lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

   1 //===-- RuntimeDyldELF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Implementation of ELF support for the MC-JIT runtime dynamic linker.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #define DEBUG_TYPE "dyld"
  15 #include "RuntimeDyldELF.h"
  16 #include "JITRegistrar.h"
  17 #include "ObjectImageCommon.h"
  18 #include "llvm/ADT/IntervalMap.h"
  19 #include "llvm/ADT/OwningPtr.h"
  20 #include "llvm/ADT/STLExtras.h"
  21 #include "llvm/ADT/StringRef.h"
  22 #include "llvm/ADT/Triple.h"
  23 #include "llvm/ExecutionEngine/ObjectBuffer.h"
  24 #include "llvm/ExecutionEngine/ObjectImage.h"
  25 #include "llvm/Object/ELF.h"
  26 #include "llvm/Object/ObjectFile.h"
  27 #include "llvm/Support/ELF.h"
  28 using namespace llvm;
  29 using namespace llvm::object;
  30
  31 namespace {
  32
  33 static inline
  34 error_code check(error_code Err) {
  35   if (Err) {
  36     report_fatal_error(Err.message());
  37   }
  38   return Err;
  39 }
  40
  41 template<class ELFT>
  42 class DyldELFObject
  43   : public ELFObjectFile<ELFT> {
  44   LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
  45
  46   typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
  47   typedef Elf_Sym_Impl<ELFT> Elf_Sym;
  48   typedef
  49     Elf_Rel_Impl<ELFT, false> Elf_Rel;
  50   typedef
  51     Elf_Rel_Impl<ELFT, true> Elf_Rela;
  52
  53   typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
  54
  55   typedef typename ELFDataTypeTypedefHelper<
  56           ELFT>::value_type addr_type;
  57
  58 public:
  59   DyldELFObject(MemoryBuffer *Wrapper, error_code &ec);
  60
  61   void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
  62   void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr);
  63
  64   // Methods for type inquiry through isa, cast and dyn_cast
  65   static inline bool classof(const Binary *v) {
  66     return (isa<ELFObjectFile<ELFT> >(v)
  67             && classof(cast<ELFObjectFile
  68                 <ELFT> >(v)));
  69   }
  70   static inline bool classof(
  71       const ELFObjectFile<ELFT> *v) {
  72     return v->isDyldType();
  73   }
  74 };
  75
  76 template<class ELFT>
  77 class ELFObjectImage : public ObjectImageCommon {
  78   protected:
  79     DyldELFObject<ELFT> *DyldObj;
  80     bool Registered;
  81
  82   public:
  83     ELFObjectImage(ObjectBuffer *Input,
  84                  DyldELFObject<ELFT> *Obj)
  85     : ObjectImageCommon(Input, Obj),
  86       DyldObj(Obj),
  87       Registered(false) {}
  88
  89     virtual ~ELFObjectImage() {
  90       if (Registered)
  91         deregisterWithDebugger();
  92     }
  93
  94     // Subclasses can override these methods to update the image with loaded
  95     // addresses for sections and common symbols
  96     virtual void updateSectionAddress(const SectionRef &Sec, uint64_t Addr)
  97     {
  98       DyldObj->updateSectionAddress(Sec, Addr);
  99     }
 100
 101     virtual void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr)
 102     {
 103       DyldObj->updateSymbolAddress(Sym, Addr);
 104     }
 105
 106     virtual void registerWithDebugger()
 107     {
 108       JITRegistrar::getGDBRegistrar().registerObject(*Buffer);
 109       Registered = true;
 110     }
 111     virtual void deregisterWithDebugger()
 112     {
 113       JITRegistrar::getGDBRegistrar().deregisterObject(*Buffer);
 114     }
 115 };
 116
 117 // The MemoryBuffer passed into this constructor is just a wrapper around the
 118 // actual memory.  Ultimately, the Binary parent class will take ownership of
 119 // this MemoryBuffer object but not the underlying memory.
 120 template<class ELFT>
 121 DyldELFObject<ELFT>::DyldELFObject(MemoryBuffer *Wrapper, error_code &ec)
 122   : ELFObjectFile<ELFT>(Wrapper, ec) {
 123   this->isDyldELFObject = true;
 124 }
 125
 126 template<class ELFT>
 127 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
 128                                                uint64_t Addr) {
 129   DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
 130   Elf_Shdr *shdr = const_cast<Elf_Shdr*>(
 131                           reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
 132
 133   // This assumes the address passed in matches the target address bitness
 134   // The template-based type cast handles everything else.
 135   shdr->sh_addr = static_cast<addr_type>(Addr);
 136 }
 137
 138 template<class ELFT>
 139 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
 140                                               uint64_t Addr) {
 141
 142   Elf_Sym *sym = const_cast<Elf_Sym*>(
 143     ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
 144
 145   // This assumes the address passed in matches the target address bitness
 146   // The template-based type cast handles everything else.
 147   sym->st_value = static_cast<addr_type>(Addr);
 148 }
 149
 150 } // namespace
 151
 152 namespace llvm {
 153
 154 ObjectImage *RuntimeDyldELF::createObjectImage(ObjectBuffer *Buffer) {
 155   if (Buffer->getBufferSize() < ELF::EI_NIDENT)
 156     llvm_unreachable("Unexpected ELF object size");
 157   std::pair<unsigned char, unsigned char> Ident = std::make_pair(
 158                          (uint8_t)Buffer->getBufferStart()[ELF::EI_CLASS],
 159                          (uint8_t)Buffer->getBufferStart()[ELF::EI_DATA]);
 160   error_code ec;
 161
 162   if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) {
 163     DyldELFObject<ELFType<support::little, 4, false> > *Obj =
 164       new DyldELFObject<ELFType<support::little, 4, false> >(
 165         Buffer->getMemBuffer(), ec);
 166     return new ELFObjectImage<ELFType<support::little, 4, false> >(Buffer, Obj);
 167   }
 168   else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB) {
 169     DyldELFObject<ELFType<support::big, 4, false> > *Obj =
 170       new DyldELFObject<ELFType<support::big, 4, false> >(
 171         Buffer->getMemBuffer(), ec);
 172     return new ELFObjectImage<ELFType<support::big, 4, false> >(Buffer, Obj);
 173   }
 174   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB) {
 175     DyldELFObject<ELFType<support::big, 8, true> > *Obj =
 176       new DyldELFObject<ELFType<support::big, 8, true> >(
 177         Buffer->getMemBuffer(), ec);
 178     return new ELFObjectImage<ELFType<support::big, 8, true> >(Buffer, Obj);
 179   }
 180   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
 181     DyldELFObject<ELFType<support::little, 8, true> > *Obj =
 182       new DyldELFObject<ELFType<support::little, 8, true> >(
 183         Buffer->getMemBuffer(), ec);
 184     return new ELFObjectImage<ELFType<support::little, 8, true> >(Buffer, Obj);
 185   }
 186   else
 187     llvm_unreachable("Unexpected ELF format");
 188 }
 189
 190 RuntimeDyldELF::~RuntimeDyldELF() {
 191 }
 192
 193 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
 194                                              uint64_t Offset,
 195                                              uint64_t Value,
 196                                              uint32_t Type,
 197                                              int64_t Addend) {
 198   switch (Type) {
 199   default:
 200     llvm_unreachable("Relocation type not implemented yet!");
 201   break;
 202   case ELF::R_X86_64_64: {
 203     uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset);
 204     *Target = Value + Addend;
 205     DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend))
 206                  << " at " << format("%p\n",Target));
 207     break;
 208   }
 209   case ELF::R_X86_64_32:
 210   case ELF::R_X86_64_32S: {
 211     Value += Addend;
 212     assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
 213            (Type == ELF::R_X86_64_32S &&
 214              ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
 215     uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
 216     uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
 217     *Target = TruncatedAddr;
 218     DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr)
 219                  << " at " << format("%p\n",Target));
 220     break;
 221   }
 222   case ELF::R_X86_64_PC32: {
 223     // Get the placeholder value from the generated object since
 224     // a previous relocation attempt may have overwritten the loaded version
 225     uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
 226                                                                    + Offset);
 227     uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
 228     uint64_t  FinalAddress = Section.LoadAddress + Offset;
 229     int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
 230     assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
 231     int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
 232     *Target = TruncOffset;
 233     break;
 234   }
 235   }
 236 }
 237
 238 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
 239                                           uint64_t Offset,
 240                                           uint32_t Value,
 241                                           uint32_t Type,
 242                                           int32_t Addend) {
 243   switch (Type) {
 244   case ELF::R_386_32: {
 245     // Get the placeholder value from the generated object since
 246     // a previous relocation attempt may have overwritten the loaded version
 247     uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
 248                                                                    + Offset);
 249     uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
 250     *Target = *Placeholder + Value + Addend;
 251     break;
 252   }
 253   case ELF::R_386_PC32: {
 254     // Get the placeholder value from the generated object since
 255     // a previous relocation attempt may have overwritten the loaded version
 256     uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
 257                                                                    + Offset);
 258     uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
 259     uint32_t  FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
 260     uint32_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
 261     *Target = RealOffset;
 262     break;
 263     }
 264     default:
 265       // There are other relocation types, but it appears these are the
 266       // only ones currently used by the LLVM ELF object writer
 267       llvm_unreachable("Relocation type not implemented yet!");
 268       break;
 269   }
 270 }
 271
 272 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
 273                                           uint64_t Offset,
 274                                           uint32_t Value,
 275                                           uint32_t Type,
 276                                           int32_t Addend) {
 277   // TODO: Add Thumb relocations.
 278   uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
 279   uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
 280   Value += Addend;
 281
 282   DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
 283                << Section.Address + Offset
 284                << " FinalAddress: " << format("%p",FinalAddress)
 285                << " Value: " << format("%x",Value)
 286                << " Type: " << format("%x",Type)
 287                << " Addend: " << format("%x",Addend)
 288                << "\n");
 289
 290   switch(Type) {
 291   default:
 292     llvm_unreachable("Not implemented relocation type!");
 293
 294   // Write a 32bit value to relocation address, taking into account the
 295   // implicit addend encoded in the target.
 296   case ELF::R_ARM_TARGET1 :
 297   case ELF::R_ARM_ABS32 :
 298     *TargetPtr += Value;
 299     break;
 300
 301   // Write first 16 bit of 32 bit value to the mov instruction.
 302   // Last 4 bit should be shifted.
 303   case ELF::R_ARM_MOVW_ABS_NC :
 304     // We are not expecting any other addend in the relocation address.
 305     // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2
 306     // non-contiguous fields.
 307     assert((*TargetPtr & 0x000F0FFF) == 0);
 308     Value = Value & 0xFFFF;
 309     *TargetPtr |= Value & 0xFFF;
 310     *TargetPtr |= ((Value >> 12) & 0xF) << 16;
 311     break;
 312
 313   // Write last 16 bit of 32 bit value to the mov instruction.
 314   // Last 4 bit should be shifted.
 315   case ELF::R_ARM_MOVT_ABS :
 316     // We are not expecting any other addend in the relocation address.
 317     // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC.
 318     assert((*TargetPtr & 0x000F0FFF) == 0);
 319     Value = (Value >> 16) & 0xFFFF;
 320     *TargetPtr |= Value & 0xFFF;
 321     *TargetPtr |= ((Value >> 12) & 0xF) << 16;
 322     break;
 323
 324   // Write 24 bit relative value to the branch instruction.
 325   case ELF::R_ARM_PC24 :    // Fall through.
 326   case ELF::R_ARM_CALL :    // Fall through.
 327   case ELF::R_ARM_JUMP24 :
 328     int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
 329     RelValue = (RelValue & 0x03FFFFFC) >> 2;
 330     *TargetPtr &= 0xFF000000;
 331     *TargetPtr |= RelValue;
 332     break;
 333   }
 334 }
 335
 336 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
 337                                            uint64_t Offset,
 338                                            uint32_t Value,
 339                                            uint32_t Type,
 340                                            int32_t Addend) {
 341   uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
 342   Value += Addend;
 343
 344   DEBUG(dbgs() << "resolveMipselocation, LocalAddress: "
 345                << Section.Address + Offset
 346                << " FinalAddress: "
 347                << format("%p",Section.LoadAddress + Offset)
 348                << " Value: " << format("%x",Value)
 349                << " Type: " << format("%x",Type)
 350                << " Addend: " << format("%x",Addend)
 351                << "\n");
 352
 353   switch(Type) {
 354   default:
 355     llvm_unreachable("Not implemented relocation type!");
 356     break;
 357   case ELF::R_MIPS_32:
 358     *TargetPtr = Value + (*TargetPtr);
 359     break;
 360   case ELF::R_MIPS_26:
 361     *TargetPtr = ((*TargetPtr) & 0xfc000000) | (( Value & 0x0fffffff) >> 2);
 362     break;
 363   case ELF::R_MIPS_HI16:
 364     // Get the higher 16-bits. Also add 1 if bit 15 is 1.
 365     Value += ((*TargetPtr) & 0x0000ffff) << 16;
 366     *TargetPtr = ((*TargetPtr) & 0xffff0000) |
 367                  (((Value + 0x8000) >> 16) & 0xffff);
 368     break;
 369    case ELF::R_MIPS_LO16:
 370     Value += ((*TargetPtr) & 0x0000ffff);
 371     *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
 372     break;
 373    }
 374 }
 375
 376 // Return the .TOC. section address to R_PPC64_TOC relocations.
 377 uint64_t RuntimeDyldELF::findPPC64TOC() const {
 378   // The TOC consists of sections .got, .toc, .tocbss, .plt in that
 379   // order. The TOC starts where the first of these sections starts.
 380   SectionList::const_iterator it = Sections.begin();
 381   SectionList::const_iterator ite = Sections.end();
 382   for (; it != ite; ++it) {
 383     if (it->Name == ".got" ||
 384         it->Name == ".toc" ||
 385         it->Name == ".tocbss" ||
 386         it->Name == ".plt")
 387       break;
 388   }
 389   if (it == ite) {
 390     // This may happen for
 391     // * references to TOC base base (sym@toc, .odp relocation) without
 392     // a .toc directive.
 393     // In this case just use the first section (which is usually
 394     // the .odp) since the code won't reference the .toc base
 395     // directly.
 396     it = Sections.begin();
 397   }
 398   assert (it != ite);
 399   // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
 400   // thus permitting a full 64 Kbytes segment.
 401   return it->LoadAddress + 0x8000;
 402 }
 403
 404 // Returns the sections and offset associated with the ODP entry referenced
 405 // by Symbol.
 406 void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj,
 407                                          ObjSectionToIDMap &LocalSections,
 408                                          RelocationValueRef &Rel) {
 409   // Get the ELF symbol value (st_value) to compare with Relocation offset in
 410   // .opd entries
 411
 412   error_code err;
 413   for (section_iterator si = Obj.begin_sections(),
 414      se = Obj.end_sections(); si != se; si.increment(err)) {
 415     StringRef SectionName;
 416     check(si->getName(SectionName));
 417     if (SectionName != ".opd")
 418       continue;
 419
 420     for (relocation_iterator i = si->begin_relocations(),
 421          e = si->end_relocations(); i != e;) {
 422       check(err);
 423
 424       // The R_PPC64_ADDR64 relocation indicates the first field
 425       // of a .opd entry
 426       uint64_t TypeFunc;
 427       check(i->getType(TypeFunc));
 428       if (TypeFunc != ELF::R_PPC64_ADDR64) {
 429         i.increment(err);
 430         continue;
 431       }
 432
 433       SymbolRef TargetSymbol;
 434       uint64_t TargetSymbolOffset;
 435       int64_t TargetAdditionalInfo;
 436       check(i->getSymbol(TargetSymbol));
 437       check(i->getOffset(TargetSymbolOffset));
 438       check(i->getAdditionalInfo(TargetAdditionalInfo));
 439
 440       i = i.increment(err);
 441       if (i == e)
 442         break;
 443       check(err);
 444
 445       // Just check if following relocation is a R_PPC64_TOC
 446       uint64_t TypeTOC;
 447       check(i->getType(TypeTOC));
 448       if (TypeTOC != ELF::R_PPC64_TOC)
 449         continue;
 450
 451       // Finally compares the Symbol value and the target symbol offset
 452       // to check if this .opd entry refers to the symbol the relocation
 453       // points to.
 454       if (Rel.Addend != (intptr_t)TargetSymbolOffset)
 455         continue;
 456
 457       section_iterator tsi(Obj.end_sections());
 458       check(TargetSymbol.getSection(tsi));
 459       Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections);
 460       Rel.Addend = (intptr_t)TargetAdditionalInfo;
 461       return;
 462     }
 463   }
 464   llvm_unreachable("Attempting to get address of ODP entry!");
 465 }
 466
 467 // Relocation masks following the #lo(value), #hi(value), #higher(value),
 468 // and #highest(value) macros defined in section 4.5.1. Relocation Types
 469 // in PPC-elf64abi document.
 470 //
 471 static inline
 472 uint16_t applyPPClo (uint64_t value)
 473 {
 474   return value & 0xffff;
 475 }
 476
 477 static inline
 478 uint16_t applyPPChi (uint64_t value)
 479 {
 480   return (value >> 16) & 0xffff;
 481 }
 482
 483 static inline
 484 uint16_t applyPPChigher (uint64_t value)
 485 {
 486   return (value >> 32) & 0xffff;
 487 }
 488
 489 static inline
 490 uint16_t applyPPChighest (uint64_t value)
 491 {
 492   return (value >> 48) & 0xffff;
 493 }
 494
 495 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
 496                                             uint64_t Offset,
 497                                             uint64_t Value,
 498                                             uint32_t Type,
 499                                             int64_t Addend) {
 500   uint8_t* LocalAddress = Section.Address + Offset;
 501   switch (Type) {
 502   default:
 503     llvm_unreachable("Relocation type not implemented yet!");
 504   break;
 505   case ELF::R_PPC64_ADDR16_LO :
 506     writeInt16BE(LocalAddress, applyPPClo (Value + Addend));
 507     break;
 508   case ELF::R_PPC64_ADDR16_HI :
 509     writeInt16BE(LocalAddress, applyPPChi (Value + Addend));
 510     break;
 511   case ELF::R_PPC64_ADDR16_HIGHER :
 512     writeInt16BE(LocalAddress, applyPPChigher (Value + Addend));
 513     break;
 514   case ELF::R_PPC64_ADDR16_HIGHEST :
 515     writeInt16BE(LocalAddress, applyPPChighest (Value + Addend));
 516     break;
 517   case ELF::R_PPC64_ADDR14 : {
 518     assert(((Value + Addend) & 3) == 0);
 519     // Preserve the AA/LK bits in the branch instruction
 520     uint8_t aalk = *(LocalAddress+3);
 521     writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
 522   } break;
 523   case ELF::R_PPC64_ADDR32 : {
 524     int32_t Result = static_cast<int32_t>(Value + Addend);
 525     if (SignExtend32<32>(Result) != Result)
 526       llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
 527     writeInt32BE(LocalAddress, Result);
 528   } break;
 529   case ELF::R_PPC64_REL24 : {
 530     uint64_t FinalAddress = (Section.LoadAddress + Offset);
 531     int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
 532     if (SignExtend32<24>(delta) != delta)
 533       llvm_unreachable("Relocation R_PPC64_REL24 overflow");
 534     // Generates a 'bl <address>' instruction
 535     writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
 536   } break;
 537   case ELF::R_PPC64_REL32 : {
 538     uint64_t FinalAddress = (Section.LoadAddress + Offset);
 539     int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
 540     if (SignExtend32<32>(delta) != delta)
 541       llvm_unreachable("Relocation R_PPC64_REL32 overflow");
 542     writeInt32BE(LocalAddress, delta);
 543   } break;
 544   case ELF::R_PPC64_ADDR64 :
 545     writeInt64BE(LocalAddress, Value + Addend);
 546     break;
 547   case ELF::R_PPC64_TOC :
 548     writeInt64BE(LocalAddress, findPPC64TOC());
 549     break;
 550   case ELF::R_PPC64_TOC16 : {
 551     uint64_t TOCStart = findPPC64TOC();
 552     Value = applyPPClo((Value + Addend) - TOCStart);
 553     writeInt16BE(LocalAddress, applyPPClo(Value));
 554   } break;
 555   case ELF::R_PPC64_TOC16_DS : {
 556     uint64_t TOCStart = findPPC64TOC();
 557     Value = ((Value + Addend) - TOCStart);
 558     writeInt16BE(LocalAddress, applyPPClo(Value));
 559   } break;
 560   }
 561 }
 562
 563 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
 564                                               uint64_t Offset,
 565                                               uint64_t Value,
 566                                               uint32_t Type,
 567                                               int64_t Addend) {
 568   uint8_t *LocalAddress = Section.Address + Offset;
 569   switch (Type) {
 570   default:
 571     llvm_unreachable("Relocation type not implemented yet!");
 572     break;
 573   case ELF::R_390_PC16DBL:
 574   case ELF::R_390_PLT16DBL: {
 575     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 576     assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
 577     writeInt16BE(LocalAddress, Delta / 2);
 578     break;
 579   }
 580   case ELF::R_390_PC32DBL:
 581   case ELF::R_390_PLT32DBL: {
 582     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 583     assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
 584     writeInt32BE(LocalAddress, Delta / 2);
 585     break;
 586   }
 587   case ELF::R_390_PC32: {
 588     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 589     assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
 590     writeInt32BE(LocalAddress, Delta);
 591     break;
 592   }
 593   case ELF::R_390_64:
 594     writeInt64BE(LocalAddress, Value + Addend);
 595     break;
 596   }
 597 }
 598
 599 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
 600                                        uint64_t Value) {
 601   const SectionEntry &Section = Sections[RE.SectionID];
 602   return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend);
 603 }
 604
 605 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
 606                                        uint64_t Offset,
 607                                        uint64_t Value,
 608                                        uint32_t Type,
 609                                        int64_t Addend) {
 610   switch (Arch) {
 611   case Triple::x86_64:
 612     resolveX86_64Relocation(Section, Offset, Value, Type, Addend);
 613     break;
 614   case Triple::x86:
 615     resolveX86Relocation(Section, Offset,
 616                          (uint32_t)(Value & 0xffffffffL), Type,
 617                          (uint32_t)(Addend & 0xffffffffL));
 618     break;
 619   case Triple::arm:    // Fall through.
 620   case Triple::thumb:
 621     resolveARMRelocation(Section, Offset,
 622                          (uint32_t)(Value & 0xffffffffL), Type,
 623                          (uint32_t)(Addend & 0xffffffffL));
 624     break;
 625   case Triple::mips:    // Fall through.
 626   case Triple::mipsel:
 627     resolveMIPSRelocation(Section, Offset,
 628                           (uint32_t)(Value & 0xffffffffL), Type,
 629                           (uint32_t)(Addend & 0xffffffffL));
 630     break;
 631   case Triple::ppc64:
 632     resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
 633     break;
 634   case Triple::systemz:
 635     resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
 636     break;
 637   default: llvm_unreachable("Unsupported CPU type!");
 638   }
 639 }
 640
 641 void RuntimeDyldELF::processRelocationRef(unsigned SectionID,
 642                                           RelocationRef RelI,
 643                                           ObjectImage &Obj,
 644                                           ObjSectionToIDMap &ObjSectionToID,
 645                                           const SymbolTableMap &Symbols,
 646                                           StubMap &Stubs) {
 647   uint64_t RelType;
 648   Check(RelI.getType(RelType));
 649   int64_t Addend;
 650   Check(RelI.getAdditionalInfo(Addend));
 651   SymbolRef Symbol;
 652   Check(RelI.getSymbol(Symbol));
 653
 654   // Obtain the symbol name which is referenced in the relocation
 655   StringRef TargetName;
 656   Symbol.getName(TargetName);
 657   DEBUG(dbgs() << "\t\tRelType: " << RelType
 658                << " Addend: " << Addend
 659                << " TargetName: " << TargetName
 660                << "\n");
 661   RelocationValueRef Value;
 662   // First search for the symbol in the local symbol table
 663   SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
 664   SymbolRef::Type SymType;
 665   Symbol.getType(SymType);
 666   if (lsi != Symbols.end()) {
 667     Value.SectionID = lsi->second.first;
 668     Value.Addend = lsi->second.second + Addend;
 669   } else {
 670     // Search for the symbol in the global symbol table
 671     SymbolTableMap::const_iterator gsi =
 672         GlobalSymbolTable.find(TargetName.data());
 673     if (gsi != GlobalSymbolTable.end()) {
 674       Value.SectionID = gsi->second.first;
 675       Value.Addend = gsi->second.second + Addend;
 676     } else {
 677       switch (SymType) {
 678         case SymbolRef::ST_Debug: {
 679           // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
 680           // and can be changed by another developers. Maybe best way is add
 681           // a new symbol type ST_Section to SymbolRef and use it.
 682           section_iterator si(Obj.end_sections());
 683           Symbol.getSection(si);
 684           if (si == Obj.end_sections())
 685             llvm_unreachable("Symbol section not found, bad object file format!");
 686           DEBUG(dbgs() << "\t\tThis is section symbol\n");
 687           // Default to 'true' in case isText fails (though it never does).
 688           bool isCode = true;
 689           si->isText(isCode);
 690           Value.SectionID = findOrEmitSection(Obj,
 691                                               (*si),
 692                                               isCode,
 693                                               ObjSectionToID);
 694           Value.Addend = Addend;
 695           break;
 696         }
 697         case SymbolRef::ST_Unknown: {
 698           Value.SymbolName = TargetName.data();
 699           Value.Addend = Addend;
 700           break;
 701         }
 702         default:
 703           llvm_unreachable("Unresolved symbol type!");
 704           break;
 705       }
 706     }
 707   }
 708   uint64_t Offset;
 709   Check(RelI.getOffset(Offset));
 710
 711   DEBUG(dbgs() << "\t\tSectionID: " << SectionID
 712                << " Offset: " << Offset
 713                << "\n");
 714   if (Arch == Triple::arm &&
 715       (RelType == ELF::R_ARM_PC24 ||
 716        RelType == ELF::R_ARM_CALL ||
 717        RelType == ELF::R_ARM_JUMP24)) {
 718     // This is an ARM branch relocation, need to use a stub function.
 719     DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.");
 720     SectionEntry &Section = Sections[SectionID];
 721
 722     // Look for an existing stub.
 723     StubMap::const_iterator i = Stubs.find(Value);
 724     if (i != Stubs.end()) {
 725         resolveRelocation(Section, Offset,
 726                           (uint64_t)Section.Address + i->second, RelType, 0);
 727       DEBUG(dbgs() << " Stub function found\n");
 728     } else {
 729       // Create a new stub function.
 730       DEBUG(dbgs() << " Create a new stub function\n");
 731       Stubs[Value] = Section.StubOffset;
 732       uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 733                                                    Section.StubOffset);
 734       RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
 735                          ELF::R_ARM_ABS32, Value.Addend);
 736       if (Value.SymbolName)
 737         addRelocationForSymbol(RE, Value.SymbolName);
 738       else
 739         addRelocationForSection(RE, Value.SectionID);
 740
 741       resolveRelocation(Section, Offset,
 742                         (uint64_t)Section.Address + Section.StubOffset,
 743                         RelType, 0);
 744       Section.StubOffset += getMaxStubSize();
 745     }
 746   } else if ((Arch == Triple::mipsel || Arch == Triple::mips) &&
 747              RelType == ELF::R_MIPS_26) {
 748     // This is an Mips branch relocation, need to use a stub function.
 749     DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
 750     SectionEntry &Section = Sections[SectionID];
 751     uint8_t *Target = Section.Address + Offset;
 752     uint32_t *TargetAddress = (uint32_t *)Target;
 753
 754     // Extract the addend from the instruction.
 755     uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2;
 756
 757     Value.Addend += Addend;
 758
 759     //  Look up for existing stub.
 760     StubMap::const_iterator i = Stubs.find(Value);
 761     if (i != Stubs.end()) {
 762       resolveRelocation(Section, Offset,
 763                         (uint64_t)Section.Address + i->second, RelType, 0);
 764       DEBUG(dbgs() << " Stub function found\n");
 765     } else {
 766       // Create a new stub function.
 767       DEBUG(dbgs() << " Create a new stub function\n");
 768       Stubs[Value] = Section.StubOffset;
 769       uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 770                                                    Section.StubOffset);
 771
 772       // Creating Hi and Lo relocations for the filled stub instructions.
 773       RelocationEntry REHi(SectionID,
 774                            StubTargetAddr - Section.Address,
 775                            ELF::R_MIPS_HI16, Value.Addend);
 776       RelocationEntry RELo(SectionID,
 777                            StubTargetAddr - Section.Address + 4,
 778                            ELF::R_MIPS_LO16, Value.Addend);
 779
 780       if (Value.SymbolName) {
 781         addRelocationForSymbol(REHi, Value.SymbolName);
 782         addRelocationForSymbol(RELo, Value.SymbolName);
 783       } else {
 784         addRelocationForSection(REHi, Value.SectionID);
 785         addRelocationForSection(RELo, Value.SectionID);
 786       }
 787
 788       resolveRelocation(Section, Offset,
 789                         (uint64_t)Section.Address + Section.StubOffset,
 790                         RelType, 0);
 791       Section.StubOffset += getMaxStubSize();
 792     }
 793   } else if (Arch == Triple::ppc64) {
 794     if (RelType == ELF::R_PPC64_REL24) {
 795       // A PPC branch relocation will need a stub function if the target is
 796       // an external symbol (Symbol::ST_Unknown) or if the target address
 797       // is not within the signed 24-bits branch address.
 798       SectionEntry &Section = Sections[SectionID];
 799       uint8_t *Target = Section.Address + Offset;
 800       bool RangeOverflow = false;
 801       if (SymType != SymbolRef::ST_Unknown) {
 802         // A function call may points to the .opd entry, so the final symbol value
 803         // in calculated based in the relocation values in .opd section.
 804         findOPDEntrySection(Obj, ObjSectionToID, Value);
 805         uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
 806         int32_t delta = static_cast<int32_t>(Target - RelocTarget);
 807         // If it is within 24-bits branch range, just set the branch target
 808         if (SignExtend32<24>(delta) == delta) {
 809           RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
 810           if (Value.SymbolName)
 811             addRelocationForSymbol(RE, Value.SymbolName);
 812           else
 813             addRelocationForSection(RE, Value.SectionID);
 814         } else {
 815           RangeOverflow = true;
 816         }
 817       }
 818       if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) {
 819         // It is an external symbol (SymbolRef::ST_Unknown) or within a range
 820         // larger than 24-bits.
 821         StubMap::const_iterator i = Stubs.find(Value);
 822         if (i != Stubs.end()) {
 823           // Symbol function stub already created, just relocate to it
 824           resolveRelocation(Section, Offset,
 825                             (uint64_t)Section.Address + i->second, RelType, 0);
 826           DEBUG(dbgs() << " Stub function found\n");
 827         } else {
 828           // Create a new stub function.
 829           DEBUG(dbgs() << " Create a new stub function\n");
 830           Stubs[Value] = Section.StubOffset;
 831           uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 832                                                        Section.StubOffset);
 833           RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
 834                              ELF::R_PPC64_ADDR64, Value.Addend);
 835
 836           // Generates the 64-bits address loads as exemplified in section
 837           // 4.5.1 in PPC64 ELF ABI.
 838           RelocationEntry REhst(SectionID,
 839                                 StubTargetAddr - Section.Address + 2,
 840                                 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
 841           RelocationEntry REhr(SectionID,
 842                                StubTargetAddr - Section.Address + 6,
 843                                ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
 844           RelocationEntry REh(SectionID,
 845                               StubTargetAddr - Section.Address + 14,
 846                               ELF::R_PPC64_ADDR16_HI, Value.Addend);
 847           RelocationEntry REl(SectionID,
 848                               StubTargetAddr - Section.Address + 18,
 849                               ELF::R_PPC64_ADDR16_LO, Value.Addend);
 850
 851           if (Value.SymbolName) {
 852             addRelocationForSymbol(REhst, Value.SymbolName);
 853             addRelocationForSymbol(REhr,  Value.SymbolName);
 854             addRelocationForSymbol(REh,   Value.SymbolName);
 855             addRelocationForSymbol(REl,   Value.SymbolName);
 856           } else {
 857             addRelocationForSection(REhst, Value.SectionID);
 858             addRelocationForSection(REhr,  Value.SectionID);
 859             addRelocationForSection(REh,   Value.SectionID);
 860             addRelocationForSection(REl,   Value.SectionID);
 861           }
 862
 863           resolveRelocation(Section, Offset,
 864                             (uint64_t)Section.Address + Section.StubOffset,
 865                             RelType, 0);
 866           if (SymType == SymbolRef::ST_Unknown)
 867             // Restore the TOC for external calls
 868             writeInt32BE(Target+4, 0xE8410028); // ld r2,40(r1)
 869           Section.StubOffset += getMaxStubSize();
 870         }
 871       }
 872     } else {
 873       RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
 874       // Extra check to avoid relocation againt empty symbols (usually
 875       // the R_PPC64_TOC).
 876       if (Value.SymbolName && !TargetName.empty())
 877         addRelocationForSymbol(RE, Value.SymbolName);
 878       else
 879         addRelocationForSection(RE, Value.SectionID);
 880     }
 881   } else if (Arch == Triple::systemz &&
 882              (RelType == ELF::R_390_PLT32DBL ||
 883               RelType == ELF::R_390_GOTENT)) {
 884     // Create function stubs for both PLT and GOT references, regardless of
 885     // whether the GOT reference is to data or code.  The stub contains the
 886     // full address of the symbol, as needed by GOT references, and the
 887     // executable part only adds an overhead of 8 bytes.
 888     //
 889     // We could try to conserve space by allocating the code and data
 890     // parts of the stub separately.  However, as things stand, we allocate
 891     // a stub for every relocation, so using a GOT in JIT code should be
 892     // no less space efficient than using an explicit constant pool.
 893     DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
 894     SectionEntry &Section = Sections[SectionID];
 895
 896     // Look for an existing stub.
 897     StubMap::const_iterator i = Stubs.find(Value);
 898     uintptr_t StubAddress;
 899     if (i != Stubs.end()) {
 900       StubAddress = uintptr_t(Section.Address) + i->second;
 901       DEBUG(dbgs() << " Stub function found\n");
 902     } else {
 903       // Create a new stub function.
 904       DEBUG(dbgs() << " Create a new stub function\n");
 905
 906       uintptr_t BaseAddress = uintptr_t(Section.Address);
 907       uintptr_t StubAlignment = getStubAlignment();
 908       StubAddress = (BaseAddress + Section.StubOffset +
 909                      StubAlignment - 1) & -StubAlignment;
 910       unsigned StubOffset = StubAddress - BaseAddress;
 911
 912       Stubs[Value] = StubOffset;
 913       createStubFunction((uint8_t *)StubAddress);
 914       RelocationEntry RE(SectionID, StubOffset + 8,
 915                          ELF::R_390_64, Value.Addend - Addend);
 916       if (Value.SymbolName)
 917         addRelocationForSymbol(RE, Value.SymbolName);
 918       else
 919         addRelocationForSection(RE, Value.SectionID);
 920       Section.StubOffset = StubOffset + getMaxStubSize();
 921     }
 922
 923     if (RelType == ELF::R_390_GOTENT)
 924       resolveRelocation(Section, Offset, StubAddress + 8,
 925                         ELF::R_390_PC32DBL, Addend);
 926     else
 927       resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
 928   } else {
 929     RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
 930     if (Value.SymbolName)
 931       addRelocationForSymbol(RE, Value.SymbolName);
 932     else
 933       addRelocationForSection(RE, Value.SectionID);
 934   }
 935 }
 936
 937 bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const {
 938   if (Buffer->getBufferSize() < strlen(ELF::ElfMagic))
 939     return false;
 940   return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
 941 }
 942 } // namespace llvm