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 report_fatal_error("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 report_fatal_error("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 report_fatal_error("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_PLT32: { 403 uint64_t Result = Value + Addend - FinalAddress; 404 assert(static_cast<int64_t>(Result) >= INT32_MIN && 405 static_cast<int64_t>(Result) <= INT32_MAX); 406 write(isBE, TargetPtr, static_cast<uint32_t>(Result)); 407 break; 408 } 409 case ELF::R_AARCH64_PREL32: { 410 uint64_t Result = Value + Addend - FinalAddress; 411 assert(static_cast<int64_t>(Result) >= INT32_MIN && 412 static_cast<int64_t>(Result) <= UINT32_MAX); 413 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 414 break; 415 } 416 case ELF::R_AARCH64_PREL64: 417 write(isBE, TargetPtr, Value + Addend - FinalAddress); 418 break; 419 case ELF::R_AARCH64_CALL26: // fallthrough 420 case ELF::R_AARCH64_JUMP26: { 421 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 422 // calculation. 423 uint64_t BranchImm = Value + Addend - FinalAddress; 424 425 // "Check that -2^27 <= result < 2^27". 426 assert(isInt<28>(BranchImm)); 427 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 428 break; 429 } 430 case ELF::R_AARCH64_MOVW_UABS_G3: 431 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 432 break; 433 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 434 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 435 break; 436 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 437 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 438 break; 439 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 440 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 441 break; 442 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 443 // Operation: Page(S+A) - Page(P) 444 uint64_t Result = 445 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 446 447 // Check that -2^32 <= X < 2^32 448 assert(isInt<33>(Result) && "overflow check failed for relocation"); 449 450 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 451 // from bits 32:12 of X. 452 write32AArch64Addr(TargetPtr, Result >> 12); 453 break; 454 } 455 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 456 // Operation: S + A 457 // Immediate goes in bits 21:10 of LD/ST instruction, taken 458 // from bits 11:0 of X 459 or32AArch64Imm(TargetPtr, Value + Addend); 460 break; 461 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 462 // Operation: S + A 463 // Immediate goes in bits 21:10 of LD/ST instruction, taken 464 // from bits 11:0 of X 465 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 466 break; 467 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 468 // Operation: S + A 469 // Immediate goes in bits 21:10 of LD/ST instruction, taken 470 // from bits 11:1 of X 471 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 472 break; 473 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 474 // Operation: S + A 475 // Immediate goes in bits 21:10 of LD/ST instruction, taken 476 // from bits 11:2 of X 477 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 478 break; 479 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 480 // Operation: S + A 481 // Immediate goes in bits 21:10 of LD/ST instruction, taken 482 // from bits 11:3 of X 483 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 484 break; 485 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 486 // Operation: S + A 487 // Immediate goes in bits 21:10 of LD/ST instruction, taken 488 // from bits 11:4 of X 489 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 490 break; 491 } 492 } 493 494 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 495 uint64_t Offset, uint32_t Value, 496 uint32_t Type, int32_t Addend) { 497 // TODO: Add Thumb relocations. 498 uint32_t *TargetPtr = 499 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 500 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 501 Value += Addend; 502 503 LLVM_DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 504 << Section.getAddressWithOffset(Offset) 505 << " FinalAddress: " << format("%p", FinalAddress) 506 << " Value: " << format("%x", Value) 507 << " Type: " << format("%x", Type) 508 << " Addend: " << format("%x", Addend) << "\n"); 509 510 switch (Type) { 511 default: 512 llvm_unreachable("Not implemented relocation type!"); 513 514 case ELF::R_ARM_NONE: 515 break; 516 // Write a 31bit signed offset 517 case ELF::R_ARM_PREL31: 518 support::ulittle32_t::ref{TargetPtr} = 519 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 520 ((Value - FinalAddress) & ~0x80000000); 521 break; 522 case ELF::R_ARM_TARGET1: 523 case ELF::R_ARM_ABS32: 524 support::ulittle32_t::ref{TargetPtr} = Value; 525 break; 526 // Write first 16 bit of 32 bit value to the mov instruction. 527 // Last 4 bit should be shifted. 528 case ELF::R_ARM_MOVW_ABS_NC: 529 case ELF::R_ARM_MOVT_ABS: 530 if (Type == ELF::R_ARM_MOVW_ABS_NC) 531 Value = Value & 0xFFFF; 532 else if (Type == ELF::R_ARM_MOVT_ABS) 533 Value = (Value >> 16) & 0xFFFF; 534 support::ulittle32_t::ref{TargetPtr} = 535 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 536 (((Value >> 12) & 0xF) << 16); 537 break; 538 // Write 24 bit relative value to the branch instruction. 539 case ELF::R_ARM_PC24: // Fall through. 540 case ELF::R_ARM_CALL: // Fall through. 541 case ELF::R_ARM_JUMP24: 542 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 543 RelValue = (RelValue & 0x03FFFFFC) >> 2; 544 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 545 support::ulittle32_t::ref{TargetPtr} = 546 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 547 break; 548 } 549 } 550 551 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 552 if (Arch == Triple::UnknownArch || 553 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 554 IsMipsO32ABI = false; 555 IsMipsN32ABI = false; 556 IsMipsN64ABI = false; 557 return; 558 } 559 if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) { 560 unsigned AbiVariant = E->getPlatformFlags(); 561 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 562 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 563 } 564 IsMipsN64ABI = Obj.getFileFormatName().equals("elf64-mips"); 565 } 566 567 // Return the .TOC. section and offset. 568 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 569 ObjSectionToIDMap &LocalSections, 570 RelocationValueRef &Rel) { 571 // Set a default SectionID in case we do not find a TOC section below. 572 // This may happen for references to TOC base base (sym@toc, .odp 573 // relocation) without a .toc directive. In this case just use the 574 // first section (which is usually the .odp) since the code won't 575 // reference the .toc base directly. 576 Rel.SymbolName = nullptr; 577 Rel.SectionID = 0; 578 579 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 580 // order. The TOC starts where the first of these sections starts. 581 for (auto &Section : Obj.sections()) { 582 Expected<StringRef> NameOrErr = Section.getName(); 583 if (!NameOrErr) 584 return NameOrErr.takeError(); 585 StringRef SectionName = *NameOrErr; 586 587 if (SectionName == ".got" 588 || SectionName == ".toc" 589 || SectionName == ".tocbss" 590 || SectionName == ".plt") { 591 if (auto SectionIDOrErr = 592 findOrEmitSection(Obj, Section, false, LocalSections)) 593 Rel.SectionID = *SectionIDOrErr; 594 else 595 return SectionIDOrErr.takeError(); 596 break; 597 } 598 } 599 600 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 601 // thus permitting a full 64 Kbytes segment. 602 Rel.Addend = 0x8000; 603 604 return Error::success(); 605 } 606 607 // Returns the sections and offset associated with the ODP entry referenced 608 // by Symbol. 609 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 610 ObjSectionToIDMap &LocalSections, 611 RelocationValueRef &Rel) { 612 // Get the ELF symbol value (st_value) to compare with Relocation offset in 613 // .opd entries 614 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 615 si != se; ++si) { 616 617 Expected<section_iterator> RelSecOrErr = si->getRelocatedSection(); 618 if (!RelSecOrErr) 619 report_fatal_error(toString(RelSecOrErr.takeError())); 620 621 section_iterator RelSecI = *RelSecOrErr; 622 if (RelSecI == Obj.section_end()) 623 continue; 624 625 Expected<StringRef> NameOrErr = RelSecI->getName(); 626 if (!NameOrErr) 627 return NameOrErr.takeError(); 628 StringRef RelSectionName = *NameOrErr; 629 630 if (RelSectionName != ".opd") 631 continue; 632 633 for (elf_relocation_iterator i = si->relocation_begin(), 634 e = si->relocation_end(); 635 i != e;) { 636 // The R_PPC64_ADDR64 relocation indicates the first field 637 // of a .opd entry 638 uint64_t TypeFunc = i->getType(); 639 if (TypeFunc != ELF::R_PPC64_ADDR64) { 640 ++i; 641 continue; 642 } 643 644 uint64_t TargetSymbolOffset = i->getOffset(); 645 symbol_iterator TargetSymbol = i->getSymbol(); 646 int64_t Addend; 647 if (auto AddendOrErr = i->getAddend()) 648 Addend = *AddendOrErr; 649 else 650 return AddendOrErr.takeError(); 651 652 ++i; 653 if (i == e) 654 break; 655 656 // Just check if following relocation is a R_PPC64_TOC 657 uint64_t TypeTOC = i->getType(); 658 if (TypeTOC != ELF::R_PPC64_TOC) 659 continue; 660 661 // Finally compares the Symbol value and the target symbol offset 662 // to check if this .opd entry refers to the symbol the relocation 663 // points to. 664 if (Rel.Addend != (int64_t)TargetSymbolOffset) 665 continue; 666 667 section_iterator TSI = Obj.section_end(); 668 if (auto TSIOrErr = TargetSymbol->getSection()) 669 TSI = *TSIOrErr; 670 else 671 return TSIOrErr.takeError(); 672 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 673 674 bool IsCode = TSI->isText(); 675 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 676 LocalSections)) 677 Rel.SectionID = *SectionIDOrErr; 678 else 679 return SectionIDOrErr.takeError(); 680 Rel.Addend = (intptr_t)Addend; 681 return Error::success(); 682 } 683 } 684 llvm_unreachable("Attempting to get address of ODP entry!"); 685 } 686 687 // Relocation masks following the #lo(value), #hi(value), #ha(value), 688 // #higher(value), #highera(value), #highest(value), and #highesta(value) 689 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 690 // document. 691 692 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 693 694 static inline uint16_t applyPPChi(uint64_t value) { 695 return (value >> 16) & 0xffff; 696 } 697 698 static inline uint16_t applyPPCha (uint64_t value) { 699 return ((value + 0x8000) >> 16) & 0xffff; 700 } 701 702 static inline uint16_t applyPPChigher(uint64_t value) { 703 return (value >> 32) & 0xffff; 704 } 705 706 static inline uint16_t applyPPChighera (uint64_t value) { 707 return ((value + 0x8000) >> 32) & 0xffff; 708 } 709 710 static inline uint16_t applyPPChighest(uint64_t value) { 711 return (value >> 48) & 0xffff; 712 } 713 714 static inline uint16_t applyPPChighesta (uint64_t value) { 715 return ((value + 0x8000) >> 48) & 0xffff; 716 } 717 718 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 719 uint64_t Offset, uint64_t Value, 720 uint32_t Type, int64_t Addend) { 721 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 722 switch (Type) { 723 default: 724 report_fatal_error("Relocation type not implemented yet!"); 725 break; 726 case ELF::R_PPC_ADDR16_LO: 727 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 728 break; 729 case ELF::R_PPC_ADDR16_HI: 730 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 731 break; 732 case ELF::R_PPC_ADDR16_HA: 733 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 734 break; 735 } 736 } 737 738 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 739 uint64_t Offset, uint64_t Value, 740 uint32_t Type, int64_t Addend) { 741 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 742 switch (Type) { 743 default: 744 report_fatal_error("Relocation type not implemented yet!"); 745 break; 746 case ELF::R_PPC64_ADDR16: 747 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 748 break; 749 case ELF::R_PPC64_ADDR16_DS: 750 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 751 break; 752 case ELF::R_PPC64_ADDR16_LO: 753 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 754 break; 755 case ELF::R_PPC64_ADDR16_LO_DS: 756 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 757 break; 758 case ELF::R_PPC64_ADDR16_HI: 759 case ELF::R_PPC64_ADDR16_HIGH: 760 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 761 break; 762 case ELF::R_PPC64_ADDR16_HA: 763 case ELF::R_PPC64_ADDR16_HIGHA: 764 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 765 break; 766 case ELF::R_PPC64_ADDR16_HIGHER: 767 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 768 break; 769 case ELF::R_PPC64_ADDR16_HIGHERA: 770 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 771 break; 772 case ELF::R_PPC64_ADDR16_HIGHEST: 773 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 774 break; 775 case ELF::R_PPC64_ADDR16_HIGHESTA: 776 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 777 break; 778 case ELF::R_PPC64_ADDR14: { 779 assert(((Value + Addend) & 3) == 0); 780 // Preserve the AA/LK bits in the branch instruction 781 uint8_t aalk = *(LocalAddress + 3); 782 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 783 } break; 784 case ELF::R_PPC64_REL16_LO: { 785 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 786 uint64_t Delta = Value - FinalAddress + Addend; 787 writeInt16BE(LocalAddress, applyPPClo(Delta)); 788 } break; 789 case ELF::R_PPC64_REL16_HI: { 790 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 791 uint64_t Delta = Value - FinalAddress + Addend; 792 writeInt16BE(LocalAddress, applyPPChi(Delta)); 793 } break; 794 case ELF::R_PPC64_REL16_HA: { 795 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 796 uint64_t Delta = Value - FinalAddress + Addend; 797 writeInt16BE(LocalAddress, applyPPCha(Delta)); 798 } break; 799 case ELF::R_PPC64_ADDR32: { 800 int64_t Result = static_cast<int64_t>(Value + Addend); 801 if (SignExtend64<32>(Result) != Result) 802 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 803 writeInt32BE(LocalAddress, Result); 804 } break; 805 case ELF::R_PPC64_REL24: { 806 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 807 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 808 if (SignExtend64<26>(delta) != delta) 809 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 810 // We preserve bits other than LI field, i.e. PO and AA/LK fields. 811 uint32_t Inst = readBytesUnaligned(LocalAddress, 4); 812 writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC)); 813 } break; 814 case ELF::R_PPC64_REL32: { 815 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 816 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 817 if (SignExtend64<32>(delta) != delta) 818 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 819 writeInt32BE(LocalAddress, delta); 820 } break; 821 case ELF::R_PPC64_REL64: { 822 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 823 uint64_t Delta = Value - FinalAddress + Addend; 824 writeInt64BE(LocalAddress, Delta); 825 } break; 826 case ELF::R_PPC64_ADDR64: 827 writeInt64BE(LocalAddress, Value + Addend); 828 break; 829 } 830 } 831 832 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 833 uint64_t Offset, uint64_t Value, 834 uint32_t Type, int64_t Addend) { 835 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 836 switch (Type) { 837 default: 838 report_fatal_error("Relocation type not implemented yet!"); 839 break; 840 case ELF::R_390_PC16DBL: 841 case ELF::R_390_PLT16DBL: { 842 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 843 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 844 writeInt16BE(LocalAddress, Delta / 2); 845 break; 846 } 847 case ELF::R_390_PC32DBL: 848 case ELF::R_390_PLT32DBL: { 849 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 850 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 851 writeInt32BE(LocalAddress, Delta / 2); 852 break; 853 } 854 case ELF::R_390_PC16: { 855 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 856 assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); 857 writeInt16BE(LocalAddress, Delta); 858 break; 859 } 860 case ELF::R_390_PC32: { 861 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 862 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 863 writeInt32BE(LocalAddress, Delta); 864 break; 865 } 866 case ELF::R_390_PC64: { 867 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 868 writeInt64BE(LocalAddress, Delta); 869 break; 870 } 871 case ELF::R_390_8: 872 *LocalAddress = (uint8_t)(Value + Addend); 873 break; 874 case ELF::R_390_16: 875 writeInt16BE(LocalAddress, Value + Addend); 876 break; 877 case ELF::R_390_32: 878 writeInt32BE(LocalAddress, Value + Addend); 879 break; 880 case ELF::R_390_64: 881 writeInt64BE(LocalAddress, Value + Addend); 882 break; 883 } 884 } 885 886 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 887 uint64_t Offset, uint64_t Value, 888 uint32_t Type, int64_t Addend) { 889 bool isBE = Arch == Triple::bpfeb; 890 891 switch (Type) { 892 default: 893 report_fatal_error("Relocation type not implemented yet!"); 894 break; 895 case ELF::R_BPF_NONE: 896 break; 897 case ELF::R_BPF_64_64: { 898 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 899 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 900 << format("%p\n", Section.getAddressWithOffset(Offset))); 901 break; 902 } 903 case ELF::R_BPF_64_32: { 904 Value += Addend; 905 assert(Value <= UINT32_MAX); 906 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 907 LLVM_DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 908 << format("%p\n", Section.getAddressWithOffset(Offset))); 909 break; 910 } 911 } 912 } 913 914 // The target location for the relocation is described by RE.SectionID and 915 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 916 // SectionEntry has three members describing its location. 917 // SectionEntry::Address is the address at which the section has been loaded 918 // into memory in the current (host) process. SectionEntry::LoadAddress is the 919 // address that the section will have in the target process. 920 // SectionEntry::ObjAddress is the address of the bits for this section in the 921 // original emitted object image (also in the current address space). 922 // 923 // Relocations will be applied as if the section were loaded at 924 // SectionEntry::LoadAddress, but they will be applied at an address based 925 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 926 // Target memory contents if they are required for value calculations. 927 // 928 // The Value parameter here is the load address of the symbol for the 929 // relocation to be applied. For relocations which refer to symbols in the 930 // current object Value will be the LoadAddress of the section in which 931 // the symbol resides (RE.Addend provides additional information about the 932 // symbol location). For external symbols, Value will be the address of the 933 // symbol in the target address space. 934 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 935 uint64_t Value) { 936 const SectionEntry &Section = Sections[RE.SectionID]; 937 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 938 RE.SymOffset, RE.SectionID); 939 } 940 941 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 942 uint64_t Offset, uint64_t Value, 943 uint32_t Type, int64_t Addend, 944 uint64_t SymOffset, SID SectionID) { 945 switch (Arch) { 946 case Triple::x86_64: 947 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 948 break; 949 case Triple::x86: 950 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 951 (uint32_t)(Addend & 0xffffffffL)); 952 break; 953 case Triple::aarch64: 954 case Triple::aarch64_be: 955 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 956 break; 957 case Triple::arm: // Fall through. 958 case Triple::armeb: 959 case Triple::thumb: 960 case Triple::thumbeb: 961 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 962 (uint32_t)(Addend & 0xffffffffL)); 963 break; 964 case Triple::ppc: 965 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 966 break; 967 case Triple::ppc64: // Fall through. 968 case Triple::ppc64le: 969 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 970 break; 971 case Triple::systemz: 972 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 973 break; 974 case Triple::bpfel: 975 case Triple::bpfeb: 976 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 977 break; 978 default: 979 llvm_unreachable("Unsupported CPU type!"); 980 } 981 } 982 983 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 984 return (void *)(Sections[SectionID].getObjAddress() + Offset); 985 } 986 987 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 988 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 989 if (Value.SymbolName) 990 addRelocationForSymbol(RE, Value.SymbolName); 991 else 992 addRelocationForSection(RE, Value.SectionID); 993 } 994 995 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 996 bool IsLocal) const { 997 switch (RelType) { 998 case ELF::R_MICROMIPS_GOT16: 999 if (IsLocal) 1000 return ELF::R_MICROMIPS_LO16; 1001 break; 1002 case ELF::R_MICROMIPS_HI16: 1003 return ELF::R_MICROMIPS_LO16; 1004 case ELF::R_MIPS_GOT16: 1005 if (IsLocal) 1006 return ELF::R_MIPS_LO16; 1007 break; 1008 case ELF::R_MIPS_HI16: 1009 return ELF::R_MIPS_LO16; 1010 case ELF::R_MIPS_PCHI16: 1011 return ELF::R_MIPS_PCLO16; 1012 default: 1013 break; 1014 } 1015 return ELF::R_MIPS_NONE; 1016 } 1017 1018 // Sometimes we don't need to create thunk for a branch. 1019 // This typically happens when branch target is located 1020 // in the same object file. In such case target is either 1021 // a weak symbol or symbol in a different executable section. 1022 // This function checks if branch target is located in the 1023 // same object file and if distance between source and target 1024 // fits R_AARCH64_CALL26 relocation. If both conditions are 1025 // met, it emits direct jump to the target and returns true. 1026 // Otherwise false is returned and thunk is created. 1027 bool RuntimeDyldELF::resolveAArch64ShortBranch( 1028 unsigned SectionID, relocation_iterator RelI, 1029 const RelocationValueRef &Value) { 1030 uint64_t Address; 1031 if (Value.SymbolName) { 1032 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 1033 1034 // Don't create direct branch for external symbols. 1035 if (Loc == GlobalSymbolTable.end()) 1036 return false; 1037 1038 const auto &SymInfo = Loc->second; 1039 Address = 1040 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 1041 SymInfo.getOffset())); 1042 } else { 1043 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 1044 } 1045 uint64_t Offset = RelI->getOffset(); 1046 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 1047 1048 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 1049 // If distance between source and target is out of range then we should 1050 // create thunk. 1051 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 1052 return false; 1053 1054 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 1055 Value.Addend); 1056 1057 return true; 1058 } 1059 1060 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 1061 const RelocationValueRef &Value, 1062 relocation_iterator RelI, 1063 StubMap &Stubs) { 1064 1065 LLVM_DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1066 SectionEntry &Section = Sections[SectionID]; 1067 1068 uint64_t Offset = RelI->getOffset(); 1069 unsigned RelType = RelI->getType(); 1070 // Look for an existing stub. 1071 StubMap::const_iterator i = Stubs.find(Value); 1072 if (i != Stubs.end()) { 1073 resolveRelocation(Section, Offset, 1074 (uint64_t)Section.getAddressWithOffset(i->second), 1075 RelType, 0); 1076 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1077 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1078 // Create a new stub function. 1079 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1080 Stubs[Value] = Section.getStubOffset(); 1081 uint8_t *StubTargetAddr = createStubFunction( 1082 Section.getAddressWithOffset(Section.getStubOffset())); 1083 1084 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1085 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1086 RelocationEntry REmovk_g2(SectionID, 1087 StubTargetAddr - Section.getAddress() + 4, 1088 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1089 RelocationEntry REmovk_g1(SectionID, 1090 StubTargetAddr - Section.getAddress() + 8, 1091 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1092 RelocationEntry REmovk_g0(SectionID, 1093 StubTargetAddr - Section.getAddress() + 12, 1094 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1095 1096 if (Value.SymbolName) { 1097 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1098 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1099 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1100 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1101 } else { 1102 addRelocationForSection(REmovz_g3, Value.SectionID); 1103 addRelocationForSection(REmovk_g2, Value.SectionID); 1104 addRelocationForSection(REmovk_g1, Value.SectionID); 1105 addRelocationForSection(REmovk_g0, Value.SectionID); 1106 } 1107 resolveRelocation(Section, Offset, 1108 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1109 Section.getStubOffset())), 1110 RelType, 0); 1111 Section.advanceStubOffset(getMaxStubSize()); 1112 } 1113 } 1114 1115 Expected<relocation_iterator> 1116 RuntimeDyldELF::processRelocationRef( 1117 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1118 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1119 const auto &Obj = cast<ELFObjectFileBase>(O); 1120 uint64_t RelType = RelI->getType(); 1121 int64_t Addend = 0; 1122 if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend()) 1123 Addend = *AddendOrErr; 1124 else 1125 consumeError(AddendOrErr.takeError()); 1126 elf_symbol_iterator Symbol = RelI->getSymbol(); 1127 1128 // Obtain the symbol name which is referenced in the relocation 1129 StringRef TargetName; 1130 if (Symbol != Obj.symbol_end()) { 1131 if (auto TargetNameOrErr = Symbol->getName()) 1132 TargetName = *TargetNameOrErr; 1133 else 1134 return TargetNameOrErr.takeError(); 1135 } 1136 LLVM_DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1137 << " TargetName: " << TargetName << "\n"); 1138 RelocationValueRef Value; 1139 // First search for the symbol in the local symbol table 1140 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1141 1142 // Search for the symbol in the global symbol table 1143 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1144 if (Symbol != Obj.symbol_end()) { 1145 gsi = GlobalSymbolTable.find(TargetName.data()); 1146 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1147 if (!SymTypeOrErr) { 1148 std::string Buf; 1149 raw_string_ostream OS(Buf); 1150 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS); 1151 OS.flush(); 1152 report_fatal_error(Buf); 1153 } 1154 SymType = *SymTypeOrErr; 1155 } 1156 if (gsi != GlobalSymbolTable.end()) { 1157 const auto &SymInfo = gsi->second; 1158 Value.SectionID = SymInfo.getSectionID(); 1159 Value.Offset = SymInfo.getOffset(); 1160 Value.Addend = SymInfo.getOffset() + Addend; 1161 } else { 1162 switch (SymType) { 1163 case SymbolRef::ST_Debug: { 1164 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1165 // and can be changed by another developers. Maybe best way is add 1166 // a new symbol type ST_Section to SymbolRef and use it. 1167 auto SectionOrErr = Symbol->getSection(); 1168 if (!SectionOrErr) { 1169 std::string Buf; 1170 raw_string_ostream OS(Buf); 1171 logAllUnhandledErrors(SectionOrErr.takeError(), OS); 1172 OS.flush(); 1173 report_fatal_error(Buf); 1174 } 1175 section_iterator si = *SectionOrErr; 1176 if (si == Obj.section_end()) 1177 llvm_unreachable("Symbol section not found, bad object file format!"); 1178 LLVM_DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1179 bool isCode = si->isText(); 1180 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1181 ObjSectionToID)) 1182 Value.SectionID = *SectionIDOrErr; 1183 else 1184 return SectionIDOrErr.takeError(); 1185 Value.Addend = Addend; 1186 break; 1187 } 1188 case SymbolRef::ST_Data: 1189 case SymbolRef::ST_Function: 1190 case SymbolRef::ST_Unknown: { 1191 Value.SymbolName = TargetName.data(); 1192 Value.Addend = Addend; 1193 1194 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1195 // will manifest here as a NULL symbol name. 1196 // We can set this as a valid (but empty) symbol name, and rely 1197 // on addRelocationForSymbol to handle this. 1198 if (!Value.SymbolName) 1199 Value.SymbolName = ""; 1200 break; 1201 } 1202 default: 1203 llvm_unreachable("Unresolved symbol type!"); 1204 break; 1205 } 1206 } 1207 1208 uint64_t Offset = RelI->getOffset(); 1209 1210 LLVM_DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1211 << "\n"); 1212 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1213 if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { 1214 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1215 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1216 // Craete new GOT entry or find existing one. If GOT entry is 1217 // to be created, then we also emit ABS64 relocation for it. 1218 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1219 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1220 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1221 1222 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1223 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1224 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1225 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1226 } else { 1227 processSimpleRelocation(SectionID, Offset, RelType, Value); 1228 } 1229 } else if (Arch == Triple::arm) { 1230 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1231 RelType == ELF::R_ARM_JUMP24) { 1232 // This is an ARM branch relocation, need to use a stub function. 1233 LLVM_DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1234 SectionEntry &Section = Sections[SectionID]; 1235 1236 // Look for an existing stub. 1237 StubMap::const_iterator i = Stubs.find(Value); 1238 if (i != Stubs.end()) { 1239 resolveRelocation( 1240 Section, Offset, 1241 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1242 RelType, 0); 1243 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1244 } else { 1245 // Create a new stub function. 1246 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1247 Stubs[Value] = Section.getStubOffset(); 1248 uint8_t *StubTargetAddr = createStubFunction( 1249 Section.getAddressWithOffset(Section.getStubOffset())); 1250 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1251 ELF::R_ARM_ABS32, Value.Addend); 1252 if (Value.SymbolName) 1253 addRelocationForSymbol(RE, Value.SymbolName); 1254 else 1255 addRelocationForSection(RE, Value.SectionID); 1256 1257 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1258 Section.getAddressWithOffset( 1259 Section.getStubOffset())), 1260 RelType, 0); 1261 Section.advanceStubOffset(getMaxStubSize()); 1262 } 1263 } else { 1264 uint32_t *Placeholder = 1265 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1266 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1267 RelType == ELF::R_ARM_ABS32) { 1268 Value.Addend += *Placeholder; 1269 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1270 // See ELF for ARM documentation 1271 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1272 } 1273 processSimpleRelocation(SectionID, Offset, RelType, Value); 1274 } 1275 } else if (IsMipsO32ABI) { 1276 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1277 computePlaceholderAddress(SectionID, Offset)); 1278 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1279 if (RelType == ELF::R_MIPS_26) { 1280 // This is an Mips branch relocation, need to use a stub function. 1281 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1282 SectionEntry &Section = Sections[SectionID]; 1283 1284 // Extract the addend from the instruction. 1285 // We shift up by two since the Value will be down shifted again 1286 // when applying the relocation. 1287 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1288 1289 Value.Addend += Addend; 1290 1291 // Look up for existing stub. 1292 StubMap::const_iterator i = Stubs.find(Value); 1293 if (i != Stubs.end()) { 1294 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1295 addRelocationForSection(RE, SectionID); 1296 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1297 } else { 1298 // Create a new stub function. 1299 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1300 Stubs[Value] = Section.getStubOffset(); 1301 1302 unsigned AbiVariant = Obj.getPlatformFlags(); 1303 1304 uint8_t *StubTargetAddr = createStubFunction( 1305 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1306 1307 // Creating Hi and Lo relocations for the filled stub instructions. 1308 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1309 ELF::R_MIPS_HI16, Value.Addend); 1310 RelocationEntry RELo(SectionID, 1311 StubTargetAddr - Section.getAddress() + 4, 1312 ELF::R_MIPS_LO16, Value.Addend); 1313 1314 if (Value.SymbolName) { 1315 addRelocationForSymbol(REHi, Value.SymbolName); 1316 addRelocationForSymbol(RELo, Value.SymbolName); 1317 } else { 1318 addRelocationForSection(REHi, Value.SectionID); 1319 addRelocationForSection(RELo, Value.SectionID); 1320 } 1321 1322 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1323 addRelocationForSection(RE, SectionID); 1324 Section.advanceStubOffset(getMaxStubSize()); 1325 } 1326 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1327 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1328 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1329 PendingRelocs.push_back(std::make_pair(Value, RE)); 1330 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1331 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1332 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1333 const RelocationValueRef &MatchingValue = I->first; 1334 RelocationEntry &Reloc = I->second; 1335 if (MatchingValue == Value && 1336 RelType == getMatchingLoRelocation(Reloc.RelType) && 1337 SectionID == Reloc.SectionID) { 1338 Reloc.Addend += Addend; 1339 if (Value.SymbolName) 1340 addRelocationForSymbol(Reloc, Value.SymbolName); 1341 else 1342 addRelocationForSection(Reloc, Value.SectionID); 1343 I = PendingRelocs.erase(I); 1344 } else 1345 ++I; 1346 } 1347 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1348 if (Value.SymbolName) 1349 addRelocationForSymbol(RE, Value.SymbolName); 1350 else 1351 addRelocationForSection(RE, Value.SectionID); 1352 } else { 1353 if (RelType == ELF::R_MIPS_32) 1354 Value.Addend += Opcode; 1355 else if (RelType == ELF::R_MIPS_PC16) 1356 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1357 else if (RelType == ELF::R_MIPS_PC19_S2) 1358 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1359 else if (RelType == ELF::R_MIPS_PC21_S2) 1360 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1361 else if (RelType == ELF::R_MIPS_PC26_S2) 1362 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1363 processSimpleRelocation(SectionID, Offset, RelType, Value); 1364 } 1365 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1366 uint32_t r_type = RelType & 0xff; 1367 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1368 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1369 || r_type == ELF::R_MIPS_GOT_DISP) { 1370 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1371 if (i != GOTSymbolOffsets.end()) 1372 RE.SymOffset = i->second; 1373 else { 1374 RE.SymOffset = allocateGOTEntries(1); 1375 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1376 } 1377 if (Value.SymbolName) 1378 addRelocationForSymbol(RE, Value.SymbolName); 1379 else 1380 addRelocationForSection(RE, Value.SectionID); 1381 } else if (RelType == ELF::R_MIPS_26) { 1382 // This is an Mips branch relocation, need to use a stub function. 1383 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1384 SectionEntry &Section = Sections[SectionID]; 1385 1386 // Look up for existing stub. 1387 StubMap::const_iterator i = Stubs.find(Value); 1388 if (i != Stubs.end()) { 1389 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1390 addRelocationForSection(RE, SectionID); 1391 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1392 } else { 1393 // Create a new stub function. 1394 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1395 Stubs[Value] = Section.getStubOffset(); 1396 1397 unsigned AbiVariant = Obj.getPlatformFlags(); 1398 1399 uint8_t *StubTargetAddr = createStubFunction( 1400 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1401 1402 if (IsMipsN32ABI) { 1403 // Creating Hi and Lo relocations for the filled stub instructions. 1404 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1405 ELF::R_MIPS_HI16, Value.Addend); 1406 RelocationEntry RELo(SectionID, 1407 StubTargetAddr - Section.getAddress() + 4, 1408 ELF::R_MIPS_LO16, Value.Addend); 1409 if (Value.SymbolName) { 1410 addRelocationForSymbol(REHi, Value.SymbolName); 1411 addRelocationForSymbol(RELo, Value.SymbolName); 1412 } else { 1413 addRelocationForSection(REHi, Value.SectionID); 1414 addRelocationForSection(RELo, Value.SectionID); 1415 } 1416 } else { 1417 // Creating Highest, Higher, Hi and Lo relocations for the filled stub 1418 // instructions. 1419 RelocationEntry REHighest(SectionID, 1420 StubTargetAddr - Section.getAddress(), 1421 ELF::R_MIPS_HIGHEST, Value.Addend); 1422 RelocationEntry REHigher(SectionID, 1423 StubTargetAddr - Section.getAddress() + 4, 1424 ELF::R_MIPS_HIGHER, Value.Addend); 1425 RelocationEntry REHi(SectionID, 1426 StubTargetAddr - Section.getAddress() + 12, 1427 ELF::R_MIPS_HI16, Value.Addend); 1428 RelocationEntry RELo(SectionID, 1429 StubTargetAddr - Section.getAddress() + 20, 1430 ELF::R_MIPS_LO16, Value.Addend); 1431 if (Value.SymbolName) { 1432 addRelocationForSymbol(REHighest, Value.SymbolName); 1433 addRelocationForSymbol(REHigher, Value.SymbolName); 1434 addRelocationForSymbol(REHi, Value.SymbolName); 1435 addRelocationForSymbol(RELo, Value.SymbolName); 1436 } else { 1437 addRelocationForSection(REHighest, Value.SectionID); 1438 addRelocationForSection(REHigher, Value.SectionID); 1439 addRelocationForSection(REHi, Value.SectionID); 1440 addRelocationForSection(RELo, Value.SectionID); 1441 } 1442 } 1443 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1444 addRelocationForSection(RE, SectionID); 1445 Section.advanceStubOffset(getMaxStubSize()); 1446 } 1447 } else { 1448 processSimpleRelocation(SectionID, Offset, RelType, Value); 1449 } 1450 1451 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1452 if (RelType == ELF::R_PPC64_REL24) { 1453 // Determine ABI variant in use for this object. 1454 unsigned AbiVariant = Obj.getPlatformFlags(); 1455 AbiVariant &= ELF::EF_PPC64_ABI; 1456 // A PPC branch relocation will need a stub function if the target is 1457 // an external symbol (either Value.SymbolName is set, or SymType is 1458 // Symbol::ST_Unknown) or if the target address is not within the 1459 // signed 24-bits branch address. 1460 SectionEntry &Section = Sections[SectionID]; 1461 uint8_t *Target = Section.getAddressWithOffset(Offset); 1462 bool RangeOverflow = false; 1463 bool IsExtern = Value.SymbolName || SymType == SymbolRef::ST_Unknown; 1464 if (!IsExtern) { 1465 if (AbiVariant != 2) { 1466 // In the ELFv1 ABI, a function call may point to the .opd entry, 1467 // so the final symbol value is calculated based on the relocation 1468 // values in the .opd section. 1469 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1470 return std::move(Err); 1471 } else { 1472 // In the ELFv2 ABI, a function symbol may provide a local entry 1473 // point, which must be used for direct calls. 1474 if (Value.SectionID == SectionID){ 1475 uint8_t SymOther = Symbol->getOther(); 1476 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1477 } 1478 } 1479 uint8_t *RelocTarget = 1480 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1481 int64_t delta = static_cast<int64_t>(Target - RelocTarget); 1482 // If it is within 26-bits branch range, just set the branch target 1483 if (SignExtend64<26>(delta) != delta) { 1484 RangeOverflow = true; 1485 } else if ((AbiVariant != 2) || 1486 (AbiVariant == 2 && Value.SectionID == SectionID)) { 1487 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1488 addRelocationForSection(RE, Value.SectionID); 1489 } 1490 } 1491 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID) || 1492 RangeOverflow) { 1493 // It is an external symbol (either Value.SymbolName is set, or 1494 // SymType is SymbolRef::ST_Unknown) or out of range. 1495 StubMap::const_iterator i = Stubs.find(Value); 1496 if (i != Stubs.end()) { 1497 // Symbol function stub already created, just relocate to it 1498 resolveRelocation(Section, Offset, 1499 reinterpret_cast<uint64_t>( 1500 Section.getAddressWithOffset(i->second)), 1501 RelType, 0); 1502 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1503 } else { 1504 // Create a new stub function. 1505 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1506 Stubs[Value] = Section.getStubOffset(); 1507 uint8_t *StubTargetAddr = createStubFunction( 1508 Section.getAddressWithOffset(Section.getStubOffset()), 1509 AbiVariant); 1510 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1511 ELF::R_PPC64_ADDR64, Value.Addend); 1512 1513 // Generates the 64-bits address loads as exemplified in section 1514 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1515 // apply to the low part of the instructions, so we have to update 1516 // the offset according to the target endianness. 1517 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1518 if (!IsTargetLittleEndian) 1519 StubRelocOffset += 2; 1520 1521 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1522 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1523 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1524 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1525 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1526 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1527 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1528 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1529 1530 if (Value.SymbolName) { 1531 addRelocationForSymbol(REhst, Value.SymbolName); 1532 addRelocationForSymbol(REhr, Value.SymbolName); 1533 addRelocationForSymbol(REh, Value.SymbolName); 1534 addRelocationForSymbol(REl, Value.SymbolName); 1535 } else { 1536 addRelocationForSection(REhst, Value.SectionID); 1537 addRelocationForSection(REhr, Value.SectionID); 1538 addRelocationForSection(REh, Value.SectionID); 1539 addRelocationForSection(REl, Value.SectionID); 1540 } 1541 1542 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1543 Section.getAddressWithOffset( 1544 Section.getStubOffset())), 1545 RelType, 0); 1546 Section.advanceStubOffset(getMaxStubSize()); 1547 } 1548 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID)) { 1549 // Restore the TOC for external calls 1550 if (AbiVariant == 2) 1551 writeInt32BE(Target + 4, 0xE8410018); // ld r2,24(r1) 1552 else 1553 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1554 } 1555 } 1556 } else if (RelType == ELF::R_PPC64_TOC16 || 1557 RelType == ELF::R_PPC64_TOC16_DS || 1558 RelType == ELF::R_PPC64_TOC16_LO || 1559 RelType == ELF::R_PPC64_TOC16_LO_DS || 1560 RelType == ELF::R_PPC64_TOC16_HI || 1561 RelType == ELF::R_PPC64_TOC16_HA) { 1562 // These relocations are supposed to subtract the TOC address from 1563 // the final value. This does not fit cleanly into the RuntimeDyld 1564 // scheme, since there may be *two* sections involved in determining 1565 // the relocation value (the section of the symbol referred to by the 1566 // relocation, and the TOC section associated with the current module). 1567 // 1568 // Fortunately, these relocations are currently only ever generated 1569 // referring to symbols that themselves reside in the TOC, which means 1570 // that the two sections are actually the same. Thus they cancel out 1571 // and we can immediately resolve the relocation right now. 1572 switch (RelType) { 1573 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1574 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1575 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1576 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1577 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1578 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1579 default: llvm_unreachable("Wrong relocation type."); 1580 } 1581 1582 RelocationValueRef TOCValue; 1583 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1584 return std::move(Err); 1585 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1586 llvm_unreachable("Unsupported TOC relocation."); 1587 Value.Addend -= TOCValue.Addend; 1588 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1589 } else { 1590 // There are two ways to refer to the TOC address directly: either 1591 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1592 // ignored), or via any relocation that refers to the magic ".TOC." 1593 // symbols (in which case the addend is respected). 1594 if (RelType == ELF::R_PPC64_TOC) { 1595 RelType = ELF::R_PPC64_ADDR64; 1596 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1597 return std::move(Err); 1598 } else if (TargetName == ".TOC.") { 1599 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1600 return std::move(Err); 1601 Value.Addend += Addend; 1602 } 1603 1604 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1605 1606 if (Value.SymbolName) 1607 addRelocationForSymbol(RE, Value.SymbolName); 1608 else 1609 addRelocationForSection(RE, Value.SectionID); 1610 } 1611 } else if (Arch == Triple::systemz && 1612 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1613 // Create function stubs for both PLT and GOT references, regardless of 1614 // whether the GOT reference is to data or code. The stub contains the 1615 // full address of the symbol, as needed by GOT references, and the 1616 // executable part only adds an overhead of 8 bytes. 1617 // 1618 // We could try to conserve space by allocating the code and data 1619 // parts of the stub separately. However, as things stand, we allocate 1620 // a stub for every relocation, so using a GOT in JIT code should be 1621 // no less space efficient than using an explicit constant pool. 1622 LLVM_DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1623 SectionEntry &Section = Sections[SectionID]; 1624 1625 // Look for an existing stub. 1626 StubMap::const_iterator i = Stubs.find(Value); 1627 uintptr_t StubAddress; 1628 if (i != Stubs.end()) { 1629 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1630 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1631 } else { 1632 // Create a new stub function. 1633 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1634 1635 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1636 uintptr_t StubAlignment = getStubAlignment(); 1637 StubAddress = 1638 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1639 -StubAlignment; 1640 unsigned StubOffset = StubAddress - BaseAddress; 1641 1642 Stubs[Value] = StubOffset; 1643 createStubFunction((uint8_t *)StubAddress); 1644 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1645 Value.Offset); 1646 if (Value.SymbolName) 1647 addRelocationForSymbol(RE, Value.SymbolName); 1648 else 1649 addRelocationForSection(RE, Value.SectionID); 1650 Section.advanceStubOffset(getMaxStubSize()); 1651 } 1652 1653 if (RelType == ELF::R_390_GOTENT) 1654 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1655 Addend); 1656 else 1657 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1658 } else if (Arch == Triple::x86_64) { 1659 if (RelType == ELF::R_X86_64_PLT32) { 1660 // The way the PLT relocations normally work is that the linker allocates 1661 // the 1662 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1663 // entry will then jump to an address provided by the GOT. On first call, 1664 // the 1665 // GOT address will point back into PLT code that resolves the symbol. After 1666 // the first call, the GOT entry points to the actual function. 1667 // 1668 // For local functions we're ignoring all of that here and just replacing 1669 // the PLT32 relocation type with PC32, which will translate the relocation 1670 // into a PC-relative call directly to the function. For external symbols we 1671 // can't be sure the function will be within 2^32 bytes of the call site, so 1672 // we need to create a stub, which calls into the GOT. This case is 1673 // equivalent to the usual PLT implementation except that we use the stub 1674 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1675 // rather than allocating a PLT section. 1676 if (Value.SymbolName) { 1677 // This is a call to an external function. 1678 // Look for an existing stub. 1679 SectionEntry &Section = Sections[SectionID]; 1680 StubMap::const_iterator i = Stubs.find(Value); 1681 uintptr_t StubAddress; 1682 if (i != Stubs.end()) { 1683 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1684 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1685 } else { 1686 // Create a new stub function (equivalent to a PLT entry). 1687 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1688 1689 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1690 uintptr_t StubAlignment = getStubAlignment(); 1691 StubAddress = 1692 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1693 -StubAlignment; 1694 unsigned StubOffset = StubAddress - BaseAddress; 1695 Stubs[Value] = StubOffset; 1696 createStubFunction((uint8_t *)StubAddress); 1697 1698 // Bump our stub offset counter 1699 Section.advanceStubOffset(getMaxStubSize()); 1700 1701 // Allocate a GOT Entry 1702 uint64_t GOTOffset = allocateGOTEntries(1); 1703 1704 // The load of the GOT address has an addend of -4 1705 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1706 ELF::R_X86_64_PC32); 1707 1708 // Fill in the value of the symbol we're targeting into the GOT 1709 addRelocationForSymbol( 1710 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1711 Value.SymbolName); 1712 } 1713 1714 // Make the target call a call into the stub table. 1715 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1716 Addend); 1717 } else { 1718 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1719 Value.Offset); 1720 addRelocationForSection(RE, Value.SectionID); 1721 } 1722 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1723 RelType == ELF::R_X86_64_GOTPCRELX || 1724 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1725 uint64_t GOTOffset = allocateGOTEntries(1); 1726 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1727 ELF::R_X86_64_PC32); 1728 1729 // Fill in the value of the symbol we're targeting into the GOT 1730 RelocationEntry RE = 1731 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1732 if (Value.SymbolName) 1733 addRelocationForSymbol(RE, Value.SymbolName); 1734 else 1735 addRelocationForSection(RE, Value.SectionID); 1736 } else if (RelType == ELF::R_X86_64_GOT64) { 1737 // Fill in a 64-bit GOT offset. 1738 uint64_t GOTOffset = allocateGOTEntries(1); 1739 resolveRelocation(Sections[SectionID], Offset, GOTOffset, 1740 ELF::R_X86_64_64, 0); 1741 1742 // Fill in the value of the symbol we're targeting into the GOT 1743 RelocationEntry RE = 1744 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1745 if (Value.SymbolName) 1746 addRelocationForSymbol(RE, Value.SymbolName); 1747 else 1748 addRelocationForSection(RE, Value.SectionID); 1749 } else if (RelType == ELF::R_X86_64_GOTPC64) { 1750 // Materialize the address of the base of the GOT relative to the PC. 1751 // This doesn't create a GOT entry, but it does mean we need a GOT 1752 // section. 1753 (void)allocateGOTEntries(0); 1754 resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC64); 1755 } else if (RelType == ELF::R_X86_64_GOTOFF64) { 1756 // GOTOFF relocations ultimately require a section difference relocation. 1757 (void)allocateGOTEntries(0); 1758 processSimpleRelocation(SectionID, Offset, RelType, Value); 1759 } else if (RelType == ELF::R_X86_64_PC32) { 1760 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1761 processSimpleRelocation(SectionID, Offset, RelType, Value); 1762 } else if (RelType == ELF::R_X86_64_PC64) { 1763 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1764 processSimpleRelocation(SectionID, Offset, RelType, Value); 1765 } else { 1766 processSimpleRelocation(SectionID, Offset, RelType, Value); 1767 } 1768 } else { 1769 if (Arch == Triple::x86) { 1770 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1771 } 1772 processSimpleRelocation(SectionID, Offset, RelType, Value); 1773 } 1774 return ++RelI; 1775 } 1776 1777 size_t RuntimeDyldELF::getGOTEntrySize() { 1778 // We don't use the GOT in all of these cases, but it's essentially free 1779 // to put them all here. 1780 size_t Result = 0; 1781 switch (Arch) { 1782 case Triple::x86_64: 1783 case Triple::aarch64: 1784 case Triple::aarch64_be: 1785 case Triple::ppc64: 1786 case Triple::ppc64le: 1787 case Triple::systemz: 1788 Result = sizeof(uint64_t); 1789 break; 1790 case Triple::x86: 1791 case Triple::arm: 1792 case Triple::thumb: 1793 Result = sizeof(uint32_t); 1794 break; 1795 case Triple::mips: 1796 case Triple::mipsel: 1797 case Triple::mips64: 1798 case Triple::mips64el: 1799 if (IsMipsO32ABI || IsMipsN32ABI) 1800 Result = sizeof(uint32_t); 1801 else if (IsMipsN64ABI) 1802 Result = sizeof(uint64_t); 1803 else 1804 llvm_unreachable("Mips ABI not handled"); 1805 break; 1806 default: 1807 llvm_unreachable("Unsupported CPU type!"); 1808 } 1809 return Result; 1810 } 1811 1812 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 1813 if (GOTSectionID == 0) { 1814 GOTSectionID = Sections.size(); 1815 // Reserve a section id. We'll allocate the section later 1816 // once we know the total size 1817 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1818 } 1819 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1820 CurrentGOTIndex += no; 1821 return StartOffset; 1822 } 1823 1824 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 1825 unsigned GOTRelType) { 1826 auto E = GOTOffsetMap.insert({Value, 0}); 1827 if (E.second) { 1828 uint64_t GOTOffset = allocateGOTEntries(1); 1829 1830 // Create relocation for newly created GOT entry 1831 RelocationEntry RE = 1832 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 1833 if (Value.SymbolName) 1834 addRelocationForSymbol(RE, Value.SymbolName); 1835 else 1836 addRelocationForSection(RE, Value.SectionID); 1837 1838 E.first->second = GOTOffset; 1839 } 1840 1841 return E.first->second; 1842 } 1843 1844 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 1845 uint64_t Offset, 1846 uint64_t GOTOffset, 1847 uint32_t Type) { 1848 // Fill in the relative address of the GOT Entry into the stub 1849 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 1850 addRelocationForSection(GOTRE, GOTSectionID); 1851 } 1852 1853 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 1854 uint64_t SymbolOffset, 1855 uint32_t Type) { 1856 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1857 } 1858 1859 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1860 ObjSectionToIDMap &SectionMap) { 1861 if (IsMipsO32ABI) 1862 if (!PendingRelocs.empty()) 1863 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1864 1865 // If necessary, allocate the global offset table 1866 if (GOTSectionID != 0) { 1867 // Allocate memory for the section 1868 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1869 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1870 GOTSectionID, ".got", false); 1871 if (!Addr) 1872 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1873 1874 Sections[GOTSectionID] = 1875 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1876 1877 // For now, initialize all GOT entries to zero. We'll fill them in as 1878 // needed when GOT-based relocations are applied. 1879 memset(Addr, 0, TotalSize); 1880 if (IsMipsN32ABI || IsMipsN64ABI) { 1881 // To correctly resolve Mips GOT relocations, we need a mapping from 1882 // object's sections to GOTs. 1883 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1884 SI != SE; ++SI) { 1885 if (SI->relocation_begin() != SI->relocation_end()) { 1886 Expected<section_iterator> RelSecOrErr = SI->getRelocatedSection(); 1887 if (!RelSecOrErr) 1888 return make_error<RuntimeDyldError>( 1889 toString(RelSecOrErr.takeError())); 1890 1891 section_iterator RelocatedSection = *RelSecOrErr; 1892 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1893 assert (i != SectionMap.end()); 1894 SectionToGOTMap[i->second] = GOTSectionID; 1895 } 1896 } 1897 GOTSymbolOffsets.clear(); 1898 } 1899 } 1900 1901 // Look for and record the EH frame section. 1902 ObjSectionToIDMap::iterator i, e; 1903 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1904 const SectionRef &Section = i->first; 1905 1906 StringRef Name; 1907 Expected<StringRef> NameOrErr = Section.getName(); 1908 if (NameOrErr) 1909 Name = *NameOrErr; 1910 else 1911 consumeError(NameOrErr.takeError()); 1912 1913 if (Name == ".eh_frame") { 1914 UnregisteredEHFrameSections.push_back(i->second); 1915 break; 1916 } 1917 } 1918 1919 GOTSectionID = 0; 1920 CurrentGOTIndex = 0; 1921 1922 return Error::success(); 1923 } 1924 1925 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1926 return Obj.isELF(); 1927 } 1928 1929 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 1930 unsigned RelTy = R.getType(); 1931 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 1932 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 1933 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 1934 1935 if (Arch == Triple::x86_64) 1936 return RelTy == ELF::R_X86_64_GOTPCREL || 1937 RelTy == ELF::R_X86_64_GOTPCRELX || 1938 RelTy == ELF::R_X86_64_GOT64 || 1939 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 1940 return false; 1941 } 1942 1943 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1944 if (Arch != Triple::x86_64) 1945 return true; // Conservative answer 1946 1947 switch (R.getType()) { 1948 default: 1949 return true; // Conservative answer 1950 1951 1952 case ELF::R_X86_64_GOTPCREL: 1953 case ELF::R_X86_64_GOTPCRELX: 1954 case ELF::R_X86_64_REX_GOTPCRELX: 1955 case ELF::R_X86_64_GOTPC64: 1956 case ELF::R_X86_64_GOT64: 1957 case ELF::R_X86_64_GOTOFF64: 1958 case ELF::R_X86_64_PC32: 1959 case ELF::R_X86_64_PC64: 1960 case ELF::R_X86_64_64: 1961 // We know that these reloation types won't need a stub function. This list 1962 // can be extended as needed. 1963 return false; 1964 } 1965 } 1966 1967 } // namespace llvm 1968