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/BinaryFormat/ELF.h" 22 #include "llvm/MC/MCStreamer.h" 23 #include "llvm/Object/ELFObjectFile.h" 24 #include "llvm/Object/ObjectFile.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 } 225 UnregisteredEHFrameSections.clear(); 226 } 227 228 std::unique_ptr<RuntimeDyldELF> 229 llvm::RuntimeDyldELF::create(Triple::ArchType Arch, 230 RuntimeDyld::MemoryManager &MemMgr, 231 JITSymbolResolver &Resolver) { 232 switch (Arch) { 233 default: 234 return make_unique<RuntimeDyldELF>(MemMgr, Resolver); 235 case Triple::mips: 236 case Triple::mipsel: 237 case Triple::mips64: 238 case Triple::mips64el: 239 return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); 240 } 241 } 242 243 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 244 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 245 if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) 246 return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); 247 else { 248 HasError = true; 249 raw_string_ostream ErrStream(ErrorStr); 250 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, ""); 251 return nullptr; 252 } 253 } 254 255 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 256 uint64_t Offset, uint64_t Value, 257 uint32_t Type, int64_t Addend, 258 uint64_t SymOffset) { 259 switch (Type) { 260 default: 261 llvm_unreachable("Relocation type not implemented yet!"); 262 break; 263 case ELF::R_X86_64_NONE: 264 break; 265 case ELF::R_X86_64_64: { 266 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 267 Value + Addend; 268 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 269 << format("%p\n", Section.getAddressWithOffset(Offset))); 270 break; 271 } 272 case ELF::R_X86_64_32: 273 case ELF::R_X86_64_32S: { 274 Value += Addend; 275 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 276 (Type == ELF::R_X86_64_32S && 277 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 278 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 279 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 280 TruncatedAddr; 281 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 282 << format("%p\n", Section.getAddressWithOffset(Offset))); 283 break; 284 } 285 case ELF::R_X86_64_PC8: { 286 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 287 int64_t RealOffset = Value + Addend - FinalAddress; 288 assert(isInt<8>(RealOffset)); 289 int8_t TruncOffset = (RealOffset & 0xFF); 290 Section.getAddress()[Offset] = TruncOffset; 291 break; 292 } 293 case ELF::R_X86_64_PC32: { 294 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 295 int64_t RealOffset = Value + Addend - FinalAddress; 296 assert(isInt<32>(RealOffset)); 297 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 298 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 299 TruncOffset; 300 break; 301 } 302 case ELF::R_X86_64_PC64: { 303 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 304 int64_t RealOffset = Value + Addend - FinalAddress; 305 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 306 RealOffset; 307 break; 308 } 309 } 310 } 311 312 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 313 uint64_t Offset, uint32_t Value, 314 uint32_t Type, int32_t Addend) { 315 switch (Type) { 316 case ELF::R_386_32: { 317 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 318 Value + Addend; 319 break; 320 } 321 case ELF::R_386_PC32: { 322 uint32_t FinalAddress = 323 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 324 uint32_t RealOffset = Value + Addend - FinalAddress; 325 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 326 RealOffset; 327 break; 328 } 329 default: 330 // There are other relocation types, but it appears these are the 331 // only ones currently used by the LLVM ELF object writer 332 llvm_unreachable("Relocation type not implemented yet!"); 333 break; 334 } 335 } 336 337 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 338 uint64_t Offset, uint64_t Value, 339 uint32_t Type, int64_t Addend) { 340 uint32_t *TargetPtr = 341 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 342 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 343 // Data should use target endian. Code should always use little endian. 344 bool isBE = Arch == Triple::aarch64_be; 345 346 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 347 << format("%llx", Section.getAddressWithOffset(Offset)) 348 << " FinalAddress: 0x" << format("%llx", FinalAddress) 349 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 350 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend) 351 << "\n"); 352 353 switch (Type) { 354 default: 355 llvm_unreachable("Relocation type not implemented yet!"); 356 break; 357 case ELF::R_AARCH64_ABS64: 358 write(isBE, TargetPtr, Value + Addend); 359 break; 360 case ELF::R_AARCH64_PREL32: { 361 uint64_t Result = Value + Addend - FinalAddress; 362 assert(static_cast<int64_t>(Result) >= INT32_MIN && 363 static_cast<int64_t>(Result) <= UINT32_MAX); 364 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 365 break; 366 } 367 case ELF::R_AARCH64_PREL64: 368 write(isBE, TargetPtr, Value + Addend - FinalAddress); 369 break; 370 case ELF::R_AARCH64_CALL26: // fallthrough 371 case ELF::R_AARCH64_JUMP26: { 372 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 373 // calculation. 374 uint64_t BranchImm = Value + Addend - FinalAddress; 375 376 // "Check that -2^27 <= result < 2^27". 377 assert(isInt<28>(BranchImm)); 378 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 379 break; 380 } 381 case ELF::R_AARCH64_MOVW_UABS_G3: 382 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 383 break; 384 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 385 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 386 break; 387 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 388 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 389 break; 390 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 391 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 392 break; 393 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 394 // Operation: Page(S+A) - Page(P) 395 uint64_t Result = 396 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 397 398 // Check that -2^32 <= X < 2^32 399 assert(isInt<33>(Result) && "overflow check failed for relocation"); 400 401 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 402 // from bits 32:12 of X. 403 write32AArch64Addr(TargetPtr, Result >> 12); 404 break; 405 } 406 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 407 // Operation: S + A 408 // Immediate goes in bits 21:10 of LD/ST instruction, taken 409 // from bits 11:0 of X 410 or32AArch64Imm(TargetPtr, Value + Addend); 411 break; 412 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 413 // Operation: S + A 414 // Immediate goes in bits 21:10 of LD/ST instruction, taken 415 // from bits 11:0 of X 416 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 417 break; 418 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 419 // Operation: S + A 420 // Immediate goes in bits 21:10 of LD/ST instruction, taken 421 // from bits 11:1 of X 422 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 423 break; 424 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 425 // Operation: S + A 426 // Immediate goes in bits 21:10 of LD/ST instruction, taken 427 // from bits 11:2 of X 428 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 429 break; 430 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 431 // Operation: S + A 432 // Immediate goes in bits 21:10 of LD/ST instruction, taken 433 // from bits 11:3 of X 434 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 435 break; 436 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 437 // Operation: S + A 438 // Immediate goes in bits 21:10 of LD/ST instruction, taken 439 // from bits 11:4 of X 440 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 441 break; 442 } 443 } 444 445 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 446 uint64_t Offset, uint32_t Value, 447 uint32_t Type, int32_t Addend) { 448 // TODO: Add Thumb relocations. 449 uint32_t *TargetPtr = 450 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 451 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 452 Value += Addend; 453 454 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 455 << Section.getAddressWithOffset(Offset) 456 << " FinalAddress: " << format("%p", FinalAddress) << " Value: " 457 << format("%x", Value) << " Type: " << format("%x", Type) 458 << " Addend: " << format("%x", Addend) << "\n"); 459 460 switch (Type) { 461 default: 462 llvm_unreachable("Not implemented relocation type!"); 463 464 case ELF::R_ARM_NONE: 465 break; 466 // Write a 31bit signed offset 467 case ELF::R_ARM_PREL31: 468 support::ulittle32_t::ref{TargetPtr} = 469 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 470 ((Value - FinalAddress) & ~0x80000000); 471 break; 472 case ELF::R_ARM_TARGET1: 473 case ELF::R_ARM_ABS32: 474 support::ulittle32_t::ref{TargetPtr} = Value; 475 break; 476 // Write first 16 bit of 32 bit value to the mov instruction. 477 // Last 4 bit should be shifted. 478 case ELF::R_ARM_MOVW_ABS_NC: 479 case ELF::R_ARM_MOVT_ABS: 480 if (Type == ELF::R_ARM_MOVW_ABS_NC) 481 Value = Value & 0xFFFF; 482 else if (Type == ELF::R_ARM_MOVT_ABS) 483 Value = (Value >> 16) & 0xFFFF; 484 support::ulittle32_t::ref{TargetPtr} = 485 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 486 (((Value >> 12) & 0xF) << 16); 487 break; 488 // Write 24 bit relative value to the branch instruction. 489 case ELF::R_ARM_PC24: // Fall through. 490 case ELF::R_ARM_CALL: // Fall through. 491 case ELF::R_ARM_JUMP24: 492 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 493 RelValue = (RelValue & 0x03FFFFFC) >> 2; 494 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 495 support::ulittle32_t::ref{TargetPtr} = 496 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 497 break; 498 } 499 } 500 501 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 502 if (Arch == Triple::UnknownArch || 503 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 504 IsMipsO32ABI = false; 505 IsMipsN32ABI = false; 506 IsMipsN64ABI = false; 507 return; 508 } 509 unsigned AbiVariant; 510 Obj.getPlatformFlags(AbiVariant); 511 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 512 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 513 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); 514 } 515 516 // Return the .TOC. section and offset. 517 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 518 ObjSectionToIDMap &LocalSections, 519 RelocationValueRef &Rel) { 520 // Set a default SectionID in case we do not find a TOC section below. 521 // This may happen for references to TOC base base (sym@toc, .odp 522 // relocation) without a .toc directive. In this case just use the 523 // first section (which is usually the .odp) since the code won't 524 // reference the .toc base directly. 525 Rel.SymbolName = nullptr; 526 Rel.SectionID = 0; 527 528 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 529 // order. The TOC starts where the first of these sections starts. 530 for (auto &Section: Obj.sections()) { 531 StringRef SectionName; 532 if (auto EC = Section.getName(SectionName)) 533 return errorCodeToError(EC); 534 535 if (SectionName == ".got" 536 || SectionName == ".toc" 537 || SectionName == ".tocbss" 538 || SectionName == ".plt") { 539 if (auto SectionIDOrErr = 540 findOrEmitSection(Obj, Section, false, LocalSections)) 541 Rel.SectionID = *SectionIDOrErr; 542 else 543 return SectionIDOrErr.takeError(); 544 break; 545 } 546 } 547 548 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 549 // thus permitting a full 64 Kbytes segment. 550 Rel.Addend = 0x8000; 551 552 return Error::success(); 553 } 554 555 // Returns the sections and offset associated with the ODP entry referenced 556 // by Symbol. 557 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 558 ObjSectionToIDMap &LocalSections, 559 RelocationValueRef &Rel) { 560 // Get the ELF symbol value (st_value) to compare with Relocation offset in 561 // .opd entries 562 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 563 si != se; ++si) { 564 section_iterator RelSecI = si->getRelocatedSection(); 565 if (RelSecI == Obj.section_end()) 566 continue; 567 568 StringRef RelSectionName; 569 if (auto EC = RelSecI->getName(RelSectionName)) 570 return errorCodeToError(EC); 571 572 if (RelSectionName != ".opd") 573 continue; 574 575 for (elf_relocation_iterator i = si->relocation_begin(), 576 e = si->relocation_end(); 577 i != e;) { 578 // The R_PPC64_ADDR64 relocation indicates the first field 579 // of a .opd entry 580 uint64_t TypeFunc = i->getType(); 581 if (TypeFunc != ELF::R_PPC64_ADDR64) { 582 ++i; 583 continue; 584 } 585 586 uint64_t TargetSymbolOffset = i->getOffset(); 587 symbol_iterator TargetSymbol = i->getSymbol(); 588 int64_t Addend; 589 if (auto AddendOrErr = i->getAddend()) 590 Addend = *AddendOrErr; 591 else 592 return errorCodeToError(AddendOrErr.getError()); 593 594 ++i; 595 if (i == e) 596 break; 597 598 // Just check if following relocation is a R_PPC64_TOC 599 uint64_t TypeTOC = i->getType(); 600 if (TypeTOC != ELF::R_PPC64_TOC) 601 continue; 602 603 // Finally compares the Symbol value and the target symbol offset 604 // to check if this .opd entry refers to the symbol the relocation 605 // points to. 606 if (Rel.Addend != (int64_t)TargetSymbolOffset) 607 continue; 608 609 section_iterator TSI = Obj.section_end(); 610 if (auto TSIOrErr = TargetSymbol->getSection()) 611 TSI = *TSIOrErr; 612 else 613 return TSIOrErr.takeError(); 614 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 615 616 bool IsCode = TSI->isText(); 617 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 618 LocalSections)) 619 Rel.SectionID = *SectionIDOrErr; 620 else 621 return SectionIDOrErr.takeError(); 622 Rel.Addend = (intptr_t)Addend; 623 return Error::success(); 624 } 625 } 626 llvm_unreachable("Attempting to get address of ODP entry!"); 627 } 628 629 // Relocation masks following the #lo(value), #hi(value), #ha(value), 630 // #higher(value), #highera(value), #highest(value), and #highesta(value) 631 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 632 // document. 633 634 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 635 636 static inline uint16_t applyPPChi(uint64_t value) { 637 return (value >> 16) & 0xffff; 638 } 639 640 static inline uint16_t applyPPCha (uint64_t value) { 641 return ((value + 0x8000) >> 16) & 0xffff; 642 } 643 644 static inline uint16_t applyPPChigher(uint64_t value) { 645 return (value >> 32) & 0xffff; 646 } 647 648 static inline uint16_t applyPPChighera (uint64_t value) { 649 return ((value + 0x8000) >> 32) & 0xffff; 650 } 651 652 static inline uint16_t applyPPChighest(uint64_t value) { 653 return (value >> 48) & 0xffff; 654 } 655 656 static inline uint16_t applyPPChighesta (uint64_t value) { 657 return ((value + 0x8000) >> 48) & 0xffff; 658 } 659 660 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 661 uint64_t Offset, uint64_t Value, 662 uint32_t Type, int64_t Addend) { 663 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 664 switch (Type) { 665 default: 666 llvm_unreachable("Relocation type not implemented yet!"); 667 break; 668 case ELF::R_PPC_ADDR16_LO: 669 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 670 break; 671 case ELF::R_PPC_ADDR16_HI: 672 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 673 break; 674 case ELF::R_PPC_ADDR16_HA: 675 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 676 break; 677 } 678 } 679 680 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 681 uint64_t Offset, uint64_t Value, 682 uint32_t Type, int64_t Addend) { 683 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 684 switch (Type) { 685 default: 686 llvm_unreachable("Relocation type not implemented yet!"); 687 break; 688 case ELF::R_PPC64_ADDR16: 689 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 690 break; 691 case ELF::R_PPC64_ADDR16_DS: 692 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 693 break; 694 case ELF::R_PPC64_ADDR16_LO: 695 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 696 break; 697 case ELF::R_PPC64_ADDR16_LO_DS: 698 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 699 break; 700 case ELF::R_PPC64_ADDR16_HI: 701 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 702 break; 703 case ELF::R_PPC64_ADDR16_HA: 704 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 705 break; 706 case ELF::R_PPC64_ADDR16_HIGHER: 707 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 708 break; 709 case ELF::R_PPC64_ADDR16_HIGHERA: 710 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 711 break; 712 case ELF::R_PPC64_ADDR16_HIGHEST: 713 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 714 break; 715 case ELF::R_PPC64_ADDR16_HIGHESTA: 716 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 717 break; 718 case ELF::R_PPC64_ADDR14: { 719 assert(((Value + Addend) & 3) == 0); 720 // Preserve the AA/LK bits in the branch instruction 721 uint8_t aalk = *(LocalAddress + 3); 722 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 723 } break; 724 case ELF::R_PPC64_REL16_LO: { 725 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 726 uint64_t Delta = Value - FinalAddress + Addend; 727 writeInt16BE(LocalAddress, applyPPClo(Delta)); 728 } break; 729 case ELF::R_PPC64_REL16_HI: { 730 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 731 uint64_t Delta = Value - FinalAddress + Addend; 732 writeInt16BE(LocalAddress, applyPPChi(Delta)); 733 } break; 734 case ELF::R_PPC64_REL16_HA: { 735 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 736 uint64_t Delta = Value - FinalAddress + Addend; 737 writeInt16BE(LocalAddress, applyPPCha(Delta)); 738 } break; 739 case ELF::R_PPC64_ADDR32: { 740 int64_t Result = static_cast<int64_t>(Value + Addend); 741 if (SignExtend64<32>(Result) != Result) 742 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 743 writeInt32BE(LocalAddress, Result); 744 } break; 745 case ELF::R_PPC64_REL24: { 746 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 747 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 748 if (SignExtend64<26>(delta) != delta) 749 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 750 // Generates a 'bl <address>' instruction 751 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); 752 } break; 753 case ELF::R_PPC64_REL32: { 754 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 755 int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); 756 if (SignExtend64<32>(delta) != delta) 757 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 758 writeInt32BE(LocalAddress, delta); 759 } break; 760 case ELF::R_PPC64_REL64: { 761 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 762 uint64_t Delta = Value - FinalAddress + Addend; 763 writeInt64BE(LocalAddress, Delta); 764 } break; 765 case ELF::R_PPC64_ADDR64: 766 writeInt64BE(LocalAddress, Value + Addend); 767 break; 768 } 769 } 770 771 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 772 uint64_t Offset, uint64_t Value, 773 uint32_t Type, int64_t Addend) { 774 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 775 switch (Type) { 776 default: 777 llvm_unreachable("Relocation type not implemented yet!"); 778 break; 779 case ELF::R_390_PC16DBL: 780 case ELF::R_390_PLT16DBL: { 781 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 782 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 783 writeInt16BE(LocalAddress, Delta / 2); 784 break; 785 } 786 case ELF::R_390_PC32DBL: 787 case ELF::R_390_PLT32DBL: { 788 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 789 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 790 writeInt32BE(LocalAddress, Delta / 2); 791 break; 792 } 793 case ELF::R_390_PC16: { 794 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 795 assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); 796 writeInt16BE(LocalAddress, Delta); 797 break; 798 } 799 case ELF::R_390_PC32: { 800 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 801 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 802 writeInt32BE(LocalAddress, Delta); 803 break; 804 } 805 case ELF::R_390_PC64: { 806 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 807 writeInt64BE(LocalAddress, Delta); 808 break; 809 } 810 case ELF::R_390_8: 811 *LocalAddress = (uint8_t)(Value + Addend); 812 break; 813 case ELF::R_390_16: 814 writeInt16BE(LocalAddress, Value + Addend); 815 break; 816 case ELF::R_390_32: 817 writeInt32BE(LocalAddress, Value + Addend); 818 break; 819 case ELF::R_390_64: 820 writeInt64BE(LocalAddress, Value + Addend); 821 break; 822 } 823 } 824 825 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 826 uint64_t Offset, uint64_t Value, 827 uint32_t Type, int64_t Addend) { 828 bool isBE = Arch == Triple::bpfeb; 829 830 switch (Type) { 831 default: 832 llvm_unreachable("Relocation type not implemented yet!"); 833 break; 834 case ELF::R_BPF_NONE: 835 break; 836 case ELF::R_BPF_64_64: { 837 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 838 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 839 << format("%p\n", Section.getAddressWithOffset(Offset))); 840 break; 841 } 842 case ELF::R_BPF_64_32: { 843 Value += Addend; 844 assert(Value <= UINT32_MAX); 845 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 846 DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 847 << format("%p\n", Section.getAddressWithOffset(Offset))); 848 break; 849 } 850 } 851 } 852 853 // The target location for the relocation is described by RE.SectionID and 854 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 855 // SectionEntry has three members describing its location. 856 // SectionEntry::Address is the address at which the section has been loaded 857 // into memory in the current (host) process. SectionEntry::LoadAddress is the 858 // address that the section will have in the target process. 859 // SectionEntry::ObjAddress is the address of the bits for this section in the 860 // original emitted object image (also in the current address space). 861 // 862 // Relocations will be applied as if the section were loaded at 863 // SectionEntry::LoadAddress, but they will be applied at an address based 864 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 865 // Target memory contents if they are required for value calculations. 866 // 867 // The Value parameter here is the load address of the symbol for the 868 // relocation to be applied. For relocations which refer to symbols in the 869 // current object Value will be the LoadAddress of the section in which 870 // the symbol resides (RE.Addend provides additional information about the 871 // symbol location). For external symbols, Value will be the address of the 872 // symbol in the target address space. 873 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 874 uint64_t Value) { 875 const SectionEntry &Section = Sections[RE.SectionID]; 876 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 877 RE.SymOffset, RE.SectionID); 878 } 879 880 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 881 uint64_t Offset, uint64_t Value, 882 uint32_t Type, int64_t Addend, 883 uint64_t SymOffset, SID SectionID) { 884 switch (Arch) { 885 case Triple::x86_64: 886 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 887 break; 888 case Triple::x86: 889 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 890 (uint32_t)(Addend & 0xffffffffL)); 891 break; 892 case Triple::aarch64: 893 case Triple::aarch64_be: 894 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 895 break; 896 case Triple::arm: // Fall through. 897 case Triple::armeb: 898 case Triple::thumb: 899 case Triple::thumbeb: 900 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 901 (uint32_t)(Addend & 0xffffffffL)); 902 break; 903 case Triple::ppc: 904 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 905 break; 906 case Triple::ppc64: // Fall through. 907 case Triple::ppc64le: 908 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 909 break; 910 case Triple::systemz: 911 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 912 break; 913 case Triple::bpfel: 914 case Triple::bpfeb: 915 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 916 break; 917 default: 918 llvm_unreachable("Unsupported CPU type!"); 919 } 920 } 921 922 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 923 return (void *)(Sections[SectionID].getObjAddress() + Offset); 924 } 925 926 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 927 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 928 if (Value.SymbolName) 929 addRelocationForSymbol(RE, Value.SymbolName); 930 else 931 addRelocationForSection(RE, Value.SectionID); 932 } 933 934 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 935 bool IsLocal) const { 936 switch (RelType) { 937 case ELF::R_MICROMIPS_GOT16: 938 if (IsLocal) 939 return ELF::R_MICROMIPS_LO16; 940 break; 941 case ELF::R_MICROMIPS_HI16: 942 return ELF::R_MICROMIPS_LO16; 943 case ELF::R_MIPS_GOT16: 944 if (IsLocal) 945 return ELF::R_MIPS_LO16; 946 break; 947 case ELF::R_MIPS_HI16: 948 return ELF::R_MIPS_LO16; 949 case ELF::R_MIPS_PCHI16: 950 return ELF::R_MIPS_PCLO16; 951 default: 952 break; 953 } 954 return ELF::R_MIPS_NONE; 955 } 956 957 // Sometimes we don't need to create thunk for a branch. 958 // This typically happens when branch target is located 959 // in the same object file. In such case target is either 960 // a weak symbol or symbol in a different executable section. 961 // This function checks if branch target is located in the 962 // same object file and if distance between source and target 963 // fits R_AARCH64_CALL26 relocation. If both conditions are 964 // met, it emits direct jump to the target and returns true. 965 // Otherwise false is returned and thunk is created. 966 bool RuntimeDyldELF::resolveAArch64ShortBranch( 967 unsigned SectionID, relocation_iterator RelI, 968 const RelocationValueRef &Value) { 969 uint64_t Address; 970 if (Value.SymbolName) { 971 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 972 973 // Don't create direct branch for external symbols. 974 if (Loc == GlobalSymbolTable.end()) 975 return false; 976 977 const auto &SymInfo = Loc->second; 978 Address = 979 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 980 SymInfo.getOffset())); 981 } else { 982 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 983 } 984 uint64_t Offset = RelI->getOffset(); 985 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 986 987 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 988 // If distance between source and target is out of range then we should 989 // create thunk. 990 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 991 return false; 992 993 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 994 Value.Addend); 995 996 return true; 997 } 998 999 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 1000 const RelocationValueRef &Value, 1001 relocation_iterator RelI, 1002 StubMap &Stubs) { 1003 1004 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1005 SectionEntry &Section = Sections[SectionID]; 1006 1007 uint64_t Offset = RelI->getOffset(); 1008 unsigned RelType = RelI->getType(); 1009 // Look for an existing stub. 1010 StubMap::const_iterator i = Stubs.find(Value); 1011 if (i != Stubs.end()) { 1012 resolveRelocation(Section, Offset, 1013 (uint64_t)Section.getAddressWithOffset(i->second), 1014 RelType, 0); 1015 DEBUG(dbgs() << " Stub function found\n"); 1016 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1017 // Create a new stub function. 1018 DEBUG(dbgs() << " Create a new stub function\n"); 1019 Stubs[Value] = Section.getStubOffset(); 1020 uint8_t *StubTargetAddr = createStubFunction( 1021 Section.getAddressWithOffset(Section.getStubOffset())); 1022 1023 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1024 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1025 RelocationEntry REmovk_g2(SectionID, 1026 StubTargetAddr - Section.getAddress() + 4, 1027 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1028 RelocationEntry REmovk_g1(SectionID, 1029 StubTargetAddr - Section.getAddress() + 8, 1030 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1031 RelocationEntry REmovk_g0(SectionID, 1032 StubTargetAddr - Section.getAddress() + 12, 1033 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1034 1035 if (Value.SymbolName) { 1036 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1037 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1038 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1039 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1040 } else { 1041 addRelocationForSection(REmovz_g3, Value.SectionID); 1042 addRelocationForSection(REmovk_g2, Value.SectionID); 1043 addRelocationForSection(REmovk_g1, Value.SectionID); 1044 addRelocationForSection(REmovk_g0, Value.SectionID); 1045 } 1046 resolveRelocation(Section, Offset, 1047 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1048 Section.getStubOffset())), 1049 RelType, 0); 1050 Section.advanceStubOffset(getMaxStubSize()); 1051 } 1052 } 1053 1054 Expected<relocation_iterator> 1055 RuntimeDyldELF::processRelocationRef( 1056 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1057 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1058 const auto &Obj = cast<ELFObjectFileBase>(O); 1059 uint64_t RelType = RelI->getType(); 1060 ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend(); 1061 int64_t Addend = AddendOrErr ? *AddendOrErr : 0; 1062 elf_symbol_iterator Symbol = RelI->getSymbol(); 1063 1064 // Obtain the symbol name which is referenced in the relocation 1065 StringRef TargetName; 1066 if (Symbol != Obj.symbol_end()) { 1067 if (auto TargetNameOrErr = Symbol->getName()) 1068 TargetName = *TargetNameOrErr; 1069 else 1070 return TargetNameOrErr.takeError(); 1071 } 1072 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1073 << " TargetName: " << TargetName << "\n"); 1074 RelocationValueRef Value; 1075 // First search for the symbol in the local symbol table 1076 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1077 1078 // Search for the symbol in the global symbol table 1079 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1080 if (Symbol != Obj.symbol_end()) { 1081 gsi = GlobalSymbolTable.find(TargetName.data()); 1082 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1083 if (!SymTypeOrErr) { 1084 std::string Buf; 1085 raw_string_ostream OS(Buf); 1086 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, ""); 1087 OS.flush(); 1088 report_fatal_error(Buf); 1089 } 1090 SymType = *SymTypeOrErr; 1091 } 1092 if (gsi != GlobalSymbolTable.end()) { 1093 const auto &SymInfo = gsi->second; 1094 Value.SectionID = SymInfo.getSectionID(); 1095 Value.Offset = SymInfo.getOffset(); 1096 Value.Addend = SymInfo.getOffset() + Addend; 1097 } else { 1098 switch (SymType) { 1099 case SymbolRef::ST_Debug: { 1100 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1101 // and can be changed by another developers. Maybe best way is add 1102 // a new symbol type ST_Section to SymbolRef and use it. 1103 auto SectionOrErr = Symbol->getSection(); 1104 if (!SectionOrErr) { 1105 std::string Buf; 1106 raw_string_ostream OS(Buf); 1107 logAllUnhandledErrors(SectionOrErr.takeError(), OS, ""); 1108 OS.flush(); 1109 report_fatal_error(Buf); 1110 } 1111 section_iterator si = *SectionOrErr; 1112 if (si == Obj.section_end()) 1113 llvm_unreachable("Symbol section not found, bad object file format!"); 1114 DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1115 bool isCode = si->isText(); 1116 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1117 ObjSectionToID)) 1118 Value.SectionID = *SectionIDOrErr; 1119 else 1120 return SectionIDOrErr.takeError(); 1121 Value.Addend = Addend; 1122 break; 1123 } 1124 case SymbolRef::ST_Data: 1125 case SymbolRef::ST_Function: 1126 case SymbolRef::ST_Unknown: { 1127 Value.SymbolName = TargetName.data(); 1128 Value.Addend = Addend; 1129 1130 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1131 // will manifest here as a NULL symbol name. 1132 // We can set this as a valid (but empty) symbol name, and rely 1133 // on addRelocationForSymbol to handle this. 1134 if (!Value.SymbolName) 1135 Value.SymbolName = ""; 1136 break; 1137 } 1138 default: 1139 llvm_unreachable("Unresolved symbol type!"); 1140 break; 1141 } 1142 } 1143 1144 uint64_t Offset = RelI->getOffset(); 1145 1146 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1147 << "\n"); 1148 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1149 if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { 1150 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1151 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1152 // Craete new GOT entry or find existing one. If GOT entry is 1153 // to be created, then we also emit ABS64 relocation for it. 1154 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1155 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1156 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1157 1158 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1159 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1160 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1161 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1162 } else { 1163 processSimpleRelocation(SectionID, Offset, RelType, Value); 1164 } 1165 } else if (Arch == Triple::arm) { 1166 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1167 RelType == ELF::R_ARM_JUMP24) { 1168 // This is an ARM branch relocation, need to use a stub function. 1169 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1170 SectionEntry &Section = Sections[SectionID]; 1171 1172 // Look for an existing stub. 1173 StubMap::const_iterator i = Stubs.find(Value); 1174 if (i != Stubs.end()) { 1175 resolveRelocation( 1176 Section, Offset, 1177 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1178 RelType, 0); 1179 DEBUG(dbgs() << " Stub function found\n"); 1180 } else { 1181 // Create a new stub function. 1182 DEBUG(dbgs() << " Create a new stub function\n"); 1183 Stubs[Value] = Section.getStubOffset(); 1184 uint8_t *StubTargetAddr = createStubFunction( 1185 Section.getAddressWithOffset(Section.getStubOffset())); 1186 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1187 ELF::R_ARM_ABS32, Value.Addend); 1188 if (Value.SymbolName) 1189 addRelocationForSymbol(RE, Value.SymbolName); 1190 else 1191 addRelocationForSection(RE, Value.SectionID); 1192 1193 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1194 Section.getAddressWithOffset( 1195 Section.getStubOffset())), 1196 RelType, 0); 1197 Section.advanceStubOffset(getMaxStubSize()); 1198 } 1199 } else { 1200 uint32_t *Placeholder = 1201 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1202 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1203 RelType == ELF::R_ARM_ABS32) { 1204 Value.Addend += *Placeholder; 1205 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1206 // See ELF for ARM documentation 1207 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1208 } 1209 processSimpleRelocation(SectionID, Offset, RelType, Value); 1210 } 1211 } else if (IsMipsO32ABI) { 1212 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1213 computePlaceholderAddress(SectionID, Offset)); 1214 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1215 if (RelType == ELF::R_MIPS_26) { 1216 // This is an Mips branch relocation, need to use a stub function. 1217 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1218 SectionEntry &Section = Sections[SectionID]; 1219 1220 // Extract the addend from the instruction. 1221 // We shift up by two since the Value will be down shifted again 1222 // when applying the relocation. 1223 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1224 1225 Value.Addend += Addend; 1226 1227 // Look up for existing stub. 1228 StubMap::const_iterator i = Stubs.find(Value); 1229 if (i != Stubs.end()) { 1230 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1231 addRelocationForSection(RE, SectionID); 1232 DEBUG(dbgs() << " Stub function found\n"); 1233 } else { 1234 // Create a new stub function. 1235 DEBUG(dbgs() << " Create a new stub function\n"); 1236 Stubs[Value] = Section.getStubOffset(); 1237 1238 unsigned AbiVariant; 1239 O.getPlatformFlags(AbiVariant); 1240 1241 uint8_t *StubTargetAddr = createStubFunction( 1242 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1243 1244 // Creating Hi and Lo relocations for the filled stub instructions. 1245 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1246 ELF::R_MIPS_HI16, Value.Addend); 1247 RelocationEntry RELo(SectionID, 1248 StubTargetAddr - Section.getAddress() + 4, 1249 ELF::R_MIPS_LO16, Value.Addend); 1250 1251 if (Value.SymbolName) { 1252 addRelocationForSymbol(REHi, Value.SymbolName); 1253 addRelocationForSymbol(RELo, Value.SymbolName); 1254 } 1255 else { 1256 addRelocationForSection(REHi, Value.SectionID); 1257 addRelocationForSection(RELo, Value.SectionID); 1258 } 1259 1260 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1261 addRelocationForSection(RE, SectionID); 1262 Section.advanceStubOffset(getMaxStubSize()); 1263 } 1264 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1265 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1266 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1267 PendingRelocs.push_back(std::make_pair(Value, RE)); 1268 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1269 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1270 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1271 const RelocationValueRef &MatchingValue = I->first; 1272 RelocationEntry &Reloc = I->second; 1273 if (MatchingValue == Value && 1274 RelType == getMatchingLoRelocation(Reloc.RelType) && 1275 SectionID == Reloc.SectionID) { 1276 Reloc.Addend += Addend; 1277 if (Value.SymbolName) 1278 addRelocationForSymbol(Reloc, Value.SymbolName); 1279 else 1280 addRelocationForSection(Reloc, Value.SectionID); 1281 I = PendingRelocs.erase(I); 1282 } else 1283 ++I; 1284 } 1285 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1286 if (Value.SymbolName) 1287 addRelocationForSymbol(RE, Value.SymbolName); 1288 else 1289 addRelocationForSection(RE, Value.SectionID); 1290 } else { 1291 if (RelType == ELF::R_MIPS_32) 1292 Value.Addend += Opcode; 1293 else if (RelType == ELF::R_MIPS_PC16) 1294 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1295 else if (RelType == ELF::R_MIPS_PC19_S2) 1296 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1297 else if (RelType == ELF::R_MIPS_PC21_S2) 1298 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1299 else if (RelType == ELF::R_MIPS_PC26_S2) 1300 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1301 processSimpleRelocation(SectionID, Offset, RelType, Value); 1302 } 1303 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1304 uint32_t r_type = RelType & 0xff; 1305 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1306 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1307 || r_type == ELF::R_MIPS_GOT_DISP) { 1308 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1309 if (i != GOTSymbolOffsets.end()) 1310 RE.SymOffset = i->second; 1311 else { 1312 RE.SymOffset = allocateGOTEntries(1); 1313 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1314 } 1315 } 1316 if (Value.SymbolName) 1317 addRelocationForSymbol(RE, Value.SymbolName); 1318 else 1319 addRelocationForSection(RE, Value.SectionID); 1320 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1321 if (RelType == ELF::R_PPC64_REL24) { 1322 // Determine ABI variant in use for this object. 1323 unsigned AbiVariant; 1324 Obj.getPlatformFlags(AbiVariant); 1325 AbiVariant &= ELF::EF_PPC64_ABI; 1326 // A PPC branch relocation will need a stub function if the target is 1327 // an external symbol (either Value.SymbolName is set, or SymType is 1328 // Symbol::ST_Unknown) or if the target address is not within the 1329 // signed 24-bits branch address. 1330 SectionEntry &Section = Sections[SectionID]; 1331 uint8_t *Target = Section.getAddressWithOffset(Offset); 1332 bool RangeOverflow = false; 1333 if (!Value.SymbolName && SymType != SymbolRef::ST_Unknown) { 1334 if (AbiVariant != 2) { 1335 // In the ELFv1 ABI, a function call may point to the .opd entry, 1336 // so the final symbol value is calculated based on the relocation 1337 // values in the .opd section. 1338 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1339 return std::move(Err); 1340 } else { 1341 // In the ELFv2 ABI, a function symbol may provide a local entry 1342 // point, which must be used for direct calls. 1343 uint8_t SymOther = Symbol->getOther(); 1344 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1345 } 1346 uint8_t *RelocTarget = 1347 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1348 int64_t delta = static_cast<int64_t>(Target - RelocTarget); 1349 // If it is within 26-bits branch range, just set the branch target 1350 if (SignExtend64<26>(delta) == delta) { 1351 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1352 addRelocationForSection(RE, Value.SectionID); 1353 } else { 1354 RangeOverflow = true; 1355 } 1356 } 1357 if (Value.SymbolName || SymType == SymbolRef::ST_Unknown || 1358 RangeOverflow) { 1359 // It is an external symbol (either Value.SymbolName is set, or 1360 // SymType is SymbolRef::ST_Unknown) or out of range. 1361 StubMap::const_iterator i = Stubs.find(Value); 1362 if (i != Stubs.end()) { 1363 // Symbol function stub already created, just relocate to it 1364 resolveRelocation(Section, Offset, 1365 reinterpret_cast<uint64_t>( 1366 Section.getAddressWithOffset(i->second)), 1367 RelType, 0); 1368 DEBUG(dbgs() << " Stub function found\n"); 1369 } else { 1370 // Create a new stub function. 1371 DEBUG(dbgs() << " Create a new stub function\n"); 1372 Stubs[Value] = Section.getStubOffset(); 1373 uint8_t *StubTargetAddr = createStubFunction( 1374 Section.getAddressWithOffset(Section.getStubOffset()), 1375 AbiVariant); 1376 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1377 ELF::R_PPC64_ADDR64, Value.Addend); 1378 1379 // Generates the 64-bits address loads as exemplified in section 1380 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1381 // apply to the low part of the instructions, so we have to update 1382 // the offset according to the target endianness. 1383 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1384 if (!IsTargetLittleEndian) 1385 StubRelocOffset += 2; 1386 1387 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1388 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1389 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1390 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1391 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1392 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1393 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1394 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1395 1396 if (Value.SymbolName) { 1397 addRelocationForSymbol(REhst, Value.SymbolName); 1398 addRelocationForSymbol(REhr, Value.SymbolName); 1399 addRelocationForSymbol(REh, Value.SymbolName); 1400 addRelocationForSymbol(REl, Value.SymbolName); 1401 } else { 1402 addRelocationForSection(REhst, Value.SectionID); 1403 addRelocationForSection(REhr, Value.SectionID); 1404 addRelocationForSection(REh, Value.SectionID); 1405 addRelocationForSection(REl, Value.SectionID); 1406 } 1407 1408 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1409 Section.getAddressWithOffset( 1410 Section.getStubOffset())), 1411 RelType, 0); 1412 Section.advanceStubOffset(getMaxStubSize()); 1413 } 1414 if (Value.SymbolName || SymType == SymbolRef::ST_Unknown) { 1415 // Restore the TOC for external calls 1416 if (AbiVariant == 2) 1417 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1) 1418 else 1419 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1420 } 1421 } 1422 } else if (RelType == ELF::R_PPC64_TOC16 || 1423 RelType == ELF::R_PPC64_TOC16_DS || 1424 RelType == ELF::R_PPC64_TOC16_LO || 1425 RelType == ELF::R_PPC64_TOC16_LO_DS || 1426 RelType == ELF::R_PPC64_TOC16_HI || 1427 RelType == ELF::R_PPC64_TOC16_HA) { 1428 // These relocations are supposed to subtract the TOC address from 1429 // the final value. This does not fit cleanly into the RuntimeDyld 1430 // scheme, since there may be *two* sections involved in determining 1431 // the relocation value (the section of the symbol referred to by the 1432 // relocation, and the TOC section associated with the current module). 1433 // 1434 // Fortunately, these relocations are currently only ever generated 1435 // referring to symbols that themselves reside in the TOC, which means 1436 // that the two sections are actually the same. Thus they cancel out 1437 // and we can immediately resolve the relocation right now. 1438 switch (RelType) { 1439 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1440 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1441 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1442 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1443 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1444 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1445 default: llvm_unreachable("Wrong relocation type."); 1446 } 1447 1448 RelocationValueRef TOCValue; 1449 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1450 return std::move(Err); 1451 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1452 llvm_unreachable("Unsupported TOC relocation."); 1453 Value.Addend -= TOCValue.Addend; 1454 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1455 } else { 1456 // There are two ways to refer to the TOC address directly: either 1457 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1458 // ignored), or via any relocation that refers to the magic ".TOC." 1459 // symbols (in which case the addend is respected). 1460 if (RelType == ELF::R_PPC64_TOC) { 1461 RelType = ELF::R_PPC64_ADDR64; 1462 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1463 return std::move(Err); 1464 } else if (TargetName == ".TOC.") { 1465 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1466 return std::move(Err); 1467 Value.Addend += Addend; 1468 } 1469 1470 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1471 1472 if (Value.SymbolName) 1473 addRelocationForSymbol(RE, Value.SymbolName); 1474 else 1475 addRelocationForSection(RE, Value.SectionID); 1476 } 1477 } else if (Arch == Triple::systemz && 1478 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1479 // Create function stubs for both PLT and GOT references, regardless of 1480 // whether the GOT reference is to data or code. The stub contains the 1481 // full address of the symbol, as needed by GOT references, and the 1482 // executable part only adds an overhead of 8 bytes. 1483 // 1484 // We could try to conserve space by allocating the code and data 1485 // parts of the stub separately. However, as things stand, we allocate 1486 // a stub for every relocation, so using a GOT in JIT code should be 1487 // no less space efficient than using an explicit constant pool. 1488 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1489 SectionEntry &Section = Sections[SectionID]; 1490 1491 // Look for an existing stub. 1492 StubMap::const_iterator i = Stubs.find(Value); 1493 uintptr_t StubAddress; 1494 if (i != Stubs.end()) { 1495 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1496 DEBUG(dbgs() << " Stub function found\n"); 1497 } else { 1498 // Create a new stub function. 1499 DEBUG(dbgs() << " Create a new stub function\n"); 1500 1501 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1502 uintptr_t StubAlignment = getStubAlignment(); 1503 StubAddress = 1504 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1505 -StubAlignment; 1506 unsigned StubOffset = StubAddress - BaseAddress; 1507 1508 Stubs[Value] = StubOffset; 1509 createStubFunction((uint8_t *)StubAddress); 1510 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1511 Value.Offset); 1512 if (Value.SymbolName) 1513 addRelocationForSymbol(RE, Value.SymbolName); 1514 else 1515 addRelocationForSection(RE, Value.SectionID); 1516 Section.advanceStubOffset(getMaxStubSize()); 1517 } 1518 1519 if (RelType == ELF::R_390_GOTENT) 1520 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1521 Addend); 1522 else 1523 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1524 } else if (Arch == Triple::x86_64) { 1525 if (RelType == ELF::R_X86_64_PLT32) { 1526 // The way the PLT relocations normally work is that the linker allocates 1527 // the 1528 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1529 // entry will then jump to an address provided by the GOT. On first call, 1530 // the 1531 // GOT address will point back into PLT code that resolves the symbol. After 1532 // the first call, the GOT entry points to the actual function. 1533 // 1534 // For local functions we're ignoring all of that here and just replacing 1535 // the PLT32 relocation type with PC32, which will translate the relocation 1536 // into a PC-relative call directly to the function. For external symbols we 1537 // can't be sure the function will be within 2^32 bytes of the call site, so 1538 // we need to create a stub, which calls into the GOT. This case is 1539 // equivalent to the usual PLT implementation except that we use the stub 1540 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1541 // rather than allocating a PLT section. 1542 if (Value.SymbolName) { 1543 // This is a call to an external function. 1544 // Look for an existing stub. 1545 SectionEntry &Section = Sections[SectionID]; 1546 StubMap::const_iterator i = Stubs.find(Value); 1547 uintptr_t StubAddress; 1548 if (i != Stubs.end()) { 1549 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1550 DEBUG(dbgs() << " Stub function found\n"); 1551 } else { 1552 // Create a new stub function (equivalent to a PLT entry). 1553 DEBUG(dbgs() << " Create a new stub function\n"); 1554 1555 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1556 uintptr_t StubAlignment = getStubAlignment(); 1557 StubAddress = 1558 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1559 -StubAlignment; 1560 unsigned StubOffset = StubAddress - BaseAddress; 1561 Stubs[Value] = StubOffset; 1562 createStubFunction((uint8_t *)StubAddress); 1563 1564 // Bump our stub offset counter 1565 Section.advanceStubOffset(getMaxStubSize()); 1566 1567 // Allocate a GOT Entry 1568 uint64_t GOTOffset = allocateGOTEntries(1); 1569 1570 // The load of the GOT address has an addend of -4 1571 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1572 ELF::R_X86_64_PC32); 1573 1574 // Fill in the value of the symbol we're targeting into the GOT 1575 addRelocationForSymbol( 1576 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1577 Value.SymbolName); 1578 } 1579 1580 // Make the target call a call into the stub table. 1581 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1582 Addend); 1583 } else { 1584 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1585 Value.Offset); 1586 addRelocationForSection(RE, Value.SectionID); 1587 } 1588 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1589 RelType == ELF::R_X86_64_GOTPCRELX || 1590 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1591 uint64_t GOTOffset = allocateGOTEntries(1); 1592 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1593 ELF::R_X86_64_PC32); 1594 1595 // Fill in the value of the symbol we're targeting into the GOT 1596 RelocationEntry RE = 1597 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1598 if (Value.SymbolName) 1599 addRelocationForSymbol(RE, Value.SymbolName); 1600 else 1601 addRelocationForSection(RE, Value.SectionID); 1602 } else if (RelType == ELF::R_X86_64_PC32) { 1603 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1604 processSimpleRelocation(SectionID, Offset, RelType, Value); 1605 } else if (RelType == ELF::R_X86_64_PC64) { 1606 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1607 processSimpleRelocation(SectionID, Offset, RelType, Value); 1608 } else { 1609 processSimpleRelocation(SectionID, Offset, RelType, Value); 1610 } 1611 } else { 1612 if (Arch == Triple::x86) { 1613 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1614 } 1615 processSimpleRelocation(SectionID, Offset, RelType, Value); 1616 } 1617 return ++RelI; 1618 } 1619 1620 size_t RuntimeDyldELF::getGOTEntrySize() { 1621 // We don't use the GOT in all of these cases, but it's essentially free 1622 // to put them all here. 1623 size_t Result = 0; 1624 switch (Arch) { 1625 case Triple::x86_64: 1626 case Triple::aarch64: 1627 case Triple::aarch64_be: 1628 case Triple::ppc64: 1629 case Triple::ppc64le: 1630 case Triple::systemz: 1631 Result = sizeof(uint64_t); 1632 break; 1633 case Triple::x86: 1634 case Triple::arm: 1635 case Triple::thumb: 1636 Result = sizeof(uint32_t); 1637 break; 1638 case Triple::mips: 1639 case Triple::mipsel: 1640 case Triple::mips64: 1641 case Triple::mips64el: 1642 if (IsMipsO32ABI || IsMipsN32ABI) 1643 Result = sizeof(uint32_t); 1644 else if (IsMipsN64ABI) 1645 Result = sizeof(uint64_t); 1646 else 1647 llvm_unreachable("Mips ABI not handled"); 1648 break; 1649 default: 1650 llvm_unreachable("Unsupported CPU type!"); 1651 } 1652 return Result; 1653 } 1654 1655 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 1656 if (GOTSectionID == 0) { 1657 GOTSectionID = Sections.size(); 1658 // Reserve a section id. We'll allocate the section later 1659 // once we know the total size 1660 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1661 } 1662 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1663 CurrentGOTIndex += no; 1664 return StartOffset; 1665 } 1666 1667 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 1668 unsigned GOTRelType) { 1669 auto E = GOTOffsetMap.insert({Value, 0}); 1670 if (E.second) { 1671 uint64_t GOTOffset = allocateGOTEntries(1); 1672 1673 // Create relocation for newly created GOT entry 1674 RelocationEntry RE = 1675 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 1676 if (Value.SymbolName) 1677 addRelocationForSymbol(RE, Value.SymbolName); 1678 else 1679 addRelocationForSection(RE, Value.SectionID); 1680 1681 E.first->second = GOTOffset; 1682 } 1683 1684 return E.first->second; 1685 } 1686 1687 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 1688 uint64_t Offset, 1689 uint64_t GOTOffset, 1690 uint32_t Type) { 1691 // Fill in the relative address of the GOT Entry into the stub 1692 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 1693 addRelocationForSection(GOTRE, GOTSectionID); 1694 } 1695 1696 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 1697 uint64_t SymbolOffset, 1698 uint32_t Type) { 1699 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1700 } 1701 1702 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1703 ObjSectionToIDMap &SectionMap) { 1704 if (IsMipsO32ABI) 1705 if (!PendingRelocs.empty()) 1706 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1707 1708 // If necessary, allocate the global offset table 1709 if (GOTSectionID != 0) { 1710 // Allocate memory for the section 1711 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1712 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1713 GOTSectionID, ".got", false); 1714 if (!Addr) 1715 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1716 1717 Sections[GOTSectionID] = 1718 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1719 1720 if (Checker) 1721 Checker->registerSection(Obj.getFileName(), GOTSectionID); 1722 1723 // For now, initialize all GOT entries to zero. We'll fill them in as 1724 // needed when GOT-based relocations are applied. 1725 memset(Addr, 0, TotalSize); 1726 if (IsMipsN32ABI || IsMipsN64ABI) { 1727 // To correctly resolve Mips GOT relocations, we need a mapping from 1728 // object's sections to GOTs. 1729 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1730 SI != SE; ++SI) { 1731 if (SI->relocation_begin() != SI->relocation_end()) { 1732 section_iterator RelocatedSection = SI->getRelocatedSection(); 1733 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1734 assert (i != SectionMap.end()); 1735 SectionToGOTMap[i->second] = GOTSectionID; 1736 } 1737 } 1738 GOTSymbolOffsets.clear(); 1739 } 1740 } 1741 1742 // Look for and record the EH frame section. 1743 ObjSectionToIDMap::iterator i, e; 1744 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1745 const SectionRef &Section = i->first; 1746 StringRef Name; 1747 Section.getName(Name); 1748 if (Name == ".eh_frame") { 1749 UnregisteredEHFrameSections.push_back(i->second); 1750 break; 1751 } 1752 } 1753 1754 GOTSectionID = 0; 1755 CurrentGOTIndex = 0; 1756 1757 return Error::success(); 1758 } 1759 1760 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1761 return Obj.isELF(); 1762 } 1763 1764 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 1765 unsigned RelTy = R.getType(); 1766 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 1767 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 1768 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 1769 1770 if (Arch == Triple::x86_64) 1771 return RelTy == ELF::R_X86_64_GOTPCREL || 1772 RelTy == ELF::R_X86_64_GOTPCRELX || 1773 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 1774 return false; 1775 } 1776 1777 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1778 if (Arch != Triple::x86_64) 1779 return true; // Conservative answer 1780 1781 switch (R.getType()) { 1782 default: 1783 return true; // Conservative answer 1784 1785 1786 case ELF::R_X86_64_GOTPCREL: 1787 case ELF::R_X86_64_GOTPCRELX: 1788 case ELF::R_X86_64_REX_GOTPCRELX: 1789 case ELF::R_X86_64_PC32: 1790 case ELF::R_X86_64_PC64: 1791 case ELF::R_X86_64_64: 1792 // We know that these reloation types won't need a stub function. This list 1793 // can be extended as needed. 1794 return false; 1795 } 1796 } 1797 1798 } // namespace llvm 1799