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::resolveAArch64Relocation(const SectionEntry &Section,
 273                                               uint64_t Offset,
 274                                               uint64_t Value,
 275                                               uint32_t Type,
 276                                               int64_t Addend) {
 277   uint32_t *TargetPtr = reinterpret_cast<uint32_t*>(Section.Address + Offset);
 278   uint64_t FinalAddress = Section.LoadAddress + Offset;
 279
 280   DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
 281                << format("%llx", Section.Address + Offset)
 282                << " FinalAddress: 0x" << format("%llx",FinalAddress)
 283                << " Value: 0x" << format("%llx",Value)
 284                << " Type: 0x" << format("%x",Type)
 285                << " Addend: 0x" << format("%llx",Addend)
 286                << "\n");
 287
 288   switch (Type) {
 289   default:
 290     llvm_unreachable("Relocation type not implemented yet!");
 291     break;
 292   case ELF::R_AARCH64_PREL32: { // test-shift.ll (.eh_frame)
 293     uint64_t Result = Value + Addend - FinalAddress;
 294     assert(static_cast<int64_t>(Result) >= INT32_MIN &&
 295            static_cast<int64_t>(Result) <= UINT32_MAX);
 296     *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU);
 297     break;
 298   }
 299   }
 300 }
 301
 302 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
 303                                           uint64_t Offset,
 304                                           uint32_t Value,
 305                                           uint32_t Type,
 306                                           int32_t Addend) {
 307   // TODO: Add Thumb relocations.
 308   uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
 309   uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
 310   Value += Addend;
 311
 312   DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
 313                << Section.Address + Offset
 314                << " FinalAddress: " << format("%p",FinalAddress)
 315                << " Value: " << format("%x",Value)
 316                << " Type: " << format("%x",Type)
 317                << " Addend: " << format("%x",Addend)
 318                << "\n");
 319
 320   switch(Type) {
 321   default:
 322     llvm_unreachable("Not implemented relocation type!");
 323
 324   // Write a 32bit value to relocation address, taking into account the
 325   // implicit addend encoded in the target.
 326   case ELF::R_ARM_TARGET1 :
 327   case ELF::R_ARM_ABS32 :
 328     *TargetPtr += Value;
 329     break;
 330
 331   // Write first 16 bit of 32 bit value to the mov instruction.
 332   // Last 4 bit should be shifted.
 333   case ELF::R_ARM_MOVW_ABS_NC :
 334     // We are not expecting any other addend in the relocation address.
 335     // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2
 336     // non-contiguous fields.
 337     assert((*TargetPtr & 0x000F0FFF) == 0);
 338     Value = Value & 0xFFFF;
 339     *TargetPtr |= Value & 0xFFF;
 340     *TargetPtr |= ((Value >> 12) & 0xF) << 16;
 341     break;
 342
 343   // Write last 16 bit of 32 bit value to the mov instruction.
 344   // Last 4 bit should be shifted.
 345   case ELF::R_ARM_MOVT_ABS :
 346     // We are not expecting any other addend in the relocation address.
 347     // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC.
 348     assert((*TargetPtr & 0x000F0FFF) == 0);
 349     Value = (Value >> 16) & 0xFFFF;
 350     *TargetPtr |= Value & 0xFFF;
 351     *TargetPtr |= ((Value >> 12) & 0xF) << 16;
 352     break;
 353
 354   // Write 24 bit relative value to the branch instruction.
 355   case ELF::R_ARM_PC24 :    // Fall through.
 356   case ELF::R_ARM_CALL :    // Fall through.
 357   case ELF::R_ARM_JUMP24 :
 358     int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
 359     RelValue = (RelValue & 0x03FFFFFC) >> 2;
 360     *TargetPtr &= 0xFF000000;
 361     *TargetPtr |= RelValue;
 362     break;
 363   }
 364 }
 365
 366 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
 367                                            uint64_t Offset,
 368                                            uint32_t Value,
 369                                            uint32_t Type,
 370                                            int32_t Addend) {
 371   uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
 372   Value += Addend;
 373
 374   DEBUG(dbgs() << "resolveMipselocation, LocalAddress: "
 375                << Section.Address + Offset
 376                << " FinalAddress: "
 377                << format("%p",Section.LoadAddress + Offset)
 378                << " Value: " << format("%x",Value)
 379                << " Type: " << format("%x",Type)
 380                << " Addend: " << format("%x",Addend)
 381                << "\n");
 382
 383   switch(Type) {
 384   default:
 385     llvm_unreachable("Not implemented relocation type!");
 386     break;
 387   case ELF::R_MIPS_32:
 388     *TargetPtr = Value + (*TargetPtr);
 389     break;
 390   case ELF::R_MIPS_26:
 391     *TargetPtr = ((*TargetPtr) & 0xfc000000) | (( Value & 0x0fffffff) >> 2);
 392     break;
 393   case ELF::R_MIPS_HI16:
 394     // Get the higher 16-bits. Also add 1 if bit 15 is 1.
 395     Value += ((*TargetPtr) & 0x0000ffff) << 16;
 396     *TargetPtr = ((*TargetPtr) & 0xffff0000) |
 397                  (((Value + 0x8000) >> 16) & 0xffff);
 398     break;
 399    case ELF::R_MIPS_LO16:
 400     Value += ((*TargetPtr) & 0x0000ffff);
 401     *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
 402     break;
 403    }
 404 }
 405
 406 // Return the .TOC. section address to R_PPC64_TOC relocations.
 407 uint64_t RuntimeDyldELF::findPPC64TOC() const {
 408   // The TOC consists of sections .got, .toc, .tocbss, .plt in that
 409   // order. The TOC starts where the first of these sections starts.
 410   SectionList::const_iterator it = Sections.begin();
 411   SectionList::const_iterator ite = Sections.end();
 412   for (; it != ite; ++it) {
 413     if (it->Name == ".got" ||
 414         it->Name == ".toc" ||
 415         it->Name == ".tocbss" ||
 416         it->Name == ".plt")
 417       break;
 418   }
 419   if (it == ite) {
 420     // This may happen for
 421     // * references to TOC base base (sym@toc, .odp relocation) without
 422     // a .toc directive.
 423     // In this case just use the first section (which is usually
 424     // the .odp) since the code won't reference the .toc base
 425     // directly.
 426     it = Sections.begin();
 427   }
 428   assert (it != ite);
 429   // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
 430   // thus permitting a full 64 Kbytes segment.
 431   return it->LoadAddress + 0x8000;
 432 }
 433
 434 // Returns the sections and offset associated with the ODP entry referenced
 435 // by Symbol.
 436 void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj,
 437                                          ObjSectionToIDMap &LocalSections,
 438                                          RelocationValueRef &Rel) {
 439   // Get the ELF symbol value (st_value) to compare with Relocation offset in
 440   // .opd entries
 441
 442   error_code err;
 443   for (section_iterator si = Obj.begin_sections(),
 444      se = Obj.end_sections(); si != se; si.increment(err)) {
 445     StringRef SectionName;
 446     check(si->getName(SectionName));
 447     if (SectionName != ".opd")
 448       continue;
 449
 450     for (relocation_iterator i = si->begin_relocations(),
 451          e = si->end_relocations(); i != e;) {
 452       check(err);
 453
 454       // The R_PPC64_ADDR64 relocation indicates the first field
 455       // of a .opd entry
 456       uint64_t TypeFunc;
 457       check(i->getType(TypeFunc));
 458       if (TypeFunc != ELF::R_PPC64_ADDR64) {
 459         i.increment(err);
 460         continue;
 461       }
 462
 463       SymbolRef TargetSymbol;
 464       uint64_t TargetSymbolOffset;
 465       int64_t TargetAdditionalInfo;
 466       check(i->getSymbol(TargetSymbol));
 467       check(i->getOffset(TargetSymbolOffset));
 468       check(i->getAdditionalInfo(TargetAdditionalInfo));
 469
 470       i = i.increment(err);
 471       if (i == e)
 472         break;
 473       check(err);
 474
 475       // Just check if following relocation is a R_PPC64_TOC
 476       uint64_t TypeTOC;
 477       check(i->getType(TypeTOC));
 478       if (TypeTOC != ELF::R_PPC64_TOC)
 479         continue;
 480
 481       // Finally compares the Symbol value and the target symbol offset
 482       // to check if this .opd entry refers to the symbol the relocation
 483       // points to.
 484       if (Rel.Addend != (intptr_t)TargetSymbolOffset)
 485         continue;
 486
 487       section_iterator tsi(Obj.end_sections());
 488       check(TargetSymbol.getSection(tsi));
 489       Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections);
 490       Rel.Addend = (intptr_t)TargetAdditionalInfo;
 491       return;
 492     }
 493   }
 494   llvm_unreachable("Attempting to get address of ODP entry!");
 495 }
 496
 497 // Relocation masks following the #lo(value), #hi(value), #higher(value),
 498 // and #highest(value) macros defined in section 4.5.1. Relocation Types
 499 // in PPC-elf64abi document.
 500 //
 501 static inline
 502 uint16_t applyPPClo (uint64_t value)
 503 {
 504   return value & 0xffff;
 505 }
 506
 507 static inline
 508 uint16_t applyPPChi (uint64_t value)
 509 {
 510   return (value >> 16) & 0xffff;
 511 }
 512
 513 static inline
 514 uint16_t applyPPChigher (uint64_t value)
 515 {
 516   return (value >> 32) & 0xffff;
 517 }
 518
 519 static inline
 520 uint16_t applyPPChighest (uint64_t value)
 521 {
 522   return (value >> 48) & 0xffff;
 523 }
 524
 525 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
 526                                             uint64_t Offset,
 527                                             uint64_t Value,
 528                                             uint32_t Type,
 529                                             int64_t Addend) {
 530   uint8_t* LocalAddress = Section.Address + Offset;
 531   switch (Type) {
 532   default:
 533     llvm_unreachable("Relocation type not implemented yet!");
 534   break;
 535   case ELF::R_PPC64_ADDR16_LO :
 536     writeInt16BE(LocalAddress, applyPPClo (Value + Addend));
 537     break;
 538   case ELF::R_PPC64_ADDR16_HI :
 539     writeInt16BE(LocalAddress, applyPPChi (Value + Addend));
 540     break;
 541   case ELF::R_PPC64_ADDR16_HIGHER :
 542     writeInt16BE(LocalAddress, applyPPChigher (Value + Addend));
 543     break;
 544   case ELF::R_PPC64_ADDR16_HIGHEST :
 545     writeInt16BE(LocalAddress, applyPPChighest (Value + Addend));
 546     break;
 547   case ELF::R_PPC64_ADDR14 : {
 548     assert(((Value + Addend) & 3) == 0);
 549     // Preserve the AA/LK bits in the branch instruction
 550     uint8_t aalk = *(LocalAddress+3);
 551     writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
 552   } break;
 553   case ELF::R_PPC64_ADDR32 : {
 554     int32_t Result = static_cast<int32_t>(Value + Addend);
 555     if (SignExtend32<32>(Result) != Result)
 556       llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
 557     writeInt32BE(LocalAddress, Result);
 558   } break;
 559   case ELF::R_PPC64_REL24 : {
 560     uint64_t FinalAddress = (Section.LoadAddress + Offset);
 561     int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
 562     if (SignExtend32<24>(delta) != delta)
 563       llvm_unreachable("Relocation R_PPC64_REL24 overflow");
 564     // Generates a 'bl <address>' instruction
 565     writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
 566   } break;
 567   case ELF::R_PPC64_REL32 : {
 568     uint64_t FinalAddress = (Section.LoadAddress + Offset);
 569     int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
 570     if (SignExtend32<32>(delta) != delta)
 571       llvm_unreachable("Relocation R_PPC64_REL32 overflow");
 572     writeInt32BE(LocalAddress, delta);
 573   } break;
 574   case ELF::R_PPC64_ADDR64 :
 575     writeInt64BE(LocalAddress, Value + Addend);
 576     break;
 577   case ELF::R_PPC64_TOC :
 578     writeInt64BE(LocalAddress, findPPC64TOC());
 579     break;
 580   case ELF::R_PPC64_TOC16 : {
 581     uint64_t TOCStart = findPPC64TOC();
 582     Value = applyPPClo((Value + Addend) - TOCStart);
 583     writeInt16BE(LocalAddress, applyPPClo(Value));
 584   } break;
 585   case ELF::R_PPC64_TOC16_DS : {
 586     uint64_t TOCStart = findPPC64TOC();
 587     Value = ((Value + Addend) - TOCStart);
 588     writeInt16BE(LocalAddress, applyPPClo(Value));
 589   } break;
 590   }
 591 }
 592
 593 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
 594                                               uint64_t Offset,
 595                                               uint64_t Value,
 596                                               uint32_t Type,
 597                                               int64_t Addend) {
 598   uint8_t *LocalAddress = Section.Address + Offset;
 599   switch (Type) {
 600   default:
 601     llvm_unreachable("Relocation type not implemented yet!");
 602     break;
 603   case ELF::R_390_PC16DBL:
 604   case ELF::R_390_PLT16DBL: {
 605     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 606     assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
 607     writeInt16BE(LocalAddress, Delta / 2);
 608     break;
 609   }
 610   case ELF::R_390_PC32DBL:
 611   case ELF::R_390_PLT32DBL: {
 612     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 613     assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
 614     writeInt32BE(LocalAddress, Delta / 2);
 615     break;
 616   }
 617   case ELF::R_390_PC32: {
 618     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 619     assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
 620     writeInt32BE(LocalAddress, Delta);
 621     break;
 622   }
 623   case ELF::R_390_64:
 624     writeInt64BE(LocalAddress, Value + Addend);
 625     break;
 626   }
 627 }
 628
 629 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
 630                                        uint64_t Value) {
 631   const SectionEntry &Section = Sections[RE.SectionID];
 632   return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend);
 633 }
 634
 635 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
 636                                        uint64_t Offset,
 637                                        uint64_t Value,
 638                                        uint32_t Type,
 639                                        int64_t Addend) {
 640   switch (Arch) {
 641   case Triple::x86_64:
 642     resolveX86_64Relocation(Section, Offset, Value, Type, Addend);
 643     break;
 644   case Triple::x86:
 645     resolveX86Relocation(Section, Offset,
 646                          (uint32_t)(Value & 0xffffffffL), Type,
 647                          (uint32_t)(Addend & 0xffffffffL));
 648     break;
 649   case Triple::aarch64:
 650     resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
 651     break;
 652   case Triple::arm:    // Fall through.
 653   case Triple::thumb:
 654     resolveARMRelocation(Section, Offset,
 655                          (uint32_t)(Value & 0xffffffffL), Type,
 656                          (uint32_t)(Addend & 0xffffffffL));
 657     break;
 658   case Triple::mips:    // Fall through.
 659   case Triple::mipsel:
 660     resolveMIPSRelocation(Section, Offset,
 661                           (uint32_t)(Value & 0xffffffffL), Type,
 662                           (uint32_t)(Addend & 0xffffffffL));
 663     break;
 664   case Triple::ppc64:
 665     resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
 666     break;
 667   case Triple::systemz:
 668     resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
 669     break;
 670   default: llvm_unreachable("Unsupported CPU type!");
 671   }
 672 }
 673
 674 void RuntimeDyldELF::processRelocationRef(unsigned SectionID,
 675                                           RelocationRef RelI,
 676                                           ObjectImage &Obj,
 677                                           ObjSectionToIDMap &ObjSectionToID,
 678                                           const SymbolTableMap &Symbols,
 679                                           StubMap &Stubs) {
 680   uint64_t RelType;
 681   Check(RelI.getType(RelType));
 682   int64_t Addend;
 683   Check(RelI.getAdditionalInfo(Addend));
 684   SymbolRef Symbol;
 685   Check(RelI.getSymbol(Symbol));
 686
 687   // Obtain the symbol name which is referenced in the relocation
 688   StringRef TargetName;
 689   Symbol.getName(TargetName);
 690   DEBUG(dbgs() << "\t\tRelType: " << RelType
 691                << " Addend: " << Addend
 692                << " TargetName: " << TargetName
 693                << "\n");
 694   RelocationValueRef Value;
 695   // First search for the symbol in the local symbol table
 696   SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
 697   SymbolRef::Type SymType;
 698   Symbol.getType(SymType);
 699   if (lsi != Symbols.end()) {
 700     Value.SectionID = lsi->second.first;
 701     Value.Addend = lsi->second.second + Addend;
 702   } else {
 703     // Search for the symbol in the global symbol table
 704     SymbolTableMap::const_iterator gsi =
 705         GlobalSymbolTable.find(TargetName.data());
 706     if (gsi != GlobalSymbolTable.end()) {
 707       Value.SectionID = gsi->second.first;
 708       Value.Addend = gsi->second.second + Addend;
 709     } else {
 710       switch (SymType) {
 711         case SymbolRef::ST_Debug: {
 712           // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
 713           // and can be changed by another developers. Maybe best way is add
 714           // a new symbol type ST_Section to SymbolRef and use it.
 715           section_iterator si(Obj.end_sections());
 716           Symbol.getSection(si);
 717           if (si == Obj.end_sections())
 718             llvm_unreachable("Symbol section not found, bad object file format!");
 719           DEBUG(dbgs() << "\t\tThis is section symbol\n");
 720           // Default to 'true' in case isText fails (though it never does).
 721           bool isCode = true;
 722           si->isText(isCode);
 723           Value.SectionID = findOrEmitSection(Obj,
 724                                               (*si),
 725                                               isCode,
 726                                               ObjSectionToID);
 727           Value.Addend = Addend;
 728           break;
 729         }
 730         case SymbolRef::ST_Unknown: {
 731           Value.SymbolName = TargetName.data();
 732           Value.Addend = Addend;
 733           break;
 734         }
 735         default:
 736           llvm_unreachable("Unresolved symbol type!");
 737           break;
 738       }
 739     }
 740   }
 741   uint64_t Offset;
 742   Check(RelI.getOffset(Offset));
 743
 744   DEBUG(dbgs() << "\t\tSectionID: " << SectionID
 745                << " Offset: " << Offset
 746                << "\n");
 747   if (Arch == Triple::arm &&
 748       (RelType == ELF::R_ARM_PC24 ||
 749        RelType == ELF::R_ARM_CALL ||
 750        RelType == ELF::R_ARM_JUMP24)) {
 751     // This is an ARM branch relocation, need to use a stub function.
 752     DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.");
 753     SectionEntry &Section = Sections[SectionID];
 754
 755     // Look for an existing stub.
 756     StubMap::const_iterator i = Stubs.find(Value);
 757     if (i != Stubs.end()) {
 758         resolveRelocation(Section, Offset,
 759                           (uint64_t)Section.Address + i->second, RelType, 0);
 760       DEBUG(dbgs() << " Stub function found\n");
 761     } else {
 762       // Create a new stub function.
 763       DEBUG(dbgs() << " Create a new stub function\n");
 764       Stubs[Value] = Section.StubOffset;
 765       uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 766                                                    Section.StubOffset);
 767       RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
 768                          ELF::R_ARM_ABS32, Value.Addend);
 769       if (Value.SymbolName)
 770         addRelocationForSymbol(RE, Value.SymbolName);
 771       else
 772         addRelocationForSection(RE, Value.SectionID);
 773
 774       resolveRelocation(Section, Offset,
 775                         (uint64_t)Section.Address + Section.StubOffset,
 776                         RelType, 0);
 777       Section.StubOffset += getMaxStubSize();
 778     }
 779   } else if ((Arch == Triple::mipsel || Arch == Triple::mips) &&
 780              RelType == ELF::R_MIPS_26) {
 781     // This is an Mips branch relocation, need to use a stub function.
 782     DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
 783     SectionEntry &Section = Sections[SectionID];
 784     uint8_t *Target = Section.Address + Offset;
 785     uint32_t *TargetAddress = (uint32_t *)Target;
 786
 787     // Extract the addend from the instruction.
 788     uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2;
 789
 790     Value.Addend += Addend;
 791
 792     //  Look up for existing stub.
 793     StubMap::const_iterator i = Stubs.find(Value);
 794     if (i != Stubs.end()) {
 795       resolveRelocation(Section, Offset,
 796                         (uint64_t)Section.Address + i->second, RelType, 0);
 797       DEBUG(dbgs() << " Stub function found\n");
 798     } else {
 799       // Create a new stub function.
 800       DEBUG(dbgs() << " Create a new stub function\n");
 801       Stubs[Value] = Section.StubOffset;
 802       uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 803                                                    Section.StubOffset);
 804
 805       // Creating Hi and Lo relocations for the filled stub instructions.
 806       RelocationEntry REHi(SectionID,
 807                            StubTargetAddr - Section.Address,
 808                            ELF::R_MIPS_HI16, Value.Addend);
 809       RelocationEntry RELo(SectionID,
 810                            StubTargetAddr - Section.Address + 4,
 811                            ELF::R_MIPS_LO16, Value.Addend);
 812
 813       if (Value.SymbolName) {
 814         addRelocationForSymbol(REHi, Value.SymbolName);
 815         addRelocationForSymbol(RELo, Value.SymbolName);
 816       } else {
 817         addRelocationForSection(REHi, Value.SectionID);
 818         addRelocationForSection(RELo, Value.SectionID);
 819       }
 820
 821       resolveRelocation(Section, Offset,
 822                         (uint64_t)Section.Address + Section.StubOffset,
 823                         RelType, 0);
 824       Section.StubOffset += getMaxStubSize();
 825     }
 826   } else if (Arch == Triple::ppc64) {
 827     if (RelType == ELF::R_PPC64_REL24) {
 828       // A PPC branch relocation will need a stub function if the target is
 829       // an external symbol (Symbol::ST_Unknown) or if the target address
 830       // is not within the signed 24-bits branch address.
 831       SectionEntry &Section = Sections[SectionID];
 832       uint8_t *Target = Section.Address + Offset;
 833       bool RangeOverflow = false;
 834       if (SymType != SymbolRef::ST_Unknown) {
 835         // A function call may points to the .opd entry, so the final symbol value
 836         // in calculated based in the relocation values in .opd section.
 837         findOPDEntrySection(Obj, ObjSectionToID, Value);
 838         uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
 839         int32_t delta = static_cast<int32_t>(Target - RelocTarget);
 840         // If it is within 24-bits branch range, just set the branch target
 841         if (SignExtend32<24>(delta) == delta) {
 842           RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
 843           if (Value.SymbolName)
 844             addRelocationForSymbol(RE, Value.SymbolName);
 845           else
 846             addRelocationForSection(RE, Value.SectionID);
 847         } else {
 848           RangeOverflow = true;
 849         }
 850       }
 851       if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) {
 852         // It is an external symbol (SymbolRef::ST_Unknown) or within a range
 853         // larger than 24-bits.
 854         StubMap::const_iterator i = Stubs.find(Value);
 855         if (i != Stubs.end()) {
 856           // Symbol function stub already created, just relocate to it
 857           resolveRelocation(Section, Offset,
 858                             (uint64_t)Section.Address + i->second, RelType, 0);
 859           DEBUG(dbgs() << " Stub function found\n");
 860         } else {
 861           // Create a new stub function.
 862           DEBUG(dbgs() << " Create a new stub function\n");
 863           Stubs[Value] = Section.StubOffset;
 864           uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 865                                                        Section.StubOffset);
 866           RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
 867                              ELF::R_PPC64_ADDR64, Value.Addend);
 868
 869           // Generates the 64-bits address loads as exemplified in section
 870           // 4.5.1 in PPC64 ELF ABI.
 871           RelocationEntry REhst(SectionID,
 872                                 StubTargetAddr - Section.Address + 2,
 873                                 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
 874           RelocationEntry REhr(SectionID,
 875                                StubTargetAddr - Section.Address + 6,
 876                                ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
 877           RelocationEntry REh(SectionID,
 878                               StubTargetAddr - Section.Address + 14,
 879                               ELF::R_PPC64_ADDR16_HI, Value.Addend);
 880           RelocationEntry REl(SectionID,
 881                               StubTargetAddr - Section.Address + 18,
 882                               ELF::R_PPC64_ADDR16_LO, Value.Addend);
 883
 884           if (Value.SymbolName) {
 885             addRelocationForSymbol(REhst, Value.SymbolName);
 886             addRelocationForSymbol(REhr,  Value.SymbolName);
 887             addRelocationForSymbol(REh,   Value.SymbolName);
 888             addRelocationForSymbol(REl,   Value.SymbolName);
 889           } else {
 890             addRelocationForSection(REhst, Value.SectionID);
 891             addRelocationForSection(REhr,  Value.SectionID);
 892             addRelocationForSection(REh,   Value.SectionID);
 893             addRelocationForSection(REl,   Value.SectionID);
 894           }
 895
 896           resolveRelocation(Section, Offset,
 897                             (uint64_t)Section.Address + Section.StubOffset,
 898                             RelType, 0);
 899           if (SymType == SymbolRef::ST_Unknown)
 900             // Restore the TOC for external calls
 901             writeInt32BE(Target+4, 0xE8410028); // ld r2,40(r1)
 902           Section.StubOffset += getMaxStubSize();
 903         }
 904       }
 905     } else {
 906       RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
 907       // Extra check to avoid relocation againt empty symbols (usually
 908       // the R_PPC64_TOC).
 909       if (Value.SymbolName && !TargetName.empty())
 910         addRelocationForSymbol(RE, Value.SymbolName);
 911       else
 912         addRelocationForSection(RE, Value.SectionID);
 913     }
 914   } else if (Arch == Triple::systemz &&
 915              (RelType == ELF::R_390_PLT32DBL ||
 916               RelType == ELF::R_390_GOTENT)) {
 917     // Create function stubs for both PLT and GOT references, regardless of
 918     // whether the GOT reference is to data or code.  The stub contains the
 919     // full address of the symbol, as needed by GOT references, and the
 920     // executable part only adds an overhead of 8 bytes.
 921     //
 922     // We could try to conserve space by allocating the code and data
 923     // parts of the stub separately.  However, as things stand, we allocate
 924     // a stub for every relocation, so using a GOT in JIT code should be
 925     // no less space efficient than using an explicit constant pool.
 926     DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
 927     SectionEntry &Section = Sections[SectionID];
 928
 929     // Look for an existing stub.
 930     StubMap::const_iterator i = Stubs.find(Value);
 931     uintptr_t StubAddress;
 932     if (i != Stubs.end()) {
 933       StubAddress = uintptr_t(Section.Address) + i->second;
 934       DEBUG(dbgs() << " Stub function found\n");
 935     } else {
 936       // Create a new stub function.
 937       DEBUG(dbgs() << " Create a new stub function\n");
 938
 939       uintptr_t BaseAddress = uintptr_t(Section.Address);
 940       uintptr_t StubAlignment = getStubAlignment();
 941       StubAddress = (BaseAddress + Section.StubOffset +
 942                      StubAlignment - 1) & -StubAlignment;
 943       unsigned StubOffset = StubAddress - BaseAddress;
 944
 945       Stubs[Value] = StubOffset;
 946       createStubFunction((uint8_t *)StubAddress);
 947       RelocationEntry RE(SectionID, StubOffset + 8,
 948                          ELF::R_390_64, Value.Addend - Addend);
 949       if (Value.SymbolName)
 950         addRelocationForSymbol(RE, Value.SymbolName);
 951       else
 952         addRelocationForSection(RE, Value.SectionID);
 953       Section.StubOffset = StubOffset + getMaxStubSize();
 954     }
 955
 956     if (RelType == ELF::R_390_GOTENT)
 957       resolveRelocation(Section, Offset, StubAddress + 8,
 958                         ELF::R_390_PC32DBL, Addend);
 959     else
 960       resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
 961   } else {
 962     RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
 963     if (Value.SymbolName)
 964       addRelocationForSymbol(RE, Value.SymbolName);
 965     else
 966       addRelocationForSection(RE, Value.SectionID);
 967   }
 968 }
 969
 970 bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const {
 971   if (Buffer->getBufferSize() < strlen(ELF::ElfMagic))
 972     return false;
 973   return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
 974 }
 975 } // namespace llvm