1 //===-- RuntimeDyldELF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Implementation of ELF support for the MC-JIT runtime dynamic linker. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "RuntimeDyldELF.h" 15 #include "RuntimeDyldCheckerImpl.h" 16 #include "Targets/RuntimeDyldELFMips.h" 17 #include "llvm/ADT/IntervalMap.h" 18 #include "llvm/ADT/STLExtras.h" 19 #include "llvm/ADT/StringRef.h" 20 #include "llvm/ADT/Triple.h" 21 #include "llvm/MC/MCStreamer.h" 22 #include "llvm/Object/ELFObjectFile.h" 23 #include "llvm/Object/ObjectFile.h" 24 #include "llvm/Support/ELF.h" 25 #include "llvm/Support/Endian.h" 26 #include "llvm/Support/MemoryBuffer.h" 27 #include "llvm/Support/TargetRegistry.h" 28 29 using namespace llvm; 30 using namespace llvm::object; 31 using namespace llvm::support::endian; 32 33 #define DEBUG_TYPE "dyld" 34 35 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); } 36 37 static void or32AArch64Imm(void *L, uint64_t Imm) { 38 or32le(L, (Imm & 0xFFF) << 10); 39 } 40 41 template <class T> static void write(bool isBE, void *P, T V) { 42 isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V); 43 } 44 45 static void write32AArch64Addr(void *L, uint64_t Imm) { 46 uint32_t ImmLo = (Imm & 0x3) << 29; 47 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 48 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 49 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 50 } 51 52 // Return the bits [Start, End] from Val shifted Start bits. 53 // For instance, getBits(0xF0, 4, 8) returns 0xF. 54 static uint64_t getBits(uint64_t Val, int Start, int End) { 55 uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1; 56 return (Val >> Start) & Mask; 57 } 58 59 namespace { 60 61 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> { 62 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) 63 64 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr; 65 typedef Elf_Sym_Impl<ELFT> Elf_Sym; 66 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel; 67 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela; 68 69 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; 70 71 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; 72 73 public: 74 DyldELFObject(MemoryBufferRef Wrapper, std::error_code &ec); 75 76 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 77 78 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); 79 80 // Methods for type inquiry through isa, cast and dyn_cast 81 static inline bool classof(const Binary *v) { 82 return (isa<ELFObjectFile<ELFT>>(v) && 83 classof(cast<ELFObjectFile<ELFT>>(v))); 84 } 85 static inline bool classof(const ELFObjectFile<ELFT> *v) { 86 return v->isDyldType(); 87 } 88 }; 89 90 91 92 // The MemoryBuffer passed into this constructor is just a wrapper around the 93 // actual memory. Ultimately, the Binary parent class will take ownership of 94 // this MemoryBuffer object but not the underlying memory. 95 template <class ELFT> 96 DyldELFObject<ELFT>::DyldELFObject(MemoryBufferRef Wrapper, std::error_code &EC) 97 : ELFObjectFile<ELFT>(Wrapper, EC) { 98 this->isDyldELFObject = true; 99 } 100 101 template <class ELFT> 102 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 103 uint64_t Addr) { 104 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 105 Elf_Shdr *shdr = 106 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 107 108 // This assumes the address passed in matches the target address bitness 109 // The template-based type cast handles everything else. 110 shdr->sh_addr = static_cast<addr_type>(Addr); 111 } 112 113 template <class ELFT> 114 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 115 uint64_t Addr) { 116 117 Elf_Sym *sym = const_cast<Elf_Sym *>( 118 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 119 120 // This assumes the address passed in matches the target address bitness 121 // The template-based type cast handles everything else. 122 sym->st_value = static_cast<addr_type>(Addr); 123 } 124 125 class LoadedELFObjectInfo final 126 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedELFObjectInfo> { 127 public: 128 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap) 129 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {} 130 131 OwningBinary<ObjectFile> 132 getObjectForDebug(const ObjectFile &Obj) const override; 133 }; 134 135 template <typename ELFT> 136 std::unique_ptr<DyldELFObject<ELFT>> 137 createRTDyldELFObject(MemoryBufferRef Buffer, 138 const ObjectFile &SourceObject, 139 const LoadedELFObjectInfo &L, 140 std::error_code &ec) { 141 typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr; 142 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; 143 144 std::unique_ptr<DyldELFObject<ELFT>> Obj = 145 llvm::make_unique<DyldELFObject<ELFT>>(Buffer, ec); 146 147 // Iterate over all sections in the object. 148 auto SI = SourceObject.section_begin(); 149 for (const auto &Sec : Obj->sections()) { 150 StringRef SectionName; 151 Sec.getName(SectionName); 152 if (SectionName != "") { 153 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 154 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 155 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 156 157 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { 158 // This assumes that the address passed in matches the target address 159 // bitness. The template-based type cast handles everything else. 160 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 161 } 162 } 163 ++SI; 164 } 165 166 return Obj; 167 } 168 169 OwningBinary<ObjectFile> createELFDebugObject(const ObjectFile &Obj, 170 const LoadedELFObjectInfo &L) { 171 assert(Obj.isELF() && "Not an ELF object file."); 172 173 std::unique_ptr<MemoryBuffer> Buffer = 174 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 175 176 std::error_code ec; 177 178 std::unique_ptr<ObjectFile> DebugObj; 179 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) { 180 typedef ELFType<support::little, false> ELF32LE; 181 DebugObj = createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L, 182 ec); 183 } else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) { 184 typedef ELFType<support::big, false> ELF32BE; 185 DebugObj = createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L, 186 ec); 187 } else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) { 188 typedef ELFType<support::big, true> ELF64BE; 189 DebugObj = createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L, 190 ec); 191 } else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) { 192 typedef ELFType<support::little, true> ELF64LE; 193 DebugObj = createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L, 194 ec); 195 } else 196 llvm_unreachable("Unexpected ELF format"); 197 198 assert(!ec && "Could not construct copy ELF object file"); 199 200 return OwningBinary<ObjectFile>(std::move(DebugObj), std::move(Buffer)); 201 } 202 203 OwningBinary<ObjectFile> 204 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 205 return createELFDebugObject(Obj, *this); 206 } 207 208 } // anonymous namespace 209 210 namespace llvm { 211 212 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 213 JITSymbolResolver &Resolver) 214 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 215 RuntimeDyldELF::~RuntimeDyldELF() {} 216 217 void RuntimeDyldELF::registerEHFrames() { 218 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { 219 SID EHFrameSID = UnregisteredEHFrameSections[i]; 220 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 221 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 222 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 223 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 224 RegisteredEHFrameSections.push_back(EHFrameSID); 225 } 226 UnregisteredEHFrameSections.clear(); 227 } 228 229 void RuntimeDyldELF::deregisterEHFrames() { 230 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) { 231 SID EHFrameSID = RegisteredEHFrameSections[i]; 232 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 233 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 234 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 235 MemMgr.deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 236 } 237 RegisteredEHFrameSections.clear(); 238 } 239 240 std::unique_ptr<RuntimeDyldELF> 241 llvm::RuntimeDyldELF::create(Triple::ArchType Arch, 242 RuntimeDyld::MemoryManager &MemMgr, 243 JITSymbolResolver &Resolver) { 244 switch (Arch) { 245 default: 246 return make_unique<RuntimeDyldELF>(MemMgr, Resolver); 247 case Triple::mips: 248 case Triple::mipsel: 249 case Triple::mips64: 250 case Triple::mips64el: 251 return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); 252 } 253 } 254 255 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 256 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 257 if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) 258 return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); 259 else { 260 HasError = true; 261 raw_string_ostream ErrStream(ErrorStr); 262 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, ""); 263 return nullptr; 264 } 265 } 266 267 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 268 uint64_t Offset, uint64_t Value, 269 uint32_t Type, int64_t Addend, 270 uint64_t SymOffset) { 271 switch (Type) { 272 default: 273 llvm_unreachable("Relocation type not implemented yet!"); 274 break; 275 case ELF::R_X86_64_NONE: 276 break; 277 case ELF::R_X86_64_64: { 278 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 279 Value + Addend; 280 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 281 << format("%p\n", Section.getAddressWithOffset(Offset))); 282 break; 283 } 284 case ELF::R_X86_64_32: 285 case ELF::R_X86_64_32S: { 286 Value += Addend; 287 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 288 (Type == ELF::R_X86_64_32S && 289 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 290 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 291 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 292 TruncatedAddr; 293 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 294 << format("%p\n", Section.getAddressWithOffset(Offset))); 295 break; 296 } 297 case ELF::R_X86_64_PC8: { 298 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 299 int64_t RealOffset = Value + Addend - FinalAddress; 300 assert(isInt<8>(RealOffset)); 301 int8_t TruncOffset = (RealOffset & 0xFF); 302 Section.getAddress()[Offset] = TruncOffset; 303 break; 304 } 305 case ELF::R_X86_64_PC32: { 306 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 307 int64_t RealOffset = Value + Addend - FinalAddress; 308 assert(isInt<32>(RealOffset)); 309 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 310 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 311 TruncOffset; 312 break; 313 } 314 case ELF::R_X86_64_PC64: { 315 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 316 int64_t RealOffset = Value + Addend - FinalAddress; 317 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 318 RealOffset; 319 break; 320 } 321 } 322 } 323 324 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 325 uint64_t Offset, uint32_t Value, 326 uint32_t Type, int32_t Addend) { 327 switch (Type) { 328 case ELF::R_386_32: { 329 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 330 Value + Addend; 331 break; 332 } 333 case ELF::R_386_PC32: { 334 uint32_t FinalAddress = 335 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 336 uint32_t RealOffset = Value + Addend - FinalAddress; 337 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 338 RealOffset; 339 break; 340 } 341 default: 342 // There are other relocation types, but it appears these are the 343 // only ones currently used by the LLVM ELF object writer 344 llvm_unreachable("Relocation type not implemented yet!"); 345 break; 346 } 347 } 348 349 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 350 uint64_t Offset, uint64_t Value, 351 uint32_t Type, int64_t Addend) { 352 uint32_t *TargetPtr = 353 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 354 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 355 // Data should use target endian. Code should always use little endian. 356 bool isBE = Arch == Triple::aarch64_be; 357 358 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 359 << format("%llx", Section.getAddressWithOffset(Offset)) 360 << " FinalAddress: 0x" << format("%llx", FinalAddress) 361 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 362 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend) 363 << "\n"); 364 365 switch (Type) { 366 default: 367 llvm_unreachable("Relocation type not implemented yet!"); 368 break; 369 case ELF::R_AARCH64_ABS64: 370 write(isBE, TargetPtr, Value + Addend); 371 break; 372 case ELF::R_AARCH64_PREL32: { 373 uint64_t Result = Value + Addend - FinalAddress; 374 assert(static_cast<int64_t>(Result) >= INT32_MIN && 375 static_cast<int64_t>(Result) <= UINT32_MAX); 376 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 377 break; 378 } 379 case ELF::R_AARCH64_PREL64: 380 write(isBE, TargetPtr, Value + Addend - FinalAddress); 381 break; 382 case ELF::R_AARCH64_CALL26: // fallthrough 383 case ELF::R_AARCH64_JUMP26: { 384 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 385 // calculation. 386 uint64_t BranchImm = Value + Addend - FinalAddress; 387 388 // "Check that -2^27 <= result < 2^27". 389 assert(isInt<28>(BranchImm)); 390 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 391 break; 392 } 393 case ELF::R_AARCH64_MOVW_UABS_G3: 394 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 395 break; 396 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 397 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 398 break; 399 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 400 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 401 break; 402 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 403 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 404 break; 405 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 406 // Operation: Page(S+A) - Page(P) 407 uint64_t Result = 408 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 409 410 // Check that -2^32 <= X < 2^32 411 assert(isInt<33>(Result) && "overflow check failed for relocation"); 412 413 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 414 // from bits 32:12 of X. 415 write32AArch64Addr(TargetPtr, Result >> 12); 416 break; 417 } 418 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 419 // Operation: S + A 420 // Immediate goes in bits 21:10 of LD/ST instruction, taken 421 // from bits 11:0 of X 422 or32AArch64Imm(TargetPtr, Value + Addend); 423 break; 424 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 425 // Operation: S + A 426 // Immediate goes in bits 21:10 of LD/ST instruction, taken 427 // from bits 11:0 of X 428 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 429 break; 430 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 431 // Operation: S + A 432 // Immediate goes in bits 21:10 of LD/ST instruction, taken 433 // from bits 11:1 of X 434 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 435 break; 436 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 437 // Operation: S + A 438 // Immediate goes in bits 21:10 of LD/ST instruction, taken 439 // from bits 11:2 of X 440 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 441 break; 442 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 443 // Operation: S + A 444 // Immediate goes in bits 21:10 of LD/ST instruction, taken 445 // from bits 11:3 of X 446 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 447 break; 448 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 449 // Operation: S + A 450 // Immediate goes in bits 21:10 of LD/ST instruction, taken 451 // from bits 11:4 of X 452 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 453 break; 454 } 455 } 456 457 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 458 uint64_t Offset, uint32_t Value, 459 uint32_t Type, int32_t Addend) { 460 // TODO: Add Thumb relocations. 461 uint32_t *TargetPtr = 462 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 463 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 464 Value += Addend; 465 466 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 467 << Section.getAddressWithOffset(Offset) 468 << " FinalAddress: " << format("%p", FinalAddress) << " Value: " 469 << format("%x", Value) << " Type: " << format("%x", Type) 470 << " Addend: " << format("%x", Addend) << "\n"); 471 472 switch (Type) { 473 default: 474 llvm_unreachable("Not implemented relocation type!"); 475 476 case ELF::R_ARM_NONE: 477 break; 478 // Write a 31bit signed offset 479 case ELF::R_ARM_PREL31: 480 support::ulittle32_t::ref{TargetPtr} = 481 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 482 ((Value - FinalAddress) & ~0x80000000); 483 break; 484 case ELF::R_ARM_TARGET1: 485 case ELF::R_ARM_ABS32: 486 support::ulittle32_t::ref{TargetPtr} = Value; 487 break; 488 // Write first 16 bit of 32 bit value to the mov instruction. 489 // Last 4 bit should be shifted. 490 case ELF::R_ARM_MOVW_ABS_NC: 491 case ELF::R_ARM_MOVT_ABS: 492 if (Type == ELF::R_ARM_MOVW_ABS_NC) 493 Value = Value & 0xFFFF; 494 else if (Type == ELF::R_ARM_MOVT_ABS) 495 Value = (Value >> 16) & 0xFFFF; 496 support::ulittle32_t::ref{TargetPtr} = 497 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 498 (((Value >> 12) & 0xF) << 16); 499 break; 500 // Write 24 bit relative value to the branch instruction. 501 case ELF::R_ARM_PC24: // Fall through. 502 case ELF::R_ARM_CALL: // Fall through. 503 case ELF::R_ARM_JUMP24: 504 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 505 RelValue = (RelValue & 0x03FFFFFC) >> 2; 506 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 507 support::ulittle32_t::ref{TargetPtr} = 508 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 509 break; 510 } 511 } 512 513 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 514 if (Arch == Triple::UnknownArch || 515 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 516 IsMipsO32ABI = false; 517 IsMipsN32ABI = false; 518 IsMipsN64ABI = false; 519 return; 520 } 521 unsigned AbiVariant; 522 Obj.getPlatformFlags(AbiVariant); 523 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 524 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 525 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); 526 } 527 528 // Return the .TOC. section and offset. 529 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 530 ObjSectionToIDMap &LocalSections, 531 RelocationValueRef &Rel) { 532 // Set a default SectionID in case we do not find a TOC section below. 533 // This may happen for references to TOC base base (sym@toc, .odp 534 // relocation) without a .toc directive. In this case just use the 535 // first section (which is usually the .odp) since the code won't 536 // reference the .toc base directly. 537 Rel.SymbolName = nullptr; 538 Rel.SectionID = 0; 539 540 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 541 // order. The TOC starts where the first of these sections starts. 542 for (auto &Section: Obj.sections()) { 543 StringRef SectionName; 544 if (auto EC = Section.getName(SectionName)) 545 return errorCodeToError(EC); 546 547 if (SectionName == ".got" 548 || SectionName == ".toc" 549 || SectionName == ".tocbss" 550 || SectionName == ".plt") { 551 if (auto SectionIDOrErr = 552 findOrEmitSection(Obj, Section, false, LocalSections)) 553 Rel.SectionID = *SectionIDOrErr; 554 else 555 return SectionIDOrErr.takeError(); 556 break; 557 } 558 } 559 560 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 561 // thus permitting a full 64 Kbytes segment. 562 Rel.Addend = 0x8000; 563 564 return Error::success(); 565 } 566 567 // Returns the sections and offset associated with the ODP entry referenced 568 // by Symbol. 569 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 570 ObjSectionToIDMap &LocalSections, 571 RelocationValueRef &Rel) { 572 // Get the ELF symbol value (st_value) to compare with Relocation offset in 573 // .opd entries 574 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 575 si != se; ++si) { 576 section_iterator RelSecI = si->getRelocatedSection(); 577 if (RelSecI == Obj.section_end()) 578 continue; 579 580 StringRef RelSectionName; 581 if (auto EC = RelSecI->getName(RelSectionName)) 582 return errorCodeToError(EC); 583 584 if (RelSectionName != ".opd") 585 continue; 586 587 for (elf_relocation_iterator i = si->relocation_begin(), 588 e = si->relocation_end(); 589 i != e;) { 590 // The R_PPC64_ADDR64 relocation indicates the first field 591 // of a .opd entry 592 uint64_t TypeFunc = i->getType(); 593 if (TypeFunc != ELF::R_PPC64_ADDR64) { 594 ++i; 595 continue; 596 } 597 598 uint64_t TargetSymbolOffset = i->getOffset(); 599 symbol_iterator TargetSymbol = i->getSymbol(); 600 int64_t Addend; 601 if (auto AddendOrErr = i->getAddend()) 602 Addend = *AddendOrErr; 603 else 604 return errorCodeToError(AddendOrErr.getError()); 605 606 ++i; 607 if (i == e) 608 break; 609 610 // Just check if following relocation is a R_PPC64_TOC 611 uint64_t TypeTOC = i->getType(); 612 if (TypeTOC != ELF::R_PPC64_TOC) 613 continue; 614 615 // Finally compares the Symbol value and the target symbol offset 616 // to check if this .opd entry refers to the symbol the relocation 617 // points to. 618 if (Rel.Addend != (int64_t)TargetSymbolOffset) 619 continue; 620 621 section_iterator TSI = Obj.section_end(); 622 if (auto TSIOrErr = TargetSymbol->getSection()) 623 TSI = *TSIOrErr; 624 else 625 return TSIOrErr.takeError(); 626 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 627 628 bool IsCode = TSI->isText(); 629 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 630 LocalSections)) 631 Rel.SectionID = *SectionIDOrErr; 632 else 633 return SectionIDOrErr.takeError(); 634 Rel.Addend = (intptr_t)Addend; 635 return Error::success(); 636 } 637 } 638 llvm_unreachable("Attempting to get address of ODP entry!"); 639 } 640 641 // Relocation masks following the #lo(value), #hi(value), #ha(value), 642 // #higher(value), #highera(value), #highest(value), and #highesta(value) 643 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 644 // document. 645 646 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 647 648 static inline uint16_t applyPPChi(uint64_t value) { 649 return (value >> 16) & 0xffff; 650 } 651 652 static inline uint16_t applyPPCha (uint64_t value) { 653 return ((value + 0x8000) >> 16) & 0xffff; 654 } 655 656 static inline uint16_t applyPPChigher(uint64_t value) { 657 return (value >> 32) & 0xffff; 658 } 659 660 static inline uint16_t applyPPChighera (uint64_t value) { 661 return ((value + 0x8000) >> 32) & 0xffff; 662 } 663 664 static inline uint16_t applyPPChighest(uint64_t value) { 665 return (value >> 48) & 0xffff; 666 } 667 668 static inline uint16_t applyPPChighesta (uint64_t value) { 669 return ((value + 0x8000) >> 48) & 0xffff; 670 } 671 672 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 673 uint64_t Offset, uint64_t Value, 674 uint32_t Type, int64_t Addend) { 675 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 676 switch (Type) { 677 default: 678 llvm_unreachable("Relocation type not implemented yet!"); 679 break; 680 case ELF::R_PPC_ADDR16_LO: 681 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 682 break; 683 case ELF::R_PPC_ADDR16_HI: 684 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 685 break; 686 case ELF::R_PPC_ADDR16_HA: 687 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 688 break; 689 } 690 } 691 692 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 693 uint64_t Offset, uint64_t Value, 694 uint32_t Type, int64_t Addend) { 695 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 696 switch (Type) { 697 default: 698 llvm_unreachable("Relocation type not implemented yet!"); 699 break; 700 case ELF::R_PPC64_ADDR16: 701 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 702 break; 703 case ELF::R_PPC64_ADDR16_DS: 704 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 705 break; 706 case ELF::R_PPC64_ADDR16_LO: 707 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 708 break; 709 case ELF::R_PPC64_ADDR16_LO_DS: 710 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 711 break; 712 case ELF::R_PPC64_ADDR16_HI: 713 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 714 break; 715 case ELF::R_PPC64_ADDR16_HA: 716 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 717 break; 718 case ELF::R_PPC64_ADDR16_HIGHER: 719 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 720 break; 721 case ELF::R_PPC64_ADDR16_HIGHERA: 722 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 723 break; 724 case ELF::R_PPC64_ADDR16_HIGHEST: 725 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 726 break; 727 case ELF::R_PPC64_ADDR16_HIGHESTA: 728 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 729 break; 730 case ELF::R_PPC64_ADDR14: { 731 assert(((Value + Addend) & 3) == 0); 732 // Preserve the AA/LK bits in the branch instruction 733 uint8_t aalk = *(LocalAddress + 3); 734 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 735 } break; 736 case ELF::R_PPC64_REL16_LO: { 737 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 738 uint64_t Delta = Value - FinalAddress + Addend; 739 writeInt16BE(LocalAddress, applyPPClo(Delta)); 740 } break; 741 case ELF::R_PPC64_REL16_HI: { 742 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 743 uint64_t Delta = Value - FinalAddress + Addend; 744 writeInt16BE(LocalAddress, applyPPChi(Delta)); 745 } break; 746 case ELF::R_PPC64_REL16_HA: { 747 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 748 uint64_t Delta = Value - FinalAddress + Addend; 749 writeInt16BE(LocalAddress, applyPPCha(Delta)); 750 } break; 751 case ELF::R_PPC64_ADDR32: { 752 int32_t Result = static_cast<int32_t>(Value + Addend); 753 if (SignExtend32<32>(Result) != Result) 754 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 755 writeInt32BE(LocalAddress, Result); 756 } break; 757 case ELF::R_PPC64_REL24: { 758 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 759 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 760 if (SignExtend32<26>(delta) != delta) 761 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 762 // Generates a 'bl <address>' instruction 763 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); 764 } break; 765 case ELF::R_PPC64_REL32: { 766 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 767 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 768 if (SignExtend32<32>(delta) != delta) 769 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 770 writeInt32BE(LocalAddress, delta); 771 } break; 772 case ELF::R_PPC64_REL64: { 773 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 774 uint64_t Delta = Value - FinalAddress + Addend; 775 writeInt64BE(LocalAddress, Delta); 776 } break; 777 case ELF::R_PPC64_ADDR64: 778 writeInt64BE(LocalAddress, Value + Addend); 779 break; 780 } 781 } 782 783 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 784 uint64_t Offset, uint64_t Value, 785 uint32_t Type, int64_t Addend) { 786 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 787 switch (Type) { 788 default: 789 llvm_unreachable("Relocation type not implemented yet!"); 790 break; 791 case ELF::R_390_PC16DBL: 792 case ELF::R_390_PLT16DBL: { 793 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 794 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 795 writeInt16BE(LocalAddress, Delta / 2); 796 break; 797 } 798 case ELF::R_390_PC32DBL: 799 case ELF::R_390_PLT32DBL: { 800 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 801 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 802 writeInt32BE(LocalAddress, Delta / 2); 803 break; 804 } 805 case ELF::R_390_PC32: { 806 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 807 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 808 writeInt32BE(LocalAddress, Delta); 809 break; 810 } 811 case ELF::R_390_64: 812 writeInt64BE(LocalAddress, Value + Addend); 813 break; 814 case ELF::R_390_PC64: { 815 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 816 writeInt64BE(LocalAddress, Delta); 817 break; 818 } 819 } 820 } 821 822 // The target location for the relocation is described by RE.SectionID and 823 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 824 // SectionEntry has three members describing its location. 825 // SectionEntry::Address is the address at which the section has been loaded 826 // into memory in the current (host) process. SectionEntry::LoadAddress is the 827 // address that the section will have in the target process. 828 // SectionEntry::ObjAddress is the address of the bits for this section in the 829 // original emitted object image (also in the current address space). 830 // 831 // Relocations will be applied as if the section were loaded at 832 // SectionEntry::LoadAddress, but they will be applied at an address based 833 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 834 // Target memory contents if they are required for value calculations. 835 // 836 // The Value parameter here is the load address of the symbol for the 837 // relocation to be applied. For relocations which refer to symbols in the 838 // current object Value will be the LoadAddress of the section in which 839 // the symbol resides (RE.Addend provides additional information about the 840 // symbol location). For external symbols, Value will be the address of the 841 // symbol in the target address space. 842 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 843 uint64_t Value) { 844 const SectionEntry &Section = Sections[RE.SectionID]; 845 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 846 RE.SymOffset, RE.SectionID); 847 } 848 849 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 850 uint64_t Offset, uint64_t Value, 851 uint32_t Type, int64_t Addend, 852 uint64_t SymOffset, SID SectionID) { 853 switch (Arch) { 854 case Triple::x86_64: 855 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 856 break; 857 case Triple::x86: 858 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 859 (uint32_t)(Addend & 0xffffffffL)); 860 break; 861 case Triple::aarch64: 862 case Triple::aarch64_be: 863 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 864 break; 865 case Triple::arm: // Fall through. 866 case Triple::armeb: 867 case Triple::thumb: 868 case Triple::thumbeb: 869 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 870 (uint32_t)(Addend & 0xffffffffL)); 871 break; 872 case Triple::ppc: 873 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 874 break; 875 case Triple::ppc64: // Fall through. 876 case Triple::ppc64le: 877 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 878 break; 879 case Triple::systemz: 880 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 881 break; 882 default: 883 llvm_unreachable("Unsupported CPU type!"); 884 } 885 } 886 887 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 888 return (void *)(Sections[SectionID].getObjAddress() + Offset); 889 } 890 891 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 892 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 893 if (Value.SymbolName) 894 addRelocationForSymbol(RE, Value.SymbolName); 895 else 896 addRelocationForSection(RE, Value.SectionID); 897 } 898 899 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 900 bool IsLocal) const { 901 switch (RelType) { 902 case ELF::R_MICROMIPS_GOT16: 903 if (IsLocal) 904 return ELF::R_MICROMIPS_LO16; 905 break; 906 case ELF::R_MICROMIPS_HI16: 907 return ELF::R_MICROMIPS_LO16; 908 case ELF::R_MIPS_GOT16: 909 if (IsLocal) 910 return ELF::R_MIPS_LO16; 911 break; 912 case ELF::R_MIPS_HI16: 913 return ELF::R_MIPS_LO16; 914 case ELF::R_MIPS_PCHI16: 915 return ELF::R_MIPS_PCLO16; 916 default: 917 break; 918 } 919 return ELF::R_MIPS_NONE; 920 } 921 922 // Sometimes we don't need to create thunk for a branch. 923 // This typically happens when branch target is located 924 // in the same object file. In such case target is either 925 // a weak symbol or symbol in a different executable section. 926 // This function checks if branch target is located in the 927 // same object file and if distance between source and target 928 // fits R_AARCH64_CALL26 relocation. If both conditions are 929 // met, it emits direct jump to the target and returns true. 930 // Otherwise false is returned and thunk is created. 931 bool RuntimeDyldELF::resolveAArch64ShortBranch( 932 unsigned SectionID, relocation_iterator RelI, 933 const RelocationValueRef &Value) { 934 uint64_t Address; 935 if (Value.SymbolName) { 936 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 937 938 // Don't create direct branch for external symbols. 939 if (Loc == GlobalSymbolTable.end()) 940 return false; 941 942 const auto &SymInfo = Loc->second; 943 Address = 944 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 945 SymInfo.getOffset())); 946 } else { 947 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 948 } 949 uint64_t Offset = RelI->getOffset(); 950 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 951 952 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 953 // If distance between source and target is out of range then we should 954 // create thunk. 955 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 956 return false; 957 958 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 959 Value.Addend); 960 961 return true; 962 } 963 964 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 965 const RelocationValueRef &Value, 966 relocation_iterator RelI, 967 StubMap &Stubs) { 968 969 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 970 SectionEntry &Section = Sections[SectionID]; 971 972 uint64_t Offset = RelI->getOffset(); 973 unsigned RelType = RelI->getType(); 974 // Look for an existing stub. 975 StubMap::const_iterator i = Stubs.find(Value); 976 if (i != Stubs.end()) { 977 resolveRelocation(Section, Offset, 978 (uint64_t)Section.getAddressWithOffset(i->second), 979 RelType, 0); 980 DEBUG(dbgs() << " Stub function found\n"); 981 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 982 // Create a new stub function. 983 DEBUG(dbgs() << " Create a new stub function\n"); 984 Stubs[Value] = Section.getStubOffset(); 985 uint8_t *StubTargetAddr = createStubFunction( 986 Section.getAddressWithOffset(Section.getStubOffset())); 987 988 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 989 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 990 RelocationEntry REmovk_g2(SectionID, 991 StubTargetAddr - Section.getAddress() + 4, 992 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 993 RelocationEntry REmovk_g1(SectionID, 994 StubTargetAddr - Section.getAddress() + 8, 995 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 996 RelocationEntry REmovk_g0(SectionID, 997 StubTargetAddr - Section.getAddress() + 12, 998 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 999 1000 if (Value.SymbolName) { 1001 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1002 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1003 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1004 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1005 } else { 1006 addRelocationForSection(REmovz_g3, Value.SectionID); 1007 addRelocationForSection(REmovk_g2, Value.SectionID); 1008 addRelocationForSection(REmovk_g1, Value.SectionID); 1009 addRelocationForSection(REmovk_g0, Value.SectionID); 1010 } 1011 resolveRelocation(Section, Offset, 1012 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1013 Section.getStubOffset())), 1014 RelType, 0); 1015 Section.advanceStubOffset(getMaxStubSize()); 1016 } 1017 } 1018 1019 Expected<relocation_iterator> 1020 RuntimeDyldELF::processRelocationRef( 1021 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1022 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1023 const auto &Obj = cast<ELFObjectFileBase>(O); 1024 uint64_t RelType = RelI->getType(); 1025 ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend(); 1026 int64_t Addend = AddendOrErr ? *AddendOrErr : 0; 1027 elf_symbol_iterator Symbol = RelI->getSymbol(); 1028 1029 // Obtain the symbol name which is referenced in the relocation 1030 StringRef TargetName; 1031 if (Symbol != Obj.symbol_end()) { 1032 if (auto TargetNameOrErr = Symbol->getName()) 1033 TargetName = *TargetNameOrErr; 1034 else 1035 return TargetNameOrErr.takeError(); 1036 } 1037 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1038 << " TargetName: " << TargetName << "\n"); 1039 RelocationValueRef Value; 1040 // First search for the symbol in the local symbol table 1041 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1042 1043 // Search for the symbol in the global symbol table 1044 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1045 if (Symbol != Obj.symbol_end()) { 1046 gsi = GlobalSymbolTable.find(TargetName.data()); 1047 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1048 if (!SymTypeOrErr) { 1049 std::string Buf; 1050 raw_string_ostream OS(Buf); 1051 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, ""); 1052 OS.flush(); 1053 report_fatal_error(Buf); 1054 } 1055 SymType = *SymTypeOrErr; 1056 } 1057 if (gsi != GlobalSymbolTable.end()) { 1058 const auto &SymInfo = gsi->second; 1059 Value.SectionID = SymInfo.getSectionID(); 1060 Value.Offset = SymInfo.getOffset(); 1061 Value.Addend = SymInfo.getOffset() + Addend; 1062 } else { 1063 switch (SymType) { 1064 case SymbolRef::ST_Debug: { 1065 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1066 // and can be changed by another developers. Maybe best way is add 1067 // a new symbol type ST_Section to SymbolRef and use it. 1068 auto SectionOrErr = Symbol->getSection(); 1069 if (!SectionOrErr) { 1070 std::string Buf; 1071 raw_string_ostream OS(Buf); 1072 logAllUnhandledErrors(SectionOrErr.takeError(), OS, ""); 1073 OS.flush(); 1074 report_fatal_error(Buf); 1075 } 1076 section_iterator si = *SectionOrErr; 1077 if (si == Obj.section_end()) 1078 llvm_unreachable("Symbol section not found, bad object file format!"); 1079 DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1080 bool isCode = si->isText(); 1081 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1082 ObjSectionToID)) 1083 Value.SectionID = *SectionIDOrErr; 1084 else 1085 return SectionIDOrErr.takeError(); 1086 Value.Addend = Addend; 1087 break; 1088 } 1089 case SymbolRef::ST_Data: 1090 case SymbolRef::ST_Function: 1091 case SymbolRef::ST_Unknown: { 1092 Value.SymbolName = TargetName.data(); 1093 Value.Addend = Addend; 1094 1095 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1096 // will manifest here as a NULL symbol name. 1097 // We can set this as a valid (but empty) symbol name, and rely 1098 // on addRelocationForSymbol to handle this. 1099 if (!Value.SymbolName) 1100 Value.SymbolName = ""; 1101 break; 1102 } 1103 default: 1104 llvm_unreachable("Unresolved symbol type!"); 1105 break; 1106 } 1107 } 1108 1109 uint64_t Offset = RelI->getOffset(); 1110 1111 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1112 << "\n"); 1113 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1114 if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { 1115 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1116 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1117 // Craete new GOT entry or find existing one. If GOT entry is 1118 // to be created, then we also emit ABS64 relocation for it. 1119 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1120 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1121 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1122 1123 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1124 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1125 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1126 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1127 } else { 1128 processSimpleRelocation(SectionID, Offset, RelType, Value); 1129 } 1130 } else if (Arch == Triple::arm) { 1131 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1132 RelType == ELF::R_ARM_JUMP24) { 1133 // This is an ARM branch relocation, need to use a stub function. 1134 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1135 SectionEntry &Section = Sections[SectionID]; 1136 1137 // Look for an existing stub. 1138 StubMap::const_iterator i = Stubs.find(Value); 1139 if (i != Stubs.end()) { 1140 resolveRelocation( 1141 Section, Offset, 1142 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1143 RelType, 0); 1144 DEBUG(dbgs() << " Stub function found\n"); 1145 } else { 1146 // Create a new stub function. 1147 DEBUG(dbgs() << " Create a new stub function\n"); 1148 Stubs[Value] = Section.getStubOffset(); 1149 uint8_t *StubTargetAddr = createStubFunction( 1150 Section.getAddressWithOffset(Section.getStubOffset())); 1151 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1152 ELF::R_ARM_ABS32, Value.Addend); 1153 if (Value.SymbolName) 1154 addRelocationForSymbol(RE, Value.SymbolName); 1155 else 1156 addRelocationForSection(RE, Value.SectionID); 1157 1158 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1159 Section.getAddressWithOffset( 1160 Section.getStubOffset())), 1161 RelType, 0); 1162 Section.advanceStubOffset(getMaxStubSize()); 1163 } 1164 } else { 1165 uint32_t *Placeholder = 1166 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1167 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1168 RelType == ELF::R_ARM_ABS32) { 1169 Value.Addend += *Placeholder; 1170 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1171 // See ELF for ARM documentation 1172 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1173 } 1174 processSimpleRelocation(SectionID, Offset, RelType, Value); 1175 } 1176 } else if (IsMipsO32ABI) { 1177 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1178 computePlaceholderAddress(SectionID, Offset)); 1179 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1180 if (RelType == ELF::R_MIPS_26) { 1181 // This is an Mips branch relocation, need to use a stub function. 1182 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1183 SectionEntry &Section = Sections[SectionID]; 1184 1185 // Extract the addend from the instruction. 1186 // We shift up by two since the Value will be down shifted again 1187 // when applying the relocation. 1188 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1189 1190 Value.Addend += Addend; 1191 1192 // Look up for existing stub. 1193 StubMap::const_iterator i = Stubs.find(Value); 1194 if (i != Stubs.end()) { 1195 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1196 addRelocationForSection(RE, SectionID); 1197 DEBUG(dbgs() << " Stub function found\n"); 1198 } else { 1199 // Create a new stub function. 1200 DEBUG(dbgs() << " Create a new stub function\n"); 1201 Stubs[Value] = Section.getStubOffset(); 1202 1203 unsigned AbiVariant; 1204 O.getPlatformFlags(AbiVariant); 1205 1206 uint8_t *StubTargetAddr = createStubFunction( 1207 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1208 1209 // Creating Hi and Lo relocations for the filled stub instructions. 1210 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1211 ELF::R_MIPS_HI16, Value.Addend); 1212 RelocationEntry RELo(SectionID, 1213 StubTargetAddr - Section.getAddress() + 4, 1214 ELF::R_MIPS_LO16, Value.Addend); 1215 1216 if (Value.SymbolName) { 1217 addRelocationForSymbol(REHi, Value.SymbolName); 1218 addRelocationForSymbol(RELo, Value.SymbolName); 1219 } 1220 else { 1221 addRelocationForSection(REHi, Value.SectionID); 1222 addRelocationForSection(RELo, Value.SectionID); 1223 } 1224 1225 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1226 addRelocationForSection(RE, SectionID); 1227 Section.advanceStubOffset(getMaxStubSize()); 1228 } 1229 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1230 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1231 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1232 PendingRelocs.push_back(std::make_pair(Value, RE)); 1233 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1234 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1235 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1236 const RelocationValueRef &MatchingValue = I->first; 1237 RelocationEntry &Reloc = I->second; 1238 if (MatchingValue == Value && 1239 RelType == getMatchingLoRelocation(Reloc.RelType) && 1240 SectionID == Reloc.SectionID) { 1241 Reloc.Addend += Addend; 1242 if (Value.SymbolName) 1243 addRelocationForSymbol(Reloc, Value.SymbolName); 1244 else 1245 addRelocationForSection(Reloc, Value.SectionID); 1246 I = PendingRelocs.erase(I); 1247 } else 1248 ++I; 1249 } 1250 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1251 if (Value.SymbolName) 1252 addRelocationForSymbol(RE, Value.SymbolName); 1253 else 1254 addRelocationForSection(RE, Value.SectionID); 1255 } else { 1256 if (RelType == ELF::R_MIPS_32) 1257 Value.Addend += Opcode; 1258 else if (RelType == ELF::R_MIPS_PC16) 1259 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1260 else if (RelType == ELF::R_MIPS_PC19_S2) 1261 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1262 else if (RelType == ELF::R_MIPS_PC21_S2) 1263 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1264 else if (RelType == ELF::R_MIPS_PC26_S2) 1265 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1266 processSimpleRelocation(SectionID, Offset, RelType, Value); 1267 } 1268 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1269 uint32_t r_type = RelType & 0xff; 1270 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1271 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1272 || r_type == ELF::R_MIPS_GOT_DISP) { 1273 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1274 if (i != GOTSymbolOffsets.end()) 1275 RE.SymOffset = i->second; 1276 else { 1277 RE.SymOffset = allocateGOTEntries(1); 1278 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1279 } 1280 } 1281 if (Value.SymbolName) 1282 addRelocationForSymbol(RE, Value.SymbolName); 1283 else 1284 addRelocationForSection(RE, Value.SectionID); 1285 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1286 if (RelType == ELF::R_PPC64_REL24) { 1287 // Determine ABI variant in use for this object. 1288 unsigned AbiVariant; 1289 Obj.getPlatformFlags(AbiVariant); 1290 AbiVariant &= ELF::EF_PPC64_ABI; 1291 // A PPC branch relocation will need a stub function if the target is 1292 // an external symbol (Symbol::ST_Unknown) or if the target address 1293 // is not within the signed 24-bits branch address. 1294 SectionEntry &Section = Sections[SectionID]; 1295 uint8_t *Target = Section.getAddressWithOffset(Offset); 1296 bool RangeOverflow = false; 1297 if (SymType != SymbolRef::ST_Unknown) { 1298 if (AbiVariant != 2) { 1299 // In the ELFv1 ABI, a function call may point to the .opd entry, 1300 // so the final symbol value is calculated based on the relocation 1301 // values in the .opd section. 1302 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1303 return std::move(Err); 1304 } else { 1305 // In the ELFv2 ABI, a function symbol may provide a local entry 1306 // point, which must be used for direct calls. 1307 uint8_t SymOther = Symbol->getOther(); 1308 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1309 } 1310 uint8_t *RelocTarget = 1311 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1312 int32_t delta = static_cast<int32_t>(Target - RelocTarget); 1313 // If it is within 26-bits branch range, just set the branch target 1314 if (SignExtend32<26>(delta) == delta) { 1315 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1316 if (Value.SymbolName) 1317 addRelocationForSymbol(RE, Value.SymbolName); 1318 else 1319 addRelocationForSection(RE, Value.SectionID); 1320 } else { 1321 RangeOverflow = true; 1322 } 1323 } 1324 if (SymType == SymbolRef::ST_Unknown || RangeOverflow) { 1325 // It is an external symbol (SymbolRef::ST_Unknown) or within a range 1326 // larger than 24-bits. 1327 StubMap::const_iterator i = Stubs.find(Value); 1328 if (i != Stubs.end()) { 1329 // Symbol function stub already created, just relocate to it 1330 resolveRelocation(Section, Offset, 1331 reinterpret_cast<uint64_t>( 1332 Section.getAddressWithOffset(i->second)), 1333 RelType, 0); 1334 DEBUG(dbgs() << " Stub function found\n"); 1335 } else { 1336 // Create a new stub function. 1337 DEBUG(dbgs() << " Create a new stub function\n"); 1338 Stubs[Value] = Section.getStubOffset(); 1339 uint8_t *StubTargetAddr = createStubFunction( 1340 Section.getAddressWithOffset(Section.getStubOffset()), 1341 AbiVariant); 1342 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1343 ELF::R_PPC64_ADDR64, Value.Addend); 1344 1345 // Generates the 64-bits address loads as exemplified in section 1346 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1347 // apply to the low part of the instructions, so we have to update 1348 // the offset according to the target endianness. 1349 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1350 if (!IsTargetLittleEndian) 1351 StubRelocOffset += 2; 1352 1353 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1354 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1355 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1356 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1357 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1358 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1359 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1360 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1361 1362 if (Value.SymbolName) { 1363 addRelocationForSymbol(REhst, Value.SymbolName); 1364 addRelocationForSymbol(REhr, Value.SymbolName); 1365 addRelocationForSymbol(REh, Value.SymbolName); 1366 addRelocationForSymbol(REl, Value.SymbolName); 1367 } else { 1368 addRelocationForSection(REhst, Value.SectionID); 1369 addRelocationForSection(REhr, Value.SectionID); 1370 addRelocationForSection(REh, Value.SectionID); 1371 addRelocationForSection(REl, Value.SectionID); 1372 } 1373 1374 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1375 Section.getAddressWithOffset( 1376 Section.getStubOffset())), 1377 RelType, 0); 1378 Section.advanceStubOffset(getMaxStubSize()); 1379 } 1380 if (SymType == SymbolRef::ST_Unknown) { 1381 // Restore the TOC for external calls 1382 if (AbiVariant == 2) 1383 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1) 1384 else 1385 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1386 } 1387 } 1388 } else if (RelType == ELF::R_PPC64_TOC16 || 1389 RelType == ELF::R_PPC64_TOC16_DS || 1390 RelType == ELF::R_PPC64_TOC16_LO || 1391 RelType == ELF::R_PPC64_TOC16_LO_DS || 1392 RelType == ELF::R_PPC64_TOC16_HI || 1393 RelType == ELF::R_PPC64_TOC16_HA) { 1394 // These relocations are supposed to subtract the TOC address from 1395 // the final value. This does not fit cleanly into the RuntimeDyld 1396 // scheme, since there may be *two* sections involved in determining 1397 // the relocation value (the section of the symbol referred to by the 1398 // relocation, and the TOC section associated with the current module). 1399 // 1400 // Fortunately, these relocations are currently only ever generated 1401 // referring to symbols that themselves reside in the TOC, which means 1402 // that the two sections are actually the same. Thus they cancel out 1403 // and we can immediately resolve the relocation right now. 1404 switch (RelType) { 1405 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1406 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1407 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1408 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1409 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1410 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1411 default: llvm_unreachable("Wrong relocation type."); 1412 } 1413 1414 RelocationValueRef TOCValue; 1415 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1416 return std::move(Err); 1417 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1418 llvm_unreachable("Unsupported TOC relocation."); 1419 Value.Addend -= TOCValue.Addend; 1420 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1421 } else { 1422 // There are two ways to refer to the TOC address directly: either 1423 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1424 // ignored), or via any relocation that refers to the magic ".TOC." 1425 // symbols (in which case the addend is respected). 1426 if (RelType == ELF::R_PPC64_TOC) { 1427 RelType = ELF::R_PPC64_ADDR64; 1428 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1429 return std::move(Err); 1430 } else if (TargetName == ".TOC.") { 1431 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1432 return std::move(Err); 1433 Value.Addend += Addend; 1434 } 1435 1436 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1437 1438 if (Value.SymbolName) 1439 addRelocationForSymbol(RE, Value.SymbolName); 1440 else 1441 addRelocationForSection(RE, Value.SectionID); 1442 } 1443 } else if (Arch == Triple::systemz && 1444 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1445 // Create function stubs for both PLT and GOT references, regardless of 1446 // whether the GOT reference is to data or code. The stub contains the 1447 // full address of the symbol, as needed by GOT references, and the 1448 // executable part only adds an overhead of 8 bytes. 1449 // 1450 // We could try to conserve space by allocating the code and data 1451 // parts of the stub separately. However, as things stand, we allocate 1452 // a stub for every relocation, so using a GOT in JIT code should be 1453 // no less space efficient than using an explicit constant pool. 1454 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1455 SectionEntry &Section = Sections[SectionID]; 1456 1457 // Look for an existing stub. 1458 StubMap::const_iterator i = Stubs.find(Value); 1459 uintptr_t StubAddress; 1460 if (i != Stubs.end()) { 1461 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1462 DEBUG(dbgs() << " Stub function found\n"); 1463 } else { 1464 // Create a new stub function. 1465 DEBUG(dbgs() << " Create a new stub function\n"); 1466 1467 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1468 uintptr_t StubAlignment = getStubAlignment(); 1469 StubAddress = 1470 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1471 -StubAlignment; 1472 unsigned StubOffset = StubAddress - BaseAddress; 1473 1474 Stubs[Value] = StubOffset; 1475 createStubFunction((uint8_t *)StubAddress); 1476 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1477 Value.Offset); 1478 if (Value.SymbolName) 1479 addRelocationForSymbol(RE, Value.SymbolName); 1480 else 1481 addRelocationForSection(RE, Value.SectionID); 1482 Section.advanceStubOffset(getMaxStubSize()); 1483 } 1484 1485 if (RelType == ELF::R_390_GOTENT) 1486 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1487 Addend); 1488 else 1489 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1490 } else if (Arch == Triple::x86_64) { 1491 if (RelType == ELF::R_X86_64_PLT32) { 1492 // The way the PLT relocations normally work is that the linker allocates 1493 // the 1494 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1495 // entry will then jump to an address provided by the GOT. On first call, 1496 // the 1497 // GOT address will point back into PLT code that resolves the symbol. After 1498 // the first call, the GOT entry points to the actual function. 1499 // 1500 // For local functions we're ignoring all of that here and just replacing 1501 // the PLT32 relocation type with PC32, which will translate the relocation 1502 // into a PC-relative call directly to the function. For external symbols we 1503 // can't be sure the function will be within 2^32 bytes of the call site, so 1504 // we need to create a stub, which calls into the GOT. This case is 1505 // equivalent to the usual PLT implementation except that we use the stub 1506 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1507 // rather than allocating a PLT section. 1508 if (Value.SymbolName) { 1509 // This is a call to an external function. 1510 // Look for an existing stub. 1511 SectionEntry &Section = Sections[SectionID]; 1512 StubMap::const_iterator i = Stubs.find(Value); 1513 uintptr_t StubAddress; 1514 if (i != Stubs.end()) { 1515 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1516 DEBUG(dbgs() << " Stub function found\n"); 1517 } else { 1518 // Create a new stub function (equivalent to a PLT entry). 1519 DEBUG(dbgs() << " Create a new stub function\n"); 1520 1521 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1522 uintptr_t StubAlignment = getStubAlignment(); 1523 StubAddress = 1524 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1525 -StubAlignment; 1526 unsigned StubOffset = StubAddress - BaseAddress; 1527 Stubs[Value] = StubOffset; 1528 createStubFunction((uint8_t *)StubAddress); 1529 1530 // Bump our stub offset counter 1531 Section.advanceStubOffset(getMaxStubSize()); 1532 1533 // Allocate a GOT Entry 1534 uint64_t GOTOffset = allocateGOTEntries(1); 1535 1536 // The load of the GOT address has an addend of -4 1537 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1538 ELF::R_X86_64_PC32); 1539 1540 // Fill in the value of the symbol we're targeting into the GOT 1541 addRelocationForSymbol( 1542 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1543 Value.SymbolName); 1544 } 1545 1546 // Make the target call a call into the stub table. 1547 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1548 Addend); 1549 } else { 1550 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1551 Value.Offset); 1552 addRelocationForSection(RE, Value.SectionID); 1553 } 1554 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1555 RelType == ELF::R_X86_64_GOTPCRELX || 1556 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1557 uint64_t GOTOffset = allocateGOTEntries(1); 1558 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1559 ELF::R_X86_64_PC32); 1560 1561 // Fill in the value of the symbol we're targeting into the GOT 1562 RelocationEntry RE = 1563 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1564 if (Value.SymbolName) 1565 addRelocationForSymbol(RE, Value.SymbolName); 1566 else 1567 addRelocationForSection(RE, Value.SectionID); 1568 } else if (RelType == ELF::R_X86_64_PC32) { 1569 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1570 processSimpleRelocation(SectionID, Offset, RelType, Value); 1571 } else if (RelType == ELF::R_X86_64_PC64) { 1572 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1573 processSimpleRelocation(SectionID, Offset, RelType, Value); 1574 } else { 1575 processSimpleRelocation(SectionID, Offset, RelType, Value); 1576 } 1577 } else { 1578 if (Arch == Triple::x86) { 1579 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1580 } 1581 processSimpleRelocation(SectionID, Offset, RelType, Value); 1582 } 1583 return ++RelI; 1584 } 1585 1586 size_t RuntimeDyldELF::getGOTEntrySize() { 1587 // We don't use the GOT in all of these cases, but it's essentially free 1588 // to put them all here. 1589 size_t Result = 0; 1590 switch (Arch) { 1591 case Triple::x86_64: 1592 case Triple::aarch64: 1593 case Triple::aarch64_be: 1594 case Triple::ppc64: 1595 case Triple::ppc64le: 1596 case Triple::systemz: 1597 Result = sizeof(uint64_t); 1598 break; 1599 case Triple::x86: 1600 case Triple::arm: 1601 case Triple::thumb: 1602 Result = sizeof(uint32_t); 1603 break; 1604 case Triple::mips: 1605 case Triple::mipsel: 1606 case Triple::mips64: 1607 case Triple::mips64el: 1608 if (IsMipsO32ABI || IsMipsN32ABI) 1609 Result = sizeof(uint32_t); 1610 else if (IsMipsN64ABI) 1611 Result = sizeof(uint64_t); 1612 else 1613 llvm_unreachable("Mips ABI not handled"); 1614 break; 1615 default: 1616 llvm_unreachable("Unsupported CPU type!"); 1617 } 1618 return Result; 1619 } 1620 1621 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 1622 if (GOTSectionID == 0) { 1623 GOTSectionID = Sections.size(); 1624 // Reserve a section id. We'll allocate the section later 1625 // once we know the total size 1626 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1627 } 1628 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1629 CurrentGOTIndex += no; 1630 return StartOffset; 1631 } 1632 1633 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 1634 unsigned GOTRelType) { 1635 auto E = GOTOffsetMap.insert({Value, 0}); 1636 if (E.second) { 1637 uint64_t GOTOffset = allocateGOTEntries(1); 1638 1639 // Create relocation for newly created GOT entry 1640 RelocationEntry RE = 1641 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 1642 if (Value.SymbolName) 1643 addRelocationForSymbol(RE, Value.SymbolName); 1644 else 1645 addRelocationForSection(RE, Value.SectionID); 1646 1647 E.first->second = GOTOffset; 1648 } 1649 1650 return E.first->second; 1651 } 1652 1653 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 1654 uint64_t Offset, 1655 uint64_t GOTOffset, 1656 uint32_t Type) { 1657 // Fill in the relative address of the GOT Entry into the stub 1658 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 1659 addRelocationForSection(GOTRE, GOTSectionID); 1660 } 1661 1662 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 1663 uint64_t SymbolOffset, 1664 uint32_t Type) { 1665 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1666 } 1667 1668 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1669 ObjSectionToIDMap &SectionMap) { 1670 if (IsMipsO32ABI) 1671 if (!PendingRelocs.empty()) 1672 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1673 1674 // If necessary, allocate the global offset table 1675 if (GOTSectionID != 0) { 1676 // Allocate memory for the section 1677 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1678 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1679 GOTSectionID, ".got", false); 1680 if (!Addr) 1681 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1682 1683 Sections[GOTSectionID] = 1684 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1685 1686 if (Checker) 1687 Checker->registerSection(Obj.getFileName(), GOTSectionID); 1688 1689 // For now, initialize all GOT entries to zero. We'll fill them in as 1690 // needed when GOT-based relocations are applied. 1691 memset(Addr, 0, TotalSize); 1692 if (IsMipsN32ABI || IsMipsN64ABI) { 1693 // To correctly resolve Mips GOT relocations, we need a mapping from 1694 // object's sections to GOTs. 1695 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1696 SI != SE; ++SI) { 1697 if (SI->relocation_begin() != SI->relocation_end()) { 1698 section_iterator RelocatedSection = SI->getRelocatedSection(); 1699 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1700 assert (i != SectionMap.end()); 1701 SectionToGOTMap[i->second] = GOTSectionID; 1702 } 1703 } 1704 GOTSymbolOffsets.clear(); 1705 } 1706 } 1707 1708 // Look for and record the EH frame section. 1709 ObjSectionToIDMap::iterator i, e; 1710 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1711 const SectionRef &Section = i->first; 1712 StringRef Name; 1713 Section.getName(Name); 1714 if (Name == ".eh_frame") { 1715 UnregisteredEHFrameSections.push_back(i->second); 1716 break; 1717 } 1718 } 1719 1720 GOTSectionID = 0; 1721 CurrentGOTIndex = 0; 1722 1723 return Error::success(); 1724 } 1725 1726 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1727 return Obj.isELF(); 1728 } 1729 1730 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 1731 unsigned RelTy = R.getType(); 1732 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 1733 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 1734 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 1735 1736 if (Arch == Triple::x86_64) 1737 return RelTy == ELF::R_X86_64_GOTPCREL || 1738 RelTy == ELF::R_X86_64_GOTPCRELX || 1739 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 1740 return false; 1741 } 1742 1743 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1744 if (Arch != Triple::x86_64) 1745 return true; // Conservative answer 1746 1747 switch (R.getType()) { 1748 default: 1749 return true; // Conservative answer 1750 1751 1752 case ELF::R_X86_64_GOTPCREL: 1753 case ELF::R_X86_64_GOTPCRELX: 1754 case ELF::R_X86_64_REX_GOTPCRELX: 1755 case ELF::R_X86_64_PC32: 1756 case ELF::R_X86_64_PC64: 1757 case ELF::R_X86_64_64: 1758 // We know that these reloation types won't need a stub function. This list 1759 // can be extended as needed. 1760 return false; 1761 } 1762 } 1763 1764 } // namespace llvm 1765