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