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 Elf_Shdr_Impl<ELFT> Elf_Shdr; 61 typedef Elf_Sym_Impl<ELFT> Elf_Sym; 62 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel; 63 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela; 64 65 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; 66 67 typedef typename ELFT::uint addr_type; 68 69 DyldELFObject(ELFObjectFile<ELFT> &&Obj); 70 71 public: 72 static Expected<std::unique_ptr<DyldELFObject>> 73 create(MemoryBufferRef Wrapper); 74 75 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 76 77 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); 78 79 // Methods for type inquiry through isa, cast and dyn_cast 80 static bool classof(const Binary *v) { 81 return (isa<ELFObjectFile<ELFT>>(v) && 82 classof(cast<ELFObjectFile<ELFT>>(v))); 83 } 84 static bool classof(const ELFObjectFile<ELFT> *v) { 85 return v->isDyldType(); 86 } 87 }; 88 89 90 91 // The MemoryBuffer passed into this constructor is just a wrapper around the 92 // actual memory. Ultimately, the Binary parent class will take ownership of 93 // this MemoryBuffer object but not the underlying memory. 94 template <class ELFT> 95 DyldELFObject<ELFT>::DyldELFObject(ELFObjectFile<ELFT> &&Obj) 96 : ELFObjectFile<ELFT>(std::move(Obj)) { 97 this->isDyldELFObject = true; 98 } 99 100 template <class ELFT> 101 Expected<std::unique_ptr<DyldELFObject<ELFT>>> 102 DyldELFObject<ELFT>::create(MemoryBufferRef Wrapper) { 103 auto Obj = ELFObjectFile<ELFT>::create(Wrapper); 104 if (auto E = Obj.takeError()) 105 return std::move(E); 106 std::unique_ptr<DyldELFObject<ELFT>> Ret( 107 new DyldELFObject<ELFT>(std::move(*Obj))); 108 return std::move(Ret); 109 } 110 111 template <class ELFT> 112 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 113 uint64_t Addr) { 114 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 115 Elf_Shdr *shdr = 116 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 117 118 // This assumes the address passed in matches the target address bitness 119 // The template-based type cast handles everything else. 120 shdr->sh_addr = static_cast<addr_type>(Addr); 121 } 122 123 template <class ELFT> 124 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 125 uint64_t Addr) { 126 127 Elf_Sym *sym = const_cast<Elf_Sym *>( 128 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 129 130 // This assumes the address passed in matches the target address bitness 131 // The template-based type cast handles everything else. 132 sym->st_value = static_cast<addr_type>(Addr); 133 } 134 135 class LoadedELFObjectInfo final 136 : public LoadedObjectInfoHelper<LoadedELFObjectInfo, 137 RuntimeDyld::LoadedObjectInfo> { 138 public: 139 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap) 140 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {} 141 142 OwningBinary<ObjectFile> 143 getObjectForDebug(const ObjectFile &Obj) const override; 144 }; 145 146 template <typename ELFT> 147 static Expected<std::unique_ptr<DyldELFObject<ELFT>>> 148 createRTDyldELFObject(MemoryBufferRef Buffer, const ObjectFile &SourceObject, 149 const LoadedELFObjectInfo &L) { 150 typedef typename ELFT::Shdr Elf_Shdr; 151 typedef typename ELFT::uint addr_type; 152 153 Expected<std::unique_ptr<DyldELFObject<ELFT>>> ObjOrErr = 154 DyldELFObject<ELFT>::create(Buffer); 155 if (Error E = ObjOrErr.takeError()) 156 return std::move(E); 157 158 std::unique_ptr<DyldELFObject<ELFT>> Obj = std::move(*ObjOrErr); 159 160 // Iterate over all sections in the object. 161 auto SI = SourceObject.section_begin(); 162 for (const auto &Sec : Obj->sections()) { 163 Expected<StringRef> NameOrErr = Sec.getName(); 164 if (!NameOrErr) { 165 consumeError(NameOrErr.takeError()); 166 continue; 167 } 168 169 if (*NameOrErr != "") { 170 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 171 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 172 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 173 174 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { 175 // This assumes that the address passed in matches the target address 176 // bitness. The template-based type cast handles everything else. 177 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 178 } 179 } 180 ++SI; 181 } 182 183 return std::move(Obj); 184 } 185 186 static OwningBinary<ObjectFile> 187 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) { 188 assert(Obj.isELF() && "Not an ELF object file."); 189 190 std::unique_ptr<MemoryBuffer> Buffer = 191 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 192 193 Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr); 194 handleAllErrors(DebugObj.takeError()); 195 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) 196 DebugObj = 197 createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L); 198 else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) 199 DebugObj = 200 createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L); 201 else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) 202 DebugObj = 203 createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L); 204 else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) 205 DebugObj = 206 createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L); 207 else 208 llvm_unreachable("Unexpected ELF format"); 209 210 handleAllErrors(DebugObj.takeError()); 211 return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer)); 212 } 213 214 OwningBinary<ObjectFile> 215 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 216 return createELFDebugObject(Obj, *this); 217 } 218 219 } // anonymous namespace 220 221 namespace llvm { 222 223 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 224 JITSymbolResolver &Resolver) 225 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 226 RuntimeDyldELF::~RuntimeDyldELF() {} 227 228 void RuntimeDyldELF::registerEHFrames() { 229 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { 230 SID EHFrameSID = UnregisteredEHFrameSections[i]; 231 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 232 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 233 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 234 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 235 } 236 UnregisteredEHFrameSections.clear(); 237 } 238 239 std::unique_ptr<RuntimeDyldELF> 240 llvm::RuntimeDyldELF::create(Triple::ArchType Arch, 241 RuntimeDyld::MemoryManager &MemMgr, 242 JITSymbolResolver &Resolver) { 243 switch (Arch) { 244 default: 245 return std::make_unique<RuntimeDyldELF>(MemMgr, Resolver); 246 case Triple::mips: 247 case Triple::mipsel: 248 case Triple::mips64: 249 case Triple::mips64el: 250 return std::make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); 251 } 252 } 253 254 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 255 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 256 if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) 257 return std::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); 258 else { 259 HasError = true; 260 raw_string_ostream ErrStream(ErrorStr); 261 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream); 262 return nullptr; 263 } 264 } 265 266 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 267 uint64_t Offset, uint64_t Value, 268 uint32_t Type, int64_t Addend, 269 uint64_t SymOffset) { 270 switch (Type) { 271 default: 272 llvm_unreachable("Relocation type not implemented yet!"); 273 break; 274 case ELF::R_X86_64_NONE: 275 break; 276 case ELF::R_X86_64_64: { 277 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 278 Value + Addend; 279 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 280 << format("%p\n", Section.getAddressWithOffset(Offset))); 281 break; 282 } 283 case ELF::R_X86_64_32: 284 case ELF::R_X86_64_32S: { 285 Value += Addend; 286 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 287 (Type == ELF::R_X86_64_32S && 288 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 289 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 290 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 291 TruncatedAddr; 292 LLVM_DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 293 << format("%p\n", Section.getAddressWithOffset(Offset))); 294 break; 295 } 296 case ELF::R_X86_64_PC8: { 297 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 298 int64_t RealOffset = Value + Addend - FinalAddress; 299 assert(isInt<8>(RealOffset)); 300 int8_t TruncOffset = (RealOffset & 0xFF); 301 Section.getAddress()[Offset] = TruncOffset; 302 break; 303 } 304 case ELF::R_X86_64_PC32: { 305 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 306 int64_t RealOffset = Value + Addend - FinalAddress; 307 assert(isInt<32>(RealOffset)); 308 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 309 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 310 TruncOffset; 311 break; 312 } 313 case ELF::R_X86_64_PC64: { 314 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 315 int64_t RealOffset = Value + Addend - FinalAddress; 316 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 317 RealOffset; 318 LLVM_DEBUG(dbgs() << "Writing " << format("%p", RealOffset) << " at " 319 << format("%p\n", FinalAddress)); 320 break; 321 } 322 case ELF::R_X86_64_GOTOFF64: { 323 // Compute Value - GOTBase. 324 uint64_t GOTBase = 0; 325 for (const auto &Section : Sections) { 326 if (Section.getName() == ".got") { 327 GOTBase = Section.getLoadAddressWithOffset(0); 328 break; 329 } 330 } 331 assert(GOTBase != 0 && "missing GOT"); 332 int64_t GOTOffset = Value - GOTBase + Addend; 333 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = GOTOffset; 334 break; 335 } 336 } 337 } 338 339 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 340 uint64_t Offset, uint32_t Value, 341 uint32_t Type, int32_t Addend) { 342 switch (Type) { 343 case ELF::R_386_32: { 344 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 345 Value + Addend; 346 break; 347 } 348 // Handle R_386_PLT32 like R_386_PC32 since it should be able to 349 // reach any 32 bit address. 350 case ELF::R_386_PLT32: 351 case ELF::R_386_PC32: { 352 uint32_t FinalAddress = 353 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 354 uint32_t RealOffset = Value + Addend - FinalAddress; 355 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 356 RealOffset; 357 break; 358 } 359 default: 360 // There are other relocation types, but it appears these are the 361 // only ones currently used by the LLVM ELF object writer 362 llvm_unreachable("Relocation type not implemented yet!"); 363 break; 364 } 365 } 366 367 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 368 uint64_t Offset, uint64_t Value, 369 uint32_t Type, int64_t Addend) { 370 uint32_t *TargetPtr = 371 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 372 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 373 // Data should use target endian. Code should always use little endian. 374 bool isBE = Arch == Triple::aarch64_be; 375 376 LLVM_DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 377 << format("%llx", Section.getAddressWithOffset(Offset)) 378 << " FinalAddress: 0x" << format("%llx", FinalAddress) 379 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 380 << format("%x", Type) << " Addend: 0x" 381 << format("%llx", Addend) << "\n"); 382 383 switch (Type) { 384 default: 385 llvm_unreachable("Relocation type not implemented yet!"); 386 break; 387 case ELF::R_AARCH64_ABS16: { 388 uint64_t Result = Value + Addend; 389 assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX); 390 write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU)); 391 break; 392 } 393 case ELF::R_AARCH64_ABS32: { 394 uint64_t Result = Value + Addend; 395 assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX); 396 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 397 break; 398 } 399 case ELF::R_AARCH64_ABS64: 400 write(isBE, TargetPtr, Value + Addend); 401 break; 402 case ELF::R_AARCH64_PREL32: { 403 uint64_t Result = Value + Addend - FinalAddress; 404 assert(static_cast<int64_t>(Result) >= INT32_MIN && 405 static_cast<int64_t>(Result) <= UINT32_MAX); 406 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 407 break; 408 } 409 case ELF::R_AARCH64_PREL64: 410 write(isBE, TargetPtr, Value + Addend - FinalAddress); 411 break; 412 case ELF::R_AARCH64_CALL26: // fallthrough 413 case ELF::R_AARCH64_JUMP26: { 414 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 415 // calculation. 416 uint64_t BranchImm = Value + Addend - FinalAddress; 417 418 // "Check that -2^27 <= result < 2^27". 419 assert(isInt<28>(BranchImm)); 420 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 421 break; 422 } 423 case ELF::R_AARCH64_MOVW_UABS_G3: 424 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 425 break; 426 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 427 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 428 break; 429 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 430 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 431 break; 432 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 433 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 434 break; 435 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 436 // Operation: Page(S+A) - Page(P) 437 uint64_t Result = 438 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 439 440 // Check that -2^32 <= X < 2^32 441 assert(isInt<33>(Result) && "overflow check failed for relocation"); 442 443 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 444 // from bits 32:12 of X. 445 write32AArch64Addr(TargetPtr, Result >> 12); 446 break; 447 } 448 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 449 // Operation: S + A 450 // Immediate goes in bits 21:10 of LD/ST instruction, taken 451 // from bits 11:0 of X 452 or32AArch64Imm(TargetPtr, Value + Addend); 453 break; 454 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 455 // Operation: S + A 456 // Immediate goes in bits 21:10 of LD/ST instruction, taken 457 // from bits 11:0 of X 458 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 459 break; 460 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 461 // Operation: S + A 462 // Immediate goes in bits 21:10 of LD/ST instruction, taken 463 // from bits 11:1 of X 464 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 465 break; 466 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 467 // Operation: S + A 468 // Immediate goes in bits 21:10 of LD/ST instruction, taken 469 // from bits 11:2 of X 470 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 471 break; 472 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 473 // Operation: S + A 474 // Immediate goes in bits 21:10 of LD/ST instruction, taken 475 // from bits 11:3 of X 476 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 477 break; 478 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 479 // Operation: S + A 480 // Immediate goes in bits 21:10 of LD/ST instruction, taken 481 // from bits 11:4 of X 482 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 483 break; 484 } 485 } 486 487 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 488 uint64_t Offset, uint32_t Value, 489 uint32_t Type, int32_t Addend) { 490 // TODO: Add Thumb relocations. 491 uint32_t *TargetPtr = 492 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 493 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 494 Value += Addend; 495 496 LLVM_DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 497 << Section.getAddressWithOffset(Offset) 498 << " FinalAddress: " << format("%p", FinalAddress) 499 << " Value: " << format("%x", Value) 500 << " Type: " << format("%x", Type) 501 << " Addend: " << format("%x", Addend) << "\n"); 502 503 switch (Type) { 504 default: 505 llvm_unreachable("Not implemented relocation type!"); 506 507 case ELF::R_ARM_NONE: 508 break; 509 // Write a 31bit signed offset 510 case ELF::R_ARM_PREL31: 511 support::ulittle32_t::ref{TargetPtr} = 512 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 513 ((Value - FinalAddress) & ~0x80000000); 514 break; 515 case ELF::R_ARM_TARGET1: 516 case ELF::R_ARM_ABS32: 517 support::ulittle32_t::ref{TargetPtr} = Value; 518 break; 519 // Write first 16 bit of 32 bit value to the mov instruction. 520 // Last 4 bit should be shifted. 521 case ELF::R_ARM_MOVW_ABS_NC: 522 case ELF::R_ARM_MOVT_ABS: 523 if (Type == ELF::R_ARM_MOVW_ABS_NC) 524 Value = Value & 0xFFFF; 525 else if (Type == ELF::R_ARM_MOVT_ABS) 526 Value = (Value >> 16) & 0xFFFF; 527 support::ulittle32_t::ref{TargetPtr} = 528 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 529 (((Value >> 12) & 0xF) << 16); 530 break; 531 // Write 24 bit relative value to the branch instruction. 532 case ELF::R_ARM_PC24: // Fall through. 533 case ELF::R_ARM_CALL: // Fall through. 534 case ELF::R_ARM_JUMP24: 535 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 536 RelValue = (RelValue & 0x03FFFFFC) >> 2; 537 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 538 support::ulittle32_t::ref{TargetPtr} = 539 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 540 break; 541 } 542 } 543 544 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 545 if (Arch == Triple::UnknownArch || 546 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 547 IsMipsO32ABI = false; 548 IsMipsN32ABI = false; 549 IsMipsN64ABI = false; 550 return; 551 } 552 if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) { 553 unsigned AbiVariant = E->getPlatformFlags(); 554 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 555 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 556 } 557 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); 558 } 559 560 // Return the .TOC. section and offset. 561 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 562 ObjSectionToIDMap &LocalSections, 563 RelocationValueRef &Rel) { 564 // Set a default SectionID in case we do not find a TOC section below. 565 // This may happen for references to TOC base base (sym@toc, .odp 566 // relocation) without a .toc directive. In this case just use the 567 // first section (which is usually the .odp) since the code won't 568 // reference the .toc base directly. 569 Rel.SymbolName = nullptr; 570 Rel.SectionID = 0; 571 572 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 573 // order. The TOC starts where the first of these sections starts. 574 for (auto &Section : Obj.sections()) { 575 Expected<StringRef> NameOrErr = Section.getName(); 576 if (!NameOrErr) 577 return NameOrErr.takeError(); 578 StringRef SectionName = *NameOrErr; 579 580 if (SectionName == ".got" 581 || SectionName == ".toc" 582 || SectionName == ".tocbss" 583 || SectionName == ".plt") { 584 if (auto SectionIDOrErr = 585 findOrEmitSection(Obj, Section, false, LocalSections)) 586 Rel.SectionID = *SectionIDOrErr; 587 else 588 return SectionIDOrErr.takeError(); 589 break; 590 } 591 } 592 593 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 594 // thus permitting a full 64 Kbytes segment. 595 Rel.Addend = 0x8000; 596 597 return Error::success(); 598 } 599 600 // Returns the sections and offset associated with the ODP entry referenced 601 // by Symbol. 602 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 603 ObjSectionToIDMap &LocalSections, 604 RelocationValueRef &Rel) { 605 // Get the ELF symbol value (st_value) to compare with Relocation offset in 606 // .opd entries 607 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 608 si != se; ++si) { 609 610 Expected<section_iterator> RelSecOrErr = si->getRelocatedSection(); 611 if (!RelSecOrErr) 612 report_fatal_error(toString(RelSecOrErr.takeError())); 613 614 section_iterator RelSecI = *RelSecOrErr; 615 if (RelSecI == Obj.section_end()) 616 continue; 617 618 Expected<StringRef> NameOrErr = RelSecI->getName(); 619 if (!NameOrErr) 620 return NameOrErr.takeError(); 621 StringRef RelSectionName = *NameOrErr; 622 623 if (RelSectionName != ".opd") 624 continue; 625 626 for (elf_relocation_iterator i = si->relocation_begin(), 627 e = si->relocation_end(); 628 i != e;) { 629 // The R_PPC64_ADDR64 relocation indicates the first field 630 // of a .opd entry 631 uint64_t TypeFunc = i->getType(); 632 if (TypeFunc != ELF::R_PPC64_ADDR64) { 633 ++i; 634 continue; 635 } 636 637 uint64_t TargetSymbolOffset = i->getOffset(); 638 symbol_iterator TargetSymbol = i->getSymbol(); 639 int64_t Addend; 640 if (auto AddendOrErr = i->getAddend()) 641 Addend = *AddendOrErr; 642 else 643 return AddendOrErr.takeError(); 644 645 ++i; 646 if (i == e) 647 break; 648 649 // Just check if following relocation is a R_PPC64_TOC 650 uint64_t TypeTOC = i->getType(); 651 if (TypeTOC != ELF::R_PPC64_TOC) 652 continue; 653 654 // Finally compares the Symbol value and the target symbol offset 655 // to check if this .opd entry refers to the symbol the relocation 656 // points to. 657 if (Rel.Addend != (int64_t)TargetSymbolOffset) 658 continue; 659 660 section_iterator TSI = Obj.section_end(); 661 if (auto TSIOrErr = TargetSymbol->getSection()) 662 TSI = *TSIOrErr; 663 else 664 return TSIOrErr.takeError(); 665 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 666 667 bool IsCode = TSI->isText(); 668 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 669 LocalSections)) 670 Rel.SectionID = *SectionIDOrErr; 671 else 672 return SectionIDOrErr.takeError(); 673 Rel.Addend = (intptr_t)Addend; 674 return Error::success(); 675 } 676 } 677 llvm_unreachable("Attempting to get address of ODP entry!"); 678 } 679 680 // Relocation masks following the #lo(value), #hi(value), #ha(value), 681 // #higher(value), #highera(value), #highest(value), and #highesta(value) 682 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 683 // document. 684 685 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 686 687 static inline uint16_t applyPPChi(uint64_t value) { 688 return (value >> 16) & 0xffff; 689 } 690 691 static inline uint16_t applyPPCha (uint64_t value) { 692 return ((value + 0x8000) >> 16) & 0xffff; 693 } 694 695 static inline uint16_t applyPPChigher(uint64_t value) { 696 return (value >> 32) & 0xffff; 697 } 698 699 static inline uint16_t applyPPChighera (uint64_t value) { 700 return ((value + 0x8000) >> 32) & 0xffff; 701 } 702 703 static inline uint16_t applyPPChighest(uint64_t value) { 704 return (value >> 48) & 0xffff; 705 } 706 707 static inline uint16_t applyPPChighesta (uint64_t value) { 708 return ((value + 0x8000) >> 48) & 0xffff; 709 } 710 711 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 712 uint64_t Offset, uint64_t Value, 713 uint32_t Type, int64_t Addend) { 714 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 715 switch (Type) { 716 default: 717 llvm_unreachable("Relocation type not implemented yet!"); 718 break; 719 case ELF::R_PPC_ADDR16_LO: 720 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 721 break; 722 case ELF::R_PPC_ADDR16_HI: 723 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 724 break; 725 case ELF::R_PPC_ADDR16_HA: 726 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 727 break; 728 } 729 } 730 731 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 732 uint64_t Offset, uint64_t Value, 733 uint32_t Type, int64_t Addend) { 734 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 735 switch (Type) { 736 default: 737 llvm_unreachable("Relocation type not implemented yet!"); 738 break; 739 case ELF::R_PPC64_ADDR16: 740 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 741 break; 742 case ELF::R_PPC64_ADDR16_DS: 743 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 744 break; 745 case ELF::R_PPC64_ADDR16_LO: 746 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 747 break; 748 case ELF::R_PPC64_ADDR16_LO_DS: 749 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 750 break; 751 case ELF::R_PPC64_ADDR16_HI: 752 case ELF::R_PPC64_ADDR16_HIGH: 753 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 754 break; 755 case ELF::R_PPC64_ADDR16_HA: 756 case ELF::R_PPC64_ADDR16_HIGHA: 757 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 758 break; 759 case ELF::R_PPC64_ADDR16_HIGHER: 760 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 761 break; 762 case ELF::R_PPC64_ADDR16_HIGHERA: 763 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 764 break; 765 case ELF::R_PPC64_ADDR16_HIGHEST: 766 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 767 break; 768 case ELF::R_PPC64_ADDR16_HIGHESTA: 769 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 770 break; 771 case ELF::R_PPC64_ADDR14: { 772 assert(((Value + Addend) & 3) == 0); 773 // Preserve the AA/LK bits in the branch instruction 774 uint8_t aalk = *(LocalAddress + 3); 775 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 776 } break; 777 case ELF::R_PPC64_REL16_LO: { 778 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 779 uint64_t Delta = Value - FinalAddress + Addend; 780 writeInt16BE(LocalAddress, applyPPClo(Delta)); 781 } break; 782 case ELF::R_PPC64_REL16_HI: { 783 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 784 uint64_t Delta = Value - FinalAddress + Addend; 785 writeInt16BE(LocalAddress, applyPPChi(Delta)); 786 } break; 787 case ELF::R_PPC64_REL16_HA: { 788 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 789 uint64_t Delta = Value - FinalAddress + Addend; 790 writeInt16BE(LocalAddress, applyPPCha(Delta)); 791 } break; 792 case ELF::R_PPC64_ADDR32: { 793 int64_t Result = static_cast<int64_t>(Value + Addend); 794 if (SignExtend64<32>(Result) != Result) 795 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 796 writeInt32BE(LocalAddress, Result); 797 } break; 798 case ELF::R_PPC64_REL24: { 799 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 800 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 801 if (SignExtend64<26>(delta) != delta) 802 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 803 // We preserve bits other than LI field, i.e. PO and AA/LK fields. 804 uint32_t Inst = readBytesUnaligned(LocalAddress, 4); 805 writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC)); 806 } break; 807 case ELF::R_PPC64_REL32: { 808 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 809 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 810 if (SignExtend64<32>(delta) != delta) 811 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 812 writeInt32BE(LocalAddress, delta); 813 } break; 814 case ELF::R_PPC64_REL64: { 815 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 816 uint64_t Delta = Value - FinalAddress + Addend; 817 writeInt64BE(LocalAddress, Delta); 818 } break; 819 case ELF::R_PPC64_ADDR64: 820 writeInt64BE(LocalAddress, Value + Addend); 821 break; 822 } 823 } 824 825 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 826 uint64_t Offset, uint64_t Value, 827 uint32_t Type, int64_t Addend) { 828 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 829 switch (Type) { 830 default: 831 llvm_unreachable("Relocation type not implemented yet!"); 832 break; 833 case ELF::R_390_PC16DBL: 834 case ELF::R_390_PLT16DBL: { 835 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 836 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 837 writeInt16BE(LocalAddress, Delta / 2); 838 break; 839 } 840 case ELF::R_390_PC32DBL: 841 case ELF::R_390_PLT32DBL: { 842 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 843 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 844 writeInt32BE(LocalAddress, Delta / 2); 845 break; 846 } 847 case ELF::R_390_PC16: { 848 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 849 assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); 850 writeInt16BE(LocalAddress, Delta); 851 break; 852 } 853 case ELF::R_390_PC32: { 854 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 855 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 856 writeInt32BE(LocalAddress, Delta); 857 break; 858 } 859 case ELF::R_390_PC64: { 860 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 861 writeInt64BE(LocalAddress, Delta); 862 break; 863 } 864 case ELF::R_390_8: 865 *LocalAddress = (uint8_t)(Value + Addend); 866 break; 867 case ELF::R_390_16: 868 writeInt16BE(LocalAddress, Value + Addend); 869 break; 870 case ELF::R_390_32: 871 writeInt32BE(LocalAddress, Value + Addend); 872 break; 873 case ELF::R_390_64: 874 writeInt64BE(LocalAddress, Value + Addend); 875 break; 876 } 877 } 878 879 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 880 uint64_t Offset, uint64_t Value, 881 uint32_t Type, int64_t Addend) { 882 bool isBE = Arch == Triple::bpfeb; 883 884 switch (Type) { 885 default: 886 llvm_unreachable("Relocation type not implemented yet!"); 887 break; 888 case ELF::R_BPF_NONE: 889 break; 890 case ELF::R_BPF_64_64: { 891 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 892 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 893 << format("%p\n", Section.getAddressWithOffset(Offset))); 894 break; 895 } 896 case ELF::R_BPF_64_32: { 897 Value += Addend; 898 assert(Value <= UINT32_MAX); 899 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 900 LLVM_DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 901 << format("%p\n", Section.getAddressWithOffset(Offset))); 902 break; 903 } 904 } 905 } 906 907 // The target location for the relocation is described by RE.SectionID and 908 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 909 // SectionEntry has three members describing its location. 910 // SectionEntry::Address is the address at which the section has been loaded 911 // into memory in the current (host) process. SectionEntry::LoadAddress is the 912 // address that the section will have in the target process. 913 // SectionEntry::ObjAddress is the address of the bits for this section in the 914 // original emitted object image (also in the current address space). 915 // 916 // Relocations will be applied as if the section were loaded at 917 // SectionEntry::LoadAddress, but they will be applied at an address based 918 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 919 // Target memory contents if they are required for value calculations. 920 // 921 // The Value parameter here is the load address of the symbol for the 922 // relocation to be applied. For relocations which refer to symbols in the 923 // current object Value will be the LoadAddress of the section in which 924 // the symbol resides (RE.Addend provides additional information about the 925 // symbol location). For external symbols, Value will be the address of the 926 // symbol in the target address space. 927 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 928 uint64_t Value) { 929 const SectionEntry &Section = Sections[RE.SectionID]; 930 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 931 RE.SymOffset, RE.SectionID); 932 } 933 934 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 935 uint64_t Offset, uint64_t Value, 936 uint32_t Type, int64_t Addend, 937 uint64_t SymOffset, SID SectionID) { 938 switch (Arch) { 939 case Triple::x86_64: 940 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 941 break; 942 case Triple::x86: 943 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 944 (uint32_t)(Addend & 0xffffffffL)); 945 break; 946 case Triple::aarch64: 947 case Triple::aarch64_be: 948 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 949 break; 950 case Triple::arm: // Fall through. 951 case Triple::armeb: 952 case Triple::thumb: 953 case Triple::thumbeb: 954 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 955 (uint32_t)(Addend & 0xffffffffL)); 956 break; 957 case Triple::ppc: 958 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 959 break; 960 case Triple::ppc64: // Fall through. 961 case Triple::ppc64le: 962 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 963 break; 964 case Triple::systemz: 965 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 966 break; 967 case Triple::bpfel: 968 case Triple::bpfeb: 969 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 970 break; 971 default: 972 llvm_unreachable("Unsupported CPU type!"); 973 } 974 } 975 976 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 977 return (void *)(Sections[SectionID].getObjAddress() + Offset); 978 } 979 980 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 981 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 982 if (Value.SymbolName) 983 addRelocationForSymbol(RE, Value.SymbolName); 984 else 985 addRelocationForSection(RE, Value.SectionID); 986 } 987 988 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 989 bool IsLocal) const { 990 switch (RelType) { 991 case ELF::R_MICROMIPS_GOT16: 992 if (IsLocal) 993 return ELF::R_MICROMIPS_LO16; 994 break; 995 case ELF::R_MICROMIPS_HI16: 996 return ELF::R_MICROMIPS_LO16; 997 case ELF::R_MIPS_GOT16: 998 if (IsLocal) 999 return ELF::R_MIPS_LO16; 1000 break; 1001 case ELF::R_MIPS_HI16: 1002 return ELF::R_MIPS_LO16; 1003 case ELF::R_MIPS_PCHI16: 1004 return ELF::R_MIPS_PCLO16; 1005 default: 1006 break; 1007 } 1008 return ELF::R_MIPS_NONE; 1009 } 1010 1011 // Sometimes we don't need to create thunk for a branch. 1012 // This typically happens when branch target is located 1013 // in the same object file. In such case target is either 1014 // a weak symbol or symbol in a different executable section. 1015 // This function checks if branch target is located in the 1016 // same object file and if distance between source and target 1017 // fits R_AARCH64_CALL26 relocation. If both conditions are 1018 // met, it emits direct jump to the target and returns true. 1019 // Otherwise false is returned and thunk is created. 1020 bool RuntimeDyldELF::resolveAArch64ShortBranch( 1021 unsigned SectionID, relocation_iterator RelI, 1022 const RelocationValueRef &Value) { 1023 uint64_t Address; 1024 if (Value.SymbolName) { 1025 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 1026 1027 // Don't create direct branch for external symbols. 1028 if (Loc == GlobalSymbolTable.end()) 1029 return false; 1030 1031 const auto &SymInfo = Loc->second; 1032 Address = 1033 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 1034 SymInfo.getOffset())); 1035 } else { 1036 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 1037 } 1038 uint64_t Offset = RelI->getOffset(); 1039 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 1040 1041 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 1042 // If distance between source and target is out of range then we should 1043 // create thunk. 1044 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 1045 return false; 1046 1047 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 1048 Value.Addend); 1049 1050 return true; 1051 } 1052 1053 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 1054 const RelocationValueRef &Value, 1055 relocation_iterator RelI, 1056 StubMap &Stubs) { 1057 1058 LLVM_DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1059 SectionEntry &Section = Sections[SectionID]; 1060 1061 uint64_t Offset = RelI->getOffset(); 1062 unsigned RelType = RelI->getType(); 1063 // Look for an existing stub. 1064 StubMap::const_iterator i = Stubs.find(Value); 1065 if (i != Stubs.end()) { 1066 resolveRelocation(Section, Offset, 1067 (uint64_t)Section.getAddressWithOffset(i->second), 1068 RelType, 0); 1069 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1070 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1071 // Create a new stub function. 1072 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1073 Stubs[Value] = Section.getStubOffset(); 1074 uint8_t *StubTargetAddr = createStubFunction( 1075 Section.getAddressWithOffset(Section.getStubOffset())); 1076 1077 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1078 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1079 RelocationEntry REmovk_g2(SectionID, 1080 StubTargetAddr - Section.getAddress() + 4, 1081 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1082 RelocationEntry REmovk_g1(SectionID, 1083 StubTargetAddr - Section.getAddress() + 8, 1084 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1085 RelocationEntry REmovk_g0(SectionID, 1086 StubTargetAddr - Section.getAddress() + 12, 1087 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1088 1089 if (Value.SymbolName) { 1090 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1091 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1092 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1093 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1094 } else { 1095 addRelocationForSection(REmovz_g3, Value.SectionID); 1096 addRelocationForSection(REmovk_g2, Value.SectionID); 1097 addRelocationForSection(REmovk_g1, Value.SectionID); 1098 addRelocationForSection(REmovk_g0, Value.SectionID); 1099 } 1100 resolveRelocation(Section, Offset, 1101 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1102 Section.getStubOffset())), 1103 RelType, 0); 1104 Section.advanceStubOffset(getMaxStubSize()); 1105 } 1106 } 1107 1108 Expected<relocation_iterator> 1109 RuntimeDyldELF::processRelocationRef( 1110 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1111 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1112 const auto &Obj = cast<ELFObjectFileBase>(O); 1113 uint64_t RelType = RelI->getType(); 1114 int64_t Addend = 0; 1115 if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend()) 1116 Addend = *AddendOrErr; 1117 else 1118 consumeError(AddendOrErr.takeError()); 1119 elf_symbol_iterator Symbol = RelI->getSymbol(); 1120 1121 // Obtain the symbol name which is referenced in the relocation 1122 StringRef TargetName; 1123 if (Symbol != Obj.symbol_end()) { 1124 if (auto TargetNameOrErr = Symbol->getName()) 1125 TargetName = *TargetNameOrErr; 1126 else 1127 return TargetNameOrErr.takeError(); 1128 } 1129 LLVM_DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1130 << " TargetName: " << TargetName << "\n"); 1131 RelocationValueRef Value; 1132 // First search for the symbol in the local symbol table 1133 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1134 1135 // Search for the symbol in the global symbol table 1136 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1137 if (Symbol != Obj.symbol_end()) { 1138 gsi = GlobalSymbolTable.find(TargetName.data()); 1139 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1140 if (!SymTypeOrErr) { 1141 std::string Buf; 1142 raw_string_ostream OS(Buf); 1143 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS); 1144 OS.flush(); 1145 report_fatal_error(Buf); 1146 } 1147 SymType = *SymTypeOrErr; 1148 } 1149 if (gsi != GlobalSymbolTable.end()) { 1150 const auto &SymInfo = gsi->second; 1151 Value.SectionID = SymInfo.getSectionID(); 1152 Value.Offset = SymInfo.getOffset(); 1153 Value.Addend = SymInfo.getOffset() + Addend; 1154 } else { 1155 switch (SymType) { 1156 case SymbolRef::ST_Debug: { 1157 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1158 // and can be changed by another developers. Maybe best way is add 1159 // a new symbol type ST_Section to SymbolRef and use it. 1160 auto SectionOrErr = Symbol->getSection(); 1161 if (!SectionOrErr) { 1162 std::string Buf; 1163 raw_string_ostream OS(Buf); 1164 logAllUnhandledErrors(SectionOrErr.takeError(), OS); 1165 OS.flush(); 1166 report_fatal_error(Buf); 1167 } 1168 section_iterator si = *SectionOrErr; 1169 if (si == Obj.section_end()) 1170 llvm_unreachable("Symbol section not found, bad object file format!"); 1171 LLVM_DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1172 bool isCode = si->isText(); 1173 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1174 ObjSectionToID)) 1175 Value.SectionID = *SectionIDOrErr; 1176 else 1177 return SectionIDOrErr.takeError(); 1178 Value.Addend = Addend; 1179 break; 1180 } 1181 case SymbolRef::ST_Data: 1182 case SymbolRef::ST_Function: 1183 case SymbolRef::ST_Unknown: { 1184 Value.SymbolName = TargetName.data(); 1185 Value.Addend = Addend; 1186 1187 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1188 // will manifest here as a NULL symbol name. 1189 // We can set this as a valid (but empty) symbol name, and rely 1190 // on addRelocationForSymbol to handle this. 1191 if (!Value.SymbolName) 1192 Value.SymbolName = ""; 1193 break; 1194 } 1195 default: 1196 llvm_unreachable("Unresolved symbol type!"); 1197 break; 1198 } 1199 } 1200 1201 uint64_t Offset = RelI->getOffset(); 1202 1203 LLVM_DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1204 << "\n"); 1205 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1206 if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { 1207 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1208 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1209 // Craete new GOT entry or find existing one. If GOT entry is 1210 // to be created, then we also emit ABS64 relocation for it. 1211 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1212 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1213 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1214 1215 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1216 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1217 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1218 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1219 } else { 1220 processSimpleRelocation(SectionID, Offset, RelType, Value); 1221 } 1222 } else if (Arch == Triple::arm) { 1223 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1224 RelType == ELF::R_ARM_JUMP24) { 1225 // This is an ARM branch relocation, need to use a stub function. 1226 LLVM_DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1227 SectionEntry &Section = Sections[SectionID]; 1228 1229 // Look for an existing stub. 1230 StubMap::const_iterator i = Stubs.find(Value); 1231 if (i != Stubs.end()) { 1232 resolveRelocation( 1233 Section, Offset, 1234 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1235 RelType, 0); 1236 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1237 } else { 1238 // Create a new stub function. 1239 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1240 Stubs[Value] = Section.getStubOffset(); 1241 uint8_t *StubTargetAddr = createStubFunction( 1242 Section.getAddressWithOffset(Section.getStubOffset())); 1243 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1244 ELF::R_ARM_ABS32, Value.Addend); 1245 if (Value.SymbolName) 1246 addRelocationForSymbol(RE, Value.SymbolName); 1247 else 1248 addRelocationForSection(RE, Value.SectionID); 1249 1250 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1251 Section.getAddressWithOffset( 1252 Section.getStubOffset())), 1253 RelType, 0); 1254 Section.advanceStubOffset(getMaxStubSize()); 1255 } 1256 } else { 1257 uint32_t *Placeholder = 1258 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1259 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1260 RelType == ELF::R_ARM_ABS32) { 1261 Value.Addend += *Placeholder; 1262 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1263 // See ELF for ARM documentation 1264 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1265 } 1266 processSimpleRelocation(SectionID, Offset, RelType, Value); 1267 } 1268 } else if (IsMipsO32ABI) { 1269 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1270 computePlaceholderAddress(SectionID, Offset)); 1271 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1272 if (RelType == ELF::R_MIPS_26) { 1273 // This is an Mips branch relocation, need to use a stub function. 1274 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1275 SectionEntry &Section = Sections[SectionID]; 1276 1277 // Extract the addend from the instruction. 1278 // We shift up by two since the Value will be down shifted again 1279 // when applying the relocation. 1280 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1281 1282 Value.Addend += Addend; 1283 1284 // Look up for existing stub. 1285 StubMap::const_iterator i = Stubs.find(Value); 1286 if (i != Stubs.end()) { 1287 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1288 addRelocationForSection(RE, SectionID); 1289 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1290 } else { 1291 // Create a new stub function. 1292 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1293 Stubs[Value] = Section.getStubOffset(); 1294 1295 unsigned AbiVariant = Obj.getPlatformFlags(); 1296 1297 uint8_t *StubTargetAddr = createStubFunction( 1298 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1299 1300 // Creating Hi and Lo relocations for the filled stub instructions. 1301 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1302 ELF::R_MIPS_HI16, Value.Addend); 1303 RelocationEntry RELo(SectionID, 1304 StubTargetAddr - Section.getAddress() + 4, 1305 ELF::R_MIPS_LO16, Value.Addend); 1306 1307 if (Value.SymbolName) { 1308 addRelocationForSymbol(REHi, Value.SymbolName); 1309 addRelocationForSymbol(RELo, Value.SymbolName); 1310 } else { 1311 addRelocationForSection(REHi, Value.SectionID); 1312 addRelocationForSection(RELo, Value.SectionID); 1313 } 1314 1315 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1316 addRelocationForSection(RE, SectionID); 1317 Section.advanceStubOffset(getMaxStubSize()); 1318 } 1319 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1320 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1321 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1322 PendingRelocs.push_back(std::make_pair(Value, RE)); 1323 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1324 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1325 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1326 const RelocationValueRef &MatchingValue = I->first; 1327 RelocationEntry &Reloc = I->second; 1328 if (MatchingValue == Value && 1329 RelType == getMatchingLoRelocation(Reloc.RelType) && 1330 SectionID == Reloc.SectionID) { 1331 Reloc.Addend += Addend; 1332 if (Value.SymbolName) 1333 addRelocationForSymbol(Reloc, Value.SymbolName); 1334 else 1335 addRelocationForSection(Reloc, Value.SectionID); 1336 I = PendingRelocs.erase(I); 1337 } else 1338 ++I; 1339 } 1340 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1341 if (Value.SymbolName) 1342 addRelocationForSymbol(RE, Value.SymbolName); 1343 else 1344 addRelocationForSection(RE, Value.SectionID); 1345 } else { 1346 if (RelType == ELF::R_MIPS_32) 1347 Value.Addend += Opcode; 1348 else if (RelType == ELF::R_MIPS_PC16) 1349 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1350 else if (RelType == ELF::R_MIPS_PC19_S2) 1351 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1352 else if (RelType == ELF::R_MIPS_PC21_S2) 1353 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1354 else if (RelType == ELF::R_MIPS_PC26_S2) 1355 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1356 processSimpleRelocation(SectionID, Offset, RelType, Value); 1357 } 1358 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1359 uint32_t r_type = RelType & 0xff; 1360 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1361 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1362 || r_type == ELF::R_MIPS_GOT_DISP) { 1363 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1364 if (i != GOTSymbolOffsets.end()) 1365 RE.SymOffset = i->second; 1366 else { 1367 RE.SymOffset = allocateGOTEntries(1); 1368 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1369 } 1370 if (Value.SymbolName) 1371 addRelocationForSymbol(RE, Value.SymbolName); 1372 else 1373 addRelocationForSection(RE, Value.SectionID); 1374 } else if (RelType == ELF::R_MIPS_26) { 1375 // This is an Mips branch relocation, need to use a stub function. 1376 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1377 SectionEntry &Section = Sections[SectionID]; 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 if (IsMipsN32ABI) { 1396 // Creating Hi and Lo relocations for the filled stub instructions. 1397 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1398 ELF::R_MIPS_HI16, Value.Addend); 1399 RelocationEntry RELo(SectionID, 1400 StubTargetAddr - Section.getAddress() + 4, 1401 ELF::R_MIPS_LO16, Value.Addend); 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 } else { 1410 // Creating Highest, Higher, Hi and Lo relocations for the filled stub 1411 // instructions. 1412 RelocationEntry REHighest(SectionID, 1413 StubTargetAddr - Section.getAddress(), 1414 ELF::R_MIPS_HIGHEST, Value.Addend); 1415 RelocationEntry REHigher(SectionID, 1416 StubTargetAddr - Section.getAddress() + 4, 1417 ELF::R_MIPS_HIGHER, Value.Addend); 1418 RelocationEntry REHi(SectionID, 1419 StubTargetAddr - Section.getAddress() + 12, 1420 ELF::R_MIPS_HI16, Value.Addend); 1421 RelocationEntry RELo(SectionID, 1422 StubTargetAddr - Section.getAddress() + 20, 1423 ELF::R_MIPS_LO16, Value.Addend); 1424 if (Value.SymbolName) { 1425 addRelocationForSymbol(REHighest, Value.SymbolName); 1426 addRelocationForSymbol(REHigher, Value.SymbolName); 1427 addRelocationForSymbol(REHi, Value.SymbolName); 1428 addRelocationForSymbol(RELo, Value.SymbolName); 1429 } else { 1430 addRelocationForSection(REHighest, Value.SectionID); 1431 addRelocationForSection(REHigher, Value.SectionID); 1432 addRelocationForSection(REHi, Value.SectionID); 1433 addRelocationForSection(RELo, Value.SectionID); 1434 } 1435 } 1436 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1437 addRelocationForSection(RE, SectionID); 1438 Section.advanceStubOffset(getMaxStubSize()); 1439 } 1440 } else { 1441 processSimpleRelocation(SectionID, Offset, RelType, Value); 1442 } 1443 1444 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1445 if (RelType == ELF::R_PPC64_REL24) { 1446 // Determine ABI variant in use for this object. 1447 unsigned AbiVariant = Obj.getPlatformFlags(); 1448 AbiVariant &= ELF::EF_PPC64_ABI; 1449 // A PPC branch relocation will need a stub function if the target is 1450 // an external symbol (either Value.SymbolName is set, or SymType is 1451 // Symbol::ST_Unknown) or if the target address is not within the 1452 // signed 24-bits branch address. 1453 SectionEntry &Section = Sections[SectionID]; 1454 uint8_t *Target = Section.getAddressWithOffset(Offset); 1455 bool RangeOverflow = false; 1456 bool IsExtern = Value.SymbolName || SymType == SymbolRef::ST_Unknown; 1457 if (!IsExtern) { 1458 if (AbiVariant != 2) { 1459 // In the ELFv1 ABI, a function call may point to the .opd entry, 1460 // so the final symbol value is calculated based on the relocation 1461 // values in the .opd section. 1462 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1463 return std::move(Err); 1464 } else { 1465 // In the ELFv2 ABI, a function symbol may provide a local entry 1466 // point, which must be used for direct calls. 1467 if (Value.SectionID == SectionID){ 1468 uint8_t SymOther = Symbol->getOther(); 1469 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1470 } 1471 } 1472 uint8_t *RelocTarget = 1473 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1474 int64_t delta = static_cast<int64_t>(Target - RelocTarget); 1475 // If it is within 26-bits branch range, just set the branch target 1476 if (SignExtend64<26>(delta) != delta) { 1477 RangeOverflow = true; 1478 } else if ((AbiVariant != 2) || 1479 (AbiVariant == 2 && Value.SectionID == SectionID)) { 1480 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1481 addRelocationForSection(RE, Value.SectionID); 1482 } 1483 } 1484 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID) || 1485 RangeOverflow) { 1486 // It is an external symbol (either Value.SymbolName is set, or 1487 // SymType is SymbolRef::ST_Unknown) or out of range. 1488 StubMap::const_iterator i = Stubs.find(Value); 1489 if (i != Stubs.end()) { 1490 // Symbol function stub already created, just relocate to it 1491 resolveRelocation(Section, Offset, 1492 reinterpret_cast<uint64_t>( 1493 Section.getAddressWithOffset(i->second)), 1494 RelType, 0); 1495 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1496 } else { 1497 // Create a new stub function. 1498 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1499 Stubs[Value] = Section.getStubOffset(); 1500 uint8_t *StubTargetAddr = createStubFunction( 1501 Section.getAddressWithOffset(Section.getStubOffset()), 1502 AbiVariant); 1503 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1504 ELF::R_PPC64_ADDR64, Value.Addend); 1505 1506 // Generates the 64-bits address loads as exemplified in section 1507 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1508 // apply to the low part of the instructions, so we have to update 1509 // the offset according to the target endianness. 1510 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1511 if (!IsTargetLittleEndian) 1512 StubRelocOffset += 2; 1513 1514 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1515 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1516 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1517 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1518 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1519 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1520 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1521 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1522 1523 if (Value.SymbolName) { 1524 addRelocationForSymbol(REhst, Value.SymbolName); 1525 addRelocationForSymbol(REhr, Value.SymbolName); 1526 addRelocationForSymbol(REh, Value.SymbolName); 1527 addRelocationForSymbol(REl, Value.SymbolName); 1528 } else { 1529 addRelocationForSection(REhst, Value.SectionID); 1530 addRelocationForSection(REhr, Value.SectionID); 1531 addRelocationForSection(REh, Value.SectionID); 1532 addRelocationForSection(REl, Value.SectionID); 1533 } 1534 1535 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1536 Section.getAddressWithOffset( 1537 Section.getStubOffset())), 1538 RelType, 0); 1539 Section.advanceStubOffset(getMaxStubSize()); 1540 } 1541 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID)) { 1542 // Restore the TOC for external calls 1543 if (AbiVariant == 2) 1544 writeInt32BE(Target + 4, 0xE8410018); // ld r2,24(r1) 1545 else 1546 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1547 } 1548 } 1549 } else if (RelType == ELF::R_PPC64_TOC16 || 1550 RelType == ELF::R_PPC64_TOC16_DS || 1551 RelType == ELF::R_PPC64_TOC16_LO || 1552 RelType == ELF::R_PPC64_TOC16_LO_DS || 1553 RelType == ELF::R_PPC64_TOC16_HI || 1554 RelType == ELF::R_PPC64_TOC16_HA) { 1555 // These relocations are supposed to subtract the TOC address from 1556 // the final value. This does not fit cleanly into the RuntimeDyld 1557 // scheme, since there may be *two* sections involved in determining 1558 // the relocation value (the section of the symbol referred to by the 1559 // relocation, and the TOC section associated with the current module). 1560 // 1561 // Fortunately, these relocations are currently only ever generated 1562 // referring to symbols that themselves reside in the TOC, which means 1563 // that the two sections are actually the same. Thus they cancel out 1564 // and we can immediately resolve the relocation right now. 1565 switch (RelType) { 1566 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1567 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1568 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1569 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1570 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1571 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1572 default: llvm_unreachable("Wrong relocation type."); 1573 } 1574 1575 RelocationValueRef TOCValue; 1576 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1577 return std::move(Err); 1578 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1579 llvm_unreachable("Unsupported TOC relocation."); 1580 Value.Addend -= TOCValue.Addend; 1581 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1582 } else { 1583 // There are two ways to refer to the TOC address directly: either 1584 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1585 // ignored), or via any relocation that refers to the magic ".TOC." 1586 // symbols (in which case the addend is respected). 1587 if (RelType == ELF::R_PPC64_TOC) { 1588 RelType = ELF::R_PPC64_ADDR64; 1589 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1590 return std::move(Err); 1591 } else if (TargetName == ".TOC.") { 1592 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1593 return std::move(Err); 1594 Value.Addend += Addend; 1595 } 1596 1597 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1598 1599 if (Value.SymbolName) 1600 addRelocationForSymbol(RE, Value.SymbolName); 1601 else 1602 addRelocationForSection(RE, Value.SectionID); 1603 } 1604 } else if (Arch == Triple::systemz && 1605 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1606 // Create function stubs for both PLT and GOT references, regardless of 1607 // whether the GOT reference is to data or code. The stub contains the 1608 // full address of the symbol, as needed by GOT references, and the 1609 // executable part only adds an overhead of 8 bytes. 1610 // 1611 // We could try to conserve space by allocating the code and data 1612 // parts of the stub separately. However, as things stand, we allocate 1613 // a stub for every relocation, so using a GOT in JIT code should be 1614 // no less space efficient than using an explicit constant pool. 1615 LLVM_DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1616 SectionEntry &Section = Sections[SectionID]; 1617 1618 // Look for an existing stub. 1619 StubMap::const_iterator i = Stubs.find(Value); 1620 uintptr_t StubAddress; 1621 if (i != Stubs.end()) { 1622 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1623 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1624 } else { 1625 // Create a new stub function. 1626 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1627 1628 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1629 uintptr_t StubAlignment = getStubAlignment(); 1630 StubAddress = 1631 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1632 -StubAlignment; 1633 unsigned StubOffset = StubAddress - BaseAddress; 1634 1635 Stubs[Value] = StubOffset; 1636 createStubFunction((uint8_t *)StubAddress); 1637 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1638 Value.Offset); 1639 if (Value.SymbolName) 1640 addRelocationForSymbol(RE, Value.SymbolName); 1641 else 1642 addRelocationForSection(RE, Value.SectionID); 1643 Section.advanceStubOffset(getMaxStubSize()); 1644 } 1645 1646 if (RelType == ELF::R_390_GOTENT) 1647 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1648 Addend); 1649 else 1650 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1651 } else if (Arch == Triple::x86_64) { 1652 if (RelType == ELF::R_X86_64_PLT32) { 1653 // The way the PLT relocations normally work is that the linker allocates 1654 // the 1655 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1656 // entry will then jump to an address provided by the GOT. On first call, 1657 // the 1658 // GOT address will point back into PLT code that resolves the symbol. After 1659 // the first call, the GOT entry points to the actual function. 1660 // 1661 // For local functions we're ignoring all of that here and just replacing 1662 // the PLT32 relocation type with PC32, which will translate the relocation 1663 // into a PC-relative call directly to the function. For external symbols we 1664 // can't be sure the function will be within 2^32 bytes of the call site, so 1665 // we need to create a stub, which calls into the GOT. This case is 1666 // equivalent to the usual PLT implementation except that we use the stub 1667 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1668 // rather than allocating a PLT section. 1669 if (Value.SymbolName) { 1670 // This is a call to an external function. 1671 // Look for an existing stub. 1672 SectionEntry &Section = Sections[SectionID]; 1673 StubMap::const_iterator i = Stubs.find(Value); 1674 uintptr_t StubAddress; 1675 if (i != Stubs.end()) { 1676 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1677 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1678 } else { 1679 // Create a new stub function (equivalent to a PLT entry). 1680 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1681 1682 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1683 uintptr_t StubAlignment = getStubAlignment(); 1684 StubAddress = 1685 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1686 -StubAlignment; 1687 unsigned StubOffset = StubAddress - BaseAddress; 1688 Stubs[Value] = StubOffset; 1689 createStubFunction((uint8_t *)StubAddress); 1690 1691 // Bump our stub offset counter 1692 Section.advanceStubOffset(getMaxStubSize()); 1693 1694 // Allocate a GOT Entry 1695 uint64_t GOTOffset = allocateGOTEntries(1); 1696 1697 // The load of the GOT address has an addend of -4 1698 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1699 ELF::R_X86_64_PC32); 1700 1701 // Fill in the value of the symbol we're targeting into the GOT 1702 addRelocationForSymbol( 1703 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1704 Value.SymbolName); 1705 } 1706 1707 // Make the target call a call into the stub table. 1708 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1709 Addend); 1710 } else { 1711 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1712 Value.Offset); 1713 addRelocationForSection(RE, Value.SectionID); 1714 } 1715 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1716 RelType == ELF::R_X86_64_GOTPCRELX || 1717 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1718 uint64_t GOTOffset = allocateGOTEntries(1); 1719 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1720 ELF::R_X86_64_PC32); 1721 1722 // Fill in the value of the symbol we're targeting into the GOT 1723 RelocationEntry RE = 1724 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1725 if (Value.SymbolName) 1726 addRelocationForSymbol(RE, Value.SymbolName); 1727 else 1728 addRelocationForSection(RE, Value.SectionID); 1729 } else if (RelType == ELF::R_X86_64_GOT64) { 1730 // Fill in a 64-bit GOT offset. 1731 uint64_t GOTOffset = allocateGOTEntries(1); 1732 resolveRelocation(Sections[SectionID], Offset, GOTOffset, 1733 ELF::R_X86_64_64, 0); 1734 1735 // Fill in the value of the symbol we're targeting into the GOT 1736 RelocationEntry RE = 1737 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1738 if (Value.SymbolName) 1739 addRelocationForSymbol(RE, Value.SymbolName); 1740 else 1741 addRelocationForSection(RE, Value.SectionID); 1742 } else if (RelType == ELF::R_X86_64_GOTPC64) { 1743 // Materialize the address of the base of the GOT relative to the PC. 1744 // This doesn't create a GOT entry, but it does mean we need a GOT 1745 // section. 1746 (void)allocateGOTEntries(0); 1747 resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC64); 1748 } else if (RelType == ELF::R_X86_64_GOTOFF64) { 1749 // GOTOFF relocations ultimately require a section difference relocation. 1750 (void)allocateGOTEntries(0); 1751 processSimpleRelocation(SectionID, Offset, RelType, Value); 1752 } else if (RelType == ELF::R_X86_64_PC32) { 1753 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1754 processSimpleRelocation(SectionID, Offset, RelType, Value); 1755 } else if (RelType == ELF::R_X86_64_PC64) { 1756 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1757 processSimpleRelocation(SectionID, Offset, RelType, Value); 1758 } else { 1759 processSimpleRelocation(SectionID, Offset, RelType, Value); 1760 } 1761 } else { 1762 if (Arch == Triple::x86) { 1763 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1764 } 1765 processSimpleRelocation(SectionID, Offset, RelType, Value); 1766 } 1767 return ++RelI; 1768 } 1769 1770 size_t RuntimeDyldELF::getGOTEntrySize() { 1771 // We don't use the GOT in all of these cases, but it's essentially free 1772 // to put them all here. 1773 size_t Result = 0; 1774 switch (Arch) { 1775 case Triple::x86_64: 1776 case Triple::aarch64: 1777 case Triple::aarch64_be: 1778 case Triple::ppc64: 1779 case Triple::ppc64le: 1780 case Triple::systemz: 1781 Result = sizeof(uint64_t); 1782 break; 1783 case Triple::x86: 1784 case Triple::arm: 1785 case Triple::thumb: 1786 Result = sizeof(uint32_t); 1787 break; 1788 case Triple::mips: 1789 case Triple::mipsel: 1790 case Triple::mips64: 1791 case Triple::mips64el: 1792 if (IsMipsO32ABI || IsMipsN32ABI) 1793 Result = sizeof(uint32_t); 1794 else if (IsMipsN64ABI) 1795 Result = sizeof(uint64_t); 1796 else 1797 llvm_unreachable("Mips ABI not handled"); 1798 break; 1799 default: 1800 llvm_unreachable("Unsupported CPU type!"); 1801 } 1802 return Result; 1803 } 1804 1805 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 1806 if (GOTSectionID == 0) { 1807 GOTSectionID = Sections.size(); 1808 // Reserve a section id. We'll allocate the section later 1809 // once we know the total size 1810 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1811 } 1812 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1813 CurrentGOTIndex += no; 1814 return StartOffset; 1815 } 1816 1817 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 1818 unsigned GOTRelType) { 1819 auto E = GOTOffsetMap.insert({Value, 0}); 1820 if (E.second) { 1821 uint64_t GOTOffset = allocateGOTEntries(1); 1822 1823 // Create relocation for newly created GOT entry 1824 RelocationEntry RE = 1825 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 1826 if (Value.SymbolName) 1827 addRelocationForSymbol(RE, Value.SymbolName); 1828 else 1829 addRelocationForSection(RE, Value.SectionID); 1830 1831 E.first->second = GOTOffset; 1832 } 1833 1834 return E.first->second; 1835 } 1836 1837 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 1838 uint64_t Offset, 1839 uint64_t GOTOffset, 1840 uint32_t Type) { 1841 // Fill in the relative address of the GOT Entry into the stub 1842 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 1843 addRelocationForSection(GOTRE, GOTSectionID); 1844 } 1845 1846 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 1847 uint64_t SymbolOffset, 1848 uint32_t Type) { 1849 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1850 } 1851 1852 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1853 ObjSectionToIDMap &SectionMap) { 1854 if (IsMipsO32ABI) 1855 if (!PendingRelocs.empty()) 1856 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1857 1858 // If necessary, allocate the global offset table 1859 if (GOTSectionID != 0) { 1860 // Allocate memory for the section 1861 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1862 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1863 GOTSectionID, ".got", false); 1864 if (!Addr) 1865 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1866 1867 Sections[GOTSectionID] = 1868 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1869 1870 // For now, initialize all GOT entries to zero. We'll fill them in as 1871 // needed when GOT-based relocations are applied. 1872 memset(Addr, 0, TotalSize); 1873 if (IsMipsN32ABI || IsMipsN64ABI) { 1874 // To correctly resolve Mips GOT relocations, we need a mapping from 1875 // object's sections to GOTs. 1876 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1877 SI != SE; ++SI) { 1878 if (SI->relocation_begin() != SI->relocation_end()) { 1879 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection(); 1880 if (!RelSecOrErr) 1881 return make_error<RuntimeDyldError>( 1882 toString(RelSecOrErr.takeError())); 1883 1884 section_iterator RelocatedSection = *RelSecOrErr; 1885 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1886 assert (i != SectionMap.end()); 1887 SectionToGOTMap[i->second] = GOTSectionID; 1888 } 1889 } 1890 GOTSymbolOffsets.clear(); 1891 } 1892 } 1893 1894 // Look for and record the EH frame section. 1895 ObjSectionToIDMap::iterator i, e; 1896 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1897 const SectionRef &Section = i->first; 1898 1899 StringRef Name; 1900 Expected<StringRef> NameOrErr = Section.getName(); 1901 if (NameOrErr) 1902 Name = *NameOrErr; 1903 else 1904 consumeError(NameOrErr.takeError()); 1905 1906 if (Name == ".eh_frame") { 1907 UnregisteredEHFrameSections.push_back(i->second); 1908 break; 1909 } 1910 } 1911 1912 GOTSectionID = 0; 1913 CurrentGOTIndex = 0; 1914 1915 return Error::success(); 1916 } 1917 1918 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1919 return Obj.isELF(); 1920 } 1921 1922 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 1923 unsigned RelTy = R.getType(); 1924 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 1925 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 1926 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 1927 1928 if (Arch == Triple::x86_64) 1929 return RelTy == ELF::R_X86_64_GOTPCREL || 1930 RelTy == ELF::R_X86_64_GOTPCRELX || 1931 RelTy == ELF::R_X86_64_GOT64 || 1932 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 1933 return false; 1934 } 1935 1936 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1937 if (Arch != Triple::x86_64) 1938 return true; // Conservative answer 1939 1940 switch (R.getType()) { 1941 default: 1942 return true; // Conservative answer 1943 1944 1945 case ELF::R_X86_64_GOTPCREL: 1946 case ELF::R_X86_64_GOTPCRELX: 1947 case ELF::R_X86_64_REX_GOTPCRELX: 1948 case ELF::R_X86_64_GOTPC64: 1949 case ELF::R_X86_64_GOT64: 1950 case ELF::R_X86_64_GOTOFF64: 1951 case ELF::R_X86_64_PC32: 1952 case ELF::R_X86_64_PC64: 1953 case ELF::R_X86_64_64: 1954 // We know that these reloation types won't need a stub function. This list 1955 // can be extended as needed. 1956 return false; 1957 } 1958 } 1959 1960 } // namespace llvm 1961