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 #include "RuntimeDyldELF.h" 15 #include "RuntimeDyldCheckerImpl.h" 16 #include "Targets/RuntimeDyldELFMips.h" 17 #include "llvm/ADT/STLExtras.h" 18 #include "llvm/ADT/StringRef.h" 19 #include "llvm/ADT/Triple.h" 20 #include "llvm/BinaryFormat/ELF.h" 21 #include "llvm/Object/ELFObjectFile.h" 22 #include "llvm/Object/ObjectFile.h" 23 #include "llvm/Support/Endian.h" 24 #include "llvm/Support/MemoryBuffer.h" 25 26 using namespace llvm; 27 using namespace llvm::object; 28 using namespace llvm::support::endian; 29 30 #define DEBUG_TYPE "dyld" 31 32 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); } 33 34 static void or32AArch64Imm(void *L, uint64_t Imm) { 35 or32le(L, (Imm & 0xFFF) << 10); 36 } 37 38 template <class T> static void write(bool isBE, void *P, T V) { 39 isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V); 40 } 41 42 static void write32AArch64Addr(void *L, uint64_t Imm) { 43 uint32_t ImmLo = (Imm & 0x3) << 29; 44 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 45 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 46 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 47 } 48 49 // Return the bits [Start, End] from Val shifted Start bits. 50 // For instance, getBits(0xF0, 4, 8) returns 0xF. 51 static uint64_t getBits(uint64_t Val, int Start, int End) { 52 uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1; 53 return (Val >> Start) & Mask; 54 } 55 56 namespace { 57 58 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> { 59 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) 60 61 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr; 62 typedef Elf_Sym_Impl<ELFT> Elf_Sym; 63 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel; 64 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela; 65 66 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; 67 68 typedef typename ELFT::uint addr_type; 69 70 DyldELFObject(ELFObjectFile<ELFT> &&Obj); 71 72 public: 73 static Expected<std::unique_ptr<DyldELFObject>> 74 create(MemoryBufferRef Wrapper); 75 76 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 77 78 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); 79 80 // Methods for type inquiry through isa, cast and dyn_cast 81 static bool classof(const Binary *v) { 82 return (isa<ELFObjectFile<ELFT>>(v) && 83 classof(cast<ELFObjectFile<ELFT>>(v))); 84 } 85 static bool classof(const ELFObjectFile<ELFT> *v) { 86 return v->isDyldType(); 87 } 88 }; 89 90 91 92 // The MemoryBuffer passed into this constructor is just a wrapper around the 93 // actual memory. Ultimately, the Binary parent class will take ownership of 94 // this MemoryBuffer object but not the underlying memory. 95 template <class ELFT> 96 DyldELFObject<ELFT>::DyldELFObject(ELFObjectFile<ELFT> &&Obj) 97 : ELFObjectFile<ELFT>(std::move(Obj)) { 98 this->isDyldELFObject = true; 99 } 100 101 template <class ELFT> 102 Expected<std::unique_ptr<DyldELFObject<ELFT>>> 103 DyldELFObject<ELFT>::create(MemoryBufferRef Wrapper) { 104 auto Obj = ELFObjectFile<ELFT>::create(Wrapper); 105 if (auto E = Obj.takeError()) 106 return std::move(E); 107 std::unique_ptr<DyldELFObject<ELFT>> Ret( 108 new DyldELFObject<ELFT>(std::move(*Obj))); 109 return std::move(Ret); 110 } 111 112 template <class ELFT> 113 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 114 uint64_t Addr) { 115 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 116 Elf_Shdr *shdr = 117 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 118 119 // This assumes the address passed in matches the target address bitness 120 // The template-based type cast handles everything else. 121 shdr->sh_addr = static_cast<addr_type>(Addr); 122 } 123 124 template <class ELFT> 125 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 126 uint64_t Addr) { 127 128 Elf_Sym *sym = const_cast<Elf_Sym *>( 129 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 130 131 // This assumes the address passed in matches the target address bitness 132 // The template-based type cast handles everything else. 133 sym->st_value = static_cast<addr_type>(Addr); 134 } 135 136 class LoadedELFObjectInfo final 137 : public LoadedObjectInfoHelper<LoadedELFObjectInfo, 138 RuntimeDyld::LoadedObjectInfo> { 139 public: 140 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap) 141 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {} 142 143 OwningBinary<ObjectFile> 144 getObjectForDebug(const ObjectFile &Obj) const override; 145 }; 146 147 template <typename ELFT> 148 static Expected<std::unique_ptr<DyldELFObject<ELFT>>> 149 createRTDyldELFObject(MemoryBufferRef Buffer, const ObjectFile &SourceObject, 150 const LoadedELFObjectInfo &L) { 151 typedef typename ELFT::Shdr Elf_Shdr; 152 typedef typename ELFT::uint addr_type; 153 154 Expected<std::unique_ptr<DyldELFObject<ELFT>>> ObjOrErr = 155 DyldELFObject<ELFT>::create(Buffer); 156 if (Error E = ObjOrErr.takeError()) 157 return std::move(E); 158 159 std::unique_ptr<DyldELFObject<ELFT>> Obj = std::move(*ObjOrErr); 160 161 // Iterate over all sections in the object. 162 auto SI = SourceObject.section_begin(); 163 for (const auto &Sec : Obj->sections()) { 164 StringRef SectionName; 165 Sec.getName(SectionName); 166 if (SectionName != "") { 167 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 168 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 169 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 170 171 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { 172 // This assumes that the address passed in matches the target address 173 // bitness. The template-based type cast handles everything else. 174 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 175 } 176 } 177 ++SI; 178 } 179 180 return std::move(Obj); 181 } 182 183 static OwningBinary<ObjectFile> 184 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) { 185 assert(Obj.isELF() && "Not an ELF object file."); 186 187 std::unique_ptr<MemoryBuffer> Buffer = 188 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 189 190 Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr); 191 handleAllErrors(DebugObj.takeError()); 192 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) 193 DebugObj = 194 createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L); 195 else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) 196 DebugObj = 197 createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L); 198 else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) 199 DebugObj = 200 createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L); 201 else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) 202 DebugObj = 203 createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L); 204 else 205 llvm_unreachable("Unexpected ELF format"); 206 207 handleAllErrors(DebugObj.takeError()); 208 return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer)); 209 } 210 211 OwningBinary<ObjectFile> 212 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 213 return createELFDebugObject(Obj, *this); 214 } 215 216 } // anonymous namespace 217 218 namespace llvm { 219 220 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 221 JITSymbolResolver &Resolver) 222 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 223 RuntimeDyldELF::~RuntimeDyldELF() {} 224 225 void RuntimeDyldELF::registerEHFrames() { 226 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { 227 SID EHFrameSID = UnregisteredEHFrameSections[i]; 228 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 229 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 230 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 231 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 232 } 233 UnregisteredEHFrameSections.clear(); 234 } 235 236 std::unique_ptr<RuntimeDyldELF> 237 llvm::RuntimeDyldELF::create(Triple::ArchType Arch, 238 RuntimeDyld::MemoryManager &MemMgr, 239 JITSymbolResolver &Resolver) { 240 switch (Arch) { 241 default: 242 return make_unique<RuntimeDyldELF>(MemMgr, Resolver); 243 case Triple::mips: 244 case Triple::mipsel: 245 case Triple::mips64: 246 case Triple::mips64el: 247 return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); 248 } 249 } 250 251 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 252 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 253 if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) 254 return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); 255 else { 256 HasError = true; 257 raw_string_ostream ErrStream(ErrorStr); 258 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, ""); 259 return nullptr; 260 } 261 } 262 263 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 264 uint64_t Offset, uint64_t Value, 265 uint32_t Type, int64_t Addend, 266 uint64_t SymOffset) { 267 switch (Type) { 268 default: 269 llvm_unreachable("Relocation type not implemented yet!"); 270 break; 271 case ELF::R_X86_64_NONE: 272 break; 273 case ELF::R_X86_64_64: { 274 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 275 Value + Addend; 276 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 277 << format("%p\n", Section.getAddressWithOffset(Offset))); 278 break; 279 } 280 case ELF::R_X86_64_32: 281 case ELF::R_X86_64_32S: { 282 Value += Addend; 283 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 284 (Type == ELF::R_X86_64_32S && 285 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 286 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 287 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 288 TruncatedAddr; 289 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 290 << format("%p\n", Section.getAddressWithOffset(Offset))); 291 break; 292 } 293 case ELF::R_X86_64_PC8: { 294 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 295 int64_t RealOffset = Value + Addend - FinalAddress; 296 assert(isInt<8>(RealOffset)); 297 int8_t TruncOffset = (RealOffset & 0xFF); 298 Section.getAddress()[Offset] = TruncOffset; 299 break; 300 } 301 case ELF::R_X86_64_PC32: { 302 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 303 int64_t RealOffset = Value + Addend - FinalAddress; 304 assert(isInt<32>(RealOffset)); 305 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 306 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 307 TruncOffset; 308 break; 309 } 310 case ELF::R_X86_64_PC64: { 311 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 312 int64_t RealOffset = Value + Addend - FinalAddress; 313 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 314 RealOffset; 315 break; 316 } 317 } 318 } 319 320 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 321 uint64_t Offset, uint32_t Value, 322 uint32_t Type, int32_t Addend) { 323 switch (Type) { 324 case ELF::R_386_32: { 325 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 326 Value + Addend; 327 break; 328 } 329 // Handle R_386_PLT32 like R_386_PC32 since it should be able to 330 // reach any 32 bit address. 331 case ELF::R_386_PLT32: 332 case ELF::R_386_PC32: { 333 uint32_t FinalAddress = 334 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 335 uint32_t RealOffset = Value + Addend - FinalAddress; 336 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 337 RealOffset; 338 break; 339 } 340 default: 341 // There are other relocation types, but it appears these are the 342 // only ones currently used by the LLVM ELF object writer 343 llvm_unreachable("Relocation type not implemented yet!"); 344 break; 345 } 346 } 347 348 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 349 uint64_t Offset, uint64_t Value, 350 uint32_t Type, int64_t Addend) { 351 uint32_t *TargetPtr = 352 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 353 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 354 // Data should use target endian. Code should always use little endian. 355 bool isBE = Arch == Triple::aarch64_be; 356 357 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 358 << format("%llx", Section.getAddressWithOffset(Offset)) 359 << " FinalAddress: 0x" << format("%llx", FinalAddress) 360 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 361 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend) 362 << "\n"); 363 364 switch (Type) { 365 default: 366 llvm_unreachable("Relocation type not implemented yet!"); 367 break; 368 case ELF::R_AARCH64_ABS16: { 369 uint64_t Result = Value + Addend; 370 assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX); 371 write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU)); 372 break; 373 } 374 case ELF::R_AARCH64_ABS32: { 375 uint64_t Result = Value + Addend; 376 assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX); 377 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 378 break; 379 } 380 case ELF::R_AARCH64_ABS64: 381 write(isBE, TargetPtr, Value + Addend); 382 break; 383 case ELF::R_AARCH64_PREL32: { 384 uint64_t Result = Value + Addend - FinalAddress; 385 assert(static_cast<int64_t>(Result) >= INT32_MIN && 386 static_cast<int64_t>(Result) <= UINT32_MAX); 387 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 388 break; 389 } 390 case ELF::R_AARCH64_PREL64: 391 write(isBE, TargetPtr, Value + Addend - FinalAddress); 392 break; 393 case ELF::R_AARCH64_CALL26: // fallthrough 394 case ELF::R_AARCH64_JUMP26: { 395 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 396 // calculation. 397 uint64_t BranchImm = Value + Addend - FinalAddress; 398 399 // "Check that -2^27 <= result < 2^27". 400 assert(isInt<28>(BranchImm)); 401 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 402 break; 403 } 404 case ELF::R_AARCH64_MOVW_UABS_G3: 405 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 406 break; 407 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 408 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 409 break; 410 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 411 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 412 break; 413 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 414 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 415 break; 416 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 417 // Operation: Page(S+A) - Page(P) 418 uint64_t Result = 419 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 420 421 // Check that -2^32 <= X < 2^32 422 assert(isInt<33>(Result) && "overflow check failed for relocation"); 423 424 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 425 // from bits 32:12 of X. 426 write32AArch64Addr(TargetPtr, Result >> 12); 427 break; 428 } 429 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 430 // Operation: S + A 431 // Immediate goes in bits 21:10 of LD/ST instruction, taken 432 // from bits 11:0 of X 433 or32AArch64Imm(TargetPtr, Value + Addend); 434 break; 435 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 436 // Operation: S + A 437 // Immediate goes in bits 21:10 of LD/ST instruction, taken 438 // from bits 11:0 of X 439 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 440 break; 441 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 442 // Operation: S + A 443 // Immediate goes in bits 21:10 of LD/ST instruction, taken 444 // from bits 11:1 of X 445 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 446 break; 447 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 448 // Operation: S + A 449 // Immediate goes in bits 21:10 of LD/ST instruction, taken 450 // from bits 11:2 of X 451 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 452 break; 453 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 454 // Operation: S + A 455 // Immediate goes in bits 21:10 of LD/ST instruction, taken 456 // from bits 11:3 of X 457 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 458 break; 459 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 460 // Operation: S + A 461 // Immediate goes in bits 21:10 of LD/ST instruction, taken 462 // from bits 11:4 of X 463 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 464 break; 465 } 466 } 467 468 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 469 uint64_t Offset, uint32_t Value, 470 uint32_t Type, int32_t Addend) { 471 // TODO: Add Thumb relocations. 472 uint32_t *TargetPtr = 473 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 474 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 475 Value += Addend; 476 477 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 478 << Section.getAddressWithOffset(Offset) 479 << " FinalAddress: " << format("%p", FinalAddress) << " Value: " 480 << format("%x", Value) << " Type: " << format("%x", Type) 481 << " Addend: " << format("%x", Addend) << "\n"); 482 483 switch (Type) { 484 default: 485 llvm_unreachable("Not implemented relocation type!"); 486 487 case ELF::R_ARM_NONE: 488 break; 489 // Write a 31bit signed offset 490 case ELF::R_ARM_PREL31: 491 support::ulittle32_t::ref{TargetPtr} = 492 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 493 ((Value - FinalAddress) & ~0x80000000); 494 break; 495 case ELF::R_ARM_TARGET1: 496 case ELF::R_ARM_ABS32: 497 support::ulittle32_t::ref{TargetPtr} = Value; 498 break; 499 // Write first 16 bit of 32 bit value to the mov instruction. 500 // Last 4 bit should be shifted. 501 case ELF::R_ARM_MOVW_ABS_NC: 502 case ELF::R_ARM_MOVT_ABS: 503 if (Type == ELF::R_ARM_MOVW_ABS_NC) 504 Value = Value & 0xFFFF; 505 else if (Type == ELF::R_ARM_MOVT_ABS) 506 Value = (Value >> 16) & 0xFFFF; 507 support::ulittle32_t::ref{TargetPtr} = 508 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 509 (((Value >> 12) & 0xF) << 16); 510 break; 511 // Write 24 bit relative value to the branch instruction. 512 case ELF::R_ARM_PC24: // Fall through. 513 case ELF::R_ARM_CALL: // Fall through. 514 case ELF::R_ARM_JUMP24: 515 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 516 RelValue = (RelValue & 0x03FFFFFC) >> 2; 517 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 518 support::ulittle32_t::ref{TargetPtr} = 519 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 520 break; 521 } 522 } 523 524 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 525 if (Arch == Triple::UnknownArch || 526 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 527 IsMipsO32ABI = false; 528 IsMipsN32ABI = false; 529 IsMipsN64ABI = false; 530 return; 531 } 532 unsigned AbiVariant; 533 Obj.getPlatformFlags(AbiVariant); 534 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 535 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 536 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); 537 } 538 539 // Return the .TOC. section and offset. 540 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 541 ObjSectionToIDMap &LocalSections, 542 RelocationValueRef &Rel) { 543 // Set a default SectionID in case we do not find a TOC section below. 544 // This may happen for references to TOC base base (sym@toc, .odp 545 // relocation) without a .toc directive. In this case just use the 546 // first section (which is usually the .odp) since the code won't 547 // reference the .toc base directly. 548 Rel.SymbolName = nullptr; 549 Rel.SectionID = 0; 550 551 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 552 // order. The TOC starts where the first of these sections starts. 553 for (auto &Section: Obj.sections()) { 554 StringRef SectionName; 555 if (auto EC = Section.getName(SectionName)) 556 return errorCodeToError(EC); 557 558 if (SectionName == ".got" 559 || SectionName == ".toc" 560 || SectionName == ".tocbss" 561 || SectionName == ".plt") { 562 if (auto SectionIDOrErr = 563 findOrEmitSection(Obj, Section, false, LocalSections)) 564 Rel.SectionID = *SectionIDOrErr; 565 else 566 return SectionIDOrErr.takeError(); 567 break; 568 } 569 } 570 571 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 572 // thus permitting a full 64 Kbytes segment. 573 Rel.Addend = 0x8000; 574 575 return Error::success(); 576 } 577 578 // Returns the sections and offset associated with the ODP entry referenced 579 // by Symbol. 580 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 581 ObjSectionToIDMap &LocalSections, 582 RelocationValueRef &Rel) { 583 // Get the ELF symbol value (st_value) to compare with Relocation offset in 584 // .opd entries 585 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 586 si != se; ++si) { 587 section_iterator RelSecI = si->getRelocatedSection(); 588 if (RelSecI == Obj.section_end()) 589 continue; 590 591 StringRef RelSectionName; 592 if (auto EC = RelSecI->getName(RelSectionName)) 593 return errorCodeToError(EC); 594 595 if (RelSectionName != ".opd") 596 continue; 597 598 for (elf_relocation_iterator i = si->relocation_begin(), 599 e = si->relocation_end(); 600 i != e;) { 601 // The R_PPC64_ADDR64 relocation indicates the first field 602 // of a .opd entry 603 uint64_t TypeFunc = i->getType(); 604 if (TypeFunc != ELF::R_PPC64_ADDR64) { 605 ++i; 606 continue; 607 } 608 609 uint64_t TargetSymbolOffset = i->getOffset(); 610 symbol_iterator TargetSymbol = i->getSymbol(); 611 int64_t Addend; 612 if (auto AddendOrErr = i->getAddend()) 613 Addend = *AddendOrErr; 614 else 615 return AddendOrErr.takeError(); 616 617 ++i; 618 if (i == e) 619 break; 620 621 // Just check if following relocation is a R_PPC64_TOC 622 uint64_t TypeTOC = i->getType(); 623 if (TypeTOC != ELF::R_PPC64_TOC) 624 continue; 625 626 // Finally compares the Symbol value and the target symbol offset 627 // to check if this .opd entry refers to the symbol the relocation 628 // points to. 629 if (Rel.Addend != (int64_t)TargetSymbolOffset) 630 continue; 631 632 section_iterator TSI = Obj.section_end(); 633 if (auto TSIOrErr = TargetSymbol->getSection()) 634 TSI = *TSIOrErr; 635 else 636 return TSIOrErr.takeError(); 637 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 638 639 bool IsCode = TSI->isText(); 640 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 641 LocalSections)) 642 Rel.SectionID = *SectionIDOrErr; 643 else 644 return SectionIDOrErr.takeError(); 645 Rel.Addend = (intptr_t)Addend; 646 return Error::success(); 647 } 648 } 649 llvm_unreachable("Attempting to get address of ODP entry!"); 650 } 651 652 // Relocation masks following the #lo(value), #hi(value), #ha(value), 653 // #higher(value), #highera(value), #highest(value), and #highesta(value) 654 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 655 // document. 656 657 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 658 659 static inline uint16_t applyPPChi(uint64_t value) { 660 return (value >> 16) & 0xffff; 661 } 662 663 static inline uint16_t applyPPCha (uint64_t value) { 664 return ((value + 0x8000) >> 16) & 0xffff; 665 } 666 667 static inline uint16_t applyPPChigher(uint64_t value) { 668 return (value >> 32) & 0xffff; 669 } 670 671 static inline uint16_t applyPPChighera (uint64_t value) { 672 return ((value + 0x8000) >> 32) & 0xffff; 673 } 674 675 static inline uint16_t applyPPChighest(uint64_t value) { 676 return (value >> 48) & 0xffff; 677 } 678 679 static inline uint16_t applyPPChighesta (uint64_t value) { 680 return ((value + 0x8000) >> 48) & 0xffff; 681 } 682 683 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 684 uint64_t Offset, uint64_t Value, 685 uint32_t Type, int64_t Addend) { 686 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 687 switch (Type) { 688 default: 689 llvm_unreachable("Relocation type not implemented yet!"); 690 break; 691 case ELF::R_PPC_ADDR16_LO: 692 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 693 break; 694 case ELF::R_PPC_ADDR16_HI: 695 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 696 break; 697 case ELF::R_PPC_ADDR16_HA: 698 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 699 break; 700 } 701 } 702 703 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 704 uint64_t Offset, uint64_t Value, 705 uint32_t Type, int64_t Addend) { 706 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 707 switch (Type) { 708 default: 709 llvm_unreachable("Relocation type not implemented yet!"); 710 break; 711 case ELF::R_PPC64_ADDR16: 712 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 713 break; 714 case ELF::R_PPC64_ADDR16_DS: 715 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 716 break; 717 case ELF::R_PPC64_ADDR16_LO: 718 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 719 break; 720 case ELF::R_PPC64_ADDR16_LO_DS: 721 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 722 break; 723 case ELF::R_PPC64_ADDR16_HI: 724 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 725 break; 726 case ELF::R_PPC64_ADDR16_HA: 727 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 728 break; 729 case ELF::R_PPC64_ADDR16_HIGHER: 730 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 731 break; 732 case ELF::R_PPC64_ADDR16_HIGHERA: 733 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 734 break; 735 case ELF::R_PPC64_ADDR16_HIGHEST: 736 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 737 break; 738 case ELF::R_PPC64_ADDR16_HIGHESTA: 739 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 740 break; 741 case ELF::R_PPC64_ADDR14: { 742 assert(((Value + Addend) & 3) == 0); 743 // Preserve the AA/LK bits in the branch instruction 744 uint8_t aalk = *(LocalAddress + 3); 745 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 746 } break; 747 case ELF::R_PPC64_REL16_LO: { 748 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 749 uint64_t Delta = Value - FinalAddress + Addend; 750 writeInt16BE(LocalAddress, applyPPClo(Delta)); 751 } break; 752 case ELF::R_PPC64_REL16_HI: { 753 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 754 uint64_t Delta = Value - FinalAddress + Addend; 755 writeInt16BE(LocalAddress, applyPPChi(Delta)); 756 } break; 757 case ELF::R_PPC64_REL16_HA: { 758 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 759 uint64_t Delta = Value - FinalAddress + Addend; 760 writeInt16BE(LocalAddress, applyPPCha(Delta)); 761 } break; 762 case ELF::R_PPC64_ADDR32: { 763 int64_t Result = static_cast<int64_t>(Value + Addend); 764 if (SignExtend64<32>(Result) != Result) 765 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 766 writeInt32BE(LocalAddress, Result); 767 } break; 768 case ELF::R_PPC64_REL24: { 769 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 770 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 771 if (SignExtend64<26>(delta) != delta) 772 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 773 // Generates a 'bl <address>' instruction 774 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); 775 } break; 776 case ELF::R_PPC64_REL32: { 777 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 778 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 779 if (SignExtend64<32>(delta) != delta) 780 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 781 writeInt32BE(LocalAddress, delta); 782 } break; 783 case ELF::R_PPC64_REL64: { 784 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 785 uint64_t Delta = Value - FinalAddress + Addend; 786 writeInt64BE(LocalAddress, Delta); 787 } break; 788 case ELF::R_PPC64_ADDR64: 789 writeInt64BE(LocalAddress, Value + Addend); 790 break; 791 } 792 } 793 794 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 795 uint64_t Offset, uint64_t Value, 796 uint32_t Type, int64_t Addend) { 797 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 798 switch (Type) { 799 default: 800 llvm_unreachable("Relocation type not implemented yet!"); 801 break; 802 case ELF::R_390_PC16DBL: 803 case ELF::R_390_PLT16DBL: { 804 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 805 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 806 writeInt16BE(LocalAddress, Delta / 2); 807 break; 808 } 809 case ELF::R_390_PC32DBL: 810 case ELF::R_390_PLT32DBL: { 811 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 812 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 813 writeInt32BE(LocalAddress, Delta / 2); 814 break; 815 } 816 case ELF::R_390_PC16: { 817 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 818 assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); 819 writeInt16BE(LocalAddress, Delta); 820 break; 821 } 822 case ELF::R_390_PC32: { 823 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 824 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 825 writeInt32BE(LocalAddress, Delta); 826 break; 827 } 828 case ELF::R_390_PC64: { 829 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 830 writeInt64BE(LocalAddress, Delta); 831 break; 832 } 833 case ELF::R_390_8: 834 *LocalAddress = (uint8_t)(Value + Addend); 835 break; 836 case ELF::R_390_16: 837 writeInt16BE(LocalAddress, Value + Addend); 838 break; 839 case ELF::R_390_32: 840 writeInt32BE(LocalAddress, Value + Addend); 841 break; 842 case ELF::R_390_64: 843 writeInt64BE(LocalAddress, Value + Addend); 844 break; 845 } 846 } 847 848 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 849 uint64_t Offset, uint64_t Value, 850 uint32_t Type, int64_t Addend) { 851 bool isBE = Arch == Triple::bpfeb; 852 853 switch (Type) { 854 default: 855 llvm_unreachable("Relocation type not implemented yet!"); 856 break; 857 case ELF::R_BPF_NONE: 858 break; 859 case ELF::R_BPF_64_64: { 860 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 861 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 862 << format("%p\n", Section.getAddressWithOffset(Offset))); 863 break; 864 } 865 case ELF::R_BPF_64_32: { 866 Value += Addend; 867 assert(Value <= UINT32_MAX); 868 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 869 DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 870 << format("%p\n", Section.getAddressWithOffset(Offset))); 871 break; 872 } 873 } 874 } 875 876 // The target location for the relocation is described by RE.SectionID and 877 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 878 // SectionEntry has three members describing its location. 879 // SectionEntry::Address is the address at which the section has been loaded 880 // into memory in the current (host) process. SectionEntry::LoadAddress is the 881 // address that the section will have in the target process. 882 // SectionEntry::ObjAddress is the address of the bits for this section in the 883 // original emitted object image (also in the current address space). 884 // 885 // Relocations will be applied as if the section were loaded at 886 // SectionEntry::LoadAddress, but they will be applied at an address based 887 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 888 // Target memory contents if they are required for value calculations. 889 // 890 // The Value parameter here is the load address of the symbol for the 891 // relocation to be applied. For relocations which refer to symbols in the 892 // current object Value will be the LoadAddress of the section in which 893 // the symbol resides (RE.Addend provides additional information about the 894 // symbol location). For external symbols, Value will be the address of the 895 // symbol in the target address space. 896 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 897 uint64_t Value) { 898 const SectionEntry &Section = Sections[RE.SectionID]; 899 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 900 RE.SymOffset, RE.SectionID); 901 } 902 903 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 904 uint64_t Offset, uint64_t Value, 905 uint32_t Type, int64_t Addend, 906 uint64_t SymOffset, SID SectionID) { 907 switch (Arch) { 908 case Triple::x86_64: 909 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 910 break; 911 case Triple::x86: 912 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 913 (uint32_t)(Addend & 0xffffffffL)); 914 break; 915 case Triple::aarch64: 916 case Triple::aarch64_be: 917 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 918 break; 919 case Triple::arm: // Fall through. 920 case Triple::armeb: 921 case Triple::thumb: 922 case Triple::thumbeb: 923 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 924 (uint32_t)(Addend & 0xffffffffL)); 925 break; 926 case Triple::ppc: 927 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 928 break; 929 case Triple::ppc64: // Fall through. 930 case Triple::ppc64le: 931 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 932 break; 933 case Triple::systemz: 934 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 935 break; 936 case Triple::bpfel: 937 case Triple::bpfeb: 938 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 939 break; 940 default: 941 llvm_unreachable("Unsupported CPU type!"); 942 } 943 } 944 945 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 946 return (void *)(Sections[SectionID].getObjAddress() + Offset); 947 } 948 949 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 950 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 951 if (Value.SymbolName) 952 addRelocationForSymbol(RE, Value.SymbolName); 953 else 954 addRelocationForSection(RE, Value.SectionID); 955 } 956 957 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 958 bool IsLocal) const { 959 switch (RelType) { 960 case ELF::R_MICROMIPS_GOT16: 961 if (IsLocal) 962 return ELF::R_MICROMIPS_LO16; 963 break; 964 case ELF::R_MICROMIPS_HI16: 965 return ELF::R_MICROMIPS_LO16; 966 case ELF::R_MIPS_GOT16: 967 if (IsLocal) 968 return ELF::R_MIPS_LO16; 969 break; 970 case ELF::R_MIPS_HI16: 971 return ELF::R_MIPS_LO16; 972 case ELF::R_MIPS_PCHI16: 973 return ELF::R_MIPS_PCLO16; 974 default: 975 break; 976 } 977 return ELF::R_MIPS_NONE; 978 } 979 980 // Sometimes we don't need to create thunk for a branch. 981 // This typically happens when branch target is located 982 // in the same object file. In such case target is either 983 // a weak symbol or symbol in a different executable section. 984 // This function checks if branch target is located in the 985 // same object file and if distance between source and target 986 // fits R_AARCH64_CALL26 relocation. If both conditions are 987 // met, it emits direct jump to the target and returns true. 988 // Otherwise false is returned and thunk is created. 989 bool RuntimeDyldELF::resolveAArch64ShortBranch( 990 unsigned SectionID, relocation_iterator RelI, 991 const RelocationValueRef &Value) { 992 uint64_t Address; 993 if (Value.SymbolName) { 994 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 995 996 // Don't create direct branch for external symbols. 997 if (Loc == GlobalSymbolTable.end()) 998 return false; 999 1000 const auto &SymInfo = Loc->second; 1001 Address = 1002 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 1003 SymInfo.getOffset())); 1004 } else { 1005 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 1006 } 1007 uint64_t Offset = RelI->getOffset(); 1008 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 1009 1010 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 1011 // If distance between source and target is out of range then we should 1012 // create thunk. 1013 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 1014 return false; 1015 1016 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 1017 Value.Addend); 1018 1019 return true; 1020 } 1021 1022 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 1023 const RelocationValueRef &Value, 1024 relocation_iterator RelI, 1025 StubMap &Stubs) { 1026 1027 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1028 SectionEntry &Section = Sections[SectionID]; 1029 1030 uint64_t Offset = RelI->getOffset(); 1031 unsigned RelType = RelI->getType(); 1032 // Look for an existing stub. 1033 StubMap::const_iterator i = Stubs.find(Value); 1034 if (i != Stubs.end()) { 1035 resolveRelocation(Section, Offset, 1036 (uint64_t)Section.getAddressWithOffset(i->second), 1037 RelType, 0); 1038 DEBUG(dbgs() << " Stub function found\n"); 1039 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1040 // Create a new stub function. 1041 DEBUG(dbgs() << " Create a new stub function\n"); 1042 Stubs[Value] = Section.getStubOffset(); 1043 uint8_t *StubTargetAddr = createStubFunction( 1044 Section.getAddressWithOffset(Section.getStubOffset())); 1045 1046 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1047 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1048 RelocationEntry REmovk_g2(SectionID, 1049 StubTargetAddr - Section.getAddress() + 4, 1050 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1051 RelocationEntry REmovk_g1(SectionID, 1052 StubTargetAddr - Section.getAddress() + 8, 1053 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1054 RelocationEntry REmovk_g0(SectionID, 1055 StubTargetAddr - Section.getAddress() + 12, 1056 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1057 1058 if (Value.SymbolName) { 1059 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1060 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1061 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1062 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1063 } else { 1064 addRelocationForSection(REmovz_g3, Value.SectionID); 1065 addRelocationForSection(REmovk_g2, Value.SectionID); 1066 addRelocationForSection(REmovk_g1, Value.SectionID); 1067 addRelocationForSection(REmovk_g0, Value.SectionID); 1068 } 1069 resolveRelocation(Section, Offset, 1070 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1071 Section.getStubOffset())), 1072 RelType, 0); 1073 Section.advanceStubOffset(getMaxStubSize()); 1074 } 1075 } 1076 1077 Expected<relocation_iterator> 1078 RuntimeDyldELF::processRelocationRef( 1079 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1080 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1081 const auto &Obj = cast<ELFObjectFileBase>(O); 1082 uint64_t RelType = RelI->getType(); 1083 int64_t Addend = 0; 1084 if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend()) 1085 Addend = *AddendOrErr; 1086 else 1087 consumeError(AddendOrErr.takeError()); 1088 elf_symbol_iterator Symbol = RelI->getSymbol(); 1089 1090 // Obtain the symbol name which is referenced in the relocation 1091 StringRef TargetName; 1092 if (Symbol != Obj.symbol_end()) { 1093 if (auto TargetNameOrErr = Symbol->getName()) 1094 TargetName = *TargetNameOrErr; 1095 else 1096 return TargetNameOrErr.takeError(); 1097 } 1098 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1099 << " TargetName: " << TargetName << "\n"); 1100 RelocationValueRef Value; 1101 // First search for the symbol in the local symbol table 1102 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1103 1104 // Search for the symbol in the global symbol table 1105 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1106 if (Symbol != Obj.symbol_end()) { 1107 gsi = GlobalSymbolTable.find(TargetName.data()); 1108 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1109 if (!SymTypeOrErr) { 1110 std::string Buf; 1111 raw_string_ostream OS(Buf); 1112 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, ""); 1113 OS.flush(); 1114 report_fatal_error(Buf); 1115 } 1116 SymType = *SymTypeOrErr; 1117 } 1118 if (gsi != GlobalSymbolTable.end()) { 1119 const auto &SymInfo = gsi->second; 1120 Value.SectionID = SymInfo.getSectionID(); 1121 Value.Offset = SymInfo.getOffset(); 1122 Value.Addend = SymInfo.getOffset() + Addend; 1123 } else { 1124 switch (SymType) { 1125 case SymbolRef::ST_Debug: { 1126 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1127 // and can be changed by another developers. Maybe best way is add 1128 // a new symbol type ST_Section to SymbolRef and use it. 1129 auto SectionOrErr = Symbol->getSection(); 1130 if (!SectionOrErr) { 1131 std::string Buf; 1132 raw_string_ostream OS(Buf); 1133 logAllUnhandledErrors(SectionOrErr.takeError(), OS, ""); 1134 OS.flush(); 1135 report_fatal_error(Buf); 1136 } 1137 section_iterator si = *SectionOrErr; 1138 if (si == Obj.section_end()) 1139 llvm_unreachable("Symbol section not found, bad object file format!"); 1140 DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1141 bool isCode = si->isText(); 1142 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1143 ObjSectionToID)) 1144 Value.SectionID = *SectionIDOrErr; 1145 else 1146 return SectionIDOrErr.takeError(); 1147 Value.Addend = Addend; 1148 break; 1149 } 1150 case SymbolRef::ST_Data: 1151 case SymbolRef::ST_Function: 1152 case SymbolRef::ST_Unknown: { 1153 Value.SymbolName = TargetName.data(); 1154 Value.Addend = Addend; 1155 1156 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1157 // will manifest here as a NULL symbol name. 1158 // We can set this as a valid (but empty) symbol name, and rely 1159 // on addRelocationForSymbol to handle this. 1160 if (!Value.SymbolName) 1161 Value.SymbolName = ""; 1162 break; 1163 } 1164 default: 1165 llvm_unreachable("Unresolved symbol type!"); 1166 break; 1167 } 1168 } 1169 1170 uint64_t Offset = RelI->getOffset(); 1171 1172 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1173 << "\n"); 1174 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1175 if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { 1176 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1177 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1178 // Craete new GOT entry or find existing one. If GOT entry is 1179 // to be created, then we also emit ABS64 relocation for it. 1180 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1181 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1182 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1183 1184 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1185 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1186 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1187 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1188 } else { 1189 processSimpleRelocation(SectionID, Offset, RelType, Value); 1190 } 1191 } else if (Arch == Triple::arm) { 1192 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1193 RelType == ELF::R_ARM_JUMP24) { 1194 // This is an ARM branch relocation, need to use a stub function. 1195 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1196 SectionEntry &Section = Sections[SectionID]; 1197 1198 // Look for an existing stub. 1199 StubMap::const_iterator i = Stubs.find(Value); 1200 if (i != Stubs.end()) { 1201 resolveRelocation( 1202 Section, Offset, 1203 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1204 RelType, 0); 1205 DEBUG(dbgs() << " Stub function found\n"); 1206 } else { 1207 // Create a new stub function. 1208 DEBUG(dbgs() << " Create a new stub function\n"); 1209 Stubs[Value] = Section.getStubOffset(); 1210 uint8_t *StubTargetAddr = createStubFunction( 1211 Section.getAddressWithOffset(Section.getStubOffset())); 1212 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1213 ELF::R_ARM_ABS32, Value.Addend); 1214 if (Value.SymbolName) 1215 addRelocationForSymbol(RE, Value.SymbolName); 1216 else 1217 addRelocationForSection(RE, Value.SectionID); 1218 1219 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1220 Section.getAddressWithOffset( 1221 Section.getStubOffset())), 1222 RelType, 0); 1223 Section.advanceStubOffset(getMaxStubSize()); 1224 } 1225 } else { 1226 uint32_t *Placeholder = 1227 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1228 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1229 RelType == ELF::R_ARM_ABS32) { 1230 Value.Addend += *Placeholder; 1231 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1232 // See ELF for ARM documentation 1233 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1234 } 1235 processSimpleRelocation(SectionID, Offset, RelType, Value); 1236 } 1237 } else if (IsMipsO32ABI) { 1238 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1239 computePlaceholderAddress(SectionID, Offset)); 1240 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1241 if (RelType == ELF::R_MIPS_26) { 1242 // This is an Mips branch relocation, need to use a stub function. 1243 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1244 SectionEntry &Section = Sections[SectionID]; 1245 1246 // Extract the addend from the instruction. 1247 // We shift up by two since the Value will be down shifted again 1248 // when applying the relocation. 1249 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1250 1251 Value.Addend += Addend; 1252 1253 // Look up for existing stub. 1254 StubMap::const_iterator i = Stubs.find(Value); 1255 if (i != Stubs.end()) { 1256 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1257 addRelocationForSection(RE, SectionID); 1258 DEBUG(dbgs() << " Stub function found\n"); 1259 } else { 1260 // Create a new stub function. 1261 DEBUG(dbgs() << " Create a new stub function\n"); 1262 Stubs[Value] = Section.getStubOffset(); 1263 1264 unsigned AbiVariant; 1265 O.getPlatformFlags(AbiVariant); 1266 1267 uint8_t *StubTargetAddr = createStubFunction( 1268 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1269 1270 // Creating Hi and Lo relocations for the filled stub instructions. 1271 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1272 ELF::R_MIPS_HI16, Value.Addend); 1273 RelocationEntry RELo(SectionID, 1274 StubTargetAddr - Section.getAddress() + 4, 1275 ELF::R_MIPS_LO16, Value.Addend); 1276 1277 if (Value.SymbolName) { 1278 addRelocationForSymbol(REHi, Value.SymbolName); 1279 addRelocationForSymbol(RELo, Value.SymbolName); 1280 } else { 1281 addRelocationForSection(REHi, Value.SectionID); 1282 addRelocationForSection(RELo, Value.SectionID); 1283 } 1284 1285 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1286 addRelocationForSection(RE, SectionID); 1287 Section.advanceStubOffset(getMaxStubSize()); 1288 } 1289 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1290 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1291 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1292 PendingRelocs.push_back(std::make_pair(Value, RE)); 1293 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1294 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1295 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1296 const RelocationValueRef &MatchingValue = I->first; 1297 RelocationEntry &Reloc = I->second; 1298 if (MatchingValue == Value && 1299 RelType == getMatchingLoRelocation(Reloc.RelType) && 1300 SectionID == Reloc.SectionID) { 1301 Reloc.Addend += Addend; 1302 if (Value.SymbolName) 1303 addRelocationForSymbol(Reloc, Value.SymbolName); 1304 else 1305 addRelocationForSection(Reloc, Value.SectionID); 1306 I = PendingRelocs.erase(I); 1307 } else 1308 ++I; 1309 } 1310 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1311 if (Value.SymbolName) 1312 addRelocationForSymbol(RE, Value.SymbolName); 1313 else 1314 addRelocationForSection(RE, Value.SectionID); 1315 } else { 1316 if (RelType == ELF::R_MIPS_32) 1317 Value.Addend += Opcode; 1318 else if (RelType == ELF::R_MIPS_PC16) 1319 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1320 else if (RelType == ELF::R_MIPS_PC19_S2) 1321 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1322 else if (RelType == ELF::R_MIPS_PC21_S2) 1323 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1324 else if (RelType == ELF::R_MIPS_PC26_S2) 1325 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1326 processSimpleRelocation(SectionID, Offset, RelType, Value); 1327 } 1328 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1329 uint32_t r_type = RelType & 0xff; 1330 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1331 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1332 || r_type == ELF::R_MIPS_GOT_DISP) { 1333 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1334 if (i != GOTSymbolOffsets.end()) 1335 RE.SymOffset = i->second; 1336 else { 1337 RE.SymOffset = allocateGOTEntries(1); 1338 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1339 } 1340 if (Value.SymbolName) 1341 addRelocationForSymbol(RE, Value.SymbolName); 1342 else 1343 addRelocationForSection(RE, Value.SectionID); 1344 } else if (RelType == ELF::R_MIPS_26) { 1345 // This is an Mips branch relocation, need to use a stub function. 1346 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1347 SectionEntry &Section = Sections[SectionID]; 1348 1349 // Look up for existing stub. 1350 StubMap::const_iterator i = Stubs.find(Value); 1351 if (i != Stubs.end()) { 1352 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1353 addRelocationForSection(RE, SectionID); 1354 DEBUG(dbgs() << " Stub function found\n"); 1355 } else { 1356 // Create a new stub function. 1357 DEBUG(dbgs() << " Create a new stub function\n"); 1358 Stubs[Value] = Section.getStubOffset(); 1359 1360 unsigned AbiVariant; 1361 O.getPlatformFlags(AbiVariant); 1362 1363 uint8_t *StubTargetAddr = createStubFunction( 1364 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1365 1366 if (IsMipsN32ABI) { 1367 // Creating Hi and Lo relocations for the filled stub instructions. 1368 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1369 ELF::R_MIPS_HI16, Value.Addend); 1370 RelocationEntry RELo(SectionID, 1371 StubTargetAddr - Section.getAddress() + 4, 1372 ELF::R_MIPS_LO16, Value.Addend); 1373 if (Value.SymbolName) { 1374 addRelocationForSymbol(REHi, Value.SymbolName); 1375 addRelocationForSymbol(RELo, Value.SymbolName); 1376 } else { 1377 addRelocationForSection(REHi, Value.SectionID); 1378 addRelocationForSection(RELo, Value.SectionID); 1379 } 1380 } else { 1381 // Creating Highest, Higher, Hi and Lo relocations for the filled stub 1382 // instructions. 1383 RelocationEntry REHighest(SectionID, 1384 StubTargetAddr - Section.getAddress(), 1385 ELF::R_MIPS_HIGHEST, Value.Addend); 1386 RelocationEntry REHigher(SectionID, 1387 StubTargetAddr - Section.getAddress() + 4, 1388 ELF::R_MIPS_HIGHER, Value.Addend); 1389 RelocationEntry REHi(SectionID, 1390 StubTargetAddr - Section.getAddress() + 12, 1391 ELF::R_MIPS_HI16, Value.Addend); 1392 RelocationEntry RELo(SectionID, 1393 StubTargetAddr - Section.getAddress() + 20, 1394 ELF::R_MIPS_LO16, Value.Addend); 1395 if (Value.SymbolName) { 1396 addRelocationForSymbol(REHighest, Value.SymbolName); 1397 addRelocationForSymbol(REHigher, Value.SymbolName); 1398 addRelocationForSymbol(REHi, Value.SymbolName); 1399 addRelocationForSymbol(RELo, Value.SymbolName); 1400 } else { 1401 addRelocationForSection(REHighest, Value.SectionID); 1402 addRelocationForSection(REHigher, Value.SectionID); 1403 addRelocationForSection(REHi, Value.SectionID); 1404 addRelocationForSection(RELo, Value.SectionID); 1405 } 1406 } 1407 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1408 addRelocationForSection(RE, SectionID); 1409 Section.advanceStubOffset(getMaxStubSize()); 1410 } 1411 } else { 1412 processSimpleRelocation(SectionID, Offset, RelType, Value); 1413 } 1414 1415 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1416 if (RelType == ELF::R_PPC64_REL24) { 1417 // Determine ABI variant in use for this object. 1418 unsigned AbiVariant; 1419 Obj.getPlatformFlags(AbiVariant); 1420 AbiVariant &= ELF::EF_PPC64_ABI; 1421 // A PPC branch relocation will need a stub function if the target is 1422 // an external symbol (either Value.SymbolName is set, or SymType is 1423 // Symbol::ST_Unknown) or if the target address is not within the 1424 // signed 24-bits branch address. 1425 SectionEntry &Section = Sections[SectionID]; 1426 uint8_t *Target = Section.getAddressWithOffset(Offset); 1427 bool RangeOverflow = false; 1428 if (!Value.SymbolName && SymType != SymbolRef::ST_Unknown) { 1429 if (AbiVariant != 2) { 1430 // In the ELFv1 ABI, a function call may point to the .opd entry, 1431 // so the final symbol value is calculated based on the relocation 1432 // values in the .opd section. 1433 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1434 return std::move(Err); 1435 } else { 1436 // In the ELFv2 ABI, a function symbol may provide a local entry 1437 // point, which must be used for direct calls. 1438 uint8_t SymOther = Symbol->getOther(); 1439 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1440 } 1441 uint8_t *RelocTarget = 1442 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1443 int64_t delta = static_cast<int64_t>(Target - RelocTarget); 1444 // If it is within 26-bits branch range, just set the branch target 1445 if (SignExtend64<26>(delta) == delta) { 1446 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1447 addRelocationForSection(RE, Value.SectionID); 1448 } else { 1449 RangeOverflow = true; 1450 } 1451 } 1452 if (Value.SymbolName || SymType == SymbolRef::ST_Unknown || 1453 RangeOverflow) { 1454 // It is an external symbol (either Value.SymbolName is set, or 1455 // SymType is SymbolRef::ST_Unknown) or out of range. 1456 StubMap::const_iterator i = Stubs.find(Value); 1457 if (i != Stubs.end()) { 1458 // Symbol function stub already created, just relocate to it 1459 resolveRelocation(Section, Offset, 1460 reinterpret_cast<uint64_t>( 1461 Section.getAddressWithOffset(i->second)), 1462 RelType, 0); 1463 DEBUG(dbgs() << " Stub function found\n"); 1464 } else { 1465 // Create a new stub function. 1466 DEBUG(dbgs() << " Create a new stub function\n"); 1467 Stubs[Value] = Section.getStubOffset(); 1468 uint8_t *StubTargetAddr = createStubFunction( 1469 Section.getAddressWithOffset(Section.getStubOffset()), 1470 AbiVariant); 1471 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1472 ELF::R_PPC64_ADDR64, Value.Addend); 1473 1474 // Generates the 64-bits address loads as exemplified in section 1475 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1476 // apply to the low part of the instructions, so we have to update 1477 // the offset according to the target endianness. 1478 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1479 if (!IsTargetLittleEndian) 1480 StubRelocOffset += 2; 1481 1482 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1483 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1484 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1485 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1486 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1487 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1488 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1489 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1490 1491 if (Value.SymbolName) { 1492 addRelocationForSymbol(REhst, Value.SymbolName); 1493 addRelocationForSymbol(REhr, Value.SymbolName); 1494 addRelocationForSymbol(REh, Value.SymbolName); 1495 addRelocationForSymbol(REl, Value.SymbolName); 1496 } else { 1497 addRelocationForSection(REhst, Value.SectionID); 1498 addRelocationForSection(REhr, Value.SectionID); 1499 addRelocationForSection(REh, Value.SectionID); 1500 addRelocationForSection(REl, Value.SectionID); 1501 } 1502 1503 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1504 Section.getAddressWithOffset( 1505 Section.getStubOffset())), 1506 RelType, 0); 1507 Section.advanceStubOffset(getMaxStubSize()); 1508 } 1509 if (Value.SymbolName || SymType == SymbolRef::ST_Unknown) { 1510 // Restore the TOC for external calls 1511 if (AbiVariant == 2) 1512 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1) 1513 else 1514 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1515 } 1516 } 1517 } else if (RelType == ELF::R_PPC64_TOC16 || 1518 RelType == ELF::R_PPC64_TOC16_DS || 1519 RelType == ELF::R_PPC64_TOC16_LO || 1520 RelType == ELF::R_PPC64_TOC16_LO_DS || 1521 RelType == ELF::R_PPC64_TOC16_HI || 1522 RelType == ELF::R_PPC64_TOC16_HA) { 1523 // These relocations are supposed to subtract the TOC address from 1524 // the final value. This does not fit cleanly into the RuntimeDyld 1525 // scheme, since there may be *two* sections involved in determining 1526 // the relocation value (the section of the symbol referred to by the 1527 // relocation, and the TOC section associated with the current module). 1528 // 1529 // Fortunately, these relocations are currently only ever generated 1530 // referring to symbols that themselves reside in the TOC, which means 1531 // that the two sections are actually the same. Thus they cancel out 1532 // and we can immediately resolve the relocation right now. 1533 switch (RelType) { 1534 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1535 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1536 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1537 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1538 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1539 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1540 default: llvm_unreachable("Wrong relocation type."); 1541 } 1542 1543 RelocationValueRef TOCValue; 1544 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1545 return std::move(Err); 1546 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1547 llvm_unreachable("Unsupported TOC relocation."); 1548 Value.Addend -= TOCValue.Addend; 1549 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1550 } else { 1551 // There are two ways to refer to the TOC address directly: either 1552 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1553 // ignored), or via any relocation that refers to the magic ".TOC." 1554 // symbols (in which case the addend is respected). 1555 if (RelType == ELF::R_PPC64_TOC) { 1556 RelType = ELF::R_PPC64_ADDR64; 1557 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1558 return std::move(Err); 1559 } else if (TargetName == ".TOC.") { 1560 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1561 return std::move(Err); 1562 Value.Addend += Addend; 1563 } 1564 1565 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1566 1567 if (Value.SymbolName) 1568 addRelocationForSymbol(RE, Value.SymbolName); 1569 else 1570 addRelocationForSection(RE, Value.SectionID); 1571 } 1572 } else if (Arch == Triple::systemz && 1573 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1574 // Create function stubs for both PLT and GOT references, regardless of 1575 // whether the GOT reference is to data or code. The stub contains the 1576 // full address of the symbol, as needed by GOT references, and the 1577 // executable part only adds an overhead of 8 bytes. 1578 // 1579 // We could try to conserve space by allocating the code and data 1580 // parts of the stub separately. However, as things stand, we allocate 1581 // a stub for every relocation, so using a GOT in JIT code should be 1582 // no less space efficient than using an explicit constant pool. 1583 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1584 SectionEntry &Section = Sections[SectionID]; 1585 1586 // Look for an existing stub. 1587 StubMap::const_iterator i = Stubs.find(Value); 1588 uintptr_t StubAddress; 1589 if (i != Stubs.end()) { 1590 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1591 DEBUG(dbgs() << " Stub function found\n"); 1592 } else { 1593 // Create a new stub function. 1594 DEBUG(dbgs() << " Create a new stub function\n"); 1595 1596 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1597 uintptr_t StubAlignment = getStubAlignment(); 1598 StubAddress = 1599 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1600 -StubAlignment; 1601 unsigned StubOffset = StubAddress - BaseAddress; 1602 1603 Stubs[Value] = StubOffset; 1604 createStubFunction((uint8_t *)StubAddress); 1605 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1606 Value.Offset); 1607 if (Value.SymbolName) 1608 addRelocationForSymbol(RE, Value.SymbolName); 1609 else 1610 addRelocationForSection(RE, Value.SectionID); 1611 Section.advanceStubOffset(getMaxStubSize()); 1612 } 1613 1614 if (RelType == ELF::R_390_GOTENT) 1615 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1616 Addend); 1617 else 1618 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1619 } else if (Arch == Triple::x86_64) { 1620 if (RelType == ELF::R_X86_64_PLT32) { 1621 // The way the PLT relocations normally work is that the linker allocates 1622 // the 1623 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1624 // entry will then jump to an address provided by the GOT. On first call, 1625 // the 1626 // GOT address will point back into PLT code that resolves the symbol. After 1627 // the first call, the GOT entry points to the actual function. 1628 // 1629 // For local functions we're ignoring all of that here and just replacing 1630 // the PLT32 relocation type with PC32, which will translate the relocation 1631 // into a PC-relative call directly to the function. For external symbols we 1632 // can't be sure the function will be within 2^32 bytes of the call site, so 1633 // we need to create a stub, which calls into the GOT. This case is 1634 // equivalent to the usual PLT implementation except that we use the stub 1635 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1636 // rather than allocating a PLT section. 1637 if (Value.SymbolName) { 1638 // This is a call to an external function. 1639 // Look for an existing stub. 1640 SectionEntry &Section = Sections[SectionID]; 1641 StubMap::const_iterator i = Stubs.find(Value); 1642 uintptr_t StubAddress; 1643 if (i != Stubs.end()) { 1644 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1645 DEBUG(dbgs() << " Stub function found\n"); 1646 } else { 1647 // Create a new stub function (equivalent to a PLT entry). 1648 DEBUG(dbgs() << " Create a new stub function\n"); 1649 1650 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1651 uintptr_t StubAlignment = getStubAlignment(); 1652 StubAddress = 1653 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1654 -StubAlignment; 1655 unsigned StubOffset = StubAddress - BaseAddress; 1656 Stubs[Value] = StubOffset; 1657 createStubFunction((uint8_t *)StubAddress); 1658 1659 // Bump our stub offset counter 1660 Section.advanceStubOffset(getMaxStubSize()); 1661 1662 // Allocate a GOT Entry 1663 uint64_t GOTOffset = allocateGOTEntries(1); 1664 1665 // The load of the GOT address has an addend of -4 1666 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1667 ELF::R_X86_64_PC32); 1668 1669 // Fill in the value of the symbol we're targeting into the GOT 1670 addRelocationForSymbol( 1671 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1672 Value.SymbolName); 1673 } 1674 1675 // Make the target call a call into the stub table. 1676 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1677 Addend); 1678 } else { 1679 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1680 Value.Offset); 1681 addRelocationForSection(RE, Value.SectionID); 1682 } 1683 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1684 RelType == ELF::R_X86_64_GOTPCRELX || 1685 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1686 uint64_t GOTOffset = allocateGOTEntries(1); 1687 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1688 ELF::R_X86_64_PC32); 1689 1690 // Fill in the value of the symbol we're targeting into the GOT 1691 RelocationEntry RE = 1692 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1693 if (Value.SymbolName) 1694 addRelocationForSymbol(RE, Value.SymbolName); 1695 else 1696 addRelocationForSection(RE, Value.SectionID); 1697 } else if (RelType == ELF::R_X86_64_PC32) { 1698 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1699 processSimpleRelocation(SectionID, Offset, RelType, Value); 1700 } else if (RelType == ELF::R_X86_64_PC64) { 1701 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1702 processSimpleRelocation(SectionID, Offset, RelType, Value); 1703 } else { 1704 processSimpleRelocation(SectionID, Offset, RelType, Value); 1705 } 1706 } else { 1707 if (Arch == Triple::x86) { 1708 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1709 } 1710 processSimpleRelocation(SectionID, Offset, RelType, Value); 1711 } 1712 return ++RelI; 1713 } 1714 1715 size_t RuntimeDyldELF::getGOTEntrySize() { 1716 // We don't use the GOT in all of these cases, but it's essentially free 1717 // to put them all here. 1718 size_t Result = 0; 1719 switch (Arch) { 1720 case Triple::x86_64: 1721 case Triple::aarch64: 1722 case Triple::aarch64_be: 1723 case Triple::ppc64: 1724 case Triple::ppc64le: 1725 case Triple::systemz: 1726 Result = sizeof(uint64_t); 1727 break; 1728 case Triple::x86: 1729 case Triple::arm: 1730 case Triple::thumb: 1731 Result = sizeof(uint32_t); 1732 break; 1733 case Triple::mips: 1734 case Triple::mipsel: 1735 case Triple::mips64: 1736 case Triple::mips64el: 1737 if (IsMipsO32ABI || IsMipsN32ABI) 1738 Result = sizeof(uint32_t); 1739 else if (IsMipsN64ABI) 1740 Result = sizeof(uint64_t); 1741 else 1742 llvm_unreachable("Mips ABI not handled"); 1743 break; 1744 default: 1745 llvm_unreachable("Unsupported CPU type!"); 1746 } 1747 return Result; 1748 } 1749 1750 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 1751 if (GOTSectionID == 0) { 1752 GOTSectionID = Sections.size(); 1753 // Reserve a section id. We'll allocate the section later 1754 // once we know the total size 1755 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1756 } 1757 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1758 CurrentGOTIndex += no; 1759 return StartOffset; 1760 } 1761 1762 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 1763 unsigned GOTRelType) { 1764 auto E = GOTOffsetMap.insert({Value, 0}); 1765 if (E.second) { 1766 uint64_t GOTOffset = allocateGOTEntries(1); 1767 1768 // Create relocation for newly created GOT entry 1769 RelocationEntry RE = 1770 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 1771 if (Value.SymbolName) 1772 addRelocationForSymbol(RE, Value.SymbolName); 1773 else 1774 addRelocationForSection(RE, Value.SectionID); 1775 1776 E.first->second = GOTOffset; 1777 } 1778 1779 return E.first->second; 1780 } 1781 1782 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 1783 uint64_t Offset, 1784 uint64_t GOTOffset, 1785 uint32_t Type) { 1786 // Fill in the relative address of the GOT Entry into the stub 1787 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 1788 addRelocationForSection(GOTRE, GOTSectionID); 1789 } 1790 1791 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 1792 uint64_t SymbolOffset, 1793 uint32_t Type) { 1794 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1795 } 1796 1797 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1798 ObjSectionToIDMap &SectionMap) { 1799 if (IsMipsO32ABI) 1800 if (!PendingRelocs.empty()) 1801 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1802 1803 // If necessary, allocate the global offset table 1804 if (GOTSectionID != 0) { 1805 // Allocate memory for the section 1806 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1807 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1808 GOTSectionID, ".got", false); 1809 if (!Addr) 1810 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1811 1812 Sections[GOTSectionID] = 1813 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1814 1815 if (Checker) 1816 Checker->registerSection(Obj.getFileName(), GOTSectionID); 1817 1818 // For now, initialize all GOT entries to zero. We'll fill them in as 1819 // needed when GOT-based relocations are applied. 1820 memset(Addr, 0, TotalSize); 1821 if (IsMipsN32ABI || IsMipsN64ABI) { 1822 // To correctly resolve Mips GOT relocations, we need a mapping from 1823 // object's sections to GOTs. 1824 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1825 SI != SE; ++SI) { 1826 if (SI->relocation_begin() != SI->relocation_end()) { 1827 section_iterator RelocatedSection = SI->getRelocatedSection(); 1828 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1829 assert (i != SectionMap.end()); 1830 SectionToGOTMap[i->second] = GOTSectionID; 1831 } 1832 } 1833 GOTSymbolOffsets.clear(); 1834 } 1835 } 1836 1837 // Look for and record the EH frame section. 1838 ObjSectionToIDMap::iterator i, e; 1839 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1840 const SectionRef &Section = i->first; 1841 StringRef Name; 1842 Section.getName(Name); 1843 if (Name == ".eh_frame") { 1844 UnregisteredEHFrameSections.push_back(i->second); 1845 break; 1846 } 1847 } 1848 1849 GOTSectionID = 0; 1850 CurrentGOTIndex = 0; 1851 1852 return Error::success(); 1853 } 1854 1855 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1856 return Obj.isELF(); 1857 } 1858 1859 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 1860 unsigned RelTy = R.getType(); 1861 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 1862 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 1863 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 1864 1865 if (Arch == Triple::x86_64) 1866 return RelTy == ELF::R_X86_64_GOTPCREL || 1867 RelTy == ELF::R_X86_64_GOTPCRELX || 1868 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 1869 return false; 1870 } 1871 1872 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1873 if (Arch != Triple::x86_64) 1874 return true; // Conservative answer 1875 1876 switch (R.getType()) { 1877 default: 1878 return true; // Conservative answer 1879 1880 1881 case ELF::R_X86_64_GOTPCREL: 1882 case ELF::R_X86_64_GOTPCRELX: 1883 case ELF::R_X86_64_REX_GOTPCRELX: 1884 case ELF::R_X86_64_PC32: 1885 case ELF::R_X86_64_PC64: 1886 case ELF::R_X86_64_64: 1887 // We know that these reloation types won't need a stub function. This list 1888 // can be extended as needed. 1889 return false; 1890 } 1891 } 1892 1893 } // namespace llvm 1894