1 //===-- RuntimeDyldELF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Implementation of ELF support for the MC-JIT runtime dynamic linker. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "RuntimeDyldELF.h" 14 #include "RuntimeDyldCheckerImpl.h" 15 #include "Targets/RuntimeDyldELFMips.h" 16 #include "llvm/ADT/STLExtras.h" 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/ADT/Triple.h" 19 #include "llvm/BinaryFormat/ELF.h" 20 #include "llvm/Object/ELFObjectFile.h" 21 #include "llvm/Object/ObjectFile.h" 22 #include "llvm/Support/Endian.h" 23 #include "llvm/Support/MemoryBuffer.h" 24 25 using namespace llvm; 26 using namespace llvm::object; 27 using namespace llvm::support::endian; 28 29 #define DEBUG_TYPE "dyld" 30 31 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); } 32 33 static void or32AArch64Imm(void *L, uint64_t Imm) { 34 or32le(L, (Imm & 0xFFF) << 10); 35 } 36 37 template <class T> static void write(bool isBE, void *P, T V) { 38 isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V); 39 } 40 41 static void write32AArch64Addr(void *L, uint64_t Imm) { 42 uint32_t ImmLo = (Imm & 0x3) << 29; 43 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 44 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 45 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 46 } 47 48 // Return the bits [Start, End] from Val shifted Start bits. 49 // For instance, getBits(0xF0, 4, 8) returns 0xF. 50 static uint64_t getBits(uint64_t Val, int Start, int End) { 51 uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1; 52 return (Val >> Start) & Mask; 53 } 54 55 namespace { 56 57 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> { 58 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) 59 60 typedef typename ELFT::uint addr_type; 61 62 DyldELFObject(ELFObjectFile<ELFT> &&Obj); 63 64 public: 65 static Expected<std::unique_ptr<DyldELFObject>> 66 create(MemoryBufferRef Wrapper); 67 68 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 69 70 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); 71 72 // Methods for type inquiry through isa, cast and dyn_cast 73 static bool classof(const Binary *v) { 74 return (isa<ELFObjectFile<ELFT>>(v) && 75 classof(cast<ELFObjectFile<ELFT>>(v))); 76 } 77 static bool classof(const ELFObjectFile<ELFT> *v) { 78 return v->isDyldType(); 79 } 80 }; 81 82 83 84 // The MemoryBuffer passed into this constructor is just a wrapper around the 85 // actual memory. Ultimately, the Binary parent class will take ownership of 86 // this MemoryBuffer object but not the underlying memory. 87 template <class ELFT> 88 DyldELFObject<ELFT>::DyldELFObject(ELFObjectFile<ELFT> &&Obj) 89 : ELFObjectFile<ELFT>(std::move(Obj)) { 90 this->isDyldELFObject = true; 91 } 92 93 template <class ELFT> 94 Expected<std::unique_ptr<DyldELFObject<ELFT>>> 95 DyldELFObject<ELFT>::create(MemoryBufferRef Wrapper) { 96 auto Obj = ELFObjectFile<ELFT>::create(Wrapper); 97 if (auto E = Obj.takeError()) 98 return std::move(E); 99 std::unique_ptr<DyldELFObject<ELFT>> Ret( 100 new DyldELFObject<ELFT>(std::move(*Obj))); 101 return std::move(Ret); 102 } 103 104 template <class ELFT> 105 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 106 uint64_t Addr) { 107 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 108 Elf_Shdr *shdr = 109 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 110 111 // This assumes the address passed in matches the target address bitness 112 // The template-based type cast handles everything else. 113 shdr->sh_addr = static_cast<addr_type>(Addr); 114 } 115 116 template <class ELFT> 117 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 118 uint64_t Addr) { 119 120 Elf_Sym *sym = const_cast<Elf_Sym *>( 121 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 122 123 // This assumes the address passed in matches the target address bitness 124 // The template-based type cast handles everything else. 125 sym->st_value = static_cast<addr_type>(Addr); 126 } 127 128 class LoadedELFObjectInfo final 129 : public LoadedObjectInfoHelper<LoadedELFObjectInfo, 130 RuntimeDyld::LoadedObjectInfo> { 131 public: 132 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap) 133 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {} 134 135 OwningBinary<ObjectFile> 136 getObjectForDebug(const ObjectFile &Obj) const override; 137 }; 138 139 template <typename ELFT> 140 static Expected<std::unique_ptr<DyldELFObject<ELFT>>> 141 createRTDyldELFObject(MemoryBufferRef Buffer, const ObjectFile &SourceObject, 142 const LoadedELFObjectInfo &L) { 143 typedef typename ELFT::Shdr Elf_Shdr; 144 typedef typename ELFT::uint addr_type; 145 146 Expected<std::unique_ptr<DyldELFObject<ELFT>>> ObjOrErr = 147 DyldELFObject<ELFT>::create(Buffer); 148 if (Error E = ObjOrErr.takeError()) 149 return std::move(E); 150 151 std::unique_ptr<DyldELFObject<ELFT>> Obj = std::move(*ObjOrErr); 152 153 // Iterate over all sections in the object. 154 auto SI = SourceObject.section_begin(); 155 for (const auto &Sec : Obj->sections()) { 156 Expected<StringRef> NameOrErr = Sec.getName(); 157 if (!NameOrErr) { 158 consumeError(NameOrErr.takeError()); 159 continue; 160 } 161 162 if (*NameOrErr != "") { 163 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 164 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 165 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 166 167 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { 168 // This assumes that the address passed in matches the target address 169 // bitness. The template-based type cast handles everything else. 170 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 171 } 172 } 173 ++SI; 174 } 175 176 return std::move(Obj); 177 } 178 179 static OwningBinary<ObjectFile> 180 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) { 181 assert(Obj.isELF() && "Not an ELF object file."); 182 183 std::unique_ptr<MemoryBuffer> Buffer = 184 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 185 186 Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr); 187 handleAllErrors(DebugObj.takeError()); 188 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) 189 DebugObj = 190 createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L); 191 else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) 192 DebugObj = 193 createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L); 194 else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) 195 DebugObj = 196 createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L); 197 else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) 198 DebugObj = 199 createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L); 200 else 201 llvm_unreachable("Unexpected ELF format"); 202 203 handleAllErrors(DebugObj.takeError()); 204 return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer)); 205 } 206 207 OwningBinary<ObjectFile> 208 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 209 return createELFDebugObject(Obj, *this); 210 } 211 212 } // anonymous namespace 213 214 namespace llvm { 215 216 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 217 JITSymbolResolver &Resolver) 218 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 219 RuntimeDyldELF::~RuntimeDyldELF() = default; 220 221 void RuntimeDyldELF::registerEHFrames() { 222 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { 223 SID EHFrameSID = UnregisteredEHFrameSections[i]; 224 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 225 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 226 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 227 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 228 } 229 UnregisteredEHFrameSections.clear(); 230 } 231 232 std::unique_ptr<RuntimeDyldELF> 233 llvm::RuntimeDyldELF::create(Triple::ArchType Arch, 234 RuntimeDyld::MemoryManager &MemMgr, 235 JITSymbolResolver &Resolver) { 236 switch (Arch) { 237 default: 238 return std::make_unique<RuntimeDyldELF>(MemMgr, Resolver); 239 case Triple::mips: 240 case Triple::mipsel: 241 case Triple::mips64: 242 case Triple::mips64el: 243 return std::make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); 244 } 245 } 246 247 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 248 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 249 if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) 250 return std::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); 251 else { 252 HasError = true; 253 raw_string_ostream ErrStream(ErrorStr); 254 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream); 255 return nullptr; 256 } 257 } 258 259 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 260 uint64_t Offset, uint64_t Value, 261 uint32_t Type, int64_t Addend, 262 uint64_t SymOffset) { 263 switch (Type) { 264 default: 265 report_fatal_error("Relocation type not implemented yet!"); 266 break; 267 case ELF::R_X86_64_NONE: 268 break; 269 case ELF::R_X86_64_8: { 270 Value += Addend; 271 assert((int64_t)Value <= INT8_MAX && (int64_t)Value >= INT8_MIN); 272 uint8_t TruncatedAddr = (Value & 0xFF); 273 *Section.getAddressWithOffset(Offset) = TruncatedAddr; 274 LLVM_DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 275 << format("%p\n", Section.getAddressWithOffset(Offset))); 276 break; 277 } 278 case ELF::R_X86_64_16: { 279 Value += Addend; 280 assert((int64_t)Value <= INT16_MAX && (int64_t)Value >= INT16_MIN); 281 uint16_t TruncatedAddr = (Value & 0xFFFF); 282 support::ulittle16_t::ref(Section.getAddressWithOffset(Offset)) = 283 TruncatedAddr; 284 LLVM_DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 285 << format("%p\n", Section.getAddressWithOffset(Offset))); 286 break; 287 } 288 case ELF::R_X86_64_64: { 289 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 290 Value + Addend; 291 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 292 << format("%p\n", Section.getAddressWithOffset(Offset))); 293 break; 294 } 295 case ELF::R_X86_64_32: 296 case ELF::R_X86_64_32S: { 297 Value += Addend; 298 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 299 (Type == ELF::R_X86_64_32S && 300 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 301 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 302 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 303 TruncatedAddr; 304 LLVM_DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 305 << format("%p\n", Section.getAddressWithOffset(Offset))); 306 break; 307 } 308 case ELF::R_X86_64_PC8: { 309 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 310 int64_t RealOffset = Value + Addend - FinalAddress; 311 assert(isInt<8>(RealOffset)); 312 int8_t TruncOffset = (RealOffset & 0xFF); 313 Section.getAddress()[Offset] = TruncOffset; 314 break; 315 } 316 case ELF::R_X86_64_PC32: { 317 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 318 int64_t RealOffset = Value + Addend - FinalAddress; 319 assert(isInt<32>(RealOffset)); 320 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 321 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 322 TruncOffset; 323 break; 324 } 325 case ELF::R_X86_64_PC64: { 326 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 327 int64_t RealOffset = Value + Addend - FinalAddress; 328 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 329 RealOffset; 330 LLVM_DEBUG(dbgs() << "Writing " << format("%p", RealOffset) << " at " 331 << format("%p\n", FinalAddress)); 332 break; 333 } 334 case ELF::R_X86_64_GOTOFF64: { 335 // Compute Value - GOTBase. 336 uint64_t GOTBase = 0; 337 for (const auto &Section : Sections) { 338 if (Section.getName() == ".got") { 339 GOTBase = Section.getLoadAddressWithOffset(0); 340 break; 341 } 342 } 343 assert(GOTBase != 0 && "missing GOT"); 344 int64_t GOTOffset = Value - GOTBase + Addend; 345 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = GOTOffset; 346 break; 347 } 348 case ELF::R_X86_64_DTPMOD64: { 349 // We only have one DSO, so the module id is always 1. 350 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 1; 351 break; 352 } 353 case ELF::R_X86_64_DTPOFF64: 354 case ELF::R_X86_64_TPOFF64: { 355 // DTPOFF64 should resolve to the offset in the TLS block, TPOFF64 to the 356 // offset in the *initial* TLS block. Since we are statically linking, all 357 // TLS blocks already exist in the initial block, so resolve both 358 // relocations equally. 359 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 360 Value + Addend; 361 break; 362 } 363 case ELF::R_X86_64_DTPOFF32: 364 case ELF::R_X86_64_TPOFF32: { 365 // As for the (D)TPOFF64 relocations above, both DTPOFF32 and TPOFF32 can 366 // be resolved equally. 367 int64_t RealValue = Value + Addend; 368 assert(RealValue >= INT32_MIN && RealValue <= INT32_MAX); 369 int32_t TruncValue = RealValue; 370 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 371 TruncValue; 372 break; 373 } 374 } 375 } 376 377 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 378 uint64_t Offset, uint32_t Value, 379 uint32_t Type, int32_t Addend) { 380 switch (Type) { 381 case ELF::R_386_32: { 382 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 383 Value + Addend; 384 break; 385 } 386 // Handle R_386_PLT32 like R_386_PC32 since it should be able to 387 // reach any 32 bit address. 388 case ELF::R_386_PLT32: 389 case ELF::R_386_PC32: { 390 uint32_t FinalAddress = 391 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 392 uint32_t RealOffset = Value + Addend - FinalAddress; 393 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 394 RealOffset; 395 break; 396 } 397 default: 398 // There are other relocation types, but it appears these are the 399 // only ones currently used by the LLVM ELF object writer 400 report_fatal_error("Relocation type not implemented yet!"); 401 break; 402 } 403 } 404 405 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 406 uint64_t Offset, uint64_t Value, 407 uint32_t Type, int64_t Addend) { 408 uint32_t *TargetPtr = 409 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 410 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 411 // Data should use target endian. Code should always use little endian. 412 bool isBE = Arch == Triple::aarch64_be; 413 414 LLVM_DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 415 << format("%llx", Section.getAddressWithOffset(Offset)) 416 << " FinalAddress: 0x" << format("%llx", FinalAddress) 417 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 418 << format("%x", Type) << " Addend: 0x" 419 << format("%llx", Addend) << "\n"); 420 421 switch (Type) { 422 default: 423 report_fatal_error("Relocation type not implemented yet!"); 424 break; 425 case ELF::R_AARCH64_NONE: 426 break; 427 case ELF::R_AARCH64_ABS16: { 428 uint64_t Result = Value + Addend; 429 assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX); 430 write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU)); 431 break; 432 } 433 case ELF::R_AARCH64_ABS32: { 434 uint64_t Result = Value + Addend; 435 assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX); 436 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 437 break; 438 } 439 case ELF::R_AARCH64_ABS64: 440 write(isBE, TargetPtr, Value + Addend); 441 break; 442 case ELF::R_AARCH64_PLT32: { 443 uint64_t Result = Value + Addend - FinalAddress; 444 assert(static_cast<int64_t>(Result) >= INT32_MIN && 445 static_cast<int64_t>(Result) <= INT32_MAX); 446 write(isBE, TargetPtr, static_cast<uint32_t>(Result)); 447 break; 448 } 449 case ELF::R_AARCH64_PREL16: { 450 uint64_t Result = Value + Addend - FinalAddress; 451 assert(static_cast<int64_t>(Result) >= INT16_MIN && 452 static_cast<int64_t>(Result) <= UINT16_MAX); 453 write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU)); 454 break; 455 } 456 case ELF::R_AARCH64_PREL32: { 457 uint64_t Result = Value + Addend - FinalAddress; 458 assert(static_cast<int64_t>(Result) >= INT32_MIN && 459 static_cast<int64_t>(Result) <= UINT32_MAX); 460 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 461 break; 462 } 463 case ELF::R_AARCH64_PREL64: 464 write(isBE, TargetPtr, Value + Addend - FinalAddress); 465 break; 466 case ELF::R_AARCH64_CONDBR19: { 467 uint64_t BranchImm = Value + Addend - FinalAddress; 468 469 assert(isInt<21>(BranchImm)); 470 *TargetPtr &= 0xff00001fU; 471 // Immediate:20:2 goes in bits 23:5 of Bcc, CBZ, CBNZ 472 or32le(TargetPtr, (BranchImm & 0x001FFFFC) << 3); 473 break; 474 } 475 case ELF::R_AARCH64_TSTBR14: { 476 uint64_t BranchImm = Value + Addend - FinalAddress; 477 478 assert(isInt<16>(BranchImm)); 479 480 *TargetPtr &= 0xfff8001fU; 481 // Immediate:15:2 goes in bits 18:5 of TBZ, TBNZ 482 or32le(TargetPtr, (BranchImm & 0x0000FFFC) << 3); 483 break; 484 } 485 case ELF::R_AARCH64_CALL26: // fallthrough 486 case ELF::R_AARCH64_JUMP26: { 487 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 488 // calculation. 489 uint64_t BranchImm = Value + Addend - FinalAddress; 490 491 // "Check that -2^27 <= result < 2^27". 492 assert(isInt<28>(BranchImm)); 493 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 494 break; 495 } 496 case ELF::R_AARCH64_MOVW_UABS_G3: 497 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 498 break; 499 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 500 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 501 break; 502 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 503 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 504 break; 505 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 506 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 507 break; 508 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 509 // Operation: Page(S+A) - Page(P) 510 uint64_t Result = 511 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 512 513 // Check that -2^32 <= X < 2^32 514 assert(isInt<33>(Result) && "overflow check failed for relocation"); 515 516 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 517 // from bits 32:12 of X. 518 write32AArch64Addr(TargetPtr, Result >> 12); 519 break; 520 } 521 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 522 // Operation: S + A 523 // Immediate goes in bits 21:10 of LD/ST instruction, taken 524 // from bits 11:0 of X 525 or32AArch64Imm(TargetPtr, Value + Addend); 526 break; 527 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 528 // Operation: S + A 529 // Immediate goes in bits 21:10 of LD/ST instruction, taken 530 // from bits 11:0 of X 531 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 532 break; 533 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 534 // Operation: S + A 535 // Immediate goes in bits 21:10 of LD/ST instruction, taken 536 // from bits 11:1 of X 537 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 538 break; 539 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 540 // Operation: S + A 541 // Immediate goes in bits 21:10 of LD/ST instruction, taken 542 // from bits 11:2 of X 543 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 544 break; 545 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 546 // Operation: S + A 547 // Immediate goes in bits 21:10 of LD/ST instruction, taken 548 // from bits 11:3 of X 549 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 550 break; 551 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 552 // Operation: S + A 553 // Immediate goes in bits 21:10 of LD/ST instruction, taken 554 // from bits 11:4 of X 555 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 556 break; 557 case ELF::R_AARCH64_LD_PREL_LO19: { 558 // Operation: S + A - P 559 uint64_t Result = Value + Addend - FinalAddress; 560 561 // "Check that -2^20 <= result < 2^20". 562 assert(isInt<21>(Result)); 563 564 *TargetPtr &= 0xff00001fU; 565 // Immediate goes in bits 23:5 of LD imm instruction, taken 566 // from bits 20:2 of X 567 *TargetPtr |= ((Result & 0xffc) << (5 - 2)); 568 break; 569 } 570 case ELF::R_AARCH64_ADR_PREL_LO21: { 571 // Operation: S + A - P 572 uint64_t Result = Value + Addend - FinalAddress; 573 574 // "Check that -2^20 <= result < 2^20". 575 assert(isInt<21>(Result)); 576 577 *TargetPtr &= 0x9f00001fU; 578 // Immediate goes in bits 23:5, 30:29 of ADR imm instruction, taken 579 // from bits 20:0 of X 580 *TargetPtr |= ((Result & 0xffc) << (5 - 2)); 581 *TargetPtr |= (Result & 0x3) << 29; 582 break; 583 } 584 } 585 } 586 587 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 588 uint64_t Offset, uint32_t Value, 589 uint32_t Type, int32_t Addend) { 590 // TODO: Add Thumb relocations. 591 uint32_t *TargetPtr = 592 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 593 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 594 Value += Addend; 595 596 LLVM_DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 597 << Section.getAddressWithOffset(Offset) 598 << " FinalAddress: " << format("%p", FinalAddress) 599 << " Value: " << format("%x", Value) 600 << " Type: " << format("%x", Type) 601 << " Addend: " << format("%x", Addend) << "\n"); 602 603 switch (Type) { 604 default: 605 llvm_unreachable("Not implemented relocation type!"); 606 607 case ELF::R_ARM_NONE: 608 break; 609 // Write a 31bit signed offset 610 case ELF::R_ARM_PREL31: 611 support::ulittle32_t::ref{TargetPtr} = 612 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 613 ((Value - FinalAddress) & ~0x80000000); 614 break; 615 case ELF::R_ARM_TARGET1: 616 case ELF::R_ARM_ABS32: 617 support::ulittle32_t::ref{TargetPtr} = Value; 618 break; 619 // Write first 16 bit of 32 bit value to the mov instruction. 620 // Last 4 bit should be shifted. 621 case ELF::R_ARM_MOVW_ABS_NC: 622 case ELF::R_ARM_MOVT_ABS: 623 if (Type == ELF::R_ARM_MOVW_ABS_NC) 624 Value = Value & 0xFFFF; 625 else if (Type == ELF::R_ARM_MOVT_ABS) 626 Value = (Value >> 16) & 0xFFFF; 627 support::ulittle32_t::ref{TargetPtr} = 628 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 629 (((Value >> 12) & 0xF) << 16); 630 break; 631 // Write 24 bit relative value to the branch instruction. 632 case ELF::R_ARM_PC24: // Fall through. 633 case ELF::R_ARM_CALL: // Fall through. 634 case ELF::R_ARM_JUMP24: 635 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 636 RelValue = (RelValue & 0x03FFFFFC) >> 2; 637 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 638 support::ulittle32_t::ref{TargetPtr} = 639 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 640 break; 641 } 642 } 643 644 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 645 if (Arch == Triple::UnknownArch || 646 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 647 IsMipsO32ABI = false; 648 IsMipsN32ABI = false; 649 IsMipsN64ABI = false; 650 return; 651 } 652 if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) { 653 unsigned AbiVariant = E->getPlatformFlags(); 654 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 655 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 656 } 657 IsMipsN64ABI = Obj.getFileFormatName().equals("elf64-mips"); 658 } 659 660 // Return the .TOC. section and offset. 661 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 662 ObjSectionToIDMap &LocalSections, 663 RelocationValueRef &Rel) { 664 // Set a default SectionID in case we do not find a TOC section below. 665 // This may happen for references to TOC base base (sym@toc, .odp 666 // relocation) without a .toc directive. In this case just use the 667 // first section (which is usually the .odp) since the code won't 668 // reference the .toc base directly. 669 Rel.SymbolName = nullptr; 670 Rel.SectionID = 0; 671 672 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 673 // order. The TOC starts where the first of these sections starts. 674 for (auto &Section : Obj.sections()) { 675 Expected<StringRef> NameOrErr = Section.getName(); 676 if (!NameOrErr) 677 return NameOrErr.takeError(); 678 StringRef SectionName = *NameOrErr; 679 680 if (SectionName == ".got" 681 || SectionName == ".toc" 682 || SectionName == ".tocbss" 683 || SectionName == ".plt") { 684 if (auto SectionIDOrErr = 685 findOrEmitSection(Obj, Section, false, LocalSections)) 686 Rel.SectionID = *SectionIDOrErr; 687 else 688 return SectionIDOrErr.takeError(); 689 break; 690 } 691 } 692 693 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 694 // thus permitting a full 64 Kbytes segment. 695 Rel.Addend = 0x8000; 696 697 return Error::success(); 698 } 699 700 // Returns the sections and offset associated with the ODP entry referenced 701 // by Symbol. 702 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 703 ObjSectionToIDMap &LocalSections, 704 RelocationValueRef &Rel) { 705 // Get the ELF symbol value (st_value) to compare with Relocation offset in 706 // .opd entries 707 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 708 si != se; ++si) { 709 710 Expected<section_iterator> RelSecOrErr = si->getRelocatedSection(); 711 if (!RelSecOrErr) 712 report_fatal_error(Twine(toString(RelSecOrErr.takeError()))); 713 714 section_iterator RelSecI = *RelSecOrErr; 715 if (RelSecI == Obj.section_end()) 716 continue; 717 718 Expected<StringRef> NameOrErr = RelSecI->getName(); 719 if (!NameOrErr) 720 return NameOrErr.takeError(); 721 StringRef RelSectionName = *NameOrErr; 722 723 if (RelSectionName != ".opd") 724 continue; 725 726 for (elf_relocation_iterator i = si->relocation_begin(), 727 e = si->relocation_end(); 728 i != e;) { 729 // The R_PPC64_ADDR64 relocation indicates the first field 730 // of a .opd entry 731 uint64_t TypeFunc = i->getType(); 732 if (TypeFunc != ELF::R_PPC64_ADDR64) { 733 ++i; 734 continue; 735 } 736 737 uint64_t TargetSymbolOffset = i->getOffset(); 738 symbol_iterator TargetSymbol = i->getSymbol(); 739 int64_t Addend; 740 if (auto AddendOrErr = i->getAddend()) 741 Addend = *AddendOrErr; 742 else 743 return AddendOrErr.takeError(); 744 745 ++i; 746 if (i == e) 747 break; 748 749 // Just check if following relocation is a R_PPC64_TOC 750 uint64_t TypeTOC = i->getType(); 751 if (TypeTOC != ELF::R_PPC64_TOC) 752 continue; 753 754 // Finally compares the Symbol value and the target symbol offset 755 // to check if this .opd entry refers to the symbol the relocation 756 // points to. 757 if (Rel.Addend != (int64_t)TargetSymbolOffset) 758 continue; 759 760 section_iterator TSI = Obj.section_end(); 761 if (auto TSIOrErr = TargetSymbol->getSection()) 762 TSI = *TSIOrErr; 763 else 764 return TSIOrErr.takeError(); 765 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 766 767 bool IsCode = TSI->isText(); 768 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 769 LocalSections)) 770 Rel.SectionID = *SectionIDOrErr; 771 else 772 return SectionIDOrErr.takeError(); 773 Rel.Addend = (intptr_t)Addend; 774 return Error::success(); 775 } 776 } 777 llvm_unreachable("Attempting to get address of ODP entry!"); 778 } 779 780 // Relocation masks following the #lo(value), #hi(value), #ha(value), 781 // #higher(value), #highera(value), #highest(value), and #highesta(value) 782 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 783 // document. 784 785 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 786 787 static inline uint16_t applyPPChi(uint64_t value) { 788 return (value >> 16) & 0xffff; 789 } 790 791 static inline uint16_t applyPPCha (uint64_t value) { 792 return ((value + 0x8000) >> 16) & 0xffff; 793 } 794 795 static inline uint16_t applyPPChigher(uint64_t value) { 796 return (value >> 32) & 0xffff; 797 } 798 799 static inline uint16_t applyPPChighera (uint64_t value) { 800 return ((value + 0x8000) >> 32) & 0xffff; 801 } 802 803 static inline uint16_t applyPPChighest(uint64_t value) { 804 return (value >> 48) & 0xffff; 805 } 806 807 static inline uint16_t applyPPChighesta (uint64_t value) { 808 return ((value + 0x8000) >> 48) & 0xffff; 809 } 810 811 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 812 uint64_t Offset, uint64_t Value, 813 uint32_t Type, int64_t Addend) { 814 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 815 switch (Type) { 816 default: 817 report_fatal_error("Relocation type not implemented yet!"); 818 break; 819 case ELF::R_PPC_ADDR16_LO: 820 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 821 break; 822 case ELF::R_PPC_ADDR16_HI: 823 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 824 break; 825 case ELF::R_PPC_ADDR16_HA: 826 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 827 break; 828 } 829 } 830 831 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 832 uint64_t Offset, uint64_t Value, 833 uint32_t Type, int64_t Addend) { 834 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 835 switch (Type) { 836 default: 837 report_fatal_error("Relocation type not implemented yet!"); 838 break; 839 case ELF::R_PPC64_ADDR16: 840 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 841 break; 842 case ELF::R_PPC64_ADDR16_DS: 843 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 844 break; 845 case ELF::R_PPC64_ADDR16_LO: 846 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 847 break; 848 case ELF::R_PPC64_ADDR16_LO_DS: 849 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 850 break; 851 case ELF::R_PPC64_ADDR16_HI: 852 case ELF::R_PPC64_ADDR16_HIGH: 853 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 854 break; 855 case ELF::R_PPC64_ADDR16_HA: 856 case ELF::R_PPC64_ADDR16_HIGHA: 857 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 858 break; 859 case ELF::R_PPC64_ADDR16_HIGHER: 860 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 861 break; 862 case ELF::R_PPC64_ADDR16_HIGHERA: 863 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 864 break; 865 case ELF::R_PPC64_ADDR16_HIGHEST: 866 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 867 break; 868 case ELF::R_PPC64_ADDR16_HIGHESTA: 869 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 870 break; 871 case ELF::R_PPC64_ADDR14: { 872 assert(((Value + Addend) & 3) == 0); 873 // Preserve the AA/LK bits in the branch instruction 874 uint8_t aalk = *(LocalAddress + 3); 875 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 876 } break; 877 case ELF::R_PPC64_REL16_LO: { 878 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 879 uint64_t Delta = Value - FinalAddress + Addend; 880 writeInt16BE(LocalAddress, applyPPClo(Delta)); 881 } break; 882 case ELF::R_PPC64_REL16_HI: { 883 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 884 uint64_t Delta = Value - FinalAddress + Addend; 885 writeInt16BE(LocalAddress, applyPPChi(Delta)); 886 } break; 887 case ELF::R_PPC64_REL16_HA: { 888 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 889 uint64_t Delta = Value - FinalAddress + Addend; 890 writeInt16BE(LocalAddress, applyPPCha(Delta)); 891 } break; 892 case ELF::R_PPC64_ADDR32: { 893 int64_t Result = static_cast<int64_t>(Value + Addend); 894 if (SignExtend64<32>(Result) != Result) 895 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 896 writeInt32BE(LocalAddress, Result); 897 } break; 898 case ELF::R_PPC64_REL24: { 899 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 900 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 901 if (SignExtend64<26>(delta) != delta) 902 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 903 // We preserve bits other than LI field, i.e. PO and AA/LK fields. 904 uint32_t Inst = readBytesUnaligned(LocalAddress, 4); 905 writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC)); 906 } break; 907 case ELF::R_PPC64_REL32: { 908 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 909 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 910 if (SignExtend64<32>(delta) != delta) 911 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 912 writeInt32BE(LocalAddress, delta); 913 } break; 914 case ELF::R_PPC64_REL64: { 915 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 916 uint64_t Delta = Value - FinalAddress + Addend; 917 writeInt64BE(LocalAddress, Delta); 918 } break; 919 case ELF::R_PPC64_ADDR64: 920 writeInt64BE(LocalAddress, Value + Addend); 921 break; 922 } 923 } 924 925 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 926 uint64_t Offset, uint64_t Value, 927 uint32_t Type, int64_t Addend) { 928 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 929 switch (Type) { 930 default: 931 report_fatal_error("Relocation type not implemented yet!"); 932 break; 933 case ELF::R_390_PC16DBL: 934 case ELF::R_390_PLT16DBL: { 935 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 936 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 937 writeInt16BE(LocalAddress, Delta / 2); 938 break; 939 } 940 case ELF::R_390_PC32DBL: 941 case ELF::R_390_PLT32DBL: { 942 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 943 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 944 writeInt32BE(LocalAddress, Delta / 2); 945 break; 946 } 947 case ELF::R_390_PC16: { 948 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 949 assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); 950 writeInt16BE(LocalAddress, Delta); 951 break; 952 } 953 case ELF::R_390_PC32: { 954 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 955 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 956 writeInt32BE(LocalAddress, Delta); 957 break; 958 } 959 case ELF::R_390_PC64: { 960 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 961 writeInt64BE(LocalAddress, Delta); 962 break; 963 } 964 case ELF::R_390_8: 965 *LocalAddress = (uint8_t)(Value + Addend); 966 break; 967 case ELF::R_390_16: 968 writeInt16BE(LocalAddress, Value + Addend); 969 break; 970 case ELF::R_390_32: 971 writeInt32BE(LocalAddress, Value + Addend); 972 break; 973 case ELF::R_390_64: 974 writeInt64BE(LocalAddress, Value + Addend); 975 break; 976 } 977 } 978 979 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 980 uint64_t Offset, uint64_t Value, 981 uint32_t Type, int64_t Addend) { 982 bool isBE = Arch == Triple::bpfeb; 983 984 switch (Type) { 985 default: 986 report_fatal_error("Relocation type not implemented yet!"); 987 break; 988 case ELF::R_BPF_NONE: 989 case ELF::R_BPF_64_64: 990 case ELF::R_BPF_64_32: 991 case ELF::R_BPF_64_NODYLD32: 992 break; 993 case ELF::R_BPF_64_ABS64: { 994 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 995 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 996 << format("%p\n", Section.getAddressWithOffset(Offset))); 997 break; 998 } 999 case ELF::R_BPF_64_ABS32: { 1000 Value += Addend; 1001 assert(Value <= UINT32_MAX); 1002 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 1003 LLVM_DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 1004 << format("%p\n", Section.getAddressWithOffset(Offset))); 1005 break; 1006 } 1007 } 1008 } 1009 1010 // The target location for the relocation is described by RE.SectionID and 1011 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 1012 // SectionEntry has three members describing its location. 1013 // SectionEntry::Address is the address at which the section has been loaded 1014 // into memory in the current (host) process. SectionEntry::LoadAddress is the 1015 // address that the section will have in the target process. 1016 // SectionEntry::ObjAddress is the address of the bits for this section in the 1017 // original emitted object image (also in the current address space). 1018 // 1019 // Relocations will be applied as if the section were loaded at 1020 // SectionEntry::LoadAddress, but they will be applied at an address based 1021 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 1022 // Target memory contents if they are required for value calculations. 1023 // 1024 // The Value parameter here is the load address of the symbol for the 1025 // relocation to be applied. For relocations which refer to symbols in the 1026 // current object Value will be the LoadAddress of the section in which 1027 // the symbol resides (RE.Addend provides additional information about the 1028 // symbol location). For external symbols, Value will be the address of the 1029 // symbol in the target address space. 1030 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 1031 uint64_t Value) { 1032 const SectionEntry &Section = Sections[RE.SectionID]; 1033 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 1034 RE.SymOffset, RE.SectionID); 1035 } 1036 1037 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 1038 uint64_t Offset, uint64_t Value, 1039 uint32_t Type, int64_t Addend, 1040 uint64_t SymOffset, SID SectionID) { 1041 switch (Arch) { 1042 case Triple::x86_64: 1043 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 1044 break; 1045 case Triple::x86: 1046 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 1047 (uint32_t)(Addend & 0xffffffffL)); 1048 break; 1049 case Triple::aarch64: 1050 case Triple::aarch64_be: 1051 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 1052 break; 1053 case Triple::arm: // Fall through. 1054 case Triple::armeb: 1055 case Triple::thumb: 1056 case Triple::thumbeb: 1057 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 1058 (uint32_t)(Addend & 0xffffffffL)); 1059 break; 1060 case Triple::ppc: // Fall through. 1061 case Triple::ppcle: 1062 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 1063 break; 1064 case Triple::ppc64: // Fall through. 1065 case Triple::ppc64le: 1066 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 1067 break; 1068 case Triple::systemz: 1069 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 1070 break; 1071 case Triple::bpfel: 1072 case Triple::bpfeb: 1073 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 1074 break; 1075 default: 1076 llvm_unreachable("Unsupported CPU type!"); 1077 } 1078 } 1079 1080 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 1081 return (void *)(Sections[SectionID].getObjAddress() + Offset); 1082 } 1083 1084 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 1085 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 1086 if (Value.SymbolName) 1087 addRelocationForSymbol(RE, Value.SymbolName); 1088 else 1089 addRelocationForSection(RE, Value.SectionID); 1090 } 1091 1092 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 1093 bool IsLocal) const { 1094 switch (RelType) { 1095 case ELF::R_MICROMIPS_GOT16: 1096 if (IsLocal) 1097 return ELF::R_MICROMIPS_LO16; 1098 break; 1099 case ELF::R_MICROMIPS_HI16: 1100 return ELF::R_MICROMIPS_LO16; 1101 case ELF::R_MIPS_GOT16: 1102 if (IsLocal) 1103 return ELF::R_MIPS_LO16; 1104 break; 1105 case ELF::R_MIPS_HI16: 1106 return ELF::R_MIPS_LO16; 1107 case ELF::R_MIPS_PCHI16: 1108 return ELF::R_MIPS_PCLO16; 1109 default: 1110 break; 1111 } 1112 return ELF::R_MIPS_NONE; 1113 } 1114 1115 // Sometimes we don't need to create thunk for a branch. 1116 // This typically happens when branch target is located 1117 // in the same object file. In such case target is either 1118 // a weak symbol or symbol in a different executable section. 1119 // This function checks if branch target is located in the 1120 // same object file and if distance between source and target 1121 // fits R_AARCH64_CALL26 relocation. If both conditions are 1122 // met, it emits direct jump to the target and returns true. 1123 // Otherwise false is returned and thunk is created. 1124 bool RuntimeDyldELF::resolveAArch64ShortBranch( 1125 unsigned SectionID, relocation_iterator RelI, 1126 const RelocationValueRef &Value) { 1127 uint64_t Address; 1128 if (Value.SymbolName) { 1129 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 1130 1131 // Don't create direct branch for external symbols. 1132 if (Loc == GlobalSymbolTable.end()) 1133 return false; 1134 1135 const auto &SymInfo = Loc->second; 1136 Address = 1137 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 1138 SymInfo.getOffset())); 1139 } else { 1140 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 1141 } 1142 uint64_t Offset = RelI->getOffset(); 1143 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 1144 1145 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 1146 // If distance between source and target is out of range then we should 1147 // create thunk. 1148 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 1149 return false; 1150 1151 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 1152 Value.Addend); 1153 1154 return true; 1155 } 1156 1157 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 1158 const RelocationValueRef &Value, 1159 relocation_iterator RelI, 1160 StubMap &Stubs) { 1161 1162 LLVM_DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1163 SectionEntry &Section = Sections[SectionID]; 1164 1165 uint64_t Offset = RelI->getOffset(); 1166 unsigned RelType = RelI->getType(); 1167 // Look for an existing stub. 1168 StubMap::const_iterator i = Stubs.find(Value); 1169 if (i != Stubs.end()) { 1170 resolveRelocation(Section, Offset, 1171 (uint64_t)Section.getAddressWithOffset(i->second), 1172 RelType, 0); 1173 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1174 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1175 // Create a new stub function. 1176 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1177 Stubs[Value] = Section.getStubOffset(); 1178 uint8_t *StubTargetAddr = createStubFunction( 1179 Section.getAddressWithOffset(Section.getStubOffset())); 1180 1181 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1182 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1183 RelocationEntry REmovk_g2(SectionID, 1184 StubTargetAddr - Section.getAddress() + 4, 1185 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1186 RelocationEntry REmovk_g1(SectionID, 1187 StubTargetAddr - Section.getAddress() + 8, 1188 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1189 RelocationEntry REmovk_g0(SectionID, 1190 StubTargetAddr - Section.getAddress() + 12, 1191 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1192 1193 if (Value.SymbolName) { 1194 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1195 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1196 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1197 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1198 } else { 1199 addRelocationForSection(REmovz_g3, Value.SectionID); 1200 addRelocationForSection(REmovk_g2, Value.SectionID); 1201 addRelocationForSection(REmovk_g1, Value.SectionID); 1202 addRelocationForSection(REmovk_g0, Value.SectionID); 1203 } 1204 resolveRelocation(Section, Offset, 1205 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1206 Section.getStubOffset())), 1207 RelType, 0); 1208 Section.advanceStubOffset(getMaxStubSize()); 1209 } 1210 } 1211 1212 Expected<relocation_iterator> 1213 RuntimeDyldELF::processRelocationRef( 1214 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1215 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1216 const auto &Obj = cast<ELFObjectFileBase>(O); 1217 uint64_t RelType = RelI->getType(); 1218 int64_t Addend = 0; 1219 if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend()) 1220 Addend = *AddendOrErr; 1221 else 1222 consumeError(AddendOrErr.takeError()); 1223 elf_symbol_iterator Symbol = RelI->getSymbol(); 1224 1225 // Obtain the symbol name which is referenced in the relocation 1226 StringRef TargetName; 1227 if (Symbol != Obj.symbol_end()) { 1228 if (auto TargetNameOrErr = Symbol->getName()) 1229 TargetName = *TargetNameOrErr; 1230 else 1231 return TargetNameOrErr.takeError(); 1232 } 1233 LLVM_DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1234 << " TargetName: " << TargetName << "\n"); 1235 RelocationValueRef Value; 1236 // First search for the symbol in the local symbol table 1237 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1238 1239 // Search for the symbol in the global symbol table 1240 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1241 if (Symbol != Obj.symbol_end()) { 1242 gsi = GlobalSymbolTable.find(TargetName.data()); 1243 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1244 if (!SymTypeOrErr) { 1245 std::string Buf; 1246 raw_string_ostream OS(Buf); 1247 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS); 1248 report_fatal_error(Twine(OS.str())); 1249 } 1250 SymType = *SymTypeOrErr; 1251 } 1252 if (gsi != GlobalSymbolTable.end()) { 1253 const auto &SymInfo = gsi->second; 1254 Value.SectionID = SymInfo.getSectionID(); 1255 Value.Offset = SymInfo.getOffset(); 1256 Value.Addend = SymInfo.getOffset() + Addend; 1257 } else { 1258 switch (SymType) { 1259 case SymbolRef::ST_Debug: { 1260 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1261 // and can be changed by another developers. Maybe best way is add 1262 // a new symbol type ST_Section to SymbolRef and use it. 1263 auto SectionOrErr = Symbol->getSection(); 1264 if (!SectionOrErr) { 1265 std::string Buf; 1266 raw_string_ostream OS(Buf); 1267 logAllUnhandledErrors(SectionOrErr.takeError(), OS); 1268 report_fatal_error(Twine(OS.str())); 1269 } 1270 section_iterator si = *SectionOrErr; 1271 if (si == Obj.section_end()) 1272 llvm_unreachable("Symbol section not found, bad object file format!"); 1273 LLVM_DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1274 bool isCode = si->isText(); 1275 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1276 ObjSectionToID)) 1277 Value.SectionID = *SectionIDOrErr; 1278 else 1279 return SectionIDOrErr.takeError(); 1280 Value.Addend = Addend; 1281 break; 1282 } 1283 case SymbolRef::ST_Data: 1284 case SymbolRef::ST_Function: 1285 case SymbolRef::ST_Unknown: { 1286 Value.SymbolName = TargetName.data(); 1287 Value.Addend = Addend; 1288 1289 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1290 // will manifest here as a NULL symbol name. 1291 // We can set this as a valid (but empty) symbol name, and rely 1292 // on addRelocationForSymbol to handle this. 1293 if (!Value.SymbolName) 1294 Value.SymbolName = ""; 1295 break; 1296 } 1297 default: 1298 llvm_unreachable("Unresolved symbol type!"); 1299 break; 1300 } 1301 } 1302 1303 uint64_t Offset = RelI->getOffset(); 1304 1305 LLVM_DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1306 << "\n"); 1307 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1308 if ((RelType == ELF::R_AARCH64_CALL26 || 1309 RelType == ELF::R_AARCH64_JUMP26) && 1310 MemMgr.allowStubAllocation()) { 1311 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1312 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1313 // Create new GOT entry or find existing one. If GOT entry is 1314 // to be created, then we also emit ABS64 relocation for it. 1315 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1316 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1317 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1318 1319 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1320 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1321 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1322 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1323 } else { 1324 processSimpleRelocation(SectionID, Offset, RelType, Value); 1325 } 1326 } else if (Arch == Triple::arm) { 1327 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1328 RelType == ELF::R_ARM_JUMP24) { 1329 // This is an ARM branch relocation, need to use a stub function. 1330 LLVM_DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1331 SectionEntry &Section = Sections[SectionID]; 1332 1333 // Look for an existing stub. 1334 StubMap::const_iterator i = Stubs.find(Value); 1335 if (i != Stubs.end()) { 1336 resolveRelocation( 1337 Section, Offset, 1338 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1339 RelType, 0); 1340 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1341 } else { 1342 // Create a new stub function. 1343 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1344 Stubs[Value] = Section.getStubOffset(); 1345 uint8_t *StubTargetAddr = createStubFunction( 1346 Section.getAddressWithOffset(Section.getStubOffset())); 1347 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1348 ELF::R_ARM_ABS32, Value.Addend); 1349 if (Value.SymbolName) 1350 addRelocationForSymbol(RE, Value.SymbolName); 1351 else 1352 addRelocationForSection(RE, Value.SectionID); 1353 1354 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1355 Section.getAddressWithOffset( 1356 Section.getStubOffset())), 1357 RelType, 0); 1358 Section.advanceStubOffset(getMaxStubSize()); 1359 } 1360 } else { 1361 uint32_t *Placeholder = 1362 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1363 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1364 RelType == ELF::R_ARM_ABS32) { 1365 Value.Addend += *Placeholder; 1366 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1367 // See ELF for ARM documentation 1368 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1369 } 1370 processSimpleRelocation(SectionID, Offset, RelType, Value); 1371 } 1372 } else if (IsMipsO32ABI) { 1373 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1374 computePlaceholderAddress(SectionID, Offset)); 1375 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1376 if (RelType == ELF::R_MIPS_26) { 1377 // This is an Mips branch relocation, need to use a stub function. 1378 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1379 SectionEntry &Section = Sections[SectionID]; 1380 1381 // Extract the addend from the instruction. 1382 // We shift up by two since the Value will be down shifted again 1383 // when applying the relocation. 1384 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1385 1386 Value.Addend += Addend; 1387 1388 // Look up for existing stub. 1389 StubMap::const_iterator i = Stubs.find(Value); 1390 if (i != Stubs.end()) { 1391 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1392 addRelocationForSection(RE, SectionID); 1393 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1394 } else { 1395 // Create a new stub function. 1396 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1397 Stubs[Value] = Section.getStubOffset(); 1398 1399 unsigned AbiVariant = Obj.getPlatformFlags(); 1400 1401 uint8_t *StubTargetAddr = createStubFunction( 1402 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1403 1404 // Creating Hi and Lo relocations for the filled stub instructions. 1405 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1406 ELF::R_MIPS_HI16, Value.Addend); 1407 RelocationEntry RELo(SectionID, 1408 StubTargetAddr - Section.getAddress() + 4, 1409 ELF::R_MIPS_LO16, Value.Addend); 1410 1411 if (Value.SymbolName) { 1412 addRelocationForSymbol(REHi, Value.SymbolName); 1413 addRelocationForSymbol(RELo, Value.SymbolName); 1414 } else { 1415 addRelocationForSection(REHi, Value.SectionID); 1416 addRelocationForSection(RELo, Value.SectionID); 1417 } 1418 1419 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1420 addRelocationForSection(RE, SectionID); 1421 Section.advanceStubOffset(getMaxStubSize()); 1422 } 1423 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1424 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1425 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1426 PendingRelocs.push_back(std::make_pair(Value, RE)); 1427 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1428 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1429 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1430 const RelocationValueRef &MatchingValue = I->first; 1431 RelocationEntry &Reloc = I->second; 1432 if (MatchingValue == Value && 1433 RelType == getMatchingLoRelocation(Reloc.RelType) && 1434 SectionID == Reloc.SectionID) { 1435 Reloc.Addend += Addend; 1436 if (Value.SymbolName) 1437 addRelocationForSymbol(Reloc, Value.SymbolName); 1438 else 1439 addRelocationForSection(Reloc, Value.SectionID); 1440 I = PendingRelocs.erase(I); 1441 } else 1442 ++I; 1443 } 1444 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1445 if (Value.SymbolName) 1446 addRelocationForSymbol(RE, Value.SymbolName); 1447 else 1448 addRelocationForSection(RE, Value.SectionID); 1449 } else { 1450 if (RelType == ELF::R_MIPS_32) 1451 Value.Addend += Opcode; 1452 else if (RelType == ELF::R_MIPS_PC16) 1453 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1454 else if (RelType == ELF::R_MIPS_PC19_S2) 1455 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1456 else if (RelType == ELF::R_MIPS_PC21_S2) 1457 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1458 else if (RelType == ELF::R_MIPS_PC26_S2) 1459 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1460 processSimpleRelocation(SectionID, Offset, RelType, Value); 1461 } 1462 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1463 uint32_t r_type = RelType & 0xff; 1464 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1465 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1466 || r_type == ELF::R_MIPS_GOT_DISP) { 1467 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1468 if (i != GOTSymbolOffsets.end()) 1469 RE.SymOffset = i->second; 1470 else { 1471 RE.SymOffset = allocateGOTEntries(1); 1472 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1473 } 1474 if (Value.SymbolName) 1475 addRelocationForSymbol(RE, Value.SymbolName); 1476 else 1477 addRelocationForSection(RE, Value.SectionID); 1478 } else if (RelType == ELF::R_MIPS_26) { 1479 // This is an Mips branch relocation, need to use a stub function. 1480 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1481 SectionEntry &Section = Sections[SectionID]; 1482 1483 // Look up for existing stub. 1484 StubMap::const_iterator i = Stubs.find(Value); 1485 if (i != Stubs.end()) { 1486 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1487 addRelocationForSection(RE, SectionID); 1488 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1489 } else { 1490 // Create a new stub function. 1491 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1492 Stubs[Value] = Section.getStubOffset(); 1493 1494 unsigned AbiVariant = Obj.getPlatformFlags(); 1495 1496 uint8_t *StubTargetAddr = createStubFunction( 1497 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1498 1499 if (IsMipsN32ABI) { 1500 // Creating Hi and Lo relocations for the filled stub instructions. 1501 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1502 ELF::R_MIPS_HI16, Value.Addend); 1503 RelocationEntry RELo(SectionID, 1504 StubTargetAddr - Section.getAddress() + 4, 1505 ELF::R_MIPS_LO16, Value.Addend); 1506 if (Value.SymbolName) { 1507 addRelocationForSymbol(REHi, Value.SymbolName); 1508 addRelocationForSymbol(RELo, Value.SymbolName); 1509 } else { 1510 addRelocationForSection(REHi, Value.SectionID); 1511 addRelocationForSection(RELo, Value.SectionID); 1512 } 1513 } else { 1514 // Creating Highest, Higher, Hi and Lo relocations for the filled stub 1515 // instructions. 1516 RelocationEntry REHighest(SectionID, 1517 StubTargetAddr - Section.getAddress(), 1518 ELF::R_MIPS_HIGHEST, Value.Addend); 1519 RelocationEntry REHigher(SectionID, 1520 StubTargetAddr - Section.getAddress() + 4, 1521 ELF::R_MIPS_HIGHER, Value.Addend); 1522 RelocationEntry REHi(SectionID, 1523 StubTargetAddr - Section.getAddress() + 12, 1524 ELF::R_MIPS_HI16, Value.Addend); 1525 RelocationEntry RELo(SectionID, 1526 StubTargetAddr - Section.getAddress() + 20, 1527 ELF::R_MIPS_LO16, Value.Addend); 1528 if (Value.SymbolName) { 1529 addRelocationForSymbol(REHighest, Value.SymbolName); 1530 addRelocationForSymbol(REHigher, Value.SymbolName); 1531 addRelocationForSymbol(REHi, Value.SymbolName); 1532 addRelocationForSymbol(RELo, Value.SymbolName); 1533 } else { 1534 addRelocationForSection(REHighest, Value.SectionID); 1535 addRelocationForSection(REHigher, Value.SectionID); 1536 addRelocationForSection(REHi, Value.SectionID); 1537 addRelocationForSection(RELo, Value.SectionID); 1538 } 1539 } 1540 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1541 addRelocationForSection(RE, SectionID); 1542 Section.advanceStubOffset(getMaxStubSize()); 1543 } 1544 } else { 1545 processSimpleRelocation(SectionID, Offset, RelType, Value); 1546 } 1547 1548 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1549 if (RelType == ELF::R_PPC64_REL24) { 1550 // Determine ABI variant in use for this object. 1551 unsigned AbiVariant = Obj.getPlatformFlags(); 1552 AbiVariant &= ELF::EF_PPC64_ABI; 1553 // A PPC branch relocation will need a stub function if the target is 1554 // an external symbol (either Value.SymbolName is set, or SymType is 1555 // Symbol::ST_Unknown) or if the target address is not within the 1556 // signed 24-bits branch address. 1557 SectionEntry &Section = Sections[SectionID]; 1558 uint8_t *Target = Section.getAddressWithOffset(Offset); 1559 bool RangeOverflow = false; 1560 bool IsExtern = Value.SymbolName || SymType == SymbolRef::ST_Unknown; 1561 if (!IsExtern) { 1562 if (AbiVariant != 2) { 1563 // In the ELFv1 ABI, a function call may point to the .opd entry, 1564 // so the final symbol value is calculated based on the relocation 1565 // values in the .opd section. 1566 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1567 return std::move(Err); 1568 } else { 1569 // In the ELFv2 ABI, a function symbol may provide a local entry 1570 // point, which must be used for direct calls. 1571 if (Value.SectionID == SectionID){ 1572 uint8_t SymOther = Symbol->getOther(); 1573 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1574 } 1575 } 1576 uint8_t *RelocTarget = 1577 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1578 int64_t delta = static_cast<int64_t>(Target - RelocTarget); 1579 // If it is within 26-bits branch range, just set the branch target 1580 if (SignExtend64<26>(delta) != delta) { 1581 RangeOverflow = true; 1582 } else if ((AbiVariant != 2) || 1583 (AbiVariant == 2 && Value.SectionID == SectionID)) { 1584 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1585 addRelocationForSection(RE, Value.SectionID); 1586 } 1587 } 1588 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID) || 1589 RangeOverflow) { 1590 // It is an external symbol (either Value.SymbolName is set, or 1591 // SymType is SymbolRef::ST_Unknown) or out of range. 1592 StubMap::const_iterator i = Stubs.find(Value); 1593 if (i != Stubs.end()) { 1594 // Symbol function stub already created, just relocate to it 1595 resolveRelocation(Section, Offset, 1596 reinterpret_cast<uint64_t>( 1597 Section.getAddressWithOffset(i->second)), 1598 RelType, 0); 1599 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1600 } else { 1601 // Create a new stub function. 1602 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1603 Stubs[Value] = Section.getStubOffset(); 1604 uint8_t *StubTargetAddr = createStubFunction( 1605 Section.getAddressWithOffset(Section.getStubOffset()), 1606 AbiVariant); 1607 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1608 ELF::R_PPC64_ADDR64, Value.Addend); 1609 1610 // Generates the 64-bits address loads as exemplified in section 1611 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1612 // apply to the low part of the instructions, so we have to update 1613 // the offset according to the target endianness. 1614 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1615 if (!IsTargetLittleEndian) 1616 StubRelocOffset += 2; 1617 1618 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1619 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1620 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1621 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1622 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1623 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1624 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1625 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1626 1627 if (Value.SymbolName) { 1628 addRelocationForSymbol(REhst, Value.SymbolName); 1629 addRelocationForSymbol(REhr, Value.SymbolName); 1630 addRelocationForSymbol(REh, Value.SymbolName); 1631 addRelocationForSymbol(REl, Value.SymbolName); 1632 } else { 1633 addRelocationForSection(REhst, Value.SectionID); 1634 addRelocationForSection(REhr, Value.SectionID); 1635 addRelocationForSection(REh, Value.SectionID); 1636 addRelocationForSection(REl, Value.SectionID); 1637 } 1638 1639 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1640 Section.getAddressWithOffset( 1641 Section.getStubOffset())), 1642 RelType, 0); 1643 Section.advanceStubOffset(getMaxStubSize()); 1644 } 1645 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID)) { 1646 // Restore the TOC for external calls 1647 if (AbiVariant == 2) 1648 writeInt32BE(Target + 4, 0xE8410018); // ld r2,24(r1) 1649 else 1650 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1651 } 1652 } 1653 } else if (RelType == ELF::R_PPC64_TOC16 || 1654 RelType == ELF::R_PPC64_TOC16_DS || 1655 RelType == ELF::R_PPC64_TOC16_LO || 1656 RelType == ELF::R_PPC64_TOC16_LO_DS || 1657 RelType == ELF::R_PPC64_TOC16_HI || 1658 RelType == ELF::R_PPC64_TOC16_HA) { 1659 // These relocations are supposed to subtract the TOC address from 1660 // the final value. This does not fit cleanly into the RuntimeDyld 1661 // scheme, since there may be *two* sections involved in determining 1662 // the relocation value (the section of the symbol referred to by the 1663 // relocation, and the TOC section associated with the current module). 1664 // 1665 // Fortunately, these relocations are currently only ever generated 1666 // referring to symbols that themselves reside in the TOC, which means 1667 // that the two sections are actually the same. Thus they cancel out 1668 // and we can immediately resolve the relocation right now. 1669 switch (RelType) { 1670 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1671 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1672 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1673 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1674 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1675 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1676 default: llvm_unreachable("Wrong relocation type."); 1677 } 1678 1679 RelocationValueRef TOCValue; 1680 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1681 return std::move(Err); 1682 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1683 llvm_unreachable("Unsupported TOC relocation."); 1684 Value.Addend -= TOCValue.Addend; 1685 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1686 } else { 1687 // There are two ways to refer to the TOC address directly: either 1688 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1689 // ignored), or via any relocation that refers to the magic ".TOC." 1690 // symbols (in which case the addend is respected). 1691 if (RelType == ELF::R_PPC64_TOC) { 1692 RelType = ELF::R_PPC64_ADDR64; 1693 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1694 return std::move(Err); 1695 } else if (TargetName == ".TOC.") { 1696 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1697 return std::move(Err); 1698 Value.Addend += Addend; 1699 } 1700 1701 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1702 1703 if (Value.SymbolName) 1704 addRelocationForSymbol(RE, Value.SymbolName); 1705 else 1706 addRelocationForSection(RE, Value.SectionID); 1707 } 1708 } else if (Arch == Triple::systemz && 1709 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1710 // Create function stubs for both PLT and GOT references, regardless of 1711 // whether the GOT reference is to data or code. The stub contains the 1712 // full address of the symbol, as needed by GOT references, and the 1713 // executable part only adds an overhead of 8 bytes. 1714 // 1715 // We could try to conserve space by allocating the code and data 1716 // parts of the stub separately. However, as things stand, we allocate 1717 // a stub for every relocation, so using a GOT in JIT code should be 1718 // no less space efficient than using an explicit constant pool. 1719 LLVM_DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1720 SectionEntry &Section = Sections[SectionID]; 1721 1722 // Look for an existing stub. 1723 StubMap::const_iterator i = Stubs.find(Value); 1724 uintptr_t StubAddress; 1725 if (i != Stubs.end()) { 1726 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1727 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1728 } else { 1729 // Create a new stub function. 1730 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1731 1732 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1733 StubAddress = 1734 alignTo(BaseAddress + Section.getStubOffset(), getStubAlignment()); 1735 unsigned StubOffset = StubAddress - BaseAddress; 1736 1737 Stubs[Value] = StubOffset; 1738 createStubFunction((uint8_t *)StubAddress); 1739 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1740 Value.Offset); 1741 if (Value.SymbolName) 1742 addRelocationForSymbol(RE, Value.SymbolName); 1743 else 1744 addRelocationForSection(RE, Value.SectionID); 1745 Section.advanceStubOffset(getMaxStubSize()); 1746 } 1747 1748 if (RelType == ELF::R_390_GOTENT) 1749 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1750 Addend); 1751 else 1752 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1753 } else if (Arch == Triple::x86_64) { 1754 if (RelType == ELF::R_X86_64_PLT32) { 1755 // The way the PLT relocations normally work is that the linker allocates 1756 // the 1757 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1758 // entry will then jump to an address provided by the GOT. On first call, 1759 // the 1760 // GOT address will point back into PLT code that resolves the symbol. After 1761 // the first call, the GOT entry points to the actual function. 1762 // 1763 // For local functions we're ignoring all of that here and just replacing 1764 // the PLT32 relocation type with PC32, which will translate the relocation 1765 // into a PC-relative call directly to the function. For external symbols we 1766 // can't be sure the function will be within 2^32 bytes of the call site, so 1767 // we need to create a stub, which calls into the GOT. This case is 1768 // equivalent to the usual PLT implementation except that we use the stub 1769 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1770 // rather than allocating a PLT section. 1771 if (Value.SymbolName && MemMgr.allowStubAllocation()) { 1772 // This is a call to an external function. 1773 // Look for an existing stub. 1774 SectionEntry *Section = &Sections[SectionID]; 1775 StubMap::const_iterator i = Stubs.find(Value); 1776 uintptr_t StubAddress; 1777 if (i != Stubs.end()) { 1778 StubAddress = uintptr_t(Section->getAddress()) + i->second; 1779 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1780 } else { 1781 // Create a new stub function (equivalent to a PLT entry). 1782 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1783 1784 uintptr_t BaseAddress = uintptr_t(Section->getAddress()); 1785 StubAddress = alignTo(BaseAddress + Section->getStubOffset(), 1786 getStubAlignment()); 1787 unsigned StubOffset = StubAddress - BaseAddress; 1788 Stubs[Value] = StubOffset; 1789 createStubFunction((uint8_t *)StubAddress); 1790 1791 // Bump our stub offset counter 1792 Section->advanceStubOffset(getMaxStubSize()); 1793 1794 // Allocate a GOT Entry 1795 uint64_t GOTOffset = allocateGOTEntries(1); 1796 // This potentially creates a new Section which potentially 1797 // invalidates the Section pointer, so reload it. 1798 Section = &Sections[SectionID]; 1799 1800 // The load of the GOT address has an addend of -4 1801 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1802 ELF::R_X86_64_PC32); 1803 1804 // Fill in the value of the symbol we're targeting into the GOT 1805 addRelocationForSymbol( 1806 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1807 Value.SymbolName); 1808 } 1809 1810 // Make the target call a call into the stub table. 1811 resolveRelocation(*Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1812 Addend); 1813 } else { 1814 Value.Addend += support::ulittle32_t::ref( 1815 computePlaceholderAddress(SectionID, Offset)); 1816 processSimpleRelocation(SectionID, Offset, ELF::R_X86_64_PC32, Value); 1817 } 1818 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1819 RelType == ELF::R_X86_64_GOTPCRELX || 1820 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1821 uint64_t GOTOffset = allocateGOTEntries(1); 1822 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1823 ELF::R_X86_64_PC32); 1824 1825 // Fill in the value of the symbol we're targeting into the GOT 1826 RelocationEntry RE = 1827 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1828 if (Value.SymbolName) 1829 addRelocationForSymbol(RE, Value.SymbolName); 1830 else 1831 addRelocationForSection(RE, Value.SectionID); 1832 } else if (RelType == ELF::R_X86_64_GOT64) { 1833 // Fill in a 64-bit GOT offset. 1834 uint64_t GOTOffset = allocateGOTEntries(1); 1835 resolveRelocation(Sections[SectionID], Offset, GOTOffset, 1836 ELF::R_X86_64_64, 0); 1837 1838 // Fill in the value of the symbol we're targeting into the GOT 1839 RelocationEntry RE = 1840 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1841 if (Value.SymbolName) 1842 addRelocationForSymbol(RE, Value.SymbolName); 1843 else 1844 addRelocationForSection(RE, Value.SectionID); 1845 } else if (RelType == ELF::R_X86_64_GOTPC32) { 1846 // Materialize the address of the base of the GOT relative to the PC. 1847 // This doesn't create a GOT entry, but it does mean we need a GOT 1848 // section. 1849 (void)allocateGOTEntries(0); 1850 resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC32); 1851 } else if (RelType == ELF::R_X86_64_GOTPC64) { 1852 (void)allocateGOTEntries(0); 1853 resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC64); 1854 } else if (RelType == ELF::R_X86_64_GOTOFF64) { 1855 // GOTOFF relocations ultimately require a section difference relocation. 1856 (void)allocateGOTEntries(0); 1857 processSimpleRelocation(SectionID, Offset, RelType, Value); 1858 } else if (RelType == ELF::R_X86_64_PC32) { 1859 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1860 processSimpleRelocation(SectionID, Offset, RelType, Value); 1861 } else if (RelType == ELF::R_X86_64_PC64) { 1862 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1863 processSimpleRelocation(SectionID, Offset, RelType, Value); 1864 } else if (RelType == ELF::R_X86_64_GOTTPOFF) { 1865 processX86_64GOTTPOFFRelocation(SectionID, Offset, Value, Addend); 1866 } else if (RelType == ELF::R_X86_64_TLSGD || 1867 RelType == ELF::R_X86_64_TLSLD) { 1868 // The next relocation must be the relocation for __tls_get_addr. 1869 ++RelI; 1870 auto &GetAddrRelocation = *RelI; 1871 processX86_64TLSRelocation(SectionID, Offset, RelType, Value, Addend, 1872 GetAddrRelocation); 1873 } else { 1874 processSimpleRelocation(SectionID, Offset, RelType, Value); 1875 } 1876 } else { 1877 if (Arch == Triple::x86) { 1878 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1879 } 1880 processSimpleRelocation(SectionID, Offset, RelType, Value); 1881 } 1882 return ++RelI; 1883 } 1884 1885 void RuntimeDyldELF::processX86_64GOTTPOFFRelocation(unsigned SectionID, 1886 uint64_t Offset, 1887 RelocationValueRef Value, 1888 int64_t Addend) { 1889 // Use the approach from "x86-64 Linker Optimizations" from the TLS spec 1890 // to replace the GOTTPOFF relocation with a TPOFF relocation. The spec 1891 // only mentions one optimization even though there are two different 1892 // code sequences for the Initial Exec TLS Model. We match the code to 1893 // find out which one was used. 1894 1895 // A possible TLS code sequence and its replacement 1896 struct CodeSequence { 1897 // The expected code sequence 1898 ArrayRef<uint8_t> ExpectedCodeSequence; 1899 // The negative offset of the GOTTPOFF relocation to the beginning of 1900 // the sequence 1901 uint64_t TLSSequenceOffset; 1902 // The new code sequence 1903 ArrayRef<uint8_t> NewCodeSequence; 1904 // The offset of the new TPOFF relocation 1905 uint64_t TpoffRelocationOffset; 1906 }; 1907 1908 std::array<CodeSequence, 2> CodeSequences; 1909 1910 // Initial Exec Code Model Sequence 1911 { 1912 static const std::initializer_list<uint8_t> ExpectedCodeSequenceList = { 1913 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 1914 0x00, // mov %fs:0, %rax 1915 0x48, 0x03, 0x05, 0x00, 0x00, 0x00, 0x00 // add x@gotpoff(%rip), 1916 // %rax 1917 }; 1918 CodeSequences[0].ExpectedCodeSequence = 1919 ArrayRef<uint8_t>(ExpectedCodeSequenceList); 1920 CodeSequences[0].TLSSequenceOffset = 12; 1921 1922 static const std::initializer_list<uint8_t> NewCodeSequenceList = { 1923 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0, %rax 1924 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff(%rax), %rax 1925 }; 1926 CodeSequences[0].NewCodeSequence = ArrayRef<uint8_t>(NewCodeSequenceList); 1927 CodeSequences[0].TpoffRelocationOffset = 12; 1928 } 1929 1930 // Initial Exec Code Model Sequence, II 1931 { 1932 static const std::initializer_list<uint8_t> ExpectedCodeSequenceList = { 1933 0x48, 0x8b, 0x05, 0x00, 0x00, 0x00, 0x00, // mov x@gotpoff(%rip), %rax 1934 0x64, 0x48, 0x8b, 0x00, 0x00, 0x00, 0x00 // mov %fs:(%rax), %rax 1935 }; 1936 CodeSequences[1].ExpectedCodeSequence = 1937 ArrayRef<uint8_t>(ExpectedCodeSequenceList); 1938 CodeSequences[1].TLSSequenceOffset = 3; 1939 1940 static const std::initializer_list<uint8_t> NewCodeSequenceList = { 1941 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00, // 6 byte nop 1942 0x64, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:x@tpoff, %rax 1943 }; 1944 CodeSequences[1].NewCodeSequence = ArrayRef<uint8_t>(NewCodeSequenceList); 1945 CodeSequences[1].TpoffRelocationOffset = 10; 1946 } 1947 1948 bool Resolved = false; 1949 auto &Section = Sections[SectionID]; 1950 for (const auto &C : CodeSequences) { 1951 assert(C.ExpectedCodeSequence.size() == C.NewCodeSequence.size() && 1952 "Old and new code sequences must have the same size"); 1953 1954 if (Offset < C.TLSSequenceOffset || 1955 (Offset - C.TLSSequenceOffset + C.NewCodeSequence.size()) > 1956 Section.getSize()) { 1957 // This can't be a matching sequence as it doesn't fit in the current 1958 // section 1959 continue; 1960 } 1961 1962 auto TLSSequenceStartOffset = Offset - C.TLSSequenceOffset; 1963 auto *TLSSequence = Section.getAddressWithOffset(TLSSequenceStartOffset); 1964 if (ArrayRef<uint8_t>(TLSSequence, C.ExpectedCodeSequence.size()) != 1965 C.ExpectedCodeSequence) { 1966 continue; 1967 } 1968 1969 memcpy(TLSSequence, C.NewCodeSequence.data(), C.NewCodeSequence.size()); 1970 1971 // The original GOTTPOFF relocation has an addend as it is PC relative, 1972 // so it needs to be corrected. The TPOFF32 relocation is used as an 1973 // absolute value (which is an offset from %fs:0), so remove the addend 1974 // again. 1975 RelocationEntry RE(SectionID, 1976 TLSSequenceStartOffset + C.TpoffRelocationOffset, 1977 ELF::R_X86_64_TPOFF32, Value.Addend - Addend); 1978 1979 if (Value.SymbolName) 1980 addRelocationForSymbol(RE, Value.SymbolName); 1981 else 1982 addRelocationForSection(RE, Value.SectionID); 1983 1984 Resolved = true; 1985 break; 1986 } 1987 1988 if (!Resolved) { 1989 // The GOTTPOFF relocation was not used in one of the sequences 1990 // described in the spec, so we can't optimize it to a TPOFF 1991 // relocation. 1992 uint64_t GOTOffset = allocateGOTEntries(1); 1993 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1994 ELF::R_X86_64_PC32); 1995 RelocationEntry RE = 1996 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_TPOFF64); 1997 if (Value.SymbolName) 1998 addRelocationForSymbol(RE, Value.SymbolName); 1999 else 2000 addRelocationForSection(RE, Value.SectionID); 2001 } 2002 } 2003 2004 void RuntimeDyldELF::processX86_64TLSRelocation( 2005 unsigned SectionID, uint64_t Offset, uint64_t RelType, 2006 RelocationValueRef Value, int64_t Addend, 2007 const RelocationRef &GetAddrRelocation) { 2008 // Since we are statically linking and have no additional DSOs, we can resolve 2009 // the relocation directly without using __tls_get_addr. 2010 // Use the approach from "x86-64 Linker Optimizations" from the TLS spec 2011 // to replace it with the Local Exec relocation variant. 2012 2013 // Find out whether the code was compiled with the large or small memory 2014 // model. For this we look at the next relocation which is the relocation 2015 // for the __tls_get_addr function. If it's a 32 bit relocation, it's the 2016 // small code model, with a 64 bit relocation it's the large code model. 2017 bool IsSmallCodeModel; 2018 // Is the relocation for the __tls_get_addr a PC-relative GOT relocation? 2019 bool IsGOTPCRel = false; 2020 2021 switch (GetAddrRelocation.getType()) { 2022 case ELF::R_X86_64_GOTPCREL: 2023 case ELF::R_X86_64_REX_GOTPCRELX: 2024 case ELF::R_X86_64_GOTPCRELX: 2025 IsGOTPCRel = true; 2026 [[fallthrough]]; 2027 case ELF::R_X86_64_PLT32: 2028 IsSmallCodeModel = true; 2029 break; 2030 case ELF::R_X86_64_PLTOFF64: 2031 IsSmallCodeModel = false; 2032 break; 2033 default: 2034 report_fatal_error( 2035 "invalid TLS relocations for General/Local Dynamic TLS Model: " 2036 "expected PLT or GOT relocation for __tls_get_addr function"); 2037 } 2038 2039 // The negative offset to the start of the TLS code sequence relative to 2040 // the offset of the TLSGD/TLSLD relocation 2041 uint64_t TLSSequenceOffset; 2042 // The expected start of the code sequence 2043 ArrayRef<uint8_t> ExpectedCodeSequence; 2044 // The new TLS code sequence that will replace the existing code 2045 ArrayRef<uint8_t> NewCodeSequence; 2046 2047 if (RelType == ELF::R_X86_64_TLSGD) { 2048 // The offset of the new TPOFF32 relocation (offset starting from the 2049 // beginning of the whole TLS sequence) 2050 uint64_t TpoffRelocOffset; 2051 2052 if (IsSmallCodeModel) { 2053 if (!IsGOTPCRel) { 2054 static const std::initializer_list<uint8_t> CodeSequence = { 2055 0x66, // data16 (no-op prefix) 2056 0x48, 0x8d, 0x3d, 0x00, 0x00, 2057 0x00, 0x00, // lea <disp32>(%rip), %rdi 2058 0x66, 0x66, // two data16 prefixes 2059 0x48, // rex64 (no-op prefix) 2060 0xe8, 0x00, 0x00, 0x00, 0x00 // call __tls_get_addr@plt 2061 }; 2062 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2063 TLSSequenceOffset = 4; 2064 } else { 2065 // This code sequence is not described in the TLS spec but gcc 2066 // generates it sometimes. 2067 static const std::initializer_list<uint8_t> CodeSequence = { 2068 0x66, // data16 (no-op prefix) 2069 0x48, 0x8d, 0x3d, 0x00, 0x00, 2070 0x00, 0x00, // lea <disp32>(%rip), %rdi 2071 0x66, // data16 prefix (no-op prefix) 2072 0x48, // rex64 (no-op prefix) 2073 0xff, 0x15, 0x00, 0x00, 0x00, 2074 0x00 // call *__tls_get_addr@gotpcrel(%rip) 2075 }; 2076 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2077 TLSSequenceOffset = 4; 2078 } 2079 2080 // The replacement code for the small code model. It's the same for 2081 // both sequences. 2082 static const std::initializer_list<uint8_t> SmallSequence = { 2083 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 2084 0x00, // mov %fs:0, %rax 2085 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff(%rax), 2086 // %rax 2087 }; 2088 NewCodeSequence = ArrayRef<uint8_t>(SmallSequence); 2089 TpoffRelocOffset = 12; 2090 } else { 2091 static const std::initializer_list<uint8_t> CodeSequence = { 2092 0x48, 0x8d, 0x3d, 0x00, 0x00, 0x00, 0x00, // lea <disp32>(%rip), 2093 // %rdi 2094 0x48, 0xb8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 2095 0x00, // movabs $__tls_get_addr@pltoff, %rax 2096 0x48, 0x01, 0xd8, // add %rbx, %rax 2097 0xff, 0xd0 // call *%rax 2098 }; 2099 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2100 TLSSequenceOffset = 3; 2101 2102 // The replacement code for the large code model 2103 static const std::initializer_list<uint8_t> LargeSequence = { 2104 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 2105 0x00, // mov %fs:0, %rax 2106 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00, // lea x@tpoff(%rax), 2107 // %rax 2108 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00 // nopw 0x0(%rax,%rax,1) 2109 }; 2110 NewCodeSequence = ArrayRef<uint8_t>(LargeSequence); 2111 TpoffRelocOffset = 12; 2112 } 2113 2114 // The TLSGD/TLSLD relocations are PC-relative, so they have an addend. 2115 // The new TPOFF32 relocations is used as an absolute offset from 2116 // %fs:0, so remove the TLSGD/TLSLD addend again. 2117 RelocationEntry RE(SectionID, Offset - TLSSequenceOffset + TpoffRelocOffset, 2118 ELF::R_X86_64_TPOFF32, Value.Addend - Addend); 2119 if (Value.SymbolName) 2120 addRelocationForSymbol(RE, Value.SymbolName); 2121 else 2122 addRelocationForSection(RE, Value.SectionID); 2123 } else if (RelType == ELF::R_X86_64_TLSLD) { 2124 if (IsSmallCodeModel) { 2125 if (!IsGOTPCRel) { 2126 static const std::initializer_list<uint8_t> CodeSequence = { 2127 0x48, 0x8d, 0x3d, 0x00, 0x00, 0x00, // leaq <disp32>(%rip), %rdi 2128 0x00, 0xe8, 0x00, 0x00, 0x00, 0x00 // call __tls_get_addr@plt 2129 }; 2130 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2131 TLSSequenceOffset = 3; 2132 2133 // The replacement code for the small code model 2134 static const std::initializer_list<uint8_t> SmallSequence = { 2135 0x66, 0x66, 0x66, // three data16 prefixes (no-op) 2136 0x64, 0x48, 0x8b, 0x04, 0x25, 2137 0x00, 0x00, 0x00, 0x00 // mov %fs:0, %rax 2138 }; 2139 NewCodeSequence = ArrayRef<uint8_t>(SmallSequence); 2140 } else { 2141 // This code sequence is not described in the TLS spec but gcc 2142 // generates it sometimes. 2143 static const std::initializer_list<uint8_t> CodeSequence = { 2144 0x48, 0x8d, 0x3d, 0x00, 2145 0x00, 0x00, 0x00, // leaq <disp32>(%rip), %rdi 2146 0xff, 0x15, 0x00, 0x00, 2147 0x00, 0x00 // call 2148 // *__tls_get_addr@gotpcrel(%rip) 2149 }; 2150 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2151 TLSSequenceOffset = 3; 2152 2153 // The replacement is code is just like above but it needs to be 2154 // one byte longer. 2155 static const std::initializer_list<uint8_t> SmallSequence = { 2156 0x0f, 0x1f, 0x40, 0x00, // 4 byte nop 2157 0x64, 0x48, 0x8b, 0x04, 0x25, 2158 0x00, 0x00, 0x00, 0x00 // mov %fs:0, %rax 2159 }; 2160 NewCodeSequence = ArrayRef<uint8_t>(SmallSequence); 2161 } 2162 } else { 2163 // This is the same sequence as for the TLSGD sequence with the large 2164 // memory model above 2165 static const std::initializer_list<uint8_t> CodeSequence = { 2166 0x48, 0x8d, 0x3d, 0x00, 0x00, 0x00, 0x00, // lea <disp32>(%rip), 2167 // %rdi 2168 0x48, 0xb8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 2169 0x48, // movabs $__tls_get_addr@pltoff, %rax 2170 0x01, 0xd8, // add %rbx, %rax 2171 0xff, 0xd0 // call *%rax 2172 }; 2173 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2174 TLSSequenceOffset = 3; 2175 2176 // The replacement code for the large code model 2177 static const std::initializer_list<uint8_t> LargeSequence = { 2178 0x66, 0x66, 0x66, // three data16 prefixes (no-op) 2179 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 2180 0x00, // 10 byte nop 2181 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00 // mov %fs:0,%rax 2182 }; 2183 NewCodeSequence = ArrayRef<uint8_t>(LargeSequence); 2184 } 2185 } else { 2186 llvm_unreachable("both TLS relocations handled above"); 2187 } 2188 2189 assert(ExpectedCodeSequence.size() == NewCodeSequence.size() && 2190 "Old and new code sequences must have the same size"); 2191 2192 auto &Section = Sections[SectionID]; 2193 if (Offset < TLSSequenceOffset || 2194 (Offset - TLSSequenceOffset + NewCodeSequence.size()) > 2195 Section.getSize()) { 2196 report_fatal_error("unexpected end of section in TLS sequence"); 2197 } 2198 2199 auto *TLSSequence = Section.getAddressWithOffset(Offset - TLSSequenceOffset); 2200 if (ArrayRef<uint8_t>(TLSSequence, ExpectedCodeSequence.size()) != 2201 ExpectedCodeSequence) { 2202 report_fatal_error( 2203 "invalid TLS sequence for Global/Local Dynamic TLS Model"); 2204 } 2205 2206 memcpy(TLSSequence, NewCodeSequence.data(), NewCodeSequence.size()); 2207 } 2208 2209 size_t RuntimeDyldELF::getGOTEntrySize() { 2210 // We don't use the GOT in all of these cases, but it's essentially free 2211 // to put them all here. 2212 size_t Result = 0; 2213 switch (Arch) { 2214 case Triple::x86_64: 2215 case Triple::aarch64: 2216 case Triple::aarch64_be: 2217 case Triple::ppc64: 2218 case Triple::ppc64le: 2219 case Triple::systemz: 2220 Result = sizeof(uint64_t); 2221 break; 2222 case Triple::x86: 2223 case Triple::arm: 2224 case Triple::thumb: 2225 Result = sizeof(uint32_t); 2226 break; 2227 case Triple::mips: 2228 case Triple::mipsel: 2229 case Triple::mips64: 2230 case Triple::mips64el: 2231 if (IsMipsO32ABI || IsMipsN32ABI) 2232 Result = sizeof(uint32_t); 2233 else if (IsMipsN64ABI) 2234 Result = sizeof(uint64_t); 2235 else 2236 llvm_unreachable("Mips ABI not handled"); 2237 break; 2238 default: 2239 llvm_unreachable("Unsupported CPU type!"); 2240 } 2241 return Result; 2242 } 2243 2244 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 2245 if (GOTSectionID == 0) { 2246 GOTSectionID = Sections.size(); 2247 // Reserve a section id. We'll allocate the section later 2248 // once we know the total size 2249 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 2250 } 2251 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 2252 CurrentGOTIndex += no; 2253 return StartOffset; 2254 } 2255 2256 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 2257 unsigned GOTRelType) { 2258 auto E = GOTOffsetMap.insert({Value, 0}); 2259 if (E.second) { 2260 uint64_t GOTOffset = allocateGOTEntries(1); 2261 2262 // Create relocation for newly created GOT entry 2263 RelocationEntry RE = 2264 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 2265 if (Value.SymbolName) 2266 addRelocationForSymbol(RE, Value.SymbolName); 2267 else 2268 addRelocationForSection(RE, Value.SectionID); 2269 2270 E.first->second = GOTOffset; 2271 } 2272 2273 return E.first->second; 2274 } 2275 2276 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 2277 uint64_t Offset, 2278 uint64_t GOTOffset, 2279 uint32_t Type) { 2280 // Fill in the relative address of the GOT Entry into the stub 2281 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 2282 addRelocationForSection(GOTRE, GOTSectionID); 2283 } 2284 2285 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 2286 uint64_t SymbolOffset, 2287 uint32_t Type) { 2288 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 2289 } 2290 2291 void RuntimeDyldELF::processNewSymbol(const SymbolRef &ObjSymbol, SymbolTableEntry& Symbol) { 2292 // This should never return an error as `processNewSymbol` wouldn't have been 2293 // called if getFlags() returned an error before. 2294 auto ObjSymbolFlags = cantFail(ObjSymbol.getFlags()); 2295 2296 if (ObjSymbolFlags & SymbolRef::SF_Indirect) { 2297 if (IFuncStubSectionID == 0) { 2298 // Create a dummy section for the ifunc stubs. It will be actually 2299 // allocated in finalizeLoad() below. 2300 IFuncStubSectionID = Sections.size(); 2301 Sections.push_back( 2302 SectionEntry(".text.__llvm_IFuncStubs", nullptr, 0, 0, 0)); 2303 // First 64B are reserverd for the IFunc resolver 2304 IFuncStubOffset = 64; 2305 } 2306 2307 IFuncStubs.push_back(IFuncStub{IFuncStubOffset, Symbol}); 2308 // Modify the symbol so that it points to the ifunc stub instead of to the 2309 // resolver function. 2310 Symbol = SymbolTableEntry(IFuncStubSectionID, IFuncStubOffset, 2311 Symbol.getFlags()); 2312 IFuncStubOffset += getMaxIFuncStubSize(); 2313 } 2314 } 2315 2316 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 2317 ObjSectionToIDMap &SectionMap) { 2318 if (IsMipsO32ABI) 2319 if (!PendingRelocs.empty()) 2320 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 2321 2322 // Create the IFunc stubs if necessary. This must be done before processing 2323 // the GOT entries, as the IFunc stubs may create some. 2324 if (IFuncStubSectionID != 0) { 2325 uint8_t *IFuncStubsAddr = MemMgr.allocateCodeSection( 2326 IFuncStubOffset, 1, IFuncStubSectionID, ".text.__llvm_IFuncStubs"); 2327 if (!IFuncStubsAddr) 2328 return make_error<RuntimeDyldError>( 2329 "Unable to allocate memory for IFunc stubs!"); 2330 Sections[IFuncStubSectionID] = 2331 SectionEntry(".text.__llvm_IFuncStubs", IFuncStubsAddr, IFuncStubOffset, 2332 IFuncStubOffset, 0); 2333 2334 createIFuncResolver(IFuncStubsAddr); 2335 2336 LLVM_DEBUG(dbgs() << "Creating IFunc stubs SectionID: " 2337 << IFuncStubSectionID << " Addr: " 2338 << Sections[IFuncStubSectionID].getAddress() << '\n'); 2339 for (auto &IFuncStub : IFuncStubs) { 2340 auto &Symbol = IFuncStub.OriginalSymbol; 2341 LLVM_DEBUG(dbgs() << "\tSectionID: " << Symbol.getSectionID() 2342 << " Offset: " << format("%p", Symbol.getOffset()) 2343 << " IFuncStubOffset: " 2344 << format("%p\n", IFuncStub.StubOffset)); 2345 createIFuncStub(IFuncStubSectionID, 0, IFuncStub.StubOffset, 2346 Symbol.getSectionID(), Symbol.getOffset()); 2347 } 2348 2349 IFuncStubSectionID = 0; 2350 IFuncStubOffset = 0; 2351 IFuncStubs.clear(); 2352 } 2353 2354 // If necessary, allocate the global offset table 2355 if (GOTSectionID != 0) { 2356 // Allocate memory for the section 2357 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 2358 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 2359 GOTSectionID, ".got", false); 2360 if (!Addr) 2361 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 2362 2363 Sections[GOTSectionID] = 2364 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 2365 2366 // For now, initialize all GOT entries to zero. We'll fill them in as 2367 // needed when GOT-based relocations are applied. 2368 memset(Addr, 0, TotalSize); 2369 if (IsMipsN32ABI || IsMipsN64ABI) { 2370 // To correctly resolve Mips GOT relocations, we need a mapping from 2371 // object's sections to GOTs. 2372 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 2373 SI != SE; ++SI) { 2374 if (SI->relocation_begin() != SI->relocation_end()) { 2375 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection(); 2376 if (!RelSecOrErr) 2377 return make_error<RuntimeDyldError>( 2378 toString(RelSecOrErr.takeError())); 2379 2380 section_iterator RelocatedSection = *RelSecOrErr; 2381 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 2382 assert(i != SectionMap.end()); 2383 SectionToGOTMap[i->second] = GOTSectionID; 2384 } 2385 } 2386 GOTSymbolOffsets.clear(); 2387 } 2388 } 2389 2390 // Look for and record the EH frame section. 2391 ObjSectionToIDMap::iterator i, e; 2392 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 2393 const SectionRef &Section = i->first; 2394 2395 StringRef Name; 2396 Expected<StringRef> NameOrErr = Section.getName(); 2397 if (NameOrErr) 2398 Name = *NameOrErr; 2399 else 2400 consumeError(NameOrErr.takeError()); 2401 2402 if (Name == ".eh_frame") { 2403 UnregisteredEHFrameSections.push_back(i->second); 2404 break; 2405 } 2406 } 2407 2408 GOTSectionID = 0; 2409 CurrentGOTIndex = 0; 2410 2411 return Error::success(); 2412 } 2413 2414 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 2415 return Obj.isELF(); 2416 } 2417 2418 void RuntimeDyldELF::createIFuncResolver(uint8_t *Addr) const { 2419 if (Arch == Triple::x86_64) { 2420 // The adddres of the GOT1 entry is in %r11, the GOT2 entry is in %r11+8 2421 // (see createIFuncStub() for details) 2422 // The following code first saves all registers that contain the original 2423 // function arguments as those registers are not saved by the resolver 2424 // function. %r11 is saved as well so that the GOT2 entry can be updated 2425 // afterwards. Then it calls the actual IFunc resolver function whose 2426 // address is stored in GOT2. After the resolver function returns, all 2427 // saved registers are restored and the return value is written to GOT1. 2428 // Finally, jump to the now resolved function. 2429 // clang-format off 2430 const uint8_t StubCode[] = { 2431 0x57, // push %rdi 2432 0x56, // push %rsi 2433 0x52, // push %rdx 2434 0x51, // push %rcx 2435 0x41, 0x50, // push %r8 2436 0x41, 0x51, // push %r9 2437 0x41, 0x53, // push %r11 2438 0x41, 0xff, 0x53, 0x08, // call *0x8(%r11) 2439 0x41, 0x5b, // pop %r11 2440 0x41, 0x59, // pop %r9 2441 0x41, 0x58, // pop %r8 2442 0x59, // pop %rcx 2443 0x5a, // pop %rdx 2444 0x5e, // pop %rsi 2445 0x5f, // pop %rdi 2446 0x49, 0x89, 0x03, // mov %rax,(%r11) 2447 0xff, 0xe0 // jmp *%rax 2448 }; 2449 // clang-format on 2450 static_assert(sizeof(StubCode) <= 64, 2451 "maximum size of the IFunc resolver is 64B"); 2452 memcpy(Addr, StubCode, sizeof(StubCode)); 2453 } else { 2454 report_fatal_error( 2455 "IFunc resolver is not supported for target architecture"); 2456 } 2457 } 2458 2459 void RuntimeDyldELF::createIFuncStub(unsigned IFuncStubSectionID, 2460 uint64_t IFuncResolverOffset, 2461 uint64_t IFuncStubOffset, 2462 unsigned IFuncSectionID, 2463 uint64_t IFuncOffset) { 2464 auto &IFuncStubSection = Sections[IFuncStubSectionID]; 2465 auto *Addr = IFuncStubSection.getAddressWithOffset(IFuncStubOffset); 2466 2467 if (Arch == Triple::x86_64) { 2468 // The first instruction loads a PC-relative address into %r11 which is a 2469 // GOT entry for this stub. This initially contains the address to the 2470 // IFunc resolver. We can use %r11 here as it's caller saved but not used 2471 // to pass any arguments. In fact, x86_64 ABI even suggests using %r11 for 2472 // code in the PLT. The IFunc resolver will use %r11 to update the GOT 2473 // entry. 2474 // 2475 // The next instruction just jumps to the address contained in the GOT 2476 // entry. As mentioned above, we do this two-step jump by first setting 2477 // %r11 so that the IFunc resolver has access to it. 2478 // 2479 // The IFunc resolver of course also needs to know the actual address of 2480 // the actual IFunc resolver function. This will be stored in a GOT entry 2481 // right next to the first one for this stub. So, the IFunc resolver will 2482 // be able to call it with %r11+8. 2483 // 2484 // In total, two adjacent GOT entries (+relocation) and one additional 2485 // relocation are required: 2486 // GOT1: Address of the IFunc resolver. 2487 // GOT2: Address of the IFunc resolver function. 2488 // IFuncStubOffset+3: 32-bit PC-relative address of GOT1. 2489 uint64_t GOT1 = allocateGOTEntries(2); 2490 uint64_t GOT2 = GOT1 + getGOTEntrySize(); 2491 2492 RelocationEntry RE1(GOTSectionID, GOT1, ELF::R_X86_64_64, 2493 IFuncResolverOffset, {}); 2494 addRelocationForSection(RE1, IFuncStubSectionID); 2495 RelocationEntry RE2(GOTSectionID, GOT2, ELF::R_X86_64_64, IFuncOffset, {}); 2496 addRelocationForSection(RE2, IFuncSectionID); 2497 2498 const uint8_t StubCode[] = { 2499 0x4c, 0x8d, 0x1d, 0x00, 0x00, 0x00, 0x00, // leaq 0x0(%rip),%r11 2500 0x41, 0xff, 0x23 // jmpq *(%r11) 2501 }; 2502 assert(sizeof(StubCode) <= getMaxIFuncStubSize() && 2503 "IFunc stub size must not exceed getMaxIFuncStubSize()"); 2504 memcpy(Addr, StubCode, sizeof(StubCode)); 2505 2506 // The PC-relative value starts 4 bytes from the end of the leaq 2507 // instruction, so the addend is -4. 2508 resolveGOTOffsetRelocation(IFuncStubSectionID, IFuncStubOffset + 3, 2509 GOT1 - 4, ELF::R_X86_64_PC32); 2510 } else { 2511 report_fatal_error("IFunc stub is not supported for target architecture"); 2512 } 2513 } 2514 2515 unsigned RuntimeDyldELF::getMaxIFuncStubSize() const { 2516 if (Arch == Triple::x86_64) { 2517 return 10; 2518 } 2519 return 0; 2520 } 2521 2522 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 2523 unsigned RelTy = R.getType(); 2524 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 2525 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 2526 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 2527 2528 if (Arch == Triple::x86_64) 2529 return RelTy == ELF::R_X86_64_GOTPCREL || 2530 RelTy == ELF::R_X86_64_GOTPCRELX || 2531 RelTy == ELF::R_X86_64_GOT64 || 2532 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 2533 return false; 2534 } 2535 2536 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 2537 if (Arch != Triple::x86_64) 2538 return true; // Conservative answer 2539 2540 switch (R.getType()) { 2541 default: 2542 return true; // Conservative answer 2543 2544 2545 case ELF::R_X86_64_GOTPCREL: 2546 case ELF::R_X86_64_GOTPCRELX: 2547 case ELF::R_X86_64_REX_GOTPCRELX: 2548 case ELF::R_X86_64_GOTPC64: 2549 case ELF::R_X86_64_GOT64: 2550 case ELF::R_X86_64_GOTOFF64: 2551 case ELF::R_X86_64_PC32: 2552 case ELF::R_X86_64_PC64: 2553 case ELF::R_X86_64_64: 2554 // We know that these reloation types won't need a stub function. This list 2555 // can be extended as needed. 2556 return false; 2557 } 2558 } 2559 2560 } // namespace llvm 2561