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 StringRef SectionName; 164 Sec.getName(SectionName); 165 if (SectionName != "") { 166 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 167 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 168 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 169 170 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { 171 // This assumes that the address passed in matches the target address 172 // bitness. The template-based type cast handles everything else. 173 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 174 } 175 } 176 ++SI; 177 } 178 179 return std::move(Obj); 180 } 181 182 static OwningBinary<ObjectFile> 183 createELFDebugObject(const ObjectFile &Obj, const LoadedELFObjectInfo &L) { 184 assert(Obj.isELF() && "Not an ELF object file."); 185 186 std::unique_ptr<MemoryBuffer> Buffer = 187 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 188 189 Expected<std::unique_ptr<ObjectFile>> DebugObj(nullptr); 190 handleAllErrors(DebugObj.takeError()); 191 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) 192 DebugObj = 193 createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L); 194 else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) 195 DebugObj = 196 createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L); 197 else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) 198 DebugObj = 199 createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L); 200 else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) 201 DebugObj = 202 createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L); 203 else 204 llvm_unreachable("Unexpected ELF format"); 205 206 handleAllErrors(DebugObj.takeError()); 207 return OwningBinary<ObjectFile>(std::move(*DebugObj), std::move(Buffer)); 208 } 209 210 OwningBinary<ObjectFile> 211 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 212 return createELFDebugObject(Obj, *this); 213 } 214 215 } // anonymous namespace 216 217 namespace llvm { 218 219 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 220 JITSymbolResolver &Resolver) 221 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 222 RuntimeDyldELF::~RuntimeDyldELF() {} 223 224 void RuntimeDyldELF::registerEHFrames() { 225 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { 226 SID EHFrameSID = UnregisteredEHFrameSections[i]; 227 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 228 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 229 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 230 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 231 } 232 UnregisteredEHFrameSections.clear(); 233 } 234 235 std::unique_ptr<RuntimeDyldELF> 236 llvm::RuntimeDyldELF::create(Triple::ArchType Arch, 237 RuntimeDyld::MemoryManager &MemMgr, 238 JITSymbolResolver &Resolver) { 239 switch (Arch) { 240 default: 241 return make_unique<RuntimeDyldELF>(MemMgr, Resolver); 242 case Triple::mips: 243 case Triple::mipsel: 244 case Triple::mips64: 245 case Triple::mips64el: 246 return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); 247 } 248 } 249 250 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 251 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 252 if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) 253 return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); 254 else { 255 HasError = true; 256 raw_string_ostream ErrStream(ErrorStr); 257 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream); 258 return nullptr; 259 } 260 } 261 262 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 263 uint64_t Offset, uint64_t Value, 264 uint32_t Type, int64_t Addend, 265 uint64_t SymOffset) { 266 switch (Type) { 267 default: 268 llvm_unreachable("Relocation type not implemented yet!"); 269 break; 270 case ELF::R_X86_64_NONE: 271 break; 272 case ELF::R_X86_64_64: { 273 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 274 Value + Addend; 275 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 276 << format("%p\n", Section.getAddressWithOffset(Offset))); 277 break; 278 } 279 case ELF::R_X86_64_32: 280 case ELF::R_X86_64_32S: { 281 Value += Addend; 282 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 283 (Type == ELF::R_X86_64_32S && 284 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 285 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 286 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 287 TruncatedAddr; 288 LLVM_DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 289 << format("%p\n", Section.getAddressWithOffset(Offset))); 290 break; 291 } 292 case ELF::R_X86_64_PC8: { 293 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 294 int64_t RealOffset = Value + Addend - FinalAddress; 295 assert(isInt<8>(RealOffset)); 296 int8_t TruncOffset = (RealOffset & 0xFF); 297 Section.getAddress()[Offset] = TruncOffset; 298 break; 299 } 300 case ELF::R_X86_64_PC32: { 301 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 302 int64_t RealOffset = Value + Addend - FinalAddress; 303 assert(isInt<32>(RealOffset)); 304 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 305 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 306 TruncOffset; 307 break; 308 } 309 case ELF::R_X86_64_PC64: { 310 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 311 int64_t RealOffset = Value + Addend - FinalAddress; 312 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 313 RealOffset; 314 LLVM_DEBUG(dbgs() << "Writing " << format("%p", RealOffset) << " at " 315 << format("%p\n", FinalAddress)); 316 break; 317 } 318 case ELF::R_X86_64_GOTOFF64: { 319 // Compute Value - GOTBase. 320 uint64_t GOTBase = 0; 321 for (const auto &Section : Sections) { 322 if (Section.getName() == ".got") { 323 GOTBase = Section.getLoadAddressWithOffset(0); 324 break; 325 } 326 } 327 assert(GOTBase != 0 && "missing GOT"); 328 int64_t GOTOffset = Value - GOTBase + Addend; 329 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = GOTOffset; 330 break; 331 } 332 } 333 } 334 335 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 336 uint64_t Offset, uint32_t Value, 337 uint32_t Type, int32_t Addend) { 338 switch (Type) { 339 case ELF::R_386_32: { 340 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 341 Value + Addend; 342 break; 343 } 344 // Handle R_386_PLT32 like R_386_PC32 since it should be able to 345 // reach any 32 bit address. 346 case ELF::R_386_PLT32: 347 case ELF::R_386_PC32: { 348 uint32_t FinalAddress = 349 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 350 uint32_t RealOffset = Value + Addend - FinalAddress; 351 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 352 RealOffset; 353 break; 354 } 355 default: 356 // There are other relocation types, but it appears these are the 357 // only ones currently used by the LLVM ELF object writer 358 llvm_unreachable("Relocation type not implemented yet!"); 359 break; 360 } 361 } 362 363 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 364 uint64_t Offset, uint64_t Value, 365 uint32_t Type, int64_t Addend) { 366 uint32_t *TargetPtr = 367 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 368 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 369 // Data should use target endian. Code should always use little endian. 370 bool isBE = Arch == Triple::aarch64_be; 371 372 LLVM_DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 373 << format("%llx", Section.getAddressWithOffset(Offset)) 374 << " FinalAddress: 0x" << format("%llx", FinalAddress) 375 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 376 << format("%x", Type) << " Addend: 0x" 377 << format("%llx", Addend) << "\n"); 378 379 switch (Type) { 380 default: 381 llvm_unreachable("Relocation type not implemented yet!"); 382 break; 383 case ELF::R_AARCH64_ABS16: { 384 uint64_t Result = Value + Addend; 385 assert(static_cast<int64_t>(Result) >= INT16_MIN && Result < UINT16_MAX); 386 write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU)); 387 break; 388 } 389 case ELF::R_AARCH64_ABS32: { 390 uint64_t Result = Value + Addend; 391 assert(static_cast<int64_t>(Result) >= INT32_MIN && Result < UINT32_MAX); 392 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 393 break; 394 } 395 case ELF::R_AARCH64_ABS64: 396 write(isBE, TargetPtr, Value + Addend); 397 break; 398 case ELF::R_AARCH64_PREL32: { 399 uint64_t Result = Value + Addend - FinalAddress; 400 assert(static_cast<int64_t>(Result) >= INT32_MIN && 401 static_cast<int64_t>(Result) <= UINT32_MAX); 402 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 403 break; 404 } 405 case ELF::R_AARCH64_PREL64: 406 write(isBE, TargetPtr, Value + Addend - FinalAddress); 407 break; 408 case ELF::R_AARCH64_CALL26: // fallthrough 409 case ELF::R_AARCH64_JUMP26: { 410 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 411 // calculation. 412 uint64_t BranchImm = Value + Addend - FinalAddress; 413 414 // "Check that -2^27 <= result < 2^27". 415 assert(isInt<28>(BranchImm)); 416 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 417 break; 418 } 419 case ELF::R_AARCH64_MOVW_UABS_G3: 420 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 421 break; 422 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 423 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 424 break; 425 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 426 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 427 break; 428 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 429 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 430 break; 431 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 432 // Operation: Page(S+A) - Page(P) 433 uint64_t Result = 434 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 435 436 // Check that -2^32 <= X < 2^32 437 assert(isInt<33>(Result) && "overflow check failed for relocation"); 438 439 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 440 // from bits 32:12 of X. 441 write32AArch64Addr(TargetPtr, Result >> 12); 442 break; 443 } 444 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 445 // Operation: S + A 446 // Immediate goes in bits 21:10 of LD/ST instruction, taken 447 // from bits 11:0 of X 448 or32AArch64Imm(TargetPtr, Value + Addend); 449 break; 450 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 451 // Operation: S + A 452 // Immediate goes in bits 21:10 of LD/ST instruction, taken 453 // from bits 11:0 of X 454 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 455 break; 456 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 457 // Operation: S + A 458 // Immediate goes in bits 21:10 of LD/ST instruction, taken 459 // from bits 11:1 of X 460 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 461 break; 462 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 463 // Operation: S + A 464 // Immediate goes in bits 21:10 of LD/ST instruction, taken 465 // from bits 11:2 of X 466 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 467 break; 468 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 469 // Operation: S + A 470 // Immediate goes in bits 21:10 of LD/ST instruction, taken 471 // from bits 11:3 of X 472 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 473 break; 474 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 475 // Operation: S + A 476 // Immediate goes in bits 21:10 of LD/ST instruction, taken 477 // from bits 11:4 of X 478 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 479 break; 480 } 481 } 482 483 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 484 uint64_t Offset, uint32_t Value, 485 uint32_t Type, int32_t Addend) { 486 // TODO: Add Thumb relocations. 487 uint32_t *TargetPtr = 488 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 489 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 490 Value += Addend; 491 492 LLVM_DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 493 << Section.getAddressWithOffset(Offset) 494 << " FinalAddress: " << format("%p", FinalAddress) 495 << " Value: " << format("%x", Value) 496 << " Type: " << format("%x", Type) 497 << " Addend: " << format("%x", Addend) << "\n"); 498 499 switch (Type) { 500 default: 501 llvm_unreachable("Not implemented relocation type!"); 502 503 case ELF::R_ARM_NONE: 504 break; 505 // Write a 31bit signed offset 506 case ELF::R_ARM_PREL31: 507 support::ulittle32_t::ref{TargetPtr} = 508 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 509 ((Value - FinalAddress) & ~0x80000000); 510 break; 511 case ELF::R_ARM_TARGET1: 512 case ELF::R_ARM_ABS32: 513 support::ulittle32_t::ref{TargetPtr} = Value; 514 break; 515 // Write first 16 bit of 32 bit value to the mov instruction. 516 // Last 4 bit should be shifted. 517 case ELF::R_ARM_MOVW_ABS_NC: 518 case ELF::R_ARM_MOVT_ABS: 519 if (Type == ELF::R_ARM_MOVW_ABS_NC) 520 Value = Value & 0xFFFF; 521 else if (Type == ELF::R_ARM_MOVT_ABS) 522 Value = (Value >> 16) & 0xFFFF; 523 support::ulittle32_t::ref{TargetPtr} = 524 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 525 (((Value >> 12) & 0xF) << 16); 526 break; 527 // Write 24 bit relative value to the branch instruction. 528 case ELF::R_ARM_PC24: // Fall through. 529 case ELF::R_ARM_CALL: // Fall through. 530 case ELF::R_ARM_JUMP24: 531 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 532 RelValue = (RelValue & 0x03FFFFFC) >> 2; 533 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 534 support::ulittle32_t::ref{TargetPtr} = 535 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 536 break; 537 } 538 } 539 540 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 541 if (Arch == Triple::UnknownArch || 542 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 543 IsMipsO32ABI = false; 544 IsMipsN32ABI = false; 545 IsMipsN64ABI = false; 546 return; 547 } 548 if (auto *E = dyn_cast<ELFObjectFileBase>(&Obj)) { 549 unsigned AbiVariant = E->getPlatformFlags(); 550 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 551 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 552 } 553 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); 554 } 555 556 // Return the .TOC. section and offset. 557 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 558 ObjSectionToIDMap &LocalSections, 559 RelocationValueRef &Rel) { 560 // Set a default SectionID in case we do not find a TOC section below. 561 // This may happen for references to TOC base base (sym@toc, .odp 562 // relocation) without a .toc directive. In this case just use the 563 // first section (which is usually the .odp) since the code won't 564 // reference the .toc base directly. 565 Rel.SymbolName = nullptr; 566 Rel.SectionID = 0; 567 568 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 569 // order. The TOC starts where the first of these sections starts. 570 for (auto &Section: Obj.sections()) { 571 StringRef SectionName; 572 if (auto EC = Section.getName(SectionName)) 573 return errorCodeToError(EC); 574 575 if (SectionName == ".got" 576 || SectionName == ".toc" 577 || SectionName == ".tocbss" 578 || SectionName == ".plt") { 579 if (auto SectionIDOrErr = 580 findOrEmitSection(Obj, Section, false, LocalSections)) 581 Rel.SectionID = *SectionIDOrErr; 582 else 583 return SectionIDOrErr.takeError(); 584 break; 585 } 586 } 587 588 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 589 // thus permitting a full 64 Kbytes segment. 590 Rel.Addend = 0x8000; 591 592 return Error::success(); 593 } 594 595 // Returns the sections and offset associated with the ODP entry referenced 596 // by Symbol. 597 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 598 ObjSectionToIDMap &LocalSections, 599 RelocationValueRef &Rel) { 600 // Get the ELF symbol value (st_value) to compare with Relocation offset in 601 // .opd entries 602 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 603 si != se; ++si) { 604 section_iterator RelSecI = si->getRelocatedSection(); 605 if (RelSecI == Obj.section_end()) 606 continue; 607 608 StringRef RelSectionName; 609 if (auto EC = RelSecI->getName(RelSectionName)) 610 return errorCodeToError(EC); 611 612 if (RelSectionName != ".opd") 613 continue; 614 615 for (elf_relocation_iterator i = si->relocation_begin(), 616 e = si->relocation_end(); 617 i != e;) { 618 // The R_PPC64_ADDR64 relocation indicates the first field 619 // of a .opd entry 620 uint64_t TypeFunc = i->getType(); 621 if (TypeFunc != ELF::R_PPC64_ADDR64) { 622 ++i; 623 continue; 624 } 625 626 uint64_t TargetSymbolOffset = i->getOffset(); 627 symbol_iterator TargetSymbol = i->getSymbol(); 628 int64_t Addend; 629 if (auto AddendOrErr = i->getAddend()) 630 Addend = *AddendOrErr; 631 else 632 return AddendOrErr.takeError(); 633 634 ++i; 635 if (i == e) 636 break; 637 638 // Just check if following relocation is a R_PPC64_TOC 639 uint64_t TypeTOC = i->getType(); 640 if (TypeTOC != ELF::R_PPC64_TOC) 641 continue; 642 643 // Finally compares the Symbol value and the target symbol offset 644 // to check if this .opd entry refers to the symbol the relocation 645 // points to. 646 if (Rel.Addend != (int64_t)TargetSymbolOffset) 647 continue; 648 649 section_iterator TSI = Obj.section_end(); 650 if (auto TSIOrErr = TargetSymbol->getSection()) 651 TSI = *TSIOrErr; 652 else 653 return TSIOrErr.takeError(); 654 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 655 656 bool IsCode = TSI->isText(); 657 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 658 LocalSections)) 659 Rel.SectionID = *SectionIDOrErr; 660 else 661 return SectionIDOrErr.takeError(); 662 Rel.Addend = (intptr_t)Addend; 663 return Error::success(); 664 } 665 } 666 llvm_unreachable("Attempting to get address of ODP entry!"); 667 } 668 669 // Relocation masks following the #lo(value), #hi(value), #ha(value), 670 // #higher(value), #highera(value), #highest(value), and #highesta(value) 671 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 672 // document. 673 674 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 675 676 static inline uint16_t applyPPChi(uint64_t value) { 677 return (value >> 16) & 0xffff; 678 } 679 680 static inline uint16_t applyPPCha (uint64_t value) { 681 return ((value + 0x8000) >> 16) & 0xffff; 682 } 683 684 static inline uint16_t applyPPChigher(uint64_t value) { 685 return (value >> 32) & 0xffff; 686 } 687 688 static inline uint16_t applyPPChighera (uint64_t value) { 689 return ((value + 0x8000) >> 32) & 0xffff; 690 } 691 692 static inline uint16_t applyPPChighest(uint64_t value) { 693 return (value >> 48) & 0xffff; 694 } 695 696 static inline uint16_t applyPPChighesta (uint64_t value) { 697 return ((value + 0x8000) >> 48) & 0xffff; 698 } 699 700 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 701 uint64_t Offset, uint64_t Value, 702 uint32_t Type, int64_t Addend) { 703 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 704 switch (Type) { 705 default: 706 llvm_unreachable("Relocation type not implemented yet!"); 707 break; 708 case ELF::R_PPC_ADDR16_LO: 709 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 710 break; 711 case ELF::R_PPC_ADDR16_HI: 712 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 713 break; 714 case ELF::R_PPC_ADDR16_HA: 715 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 716 break; 717 } 718 } 719 720 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 721 uint64_t Offset, uint64_t Value, 722 uint32_t Type, int64_t Addend) { 723 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 724 switch (Type) { 725 default: 726 llvm_unreachable("Relocation type not implemented yet!"); 727 break; 728 case ELF::R_PPC64_ADDR16: 729 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 730 break; 731 case ELF::R_PPC64_ADDR16_DS: 732 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 733 break; 734 case ELF::R_PPC64_ADDR16_LO: 735 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 736 break; 737 case ELF::R_PPC64_ADDR16_LO_DS: 738 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 739 break; 740 case ELF::R_PPC64_ADDR16_HI: 741 case ELF::R_PPC64_ADDR16_HIGH: 742 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 743 break; 744 case ELF::R_PPC64_ADDR16_HA: 745 case ELF::R_PPC64_ADDR16_HIGHA: 746 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 747 break; 748 case ELF::R_PPC64_ADDR16_HIGHER: 749 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 750 break; 751 case ELF::R_PPC64_ADDR16_HIGHERA: 752 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 753 break; 754 case ELF::R_PPC64_ADDR16_HIGHEST: 755 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 756 break; 757 case ELF::R_PPC64_ADDR16_HIGHESTA: 758 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 759 break; 760 case ELF::R_PPC64_ADDR14: { 761 assert(((Value + Addend) & 3) == 0); 762 // Preserve the AA/LK bits in the branch instruction 763 uint8_t aalk = *(LocalAddress + 3); 764 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 765 } break; 766 case ELF::R_PPC64_REL16_LO: { 767 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 768 uint64_t Delta = Value - FinalAddress + Addend; 769 writeInt16BE(LocalAddress, applyPPClo(Delta)); 770 } break; 771 case ELF::R_PPC64_REL16_HI: { 772 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 773 uint64_t Delta = Value - FinalAddress + Addend; 774 writeInt16BE(LocalAddress, applyPPChi(Delta)); 775 } break; 776 case ELF::R_PPC64_REL16_HA: { 777 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 778 uint64_t Delta = Value - FinalAddress + Addend; 779 writeInt16BE(LocalAddress, applyPPCha(Delta)); 780 } break; 781 case ELF::R_PPC64_ADDR32: { 782 int64_t Result = static_cast<int64_t>(Value + Addend); 783 if (SignExtend64<32>(Result) != Result) 784 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 785 writeInt32BE(LocalAddress, Result); 786 } break; 787 case ELF::R_PPC64_REL24: { 788 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 789 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 790 if (SignExtend64<26>(delta) != delta) 791 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 792 // We preserve bits other than LI field, i.e. PO and AA/LK fields. 793 uint32_t Inst = readBytesUnaligned(LocalAddress, 4); 794 writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC)); 795 } break; 796 case ELF::R_PPC64_REL32: { 797 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 798 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 799 if (SignExtend64<32>(delta) != delta) 800 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 801 writeInt32BE(LocalAddress, delta); 802 } break; 803 case ELF::R_PPC64_REL64: { 804 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 805 uint64_t Delta = Value - FinalAddress + Addend; 806 writeInt64BE(LocalAddress, Delta); 807 } break; 808 case ELF::R_PPC64_ADDR64: 809 writeInt64BE(LocalAddress, Value + Addend); 810 break; 811 } 812 } 813 814 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 815 uint64_t Offset, uint64_t Value, 816 uint32_t Type, int64_t Addend) { 817 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 818 switch (Type) { 819 default: 820 llvm_unreachable("Relocation type not implemented yet!"); 821 break; 822 case ELF::R_390_PC16DBL: 823 case ELF::R_390_PLT16DBL: { 824 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 825 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 826 writeInt16BE(LocalAddress, Delta / 2); 827 break; 828 } 829 case ELF::R_390_PC32DBL: 830 case ELF::R_390_PLT32DBL: { 831 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 832 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 833 writeInt32BE(LocalAddress, Delta / 2); 834 break; 835 } 836 case ELF::R_390_PC16: { 837 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 838 assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); 839 writeInt16BE(LocalAddress, Delta); 840 break; 841 } 842 case ELF::R_390_PC32: { 843 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 844 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 845 writeInt32BE(LocalAddress, Delta); 846 break; 847 } 848 case ELF::R_390_PC64: { 849 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 850 writeInt64BE(LocalAddress, Delta); 851 break; 852 } 853 case ELF::R_390_8: 854 *LocalAddress = (uint8_t)(Value + Addend); 855 break; 856 case ELF::R_390_16: 857 writeInt16BE(LocalAddress, Value + Addend); 858 break; 859 case ELF::R_390_32: 860 writeInt32BE(LocalAddress, Value + Addend); 861 break; 862 case ELF::R_390_64: 863 writeInt64BE(LocalAddress, Value + Addend); 864 break; 865 } 866 } 867 868 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 869 uint64_t Offset, uint64_t Value, 870 uint32_t Type, int64_t Addend) { 871 bool isBE = Arch == Triple::bpfeb; 872 873 switch (Type) { 874 default: 875 llvm_unreachable("Relocation type not implemented yet!"); 876 break; 877 case ELF::R_BPF_NONE: 878 break; 879 case ELF::R_BPF_64_64: { 880 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 881 LLVM_DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 882 << format("%p\n", Section.getAddressWithOffset(Offset))); 883 break; 884 } 885 case ELF::R_BPF_64_32: { 886 Value += Addend; 887 assert(Value <= UINT32_MAX); 888 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 889 LLVM_DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 890 << format("%p\n", Section.getAddressWithOffset(Offset))); 891 break; 892 } 893 } 894 } 895 896 // The target location for the relocation is described by RE.SectionID and 897 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 898 // SectionEntry has three members describing its location. 899 // SectionEntry::Address is the address at which the section has been loaded 900 // into memory in the current (host) process. SectionEntry::LoadAddress is the 901 // address that the section will have in the target process. 902 // SectionEntry::ObjAddress is the address of the bits for this section in the 903 // original emitted object image (also in the current address space). 904 // 905 // Relocations will be applied as if the section were loaded at 906 // SectionEntry::LoadAddress, but they will be applied at an address based 907 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 908 // Target memory contents if they are required for value calculations. 909 // 910 // The Value parameter here is the load address of the symbol for the 911 // relocation to be applied. For relocations which refer to symbols in the 912 // current object Value will be the LoadAddress of the section in which 913 // the symbol resides (RE.Addend provides additional information about the 914 // symbol location). For external symbols, Value will be the address of the 915 // symbol in the target address space. 916 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 917 uint64_t Value) { 918 const SectionEntry &Section = Sections[RE.SectionID]; 919 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 920 RE.SymOffset, RE.SectionID); 921 } 922 923 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 924 uint64_t Offset, uint64_t Value, 925 uint32_t Type, int64_t Addend, 926 uint64_t SymOffset, SID SectionID) { 927 switch (Arch) { 928 case Triple::x86_64: 929 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 930 break; 931 case Triple::x86: 932 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 933 (uint32_t)(Addend & 0xffffffffL)); 934 break; 935 case Triple::aarch64: 936 case Triple::aarch64_be: 937 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 938 break; 939 case Triple::arm: // Fall through. 940 case Triple::armeb: 941 case Triple::thumb: 942 case Triple::thumbeb: 943 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 944 (uint32_t)(Addend & 0xffffffffL)); 945 break; 946 case Triple::ppc: 947 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 948 break; 949 case Triple::ppc64: // Fall through. 950 case Triple::ppc64le: 951 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 952 break; 953 case Triple::systemz: 954 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 955 break; 956 case Triple::bpfel: 957 case Triple::bpfeb: 958 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 959 break; 960 default: 961 llvm_unreachable("Unsupported CPU type!"); 962 } 963 } 964 965 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 966 return (void *)(Sections[SectionID].getObjAddress() + Offset); 967 } 968 969 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 970 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 971 if (Value.SymbolName) 972 addRelocationForSymbol(RE, Value.SymbolName); 973 else 974 addRelocationForSection(RE, Value.SectionID); 975 } 976 977 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 978 bool IsLocal) const { 979 switch (RelType) { 980 case ELF::R_MICROMIPS_GOT16: 981 if (IsLocal) 982 return ELF::R_MICROMIPS_LO16; 983 break; 984 case ELF::R_MICROMIPS_HI16: 985 return ELF::R_MICROMIPS_LO16; 986 case ELF::R_MIPS_GOT16: 987 if (IsLocal) 988 return ELF::R_MIPS_LO16; 989 break; 990 case ELF::R_MIPS_HI16: 991 return ELF::R_MIPS_LO16; 992 case ELF::R_MIPS_PCHI16: 993 return ELF::R_MIPS_PCLO16; 994 default: 995 break; 996 } 997 return ELF::R_MIPS_NONE; 998 } 999 1000 // Sometimes we don't need to create thunk for a branch. 1001 // This typically happens when branch target is located 1002 // in the same object file. In such case target is either 1003 // a weak symbol or symbol in a different executable section. 1004 // This function checks if branch target is located in the 1005 // same object file and if distance between source and target 1006 // fits R_AARCH64_CALL26 relocation. If both conditions are 1007 // met, it emits direct jump to the target and returns true. 1008 // Otherwise false is returned and thunk is created. 1009 bool RuntimeDyldELF::resolveAArch64ShortBranch( 1010 unsigned SectionID, relocation_iterator RelI, 1011 const RelocationValueRef &Value) { 1012 uint64_t Address; 1013 if (Value.SymbolName) { 1014 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 1015 1016 // Don't create direct branch for external symbols. 1017 if (Loc == GlobalSymbolTable.end()) 1018 return false; 1019 1020 const auto &SymInfo = Loc->second; 1021 Address = 1022 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 1023 SymInfo.getOffset())); 1024 } else { 1025 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 1026 } 1027 uint64_t Offset = RelI->getOffset(); 1028 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 1029 1030 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 1031 // If distance between source and target is out of range then we should 1032 // create thunk. 1033 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 1034 return false; 1035 1036 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 1037 Value.Addend); 1038 1039 return true; 1040 } 1041 1042 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 1043 const RelocationValueRef &Value, 1044 relocation_iterator RelI, 1045 StubMap &Stubs) { 1046 1047 LLVM_DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1048 SectionEntry &Section = Sections[SectionID]; 1049 1050 uint64_t Offset = RelI->getOffset(); 1051 unsigned RelType = RelI->getType(); 1052 // Look for an existing stub. 1053 StubMap::const_iterator i = Stubs.find(Value); 1054 if (i != Stubs.end()) { 1055 resolveRelocation(Section, Offset, 1056 (uint64_t)Section.getAddressWithOffset(i->second), 1057 RelType, 0); 1058 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1059 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1060 // Create a new stub function. 1061 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1062 Stubs[Value] = Section.getStubOffset(); 1063 uint8_t *StubTargetAddr = createStubFunction( 1064 Section.getAddressWithOffset(Section.getStubOffset())); 1065 1066 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1067 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1068 RelocationEntry REmovk_g2(SectionID, 1069 StubTargetAddr - Section.getAddress() + 4, 1070 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1071 RelocationEntry REmovk_g1(SectionID, 1072 StubTargetAddr - Section.getAddress() + 8, 1073 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1074 RelocationEntry REmovk_g0(SectionID, 1075 StubTargetAddr - Section.getAddress() + 12, 1076 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1077 1078 if (Value.SymbolName) { 1079 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1080 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1081 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1082 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1083 } else { 1084 addRelocationForSection(REmovz_g3, Value.SectionID); 1085 addRelocationForSection(REmovk_g2, Value.SectionID); 1086 addRelocationForSection(REmovk_g1, Value.SectionID); 1087 addRelocationForSection(REmovk_g0, Value.SectionID); 1088 } 1089 resolveRelocation(Section, Offset, 1090 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1091 Section.getStubOffset())), 1092 RelType, 0); 1093 Section.advanceStubOffset(getMaxStubSize()); 1094 } 1095 } 1096 1097 Expected<relocation_iterator> 1098 RuntimeDyldELF::processRelocationRef( 1099 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1100 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1101 const auto &Obj = cast<ELFObjectFileBase>(O); 1102 uint64_t RelType = RelI->getType(); 1103 int64_t Addend = 0; 1104 if (Expected<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend()) 1105 Addend = *AddendOrErr; 1106 else 1107 consumeError(AddendOrErr.takeError()); 1108 elf_symbol_iterator Symbol = RelI->getSymbol(); 1109 1110 // Obtain the symbol name which is referenced in the relocation 1111 StringRef TargetName; 1112 if (Symbol != Obj.symbol_end()) { 1113 if (auto TargetNameOrErr = Symbol->getName()) 1114 TargetName = *TargetNameOrErr; 1115 else 1116 return TargetNameOrErr.takeError(); 1117 } 1118 LLVM_DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1119 << " TargetName: " << TargetName << "\n"); 1120 RelocationValueRef Value; 1121 // First search for the symbol in the local symbol table 1122 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1123 1124 // Search for the symbol in the global symbol table 1125 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1126 if (Symbol != Obj.symbol_end()) { 1127 gsi = GlobalSymbolTable.find(TargetName.data()); 1128 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1129 if (!SymTypeOrErr) { 1130 std::string Buf; 1131 raw_string_ostream OS(Buf); 1132 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS); 1133 OS.flush(); 1134 report_fatal_error(Buf); 1135 } 1136 SymType = *SymTypeOrErr; 1137 } 1138 if (gsi != GlobalSymbolTable.end()) { 1139 const auto &SymInfo = gsi->second; 1140 Value.SectionID = SymInfo.getSectionID(); 1141 Value.Offset = SymInfo.getOffset(); 1142 Value.Addend = SymInfo.getOffset() + Addend; 1143 } else { 1144 switch (SymType) { 1145 case SymbolRef::ST_Debug: { 1146 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1147 // and can be changed by another developers. Maybe best way is add 1148 // a new symbol type ST_Section to SymbolRef and use it. 1149 auto SectionOrErr = Symbol->getSection(); 1150 if (!SectionOrErr) { 1151 std::string Buf; 1152 raw_string_ostream OS(Buf); 1153 logAllUnhandledErrors(SectionOrErr.takeError(), OS); 1154 OS.flush(); 1155 report_fatal_error(Buf); 1156 } 1157 section_iterator si = *SectionOrErr; 1158 if (si == Obj.section_end()) 1159 llvm_unreachable("Symbol section not found, bad object file format!"); 1160 LLVM_DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1161 bool isCode = si->isText(); 1162 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1163 ObjSectionToID)) 1164 Value.SectionID = *SectionIDOrErr; 1165 else 1166 return SectionIDOrErr.takeError(); 1167 Value.Addend = Addend; 1168 break; 1169 } 1170 case SymbolRef::ST_Data: 1171 case SymbolRef::ST_Function: 1172 case SymbolRef::ST_Unknown: { 1173 Value.SymbolName = TargetName.data(); 1174 Value.Addend = Addend; 1175 1176 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1177 // will manifest here as a NULL symbol name. 1178 // We can set this as a valid (but empty) symbol name, and rely 1179 // on addRelocationForSymbol to handle this. 1180 if (!Value.SymbolName) 1181 Value.SymbolName = ""; 1182 break; 1183 } 1184 default: 1185 llvm_unreachable("Unresolved symbol type!"); 1186 break; 1187 } 1188 } 1189 1190 uint64_t Offset = RelI->getOffset(); 1191 1192 LLVM_DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1193 << "\n"); 1194 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1195 if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { 1196 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1197 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1198 // Craete new GOT entry or find existing one. If GOT entry is 1199 // to be created, then we also emit ABS64 relocation for it. 1200 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1201 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1202 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1203 1204 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1205 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1206 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1207 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1208 } else { 1209 processSimpleRelocation(SectionID, Offset, RelType, Value); 1210 } 1211 } else if (Arch == Triple::arm) { 1212 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1213 RelType == ELF::R_ARM_JUMP24) { 1214 // This is an ARM branch relocation, need to use a stub function. 1215 LLVM_DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1216 SectionEntry &Section = Sections[SectionID]; 1217 1218 // Look for an existing stub. 1219 StubMap::const_iterator i = Stubs.find(Value); 1220 if (i != Stubs.end()) { 1221 resolveRelocation( 1222 Section, Offset, 1223 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1224 RelType, 0); 1225 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1226 } else { 1227 // Create a new stub function. 1228 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1229 Stubs[Value] = Section.getStubOffset(); 1230 uint8_t *StubTargetAddr = createStubFunction( 1231 Section.getAddressWithOffset(Section.getStubOffset())); 1232 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1233 ELF::R_ARM_ABS32, Value.Addend); 1234 if (Value.SymbolName) 1235 addRelocationForSymbol(RE, Value.SymbolName); 1236 else 1237 addRelocationForSection(RE, Value.SectionID); 1238 1239 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1240 Section.getAddressWithOffset( 1241 Section.getStubOffset())), 1242 RelType, 0); 1243 Section.advanceStubOffset(getMaxStubSize()); 1244 } 1245 } else { 1246 uint32_t *Placeholder = 1247 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1248 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1249 RelType == ELF::R_ARM_ABS32) { 1250 Value.Addend += *Placeholder; 1251 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1252 // See ELF for ARM documentation 1253 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1254 } 1255 processSimpleRelocation(SectionID, Offset, RelType, Value); 1256 } 1257 } else if (IsMipsO32ABI) { 1258 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1259 computePlaceholderAddress(SectionID, Offset)); 1260 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1261 if (RelType == ELF::R_MIPS_26) { 1262 // This is an Mips branch relocation, need to use a stub function. 1263 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1264 SectionEntry &Section = Sections[SectionID]; 1265 1266 // Extract the addend from the instruction. 1267 // We shift up by two since the Value will be down shifted again 1268 // when applying the relocation. 1269 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1270 1271 Value.Addend += Addend; 1272 1273 // Look up for existing stub. 1274 StubMap::const_iterator i = Stubs.find(Value); 1275 if (i != Stubs.end()) { 1276 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1277 addRelocationForSection(RE, SectionID); 1278 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1279 } else { 1280 // Create a new stub function. 1281 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1282 Stubs[Value] = Section.getStubOffset(); 1283 1284 unsigned AbiVariant = Obj.getPlatformFlags(); 1285 1286 uint8_t *StubTargetAddr = createStubFunction( 1287 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1288 1289 // Creating Hi and Lo relocations for the filled stub instructions. 1290 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1291 ELF::R_MIPS_HI16, Value.Addend); 1292 RelocationEntry RELo(SectionID, 1293 StubTargetAddr - Section.getAddress() + 4, 1294 ELF::R_MIPS_LO16, Value.Addend); 1295 1296 if (Value.SymbolName) { 1297 addRelocationForSymbol(REHi, Value.SymbolName); 1298 addRelocationForSymbol(RELo, Value.SymbolName); 1299 } else { 1300 addRelocationForSection(REHi, Value.SectionID); 1301 addRelocationForSection(RELo, Value.SectionID); 1302 } 1303 1304 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1305 addRelocationForSection(RE, SectionID); 1306 Section.advanceStubOffset(getMaxStubSize()); 1307 } 1308 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1309 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1310 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1311 PendingRelocs.push_back(std::make_pair(Value, RE)); 1312 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1313 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1314 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1315 const RelocationValueRef &MatchingValue = I->first; 1316 RelocationEntry &Reloc = I->second; 1317 if (MatchingValue == Value && 1318 RelType == getMatchingLoRelocation(Reloc.RelType) && 1319 SectionID == Reloc.SectionID) { 1320 Reloc.Addend += Addend; 1321 if (Value.SymbolName) 1322 addRelocationForSymbol(Reloc, Value.SymbolName); 1323 else 1324 addRelocationForSection(Reloc, Value.SectionID); 1325 I = PendingRelocs.erase(I); 1326 } else 1327 ++I; 1328 } 1329 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1330 if (Value.SymbolName) 1331 addRelocationForSymbol(RE, Value.SymbolName); 1332 else 1333 addRelocationForSection(RE, Value.SectionID); 1334 } else { 1335 if (RelType == ELF::R_MIPS_32) 1336 Value.Addend += Opcode; 1337 else if (RelType == ELF::R_MIPS_PC16) 1338 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1339 else if (RelType == ELF::R_MIPS_PC19_S2) 1340 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1341 else if (RelType == ELF::R_MIPS_PC21_S2) 1342 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1343 else if (RelType == ELF::R_MIPS_PC26_S2) 1344 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1345 processSimpleRelocation(SectionID, Offset, RelType, Value); 1346 } 1347 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1348 uint32_t r_type = RelType & 0xff; 1349 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1350 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1351 || r_type == ELF::R_MIPS_GOT_DISP) { 1352 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1353 if (i != GOTSymbolOffsets.end()) 1354 RE.SymOffset = i->second; 1355 else { 1356 RE.SymOffset = allocateGOTEntries(1); 1357 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1358 } 1359 if (Value.SymbolName) 1360 addRelocationForSymbol(RE, Value.SymbolName); 1361 else 1362 addRelocationForSection(RE, Value.SectionID); 1363 } else if (RelType == ELF::R_MIPS_26) { 1364 // This is an Mips branch relocation, need to use a stub function. 1365 LLVM_DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1366 SectionEntry &Section = Sections[SectionID]; 1367 1368 // Look up for existing stub. 1369 StubMap::const_iterator i = Stubs.find(Value); 1370 if (i != Stubs.end()) { 1371 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1372 addRelocationForSection(RE, SectionID); 1373 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1374 } else { 1375 // Create a new stub function. 1376 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1377 Stubs[Value] = Section.getStubOffset(); 1378 1379 unsigned AbiVariant = Obj.getPlatformFlags(); 1380 1381 uint8_t *StubTargetAddr = createStubFunction( 1382 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1383 1384 if (IsMipsN32ABI) { 1385 // Creating Hi and Lo relocations for the filled stub instructions. 1386 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1387 ELF::R_MIPS_HI16, Value.Addend); 1388 RelocationEntry RELo(SectionID, 1389 StubTargetAddr - Section.getAddress() + 4, 1390 ELF::R_MIPS_LO16, Value.Addend); 1391 if (Value.SymbolName) { 1392 addRelocationForSymbol(REHi, Value.SymbolName); 1393 addRelocationForSymbol(RELo, Value.SymbolName); 1394 } else { 1395 addRelocationForSection(REHi, Value.SectionID); 1396 addRelocationForSection(RELo, Value.SectionID); 1397 } 1398 } else { 1399 // Creating Highest, Higher, Hi and Lo relocations for the filled stub 1400 // instructions. 1401 RelocationEntry REHighest(SectionID, 1402 StubTargetAddr - Section.getAddress(), 1403 ELF::R_MIPS_HIGHEST, Value.Addend); 1404 RelocationEntry REHigher(SectionID, 1405 StubTargetAddr - Section.getAddress() + 4, 1406 ELF::R_MIPS_HIGHER, Value.Addend); 1407 RelocationEntry REHi(SectionID, 1408 StubTargetAddr - Section.getAddress() + 12, 1409 ELF::R_MIPS_HI16, Value.Addend); 1410 RelocationEntry RELo(SectionID, 1411 StubTargetAddr - Section.getAddress() + 20, 1412 ELF::R_MIPS_LO16, Value.Addend); 1413 if (Value.SymbolName) { 1414 addRelocationForSymbol(REHighest, Value.SymbolName); 1415 addRelocationForSymbol(REHigher, Value.SymbolName); 1416 addRelocationForSymbol(REHi, Value.SymbolName); 1417 addRelocationForSymbol(RELo, Value.SymbolName); 1418 } else { 1419 addRelocationForSection(REHighest, Value.SectionID); 1420 addRelocationForSection(REHigher, Value.SectionID); 1421 addRelocationForSection(REHi, Value.SectionID); 1422 addRelocationForSection(RELo, Value.SectionID); 1423 } 1424 } 1425 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1426 addRelocationForSection(RE, SectionID); 1427 Section.advanceStubOffset(getMaxStubSize()); 1428 } 1429 } else { 1430 processSimpleRelocation(SectionID, Offset, RelType, Value); 1431 } 1432 1433 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1434 if (RelType == ELF::R_PPC64_REL24) { 1435 // Determine ABI variant in use for this object. 1436 unsigned AbiVariant = Obj.getPlatformFlags(); 1437 AbiVariant &= ELF::EF_PPC64_ABI; 1438 // A PPC branch relocation will need a stub function if the target is 1439 // an external symbol (either Value.SymbolName is set, or SymType is 1440 // Symbol::ST_Unknown) or if the target address is not within the 1441 // signed 24-bits branch address. 1442 SectionEntry &Section = Sections[SectionID]; 1443 uint8_t *Target = Section.getAddressWithOffset(Offset); 1444 bool RangeOverflow = false; 1445 bool IsExtern = Value.SymbolName || SymType == SymbolRef::ST_Unknown; 1446 if (!IsExtern) { 1447 if (AbiVariant != 2) { 1448 // In the ELFv1 ABI, a function call may point to the .opd entry, 1449 // so the final symbol value is calculated based on the relocation 1450 // values in the .opd section. 1451 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1452 return std::move(Err); 1453 } else { 1454 // In the ELFv2 ABI, a function symbol may provide a local entry 1455 // point, which must be used for direct calls. 1456 if (Value.SectionID == SectionID){ 1457 uint8_t SymOther = Symbol->getOther(); 1458 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1459 } 1460 } 1461 uint8_t *RelocTarget = 1462 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1463 int64_t delta = static_cast<int64_t>(Target - RelocTarget); 1464 // If it is within 26-bits branch range, just set the branch target 1465 if (SignExtend64<26>(delta) != delta) { 1466 RangeOverflow = true; 1467 } else if ((AbiVariant != 2) || 1468 (AbiVariant == 2 && Value.SectionID == SectionID)) { 1469 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1470 addRelocationForSection(RE, Value.SectionID); 1471 } 1472 } 1473 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID) || 1474 RangeOverflow) { 1475 // It is an external symbol (either Value.SymbolName is set, or 1476 // SymType is SymbolRef::ST_Unknown) or out of range. 1477 StubMap::const_iterator i = Stubs.find(Value); 1478 if (i != Stubs.end()) { 1479 // Symbol function stub already created, just relocate to it 1480 resolveRelocation(Section, Offset, 1481 reinterpret_cast<uint64_t>( 1482 Section.getAddressWithOffset(i->second)), 1483 RelType, 0); 1484 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1485 } else { 1486 // Create a new stub function. 1487 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1488 Stubs[Value] = Section.getStubOffset(); 1489 uint8_t *StubTargetAddr = createStubFunction( 1490 Section.getAddressWithOffset(Section.getStubOffset()), 1491 AbiVariant); 1492 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1493 ELF::R_PPC64_ADDR64, Value.Addend); 1494 1495 // Generates the 64-bits address loads as exemplified in section 1496 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1497 // apply to the low part of the instructions, so we have to update 1498 // the offset according to the target endianness. 1499 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1500 if (!IsTargetLittleEndian) 1501 StubRelocOffset += 2; 1502 1503 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1504 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1505 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1506 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1507 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1508 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1509 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1510 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1511 1512 if (Value.SymbolName) { 1513 addRelocationForSymbol(REhst, Value.SymbolName); 1514 addRelocationForSymbol(REhr, Value.SymbolName); 1515 addRelocationForSymbol(REh, Value.SymbolName); 1516 addRelocationForSymbol(REl, Value.SymbolName); 1517 } else { 1518 addRelocationForSection(REhst, Value.SectionID); 1519 addRelocationForSection(REhr, Value.SectionID); 1520 addRelocationForSection(REh, Value.SectionID); 1521 addRelocationForSection(REl, Value.SectionID); 1522 } 1523 1524 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1525 Section.getAddressWithOffset( 1526 Section.getStubOffset())), 1527 RelType, 0); 1528 Section.advanceStubOffset(getMaxStubSize()); 1529 } 1530 if (IsExtern || (AbiVariant == 2 && Value.SectionID != SectionID)) { 1531 // Restore the TOC for external calls 1532 if (AbiVariant == 2) 1533 writeInt32BE(Target + 4, 0xE8410018); // ld r2,24(r1) 1534 else 1535 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1536 } 1537 } 1538 } else if (RelType == ELF::R_PPC64_TOC16 || 1539 RelType == ELF::R_PPC64_TOC16_DS || 1540 RelType == ELF::R_PPC64_TOC16_LO || 1541 RelType == ELF::R_PPC64_TOC16_LO_DS || 1542 RelType == ELF::R_PPC64_TOC16_HI || 1543 RelType == ELF::R_PPC64_TOC16_HA) { 1544 // These relocations are supposed to subtract the TOC address from 1545 // the final value. This does not fit cleanly into the RuntimeDyld 1546 // scheme, since there may be *two* sections involved in determining 1547 // the relocation value (the section of the symbol referred to by the 1548 // relocation, and the TOC section associated with the current module). 1549 // 1550 // Fortunately, these relocations are currently only ever generated 1551 // referring to symbols that themselves reside in the TOC, which means 1552 // that the two sections are actually the same. Thus they cancel out 1553 // and we can immediately resolve the relocation right now. 1554 switch (RelType) { 1555 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1556 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1557 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1558 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1559 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1560 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1561 default: llvm_unreachable("Wrong relocation type."); 1562 } 1563 1564 RelocationValueRef TOCValue; 1565 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1566 return std::move(Err); 1567 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1568 llvm_unreachable("Unsupported TOC relocation."); 1569 Value.Addend -= TOCValue.Addend; 1570 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1571 } else { 1572 // There are two ways to refer to the TOC address directly: either 1573 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1574 // ignored), or via any relocation that refers to the magic ".TOC." 1575 // symbols (in which case the addend is respected). 1576 if (RelType == ELF::R_PPC64_TOC) { 1577 RelType = ELF::R_PPC64_ADDR64; 1578 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1579 return std::move(Err); 1580 } else if (TargetName == ".TOC.") { 1581 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1582 return std::move(Err); 1583 Value.Addend += Addend; 1584 } 1585 1586 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1587 1588 if (Value.SymbolName) 1589 addRelocationForSymbol(RE, Value.SymbolName); 1590 else 1591 addRelocationForSection(RE, Value.SectionID); 1592 } 1593 } else if (Arch == Triple::systemz && 1594 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1595 // Create function stubs for both PLT and GOT references, regardless of 1596 // whether the GOT reference is to data or code. The stub contains the 1597 // full address of the symbol, as needed by GOT references, and the 1598 // executable part only adds an overhead of 8 bytes. 1599 // 1600 // We could try to conserve space by allocating the code and data 1601 // parts of the stub separately. However, as things stand, we allocate 1602 // a stub for every relocation, so using a GOT in JIT code should be 1603 // no less space efficient than using an explicit constant pool. 1604 LLVM_DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1605 SectionEntry &Section = Sections[SectionID]; 1606 1607 // Look for an existing stub. 1608 StubMap::const_iterator i = Stubs.find(Value); 1609 uintptr_t StubAddress; 1610 if (i != Stubs.end()) { 1611 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1612 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1613 } else { 1614 // Create a new stub function. 1615 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1616 1617 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1618 uintptr_t StubAlignment = getStubAlignment(); 1619 StubAddress = 1620 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1621 -StubAlignment; 1622 unsigned StubOffset = StubAddress - BaseAddress; 1623 1624 Stubs[Value] = StubOffset; 1625 createStubFunction((uint8_t *)StubAddress); 1626 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1627 Value.Offset); 1628 if (Value.SymbolName) 1629 addRelocationForSymbol(RE, Value.SymbolName); 1630 else 1631 addRelocationForSection(RE, Value.SectionID); 1632 Section.advanceStubOffset(getMaxStubSize()); 1633 } 1634 1635 if (RelType == ELF::R_390_GOTENT) 1636 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1637 Addend); 1638 else 1639 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1640 } else if (Arch == Triple::x86_64) { 1641 if (RelType == ELF::R_X86_64_PLT32) { 1642 // The way the PLT relocations normally work is that the linker allocates 1643 // the 1644 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1645 // entry will then jump to an address provided by the GOT. On first call, 1646 // the 1647 // GOT address will point back into PLT code that resolves the symbol. After 1648 // the first call, the GOT entry points to the actual function. 1649 // 1650 // For local functions we're ignoring all of that here and just replacing 1651 // the PLT32 relocation type with PC32, which will translate the relocation 1652 // into a PC-relative call directly to the function. For external symbols we 1653 // can't be sure the function will be within 2^32 bytes of the call site, so 1654 // we need to create a stub, which calls into the GOT. This case is 1655 // equivalent to the usual PLT implementation except that we use the stub 1656 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1657 // rather than allocating a PLT section. 1658 if (Value.SymbolName) { 1659 // This is a call to an external function. 1660 // Look for an existing stub. 1661 SectionEntry &Section = Sections[SectionID]; 1662 StubMap::const_iterator i = Stubs.find(Value); 1663 uintptr_t StubAddress; 1664 if (i != Stubs.end()) { 1665 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1666 LLVM_DEBUG(dbgs() << " Stub function found\n"); 1667 } else { 1668 // Create a new stub function (equivalent to a PLT entry). 1669 LLVM_DEBUG(dbgs() << " Create a new stub function\n"); 1670 1671 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1672 uintptr_t StubAlignment = getStubAlignment(); 1673 StubAddress = 1674 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1675 -StubAlignment; 1676 unsigned StubOffset = StubAddress - BaseAddress; 1677 Stubs[Value] = StubOffset; 1678 createStubFunction((uint8_t *)StubAddress); 1679 1680 // Bump our stub offset counter 1681 Section.advanceStubOffset(getMaxStubSize()); 1682 1683 // Allocate a GOT Entry 1684 uint64_t GOTOffset = allocateGOTEntries(1); 1685 1686 // The load of the GOT address has an addend of -4 1687 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1688 ELF::R_X86_64_PC32); 1689 1690 // Fill in the value of the symbol we're targeting into the GOT 1691 addRelocationForSymbol( 1692 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1693 Value.SymbolName); 1694 } 1695 1696 // Make the target call a call into the stub table. 1697 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1698 Addend); 1699 } else { 1700 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1701 Value.Offset); 1702 addRelocationForSection(RE, Value.SectionID); 1703 } 1704 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1705 RelType == ELF::R_X86_64_GOTPCRELX || 1706 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1707 uint64_t GOTOffset = allocateGOTEntries(1); 1708 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1709 ELF::R_X86_64_PC32); 1710 1711 // Fill in the value of the symbol we're targeting into the GOT 1712 RelocationEntry RE = 1713 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1714 if (Value.SymbolName) 1715 addRelocationForSymbol(RE, Value.SymbolName); 1716 else 1717 addRelocationForSection(RE, Value.SectionID); 1718 } else if (RelType == ELF::R_X86_64_GOT64) { 1719 // Fill in a 64-bit GOT offset. 1720 uint64_t GOTOffset = allocateGOTEntries(1); 1721 resolveRelocation(Sections[SectionID], Offset, GOTOffset, 1722 ELF::R_X86_64_64, 0); 1723 1724 // Fill in the value of the symbol we're targeting into the GOT 1725 RelocationEntry RE = 1726 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1727 if (Value.SymbolName) 1728 addRelocationForSymbol(RE, Value.SymbolName); 1729 else 1730 addRelocationForSection(RE, Value.SectionID); 1731 } else if (RelType == ELF::R_X86_64_GOTPC64) { 1732 // Materialize the address of the base of the GOT relative to the PC. 1733 // This doesn't create a GOT entry, but it does mean we need a GOT 1734 // section. 1735 (void)allocateGOTEntries(0); 1736 resolveGOTOffsetRelocation(SectionID, Offset, Addend, ELF::R_X86_64_PC64); 1737 } else if (RelType == ELF::R_X86_64_GOTOFF64) { 1738 // GOTOFF relocations ultimately require a section difference relocation. 1739 (void)allocateGOTEntries(0); 1740 processSimpleRelocation(SectionID, Offset, RelType, Value); 1741 } else if (RelType == ELF::R_X86_64_PC32) { 1742 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1743 processSimpleRelocation(SectionID, Offset, RelType, Value); 1744 } else if (RelType == ELF::R_X86_64_PC64) { 1745 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1746 processSimpleRelocation(SectionID, Offset, RelType, Value); 1747 } else { 1748 processSimpleRelocation(SectionID, Offset, RelType, Value); 1749 } 1750 } else { 1751 if (Arch == Triple::x86) { 1752 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1753 } 1754 processSimpleRelocation(SectionID, Offset, RelType, Value); 1755 } 1756 return ++RelI; 1757 } 1758 1759 size_t RuntimeDyldELF::getGOTEntrySize() { 1760 // We don't use the GOT in all of these cases, but it's essentially free 1761 // to put them all here. 1762 size_t Result = 0; 1763 switch (Arch) { 1764 case Triple::x86_64: 1765 case Triple::aarch64: 1766 case Triple::aarch64_be: 1767 case Triple::ppc64: 1768 case Triple::ppc64le: 1769 case Triple::systemz: 1770 Result = sizeof(uint64_t); 1771 break; 1772 case Triple::x86: 1773 case Triple::arm: 1774 case Triple::thumb: 1775 Result = sizeof(uint32_t); 1776 break; 1777 case Triple::mips: 1778 case Triple::mipsel: 1779 case Triple::mips64: 1780 case Triple::mips64el: 1781 if (IsMipsO32ABI || IsMipsN32ABI) 1782 Result = sizeof(uint32_t); 1783 else if (IsMipsN64ABI) 1784 Result = sizeof(uint64_t); 1785 else 1786 llvm_unreachable("Mips ABI not handled"); 1787 break; 1788 default: 1789 llvm_unreachable("Unsupported CPU type!"); 1790 } 1791 return Result; 1792 } 1793 1794 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 1795 if (GOTSectionID == 0) { 1796 GOTSectionID = Sections.size(); 1797 // Reserve a section id. We'll allocate the section later 1798 // once we know the total size 1799 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1800 } 1801 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1802 CurrentGOTIndex += no; 1803 return StartOffset; 1804 } 1805 1806 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 1807 unsigned GOTRelType) { 1808 auto E = GOTOffsetMap.insert({Value, 0}); 1809 if (E.second) { 1810 uint64_t GOTOffset = allocateGOTEntries(1); 1811 1812 // Create relocation for newly created GOT entry 1813 RelocationEntry RE = 1814 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 1815 if (Value.SymbolName) 1816 addRelocationForSymbol(RE, Value.SymbolName); 1817 else 1818 addRelocationForSection(RE, Value.SectionID); 1819 1820 E.first->second = GOTOffset; 1821 } 1822 1823 return E.first->second; 1824 } 1825 1826 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 1827 uint64_t Offset, 1828 uint64_t GOTOffset, 1829 uint32_t Type) { 1830 // Fill in the relative address of the GOT Entry into the stub 1831 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 1832 addRelocationForSection(GOTRE, GOTSectionID); 1833 } 1834 1835 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 1836 uint64_t SymbolOffset, 1837 uint32_t Type) { 1838 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1839 } 1840 1841 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1842 ObjSectionToIDMap &SectionMap) { 1843 if (IsMipsO32ABI) 1844 if (!PendingRelocs.empty()) 1845 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1846 1847 // If necessary, allocate the global offset table 1848 if (GOTSectionID != 0) { 1849 // Allocate memory for the section 1850 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1851 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1852 GOTSectionID, ".got", false); 1853 if (!Addr) 1854 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1855 1856 Sections[GOTSectionID] = 1857 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1858 1859 // For now, initialize all GOT entries to zero. We'll fill them in as 1860 // needed when GOT-based relocations are applied. 1861 memset(Addr, 0, TotalSize); 1862 if (IsMipsN32ABI || IsMipsN64ABI) { 1863 // To correctly resolve Mips GOT relocations, we need a mapping from 1864 // object's sections to GOTs. 1865 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1866 SI != SE; ++SI) { 1867 if (SI->relocation_begin() != SI->relocation_end()) { 1868 section_iterator RelocatedSection = SI->getRelocatedSection(); 1869 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1870 assert (i != SectionMap.end()); 1871 SectionToGOTMap[i->second] = GOTSectionID; 1872 } 1873 } 1874 GOTSymbolOffsets.clear(); 1875 } 1876 } 1877 1878 // Look for and record the EH frame section. 1879 ObjSectionToIDMap::iterator i, e; 1880 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1881 const SectionRef &Section = i->first; 1882 StringRef Name; 1883 Section.getName(Name); 1884 if (Name == ".eh_frame") { 1885 UnregisteredEHFrameSections.push_back(i->second); 1886 break; 1887 } 1888 } 1889 1890 GOTSectionID = 0; 1891 CurrentGOTIndex = 0; 1892 1893 return Error::success(); 1894 } 1895 1896 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1897 return Obj.isELF(); 1898 } 1899 1900 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 1901 unsigned RelTy = R.getType(); 1902 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 1903 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 1904 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 1905 1906 if (Arch == Triple::x86_64) 1907 return RelTy == ELF::R_X86_64_GOTPCREL || 1908 RelTy == ELF::R_X86_64_GOTPCRELX || 1909 RelTy == ELF::R_X86_64_GOT64 || 1910 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 1911 return false; 1912 } 1913 1914 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1915 if (Arch != Triple::x86_64) 1916 return true; // Conservative answer 1917 1918 switch (R.getType()) { 1919 default: 1920 return true; // Conservative answer 1921 1922 1923 case ELF::R_X86_64_GOTPCREL: 1924 case ELF::R_X86_64_GOTPCRELX: 1925 case ELF::R_X86_64_REX_GOTPCRELX: 1926 case ELF::R_X86_64_GOTPC64: 1927 case ELF::R_X86_64_GOT64: 1928 case ELF::R_X86_64_GOTOFF64: 1929 case ELF::R_X86_64_PC32: 1930 case ELF::R_X86_64_PC64: 1931 case ELF::R_X86_64_64: 1932 // We know that these reloation types won't need a stub function. This list 1933 // can be extended as needed. 1934 return false; 1935 } 1936 } 1937 1938 } // namespace llvm 1939