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_64: { 276 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 277 Value + Addend; 278 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 279 << format("%p\n", Section.getAddressWithOffset(Offset))); 280 break; 281 } 282 case ELF::R_X86_64_32: 283 case ELF::R_X86_64_32S: { 284 Value += Addend; 285 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 286 (Type == ELF::R_X86_64_32S && 287 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 288 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 289 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 290 TruncatedAddr; 291 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 292 << format("%p\n", Section.getAddressWithOffset(Offset))); 293 break; 294 } 295 case ELF::R_X86_64_PC8: { 296 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 297 int64_t RealOffset = Value + Addend - FinalAddress; 298 assert(isInt<8>(RealOffset)); 299 int8_t TruncOffset = (RealOffset & 0xFF); 300 Section.getAddress()[Offset] = TruncOffset; 301 break; 302 } 303 case ELF::R_X86_64_PC32: { 304 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 305 int64_t RealOffset = Value + Addend - FinalAddress; 306 assert(isInt<32>(RealOffset)); 307 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 308 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 309 TruncOffset; 310 break; 311 } 312 case ELF::R_X86_64_PC64: { 313 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 314 int64_t RealOffset = Value + Addend - FinalAddress; 315 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 316 RealOffset; 317 break; 318 } 319 } 320 } 321 322 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 323 uint64_t Offset, uint32_t Value, 324 uint32_t Type, int32_t Addend) { 325 switch (Type) { 326 case ELF::R_386_32: { 327 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 328 Value + Addend; 329 break; 330 } 331 case ELF::R_386_PC32: { 332 uint32_t FinalAddress = 333 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 334 uint32_t RealOffset = Value + Addend - FinalAddress; 335 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 336 RealOffset; 337 break; 338 } 339 default: 340 // There are other relocation types, but it appears these are the 341 // only ones currently used by the LLVM ELF object writer 342 llvm_unreachable("Relocation type not implemented yet!"); 343 break; 344 } 345 } 346 347 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 348 uint64_t Offset, uint64_t Value, 349 uint32_t Type, int64_t Addend) { 350 uint32_t *TargetPtr = 351 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 352 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 353 // Data should use target endian. Code should always use little endian. 354 bool isBE = Arch == Triple::aarch64_be; 355 356 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 357 << format("%llx", Section.getAddressWithOffset(Offset)) 358 << " FinalAddress: 0x" << format("%llx", FinalAddress) 359 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 360 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend) 361 << "\n"); 362 363 switch (Type) { 364 default: 365 llvm_unreachable("Relocation type not implemented yet!"); 366 break; 367 case ELF::R_AARCH64_ABS64: 368 write(isBE, TargetPtr, Value + Addend); 369 break; 370 case ELF::R_AARCH64_PREL32: { 371 uint64_t Result = Value + Addend - FinalAddress; 372 assert(static_cast<int64_t>(Result) >= INT32_MIN && 373 static_cast<int64_t>(Result) <= UINT32_MAX); 374 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 375 break; 376 } 377 case ELF::R_AARCH64_PREL64: 378 write(isBE, TargetPtr, Value + Addend - FinalAddress); 379 break; 380 case ELF::R_AARCH64_CALL26: // fallthrough 381 case ELF::R_AARCH64_JUMP26: { 382 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 383 // calculation. 384 uint64_t BranchImm = Value + Addend - FinalAddress; 385 386 // "Check that -2^27 <= result < 2^27". 387 assert(isInt<28>(BranchImm)); 388 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 389 break; 390 } 391 case ELF::R_AARCH64_MOVW_UABS_G3: 392 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 393 break; 394 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 395 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 396 break; 397 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 398 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 399 break; 400 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 401 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 402 break; 403 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 404 // Operation: Page(S+A) - Page(P) 405 uint64_t Result = 406 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 407 408 // Check that -2^32 <= X < 2^32 409 assert(isInt<33>(Result) && "overflow check failed for relocation"); 410 411 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 412 // from bits 32:12 of X. 413 write32AArch64Addr(TargetPtr, Result >> 12); 414 break; 415 } 416 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 417 // Operation: S + A 418 // Immediate goes in bits 21:10 of LD/ST instruction, taken 419 // from bits 11:0 of X 420 or32AArch64Imm(TargetPtr, Value + Addend); 421 break; 422 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 423 // Operation: S + A 424 // Immediate goes in bits 21:10 of LD/ST instruction, taken 425 // from bits 11:0 of X 426 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 427 break; 428 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 429 // Operation: S + A 430 // Immediate goes in bits 21:10 of LD/ST instruction, taken 431 // from bits 11:1 of X 432 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 433 break; 434 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 435 // Operation: S + A 436 // Immediate goes in bits 21:10 of LD/ST instruction, taken 437 // from bits 11:2 of X 438 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 439 break; 440 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 441 // Operation: S + A 442 // Immediate goes in bits 21:10 of LD/ST instruction, taken 443 // from bits 11:3 of X 444 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 445 break; 446 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 447 // Operation: S + A 448 // Immediate goes in bits 21:10 of LD/ST instruction, taken 449 // from bits 11:4 of X 450 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 451 break; 452 } 453 } 454 455 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 456 uint64_t Offset, uint32_t Value, 457 uint32_t Type, int32_t Addend) { 458 // TODO: Add Thumb relocations. 459 uint32_t *TargetPtr = 460 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 461 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 462 Value += Addend; 463 464 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 465 << Section.getAddressWithOffset(Offset) 466 << " FinalAddress: " << format("%p", FinalAddress) << " Value: " 467 << format("%x", Value) << " Type: " << format("%x", Type) 468 << " Addend: " << format("%x", Addend) << "\n"); 469 470 switch (Type) { 471 default: 472 llvm_unreachable("Not implemented relocation type!"); 473 474 case ELF::R_ARM_NONE: 475 break; 476 // Write a 31bit signed offset 477 case ELF::R_ARM_PREL31: 478 support::ulittle32_t::ref{TargetPtr} = 479 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 480 ((Value - FinalAddress) & ~0x80000000); 481 break; 482 case ELF::R_ARM_TARGET1: 483 case ELF::R_ARM_ABS32: 484 support::ulittle32_t::ref{TargetPtr} = Value; 485 break; 486 // Write first 16 bit of 32 bit value to the mov instruction. 487 // Last 4 bit should be shifted. 488 case ELF::R_ARM_MOVW_ABS_NC: 489 case ELF::R_ARM_MOVT_ABS: 490 if (Type == ELF::R_ARM_MOVW_ABS_NC) 491 Value = Value & 0xFFFF; 492 else if (Type == ELF::R_ARM_MOVT_ABS) 493 Value = (Value >> 16) & 0xFFFF; 494 support::ulittle32_t::ref{TargetPtr} = 495 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 496 (((Value >> 12) & 0xF) << 16); 497 break; 498 // Write 24 bit relative value to the branch instruction. 499 case ELF::R_ARM_PC24: // Fall through. 500 case ELF::R_ARM_CALL: // Fall through. 501 case ELF::R_ARM_JUMP24: 502 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 503 RelValue = (RelValue & 0x03FFFFFC) >> 2; 504 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 505 support::ulittle32_t::ref{TargetPtr} = 506 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 507 break; 508 } 509 } 510 511 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 512 if (Arch == Triple::UnknownArch || 513 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 514 IsMipsO32ABI = false; 515 IsMipsN32ABI = false; 516 IsMipsN64ABI = false; 517 return; 518 } 519 unsigned AbiVariant; 520 Obj.getPlatformFlags(AbiVariant); 521 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 522 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 523 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); 524 } 525 526 // Return the .TOC. section and offset. 527 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 528 ObjSectionToIDMap &LocalSections, 529 RelocationValueRef &Rel) { 530 // Set a default SectionID in case we do not find a TOC section below. 531 // This may happen for references to TOC base base (sym@toc, .odp 532 // relocation) without a .toc directive. In this case just use the 533 // first section (which is usually the .odp) since the code won't 534 // reference the .toc base directly. 535 Rel.SymbolName = nullptr; 536 Rel.SectionID = 0; 537 538 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 539 // order. The TOC starts where the first of these sections starts. 540 for (auto &Section: Obj.sections()) { 541 StringRef SectionName; 542 if (auto EC = Section.getName(SectionName)) 543 return errorCodeToError(EC); 544 545 if (SectionName == ".got" 546 || SectionName == ".toc" 547 || SectionName == ".tocbss" 548 || SectionName == ".plt") { 549 if (auto SectionIDOrErr = 550 findOrEmitSection(Obj, Section, false, LocalSections)) 551 Rel.SectionID = *SectionIDOrErr; 552 else 553 return SectionIDOrErr.takeError(); 554 break; 555 } 556 } 557 558 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 559 // thus permitting a full 64 Kbytes segment. 560 Rel.Addend = 0x8000; 561 562 return Error::success(); 563 } 564 565 // Returns the sections and offset associated with the ODP entry referenced 566 // by Symbol. 567 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 568 ObjSectionToIDMap &LocalSections, 569 RelocationValueRef &Rel) { 570 // Get the ELF symbol value (st_value) to compare with Relocation offset in 571 // .opd entries 572 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 573 si != se; ++si) { 574 section_iterator RelSecI = si->getRelocatedSection(); 575 if (RelSecI == Obj.section_end()) 576 continue; 577 578 StringRef RelSectionName; 579 if (auto EC = RelSecI->getName(RelSectionName)) 580 return errorCodeToError(EC); 581 582 if (RelSectionName != ".opd") 583 continue; 584 585 for (elf_relocation_iterator i = si->relocation_begin(), 586 e = si->relocation_end(); 587 i != e;) { 588 // The R_PPC64_ADDR64 relocation indicates the first field 589 // of a .opd entry 590 uint64_t TypeFunc = i->getType(); 591 if (TypeFunc != ELF::R_PPC64_ADDR64) { 592 ++i; 593 continue; 594 } 595 596 uint64_t TargetSymbolOffset = i->getOffset(); 597 symbol_iterator TargetSymbol = i->getSymbol(); 598 int64_t Addend; 599 if (auto AddendOrErr = i->getAddend()) 600 Addend = *AddendOrErr; 601 else 602 return errorCodeToError(AddendOrErr.getError()); 603 604 ++i; 605 if (i == e) 606 break; 607 608 // Just check if following relocation is a R_PPC64_TOC 609 uint64_t TypeTOC = i->getType(); 610 if (TypeTOC != ELF::R_PPC64_TOC) 611 continue; 612 613 // Finally compares the Symbol value and the target symbol offset 614 // to check if this .opd entry refers to the symbol the relocation 615 // points to. 616 if (Rel.Addend != (int64_t)TargetSymbolOffset) 617 continue; 618 619 section_iterator TSI = Obj.section_end(); 620 if (auto TSIOrErr = TargetSymbol->getSection()) 621 TSI = *TSIOrErr; 622 else 623 return TSIOrErr.takeError(); 624 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 625 626 bool IsCode = TSI->isText(); 627 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 628 LocalSections)) 629 Rel.SectionID = *SectionIDOrErr; 630 else 631 return SectionIDOrErr.takeError(); 632 Rel.Addend = (intptr_t)Addend; 633 return Error::success(); 634 } 635 } 636 llvm_unreachable("Attempting to get address of ODP entry!"); 637 } 638 639 // Relocation masks following the #lo(value), #hi(value), #ha(value), 640 // #higher(value), #highera(value), #highest(value), and #highesta(value) 641 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 642 // document. 643 644 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 645 646 static inline uint16_t applyPPChi(uint64_t value) { 647 return (value >> 16) & 0xffff; 648 } 649 650 static inline uint16_t applyPPCha (uint64_t value) { 651 return ((value + 0x8000) >> 16) & 0xffff; 652 } 653 654 static inline uint16_t applyPPChigher(uint64_t value) { 655 return (value >> 32) & 0xffff; 656 } 657 658 static inline uint16_t applyPPChighera (uint64_t value) { 659 return ((value + 0x8000) >> 32) & 0xffff; 660 } 661 662 static inline uint16_t applyPPChighest(uint64_t value) { 663 return (value >> 48) & 0xffff; 664 } 665 666 static inline uint16_t applyPPChighesta (uint64_t value) { 667 return ((value + 0x8000) >> 48) & 0xffff; 668 } 669 670 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 671 uint64_t Offset, uint64_t Value, 672 uint32_t Type, int64_t Addend) { 673 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 674 switch (Type) { 675 default: 676 llvm_unreachable("Relocation type not implemented yet!"); 677 break; 678 case ELF::R_PPC_ADDR16_LO: 679 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 680 break; 681 case ELF::R_PPC_ADDR16_HI: 682 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 683 break; 684 case ELF::R_PPC_ADDR16_HA: 685 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 686 break; 687 } 688 } 689 690 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 691 uint64_t Offset, uint64_t Value, 692 uint32_t Type, int64_t Addend) { 693 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 694 switch (Type) { 695 default: 696 llvm_unreachable("Relocation type not implemented yet!"); 697 break; 698 case ELF::R_PPC64_ADDR16: 699 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 700 break; 701 case ELF::R_PPC64_ADDR16_DS: 702 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 703 break; 704 case ELF::R_PPC64_ADDR16_LO: 705 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 706 break; 707 case ELF::R_PPC64_ADDR16_LO_DS: 708 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 709 break; 710 case ELF::R_PPC64_ADDR16_HI: 711 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 712 break; 713 case ELF::R_PPC64_ADDR16_HA: 714 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 715 break; 716 case ELF::R_PPC64_ADDR16_HIGHER: 717 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 718 break; 719 case ELF::R_PPC64_ADDR16_HIGHERA: 720 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 721 break; 722 case ELF::R_PPC64_ADDR16_HIGHEST: 723 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 724 break; 725 case ELF::R_PPC64_ADDR16_HIGHESTA: 726 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 727 break; 728 case ELF::R_PPC64_ADDR14: { 729 assert(((Value + Addend) & 3) == 0); 730 // Preserve the AA/LK bits in the branch instruction 731 uint8_t aalk = *(LocalAddress + 3); 732 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 733 } break; 734 case ELF::R_PPC64_REL16_LO: { 735 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 736 uint64_t Delta = Value - FinalAddress + Addend; 737 writeInt16BE(LocalAddress, applyPPClo(Delta)); 738 } break; 739 case ELF::R_PPC64_REL16_HI: { 740 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 741 uint64_t Delta = Value - FinalAddress + Addend; 742 writeInt16BE(LocalAddress, applyPPChi(Delta)); 743 } break; 744 case ELF::R_PPC64_REL16_HA: { 745 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 746 uint64_t Delta = Value - FinalAddress + Addend; 747 writeInt16BE(LocalAddress, applyPPCha(Delta)); 748 } break; 749 case ELF::R_PPC64_ADDR32: { 750 int32_t Result = static_cast<int32_t>(Value + Addend); 751 if (SignExtend32<32>(Result) != Result) 752 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 753 writeInt32BE(LocalAddress, Result); 754 } break; 755 case ELF::R_PPC64_REL24: { 756 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 757 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 758 if (SignExtend32<26>(delta) != delta) 759 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 760 // Generates a 'bl <address>' instruction 761 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); 762 } break; 763 case ELF::R_PPC64_REL32: { 764 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 765 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 766 if (SignExtend32<32>(delta) != delta) 767 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 768 writeInt32BE(LocalAddress, delta); 769 } break; 770 case ELF::R_PPC64_REL64: { 771 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 772 uint64_t Delta = Value - FinalAddress + Addend; 773 writeInt64BE(LocalAddress, Delta); 774 } break; 775 case ELF::R_PPC64_ADDR64: 776 writeInt64BE(LocalAddress, Value + Addend); 777 break; 778 } 779 } 780 781 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 782 uint64_t Offset, uint64_t Value, 783 uint32_t Type, int64_t Addend) { 784 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 785 switch (Type) { 786 default: 787 llvm_unreachable("Relocation type not implemented yet!"); 788 break; 789 case ELF::R_390_PC16DBL: 790 case ELF::R_390_PLT16DBL: { 791 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 792 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 793 writeInt16BE(LocalAddress, Delta / 2); 794 break; 795 } 796 case ELF::R_390_PC32DBL: 797 case ELF::R_390_PLT32DBL: { 798 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 799 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 800 writeInt32BE(LocalAddress, Delta / 2); 801 break; 802 } 803 case ELF::R_390_PC32: { 804 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 805 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 806 writeInt32BE(LocalAddress, Delta); 807 break; 808 } 809 case ELF::R_390_64: 810 writeInt64BE(LocalAddress, Value + Addend); 811 break; 812 case ELF::R_390_PC64: { 813 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 814 writeInt64BE(LocalAddress, Delta); 815 break; 816 } 817 } 818 } 819 820 // The target location for the relocation is described by RE.SectionID and 821 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 822 // SectionEntry has three members describing its location. 823 // SectionEntry::Address is the address at which the section has been loaded 824 // into memory in the current (host) process. SectionEntry::LoadAddress is the 825 // address that the section will have in the target process. 826 // SectionEntry::ObjAddress is the address of the bits for this section in the 827 // original emitted object image (also in the current address space). 828 // 829 // Relocations will be applied as if the section were loaded at 830 // SectionEntry::LoadAddress, but they will be applied at an address based 831 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 832 // Target memory contents if they are required for value calculations. 833 // 834 // The Value parameter here is the load address of the symbol for the 835 // relocation to be applied. For relocations which refer to symbols in the 836 // current object Value will be the LoadAddress of the section in which 837 // the symbol resides (RE.Addend provides additional information about the 838 // symbol location). For external symbols, Value will be the address of the 839 // symbol in the target address space. 840 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 841 uint64_t Value) { 842 const SectionEntry &Section = Sections[RE.SectionID]; 843 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 844 RE.SymOffset, RE.SectionID); 845 } 846 847 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 848 uint64_t Offset, uint64_t Value, 849 uint32_t Type, int64_t Addend, 850 uint64_t SymOffset, SID SectionID) { 851 switch (Arch) { 852 case Triple::x86_64: 853 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 854 break; 855 case Triple::x86: 856 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 857 (uint32_t)(Addend & 0xffffffffL)); 858 break; 859 case Triple::aarch64: 860 case Triple::aarch64_be: 861 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 862 break; 863 case Triple::arm: // Fall through. 864 case Triple::armeb: 865 case Triple::thumb: 866 case Triple::thumbeb: 867 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 868 (uint32_t)(Addend & 0xffffffffL)); 869 break; 870 case Triple::ppc: 871 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 872 break; 873 case Triple::ppc64: // Fall through. 874 case Triple::ppc64le: 875 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 876 break; 877 case Triple::systemz: 878 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 879 break; 880 default: 881 llvm_unreachable("Unsupported CPU type!"); 882 } 883 } 884 885 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 886 return (void *)(Sections[SectionID].getObjAddress() + Offset); 887 } 888 889 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 890 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 891 if (Value.SymbolName) 892 addRelocationForSymbol(RE, Value.SymbolName); 893 else 894 addRelocationForSection(RE, Value.SectionID); 895 } 896 897 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 898 bool IsLocal) const { 899 switch (RelType) { 900 case ELF::R_MICROMIPS_GOT16: 901 if (IsLocal) 902 return ELF::R_MICROMIPS_LO16; 903 break; 904 case ELF::R_MICROMIPS_HI16: 905 return ELF::R_MICROMIPS_LO16; 906 case ELF::R_MIPS_GOT16: 907 if (IsLocal) 908 return ELF::R_MIPS_LO16; 909 break; 910 case ELF::R_MIPS_HI16: 911 return ELF::R_MIPS_LO16; 912 case ELF::R_MIPS_PCHI16: 913 return ELF::R_MIPS_PCLO16; 914 default: 915 break; 916 } 917 return ELF::R_MIPS_NONE; 918 } 919 920 // Sometimes we don't need to create thunk for a branch. 921 // This typically happens when branch target is located 922 // in the same object file. In such case target is either 923 // a weak symbol or symbol in a different executable section. 924 // This function checks if branch target is located in the 925 // same object file and if distance between source and target 926 // fits R_AARCH64_CALL26 relocation. If both conditions are 927 // met, it emits direct jump to the target and returns true. 928 // Otherwise false is returned and thunk is created. 929 bool RuntimeDyldELF::resolveAArch64ShortBranch( 930 unsigned SectionID, relocation_iterator RelI, 931 const RelocationValueRef &Value) { 932 uint64_t Address; 933 if (Value.SymbolName) { 934 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 935 936 // Don't create direct branch for external symbols. 937 if (Loc == GlobalSymbolTable.end()) 938 return false; 939 940 const auto &SymInfo = Loc->second; 941 Address = 942 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 943 SymInfo.getOffset())); 944 } else { 945 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 946 } 947 uint64_t Offset = RelI->getOffset(); 948 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 949 950 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 951 // If distance between source and target is out of range then we should 952 // create thunk. 953 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 954 return false; 955 956 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 957 Value.Addend); 958 959 return true; 960 } 961 962 Expected<relocation_iterator> 963 RuntimeDyldELF::processRelocationRef( 964 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 965 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 966 const auto &Obj = cast<ELFObjectFileBase>(O); 967 uint64_t RelType = RelI->getType(); 968 ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend(); 969 int64_t Addend = AddendOrErr ? *AddendOrErr : 0; 970 elf_symbol_iterator Symbol = RelI->getSymbol(); 971 972 // Obtain the symbol name which is referenced in the relocation 973 StringRef TargetName; 974 if (Symbol != Obj.symbol_end()) { 975 if (auto TargetNameOrErr = Symbol->getName()) 976 TargetName = *TargetNameOrErr; 977 else 978 return TargetNameOrErr.takeError(); 979 } 980 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 981 << " TargetName: " << TargetName << "\n"); 982 RelocationValueRef Value; 983 // First search for the symbol in the local symbol table 984 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 985 986 // Search for the symbol in the global symbol table 987 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 988 if (Symbol != Obj.symbol_end()) { 989 gsi = GlobalSymbolTable.find(TargetName.data()); 990 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 991 if (!SymTypeOrErr) { 992 std::string Buf; 993 raw_string_ostream OS(Buf); 994 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, ""); 995 OS.flush(); 996 report_fatal_error(Buf); 997 } 998 SymType = *SymTypeOrErr; 999 } 1000 if (gsi != GlobalSymbolTable.end()) { 1001 const auto &SymInfo = gsi->second; 1002 Value.SectionID = SymInfo.getSectionID(); 1003 Value.Offset = SymInfo.getOffset(); 1004 Value.Addend = SymInfo.getOffset() + Addend; 1005 } else { 1006 switch (SymType) { 1007 case SymbolRef::ST_Debug: { 1008 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1009 // and can be changed by another developers. Maybe best way is add 1010 // a new symbol type ST_Section to SymbolRef and use it. 1011 auto SectionOrErr = Symbol->getSection(); 1012 if (!SectionOrErr) { 1013 std::string Buf; 1014 raw_string_ostream OS(Buf); 1015 logAllUnhandledErrors(SectionOrErr.takeError(), OS, ""); 1016 OS.flush(); 1017 report_fatal_error(Buf); 1018 } 1019 section_iterator si = *SectionOrErr; 1020 if (si == Obj.section_end()) 1021 llvm_unreachable("Symbol section not found, bad object file format!"); 1022 DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1023 bool isCode = si->isText(); 1024 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1025 ObjSectionToID)) 1026 Value.SectionID = *SectionIDOrErr; 1027 else 1028 return SectionIDOrErr.takeError(); 1029 Value.Addend = Addend; 1030 break; 1031 } 1032 case SymbolRef::ST_Data: 1033 case SymbolRef::ST_Function: 1034 case SymbolRef::ST_Unknown: { 1035 Value.SymbolName = TargetName.data(); 1036 Value.Addend = Addend; 1037 1038 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1039 // will manifest here as a NULL symbol name. 1040 // We can set this as a valid (but empty) symbol name, and rely 1041 // on addRelocationForSymbol to handle this. 1042 if (!Value.SymbolName) 1043 Value.SymbolName = ""; 1044 break; 1045 } 1046 default: 1047 llvm_unreachable("Unresolved symbol type!"); 1048 break; 1049 } 1050 } 1051 1052 uint64_t Offset = RelI->getOffset(); 1053 1054 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1055 << "\n"); 1056 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be) && 1057 (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26)) { 1058 // This is an AArch64 branch relocation, need to use a stub function. 1059 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1060 SectionEntry &Section = Sections[SectionID]; 1061 1062 // Look for an existing stub. 1063 StubMap::const_iterator i = Stubs.find(Value); 1064 if (i != Stubs.end()) { 1065 resolveRelocation(Section, Offset, 1066 (uint64_t)Section.getAddressWithOffset(i->second), 1067 RelType, 0); 1068 DEBUG(dbgs() << " Stub function found\n"); 1069 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1070 // Create a new stub function. 1071 DEBUG(dbgs() << " Create a new stub function\n"); 1072 Stubs[Value] = Section.getStubOffset(); 1073 uint8_t *StubTargetAddr = createStubFunction( 1074 Section.getAddressWithOffset(Section.getStubOffset())); 1075 1076 RelocationEntry REmovz_g3(SectionID, 1077 StubTargetAddr - Section.getAddress(), 1078 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1079 RelocationEntry REmovk_g2(SectionID, StubTargetAddr - 1080 Section.getAddress() + 4, 1081 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1082 RelocationEntry REmovk_g1(SectionID, StubTargetAddr - 1083 Section.getAddress() + 8, 1084 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1085 RelocationEntry REmovk_g0(SectionID, StubTargetAddr - 1086 Section.getAddress() + 12, 1087 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1088 1089 if (Value.SymbolName) { 1090 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1091 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1092 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1093 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1094 } else { 1095 addRelocationForSection(REmovz_g3, Value.SectionID); 1096 addRelocationForSection(REmovk_g2, Value.SectionID); 1097 addRelocationForSection(REmovk_g1, Value.SectionID); 1098 addRelocationForSection(REmovk_g0, Value.SectionID); 1099 } 1100 resolveRelocation(Section, Offset, 1101 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1102 Section.getStubOffset())), 1103 RelType, 0); 1104 Section.advanceStubOffset(getMaxStubSize()); 1105 } 1106 } else if (Arch == Triple::arm) { 1107 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1108 RelType == ELF::R_ARM_JUMP24) { 1109 // This is an ARM branch relocation, need to use a stub function. 1110 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1111 SectionEntry &Section = Sections[SectionID]; 1112 1113 // Look for an existing stub. 1114 StubMap::const_iterator i = Stubs.find(Value); 1115 if (i != Stubs.end()) { 1116 resolveRelocation( 1117 Section, Offset, 1118 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1119 RelType, 0); 1120 DEBUG(dbgs() << " Stub function found\n"); 1121 } else { 1122 // Create a new stub function. 1123 DEBUG(dbgs() << " Create a new stub function\n"); 1124 Stubs[Value] = Section.getStubOffset(); 1125 uint8_t *StubTargetAddr = createStubFunction( 1126 Section.getAddressWithOffset(Section.getStubOffset())); 1127 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1128 ELF::R_ARM_ABS32, Value.Addend); 1129 if (Value.SymbolName) 1130 addRelocationForSymbol(RE, Value.SymbolName); 1131 else 1132 addRelocationForSection(RE, Value.SectionID); 1133 1134 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1135 Section.getAddressWithOffset( 1136 Section.getStubOffset())), 1137 RelType, 0); 1138 Section.advanceStubOffset(getMaxStubSize()); 1139 } 1140 } else { 1141 uint32_t *Placeholder = 1142 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1143 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1144 RelType == ELF::R_ARM_ABS32) { 1145 Value.Addend += *Placeholder; 1146 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1147 // See ELF for ARM documentation 1148 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1149 } 1150 processSimpleRelocation(SectionID, Offset, RelType, Value); 1151 } 1152 } else if (IsMipsO32ABI) { 1153 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1154 computePlaceholderAddress(SectionID, Offset)); 1155 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1156 if (RelType == ELF::R_MIPS_26) { 1157 // This is an Mips branch relocation, need to use a stub function. 1158 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1159 SectionEntry &Section = Sections[SectionID]; 1160 1161 // Extract the addend from the instruction. 1162 // We shift up by two since the Value will be down shifted again 1163 // when applying the relocation. 1164 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1165 1166 Value.Addend += Addend; 1167 1168 // Look up for existing stub. 1169 StubMap::const_iterator i = Stubs.find(Value); 1170 if (i != Stubs.end()) { 1171 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1172 addRelocationForSection(RE, SectionID); 1173 DEBUG(dbgs() << " Stub function found\n"); 1174 } else { 1175 // Create a new stub function. 1176 DEBUG(dbgs() << " Create a new stub function\n"); 1177 Stubs[Value] = Section.getStubOffset(); 1178 1179 unsigned AbiVariant; 1180 O.getPlatformFlags(AbiVariant); 1181 1182 uint8_t *StubTargetAddr = createStubFunction( 1183 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1184 1185 // Creating Hi and Lo relocations for the filled stub instructions. 1186 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1187 ELF::R_MIPS_HI16, Value.Addend); 1188 RelocationEntry RELo(SectionID, 1189 StubTargetAddr - Section.getAddress() + 4, 1190 ELF::R_MIPS_LO16, Value.Addend); 1191 1192 if (Value.SymbolName) { 1193 addRelocationForSymbol(REHi, Value.SymbolName); 1194 addRelocationForSymbol(RELo, Value.SymbolName); 1195 } 1196 else { 1197 addRelocationForSection(REHi, Value.SectionID); 1198 addRelocationForSection(RELo, Value.SectionID); 1199 } 1200 1201 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1202 addRelocationForSection(RE, SectionID); 1203 Section.advanceStubOffset(getMaxStubSize()); 1204 } 1205 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1206 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1207 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1208 PendingRelocs.push_back(std::make_pair(Value, RE)); 1209 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1210 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1211 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1212 const RelocationValueRef &MatchingValue = I->first; 1213 RelocationEntry &Reloc = I->second; 1214 if (MatchingValue == Value && 1215 RelType == getMatchingLoRelocation(Reloc.RelType) && 1216 SectionID == Reloc.SectionID) { 1217 Reloc.Addend += Addend; 1218 if (Value.SymbolName) 1219 addRelocationForSymbol(Reloc, Value.SymbolName); 1220 else 1221 addRelocationForSection(Reloc, Value.SectionID); 1222 I = PendingRelocs.erase(I); 1223 } else 1224 ++I; 1225 } 1226 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1227 if (Value.SymbolName) 1228 addRelocationForSymbol(RE, Value.SymbolName); 1229 else 1230 addRelocationForSection(RE, Value.SectionID); 1231 } else { 1232 if (RelType == ELF::R_MIPS_32) 1233 Value.Addend += Opcode; 1234 else if (RelType == ELF::R_MIPS_PC16) 1235 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1236 else if (RelType == ELF::R_MIPS_PC19_S2) 1237 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1238 else if (RelType == ELF::R_MIPS_PC21_S2) 1239 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1240 else if (RelType == ELF::R_MIPS_PC26_S2) 1241 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1242 processSimpleRelocation(SectionID, Offset, RelType, Value); 1243 } 1244 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1245 uint32_t r_type = RelType & 0xff; 1246 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1247 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1248 || r_type == ELF::R_MIPS_GOT_DISP) { 1249 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1250 if (i != GOTSymbolOffsets.end()) 1251 RE.SymOffset = i->second; 1252 else { 1253 RE.SymOffset = allocateGOTEntries(SectionID, 1); 1254 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1255 } 1256 } 1257 if (Value.SymbolName) 1258 addRelocationForSymbol(RE, Value.SymbolName); 1259 else 1260 addRelocationForSection(RE, Value.SectionID); 1261 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1262 if (RelType == ELF::R_PPC64_REL24) { 1263 // Determine ABI variant in use for this object. 1264 unsigned AbiVariant; 1265 Obj.getPlatformFlags(AbiVariant); 1266 AbiVariant &= ELF::EF_PPC64_ABI; 1267 // A PPC branch relocation will need a stub function if the target is 1268 // an external symbol (Symbol::ST_Unknown) or if the target address 1269 // is not within the signed 24-bits branch address. 1270 SectionEntry &Section = Sections[SectionID]; 1271 uint8_t *Target = Section.getAddressWithOffset(Offset); 1272 bool RangeOverflow = false; 1273 if (SymType != SymbolRef::ST_Unknown) { 1274 if (AbiVariant != 2) { 1275 // In the ELFv1 ABI, a function call may point to the .opd entry, 1276 // so the final symbol value is calculated based on the relocation 1277 // values in the .opd section. 1278 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1279 return std::move(Err); 1280 } else { 1281 // In the ELFv2 ABI, a function symbol may provide a local entry 1282 // point, which must be used for direct calls. 1283 uint8_t SymOther = Symbol->getOther(); 1284 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1285 } 1286 uint8_t *RelocTarget = 1287 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1288 int32_t delta = static_cast<int32_t>(Target - RelocTarget); 1289 // If it is within 26-bits branch range, just set the branch target 1290 if (SignExtend32<26>(delta) == delta) { 1291 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1292 if (Value.SymbolName) 1293 addRelocationForSymbol(RE, Value.SymbolName); 1294 else 1295 addRelocationForSection(RE, Value.SectionID); 1296 } else { 1297 RangeOverflow = true; 1298 } 1299 } 1300 if (SymType == SymbolRef::ST_Unknown || RangeOverflow) { 1301 // It is an external symbol (SymbolRef::ST_Unknown) or within a range 1302 // larger than 24-bits. 1303 StubMap::const_iterator i = Stubs.find(Value); 1304 if (i != Stubs.end()) { 1305 // Symbol function stub already created, just relocate to it 1306 resolveRelocation(Section, Offset, 1307 reinterpret_cast<uint64_t>( 1308 Section.getAddressWithOffset(i->second)), 1309 RelType, 0); 1310 DEBUG(dbgs() << " Stub function found\n"); 1311 } else { 1312 // Create a new stub function. 1313 DEBUG(dbgs() << " Create a new stub function\n"); 1314 Stubs[Value] = Section.getStubOffset(); 1315 uint8_t *StubTargetAddr = createStubFunction( 1316 Section.getAddressWithOffset(Section.getStubOffset()), 1317 AbiVariant); 1318 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1319 ELF::R_PPC64_ADDR64, Value.Addend); 1320 1321 // Generates the 64-bits address loads as exemplified in section 1322 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1323 // apply to the low part of the instructions, so we have to update 1324 // the offset according to the target endianness. 1325 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1326 if (!IsTargetLittleEndian) 1327 StubRelocOffset += 2; 1328 1329 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1330 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1331 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1332 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1333 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1334 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1335 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1336 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1337 1338 if (Value.SymbolName) { 1339 addRelocationForSymbol(REhst, Value.SymbolName); 1340 addRelocationForSymbol(REhr, Value.SymbolName); 1341 addRelocationForSymbol(REh, Value.SymbolName); 1342 addRelocationForSymbol(REl, Value.SymbolName); 1343 } else { 1344 addRelocationForSection(REhst, Value.SectionID); 1345 addRelocationForSection(REhr, Value.SectionID); 1346 addRelocationForSection(REh, Value.SectionID); 1347 addRelocationForSection(REl, Value.SectionID); 1348 } 1349 1350 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1351 Section.getAddressWithOffset( 1352 Section.getStubOffset())), 1353 RelType, 0); 1354 Section.advanceStubOffset(getMaxStubSize()); 1355 } 1356 if (SymType == SymbolRef::ST_Unknown) { 1357 // Restore the TOC for external calls 1358 if (AbiVariant == 2) 1359 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1) 1360 else 1361 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1362 } 1363 } 1364 } else if (RelType == ELF::R_PPC64_TOC16 || 1365 RelType == ELF::R_PPC64_TOC16_DS || 1366 RelType == ELF::R_PPC64_TOC16_LO || 1367 RelType == ELF::R_PPC64_TOC16_LO_DS || 1368 RelType == ELF::R_PPC64_TOC16_HI || 1369 RelType == ELF::R_PPC64_TOC16_HA) { 1370 // These relocations are supposed to subtract the TOC address from 1371 // the final value. This does not fit cleanly into the RuntimeDyld 1372 // scheme, since there may be *two* sections involved in determining 1373 // the relocation value (the section of the symbol referred to by the 1374 // relocation, and the TOC section associated with the current module). 1375 // 1376 // Fortunately, these relocations are currently only ever generated 1377 // referring to symbols that themselves reside in the TOC, which means 1378 // that the two sections are actually the same. Thus they cancel out 1379 // and we can immediately resolve the relocation right now. 1380 switch (RelType) { 1381 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1382 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1383 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1384 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1385 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1386 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1387 default: llvm_unreachable("Wrong relocation type."); 1388 } 1389 1390 RelocationValueRef TOCValue; 1391 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1392 return std::move(Err); 1393 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1394 llvm_unreachable("Unsupported TOC relocation."); 1395 Value.Addend -= TOCValue.Addend; 1396 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1397 } else { 1398 // There are two ways to refer to the TOC address directly: either 1399 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1400 // ignored), or via any relocation that refers to the magic ".TOC." 1401 // symbols (in which case the addend is respected). 1402 if (RelType == ELF::R_PPC64_TOC) { 1403 RelType = ELF::R_PPC64_ADDR64; 1404 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1405 return std::move(Err); 1406 } else if (TargetName == ".TOC.") { 1407 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1408 return std::move(Err); 1409 Value.Addend += Addend; 1410 } 1411 1412 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1413 1414 if (Value.SymbolName) 1415 addRelocationForSymbol(RE, Value.SymbolName); 1416 else 1417 addRelocationForSection(RE, Value.SectionID); 1418 } 1419 } else if (Arch == Triple::systemz && 1420 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1421 // Create function stubs for both PLT and GOT references, regardless of 1422 // whether the GOT reference is to data or code. The stub contains the 1423 // full address of the symbol, as needed by GOT references, and the 1424 // executable part only adds an overhead of 8 bytes. 1425 // 1426 // We could try to conserve space by allocating the code and data 1427 // parts of the stub separately. However, as things stand, we allocate 1428 // a stub for every relocation, so using a GOT in JIT code should be 1429 // no less space efficient than using an explicit constant pool. 1430 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1431 SectionEntry &Section = Sections[SectionID]; 1432 1433 // Look for an existing stub. 1434 StubMap::const_iterator i = Stubs.find(Value); 1435 uintptr_t StubAddress; 1436 if (i != Stubs.end()) { 1437 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1438 DEBUG(dbgs() << " Stub function found\n"); 1439 } else { 1440 // Create a new stub function. 1441 DEBUG(dbgs() << " Create a new stub function\n"); 1442 1443 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1444 uintptr_t StubAlignment = getStubAlignment(); 1445 StubAddress = 1446 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1447 -StubAlignment; 1448 unsigned StubOffset = StubAddress - BaseAddress; 1449 1450 Stubs[Value] = StubOffset; 1451 createStubFunction((uint8_t *)StubAddress); 1452 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1453 Value.Offset); 1454 if (Value.SymbolName) 1455 addRelocationForSymbol(RE, Value.SymbolName); 1456 else 1457 addRelocationForSection(RE, Value.SectionID); 1458 Section.advanceStubOffset(getMaxStubSize()); 1459 } 1460 1461 if (RelType == ELF::R_390_GOTENT) 1462 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1463 Addend); 1464 else 1465 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1466 } else if (Arch == Triple::x86_64) { 1467 if (RelType == ELF::R_X86_64_PLT32) { 1468 // The way the PLT relocations normally work is that the linker allocates 1469 // the 1470 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1471 // entry will then jump to an address provided by the GOT. On first call, 1472 // the 1473 // GOT address will point back into PLT code that resolves the symbol. After 1474 // the first call, the GOT entry points to the actual function. 1475 // 1476 // For local functions we're ignoring all of that here and just replacing 1477 // the PLT32 relocation type with PC32, which will translate the relocation 1478 // into a PC-relative call directly to the function. For external symbols we 1479 // can't be sure the function will be within 2^32 bytes of the call site, so 1480 // we need to create a stub, which calls into the GOT. This case is 1481 // equivalent to the usual PLT implementation except that we use the stub 1482 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1483 // rather than allocating a PLT section. 1484 if (Value.SymbolName) { 1485 // This is a call to an external function. 1486 // Look for an existing stub. 1487 SectionEntry &Section = Sections[SectionID]; 1488 StubMap::const_iterator i = Stubs.find(Value); 1489 uintptr_t StubAddress; 1490 if (i != Stubs.end()) { 1491 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1492 DEBUG(dbgs() << " Stub function found\n"); 1493 } else { 1494 // Create a new stub function (equivalent to a PLT entry). 1495 DEBUG(dbgs() << " Create a new stub function\n"); 1496 1497 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1498 uintptr_t StubAlignment = getStubAlignment(); 1499 StubAddress = 1500 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1501 -StubAlignment; 1502 unsigned StubOffset = StubAddress - BaseAddress; 1503 Stubs[Value] = StubOffset; 1504 createStubFunction((uint8_t *)StubAddress); 1505 1506 // Bump our stub offset counter 1507 Section.advanceStubOffset(getMaxStubSize()); 1508 1509 // Allocate a GOT Entry 1510 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1); 1511 1512 // The load of the GOT address has an addend of -4 1513 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4); 1514 1515 // Fill in the value of the symbol we're targeting into the GOT 1516 addRelocationForSymbol( 1517 computeGOTOffsetRE(SectionID, GOTOffset, 0, ELF::R_X86_64_64), 1518 Value.SymbolName); 1519 } 1520 1521 // Make the target call a call into the stub table. 1522 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1523 Addend); 1524 } else { 1525 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1526 Value.Offset); 1527 addRelocationForSection(RE, Value.SectionID); 1528 } 1529 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1530 RelType == ELF::R_X86_64_GOTPCRELX || 1531 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1532 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1); 1533 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend); 1534 1535 // Fill in the value of the symbol we're targeting into the GOT 1536 RelocationEntry RE = computeGOTOffsetRE(SectionID, GOTOffset, Value.Offset, ELF::R_X86_64_64); 1537 if (Value.SymbolName) 1538 addRelocationForSymbol(RE, Value.SymbolName); 1539 else 1540 addRelocationForSection(RE, Value.SectionID); 1541 } else if (RelType == ELF::R_X86_64_PC32) { 1542 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1543 processSimpleRelocation(SectionID, Offset, RelType, Value); 1544 } else if (RelType == ELF::R_X86_64_PC64) { 1545 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1546 processSimpleRelocation(SectionID, Offset, RelType, Value); 1547 } else { 1548 processSimpleRelocation(SectionID, Offset, RelType, Value); 1549 } 1550 } else { 1551 if (Arch == Triple::x86) { 1552 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1553 } 1554 processSimpleRelocation(SectionID, Offset, RelType, Value); 1555 } 1556 return ++RelI; 1557 } 1558 1559 size_t RuntimeDyldELF::getGOTEntrySize() { 1560 // We don't use the GOT in all of these cases, but it's essentially free 1561 // to put them all here. 1562 size_t Result = 0; 1563 switch (Arch) { 1564 case Triple::x86_64: 1565 case Triple::aarch64: 1566 case Triple::aarch64_be: 1567 case Triple::ppc64: 1568 case Triple::ppc64le: 1569 case Triple::systemz: 1570 Result = sizeof(uint64_t); 1571 break; 1572 case Triple::x86: 1573 case Triple::arm: 1574 case Triple::thumb: 1575 Result = sizeof(uint32_t); 1576 break; 1577 case Triple::mips: 1578 case Triple::mipsel: 1579 case Triple::mips64: 1580 case Triple::mips64el: 1581 if (IsMipsO32ABI || IsMipsN32ABI) 1582 Result = sizeof(uint32_t); 1583 else if (IsMipsN64ABI) 1584 Result = sizeof(uint64_t); 1585 else 1586 llvm_unreachable("Mips ABI not handled"); 1587 break; 1588 default: 1589 llvm_unreachable("Unsupported CPU type!"); 1590 } 1591 return Result; 1592 } 1593 1594 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned SectionID, unsigned no) 1595 { 1596 (void)SectionID; // The GOT Section is the same for all section in the object file 1597 if (GOTSectionID == 0) { 1598 GOTSectionID = Sections.size(); 1599 // Reserve a section id. We'll allocate the section later 1600 // once we know the total size 1601 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1602 } 1603 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1604 CurrentGOTIndex += no; 1605 return StartOffset; 1606 } 1607 1608 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, uint64_t GOTOffset) 1609 { 1610 // Fill in the relative address of the GOT Entry into the stub 1611 RelocationEntry GOTRE(SectionID, Offset, ELF::R_X86_64_PC32, GOTOffset); 1612 addRelocationForSection(GOTRE, GOTSectionID); 1613 } 1614 1615 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(unsigned SectionID, uint64_t GOTOffset, uint64_t SymbolOffset, 1616 uint32_t Type) 1617 { 1618 (void)SectionID; // The GOT Section is the same for all section in the object file 1619 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1620 } 1621 1622 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1623 ObjSectionToIDMap &SectionMap) { 1624 if (IsMipsO32ABI) 1625 if (!PendingRelocs.empty()) 1626 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1627 1628 // If necessary, allocate the global offset table 1629 if (GOTSectionID != 0) { 1630 // Allocate memory for the section 1631 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1632 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1633 GOTSectionID, ".got", false); 1634 if (!Addr) 1635 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1636 1637 Sections[GOTSectionID] = 1638 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1639 1640 if (Checker) 1641 Checker->registerSection(Obj.getFileName(), GOTSectionID); 1642 1643 // For now, initialize all GOT entries to zero. We'll fill them in as 1644 // needed when GOT-based relocations are applied. 1645 memset(Addr, 0, TotalSize); 1646 if (IsMipsN32ABI || IsMipsN64ABI) { 1647 // To correctly resolve Mips GOT relocations, we need a mapping from 1648 // object's sections to GOTs. 1649 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1650 SI != SE; ++SI) { 1651 if (SI->relocation_begin() != SI->relocation_end()) { 1652 section_iterator RelocatedSection = SI->getRelocatedSection(); 1653 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1654 assert (i != SectionMap.end()); 1655 SectionToGOTMap[i->second] = GOTSectionID; 1656 } 1657 } 1658 GOTSymbolOffsets.clear(); 1659 } 1660 } 1661 1662 // Look for and record the EH frame section. 1663 ObjSectionToIDMap::iterator i, e; 1664 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1665 const SectionRef &Section = i->first; 1666 StringRef Name; 1667 Section.getName(Name); 1668 if (Name == ".eh_frame") { 1669 UnregisteredEHFrameSections.push_back(i->second); 1670 break; 1671 } 1672 } 1673 1674 GOTSectionID = 0; 1675 CurrentGOTIndex = 0; 1676 1677 return Error::success(); 1678 } 1679 1680 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1681 return Obj.isELF(); 1682 } 1683 1684 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1685 if (Arch != Triple::x86_64) 1686 return true; // Conservative answer 1687 1688 switch (R.getType()) { 1689 default: 1690 return true; // Conservative answer 1691 1692 1693 case ELF::R_X86_64_GOTPCREL: 1694 case ELF::R_X86_64_GOTPCRELX: 1695 case ELF::R_X86_64_REX_GOTPCRELX: 1696 case ELF::R_X86_64_PC32: 1697 case ELF::R_X86_64_PC64: 1698 case ELF::R_X86_64_64: 1699 // We know that these reloation types won't need a stub function. This list 1700 // can be extended as needed. 1701 return false; 1702 } 1703 } 1704 1705 } // namespace llvm 1706