false;
 545     IsMipsN64ABI = false;
 546     return;
 547   }
 548   if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) {
 549     unsigned AbiVariant = E->getPlatformFlags();
 550     IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32;
 551     IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2;
 552   }
 553   IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips");
 554 }
 555
 556 // Return the .TOC. section and offset.
 557 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj,
 558                                           ObjSectionToIDMap &LocalSections,
 559                                           RelocationValueRef &Rel) {
 560   // Set a default SectionID in case we do not find a TOC section below.
 561   // This may happen for references to TOC base base (sym@toc, .odp
 562   // relocation) without a .toc directive.  In this case just use the
 563   // first section (which is usually the .odp) since the code won't
 564   // reference the .toc base directly.
 565   Rel.SymbolName = nullptr;
 566   Rel.SectionID = 0;
 567
 568   // The TOC consists of sections .got, .toc, .tocbss, .plt in that
 569   // order. The TOC starts where the first of these sections starts.
 570   for (auto &Section: Obj.sections()) {
 571     StringRef SectionName;
 572     if (auto EC = Section.getName(SectionName))
 573       return errorCodeToError(EC);
 574
 575     if (SectionName == ".got"
 576         || SectionName == ".toc"
 577         || SectionName == ".tocbss"
 578         || SectionName == ".plt") {
 579       if (auto SectionIDOrErr =
 580             findOrEmitSection(Obj, Section, false, LocalSections))
 581         Rel.SectionID = *SectionIDOrErr;
 582       else
 583         return SectionIDOrErr.takeError();
 584       break;
 585     }
 586   }
 587
 588   // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
 589   // thus permitting a full 64 Kbytes segment.
 590   Rel.Addend = 0x8000;
 591
 592   return Error::success();
 593 }
 594
 595 // Returns the sections and offset associated with the ODP entry referenced
 596 // by Symbol.
 597 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
 598                                           ObjSectionToIDMap &LocalSections,
 599                                           RelocationValueRef &Rel) {
 600   // Get the ELF symbol value (st_value) to compare with Relocation offset in
 601   // .opd entries
 602   for (section_iterator si = Obj.section_begin(), se = Obj.section_end();
 603        si != se; ++si) {
 604     section_iterator RelSecI = si->getRelocatedSection();
 605     if (RelSecI == Obj.section_end())
 606       continue;
 607
 608     StringRef RelSectionName;
 609     if (auto EC = RelSecI->getName(RelSectionName))
 610       return errorCodeToError(EC);
 611
 612     if (RelSectionName != ".opd")
 613       continue;
 614
 615     for (elf_relocation_iterator i = si->relocation_begin(),
 616                                  e = si->relocation_end();
 617          i != e;) {
 618       // The R_PPC64_ADDR64 relocation indicates the first field
 619       // of a .opd entry
 620       uint64_t TypeFunc = i->getType();
 621       if (TypeFunc != ELF::R_PPC64_ADDR64) {
 622         ++i;
 623         continue;
 624       }
 625
 626       uint64_t TargetSymbolOffset = i->getOffset();
 627       symbol_iterator TargetSymbol = i->getSymbol();
 628       int64_t Addend;
 629       if (auto AddendOrErr = i->getAddend())
 630         Addend = *AddendOrErr;
 631       else
 632         return AddendOrErr.takeError();
 633
 634       ++i;
 635       if (i == e)
 636         break;
 637
 638       // Just check if following relocation is a R_PPC64_TOC
 639       uint64_t TypeTOC = i->getType();
 640       if (TypeTOC != ELF::R_PPC64_TOC)
 641         continue;
 642
 643       // Finally compares the Symbol value and the target symbol offset
 644       // to check if this .opd entry refers to the symbol the relocation
 645       // points to.
 646       if (Rel.Addend != (int64_t)TargetSymbolOffset)
 647         continue;
 648
 649       section_iterator TSI = Obj.section_end();
 650       if (auto TSIOrErr = TargetSymbol->getSection())
 651         TSI = *TSIOrErr;
 652       else
 653         return TSIOrErr.takeError();
 654       assert(TSI != Obj.section_end() && "TSI should refer to a valid section");
 655
 656       bool IsCode = TSI->isText();
 657       if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode,
 658                                                   LocalSections))
 659         Rel.SectionID = *SectionIDOrErr;
 660       else
 661         return SectionIDOrErr.takeError();
 662       Rel.Addend = (intptr_t)Addend;
 663       return Error::success();
 664     }
 665   }
 666   llvm_unreachable("Attempting to get address of ODP entry!");
 667 }
 668
 669 // Relocation masks following the #lo(value), #hi(value), #ha(value),
 670 // #higher(value), #highera(value), #highest(value), and #highesta(value)
 671 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
 672 // document.
 673
 674 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
 675
 676 static inline uint16_t applyPPChi(uint64_t value) {
 677   return (value >> 16) & 0xffff;
 678 }
 679
 680 static inline uint16_t applyPPCha (uint64_t value) {
 681   return ((value + 0x8000) >> 16) & 0xffff;
 682 }
 683
 684 static inline uint16_t applyPPChigher(uint64_t value) {
 685   return (value >> 32) & 0xffff;
 686 }
 687
 688 static inline uint16_t applyPPChighera (uint64_t value) {
 689   return ((value + 0x8000) >> 32) & 0xffff;
 690 }
 691
 692 static inline uint16_t applyPPChighest(uint64_t value) {
 693   return (value >> 48) & 0xffff;
 694 }
 695
 696 static inline uint16_t applyPPChighesta (uint64_t value) {
 697   return ((value + 0x8000) >> 48) & 0xffff;
 698 }
 699
 700 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section,
 701                                             uint64_t Offset, uint64_t Value,
 702                                             uint32_t Type, int64_t Addend) {
 703   uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
 704   switch (Type) {
 705   default:
 706     llvm_unreachable("Relocation type not implemented yet!");
 707     break;
 708   case ELF::R_PPC_ADDR16_LO:
 709     writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
 710     break;
 711   case ELF::R_PPC_ADDR16_HI:
 712     writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
 713     break;
 714   case ELF::R_PPC_ADDR16_HA:
 715     writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
 716     break;
 717   }
 718 }
 719
 720 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
 721                                             uint64_t Offset, uint64_t Value,
 722                                             uint32_t Type, int64_t Addend) {
 723   uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
 724   switch (Type) {
 725   default:
 726     llvm_unreachable("Relocation type not implemented yet!");
 727     break;
 728   case ELF::R_PPC64_ADDR16:
 729     writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
 730     break;
 731   case ELF::R_PPC64_ADDR16_DS:
 732     writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
 733     break;
 734   case ELF::R_PPC64_ADDR16_LO:
 735     writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
 736     break;
 737   case ELF::R_PPC64_ADDR16_LO_DS:
 738     writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
 739     break;
 740   case ELF::R_PPC64_ADDR16_HI:
 741   case ELF::R_PPC64_ADDR16_HIGH:
 742     writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
 743     break;
 744   case ELF::R_PPC64_ADDR16_HA:
 745   case ELF::R_PPC64_ADDR16_HIGHA:
 746     writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
 747     break;
 748   case ELF::R_PPC64_ADDR16_HIGHER:
 749     writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
 750     break;
 751   case ELF::R_PPC64_ADDR16_HIGHERA:
 752     writeInt16BE(LocalAddress, applyPPChighera(Value + Addend));
 753     break;
 754   case ELF::R_PPC64_ADDR16_HIGHEST:
 755     writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
 756     break;
 757   case ELF::R_PPC64_ADDR16_HIGHESTA:
 758     writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend));
 759     break;
 760   case ELF::R_PPC64_ADDR14: {
 761     assert(((Value + Addend) & 3) == 0);
 762     // Preserve the AA/LK bits in the branch instruction
 763     uint8_t aalk = *(LocalAddress + 3);
 764     writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
 765   } break;
 766   case ELF::R_PPC64_REL16_LO: {
 767     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 768     uint64_t Delta = Value - FinalAddress + Addend;
 769     writeInt16BE(LocalAddress, applyPPClo(Delta));
 770   } break;
 771   case ELF::R_PPC64_REL16_HI: {
 772     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 773     uint64_t Delta = Value - FinalAddress + Addend;
 774     writeInt16BE(LocalAddress, applyPPChi(Delta));
 775   } break;
 776   case ELF::R_PPC64_REL16_HA: {
 777     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 778     uint64_t Delta = Value - FinalAddress + Addend;
 779     writeInt16BE(LocalAddress, applyPPCha(Delta));
 780   } break;
 781   case ELF::R_PPC64_ADDR32: {
 782     int64_t Result = static_cast<int64_t>(Value + Addend);
 783     if (SignExtend64<32>(Result) != Result)
 784       llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
 785     writeInt32BE(LocalAddress, Result);
 786   } break;
 787   case ELF::R_PPC64_REL24: {
 788     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 789     int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
 790     if (SignExtend64<26>(delta) != delta)
 791       llvm_unreachable("Relocation R_PPC64_REL24 overflow");
 792     // We preserve bits other than LI field, i.e. PO and AA/LK fields.
 793     uint32_t Inst = readBytesUnaligned(LocalAddress, 4);
 794     writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC));
 795   } break;
 796   case ELF::R_PPC64_REL32: {
 797     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 798     int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
 799     if (SignExtend64<32>(delta) != delta)
 800       llvm_unreachable("Relocation R_PPC64_REL32 overflow");
 801     writeInt32BE(LocalAddress, delta);
 802   } break;
 803   case ELF::R_PPC64_REL64: {
 804     uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
 805     uint64_t Delta = Value - FinalAddress + Addend;
 806     writeInt64BE(LocalAddress, Delta);
 807   } break;
 808   case ELF::R_PPC64_ADDR64:
 809     writeInt64BE(LocalAddress, Value + Addend);
 810     break;
 811   }
 812 }
 813
 814 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
 815                                               uint64_t Offset, uint64_t Value,
 816                                               uint32_t Type, int64_t Addend) {
 817   uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
 818   switch (Type) {
 819   default:
 820     llvm_unreachable("Relocation type not implemented yet!");
 821     break;
 822   case ELF::R_390_PC16DBL:
 823   case ELF::R_390_PLT16DBL: {
 824     int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
 825     assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
 826     writeInt16BE(LocalAddress, Delta / 2);
 827     break;
 828   }
 829   case ELF::R_390_PC32DBL:
 830   case ELF::R_390_PLT32DBL: {
 831     int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
 832     assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
 833     writeInt32BE(LocalAddress, Delta / 2);
 834     break;
 835   }
 836   case ELF::R_390_PC16: {
 837     int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
 838     assert(int16_t(Delta) == Delta && "R_390_PC16 overflow");
 839     writeInt16BE(LocalAddress, Delta);
 840     break;
 841   }
 842   case ELF::R_390_PC32: {
 843     int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
 844     assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
 845     writeInt32BE(LocalAddress, Delta);
 846     break;
 847   }
 848   case ELF::R_390_PC64: {
 849     int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
 850     writeInt64BE(LocalAddress, Delta);
 851     break;
 852   }
 853   case ELF::R_390_8:
 854     *LocalAddress = (uint8_t)(Value + Addend);
 855     break;
 856   case ELF::R_390_16:
 857     writeInt16BE(LocalAddress, Value + Addend);
 858     break;
 859   case ELF::R_390_32:
 860     writeInt32BE(LocalAddress, Value + Addend);
 861     break;
 862   case ELF::R_390_64:
 863     writeInt64BE(LocalAddress, Value + Addend);
 864     break;
 865   }
 866 }
 867
 868 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section,
 869                                           uint64_t Offset, uint64_t Value,
 870                                           uint32_t Type, int64_t Addend) {
 871   bool isBE = Arch == Triple::bpfeb;
 872
 873   switch (Type) {
 874   default:
 875     llvm_unreachable("Relocation type not implemented yet!");
 876     break;
 877   case ELF::R_BPF_NONE:
 878     break;
 879   case ELF::R_BPF_64_64: {
 880     write(isBE, Section.getAddressWithOffset(Offset), Value + Addend);
 881     LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
 882                       << format("%p\n", Section.getAddressWithOffset(Offset)));
 883     break;
 884   }
 885   case ELF::R_BPF_64_32: {
 886     Value += Addend;
 887     assert(Value <= UINT32_MAX);
 888     write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value));
 889     LLVM_DEBUG(dbgs() << "Writing " << format("%p", Value) << " at "
 890                       << format("%p\n", Section.getAddressWithOffset(Offset)));
 891     break;
 892   }
 893   }
 894 }
 895
 896 // The target location for the relocation is described by RE.SectionID and
 897 // RE.Offset.  RE.SectionID can be used to find the SectionEntry.  Each
 898 // SectionEntry has three members describing its location.
 899 // SectionEntry::Address is the address at which the section has been loaded
 900 // into memory in the current (host) process.  SectionEntry::LoadAddress is the
 901 // address that the section will have in the target process.
 902 // SectionEntry::ObjAddress is the address of the bits for this section in the
 903 // original emitted object image (also in the current address space).
 904 //
 905 // Relocations will be applied as if the section were loaded at
 906 // SectionEntry::LoadAddress, but they will be applied at an address based
 907 // on SectionEntry::Address.  SectionEntry::ObjAddress will be used to refer to
 908 // Target memory contents if they are required for value calculations.
 909 //
 910 // The Value parameter here is the load address of the symbol for the
 911 // relocation to be applied.  For relocations which refer to symbols in the
 912 // current object Value will be the LoadAddress of the section in which
 913 // the symbol resides (RE.Addend provides additional information about the
 914 // symbol location).  For external symbols, Value will be the address of the
 915 // symbol in the target address space.
 916 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
 917                                        uint64_t Value) {
 918   const SectionEntry &Section = Sections[RE.SectionID];
 919   return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
 920                            RE.SymOffset, RE.SectionID);
 921 }
 922
 923 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
 924                                        uint64_t Offset, uint64_t Value,
 925                                        uint32_t Type, int64_t Addend,
 926                                        uint64_t SymOffset, SID SectionID) {
 927   switch (Arch) {
 928   case Triple::x86_64:
 929     resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
 930     break;
 931   case Triple::x86:
 932     resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
 933                          (uint32_t)(Addend & 0xffffffffL));
 934     break;
 935   case Triple::aarch64:
 936   case Triple::aarch64_be:
 937     resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
 938     break;
 939   case Triple::arm: // Fall through.
 940   case Triple::armeb:
 941   case Triple::thumb:
 942   case Triple::thumbeb:
 943     resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
 944                          (uint32_t)(Addend & 0xffffffffL));
 945     break;
 946   case Triple::ppc:
 947     resolvePPC32Relocation(Section, Offset, Value, Type, Addend);
 948     break;
 949   case Triple::ppc64: // Fall through.
 950   case Triple::ppc64le:
 951     resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
 952     break;
 953   case Triple::systemz:
 954     resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
 955     break;
 956   case Triple::bpfel:
 957   case Triple::bpfeb:
 958     resolveBPFRelocation(Section, Offset, Value, Type, Addend);
 959     break;
 960   default:
 961     llvm_unreachable("Unsupported CPU type!");
 962   }
 963 }
 964
 965 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const {
 966   return (void *)(Sections[SectionID].getObjAddress() + Offset);
 967 }
 968
 969 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) {
 970   RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
 971   if (Value.SymbolName)
 972     addRelocationForSymbol(RE, Value.SymbolName);
 973   else
 974     addRelocationForSection(RE, Value.SectionID);
 975 }
 976
 977 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType,
 978                                                  bool IsLocal) const {
 979   switch (RelType) {
 980   case ELF::R_MICROMIPS_GOT16:
 981     if (IsLocal)
 982       return ELF::R_MICROMIPS_LO16;
 983     break;
 984   case ELF::R_MICROMIPS_HI16:
 985     return ELF::R_MICROMIPS_LO16;
 986   case ELF::R_MIPS_GOT16:
 987     if (IsLocal)
 988       return ELF::R_MIPS_LO16;
 989     break;
 990   case ELF::R_MIPS_HI16:
 991     return ELF::R_MIPS_LO16;
 992   case ELF::R_MIPS_PCHI16:
 993     return ELF::R_MIPS_PCLO16;
 994   default:
 995     break;
 996   }
 997   return ELF::R_MIPS_NONE;
 998 }
 999
1000 // Sometimes we don't need to create thunk for a branch.
1001 // This typically happens when branch target is located
1002 // in the same object file. In such case target is either
1003 // a weak symbol or symbol in a different executable section.
1004 // This function checks if branch target is located in the
1005 // same object file and if distance between source and target
1006 // fits R_AARCH64_CALL26 relocation. If both conditions are
1007 // met, it emits direct jump to the target and returns true.
1008 // Otherwise false is returned and thunk is created.
1009 bool RuntimeDyldELF::resolveAArch64ShortBranch(
1010     unsigned SectionID, relocation_iterator RelI,
1011     const RelocationValueRef &Value) {
1012   uint64_t Address;
1013   if (Value.SymbolName) {
1014     auto Loc = GlobalSymbolTable.find(Value.SymbolName);
1015
1016     // Don't create direct branch for external symbols.
1017     if (Loc == GlobalSymbolTable.end())
1018       return false;
1019
1020     const auto &SymInfo = Loc->second;
1021     Address =
1022         uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset(
1023             SymInfo.getOffset()));
1024   } else {
1025     Address = uint64_t(Sections[Value.SectionID].getLoadAddress());
1026   }
1027   uint64_t Offset = RelI->getOffset();
1028   uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset);
1029
1030   // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27
1031   // If distance between source and target is out of range then we should
1032   // create thunk.
1033   if (!isInt<28>(Address + Value.Addend - SourceAddress))
1034     return false;
1035
1036   resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(),
1037                     Value.Addend);
1038
1039   return true;
1040 }
1041
1042 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID,
1043                                           const RelocationValueRef &Value,
1044                                           relocation_iterator RelI,
1045                                           StubMap &Stubs) {
1046
1047   LLVM_DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
1048   SectionEntry &Section = Sections[SectionID];
1049
1050   uint64_t Offset = RelI->getOffset();
1051   unsigned RelType = RelI->getType();
1052   // Look for an existing stub.
1053   StubMap::const_iterator i = Stubs.find(Value);
1054   if (i != Stubs.end()) {
1055     resolveRelocation(Section, Offset,
1056                       (uint64_t)Section.getAddressWithOffset(i->second),
1057                       RelType, 0);
1058     LLVM_DEBUG(dbgs() << " Stub function found\n");
1059   } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) {
1060     // Create a new stub function.
1061     LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1062     Stubs[Value] = Section.getStubOffset();
1063     uint8_t *StubTargetAddr = createStubFunction(
1064         Section.getAddressWithOffset(Section.getStubOffset()));
1065
1066     RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(),
1067                               ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
1068     RelocationEntry REmovk_g2(SectionID,
1069                               StubTargetAddr - Section.getAddress() + 4,
1070                               ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
1071     RelocationEntry REmovk_g1(SectionID,
1072                               StubTargetAddr - Section.getAddress() + 8,
1073                               ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
1074     RelocationEntry REmovk_g0(SectionID,
1075                               StubTargetAddr - Section.getAddress() + 12,
1076                               ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1077
1078     if (Value.SymbolName) {
1079       addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1080       addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1081       addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1082       addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1083     } else {
1084       addRelocationForSection(REmovz_g3, Value.SectionID);
1085       addRelocationForSection(REmovk_g2, Value.SectionID);
1086       addRelocationForSection(REmovk_g1, Value.SectionID);
1087       addRelocationForSection(REmovk_g0, Value.SectionID);
1088     }
1089     resolveRelocation(Section, Offset,
1090                       reinterpret_cast<uint64_t>(Section.getAddressWithOffset(
1091                           Section.getStubOffset())),
1092                       RelType, 0);
1093     Section.advanceStubOffset(getMaxStubSize());
1094   }
1095 }
1096
1097 Expected<relocation_iterator>
1098 RuntimeDyldELF::processRelocationRef(
1099     unsigned SectionID, relocation_iterator RelI, const ObjectFile &O,
1100     ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) {
1101   const auto &Obj = cast<ELFObjectFileBase>(O);
1102   uint64_t RelType = RelI->getType();
1103   int64_t Addend = 0;
1104   if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend())
1105     Addend = *AddendOrErr;
1106   else
1107     consumeError(AddendOrErr.takeError());
1108   elf_symbol_iterator Symbol = RelI->getSymbol();
1109
1110   // Obtain the symbol name which is referenced in the relocation
1111   StringRef TargetName;
1112   if (Symbol != Obj.symbol_end()) {
1113     if (auto TargetNameOrErr = Symbol->getName())
1114       TargetName = *TargetNameOrErr;
1115     else
1116       return TargetNameOrErr.takeError();
1117   }
1118   LLVM_DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
1119                     << " TargetName: " << TargetName << "\n");
1120   RelocationValueRef Value;
1121   // First search for the symbol in the local symbol table
1122   SymbolRef::Type SymType = SymbolRef::ST_Unknown;
1123
1124   // Search for the symbol in the global symbol table
1125   RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end();
1126   if (Symbol != Obj.symbol_end()) {
1127     gsi = GlobalSymbolTable.find(TargetName.data());
1128     Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType();
1129     if (!SymTypeOrErr) {
1130       std::string Buf;
1131       raw_string_ostream OS(Buf);
1132       logAllUnhandledErrors(SymTypeOrErr.takeError(), OS);
1133       OS.flush();
1134       report_fatal_error(Buf);
1135     }
1136     SymType = *SymTypeOrErr;
1137   }
1138   if (gsi != GlobalSymbolTable.end()) {
1139     const auto &SymInfo = gsi->second;
1140     Value.SectionID = SymInfo.getSectionID();
1141     Value.Offset = SymInfo.getOffset();
1142     Value.Addend = SymInfo.getOffset() + Addend;
1143   } else {
1144     switch (SymType) {
1145     case SymbolRef::ST_Debug: {
1146       // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
1147       // and can be changed by another developers. Maybe best way is add
1148       // a new symbol type ST_Section to SymbolRef and use it.
1149       auto SectionOrErr = Symbol->getSection();
1150       if (!SectionOrErr) {
1151         std::string Buf;
1152         raw_string_ostream OS(Buf);
1153         logAllUnhandledErrors(SectionOrErr.takeError(), OS);
1154         OS.flush();
1155         report_fatal_error(Buf);
1156       }
1157       section_iterator si = *SectionOrErr;
1158       if (si == Obj.section_end())
1159         llvm_unreachable("Symbol section not found, bad object file format!");
1160       LLVM_DEBUG(dbgs() << "\t\tThis is section symbol\n");
1161       bool isCode = si->isText();
1162       if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode,
1163                                                   ObjSectionToID))
1164         Value.SectionID = *SectionIDOrErr;
1165       else
1166         return SectionIDOrErr.takeError();
1167       Value.Addend = Addend;
1168       break;
1169     }
1170     case SymbolRef::ST_Data:
1171     case SymbolRef::ST_Function:
1172     case SymbolRef::ST_Unknown: {
1173       Value.SymbolName = TargetName.data();
1174       Value.Addend = Addend;
1175
1176       // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
1177       // will manifest here as a NULL symbol name.
1178       // We can set this as a valid (but empty) symbol name, and rely
1179       // on addRelocationForSymbol to handle this.
1180       if (!Value.SymbolName)
1181         Value.SymbolName = "";
1182       break;
1183     }
1184     default:
1185       llvm_unreachable("Unresolved symbol type!");
1186       break;
1187     }
1188   }
1189
1190   uint64_t Offset = RelI->getOffset();
1191
1192   LLVM_DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
1193                     << "\n");
1194   if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) {
1195     if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) {
1196       resolveAArch64Branch(SectionID, Value, RelI, Stubs);
1197     } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) {
1198       // Craete new GOT entry or find existing one. If GOT entry is
1199       // to be created, then we also emit ABS64 relocation for it.
1200       uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1201       resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1202                                  ELF::R_AARCH64_ADR_PREL_PG_HI21);
1203
1204     } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) {
1205       uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64);
1206       resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1207                                  ELF::R_AARCH64_LDST64_ABS_LO12_NC);
1208     } else {
1209       processSimpleRelocation(SectionID, Offset, RelType, Value);
1210     }
1211   } else if (Arch == Triple::arm) {
1212     if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1213       RelType == ELF::R_ARM_JUMP24) {
1214       // This is an ARM branch relocation, need to use a stub function.
1215       LLVM_DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n");
1216       SectionEntry &Section = Sections[SectionID];
1217
1218       // Look for an existing stub.
1219       StubMap::const_iterator i = Stubs.find(Value);
1220       if (i != Stubs.end()) {
1221         resolveRelocation(
1222             Section, Offset,
1223             reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)),
1224             RelType, 0);
1225         LLVM_DEBUG(dbgs() << " Stub function found\n");
1226       } else {
1227         // Create a new stub function.
1228         LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1229         Stubs[Value] = Section.getStubOffset();
1230         uint8_t *StubTargetAddr = createStubFunction(
1231             Section.getAddressWithOffset(Section.getStubOffset()));
1232         RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1233                            ELF::R_ARM_ABS32, Value.Addend);
1234         if (Value.SymbolName)
1235           addRelocationForSymbol(RE, Value.SymbolName);
1236         else
1237           addRelocationForSection(RE, Value.SectionID);
1238
1239         resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1240                                                Section.getAddressWithOffset(
1241                                                    Section.getStubOffset())),
1242                           RelType, 0);
1243         Section.advanceStubOffset(getMaxStubSize());
1244       }
1245     } else {
1246       uint32_t *Placeholder =
1247         reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset));
1248       if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 ||
1249           RelType == ELF::R_ARM_ABS32) {
1250         Value.Addend += *Placeholder;
1251       } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) {
1252         // See ELF for ARM documentation
1253         Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12));
1254       }
1255       processSimpleRelocation(SectionID, Offset, RelType, Value);
1256     }
1257   } else if (IsMipsO32ABI) {
1258     uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
1259         computePlaceholderAddress(SectionID, Offset));
1260     uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
1261     if (RelType == ELF::R_MIPS_26) {
1262       // This is an Mips branch relocation, need to use a stub function.
1263       LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1264       SectionEntry &Section = Sections[SectionID];
1265
1266       // Extract the addend from the instruction.
1267       // We shift up by two since the Value will be down shifted again
1268       // when applying the relocation.
1269       uint32_t Addend = (Opcode & 0x03ffffff) << 2;
1270
1271       Value.Addend += Addend;
1272
1273       //  Look up for existing stub.
1274       StubMap::const_iterator i = Stubs.find(Value);
1275       if (i != Stubs.end()) {
1276         RelocationEntry RE(SectionID, Offset, RelType, i->second);
1277         addRelocationForSection(RE, SectionID);
1278         LLVM_DEBUG(dbgs() << " Stub function found\n");
1279       } else {
1280         // Create a new stub function.
1281         LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1282         Stubs[Value] = Section.getStubOffset();
1283
1284         unsigned AbiVariant = Obj.getPlatformFlags();
1285
1286         uint8_t *StubTargetAddr = createStubFunction(
1287             Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1288
1289         // Creating Hi and Lo relocations for the filled stub instructions.
1290         RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1291                              ELF::R_MIPS_HI16, Value.Addend);
1292         RelocationEntry RELo(SectionID,
1293                              StubTargetAddr - Section.getAddress() + 4,
1294                              ELF::R_MIPS_LO16, Value.Addend);
1295
1296         if (Value.SymbolName) {
1297           addRelocationForSymbol(REHi, Value.SymbolName);
1298           addRelocationForSymbol(RELo, Value.SymbolName);
1299         } else {
1300           addRelocationForSection(REHi, Value.SectionID);
1301           addRelocationForSection(RELo, Value.SectionID);
1302         }
1303
1304         RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1305         addRelocationForSection(RE, SectionID);
1306         Section.advanceStubOffset(getMaxStubSize());
1307       }
1308     } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) {
1309       int64_t Addend = (Opcode & 0x0000ffff) << 16;
1310       RelocationEntry RE(SectionID, Offset, RelType, Addend);
1311       PendingRelocs.push_back(std::make_pair(Value, RE));
1312     } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) {
1313       int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff);
1314       for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) {
1315         const RelocationValueRef &MatchingValue = I->first;
1316         RelocationEntry &Reloc = I->second;
1317         if (MatchingValue == Value &&
1318             RelType == getMatchingLoRelocation(Reloc.RelType) &&
1319             SectionID == Reloc.SectionID) {
1320           Reloc.Addend += Addend;
1321           if (Value.SymbolName)
1322             addRelocationForSymbol(Reloc, Value.SymbolName);
1323           else
1324             addRelocationForSection(Reloc, Value.SectionID);
1325           I = PendingRelocs.erase(I);
1326         } else
1327           ++I;
1328       }
1329       RelocationEntry RE(SectionID, Offset, RelType, Addend);
1330       if (Value.SymbolName)
1331         addRelocationForSymbol(RE, Value.SymbolName);
1332       else
1333         addRelocationForSection(RE, Value.SectionID);
1334     } else {
1335       if (RelType == ELF::R_MIPS_32)
1336         Value.Addend += Opcode;
1337       else if (RelType == ELF::R_MIPS_PC16)
1338         Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2);
1339       else if (RelType == ELF::R_MIPS_PC19_S2)
1340         Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2);
1341       else if (RelType == ELF::R_MIPS_PC21_S2)
1342         Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2);
1343       else if (RelType == ELF::R_MIPS_PC26_S2)
1344         Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2);
1345       processSimpleRelocation(SectionID, Offset, RelType, Value);
1346     }
1347   } else if (IsMipsN32ABI || IsMipsN64ABI) {
1348     uint32_t r_type = RelType & 0xff;
1349     RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1350     if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
1351         || r_type == ELF::R_MIPS_GOT_DISP) {
1352       StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
1353       if (i != GOTSymbolOffsets.end())
1354         RE.SymOffset = i->second;
1355       else {
1356         RE.SymOffset = allocateGOTEntries(1);
1357         GOTSymbolOffsets[TargetName] = RE.SymOffset;
1358       }
1359       if (Value.SymbolName)
1360         addRelocationForSymbol(RE, Value.SymbolName);
1361       else
1362         addRelocationForSection(RE, Value.SectionID);
1363     } else if (RelType == ELF::R_MIPS_26) {
1364       // This is an Mips branch relocation, need to use a stub function.
1365       LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1366       SectionEntry &Section = Sections[SectionID];
1367
1368       //  Look up for existing stub.
1369       StubMap::const_iterator i = Stubs.find(Value);
1370       if (i != Stubs.end()) {
1371         RelocationEntry RE(SectionID, Offset, RelType, i->second);
1372         addRelocationForSection(RE, SectionID);
1373         LLVM_DEBUG(dbgs() << " Stub function found\n");
1374       } else {
1375         // Create a new stub function.
1376         LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1377         Stubs[Value] = Section.getStubOffset();
1378
1379         unsigned AbiVariant = Obj.getPlatformFlags();
1380
1381         uint8_t *StubTargetAddr = createStubFunction(
1382             Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1383
1384         if (IsMipsN32ABI) {
1385           // Creating Hi and Lo relocations for the filled stub instructions.
1386           RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1387                                ELF::R_MIPS_HI16, Value.Addend);
1388           RelocationEntry RELo(SectionID,
1389                                StubTargetAddr - Section.getAddress() + 4,
1390                                ELF::R_MIPS_LO16, Value.Addend);
1391           if (Value.SymbolName) {
1392             addRelocationForSymbol(REHi, Value.SymbolName);
1393             addRelocationForSymbol(RELo, Value.SymbolName);
1394           } else {
1395             addRelocationForSection(REHi, Value.SectionID);
1396             addRelocationForSection(RELo, Value.SectionID);
1397           }
1398         } else {
1399           // Creating Highest, Higher, Hi and Lo relocations for the filled stub
1400           // instructions.
1401           RelocationEntry REHighest(SectionID,
1402                                     StubTargetAddr - Section.getAddress(),
1403                                     ELF::R_MIPS_HIGHEST, Value.Addend);
1404           RelocationEntry REHigher(SectionID,
1405                                    StubTargetAddr - Section.getAddress() + 4,
1406                                    ELF::R_MIPS_HIGHER, Value.Addend);
1407           RelocationEntry REHi(SectionID,
1408                                StubTargetAddr - Section.getAddress() + 12,
1409                                ELF::R_MIPS_HI16, Value.Addend);
1410           RelocationEntry RELo(SectionID,
1411                                StubTargetAddr - Section.getAddress() + 20,
1412                                ELF::R_MIPS_LO16, Value.Addend);
1413           if (Value.SymbolName) {
1414             addRelocationForSymbol(REHighest, Value.SymbolName);
1415             addRelocationForSymbol(REHigher, Value.SymbolName);
1416             addRelocationForSymbol(REHi, Value.SymbolName);
1417             addRelocationForSymbol(RELo, Value.SymbolName);
1418           } else {
1419             addRelocationForSection(REHighest, Value.SectionID);
1420             addRelocationForSection(REHigher, Value.SectionID);
1421             addRelocationForSection(REHi, Value.SectionID);
1422             addRelocationForSection(RELo, Value.SectionID);
1423           }
1424         }
1425         RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1426         addRelocationForSection(RE, SectionID);
1427         Section.advanceStubOffset(getMaxStubSize());
1428       }
1429     } else {
1430       processSimpleRelocation(SectionID, Offset, RelType, Value);
1431     }
1432
1433   } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1434     if (RelType == ELF::R_PPC64_REL24) {
1435       // Determine ABI variant in use for this object.
1436       unsigned AbiVariant = Obj.getPlatformFlags();
1437       AbiVariant &= ELF::EF_PPC64_ABI;
1438       // A PPC branch relocation will need a stub function if the target is
1439       // an external symbol (either Value.SymbolName is set, or SymType is
1440       // Symbol::ST_Unknown) or if the target address is not within the
1441       // signed 24-bits branch address.
1442       SectionEntry &Section = Sections[SectionID];
1443       uint8_t *Target = Section.getAddressWithOffset(Offset);
1444       bool RangeOverflow = false;
1445       bool IsExtern = Value.SymbolName || SymType == SymbolRef::ST_Unknown;
1446       if (!IsExtern) {
1447         if (AbiVariant != 2) {
1448           // In the ELFv1 ABI, a function call may point to the .opd entry,
1449           // so the final symbol value is calculated based on the relocation
1450           // values in the .opd section.
1451           if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value))
1452             return std::move(Err);
1453         } else {
1454           // In the ELFv2 ABI, a function symbol may provide a local entry
1455           // point, which must be used for direct calls.
1456           if (Value.SectionID == SectionID){
1457             uint8_t SymOther = Symbol->getOther();
1458             Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther);
1459           }
1460         }
1461         uint8_t *RelocTarget =
1462             Sections[Value.SectionID].getAddressWithOffset(Value.Addend);
1463         int64_t delta = static_cast<int64_t>(Target - RelocTarget);
1464         // If it is within 26-bits branch range, just set the branch target
1465         if (SignExtend64<26>(delta) != delta) {
1466           RangeOverflow = true;
1467         } else if ((AbiVariant != 2) ||
1468                    (AbiVariant == 2  && Value.SectionID == SectionID)) {
1469           RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1470           addRelocationForSection(RE, Value.SectionID);
1471         }
1472       }
1473       if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID) ||
1474           RangeOverflow) {
1475         // It is an external symbol (either Value.SymbolName is set, or
1476         // SymType is SymbolRef::ST_Unknown) or out of range.
1477         StubMap::const_iterator i = Stubs.find(Value);
1478         if (i != Stubs.end()) {
1479           // Symbol function stub already created, just relocate to it
1480           resolveRelocation(Section, Offset,
1481                             reinterpret_cast<uint64_t>(
1482                                 Section.getAddressWithOffset(i->second)),
1483                             RelType, 0);
1484           LLVM_DEBUG(dbgs() << " Stub function found\n");
1485         } else {
1486           // Create a new stub function.
1487           LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1488           Stubs[Value] = Section.getStubOffset();
1489           uint8_t *StubTargetAddr = createStubFunction(
1490               Section.getAddressWithOffset(Section.getStubOffset()),
1491               AbiVariant);
1492           RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1493                              ELF::R_PPC64_ADDR64, Value.Addend);
1494
1495           // Generates the 64-bits address loads as exemplified in section
1496           // 4.5.1 in PPC64 ELF ABI.  Note that the relocations need to
1497           // apply to the low part of the instructions, so we have to update
1498           // the offset according to the target endianness.
1499           uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress();
1500           if (!IsTargetLittleEndian)
1501             StubRelocOffset += 2;
1502
1503           RelocationEntry REhst(SectionID, StubRelocOffset + 0,
1504                                 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1505           RelocationEntry REhr(SectionID, StubRelocOffset + 4,
1506                                ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1507           RelocationEntry REh(SectionID, StubRelocOffset + 12,
1508                               ELF::R_PPC64_ADDR16_HI, Value.Addend);
1509           RelocationEntry REl(SectionID, StubRelocOffset + 16,
1510                               ELF::R_PPC64_ADDR16_LO, Value.Addend);
1511
1512           if (Value.SymbolName) {
1513             addRelocationForSymbol(REhst, Value.SymbolName);
1514             addRelocationForSymbol(REhr, Value.SymbolName);
1515             addRelocationForSymbol(REh, Value.SymbolName);
1516             addRelocationForSymbol(REl, Value.SymbolName);
1517           } else {
1518             addRelocationForSection(REhst, Value.SectionID);
1519             addRelocationForSection(REhr, Value.SectionID);
1520             addRelocationForSection(REh, Value.SectionID);
1521             addRelocationForSection(REl, Value.SectionID);
1522           }
1523
1524           resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1525                                                  Section.getAddressWithOffset(
1526                                                      Section.getStubOffset())),
1527                             RelType, 0);
1528           Section.advanceStubOffset(getMaxStubSize());
1529         }
1530         if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID)) {
1531           // Restore the TOC for external calls
1532           if (AbiVariant == 2)
1533             writeInt32BE(Target + 4, 0xE8410018); // ld r2,24(r1)
1534           else
1535             writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1536         }
1537       }
1538     } else if (RelType == ELF::R_PPC64_TOC16 ||
1539                RelType == ELF::R_PPC64_TOC16_DS ||
1540                RelType == ELF::R_PPC64_TOC16_LO ||
1541                RelType == ELF::R_PPC64_TOC16_LO_DS ||
1542                RelType == ELF::R_PPC64_TOC16_HI ||
1543                RelType == ELF::R_PPC64_TOC16_HA) {
1544       // These relocations are supposed to subtract the TOC address from
1545       // the final value.  This does not fit cleanly into the RuntimeDyld
1546       // scheme, since there may be *two* sections involved in determining
1547       // the relocation value (the section of the symbol referred to by the
1548       // relocation, and the TOC section associated with the current module).
1549       //
1550       // Fortunately, these relocations are currently only ever generated
1551       // referring to symbols that themselves reside in the TOC, which means
1552       // that the two sections are actually the same.  Thus they cancel out
1553       // and we can immediately resolve the relocation right now.
1554       switch (RelType) {
1555       case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break;
1556       case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break;
1557       case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break;
1558       case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break;
1559       case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break;
1560       case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break;
1561       default: llvm_unreachable("Wrong relocation type.");
1562       }
1563
1564       RelocationValueRef TOCValue;
1565       if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue))
1566         return std::move(Err);
1567       if (Value.SymbolName || Value.SectionID != TOCValue.SectionID)
1568         llvm_unreachable("Unsupported TOC relocation.");
1569       Value.Addend -= TOCValue.Addend;
1570       resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0);
1571     } else {
1572       // There are two ways to refer to the TOC address directly: either
1573       // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are
1574       // ignored), or via any relocation that refers to the magic ".TOC."
1575       // symbols (in which case the addend is respected).
1576       if (RelType == ELF::R_PPC64_TOC) {
1577         RelType = ELF::R_PPC64_ADDR64;
1578         if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1579           return std::move(Err);
1580       } else if (TargetName == ".TOC.") {
1581         if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1582           return std::move(Err);
1583         Value.Addend += Addend;
1584       }
1585
1586       RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1587
1588       if (Value.SymbolName)
1589         addRelocationForSymbol(RE, Value.SymbolName);
1590       else
1591         addRelocationForSection(RE, Value.SectionID);
1592     }
1593   } else if (Arch == Triple::systemz &&
1594              (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1595     // Create function stubs for both PLT and GOT references, regardless of
1596     // whether the GOT reference is to data or code.  The stub contains the
1597     // full address of the symbol, as needed by GOT references, and the
1598     // executable part only adds an overhead of 8 bytes.
1599     //
1600     // We could try to conserve space by allocating the code and data
1601     // parts of the stub separately.  However, as things stand, we allocate
1602     // a stub for every relocation, so using a GOT in JIT code should be
1603     // no less space efficient than using an explicit constant pool.
1604     LLVM_DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1605     SectionEntry &Section = Sections[SectionID];
1606
1607     // Look for an existing stub.
1608     StubMap::const_iterator i = Stubs.find(Value);
1609     uintptr_t StubAddress;
1610     if (i != Stubs.end()) {
1611       StubAddress = uintptr_t(Section.getAddressWithOffset(i->second));
1612       LLVM_DEBUG(dbgs() << " Stub function found\n");
1613     } else {
1614       // Create a new stub function.
1615       LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1616
1617       uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1618       uintptr_t StubAlignment = getStubAlignment();
1619       StubAddress =
1620           (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1621           -StubAlignment;
1622       unsigned StubOffset = StubAddress - BaseAddress;
1623
1624       Stubs[Value] = StubOffset;
1625       createStubFunction((uint8_t *)StubAddress);
1626       RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1627                          Value.Offset);
1628       if (Value.SymbolName)
1629         addRelocationForSymbol(RE, Value.SymbolName);
1630       else
1631         addRelocationForSection(RE, Value.SectionID);
1632       Section.advanceStubOffset(getMaxStubSize());
1633     }
1634
1635     if (RelType == ELF::R_390_GOTENT)
1636       resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1637                         Addend);
1638     else
1639       resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1640   } else if (Arch == Triple::x86_64) {
1641     if (RelType == ELF::R_X86_64_PLT32) {
1642       // The way the PLT relocations normally work is that the linker allocates
1643       // the
1644       // PLT and this relocation makes a PC-relative call into the PLT.  The PLT
1645       // entry will then jump to an address provided by the GOT.  On first call,
1646       // the
1647       // GOT address will point back into PLT code that resolves the symbol. After
1648       // the first call, the GOT entry points to the actual function.
1649       //
1650       // For local functions we're ignoring all of that here and just replacing
1651       // the PLT32 relocation type with PC32, which will translate the relocation
1652       // into a PC-relative call directly to the function. For external symbols we
1653       // can't be sure the function will be within 2^32 bytes of the call site, so
1654       // we need to create a stub, which calls into the GOT.  This case is
1655       // equivalent to the usual PLT implementation except that we use the stub
1656       // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1657       // rather than allocating a PLT section.
1658       if (Value.SymbolName) {
1659         // This is a call to an external function.
1660         // Look for an existing stub.
1661         SectionEntry &Section = Sections[SectionID];
1662         StubMap::const_iterator i = Stubs.find(Value);
1663         uintptr_t StubAddress;
1664         if (i != Stubs.end()) {
1665           StubAddress = uintptr_t(Section.getAddress()) + i->second;
1666           LLVM_DEBUG(dbgs() << " Stub function found\n");
1667         } else {
1668           // Create a new stub function (equivalent to a PLT entry).
1669           LLVM_DEBUG(dbgs() << " Create a new stub function\n");
1670
1671           uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1672           uintptr_t StubAlignment = getStubAlignment();
1673           StubAddress =
1674               (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1675               -StubAlignment;
1676           unsigned StubOffset = StubAddress - BaseAddress;
1677           Stubs[Value] = StubOffset;
1678           createStubFunction((uint8_t *)StubAddress);
1679
1680           // Bump our stub offset counter
1681           Section.advanceStubOffset(getMaxStubSize());
1682
1683           // Allocate a GOT Entry
1684           uint64_t GOTOffset = allocateGOTEntries(1);
1685
1686           // The load of the GOT address has an addend of -4
1687           resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4,
1688                                      ELF::R_X86_64_PC32);
1689
1690           // Fill in the value of the symbol we're targeting into the GOT
1691           addRelocationForSymbol(
1692               computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64),
1693               Value.SymbolName);
1694         }
1695
1696         // Make the target call a call into the stub table.
1697         resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1698                           Addend);
1699       } else {
1700         RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1701                   Value.Offset);
1702         addRelocationForSection(RE, Value.SectionID);
1703       }
1704     } else if (RelType == ELF::R_X86_64_GOTPCREL ||
1705                RelType == ELF::R_X86_64_GOTPCRELX ||
1706                RelType == ELF::R_X86_64_REX_GOTPCRELX) {
1707       uint64_t GOTOffset = allocateGOTEntries(1);
1708       resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend,
1709                                  ELF::R_X86_64_PC32);
1710
1711       // Fill in the value of the symbol we're targeting into the GOT
1712       RelocationEntry RE =
1713           computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64);
1714       if (Value.SymbolName)
1715         addRelocationForSymbol(RE, Value.SymbolName);
1716       else
1717         addRelocationForSection(RE, Value.SectionID);
1718     } else if (RelType == ELF::R_X86_64_GOT64) {
1719       // Fill in a 64-bit GOT offset.
1720       uint64_t GOTOffset = allocateGOTEntries(1);
1721       resolveRelocation(Sections[SectionID], Offset, GOTOffset,
1722                         ELF::R_X86_64_64, 0);
1723
1724       // Fill in the value of the symbol we're targeting into the GOT
1725       RelocationEntry RE =
1726           computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64);
1727       if (Value.SymbolName)
1728         addRelocationForSymbol(RE, Value.SymbolName);
1729       else
1730         addRelocationForSection(RE, Value.SectionID);
1731     } else if (RelType == ELF::R_X86_64_GOTPC64) {
1732       // Materialize the address of the base of the GOT relative to the PC.
1733       // This doesn't create a GOT entry, but it does mean we need a GOT
1734       // section.
1735       (void)allocateGOTEntries(0);
1736       resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC64);
1737     } else if (RelType == ELF::R_X86_64_GOTOFF64) {
1738       // GOTOFF relocations ultimately require a section difference relocation.
1739       (void)allocateGOTEntries(0);
1740       processSimpleRelocation(SectionID, Offset, RelType, Value);
1741     } else if (RelType == ELF::R_X86_64_PC32) {
1742       Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1743       processSimpleRelocation(SectionID, Offset, RelType, Value);
1744     } else if (RelType == ELF::R_X86_64_PC64) {
1745       Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset));
1746       processSimpleRelocation(SectionID, Offset, RelType, Value);
1747     } else {
1748       processSimpleRelocation(SectionID, Offset, RelType, Value);
1749     }
1750   } else {
1751     if (Arch == Triple::x86) {
1752       Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1753     }
1754     processSimpleRelocation(SectionID, Offset, RelType, Value);
1755   }
1756   return ++RelI;
1757 }
1758
1759 size_t RuntimeDyldELF::getGOTEntrySize() {
1760   // We don't use the GOT in all of these cases, but it's essentially free
1761   // to put them all here.
1762   size_t Result = 0;
1763   switch (Arch) {
1764   case Triple::x86_64:
1765   case Triple::aarch64:
1766   case Triple::aarch64_be:
1767   case Triple::ppc64:
1768   case Triple::ppc64le:
1769   case Triple::systemz:
1770     Result = sizeof(uint64_t);
1771     break;
1772   case Triple::x86:
1773   case Triple::arm:
1774   case Triple::thumb:
1775     Result = sizeof(uint32_t);
1776     break;
1777   case Triple::mips:
1778   case Triple::mipsel:
1779   case Triple::mips64:
1780   case Triple::mips64el:
1781     if (IsMipsO32ABI || IsMipsN32ABI)
1782       Result = sizeof(uint32_t);
1783     else if (IsMipsN64ABI)
1784       Result = sizeof(uint64_t);
1785     else
1786       llvm_unreachable("Mips ABI not handled");
1787     break;
1788   default:
1789     llvm_unreachable("Unsupported CPU type!");
1790   }
1791   return Result;
1792 }
1793
1794 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) {
1795   if (GOTSectionID == 0) {
1796     GOTSectionID = Sections.size();
1797     // Reserve a section id. We'll allocate the section later
1798     // once we know the total size
1799     Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0));
1800   }
1801   uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
1802   CurrentGOTIndex += no;
1803   return StartOffset;
1804 }
1805
1806 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value,
1807                                              unsigned GOTRelType) {
1808   auto E = GOTOffsetMap.insert({Value, 0});
1809   if (E.second) {
1810     uint64_t GOTOffset = allocateGOTEntries(1);
1811
1812     // Create relocation for newly created GOT entry
1813     RelocationEntry RE =
1814         computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType);
1815     if (Value.SymbolName)
1816       addRelocationForSymbol(RE, Value.SymbolName);
1817     else
1818       addRelocationForSection(RE, Value.SectionID);
1819
1820     E.first->second = GOTOffset;
1821   }
1822
1823   return E.first->second;
1824 }
1825
1826 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID,
1827                                                 uint64_t Offset,
1828                                                 uint64_t GOTOffset,
1829                                                 uint32_t Type) {
1830   // Fill in the relative address of the GOT Entry into the stub
1831   RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset);
1832   addRelocationForSection(GOTRE, GOTSectionID);
1833 }
1834
1835 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset,
1836                                                    uint64_t SymbolOffset,
1837                                                    uint32_t Type) {
1838   return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
1839 }
1840
1841 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj,
1842                                   ObjSectionToIDMap &SectionMap) {
1843   if (IsMipsO32ABI)
1844     if (!PendingRelocs.empty())
1845       return make_error<RuntimeDyldError>("Can't find matching LO16 reloc");
1846
1847   // If necessary, allocate the global offset table
1848   if (GOTSectionID != 0) {
1849     // Allocate memory for the section
1850     size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
1851     uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
1852                                                 GOTSectionID, ".got", false);
1853     if (!Addr)
1854       return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!");
1855
1856     Sections[GOTSectionID] =
1857         SectionEntry(".got", Addr, TotalSize, TotalSize, 0);
1858
1859     // For now, initialize all GOT entries to zero.  We'll fill them in as
1860     // needed when GOT-based relocations are applied.
1861     memset(Addr, 0, TotalSize);
1862     if (IsMipsN32ABI || IsMipsN64ABI) {
1863       // To correctly resolve Mips GOT relocations, we need a mapping from
1864       // object's sections to GOTs.
1865       for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
1866            SI != SE; ++SI) {
1867         if (SI->relocation_begin() != SI->relocation_end()) {
1868           section_iterator RelocatedSection = SI->getRelocatedSection();
1869           ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection);
1870           assert (i != SectionMap.end());
1871           SectionToGOTMap[i->second] = GOTSectionID;
1872         }
1873       }
1874       GOTSymbolOffsets.clear();
1875     }
1876   }
1877
1878   // Look for and record the EH frame section.
1879   ObjSectionToIDMap::iterator i, e;
1880   for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1881     const SectionRef &Section = i->first;
1882     StringRef Name;
1883     Section.getName(Name);
1884     if (Name == ".eh_frame") {
1885       UnregisteredEHFrameSections.push_back(i->second);
1886       break;
1887     }
1888   }
1889
1890   GOTSectionID = 0;
1891   CurrentGOTIndex = 0;
1892
1893   return Error::success();
1894 }
1895
1896 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const {
1897   return Obj.isELF();
1898 }
1899
1900 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const {
1901   unsigned RelTy = R.getType();
1902   if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be)
1903     return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE ||
1904            RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC;
1905
1906   if (Arch == Triple::x86_64)
1907     return RelTy == ELF::R_X86_64_GOTPCREL ||
1908            RelTy == ELF::R_X86_64_GOTPCRELX ||
1909            RelTy == ELF::R_X86_64_GOT64 ||
1910            RelTy == ELF::R_X86_64_REX_GOTPCRELX;
1911   return false;
1912 }
1913
1914 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const {
1915   if (Arch != Triple::x86_64)
1916     return true;  // Conservative answer
1917
1918   switch (R.getType()) {
1919   default:
1920     return true;  // Conservative answer
1921
1922
1923   case ELF::R_X86_64_GOTPCREL:
1924   case ELF::R_X86_64_GOTPCRELX:
1925   case ELF::R_X86_64_REX_GOTPCRELX:
1926   case ELF::R_X86_64_GOTPC64:
1927   case ELF::R_X86_64_GOT64:
1928   case ELF::R_X86_64_GOTOFF64:
1929   case ELF::R_X86_64_PC32:
1930   case ELF::R_X86_64_PC64:
1931   case ELF::R_X86_64_64:
1932     // We know that these reloation types won't need a stub function.  This list
1933     // can be extended as needed.
1934     return false;
1935   }
1936 }
1937
1938 } // namespace llvm