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/BinaryFormat/ELF.h" 19 #include "llvm/Object/ELFObjectFile.h" 20 #include "llvm/Object/ObjectFile.h" 21 #include "llvm/Support/Endian.h" 22 #include "llvm/Support/MemoryBuffer.h" 23 #include "llvm/TargetParser/Triple.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, llvm::endianness::big>(P, V) 39 : write<T, llvm::endianness::little>(P, V); 40 } 41 42 static void write32AArch64Addr(void *L, uint64_t Imm) { 43 uint32_t ImmLo = (Imm & 0x3) << 29; 44 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 45 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 46 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 47 } 48 49 // Return the bits [Start, End] from Val shifted Start bits. 50 // For instance, getBits(0xF0, 4, 8) returns 0xF. 51 static uint64_t getBits(uint64_t Val, int Start, int End) { 52 uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1; 53 return (Val >> Start) & Mask; 54 } 55 56 namespace { 57 58 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> { 59 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) 60 61 typedef typename ELFT::uint addr_type; 62 63 DyldELFObject(ELFObjectFile<ELFT> &&Obj); 64 65 public: 66 static Expected<std::unique_ptr<DyldELFObject>> 67 create(MemoryBufferRef Wrapper); 68 69 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 70 71 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); 72 73 // Methods for type inquiry through isa, cast and dyn_cast 74 static bool classof(const Binary *v) { 75 return (isa<ELFObjectFile<ELFT>>(v) && 76 classof(cast<ELFObjectFile<ELFT>>(v))); 77 } 78 static bool classof(const ELFObjectFile<ELFT> *v) { 79 return v->isDyldType(); 80 } 81 }; 82 83 84 85 // The MemoryBuffer passed into this constructor is just a wrapper around the 86 // actual memory. Ultimately, the Binary parent class will take ownership of 87 // this MemoryBuffer object but not the underlying memory. 88 template <class ELFT> 89 DyldELFObject<ELFT>::DyldELFObject(ELFObjectFile<ELFT> &&Obj) 90 : ELFObjectFile<ELFT>(std::move(Obj)) { 91 this->isDyldELFObject = true; 92 } 93 94 template <class ELFT> 95 Expected<std::unique_ptr<DyldELFObject<ELFT>>> 96 DyldELFObject<ELFT>::create(MemoryBufferRef Wrapper) { 97 auto Obj = ELFObjectFile<ELFT>::create(Wrapper); 98 if (auto E = Obj.takeError()) 99 return std::move(E); 100 std::unique_ptr<DyldELFObject<ELFT>> Ret( 101 new DyldELFObject<ELFT>(std::move(*Obj))); 102 return std::move(Ret); 103 } 104 105 template <class ELFT> 106 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 107 uint64_t Addr) { 108 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 109 Elf_Shdr *shdr = 110 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 111 112 // This assumes the address passed in matches the target address bitness 113 // The template-based type cast handles everything else. 114 shdr->sh_addr = static_cast<addr_type>(Addr); 115 } 116 117 template <class ELFT> 118 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 119 uint64_t Addr) { 120 121 Elf_Sym *sym = const_cast<Elf_Sym *>( 122 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 123 124 // This assumes the address passed in matches the target address bitness 125 // The template-based type cast handles everything else. 126 sym->st_value = static_cast<addr_type>(Addr); 127 } 128 129 class LoadedELFObjectInfo final 130 : public LoadedObjectInfoHelper<LoadedELFObjectInfo, 131 RuntimeDyld::LoadedObjectInfo> { 132 public: 133 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap) 134 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {} 135 136 OwningBinary<ObjectFile> 137 getObjectForDebug(const ObjectFile &Obj) const override; 138 }; 139 140 template <typename ELFT> 141 static Expected<std::unique_ptr<DyldELFObject<ELFT>>> 142 createRTDyldELFObject(MemoryBufferRef Buffer, const ObjectFile &SourceObject, 143 const LoadedELFObjectInfo &L) { 144 typedef typename ELFT::Shdr Elf_Shdr; 145 typedef typename ELFT::uint addr_type; 146 147 Expected<std::unique_ptr<DyldELFObject<ELFT>>> ObjOrErr = 148 DyldELFObject<ELFT>::create(Buffer); 149 if (Error E = ObjOrErr.takeError()) 150 return std::move(E); 151 152 std::unique_ptr<DyldELFObject<ELFT>> Obj = std::move(*ObjOrErr); 153 154 // Iterate over all sections in the object. 155 auto SI = SourceObject.section_begin(); 156 for (const auto &Sec : Obj->sections()) { 157 Expected<StringRef> NameOrErr = Sec.getName(); 158 if (!NameOrErr) { 159 consumeError(NameOrErr.takeError()); 160 continue; 161 } 162 163 if (*NameOrErr != "") { 164 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 165 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 166 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 167 168 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { 169 // This assumes that the address passed in matches the target address 170 // bitness. The template-based type cast handles everything else. 171 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 172 } 173 } 174 ++SI; 175 } 176 177 return std::move(Obj); 178 } 179 180 static OwningBinary<ObjectFile> 181 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) { 182 assert(Obj.isELF() && "Not an ELF object file."); 183 184 std::unique_ptr<MemoryBuffer> Buffer = 185 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 186 187 Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr); 188 handleAllErrors(DebugObj.takeError()); 189 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) 190 DebugObj = 191 createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L); 192 else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) 193 DebugObj = 194 createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L); 195 else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) 196 DebugObj = 197 createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L); 198 else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) 199 DebugObj = 200 createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L); 201 else 202 llvm_unreachable("Unexpected ELF format"); 203 204 handleAllErrors(DebugObj.takeError()); 205 return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer)); 206 } 207 208 OwningBinary<ObjectFile> 209 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 210 return createELFDebugObject(Obj, *this); 211 } 212 213 } // anonymous namespace 214 215 namespace llvm { 216 217 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 218 JITSymbolResolver &Resolver) 219 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 220 RuntimeDyldELF::~RuntimeDyldELF() = default; 221 222 void RuntimeDyldELF::registerEHFrames() { 223 for (SID EHFrameSID : UnregisteredEHFrameSections) { 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(Result == static_cast<uint64_t>(llvm::SignExtend64(Result, 16)) || 430 (Result >> 16) == 0); 431 write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU)); 432 break; 433 } 434 case ELF::R_AARCH64_ABS32: { 435 uint64_t Result = Value + Addend; 436 assert(Result == static_cast<uint64_t>(llvm::SignExtend64(Result, 32)) || 437 (Result >> 32) == 0); 438 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 439 break; 440 } 441 case ELF::R_AARCH64_ABS64: 442 write(isBE, TargetPtr, Value + Addend); 443 break; 444 case ELF::R_AARCH64_PLT32: { 445 uint64_t Result = Value + Addend - FinalAddress; 446 assert(static_cast<int64_t>(Result) >= INT32_MIN && 447 static_cast<int64_t>(Result) <= INT32_MAX); 448 write(isBE, TargetPtr, static_cast<uint32_t>(Result)); 449 break; 450 } 451 case ELF::R_AARCH64_PREL16: { 452 uint64_t Result = Value + Addend - FinalAddress; 453 assert(static_cast<int64_t>(Result) >= INT16_MIN && 454 static_cast<int64_t>(Result) <= UINT16_MAX); 455 write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU)); 456 break; 457 } 458 case ELF::R_AARCH64_PREL32: { 459 uint64_t Result = Value + Addend - FinalAddress; 460 assert(static_cast<int64_t>(Result) >= INT32_MIN && 461 static_cast<int64_t>(Result) <= UINT32_MAX); 462 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 463 break; 464 } 465 case ELF::R_AARCH64_PREL64: 466 write(isBE, TargetPtr, Value + Addend - FinalAddress); 467 break; 468 case ELF::R_AARCH64_CONDBR19: { 469 uint64_t BranchImm = Value + Addend - FinalAddress; 470 471 assert(isInt<21>(BranchImm)); 472 *TargetPtr &= 0xff00001fU; 473 // Immediate:20:2 goes in bits 23:5 of Bcc, CBZ, CBNZ 474 or32le(TargetPtr, (BranchImm & 0x001FFFFC) << 3); 475 break; 476 } 477 case ELF::R_AARCH64_TSTBR14: { 478 uint64_t BranchImm = Value + Addend - FinalAddress; 479 480 assert(isInt<16>(BranchImm)); 481 482 uint32_t RawInstr = *(support::little32_t *)TargetPtr; 483 *(support::little32_t *)TargetPtr = RawInstr & 0xfff8001fU; 484 485 // Immediate:15:2 goes in bits 18:5 of TBZ, TBNZ 486 or32le(TargetPtr, (BranchImm & 0x0000FFFC) << 3); 487 break; 488 } 489 case ELF::R_AARCH64_CALL26: // fallthrough 490 case ELF::R_AARCH64_JUMP26: { 491 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 492 // calculation. 493 uint64_t BranchImm = Value + Addend - FinalAddress; 494 495 // "Check that -2^27 <= result < 2^27". 496 assert(isInt<28>(BranchImm)); 497 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 498 break; 499 } 500 case ELF::R_AARCH64_MOVW_UABS_G3: 501 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 502 break; 503 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 504 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 505 break; 506 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 507 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 508 break; 509 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 510 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 511 break; 512 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 513 // Operation: Page(S+A) - Page(P) 514 uint64_t Result = 515 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 516 517 // Check that -2^32 <= X < 2^32 518 assert(isInt<33>(Result) && "overflow check failed for relocation"); 519 520 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 521 // from bits 32:12 of X. 522 write32AArch64Addr(TargetPtr, Result >> 12); 523 break; 524 } 525 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 526 // Operation: S + A 527 // Immediate goes in bits 21:10 of LD/ST instruction, taken 528 // from bits 11:0 of X 529 or32AArch64Imm(TargetPtr, Value + Addend); 530 break; 531 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 532 // Operation: S + A 533 // Immediate goes in bits 21:10 of LD/ST instruction, taken 534 // from bits 11:0 of X 535 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 536 break; 537 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 538 // Operation: S + A 539 // Immediate goes in bits 21:10 of LD/ST instruction, taken 540 // from bits 11:1 of X 541 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 542 break; 543 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 544 // Operation: S + A 545 // Immediate goes in bits 21:10 of LD/ST instruction, taken 546 // from bits 11:2 of X 547 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 548 break; 549 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 550 // Operation: S + A 551 // Immediate goes in bits 21:10 of LD/ST instruction, taken 552 // from bits 11:3 of X 553 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 554 break; 555 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 556 // Operation: S + A 557 // Immediate goes in bits 21:10 of LD/ST instruction, taken 558 // from bits 11:4 of X 559 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 560 break; 561 case ELF::R_AARCH64_LD_PREL_LO19: { 562 // Operation: S + A - P 563 uint64_t Result = Value + Addend - FinalAddress; 564 565 // "Check that -2^20 <= result < 2^20". 566 assert(isInt<21>(Result)); 567 568 *TargetPtr &= 0xff00001fU; 569 // Immediate goes in bits 23:5 of LD imm instruction, taken 570 // from bits 20:2 of X 571 *TargetPtr |= ((Result & 0xffc) << (5 - 2)); 572 break; 573 } 574 case ELF::R_AARCH64_ADR_PREL_LO21: { 575 // Operation: S + A - P 576 uint64_t Result = Value + Addend - FinalAddress; 577 578 // "Check that -2^20 <= result < 2^20". 579 assert(isInt<21>(Result)); 580 581 *TargetPtr &= 0x9f00001fU; 582 // Immediate goes in bits 23:5, 30:29 of ADR imm instruction, taken 583 // from bits 20:0 of X 584 *TargetPtr |= ((Result & 0xffc) << (5 - 2)); 585 *TargetPtr |= (Result & 0x3) << 29; 586 break; 587 } 588 } 589 } 590 591 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 592 uint64_t Offset, uint32_t Value, 593 uint32_t Type, int32_t Addend) { 594 // TODO: Add Thumb relocations. 595 uint32_t *TargetPtr = 596 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 597 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 598 Value += Addend; 599 600 LLVM_DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 601 << Section.getAddressWithOffset(Offset) 602 << " FinalAddress: " << format("%p", FinalAddress) 603 << " Value: " << format("%x", Value) 604 << " Type: " << format("%x", Type) 605 << " Addend: " << format("%x", Addend) << "\n"); 606 607 switch (Type) { 608 default: 609 llvm_unreachable("Not implemented relocation type!"); 610 611 case ELF::R_ARM_NONE: 612 break; 613 // Write a 31bit signed offset 614 case ELF::R_ARM_PREL31: 615 support::ulittle32_t::ref{TargetPtr} = 616 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 617 ((Value - FinalAddress) & ~0x80000000); 618 break; 619 case ELF::R_ARM_TARGET1: 620 case ELF::R_ARM_ABS32: 621 support::ulittle32_t::ref{TargetPtr} = Value; 622 break; 623 // Write first 16 bit of 32 bit value to the mov instruction. 624 // Last 4 bit should be shifted. 625 case ELF::R_ARM_MOVW_ABS_NC: 626 case ELF::R_ARM_MOVT_ABS: 627 if (Type == ELF::R_ARM_MOVW_ABS_NC) 628 Value = Value & 0xFFFF; 629 else if (Type == ELF::R_ARM_MOVT_ABS) 630 Value = (Value >> 16) & 0xFFFF; 631 support::ulittle32_t::ref{TargetPtr} = 632 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 633 (((Value >> 12) & 0xF) << 16); 634 break; 635 // Write 24 bit relative value to the branch instruction. 636 case ELF::R_ARM_PC24: // Fall through. 637 case ELF::R_ARM_CALL: // Fall through. 638 case ELF::R_ARM_JUMP24: 639 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 640 RelValue = (RelValue & 0x03FFFFFC) >> 2; 641 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 642 support::ulittle32_t::ref{TargetPtr} = 643 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 644 break; 645 } 646 } 647 648 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 649 if (Arch == Triple::UnknownArch || 650 Triple::getArchTypePrefix(Arch) != "mips") { 651 IsMipsO32ABI = false; 652 IsMipsN32ABI = false; 653 IsMipsN64ABI = false; 654 return; 655 } 656 if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) { 657 unsigned AbiVariant = E->getPlatformFlags(); 658 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 659 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 660 } 661 IsMipsN64ABI = Obj.getFileFormatName() == "elf64-mips"; 662 } 663 664 // Return the .TOC. section and offset. 665 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 666 ObjSectionToIDMap &LocalSections, 667 RelocationValueRef &Rel) { 668 // Set a default SectionID in case we do not find a TOC section below. 669 // This may happen for references to TOC base base (sym@toc, .odp 670 // relocation) without a .toc directive. In this case just use the 671 // first section (which is usually the .odp) since the code won't 672 // reference the .toc base directly. 673 Rel.SymbolName = nullptr; 674 Rel.SectionID = 0; 675 676 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 677 // order. The TOC starts where the first of these sections starts. 678 for (auto &Section : Obj.sections()) { 679 Expected<StringRef> NameOrErr = Section.getName(); 680 if (!NameOrErr) 681 return NameOrErr.takeError(); 682 StringRef SectionName = *NameOrErr; 683 684 if (SectionName == ".got" 685 || SectionName == ".toc" 686 || SectionName == ".tocbss" 687 || SectionName == ".plt") { 688 if (auto SectionIDOrErr = 689 findOrEmitSection(Obj, Section, false, LocalSections)) 690 Rel.SectionID = *SectionIDOrErr; 691 else 692 return SectionIDOrErr.takeError(); 693 break; 694 } 695 } 696 697 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 698 // thus permitting a full 64 Kbytes segment. 699 Rel.Addend = 0x8000; 700 701 return Error::success(); 702 } 703 704 // Returns the sections and offset associated with the ODP entry referenced 705 // by Symbol. 706 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 707 ObjSectionToIDMap &LocalSections, 708 RelocationValueRef &Rel) { 709 // Get the ELF symbol value (st_value) to compare with Relocation offset in 710 // .opd entries 711 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 712 si != se; ++si) { 713 714 Expected<section_iterator> RelSecOrErr = si->getRelocatedSection(); 715 if (!RelSecOrErr) 716 report_fatal_error(Twine(toString(RelSecOrErr.takeError()))); 717 718 section_iterator RelSecI = *RelSecOrErr; 719 if (RelSecI == Obj.section_end()) 720 continue; 721 722 Expected<StringRef> NameOrErr = RelSecI->getName(); 723 if (!NameOrErr) 724 return NameOrErr.takeError(); 725 StringRef RelSectionName = *NameOrErr; 726 727 if (RelSectionName != ".opd") 728 continue; 729 730 for (elf_relocation_iterator i = si->relocation_begin(), 731 e = si->relocation_end(); 732 i != e;) { 733 // The R_PPC64_ADDR64 relocation indicates the first field 734 // of a .opd entry 735 uint64_t TypeFunc = i->getType(); 736 if (TypeFunc != ELF::R_PPC64_ADDR64) { 737 ++i; 738 continue; 739 } 740 741 uint64_t TargetSymbolOffset = i->getOffset(); 742 symbol_iterator TargetSymbol = i->getSymbol(); 743 int64_t Addend; 744 if (auto AddendOrErr = i->getAddend()) 745 Addend = *AddendOrErr; 746 else 747 return AddendOrErr.takeError(); 748 749 ++i; 750 if (i == e) 751 break; 752 753 // Just check if following relocation is a R_PPC64_TOC 754 uint64_t TypeTOC = i->getType(); 755 if (TypeTOC != ELF::R_PPC64_TOC) 756 continue; 757 758 // Finally compares the Symbol value and the target symbol offset 759 // to check if this .opd entry refers to the symbol the relocation 760 // points to. 761 if (Rel.Addend != (int64_t)TargetSymbolOffset) 762 continue; 763 764 section_iterator TSI = Obj.section_end(); 765 if (auto TSIOrErr = TargetSymbol->getSection()) 766 TSI = *TSIOrErr; 767 else 768 return TSIOrErr.takeError(); 769 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 770 771 bool IsCode = TSI->isText(); 772 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 773 LocalSections)) 774 Rel.SectionID = *SectionIDOrErr; 775 else 776 return SectionIDOrErr.takeError(); 777 Rel.Addend = (intptr_t)Addend; 778 return Error::success(); 779 } 780 } 781 llvm_unreachable("Attempting to get address of ODP entry!"); 782 } 783 784 // Relocation masks following the #lo(value), #hi(value), #ha(value), 785 // #higher(value), #highera(value), #highest(value), and #highesta(value) 786 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 787 // document. 788 789 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 790 791 static inline uint16_t applyPPChi(uint64_t value) { 792 return (value >> 16) & 0xffff; 793 } 794 795 static inline uint16_t applyPPCha (uint64_t value) { 796 return ((value + 0x8000) >> 16) & 0xffff; 797 } 798 799 static inline uint16_t applyPPChigher(uint64_t value) { 800 return (value >> 32) & 0xffff; 801 } 802 803 static inline uint16_t applyPPChighera (uint64_t value) { 804 return ((value + 0x8000) >> 32) & 0xffff; 805 } 806 807 static inline uint16_t applyPPChighest(uint64_t value) { 808 return (value >> 48) & 0xffff; 809 } 810 811 static inline uint16_t applyPPChighesta (uint64_t value) { 812 return ((value + 0x8000) >> 48) & 0xffff; 813 } 814 815 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 816 uint64_t Offset, uint64_t Value, 817 uint32_t Type, int64_t Addend) { 818 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 819 switch (Type) { 820 default: 821 report_fatal_error("Relocation type not implemented yet!"); 822 break; 823 case ELF::R_PPC_ADDR16_LO: 824 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 825 break; 826 case ELF::R_PPC_ADDR16_HI: 827 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 828 break; 829 case ELF::R_PPC_ADDR16_HA: 830 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 831 break; 832 } 833 } 834 835 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 836 uint64_t Offset, uint64_t Value, 837 uint32_t Type, int64_t Addend) { 838 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 839 switch (Type) { 840 default: 841 report_fatal_error("Relocation type not implemented yet!"); 842 break; 843 case ELF::R_PPC64_ADDR16: 844 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 845 break; 846 case ELF::R_PPC64_ADDR16_DS: 847 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 848 break; 849 case ELF::R_PPC64_ADDR16_LO: 850 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 851 break; 852 case ELF::R_PPC64_ADDR16_LO_DS: 853 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 854 break; 855 case ELF::R_PPC64_ADDR16_HI: 856 case ELF::R_PPC64_ADDR16_HIGH: 857 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 858 break; 859 case ELF::R_PPC64_ADDR16_HA: 860 case ELF::R_PPC64_ADDR16_HIGHA: 861 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 862 break; 863 case ELF::R_PPC64_ADDR16_HIGHER: 864 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 865 break; 866 case ELF::R_PPC64_ADDR16_HIGHERA: 867 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 868 break; 869 case ELF::R_PPC64_ADDR16_HIGHEST: 870 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 871 break; 872 case ELF::R_PPC64_ADDR16_HIGHESTA: 873 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 874 break; 875 case ELF::R_PPC64_ADDR14: { 876 assert(((Value + Addend) & 3) == 0); 877 // Preserve the AA/LK bits in the branch instruction 878 uint8_t aalk = *(LocalAddress + 3); 879 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 880 } break; 881 case ELF::R_PPC64_REL16_LO: { 882 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 883 uint64_t Delta = Value - FinalAddress + Addend; 884 writeInt16BE(LocalAddress, applyPPClo(Delta)); 885 } break; 886 case ELF::R_PPC64_REL16_HI: { 887 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 888 uint64_t Delta = Value - FinalAddress + Addend; 889 writeInt16BE(LocalAddress, applyPPChi(Delta)); 890 } break; 891 case ELF::R_PPC64_REL16_HA: { 892 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 893 uint64_t Delta = Value - FinalAddress + Addend; 894 writeInt16BE(LocalAddress, applyPPCha(Delta)); 895 } break; 896 case ELF::R_PPC64_ADDR32: { 897 int64_t Result = static_cast<int64_t>(Value + Addend); 898 if (SignExtend64<32>(Result) != Result) 899 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 900 writeInt32BE(LocalAddress, Result); 901 } break; 902 case ELF::R_PPC64_REL24: { 903 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 904 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 905 if (SignExtend64<26>(delta) != delta) 906 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 907 // We preserve bits other than LI field, i.e. PO and AA/LK fields. 908 uint32_t Inst = readBytesUnaligned(LocalAddress, 4); 909 writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC)); 910 } break; 911 case ELF::R_PPC64_REL32: { 912 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 913 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 914 if (SignExtend64<32>(delta) != delta) 915 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 916 writeInt32BE(LocalAddress, delta); 917 } break; 918 case ELF::R_PPC64_REL64: { 919 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 920 uint64_t Delta = Value - FinalAddress + Addend; 921 writeInt64BE(LocalAddress, Delta); 922 } break; 923 case ELF::R_PPC64_ADDR64: 924 writeInt64BE(LocalAddress, Value + Addend); 925 break; 926 } 927 } 928 929 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 930 uint64_t Offset, uint64_t Value, 931 uint32_t Type, int64_t Addend) { 932 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 933 switch (Type) { 934 default: 935 report_fatal_error("Relocation type not implemented yet!"); 936 break; 937 case ELF::R_390_PC16DBL: 938 case ELF::R_390_PLT16DBL: { 939 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 940 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 941 writeInt16BE(LocalAddress, Delta / 2); 942 break; 943 } 944 case ELF::R_390_PC32DBL: 945 case ELF::R_390_PLT32DBL: { 946 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 947 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 948 writeInt32BE(LocalAddress, Delta / 2); 949 break; 950 } 951 case ELF::R_390_PC16: { 952 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 953 assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); 954 writeInt16BE(LocalAddress, Delta); 955 break; 956 } 957 case ELF::R_390_PC32: { 958 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 959 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 960 writeInt32BE(LocalAddress, Delta); 961 break; 962 } 963 case ELF::R_390_PC64: { 964 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 965 writeInt64BE(LocalAddress, Delta); 966 break; 967 } 968 case ELF::R_390_8: 969 *LocalAddress = (uint8_t)(Value + Addend); 970 break; 971 case ELF::R_390_16: 972 writeInt16BE(LocalAddress, Value + Addend); 973 break; 974 case ELF::R_390_32: 975 writeInt32BE(LocalAddress, Value + Addend); 976 break; 977 case ELF::R_390_64: 978 writeInt64BE(LocalAddress, Value + Addend); 979 break; 980 } 981 } 982 983 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 984 uint64_t Offset, uint64_t Value, 985 uint32_t Type, int64_t Addend) { 986 bool isBE = Arch == Triple::bpfeb; 987 988 switch (Type) { 989 default: 990 report_fatal_error("Relocation type not implemented yet!"); 991 break; 992 case ELF::R_BPF_NONE: 993 case ELF::R_BPF_64_64: 994 case ELF::R_BPF_64_32: 995 case ELF::R_BPF_64_NODYLD32: 996 break; 997 case ELF::R_BPF_64_ABS64: { 998 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 999 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 1000 << format("%p\n", Section.getAddressWithOffset(Offset))); 1001 break; 1002 } 1003 case ELF::R_BPF_64_ABS32: { 1004 Value += Addend; 1005 assert(Value <= UINT32_MAX); 1006 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 1007 LLVM_DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 1008 << format("%p\n", Section.getAddressWithOffset(Offset))); 1009 break; 1010 } 1011 } 1012 } 1013 1014 // The target location for the relocation is described by RE.SectionID and 1015 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 1016 // SectionEntry has three members describing its location. 1017 // SectionEntry::Address is the address at which the section has been loaded 1018 // into memory in the current (host) process. SectionEntry::LoadAddress is the 1019 // address that the section will have in the target process. 1020 // SectionEntry::ObjAddress is the address of the bits for this section in the 1021 // original emitted object image (also in the current address space). 1022 // 1023 // Relocations will be applied as if the section were loaded at 1024 // SectionEntry::LoadAddress, but they will be applied at an address based 1025 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 1026 // Target memory contents if they are required for value calculations. 1027 // 1028 // The Value parameter here is the load address of the symbol for the 1029 // relocation to be applied. For relocations which refer to symbols in the 1030 // current object Value will be the LoadAddress of the section in which 1031 // the symbol resides (RE.Addend provides additional information about the 1032 // symbol location). For external symbols, Value will be the address of the 1033 // symbol in the target address space. 1034 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 1035 uint64_t Value) { 1036 const SectionEntry &Section = Sections[RE.SectionID]; 1037 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 1038 RE.SymOffset, RE.SectionID); 1039 } 1040 1041 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 1042 uint64_t Offset, uint64_t Value, 1043 uint32_t Type, int64_t Addend, 1044 uint64_t SymOffset, SID SectionID) { 1045 switch (Arch) { 1046 case Triple::x86_64: 1047 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 1048 break; 1049 case Triple::x86: 1050 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 1051 (uint32_t)(Addend & 0xffffffffL)); 1052 break; 1053 case Triple::aarch64: 1054 case Triple::aarch64_be: 1055 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 1056 break; 1057 case Triple::arm: // Fall through. 1058 case Triple::armeb: 1059 case Triple::thumb: 1060 case Triple::thumbeb: 1061 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 1062 (uint32_t)(Addend & 0xffffffffL)); 1063 break; 1064 case Triple::ppc: // Fall through. 1065 case Triple::ppcle: 1066 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 1067 break; 1068 case Triple::ppc64: // Fall through. 1069 case Triple::ppc64le: 1070 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 1071 break; 1072 case Triple::systemz: 1073 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 1074 break; 1075 case Triple::bpfel: 1076 case Triple::bpfeb: 1077 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 1078 break; 1079 default: 1080 llvm_unreachable("Unsupported CPU type!"); 1081 } 1082 } 1083 1084 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 1085 return (void *)(Sections[SectionID].getObjAddress() + Offset); 1086 } 1087 1088 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 1089 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 1090 if (Value.SymbolName) 1091 addRelocationForSymbol(RE, Value.SymbolName); 1092 else 1093 addRelocationForSection(RE, Value.SectionID); 1094 } 1095 1096 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 1097 bool IsLocal) const { 1098 switch (RelType) { 1099 case ELF::R_MICROMIPS_GOT16: 1100 if (IsLocal) 1101 return ELF::R_MICROMIPS_LO16; 1102 break; 1103 case ELF::R_MICROMIPS_HI16: 1104 return ELF::R_MICROMIPS_LO16; 1105 case ELF::R_MIPS_GOT16: 1106 if (IsLocal) 1107 return ELF::R_MIPS_LO16; 1108 break; 1109 case ELF::R_MIPS_HI16: 1110 return ELF::R_MIPS_LO16; 1111 case ELF::R_MIPS_PCHI16: 1112 return ELF::R_MIPS_PCLO16; 1113 default: 1114 break; 1115 } 1116 return ELF::R_MIPS_NONE; 1117 } 1118 1119 // Sometimes we don't need to create thunk for a branch. 1120 // This typically happens when branch target is located 1121 // in the same object file. In such case target is either 1122 // a weak symbol or symbol in a different executable section. 1123 // This function checks if branch target is located in the 1124 // same object file and if distance between source and target 1125 // fits R_AARCH64_CALL26 relocation. If both conditions are 1126 // met, it emits direct jump to the target and returns true. 1127 // Otherwise false is returned and thunk is created. 1128 bool RuntimeDyldELF::resolveAArch64ShortBranch( 1129 unsigned SectionID, relocation_iterator RelI, 1130 const RelocationValueRef &Value) { 1131 uint64_t TargetOffset; 1132 unsigned TargetSectionID; 1133 if (Value.SymbolName) { 1134 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 1135 1136 // Don't create direct branch for external symbols. 1137 if (Loc == GlobalSymbolTable.end()) 1138 return false; 1139 1140 const auto &SymInfo = Loc->second; 1141 1142 TargetSectionID = SymInfo.getSectionID(); 1143 TargetOffset = SymInfo.getOffset(); 1144 } else { 1145 TargetSectionID = Value.SectionID; 1146 TargetOffset = 0; 1147 } 1148 1149 // We don't actually know the load addresses at this point, so if the 1150 // branch is cross-section, we don't know exactly how far away it is. 1151 if (TargetSectionID != SectionID) 1152 return false; 1153 1154 uint64_t SourceOffset = RelI->getOffset(); 1155 1156 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 1157 // If distance between source and target is out of range then we should 1158 // create thunk. 1159 if (!isInt<28>(TargetOffset + Value.Addend - SourceOffset)) 1160 return false; 1161 1162 RelocationEntry RE(SectionID, SourceOffset, RelI->getType(), Value.Addend); 1163 if (Value.SymbolName) 1164 addRelocationForSymbol(RE, Value.SymbolName); 1165 else 1166 addRelocationForSection(RE, Value.SectionID); 1167 1168 return true; 1169 } 1170 1171 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 1172 const RelocationValueRef &Value, 1173 relocation_iterator RelI, 1174 StubMap &Stubs) { 1175 1176 LLVM_DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1177 SectionEntry &Section = Sections[SectionID]; 1178 1179 uint64_t Offset = RelI->getOffset(); 1180 unsigned RelType = RelI->getType(); 1181 // Look for an existing stub. 1182 StubMap::const_iterator i = Stubs.find(Value); 1183 if (i != Stubs.end()) { 1184 resolveRelocation(Section, Offset, 1185 Section.getLoadAddressWithOffset(i->second), RelType, 0); 1186 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1187 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1188 // Create a new stub function. 1189 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1190 Stubs[Value] = Section.getStubOffset(); 1191 uint8_t *StubTargetAddr = createStubFunction( 1192 Section.getAddressWithOffset(Section.getStubOffset())); 1193 1194 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1195 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1196 RelocationEntry REmovk_g2(SectionID, 1197 StubTargetAddr - Section.getAddress() + 4, 1198 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1199 RelocationEntry REmovk_g1(SectionID, 1200 StubTargetAddr - Section.getAddress() + 8, 1201 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1202 RelocationEntry REmovk_g0(SectionID, 1203 StubTargetAddr - Section.getAddress() + 12, 1204 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1205 1206 if (Value.SymbolName) { 1207 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1208 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1209 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1210 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1211 } else { 1212 addRelocationForSection(REmovz_g3, Value.SectionID); 1213 addRelocationForSection(REmovk_g2, Value.SectionID); 1214 addRelocationForSection(REmovk_g1, Value.SectionID); 1215 addRelocationForSection(REmovk_g0, Value.SectionID); 1216 } 1217 resolveRelocation(Section, Offset, 1218 Section.getLoadAddressWithOffset(Section.getStubOffset()), 1219 RelType, 0); 1220 Section.advanceStubOffset(getMaxStubSize()); 1221 } 1222 } 1223 1224 Expected<relocation_iterator> 1225 RuntimeDyldELF::processRelocationRef( 1226 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1227 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1228 const auto &Obj = cast<ELFObjectFileBase>(O); 1229 uint64_t RelType = RelI->getType(); 1230 int64_t Addend = 0; 1231 if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend()) 1232 Addend = *AddendOrErr; 1233 else 1234 consumeError(AddendOrErr.takeError()); 1235 elf_symbol_iterator Symbol = RelI->getSymbol(); 1236 1237 // Obtain the symbol name which is referenced in the relocation 1238 StringRef TargetName; 1239 if (Symbol != Obj.symbol_end()) { 1240 if (auto TargetNameOrErr = Symbol->getName()) 1241 TargetName = *TargetNameOrErr; 1242 else 1243 return TargetNameOrErr.takeError(); 1244 } 1245 LLVM_DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1246 << " TargetName: " << TargetName << "\n"); 1247 RelocationValueRef Value; 1248 // First search for the symbol in the local symbol table 1249 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1250 1251 // Search for the symbol in the global symbol table 1252 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1253 if (Symbol != Obj.symbol_end()) { 1254 gsi = GlobalSymbolTable.find(TargetName.data()); 1255 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1256 if (!SymTypeOrErr) { 1257 std::string Buf; 1258 raw_string_ostream OS(Buf); 1259 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS); 1260 report_fatal_error(Twine(OS.str())); 1261 } 1262 SymType = *SymTypeOrErr; 1263 } 1264 if (gsi != GlobalSymbolTable.end()) { 1265 const auto &SymInfo = gsi->second; 1266 Value.SectionID = SymInfo.getSectionID(); 1267 Value.Offset = SymInfo.getOffset(); 1268 Value.Addend = SymInfo.getOffset() + Addend; 1269 } else { 1270 switch (SymType) { 1271 case SymbolRef::ST_Debug: { 1272 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1273 // and can be changed by another developers. Maybe best way is add 1274 // a new symbol type ST_Section to SymbolRef and use it. 1275 auto SectionOrErr = Symbol->getSection(); 1276 if (!SectionOrErr) { 1277 std::string Buf; 1278 raw_string_ostream OS(Buf); 1279 logAllUnhandledErrors(SectionOrErr.takeError(), OS); 1280 report_fatal_error(Twine(OS.str())); 1281 } 1282 section_iterator si = *SectionOrErr; 1283 if (si == Obj.section_end()) 1284 llvm_unreachable("Symbol section not found, bad object file format!"); 1285 LLVM_DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1286 bool isCode = si->isText(); 1287 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1288 ObjSectionToID)) 1289 Value.SectionID = *SectionIDOrErr; 1290 else 1291 return SectionIDOrErr.takeError(); 1292 Value.Addend = Addend; 1293 break; 1294 } 1295 case SymbolRef::ST_Data: 1296 case SymbolRef::ST_Function: 1297 case SymbolRef::ST_Other: 1298 case SymbolRef::ST_Unknown: { 1299 Value.SymbolName = TargetName.data(); 1300 Value.Addend = Addend; 1301 1302 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1303 // will manifest here as a NULL symbol name. 1304 // We can set this as a valid (but empty) symbol name, and rely 1305 // on addRelocationForSymbol to handle this. 1306 if (!Value.SymbolName) 1307 Value.SymbolName = ""; 1308 break; 1309 } 1310 default: 1311 llvm_unreachable("Unresolved symbol type!"); 1312 break; 1313 } 1314 } 1315 1316 uint64_t Offset = RelI->getOffset(); 1317 1318 LLVM_DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1319 << "\n"); 1320 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1321 if ((RelType == ELF::R_AARCH64_CALL26 || 1322 RelType == ELF::R_AARCH64_JUMP26) && 1323 MemMgr.allowStubAllocation()) { 1324 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1325 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1326 // Create new GOT entry or find existing one. If GOT entry is 1327 // to be created, then we also emit ABS64 relocation for it. 1328 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1329 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1330 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1331 1332 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1333 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1334 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1335 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1336 } else { 1337 processSimpleRelocation(SectionID, Offset, RelType, Value); 1338 } 1339 } else if (Arch == Triple::arm) { 1340 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1341 RelType == ELF::R_ARM_JUMP24) { 1342 // This is an ARM branch relocation, need to use a stub function. 1343 LLVM_DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1344 SectionEntry &Section = Sections[SectionID]; 1345 1346 // Look for an existing stub. 1347 StubMap::const_iterator i = Stubs.find(Value); 1348 if (i != Stubs.end()) { 1349 resolveRelocation(Section, Offset, 1350 Section.getLoadAddressWithOffset(i->second), RelType, 1351 0); 1352 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1353 } else { 1354 // Create a new stub function. 1355 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1356 Stubs[Value] = Section.getStubOffset(); 1357 uint8_t *StubTargetAddr = createStubFunction( 1358 Section.getAddressWithOffset(Section.getStubOffset())); 1359 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1360 ELF::R_ARM_ABS32, Value.Addend); 1361 if (Value.SymbolName) 1362 addRelocationForSymbol(RE, Value.SymbolName); 1363 else 1364 addRelocationForSection(RE, Value.SectionID); 1365 1366 resolveRelocation( 1367 Section, Offset, 1368 Section.getLoadAddressWithOffset(Section.getStubOffset()), RelType, 1369 0); 1370 Section.advanceStubOffset(getMaxStubSize()); 1371 } 1372 } else { 1373 uint32_t *Placeholder = 1374 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1375 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1376 RelType == ELF::R_ARM_ABS32) { 1377 Value.Addend += *Placeholder; 1378 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1379 // See ELF for ARM documentation 1380 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1381 } 1382 processSimpleRelocation(SectionID, Offset, RelType, Value); 1383 } 1384 } else if (IsMipsO32ABI) { 1385 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1386 computePlaceholderAddress(SectionID, Offset)); 1387 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1388 if (RelType == ELF::R_MIPS_26) { 1389 // This is an Mips branch relocation, need to use a stub function. 1390 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1391 SectionEntry &Section = Sections[SectionID]; 1392 1393 // Extract the addend from the instruction. 1394 // We shift up by two since the Value will be down shifted again 1395 // when applying the relocation. 1396 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1397 1398 Value.Addend += Addend; 1399 1400 // Look up for existing stub. 1401 StubMap::const_iterator i = Stubs.find(Value); 1402 if (i != Stubs.end()) { 1403 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1404 addRelocationForSection(RE, SectionID); 1405 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1406 } else { 1407 // Create a new stub function. 1408 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1409 Stubs[Value] = Section.getStubOffset(); 1410 1411 unsigned AbiVariant = Obj.getPlatformFlags(); 1412 1413 uint8_t *StubTargetAddr = createStubFunction( 1414 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1415 1416 // Creating Hi and Lo relocations for the filled stub instructions. 1417 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1418 ELF::R_MIPS_HI16, Value.Addend); 1419 RelocationEntry RELo(SectionID, 1420 StubTargetAddr - Section.getAddress() + 4, 1421 ELF::R_MIPS_LO16, Value.Addend); 1422 1423 if (Value.SymbolName) { 1424 addRelocationForSymbol(REHi, Value.SymbolName); 1425 addRelocationForSymbol(RELo, Value.SymbolName); 1426 } else { 1427 addRelocationForSection(REHi, Value.SectionID); 1428 addRelocationForSection(RELo, Value.SectionID); 1429 } 1430 1431 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1432 addRelocationForSection(RE, SectionID); 1433 Section.advanceStubOffset(getMaxStubSize()); 1434 } 1435 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1436 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1437 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1438 PendingRelocs.push_back(std::make_pair(Value, RE)); 1439 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1440 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1441 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1442 const RelocationValueRef &MatchingValue = I->first; 1443 RelocationEntry &Reloc = I->second; 1444 if (MatchingValue == Value && 1445 RelType == getMatchingLoRelocation(Reloc.RelType) && 1446 SectionID == Reloc.SectionID) { 1447 Reloc.Addend += Addend; 1448 if (Value.SymbolName) 1449 addRelocationForSymbol(Reloc, Value.SymbolName); 1450 else 1451 addRelocationForSection(Reloc, Value.SectionID); 1452 I = PendingRelocs.erase(I); 1453 } else 1454 ++I; 1455 } 1456 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1457 if (Value.SymbolName) 1458 addRelocationForSymbol(RE, Value.SymbolName); 1459 else 1460 addRelocationForSection(RE, Value.SectionID); 1461 } else { 1462 if (RelType == ELF::R_MIPS_32) 1463 Value.Addend += Opcode; 1464 else if (RelType == ELF::R_MIPS_PC16) 1465 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1466 else if (RelType == ELF::R_MIPS_PC19_S2) 1467 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1468 else if (RelType == ELF::R_MIPS_PC21_S2) 1469 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1470 else if (RelType == ELF::R_MIPS_PC26_S2) 1471 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1472 processSimpleRelocation(SectionID, Offset, RelType, Value); 1473 } 1474 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1475 uint32_t r_type = RelType & 0xff; 1476 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1477 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1478 || r_type == ELF::R_MIPS_GOT_DISP) { 1479 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1480 if (i != GOTSymbolOffsets.end()) 1481 RE.SymOffset = i->second; 1482 else { 1483 RE.SymOffset = allocateGOTEntries(1); 1484 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1485 } 1486 if (Value.SymbolName) 1487 addRelocationForSymbol(RE, Value.SymbolName); 1488 else 1489 addRelocationForSection(RE, Value.SectionID); 1490 } else if (RelType == ELF::R_MIPS_26) { 1491 // This is an Mips branch relocation, need to use a stub function. 1492 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1493 SectionEntry &Section = Sections[SectionID]; 1494 1495 // Look up for existing stub. 1496 StubMap::const_iterator i = Stubs.find(Value); 1497 if (i != Stubs.end()) { 1498 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1499 addRelocationForSection(RE, SectionID); 1500 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1501 } else { 1502 // Create a new stub function. 1503 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1504 Stubs[Value] = Section.getStubOffset(); 1505 1506 unsigned AbiVariant = Obj.getPlatformFlags(); 1507 1508 uint8_t *StubTargetAddr = createStubFunction( 1509 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1510 1511 if (IsMipsN32ABI) { 1512 // Creating Hi and Lo relocations for the filled stub instructions. 1513 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1514 ELF::R_MIPS_HI16, Value.Addend); 1515 RelocationEntry RELo(SectionID, 1516 StubTargetAddr - Section.getAddress() + 4, 1517 ELF::R_MIPS_LO16, Value.Addend); 1518 if (Value.SymbolName) { 1519 addRelocationForSymbol(REHi, Value.SymbolName); 1520 addRelocationForSymbol(RELo, Value.SymbolName); 1521 } else { 1522 addRelocationForSection(REHi, Value.SectionID); 1523 addRelocationForSection(RELo, Value.SectionID); 1524 } 1525 } else { 1526 // Creating Highest, Higher, Hi and Lo relocations for the filled stub 1527 // instructions. 1528 RelocationEntry REHighest(SectionID, 1529 StubTargetAddr - Section.getAddress(), 1530 ELF::R_MIPS_HIGHEST, Value.Addend); 1531 RelocationEntry REHigher(SectionID, 1532 StubTargetAddr - Section.getAddress() + 4, 1533 ELF::R_MIPS_HIGHER, Value.Addend); 1534 RelocationEntry REHi(SectionID, 1535 StubTargetAddr - Section.getAddress() + 12, 1536 ELF::R_MIPS_HI16, Value.Addend); 1537 RelocationEntry RELo(SectionID, 1538 StubTargetAddr - Section.getAddress() + 20, 1539 ELF::R_MIPS_LO16, Value.Addend); 1540 if (Value.SymbolName) { 1541 addRelocationForSymbol(REHighest, Value.SymbolName); 1542 addRelocationForSymbol(REHigher, Value.SymbolName); 1543 addRelocationForSymbol(REHi, Value.SymbolName); 1544 addRelocationForSymbol(RELo, Value.SymbolName); 1545 } else { 1546 addRelocationForSection(REHighest, Value.SectionID); 1547 addRelocationForSection(REHigher, Value.SectionID); 1548 addRelocationForSection(REHi, Value.SectionID); 1549 addRelocationForSection(RELo, Value.SectionID); 1550 } 1551 } 1552 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1553 addRelocationForSection(RE, SectionID); 1554 Section.advanceStubOffset(getMaxStubSize()); 1555 } 1556 } else { 1557 processSimpleRelocation(SectionID, Offset, RelType, Value); 1558 } 1559 1560 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1561 if (RelType == ELF::R_PPC64_REL24) { 1562 // Determine ABI variant in use for this object. 1563 unsigned AbiVariant = Obj.getPlatformFlags(); 1564 AbiVariant &= ELF::EF_PPC64_ABI; 1565 // A PPC branch relocation will need a stub function if the target is 1566 // an external symbol (either Value.SymbolName is set, or SymType is 1567 // Symbol::ST_Unknown) or if the target address is not within the 1568 // signed 24-bits branch address. 1569 SectionEntry &Section = Sections[SectionID]; 1570 uint8_t *Target = Section.getAddressWithOffset(Offset); 1571 bool RangeOverflow = false; 1572 bool IsExtern = Value.SymbolName || SymType == SymbolRef::ST_Unknown; 1573 if (!IsExtern) { 1574 if (AbiVariant != 2) { 1575 // In the ELFv1 ABI, a function call may point to the .opd entry, 1576 // so the final symbol value is calculated based on the relocation 1577 // values in the .opd section. 1578 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1579 return std::move(Err); 1580 } else { 1581 // In the ELFv2 ABI, a function symbol may provide a local entry 1582 // point, which must be used for direct calls. 1583 if (Value.SectionID == SectionID){ 1584 uint8_t SymOther = Symbol->getOther(); 1585 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1586 } 1587 } 1588 uint8_t *RelocTarget = 1589 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1590 int64_t delta = static_cast<int64_t>(Target - RelocTarget); 1591 // If it is within 26-bits branch range, just set the branch target 1592 if (SignExtend64<26>(delta) != delta) { 1593 RangeOverflow = true; 1594 } else if ((AbiVariant != 2) || 1595 (AbiVariant == 2 && Value.SectionID == SectionID)) { 1596 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1597 addRelocationForSection(RE, Value.SectionID); 1598 } 1599 } 1600 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID) || 1601 RangeOverflow) { 1602 // It is an external symbol (either Value.SymbolName is set, or 1603 // SymType is SymbolRef::ST_Unknown) or out of range. 1604 StubMap::const_iterator i = Stubs.find(Value); 1605 if (i != Stubs.end()) { 1606 // Symbol function stub already created, just relocate to it 1607 resolveRelocation(Section, Offset, 1608 Section.getLoadAddressWithOffset(i->second), 1609 RelType, 0); 1610 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1611 } else { 1612 // Create a new stub function. 1613 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1614 Stubs[Value] = Section.getStubOffset(); 1615 uint8_t *StubTargetAddr = createStubFunction( 1616 Section.getAddressWithOffset(Section.getStubOffset()), 1617 AbiVariant); 1618 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1619 ELF::R_PPC64_ADDR64, Value.Addend); 1620 1621 // Generates the 64-bits address loads as exemplified in section 1622 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1623 // apply to the low part of the instructions, so we have to update 1624 // the offset according to the target endianness. 1625 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1626 if (!IsTargetLittleEndian) 1627 StubRelocOffset += 2; 1628 1629 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1630 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1631 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1632 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1633 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1634 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1635 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1636 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1637 1638 if (Value.SymbolName) { 1639 addRelocationForSymbol(REhst, Value.SymbolName); 1640 addRelocationForSymbol(REhr, Value.SymbolName); 1641 addRelocationForSymbol(REh, Value.SymbolName); 1642 addRelocationForSymbol(REl, Value.SymbolName); 1643 } else { 1644 addRelocationForSection(REhst, Value.SectionID); 1645 addRelocationForSection(REhr, Value.SectionID); 1646 addRelocationForSection(REh, Value.SectionID); 1647 addRelocationForSection(REl, Value.SectionID); 1648 } 1649 1650 resolveRelocation( 1651 Section, Offset, 1652 Section.getLoadAddressWithOffset(Section.getStubOffset()), 1653 RelType, 0); 1654 Section.advanceStubOffset(getMaxStubSize()); 1655 } 1656 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID)) { 1657 // Restore the TOC for external calls 1658 if (AbiVariant == 2) 1659 writeInt32BE(Target + 4, 0xE8410018); // ld r2,24(r1) 1660 else 1661 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1662 } 1663 } 1664 } else if (RelType == ELF::R_PPC64_TOC16 || 1665 RelType == ELF::R_PPC64_TOC16_DS || 1666 RelType == ELF::R_PPC64_TOC16_LO || 1667 RelType == ELF::R_PPC64_TOC16_LO_DS || 1668 RelType == ELF::R_PPC64_TOC16_HI || 1669 RelType == ELF::R_PPC64_TOC16_HA) { 1670 // These relocations are supposed to subtract the TOC address from 1671 // the final value. This does not fit cleanly into the RuntimeDyld 1672 // scheme, since there may be *two* sections involved in determining 1673 // the relocation value (the section of the symbol referred to by the 1674 // relocation, and the TOC section associated with the current module). 1675 // 1676 // Fortunately, these relocations are currently only ever generated 1677 // referring to symbols that themselves reside in the TOC, which means 1678 // that the two sections are actually the same. Thus they cancel out 1679 // and we can immediately resolve the relocation right now. 1680 switch (RelType) { 1681 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1682 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1683 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1684 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1685 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1686 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1687 default: llvm_unreachable("Wrong relocation type."); 1688 } 1689 1690 RelocationValueRef TOCValue; 1691 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1692 return std::move(Err); 1693 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1694 llvm_unreachable("Unsupported TOC relocation."); 1695 Value.Addend -= TOCValue.Addend; 1696 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1697 } else { 1698 // There are two ways to refer to the TOC address directly: either 1699 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1700 // ignored), or via any relocation that refers to the magic ".TOC." 1701 // symbols (in which case the addend is respected). 1702 if (RelType == ELF::R_PPC64_TOC) { 1703 RelType = ELF::R_PPC64_ADDR64; 1704 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1705 return std::move(Err); 1706 } else if (TargetName == ".TOC.") { 1707 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1708 return std::move(Err); 1709 Value.Addend += Addend; 1710 } 1711 1712 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1713 1714 if (Value.SymbolName) 1715 addRelocationForSymbol(RE, Value.SymbolName); 1716 else 1717 addRelocationForSection(RE, Value.SectionID); 1718 } 1719 } else if (Arch == Triple::systemz && 1720 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1721 // Create function stubs for both PLT and GOT references, regardless of 1722 // whether the GOT reference is to data or code. The stub contains the 1723 // full address of the symbol, as needed by GOT references, and the 1724 // executable part only adds an overhead of 8 bytes. 1725 // 1726 // We could try to conserve space by allocating the code and data 1727 // parts of the stub separately. However, as things stand, we allocate 1728 // a stub for every relocation, so using a GOT in JIT code should be 1729 // no less space efficient than using an explicit constant pool. 1730 LLVM_DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1731 SectionEntry &Section = Sections[SectionID]; 1732 1733 // Look for an existing stub. 1734 StubMap::const_iterator i = Stubs.find(Value); 1735 uintptr_t StubAddress; 1736 if (i != Stubs.end()) { 1737 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1738 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1739 } else { 1740 // Create a new stub function. 1741 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1742 1743 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1744 StubAddress = 1745 alignTo(BaseAddress + Section.getStubOffset(), getStubAlignment()); 1746 unsigned StubOffset = StubAddress - BaseAddress; 1747 1748 Stubs[Value] = StubOffset; 1749 createStubFunction((uint8_t *)StubAddress); 1750 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1751 Value.Offset); 1752 if (Value.SymbolName) 1753 addRelocationForSymbol(RE, Value.SymbolName); 1754 else 1755 addRelocationForSection(RE, Value.SectionID); 1756 Section.advanceStubOffset(getMaxStubSize()); 1757 } 1758 1759 if (RelType == ELF::R_390_GOTENT) 1760 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1761 Addend); 1762 else 1763 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1764 } else if (Arch == Triple::x86_64) { 1765 if (RelType == ELF::R_X86_64_PLT32) { 1766 // The way the PLT relocations normally work is that the linker allocates 1767 // the 1768 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1769 // entry will then jump to an address provided by the GOT. On first call, 1770 // the 1771 // GOT address will point back into PLT code that resolves the symbol. After 1772 // the first call, the GOT entry points to the actual function. 1773 // 1774 // For local functions we're ignoring all of that here and just replacing 1775 // the PLT32 relocation type with PC32, which will translate the relocation 1776 // into a PC-relative call directly to the function. For external symbols we 1777 // can't be sure the function will be within 2^32 bytes of the call site, so 1778 // we need to create a stub, which calls into the GOT. This case is 1779 // equivalent to the usual PLT implementation except that we use the stub 1780 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1781 // rather than allocating a PLT section. 1782 if (Value.SymbolName && MemMgr.allowStubAllocation()) { 1783 // This is a call to an external function. 1784 // Look for an existing stub. 1785 SectionEntry *Section = &Sections[SectionID]; 1786 StubMap::const_iterator i = Stubs.find(Value); 1787 uintptr_t StubAddress; 1788 if (i != Stubs.end()) { 1789 StubAddress = uintptr_t(Section->getAddress()) + i->second; 1790 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1791 } else { 1792 // Create a new stub function (equivalent to a PLT entry). 1793 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1794 1795 uintptr_t BaseAddress = uintptr_t(Section->getAddress()); 1796 StubAddress = alignTo(BaseAddress + Section->getStubOffset(), 1797 getStubAlignment()); 1798 unsigned StubOffset = StubAddress - BaseAddress; 1799 Stubs[Value] = StubOffset; 1800 createStubFunction((uint8_t *)StubAddress); 1801 1802 // Bump our stub offset counter 1803 Section->advanceStubOffset(getMaxStubSize()); 1804 1805 // Allocate a GOT Entry 1806 uint64_t GOTOffset = allocateGOTEntries(1); 1807 // This potentially creates a new Section which potentially 1808 // invalidates the Section pointer, so reload it. 1809 Section = &Sections[SectionID]; 1810 1811 // The load of the GOT address has an addend of -4 1812 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1813 ELF::R_X86_64_PC32); 1814 1815 // Fill in the value of the symbol we're targeting into the GOT 1816 addRelocationForSymbol( 1817 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1818 Value.SymbolName); 1819 } 1820 1821 // Make the target call a call into the stub table. 1822 resolveRelocation(*Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1823 Addend); 1824 } else { 1825 Value.Addend += support::ulittle32_t::ref( 1826 computePlaceholderAddress(SectionID, Offset)); 1827 processSimpleRelocation(SectionID, Offset, ELF::R_X86_64_PC32, Value); 1828 } 1829 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1830 RelType == ELF::R_X86_64_GOTPCRELX || 1831 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1832 uint64_t GOTOffset = allocateGOTEntries(1); 1833 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1834 ELF::R_X86_64_PC32); 1835 1836 // Fill in the value of the symbol we're targeting into the GOT 1837 RelocationEntry RE = 1838 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1839 if (Value.SymbolName) 1840 addRelocationForSymbol(RE, Value.SymbolName); 1841 else 1842 addRelocationForSection(RE, Value.SectionID); 1843 } else if (RelType == ELF::R_X86_64_GOT64) { 1844 // Fill in a 64-bit GOT offset. 1845 uint64_t GOTOffset = allocateGOTEntries(1); 1846 resolveRelocation(Sections[SectionID], Offset, GOTOffset, 1847 ELF::R_X86_64_64, 0); 1848 1849 // Fill in the value of the symbol we're targeting into the GOT 1850 RelocationEntry RE = 1851 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1852 if (Value.SymbolName) 1853 addRelocationForSymbol(RE, Value.SymbolName); 1854 else 1855 addRelocationForSection(RE, Value.SectionID); 1856 } else if (RelType == ELF::R_X86_64_GOTPC32) { 1857 // Materialize the address of the base of the GOT relative to the PC. 1858 // This doesn't create a GOT entry, but it does mean we need a GOT 1859 // section. 1860 (void)allocateGOTEntries(0); 1861 resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC32); 1862 } else if (RelType == ELF::R_X86_64_GOTPC64) { 1863 (void)allocateGOTEntries(0); 1864 resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC64); 1865 } else if (RelType == ELF::R_X86_64_GOTOFF64) { 1866 // GOTOFF relocations ultimately require a section difference relocation. 1867 (void)allocateGOTEntries(0); 1868 processSimpleRelocation(SectionID, Offset, RelType, Value); 1869 } else if (RelType == ELF::R_X86_64_PC32) { 1870 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1871 processSimpleRelocation(SectionID, Offset, RelType, Value); 1872 } else if (RelType == ELF::R_X86_64_PC64) { 1873 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1874 processSimpleRelocation(SectionID, Offset, RelType, Value); 1875 } else if (RelType == ELF::R_X86_64_GOTTPOFF) { 1876 processX86_64GOTTPOFFRelocation(SectionID, Offset, Value, Addend); 1877 } else if (RelType == ELF::R_X86_64_TLSGD || 1878 RelType == ELF::R_X86_64_TLSLD) { 1879 // The next relocation must be the relocation for __tls_get_addr. 1880 ++RelI; 1881 auto &GetAddrRelocation = *RelI; 1882 processX86_64TLSRelocation(SectionID, Offset, RelType, Value, Addend, 1883 GetAddrRelocation); 1884 } else { 1885 processSimpleRelocation(SectionID, Offset, RelType, Value); 1886 } 1887 } else { 1888 if (Arch == Triple::x86) { 1889 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1890 } 1891 processSimpleRelocation(SectionID, Offset, RelType, Value); 1892 } 1893 return ++RelI; 1894 } 1895 1896 void RuntimeDyldELF::processX86_64GOTTPOFFRelocation(unsigned SectionID, 1897 uint64_t Offset, 1898 RelocationValueRef Value, 1899 int64_t Addend) { 1900 // Use the approach from "x86-64 Linker Optimizations" from the TLS spec 1901 // to replace the GOTTPOFF relocation with a TPOFF relocation. The spec 1902 // only mentions one optimization even though there are two different 1903 // code sequences for the Initial Exec TLS Model. We match the code to 1904 // find out which one was used. 1905 1906 // A possible TLS code sequence and its replacement 1907 struct CodeSequence { 1908 // The expected code sequence 1909 ArrayRef<uint8_t> ExpectedCodeSequence; 1910 // The negative offset of the GOTTPOFF relocation to the beginning of 1911 // the sequence 1912 uint64_t TLSSequenceOffset; 1913 // The new code sequence 1914 ArrayRef<uint8_t> NewCodeSequence; 1915 // The offset of the new TPOFF relocation 1916 uint64_t TpoffRelocationOffset; 1917 }; 1918 1919 std::array<CodeSequence, 2> CodeSequences; 1920 1921 // Initial Exec Code Model Sequence 1922 { 1923 static const std::initializer_list<uint8_t> ExpectedCodeSequenceList = { 1924 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 1925 0x00, // mov %fs:0, %rax 1926 0x48, 0x03, 0x05, 0x00, 0x00, 0x00, 0x00 // add x@gotpoff(%rip), 1927 // %rax 1928 }; 1929 CodeSequences[0].ExpectedCodeSequence = 1930 ArrayRef<uint8_t>(ExpectedCodeSequenceList); 1931 CodeSequences[0].TLSSequenceOffset = 12; 1932 1933 static const std::initializer_list<uint8_t> NewCodeSequenceList = { 1934 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0, %rax 1935 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff(%rax), %rax 1936 }; 1937 CodeSequences[0].NewCodeSequence = ArrayRef<uint8_t>(NewCodeSequenceList); 1938 CodeSequences[0].TpoffRelocationOffset = 12; 1939 } 1940 1941 // Initial Exec Code Model Sequence, II 1942 { 1943 static const std::initializer_list<uint8_t> ExpectedCodeSequenceList = { 1944 0x48, 0x8b, 0x05, 0x00, 0x00, 0x00, 0x00, // mov x@gotpoff(%rip), %rax 1945 0x64, 0x48, 0x8b, 0x00, 0x00, 0x00, 0x00 // mov %fs:(%rax), %rax 1946 }; 1947 CodeSequences[1].ExpectedCodeSequence = 1948 ArrayRef<uint8_t>(ExpectedCodeSequenceList); 1949 CodeSequences[1].TLSSequenceOffset = 3; 1950 1951 static const std::initializer_list<uint8_t> NewCodeSequenceList = { 1952 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00, // 6 byte nop 1953 0x64, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:x@tpoff, %rax 1954 }; 1955 CodeSequences[1].NewCodeSequence = ArrayRef<uint8_t>(NewCodeSequenceList); 1956 CodeSequences[1].TpoffRelocationOffset = 10; 1957 } 1958 1959 bool Resolved = false; 1960 auto &Section = Sections[SectionID]; 1961 for (const auto &C : CodeSequences) { 1962 assert(C.ExpectedCodeSequence.size() == C.NewCodeSequence.size() && 1963 "Old and new code sequences must have the same size"); 1964 1965 if (Offset < C.TLSSequenceOffset || 1966 (Offset - C.TLSSequenceOffset + C.NewCodeSequence.size()) > 1967 Section.getSize()) { 1968 // This can't be a matching sequence as it doesn't fit in the current 1969 // section 1970 continue; 1971 } 1972 1973 auto TLSSequenceStartOffset = Offset - C.TLSSequenceOffset; 1974 auto *TLSSequence = Section.getAddressWithOffset(TLSSequenceStartOffset); 1975 if (ArrayRef<uint8_t>(TLSSequence, C.ExpectedCodeSequence.size()) != 1976 C.ExpectedCodeSequence) { 1977 continue; 1978 } 1979 1980 memcpy(TLSSequence, C.NewCodeSequence.data(), C.NewCodeSequence.size()); 1981 1982 // The original GOTTPOFF relocation has an addend as it is PC relative, 1983 // so it needs to be corrected. The TPOFF32 relocation is used as an 1984 // absolute value (which is an offset from %fs:0), so remove the addend 1985 // again. 1986 RelocationEntry RE(SectionID, 1987 TLSSequenceStartOffset + C.TpoffRelocationOffset, 1988 ELF::R_X86_64_TPOFF32, Value.Addend - Addend); 1989 1990 if (Value.SymbolName) 1991 addRelocationForSymbol(RE, Value.SymbolName); 1992 else 1993 addRelocationForSection(RE, Value.SectionID); 1994 1995 Resolved = true; 1996 break; 1997 } 1998 1999 if (!Resolved) { 2000 // The GOTTPOFF relocation was not used in one of the sequences 2001 // described in the spec, so we can't optimize it to a TPOFF 2002 // relocation. 2003 uint64_t GOTOffset = allocateGOTEntries(1); 2004 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 2005 ELF::R_X86_64_PC32); 2006 RelocationEntry RE = 2007 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_TPOFF64); 2008 if (Value.SymbolName) 2009 addRelocationForSymbol(RE, Value.SymbolName); 2010 else 2011 addRelocationForSection(RE, Value.SectionID); 2012 } 2013 } 2014 2015 void RuntimeDyldELF::processX86_64TLSRelocation( 2016 unsigned SectionID, uint64_t Offset, uint64_t RelType, 2017 RelocationValueRef Value, int64_t Addend, 2018 const RelocationRef &GetAddrRelocation) { 2019 // Since we are statically linking and have no additional DSOs, we can resolve 2020 // the relocation directly without using __tls_get_addr. 2021 // Use the approach from "x86-64 Linker Optimizations" from the TLS spec 2022 // to replace it with the Local Exec relocation variant. 2023 2024 // Find out whether the code was compiled with the large or small memory 2025 // model. For this we look at the next relocation which is the relocation 2026 // for the __tls_get_addr function. If it's a 32 bit relocation, it's the 2027 // small code model, with a 64 bit relocation it's the large code model. 2028 bool IsSmallCodeModel; 2029 // Is the relocation for the __tls_get_addr a PC-relative GOT relocation? 2030 bool IsGOTPCRel = false; 2031 2032 switch (GetAddrRelocation.getType()) { 2033 case ELF::R_X86_64_GOTPCREL: 2034 case ELF::R_X86_64_REX_GOTPCRELX: 2035 case ELF::R_X86_64_GOTPCRELX: 2036 IsGOTPCRel = true; 2037 [[fallthrough]]; 2038 case ELF::R_X86_64_PLT32: 2039 IsSmallCodeModel = true; 2040 break; 2041 case ELF::R_X86_64_PLTOFF64: 2042 IsSmallCodeModel = false; 2043 break; 2044 default: 2045 report_fatal_error( 2046 "invalid TLS relocations for General/Local Dynamic TLS Model: " 2047 "expected PLT or GOT relocation for __tls_get_addr function"); 2048 } 2049 2050 // The negative offset to the start of the TLS code sequence relative to 2051 // the offset of the TLSGD/TLSLD relocation 2052 uint64_t TLSSequenceOffset; 2053 // The expected start of the code sequence 2054 ArrayRef<uint8_t> ExpectedCodeSequence; 2055 // The new TLS code sequence that will replace the existing code 2056 ArrayRef<uint8_t> NewCodeSequence; 2057 2058 if (RelType == ELF::R_X86_64_TLSGD) { 2059 // The offset of the new TPOFF32 relocation (offset starting from the 2060 // beginning of the whole TLS sequence) 2061 uint64_t TpoffRelocOffset; 2062 2063 if (IsSmallCodeModel) { 2064 if (!IsGOTPCRel) { 2065 static const std::initializer_list<uint8_t> CodeSequence = { 2066 0x66, // data16 (no-op prefix) 2067 0x48, 0x8d, 0x3d, 0x00, 0x00, 2068 0x00, 0x00, // lea <disp32>(%rip), %rdi 2069 0x66, 0x66, // two data16 prefixes 2070 0x48, // rex64 (no-op prefix) 2071 0xe8, 0x00, 0x00, 0x00, 0x00 // call __tls_get_addr@plt 2072 }; 2073 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2074 TLSSequenceOffset = 4; 2075 } else { 2076 // This code sequence is not described in the TLS spec but gcc 2077 // generates it sometimes. 2078 static const std::initializer_list<uint8_t> CodeSequence = { 2079 0x66, // data16 (no-op prefix) 2080 0x48, 0x8d, 0x3d, 0x00, 0x00, 2081 0x00, 0x00, // lea <disp32>(%rip), %rdi 2082 0x66, // data16 prefix (no-op prefix) 2083 0x48, // rex64 (no-op prefix) 2084 0xff, 0x15, 0x00, 0x00, 0x00, 2085 0x00 // call *__tls_get_addr@gotpcrel(%rip) 2086 }; 2087 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2088 TLSSequenceOffset = 4; 2089 } 2090 2091 // The replacement code for the small code model. It's the same for 2092 // both sequences. 2093 static const std::initializer_list<uint8_t> SmallSequence = { 2094 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 2095 0x00, // mov %fs:0, %rax 2096 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff(%rax), 2097 // %rax 2098 }; 2099 NewCodeSequence = ArrayRef<uint8_t>(SmallSequence); 2100 TpoffRelocOffset = 12; 2101 } else { 2102 static const std::initializer_list<uint8_t> CodeSequence = { 2103 0x48, 0x8d, 0x3d, 0x00, 0x00, 0x00, 0x00, // lea <disp32>(%rip), 2104 // %rdi 2105 0x48, 0xb8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 2106 0x00, // movabs $__tls_get_addr@pltoff, %rax 2107 0x48, 0x01, 0xd8, // add %rbx, %rax 2108 0xff, 0xd0 // call *%rax 2109 }; 2110 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2111 TLSSequenceOffset = 3; 2112 2113 // The replacement code for the large code model 2114 static const std::initializer_list<uint8_t> LargeSequence = { 2115 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 2116 0x00, // mov %fs:0, %rax 2117 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00, // lea x@tpoff(%rax), 2118 // %rax 2119 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00 // nopw 0x0(%rax,%rax,1) 2120 }; 2121 NewCodeSequence = ArrayRef<uint8_t>(LargeSequence); 2122 TpoffRelocOffset = 12; 2123 } 2124 2125 // The TLSGD/TLSLD relocations are PC-relative, so they have an addend. 2126 // The new TPOFF32 relocations is used as an absolute offset from 2127 // %fs:0, so remove the TLSGD/TLSLD addend again. 2128 RelocationEntry RE(SectionID, Offset - TLSSequenceOffset + TpoffRelocOffset, 2129 ELF::R_X86_64_TPOFF32, Value.Addend - Addend); 2130 if (Value.SymbolName) 2131 addRelocationForSymbol(RE, Value.SymbolName); 2132 else 2133 addRelocationForSection(RE, Value.SectionID); 2134 } else if (RelType == ELF::R_X86_64_TLSLD) { 2135 if (IsSmallCodeModel) { 2136 if (!IsGOTPCRel) { 2137 static const std::initializer_list<uint8_t> CodeSequence = { 2138 0x48, 0x8d, 0x3d, 0x00, 0x00, 0x00, // leaq <disp32>(%rip), %rdi 2139 0x00, 0xe8, 0x00, 0x00, 0x00, 0x00 // call __tls_get_addr@plt 2140 }; 2141 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2142 TLSSequenceOffset = 3; 2143 2144 // The replacement code for the small code model 2145 static const std::initializer_list<uint8_t> SmallSequence = { 2146 0x66, 0x66, 0x66, // three data16 prefixes (no-op) 2147 0x64, 0x48, 0x8b, 0x04, 0x25, 2148 0x00, 0x00, 0x00, 0x00 // mov %fs:0, %rax 2149 }; 2150 NewCodeSequence = ArrayRef<uint8_t>(SmallSequence); 2151 } else { 2152 // This code sequence is not described in the TLS spec but gcc 2153 // generates it sometimes. 2154 static const std::initializer_list<uint8_t> CodeSequence = { 2155 0x48, 0x8d, 0x3d, 0x00, 2156 0x00, 0x00, 0x00, // leaq <disp32>(%rip), %rdi 2157 0xff, 0x15, 0x00, 0x00, 2158 0x00, 0x00 // call 2159 // *__tls_get_addr@gotpcrel(%rip) 2160 }; 2161 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2162 TLSSequenceOffset = 3; 2163 2164 // The replacement is code is just like above but it needs to be 2165 // one byte longer. 2166 static const std::initializer_list<uint8_t> SmallSequence = { 2167 0x0f, 0x1f, 0x40, 0x00, // 4 byte nop 2168 0x64, 0x48, 0x8b, 0x04, 0x25, 2169 0x00, 0x00, 0x00, 0x00 // mov %fs:0, %rax 2170 }; 2171 NewCodeSequence = ArrayRef<uint8_t>(SmallSequence); 2172 } 2173 } else { 2174 // This is the same sequence as for the TLSGD sequence with the large 2175 // memory model above 2176 static const std::initializer_list<uint8_t> CodeSequence = { 2177 0x48, 0x8d, 0x3d, 0x00, 0x00, 0x00, 0x00, // lea <disp32>(%rip), 2178 // %rdi 2179 0x48, 0xb8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 2180 0x48, // movabs $__tls_get_addr@pltoff, %rax 2181 0x01, 0xd8, // add %rbx, %rax 2182 0xff, 0xd0 // call *%rax 2183 }; 2184 ExpectedCodeSequence = ArrayRef<uint8_t>(CodeSequence); 2185 TLSSequenceOffset = 3; 2186 2187 // The replacement code for the large code model 2188 static const std::initializer_list<uint8_t> LargeSequence = { 2189 0x66, 0x66, 0x66, // three data16 prefixes (no-op) 2190 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 2191 0x00, // 10 byte nop 2192 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00 // mov %fs:0,%rax 2193 }; 2194 NewCodeSequence = ArrayRef<uint8_t>(LargeSequence); 2195 } 2196 } else { 2197 llvm_unreachable("both TLS relocations handled above"); 2198 } 2199 2200 assert(ExpectedCodeSequence.size() == NewCodeSequence.size() && 2201 "Old and new code sequences must have the same size"); 2202 2203 auto &Section = Sections[SectionID]; 2204 if (Offset < TLSSequenceOffset || 2205 (Offset - TLSSequenceOffset + NewCodeSequence.size()) > 2206 Section.getSize()) { 2207 report_fatal_error("unexpected end of section in TLS sequence"); 2208 } 2209 2210 auto *TLSSequence = Section.getAddressWithOffset(Offset - TLSSequenceOffset); 2211 if (ArrayRef<uint8_t>(TLSSequence, ExpectedCodeSequence.size()) != 2212 ExpectedCodeSequence) { 2213 report_fatal_error( 2214 "invalid TLS sequence for Global/Local Dynamic TLS Model"); 2215 } 2216 2217 memcpy(TLSSequence, NewCodeSequence.data(), NewCodeSequence.size()); 2218 } 2219 2220 size_t RuntimeDyldELF::getGOTEntrySize() { 2221 // We don't use the GOT in all of these cases, but it's essentially free 2222 // to put them all here. 2223 size_t Result = 0; 2224 switch (Arch) { 2225 case Triple::x86_64: 2226 case Triple::aarch64: 2227 case Triple::aarch64_be: 2228 case Triple::ppc64: 2229 case Triple::ppc64le: 2230 case Triple::systemz: 2231 Result = sizeof(uint64_t); 2232 break; 2233 case Triple::x86: 2234 case Triple::arm: 2235 case Triple::thumb: 2236 Result = sizeof(uint32_t); 2237 break; 2238 case Triple::mips: 2239 case Triple::mipsel: 2240 case Triple::mips64: 2241 case Triple::mips64el: 2242 if (IsMipsO32ABI || IsMipsN32ABI) 2243 Result = sizeof(uint32_t); 2244 else if (IsMipsN64ABI) 2245 Result = sizeof(uint64_t); 2246 else 2247 llvm_unreachable("Mips ABI not handled"); 2248 break; 2249 default: 2250 llvm_unreachable("Unsupported CPU type!"); 2251 } 2252 return Result; 2253 } 2254 2255 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 2256 if (GOTSectionID == 0) { 2257 GOTSectionID = Sections.size(); 2258 // Reserve a section id. We'll allocate the section later 2259 // once we know the total size 2260 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 2261 } 2262 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 2263 CurrentGOTIndex += no; 2264 return StartOffset; 2265 } 2266 2267 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 2268 unsigned GOTRelType) { 2269 auto E = GOTOffsetMap.insert({Value, 0}); 2270 if (E.second) { 2271 uint64_t GOTOffset = allocateGOTEntries(1); 2272 2273 // Create relocation for newly created GOT entry 2274 RelocationEntry RE = 2275 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 2276 if (Value.SymbolName) 2277 addRelocationForSymbol(RE, Value.SymbolName); 2278 else 2279 addRelocationForSection(RE, Value.SectionID); 2280 2281 E.first->second = GOTOffset; 2282 } 2283 2284 return E.first->second; 2285 } 2286 2287 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 2288 uint64_t Offset, 2289 uint64_t GOTOffset, 2290 uint32_t Type) { 2291 // Fill in the relative address of the GOT Entry into the stub 2292 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 2293 addRelocationForSection(GOTRE, GOTSectionID); 2294 } 2295 2296 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 2297 uint64_t SymbolOffset, 2298 uint32_t Type) { 2299 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 2300 } 2301 2302 void RuntimeDyldELF::processNewSymbol(const SymbolRef &ObjSymbol, SymbolTableEntry& Symbol) { 2303 // This should never return an error as `processNewSymbol` wouldn't have been 2304 // called if getFlags() returned an error before. 2305 auto ObjSymbolFlags = cantFail(ObjSymbol.getFlags()); 2306 2307 if (ObjSymbolFlags & SymbolRef::SF_Indirect) { 2308 if (IFuncStubSectionID == 0) { 2309 // Create a dummy section for the ifunc stubs. It will be actually 2310 // allocated in finalizeLoad() below. 2311 IFuncStubSectionID = Sections.size(); 2312 Sections.push_back( 2313 SectionEntry(".text.__llvm_IFuncStubs", nullptr, 0, 0, 0)); 2314 // First 64B are reserverd for the IFunc resolver 2315 IFuncStubOffset = 64; 2316 } 2317 2318 IFuncStubs.push_back(IFuncStub{IFuncStubOffset, Symbol}); 2319 // Modify the symbol so that it points to the ifunc stub instead of to the 2320 // resolver function. 2321 Symbol = SymbolTableEntry(IFuncStubSectionID, IFuncStubOffset, 2322 Symbol.getFlags()); 2323 IFuncStubOffset += getMaxIFuncStubSize(); 2324 } 2325 } 2326 2327 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 2328 ObjSectionToIDMap &SectionMap) { 2329 if (IsMipsO32ABI) 2330 if (!PendingRelocs.empty()) 2331 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 2332 2333 // Create the IFunc stubs if necessary. This must be done before processing 2334 // the GOT entries, as the IFunc stubs may create some. 2335 if (IFuncStubSectionID != 0) { 2336 uint8_t *IFuncStubsAddr = MemMgr.allocateCodeSection( 2337 IFuncStubOffset, 1, IFuncStubSectionID, ".text.__llvm_IFuncStubs"); 2338 if (!IFuncStubsAddr) 2339 return make_error<RuntimeDyldError>( 2340 "Unable to allocate memory for IFunc stubs!"); 2341 Sections[IFuncStubSectionID] = 2342 SectionEntry(".text.__llvm_IFuncStubs", IFuncStubsAddr, IFuncStubOffset, 2343 IFuncStubOffset, 0); 2344 2345 createIFuncResolver(IFuncStubsAddr); 2346 2347 LLVM_DEBUG(dbgs() << "Creating IFunc stubs SectionID: " 2348 << IFuncStubSectionID << " Addr: " 2349 << Sections[IFuncStubSectionID].getAddress() << '\n'); 2350 for (auto &IFuncStub : IFuncStubs) { 2351 auto &Symbol = IFuncStub.OriginalSymbol; 2352 LLVM_DEBUG(dbgs() << "\tSectionID: " << Symbol.getSectionID() 2353 << " Offset: " << format("%p", Symbol.getOffset()) 2354 << " IFuncStubOffset: " 2355 << format("%p\n", IFuncStub.StubOffset)); 2356 createIFuncStub(IFuncStubSectionID, 0, IFuncStub.StubOffset, 2357 Symbol.getSectionID(), Symbol.getOffset()); 2358 } 2359 2360 IFuncStubSectionID = 0; 2361 IFuncStubOffset = 0; 2362 IFuncStubs.clear(); 2363 } 2364 2365 // If necessary, allocate the global offset table 2366 if (GOTSectionID != 0) { 2367 // Allocate memory for the section 2368 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 2369 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 2370 GOTSectionID, ".got", false); 2371 if (!Addr) 2372 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 2373 2374 Sections[GOTSectionID] = 2375 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 2376 2377 // For now, initialize all GOT entries to zero. We'll fill them in as 2378 // needed when GOT-based relocations are applied. 2379 memset(Addr, 0, TotalSize); 2380 if (IsMipsN32ABI || IsMipsN64ABI) { 2381 // To correctly resolve Mips GOT relocations, we need a mapping from 2382 // object's sections to GOTs. 2383 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 2384 SI != SE; ++SI) { 2385 if (SI->relocation_begin() != SI->relocation_end()) { 2386 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection(); 2387 if (!RelSecOrErr) 2388 return make_error<RuntimeDyldError>( 2389 toString(RelSecOrErr.takeError())); 2390 2391 section_iterator RelocatedSection = *RelSecOrErr; 2392 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 2393 assert(i != SectionMap.end()); 2394 SectionToGOTMap[i->second] = GOTSectionID; 2395 } 2396 } 2397 GOTSymbolOffsets.clear(); 2398 } 2399 } 2400 2401 // Look for and record the EH frame section. 2402 ObjSectionToIDMap::iterator i, e; 2403 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 2404 const SectionRef &Section = i->first; 2405 2406 StringRef Name; 2407 Expected<StringRef> NameOrErr = Section.getName(); 2408 if (NameOrErr) 2409 Name = *NameOrErr; 2410 else 2411 consumeError(NameOrErr.takeError()); 2412 2413 if (Name == ".eh_frame") { 2414 UnregisteredEHFrameSections.push_back(i->second); 2415 break; 2416 } 2417 } 2418 2419 GOTOffsetMap.clear(); 2420 GOTSectionID = 0; 2421 CurrentGOTIndex = 0; 2422 2423 return Error::success(); 2424 } 2425 2426 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 2427 return Obj.isELF(); 2428 } 2429 2430 void RuntimeDyldELF::createIFuncResolver(uint8_t *Addr) const { 2431 if (Arch == Triple::x86_64) { 2432 // The adddres of the GOT1 entry is in %r11, the GOT2 entry is in %r11+8 2433 // (see createIFuncStub() for details) 2434 // The following code first saves all registers that contain the original 2435 // function arguments as those registers are not saved by the resolver 2436 // function. %r11 is saved as well so that the GOT2 entry can be updated 2437 // afterwards. Then it calls the actual IFunc resolver function whose 2438 // address is stored in GOT2. After the resolver function returns, all 2439 // saved registers are restored and the return value is written to GOT1. 2440 // Finally, jump to the now resolved function. 2441 // clang-format off 2442 const uint8_t StubCode[] = { 2443 0x57, // push %rdi 2444 0x56, // push %rsi 2445 0x52, // push %rdx 2446 0x51, // push %rcx 2447 0x41, 0x50, // push %r8 2448 0x41, 0x51, // push %r9 2449 0x41, 0x53, // push %r11 2450 0x41, 0xff, 0x53, 0x08, // call *0x8(%r11) 2451 0x41, 0x5b, // pop %r11 2452 0x41, 0x59, // pop %r9 2453 0x41, 0x58, // pop %r8 2454 0x59, // pop %rcx 2455 0x5a, // pop %rdx 2456 0x5e, // pop %rsi 2457 0x5f, // pop %rdi 2458 0x49, 0x89, 0x03, // mov %rax,(%r11) 2459 0xff, 0xe0 // jmp *%rax 2460 }; 2461 // clang-format on 2462 static_assert(sizeof(StubCode) <= 64, 2463 "maximum size of the IFunc resolver is 64B"); 2464 memcpy(Addr, StubCode, sizeof(StubCode)); 2465 } else { 2466 report_fatal_error( 2467 "IFunc resolver is not supported for target architecture"); 2468 } 2469 } 2470 2471 void RuntimeDyldELF::createIFuncStub(unsigned IFuncStubSectionID, 2472 uint64_t IFuncResolverOffset, 2473 uint64_t IFuncStubOffset, 2474 unsigned IFuncSectionID, 2475 uint64_t IFuncOffset) { 2476 auto &IFuncStubSection = Sections[IFuncStubSectionID]; 2477 auto *Addr = IFuncStubSection.getAddressWithOffset(IFuncStubOffset); 2478 2479 if (Arch == Triple::x86_64) { 2480 // The first instruction loads a PC-relative address into %r11 which is a 2481 // GOT entry for this stub. This initially contains the address to the 2482 // IFunc resolver. We can use %r11 here as it's caller saved but not used 2483 // to pass any arguments. In fact, x86_64 ABI even suggests using %r11 for 2484 // code in the PLT. The IFunc resolver will use %r11 to update the GOT 2485 // entry. 2486 // 2487 // The next instruction just jumps to the address contained in the GOT 2488 // entry. As mentioned above, we do this two-step jump by first setting 2489 // %r11 so that the IFunc resolver has access to it. 2490 // 2491 // The IFunc resolver of course also needs to know the actual address of 2492 // the actual IFunc resolver function. This will be stored in a GOT entry 2493 // right next to the first one for this stub. So, the IFunc resolver will 2494 // be able to call it with %r11+8. 2495 // 2496 // In total, two adjacent GOT entries (+relocation) and one additional 2497 // relocation are required: 2498 // GOT1: Address of the IFunc resolver. 2499 // GOT2: Address of the IFunc resolver function. 2500 // IFuncStubOffset+3: 32-bit PC-relative address of GOT1. 2501 uint64_t GOT1 = allocateGOTEntries(2); 2502 uint64_t GOT2 = GOT1 + getGOTEntrySize(); 2503 2504 RelocationEntry RE1(GOTSectionID, GOT1, ELF::R_X86_64_64, 2505 IFuncResolverOffset, {}); 2506 addRelocationForSection(RE1, IFuncStubSectionID); 2507 RelocationEntry RE2(GOTSectionID, GOT2, ELF::R_X86_64_64, IFuncOffset, {}); 2508 addRelocationForSection(RE2, IFuncSectionID); 2509 2510 const uint8_t StubCode[] = { 2511 0x4c, 0x8d, 0x1d, 0x00, 0x00, 0x00, 0x00, // leaq 0x0(%rip),%r11 2512 0x41, 0xff, 0x23 // jmpq *(%r11) 2513 }; 2514 assert(sizeof(StubCode) <= getMaxIFuncStubSize() && 2515 "IFunc stub size must not exceed getMaxIFuncStubSize()"); 2516 memcpy(Addr, StubCode, sizeof(StubCode)); 2517 2518 // The PC-relative value starts 4 bytes from the end of the leaq 2519 // instruction, so the addend is -4. 2520 resolveGOTOffsetRelocation(IFuncStubSectionID, IFuncStubOffset + 3, 2521 GOT1 - 4, ELF::R_X86_64_PC32); 2522 } else { 2523 report_fatal_error("IFunc stub is not supported for target architecture"); 2524 } 2525 } 2526 2527 unsigned RuntimeDyldELF::getMaxIFuncStubSize() const { 2528 if (Arch == Triple::x86_64) { 2529 return 10; 2530 } 2531 return 0; 2532 } 2533 2534 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 2535 unsigned RelTy = R.getType(); 2536 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 2537 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 2538 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 2539 2540 if (Arch == Triple::x86_64) 2541 return RelTy == ELF::R_X86_64_GOTPCREL || 2542 RelTy == ELF::R_X86_64_GOTPCRELX || 2543 RelTy == ELF::R_X86_64_GOT64 || 2544 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 2545 return false; 2546 } 2547 2548 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 2549 if (Arch != Triple::x86_64) 2550 return true; // Conservative answer 2551 2552 switch (R.getType()) { 2553 default: 2554 return true; // Conservative answer 2555 2556 2557 case ELF::R_X86_64_GOTPCREL: 2558 case ELF::R_X86_64_GOTPCRELX: 2559 case ELF::R_X86_64_REX_GOTPCRELX: 2560 case ELF::R_X86_64_GOTPC64: 2561 case ELF::R_X86_64_GOT64: 2562 case ELF::R_X86_64_GOTOFF64: 2563 case ELF::R_X86_64_PC32: 2564 case ELF::R_X86_64_PC64: 2565 case ELF::R_X86_64_64: 2566 // We know that these reloation types won't need a stub function. This list 2567 // can be extended as needed. 2568 return false; 2569 } 2570 } 2571 2572 } // namespace llvm 2573