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   case ELF::R_AARCH64_CALL26: // fallthrough
 300   case ELF::R_AARCH64_JUMP26: {
 301     // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
 302     // calculation.
 303     uint64_t BranchImm = Value + Addend - FinalAddress;
 304
 305     // "Check that -2^27 <= result < 2^27".
 306     assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) &&
 307            static_cast<int64_t>(BranchImm) < (1LL << 27));
 308     // Immediate goes in bits 25:0 of B and BL.
 309     *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
 310     break;
 311   }
 312   case ELF::R_AARCH64_MOVW_UABS_G3: {
 313     uint64_t Result = Value + Addend;
 314     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
 315     *TargetPtr |= Result >> (48 - 5);
 316     // Shift is "lsl #48", in bits 22:21
 317     *TargetPtr |= 3 << 21;
 318     break;
 319   }
 320   case ELF::R_AARCH64_MOVW_UABS_G2_NC: {
 321     uint64_t Result = Value + Addend;
 322     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
 323     *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5));
 324     // Shift is "lsl #32", in bits 22:21
 325     *TargetPtr |= 2 << 21;
 326     break;
 327   }
 328   case ELF::R_AARCH64_MOVW_UABS_G1_NC: {
 329     uint64_t Result = Value + Addend;
 330     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
 331     *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5));
 332     // Shift is "lsl #16", in bits 22:21
 333     *TargetPtr |= 1 << 21;
 334     break;
 335   }
 336   case ELF::R_AARCH64_MOVW_UABS_G0_NC: {
 337     uint64_t Result = Value + Addend;
 338     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
 339     *TargetPtr |= ((Result & 0xffffU) << 5);
 340     // Shift is "lsl #0", in bits 22:21. No action needed.
 341     break;
 342   }
 343   }
 344 }
 345
 346 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
 347                                           uint64_t Offset,
 348                                           uint32_t Value,
 349                                           uint32_t Type,
 350                                           int32_t Addend) {
 351   // TODO: Add Thumb relocations.
 352   uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
 353   uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
 354   Value += Addend;
 355
 356   DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
 357                << Section.Address + Offset
 358                << " FinalAddress: " << format("%p",FinalAddress)
 359                << " Value: " << format("%x",Value)
 360                << " Type: " << format("%x",Type)
 361                << " Addend: " << format("%x",Addend)
 362                << "\n");
 363
 364   switch(Type) {
 365   default:
 366     llvm_unreachable("Not implemented relocation type!");
 367
 368   // Write a 32bit value to relocation address, taking into account the
 369   // implicit addend encoded in the target.
 370   case ELF::R_ARM_TARGET1 :
 371   case ELF::R_ARM_ABS32 :
 372     *TargetPtr += Value;
 373     break;
 374
 375   // Write first 16 bit of 32 bit value to the mov instruction.
 376   // Last 4 bit should be shifted.
 377   case ELF::R_ARM_MOVW_ABS_NC :
 378     // We are not expecting any other addend in the relocation address.
 379     // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2
 380     // non-contiguous fields.
 381     assert((*TargetPtr & 0x000F0FFF) == 0);
 382     Value = Value & 0xFFFF;
 383     *TargetPtr |= Value & 0xFFF;
 384     *TargetPtr |= ((Value >> 12) & 0xF) << 16;
 385     break;
 386
 387   // Write last 16 bit of 32 bit value to the mov instruction.
 388   // Last 4 bit should be shifted.
 389   case ELF::R_ARM_MOVT_ABS :
 390     // We are not expecting any other addend in the relocation address.
 391     // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC.
 392     assert((*TargetPtr & 0x000F0FFF) == 0);
 393     Value = (Value >> 16) & 0xFFFF;
 394     *TargetPtr |= Value & 0xFFF;
 395     *TargetPtr |= ((Value >> 12) & 0xF) << 16;
 396     break;
 397
 398   // Write 24 bit relative value to the branch instruction.
 399   case ELF::R_ARM_PC24 :    // Fall through.
 400   case ELF::R_ARM_CALL :    // Fall through.
 401   case ELF::R_ARM_JUMP24 :
 402     int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
 403     RelValue = (RelValue & 0x03FFFFFC) >> 2;
 404     *TargetPtr &= 0xFF000000;
 405     *TargetPtr |= RelValue;
 406     break;
 407   }
 408 }
 409
 410 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
 411                                            uint64_t Offset,
 412                                            uint32_t Value,
 413                                            uint32_t Type,
 414                                            int32_t Addend) {
 415   uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
 416   Value += Addend;
 417
 418   DEBUG(dbgs() << "resolveMipselocation, LocalAddress: "
 419                << Section.Address + Offset
 420                << " FinalAddress: "
 421                << format("%p",Section.LoadAddress + Offset)
 422                << " Value: " << format("%x",Value)
 423                << " Type: " << format("%x",Type)
 424                << " Addend: " << format("%x",Addend)
 425                << "\n");
 426
 427   switch(Type) {
 428   default:
 429     llvm_unreachable("Not implemented relocation type!");
 430     break;
 431   case ELF::R_MIPS_32:
 432     *TargetPtr = Value + (*TargetPtr);
 433     break;
 434   case ELF::R_MIPS_26:
 435     *TargetPtr = ((*TargetPtr) & 0xfc000000) | (( Value & 0x0fffffff) >> 2);
 436     break;
 437   case ELF::R_MIPS_HI16:
 438     // Get the higher 16-bits. Also add 1 if bit 15 is 1.
 439     Value += ((*TargetPtr) & 0x0000ffff) << 16;
 440     *TargetPtr = ((*TargetPtr) & 0xffff0000) |
 441                  (((Value + 0x8000) >> 16) & 0xffff);
 442     break;
 443    case ELF::R_MIPS_LO16:
 444     Value += ((*TargetPtr) & 0x0000ffff);
 445     *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
 446     break;
 447    }
 448 }
 449
 450 // Return the .TOC. section address to R_PPC64_TOC relocations.
 451 uint64_t RuntimeDyldELF::findPPC64TOC() const {
 452   // The TOC consists of sections .got, .toc, .tocbss, .plt in that
 453   // order. The TOC starts where the first of these sections starts.
 454   SectionList::const_iterator it = Sections.begin();
 455   SectionList::const_iterator ite = Sections.end();
 456   for (; it != ite; ++it) {
 457     if (it->Name == ".got" ||
 458         it->Name == ".toc" ||
 459         it->Name == ".tocbss" ||
 460         it->Name == ".plt")
 461       break;
 462   }
 463   if (it == ite) {
 464     // This may happen for
 465     // * references to TOC base base (sym@toc, .odp relocation) without
 466     // a .toc directive.
 467     // In this case just use the first section (which is usually
 468     // the .odp) since the code won't reference the .toc base
 469     // directly.
 470     it = Sections.begin();
 471   }
 472   assert (it != ite);
 473   // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
 474   // thus permitting a full 64 Kbytes segment.
 475   return it->LoadAddress + 0x8000;
 476 }
 477
 478 // Returns the sections and offset associated with the ODP entry referenced
 479 // by Symbol.
 480 void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj,
 481                                          ObjSectionToIDMap &LocalSections,
 482                                          RelocationValueRef &Rel) {
 483   // Get the ELF symbol value (st_value) to compare with Relocation offset in
 484   // .opd entries
 485
 486   error_code err;
 487   for (section_iterator si = Obj.begin_sections(),
 488      se = Obj.end_sections(); si != se; si.increment(err)) {
 489     StringRef SectionName;
 490     check(si->getName(SectionName));
 491     if (SectionName != ".opd")
 492       continue;
 493
 494     for (relocation_iterator i = si->begin_relocations(),
 495          e = si->end_relocations(); i != e;) {
 496       check(err);
 497
 498       // The R_PPC64_ADDR64 relocation indicates the first field
 499       // of a .opd entry
 500       uint64_t TypeFunc;
 501       check(i->getType(TypeFunc));
 502       if (TypeFunc != ELF::R_PPC64_ADDR64) {
 503         i.increment(err);
 504         continue;
 505       }
 506
 507       SymbolRef TargetSymbol;
 508       uint64_t TargetSymbolOffset;
 509       int64_t TargetAdditionalInfo;
 510       check(i->getSymbol(TargetSymbol));
 511       check(i->getOffset(TargetSymbolOffset));
 512       check(i->getAdditionalInfo(TargetAdditionalInfo));
 513
 514       i = i.increment(err);
 515       if (i == e)
 516         break;
 517       check(err);
 518
 519       // Just check if following relocation is a R_PPC64_TOC
 520       uint64_t TypeTOC;
 521       check(i->getType(TypeTOC));
 522       if (TypeTOC != ELF::R_PPC64_TOC)
 523         continue;
 524
 525       // Finally compares the Symbol value and the target symbol offset
 526       // to check if this .opd entry refers to the symbol the relocation
 527       // points to.
 528       if (Rel.Addend != (intptr_t)TargetSymbolOffset)
 529         continue;
 530
 531       section_iterator tsi(Obj.end_sections());
 532       check(TargetSymbol.getSection(tsi));
 533       Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections);
 534       Rel.Addend = (intptr_t)TargetAdditionalInfo;
 535       return;
 536     }
 537   }
 538   llvm_unreachable("Attempting to get address of ODP entry!");
 539 }
 540
 541 // Relocation masks following the #lo(value), #hi(value), #higher(value),
 542 // and #highest(value) macros defined in section 4.5.1. Relocation Types
 543 // in PPC-elf64abi document.
 544 //
 545 static inline
 546 uint16_t applyPPClo (uint64_t value)
 547 {
 548   return value & 0xffff;
 549 }
 550
 551 static inline
 552 uint16_t applyPPChi (uint64_t value)
 553 {
 554   return (value >> 16) & 0xffff;
 555 }
 556
 557 static inline
 558 uint16_t applyPPChigher (uint64_t value)
 559 {
 560   return (value >> 32) & 0xffff;
 561 }
 562
 563 static inline
 564 uint16_t applyPPChighest (uint64_t value)
 565 {
 566   return (value >> 48) & 0xffff;
 567 }
 568
 569 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
 570                                             uint64_t Offset,
 571                                             uint64_t Value,
 572                                             uint32_t Type,
 573                                             int64_t Addend) {
 574   uint8_t* LocalAddress = Section.Address + Offset;
 575   switch (Type) {
 576   default:
 577     llvm_unreachable("Relocation type not implemented yet!");
 578   break;
 579   case ELF::R_PPC64_ADDR16_LO :
 580     writeInt16BE(LocalAddress, applyPPClo (Value + Addend));
 581     break;
 582   case ELF::R_PPC64_ADDR16_HI :
 583     writeInt16BE(LocalAddress, applyPPChi (Value + Addend));
 584     break;
 585   case ELF::R_PPC64_ADDR16_HIGHER :
 586     writeInt16BE(LocalAddress, applyPPChigher (Value + Addend));
 587     break;
 588   case ELF::R_PPC64_ADDR16_HIGHEST :
 589     writeInt16BE(LocalAddress, applyPPChighest (Value + Addend));
 590     break;
 591   case ELF::R_PPC64_ADDR14 : {
 592     assert(((Value + Addend) & 3) == 0);
 593     // Preserve the AA/LK bits in the branch instruction
 594     uint8_t aalk = *(LocalAddress+3);
 595     writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
 596   } break;
 597   case ELF::R_PPC64_ADDR32 : {
 598     int32_t Result = static_cast<int32_t>(Value + Addend);
 599     if (SignExtend32<32>(Result) != Result)
 600       llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
 601     writeInt32BE(LocalAddress, Result);
 602   } break;
 603   case ELF::R_PPC64_REL24 : {
 604     uint64_t FinalAddress = (Section.LoadAddress + Offset);
 605     int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
 606     if (SignExtend32<24>(delta) != delta)
 607       llvm_unreachable("Relocation R_PPC64_REL24 overflow");
 608     // Generates a 'bl <address>' instruction
 609     writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
 610   } break;
 611   case ELF::R_PPC64_REL32 : {
 612     uint64_t FinalAddress = (Section.LoadAddress + Offset);
 613     int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
 614     if (SignExtend32<32>(delta) != delta)
 615       llvm_unreachable("Relocation R_PPC64_REL32 overflow");
 616     writeInt32BE(LocalAddress, delta);
 617   } break;
 618   case ELF::R_PPC64_ADDR64 :
 619     writeInt64BE(LocalAddress, Value + Addend);
 620     break;
 621   case ELF::R_PPC64_TOC :
 622     writeInt64BE(LocalAddress, findPPC64TOC());
 623     break;
 624   case ELF::R_PPC64_TOC16 : {
 625     uint64_t TOCStart = findPPC64TOC();
 626     Value = applyPPClo((Value + Addend) - TOCStart);
 627     writeInt16BE(LocalAddress, applyPPClo(Value));
 628   } break;
 629   case ELF::R_PPC64_TOC16_DS : {
 630     uint64_t TOCStart = findPPC64TOC();
 631     Value = ((Value + Addend) - TOCStart);
 632     writeInt16BE(LocalAddress, applyPPClo(Value));
 633   } break;
 634   }
 635 }
 636
 637 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
 638                                               uint64_t Offset,
 639                                               uint64_t Value,
 640                                               uint32_t Type,
 641                                               int64_t Addend) {
 642   uint8_t *LocalAddress = Section.Address + Offset;
 643   switch (Type) {
 644   default:
 645     llvm_unreachable("Relocation type not implemented yet!");
 646     break;
 647   case ELF::R_390_PC16DBL:
 648   case ELF::R_390_PLT16DBL: {
 649     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 650     assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
 651     writeInt16BE(LocalAddress, Delta / 2);
 652     break;
 653   }
 654   case ELF::R_390_PC32DBL:
 655   case ELF::R_390_PLT32DBL: {
 656     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 657     assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
 658     writeInt32BE(LocalAddress, Delta / 2);
 659     break;
 660   }
 661   case ELF::R_390_PC32: {
 662     int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
 663     assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
 664     writeInt32BE(LocalAddress, Delta);
 665     break;
 666   }
 667   case ELF::R_390_64:
 668     writeInt64BE(LocalAddress, Value + Addend);
 669     break;
 670   }
 671 }
 672
 673 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
 674                                        uint64_t Value) {
 675   const SectionEntry &Section = Sections[RE.SectionID];
 676   return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend);
 677 }
 678
 679 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
 680                                        uint64_t Offset,
 681                                        uint64_t Value,
 682                                        uint32_t Type,
 683                                        int64_t Addend) {
 684   switch (Arch) {
 685   case Triple::x86_64:
 686     resolveX86_64Relocation(Section, Offset, Value, Type, Addend);
 687     break;
 688   case Triple::x86:
 689     resolveX86Relocation(Section, Offset,
 690                          (uint32_t)(Value & 0xffffffffL), Type,
 691                          (uint32_t)(Addend & 0xffffffffL));
 692     break;
 693   case Triple::aarch64:
 694     resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
 695     break;
 696   case Triple::arm:    // Fall through.
 697   case Triple::thumb:
 698     resolveARMRelocation(Section, Offset,
 699                          (uint32_t)(Value & 0xffffffffL), Type,
 700                          (uint32_t)(Addend & 0xffffffffL));
 701     break;
 702   case Triple::mips:    // Fall through.
 703   case Triple::mipsel:
 704     resolveMIPSRelocation(Section, Offset,
 705                           (uint32_t)(Value & 0xffffffffL), Type,
 706                           (uint32_t)(Addend & 0xffffffffL));
 707     break;
 708   case Triple::ppc64:
 709     resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
 710     break;
 711   case Triple::systemz:
 712     resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
 713     break;
 714   default: llvm_unreachable("Unsupported CPU type!");
 715   }
 716 }
 717
 718 void RuntimeDyldELF::processRelocationRef(unsigned SectionID,
 719                                           RelocationRef RelI,
 720                                           ObjectImage &Obj,
 721                                           ObjSectionToIDMap &ObjSectionToID,
 722                                           const SymbolTableMap &Symbols,
 723                                           StubMap &Stubs) {
 724   uint64_t RelType;
 725   Check(RelI.getType(RelType));
 726   int64_t Addend;
 727   Check(RelI.getAdditionalInfo(Addend));
 728   SymbolRef Symbol;
 729   Check(RelI.getSymbol(Symbol));
 730
 731   // Obtain the symbol name which is referenced in the relocation
 732   StringRef TargetName;
 733   Symbol.getName(TargetName);
 734   DEBUG(dbgs() << "\t\tRelType: " << RelType
 735                << " Addend: " << Addend
 736                << " TargetName: " << TargetName
 737                << "\n");
 738   RelocationValueRef Value;
 739   // First search for the symbol in the local symbol table
 740   SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
 741   SymbolRef::Type SymType;
 742   Symbol.getType(SymType);
 743   if (lsi != Symbols.end()) {
 744     Value.SectionID = lsi->second.first;
 745     Value.Addend = lsi->second.second + Addend;
 746   } else {
 747     // Search for the symbol in the global symbol table
 748     SymbolTableMap::const_iterator gsi =
 749         GlobalSymbolTable.find(TargetName.data());
 750     if (gsi != GlobalSymbolTable.end()) {
 751       Value.SectionID = gsi->second.first;
 752       Value.Addend = gsi->second.second + Addend;
 753     } else {
 754       switch (SymType) {
 755         case SymbolRef::ST_Debug: {
 756           // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
 757           // and can be changed by another developers. Maybe best way is add
 758           // a new symbol type ST_Section to SymbolRef and use it.
 759           section_iterator si(Obj.end_sections());
 760           Symbol.getSection(si);
 761           if (si == Obj.end_sections())
 762             llvm_unreachable("Symbol section not found, bad object file format!");
 763           DEBUG(dbgs() << "\t\tThis is section symbol\n");
 764           // Default to 'true' in case isText fails (though it never does).
 765           bool isCode = true;
 766           si->isText(isCode);
 767           Value.SectionID = findOrEmitSection(Obj,
 768                                               (*si),
 769                                               isCode,
 770                                               ObjSectionToID);
 771           Value.Addend = Addend;
 772           break;
 773         }
 774         case SymbolRef::ST_Unknown: {
 775           Value.SymbolName = TargetName.data();
 776           Value.Addend = Addend;
 777           break;
 778         }
 779         default:
 780           llvm_unreachable("Unresolved symbol type!");
 781           break;
 782       }
 783     }
 784   }
 785   uint64_t Offset;
 786   Check(RelI.getOffset(Offset));
 787
 788   DEBUG(dbgs() << "\t\tSectionID: " << SectionID
 789                << " Offset: " << Offset
 790                << "\n");
 791   if (Arch == Triple::aarch64 &&
 792       (RelType == ELF::R_AARCH64_CALL26 ||
 793        RelType == ELF::R_AARCH64_JUMP26)) {
 794     // This is an AArch64 branch relocation, need to use a stub function.
 795     DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
 796     SectionEntry &Section = Sections[SectionID];
 797
 798     // Look for an existing stub.
 799     StubMap::const_iterator i = Stubs.find(Value);
 800     if (i != Stubs.end()) {
 801         resolveRelocation(Section, Offset,
 802                           (uint64_t)Section.Address + i->second, RelType, 0);
 803       DEBUG(dbgs() << " Stub function found\n");
 804     } else {
 805       // Create a new stub function.
 806       DEBUG(dbgs() << " Create a new stub function\n");
 807       Stubs[Value] = Section.StubOffset;
 808       uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 809                                                    Section.StubOffset);
 810
 811       RelocationEntry REmovz_g3(SectionID,
 812                                 StubTargetAddr - Section.Address,
 813                                 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
 814       RelocationEntry REmovk_g2(SectionID,
 815                                 StubTargetAddr - Section.Address + 4,
 816                                 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
 817       RelocationEntry REmovk_g1(SectionID,
 818                                 StubTargetAddr - Section.Address + 8,
 819                                 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
 820       RelocationEntry REmovk_g0(SectionID,
 821                                 StubTargetAddr - Section.Address + 12,
 822                                 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
 823
 824       if (Value.SymbolName) {
 825         addRelocationForSymbol(REmovz_g3, Value.SymbolName);
 826         addRelocationForSymbol(REmovk_g2, Value.SymbolName);
 827         addRelocationForSymbol(REmovk_g1, Value.SymbolName);
 828         addRelocationForSymbol(REmovk_g0, Value.SymbolName);
 829       } else {
 830         addRelocationForSection(REmovz_g3, Value.SectionID);
 831         addRelocationForSection(REmovk_g2, Value.SectionID);
 832         addRelocationForSection(REmovk_g1, Value.SectionID);
 833         addRelocationForSection(REmovk_g0, Value.SectionID);
 834       }
 835       resolveRelocation(Section, Offset,
 836                         (uint64_t)Section.Address + Section.StubOffset,
 837                         RelType, 0);
 838       Section.StubOffset += getMaxStubSize();
 839     }
 840   } else if (Arch == Triple::arm &&
 841       (RelType == ELF::R_ARM_PC24 ||
 842        RelType == ELF::R_ARM_CALL ||
 843        RelType == ELF::R_ARM_JUMP24)) {
 844     // This is an ARM branch relocation, need to use a stub function.
 845     DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.");
 846     SectionEntry &Section = Sections[SectionID];
 847
 848     // Look for an existing stub.
 849     StubMap::const_iterator i = Stubs.find(Value);
 850     if (i != Stubs.end()) {
 851         resolveRelocation(Section, Offset,
 852                           (uint64_t)Section.Address + i->second, RelType, 0);
 853       DEBUG(dbgs() << " Stub function found\n");
 854     } else {
 855       // Create a new stub function.
 856       DEBUG(dbgs() << " Create a new stub function\n");
 857       Stubs[Value] = Section.StubOffset;
 858       uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 859                                                    Section.StubOffset);
 860       RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
 861                          ELF::R_ARM_ABS32, Value.Addend);
 862       if (Value.SymbolName)
 863         addRelocationForSymbol(RE, Value.SymbolName);
 864       else
 865         addRelocationForSection(RE, Value.SectionID);
 866
 867       resolveRelocation(Section, Offset,
 868                         (uint64_t)Section.Address + Section.StubOffset,
 869                         RelType, 0);
 870       Section.StubOffset += getMaxStubSize();
 871     }
 872   } else if ((Arch == Triple::mipsel || Arch == Triple::mips) &&
 873              RelType == ELF::R_MIPS_26) {
 874     // This is an Mips branch relocation, need to use a stub function.
 875     DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
 876     SectionEntry &Section = Sections[SectionID];
 877     uint8_t *Target = Section.Address + Offset;
 878     uint32_t *TargetAddress = (uint32_t *)Target;
 879
 880     // Extract the addend from the instruction.
 881     uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2;
 882
 883     Value.Addend += Addend;
 884
 885     //  Look up for existing stub.
 886     StubMap::const_iterator i = Stubs.find(Value);
 887     if (i != Stubs.end()) {
 888       resolveRelocation(Section, Offset,
 889                         (uint64_t)Section.Address + i->second, RelType, 0);
 890       DEBUG(dbgs() << " Stub function found\n");
 891     } else {
 892       // Create a new stub function.
 893       DEBUG(dbgs() << " Create a new stub function\n");
 894       Stubs[Value] = Section.StubOffset;
 895       uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 896                                                    Section.StubOffset);
 897
 898       // Creating Hi and Lo relocations for the filled stub instructions.
 899       RelocationEntry REHi(SectionID,
 900                            StubTargetAddr - Section.Address,
 901                            ELF::R_MIPS_HI16, Value.Addend);
 902       RelocationEntry RELo(SectionID,
 903                            StubTargetAddr - Section.Address + 4,
 904                            ELF::R_MIPS_LO16, Value.Addend);
 905
 906       if (Value.SymbolName) {
 907         addRelocationForSymbol(REHi, Value.SymbolName);
 908         addRelocationForSymbol(RELo, Value.SymbolName);
 909       } else {
 910         addRelocationForSection(REHi, Value.SectionID);
 911         addRelocationForSection(RELo, Value.SectionID);
 912       }
 913
 914       resolveRelocation(Section, Offset,
 915                         (uint64_t)Section.Address + Section.StubOffset,
 916                         RelType, 0);
 917       Section.StubOffset += getMaxStubSize();
 918     }
 919   } else if (Arch == Triple::ppc64) {
 920     if (RelType == ELF::R_PPC64_REL24) {
 921       // A PPC branch relocation will need a stub function if the target is
 922       // an external symbol (Symbol::ST_Unknown) or if the target address
 923       // is not within the signed 24-bits branch address.
 924       SectionEntry &Section = Sections[SectionID];
 925       uint8_t *Target = Section.Address + Offset;
 926       bool RangeOverflow = false;
 927       if (SymType != SymbolRef::ST_Unknown) {
 928         // A function call may points to the .opd entry, so the final symbol value
 929         // in calculated based in the relocation values in .opd section.
 930         findOPDEntrySection(Obj, ObjSectionToID, Value);
 931         uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
 932         int32_t delta = static_cast<int32_t>(Target - RelocTarget);
 933         // If it is within 24-bits branch range, just set the branch target
 934         if (SignExtend32<24>(delta) == delta) {
 935           RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
 936           if (Value.SymbolName)
 937             addRelocationForSymbol(RE, Value.SymbolName);
 938           else
 939             addRelocationForSection(RE, Value.SectionID);
 940         } else {
 941           RangeOverflow = true;
 942         }
 943       }
 944       if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) {
 945         // It is an external symbol (SymbolRef::ST_Unknown) or within a range
 946         // larger than 24-bits.
 947         StubMap::const_iterator i = Stubs.find(Value);
 948         if (i != Stubs.end()) {
 949           // Symbol function stub already created, just relocate to it
 950           resolveRelocation(Section, Offset,
 951                             (uint64_t)Section.Address + i->second, RelType, 0);
 952           DEBUG(dbgs() << " Stub function found\n");
 953         } else {
 954           // Create a new stub function.
 955           DEBUG(dbgs() << " Create a new stub function\n");
 956           Stubs[Value] = Section.StubOffset;
 957           uint8_t *StubTargetAddr = createStubFunction(Section.Address +
 958                                                        Section.StubOffset);
 959           RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
 960                              ELF::R_PPC64_ADDR64, Value.Addend);
 961
 962           // Generates the 64-bits address loads as exemplified in section
 963           // 4.5.1 in PPC64 ELF ABI.
 964           RelocationEntry REhst(SectionID,
 965                                 StubTargetAddr - Section.Address + 2,
 966                                 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
 967           RelocationEntry REhr(SectionID,
 968                                StubTargetAddr - Section.Address + 6,
 969                                ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
 970           RelocationEntry REh(SectionID,
 971                               StubTargetAddr - Section.Address + 14,
 972                               ELF::R_PPC64_ADDR16_HI, Value.Addend);
 973           RelocationEntry REl(SectionID,
 974                               StubTargetAddr - Section.Address + 18,
 975                               ELF::R_PPC64_ADDR16_LO, Value.Addend);
 976
 977           if (Value.SymbolName) {
 978             addRelocationForSymbol(REhst, Value.SymbolName);
 979             addRelocationForSymbol(REhr,  Value.SymbolName);
 980             addRelocationForSymbol(REh,   Value.SymbolName);
 981             addRelocationForSymbol(REl,   Value.SymbolName);
 982           } else {
 983             addRelocationForSection(REhst, Value.SectionID);
 984             addRelocationForSection(REhr,  Value.SectionID);
 985             addRelocationForSection(REh,   Value.SectionID);
 986             addRelocationForSection(REl,   Value.SectionID);
 987           }
 988
 989           resolveRelocation(Section, Offset,
 990                             (uint64_t)Section.Address + Section.StubOffset,
 991                             RelType, 0);
 992           if (SymType == SymbolRef::ST_Unknown)
 993             // Restore the TOC for external calls
 994             writeInt32BE(Target+4, 0xE8410028); // ld r2,40(r1)
 995           Section.StubOffset += getMaxStubSize();
 996         }
 997       }
 998     } else {
 999       RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1000       // Extra check to avoid relocation againt empty symbols (usually
1001       // the R_PPC64_TOC).
1002       if (Value.SymbolName && !TargetName.empty())
1003         addRelocationForSymbol(RE, Value.SymbolName);
1004       else
1005         addRelocationForSection(RE, Value.SectionID);
1006     }
1007   } else if (Arch == Triple::systemz &&
1008              (RelType == ELF::R_390_PLT32DBL ||
1009               RelType == ELF::R_390_GOTENT)) {
1010     // Create function stubs for both PLT and GOT references, regardless of
1011     // whether the GOT reference is to data or code.  The stub contains the
1012     // full address of the symbol, as needed by GOT references, and the
1013     // executable part only adds an overhead of 8 bytes.
1014     //
1015     // We could try to conserve space by allocating the code and data
1016     // parts of the stub separately.  However, as things stand, we allocate
1017     // a stub for every relocation, so using a GOT in JIT code should be
1018     // no less space efficient than using an explicit constant pool.
1019     DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1020     SectionEntry &Section = Sections[SectionID];
1021
1022     // Look for an existing stub.
1023     StubMap::const_iterator i = Stubs.find(Value);
1024     uintptr_t StubAddress;
1025     if (i != Stubs.end()) {
1026       StubAddress = uintptr_t(Section.Address) + i->second;
1027       DEBUG(dbgs() << " Stub function found\n");
1028     } else {
1029       // Create a new stub function.
1030       DEBUG(dbgs() << " Create a new stub function\n");
1031
1032       uintptr_t BaseAddress = uintptr_t(Section.Address);
1033       uintptr_t StubAlignment = getStubAlignment();
1034       StubAddress = (BaseAddress + Section.StubOffset +
1035                      StubAlignment - 1) & -StubAlignment;
1036       unsigned StubOffset = StubAddress - BaseAddress;
1037
1038       Stubs[Value] = StubOffset;
1039       createStubFunction((uint8_t *)StubAddress);
1040       RelocationEntry RE(SectionID, StubOffset + 8,
1041                          ELF::R_390_64, Value.Addend - Addend);
1042       if (Value.SymbolName)
1043         addRelocationForSymbol(RE, Value.SymbolName);
1044       else
1045         addRelocationForSection(RE, Value.SectionID);
1046       Section.StubOffset = StubOffset + getMaxStubSize();
1047     }
1048
1049     if (RelType == ELF::R_390_GOTENT)
1050       resolveRelocation(Section, Offset, StubAddress + 8,
1051                         ELF::R_390_PC32DBL, Addend);
1052     else
1053       resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1054   } else {
1055     RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1056     if (Value.SymbolName)
1057       addRelocationForSymbol(RE, Value.SymbolName);
1058     else
1059       addRelocationForSection(RE, Value.SectionID);
1060   }
1061 }
1062
1063 bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const {
1064   if (Buffer->getBufferSize() < strlen(ELF::ElfMagic))
1065     return false;
1066   return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
1067 }
1068 } // namespace llvm