1 //===-- RuntimeDyldELF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Implementation of ELF support for the MC-JIT runtime dynamic linker. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "RuntimeDyldELF.h" 15 #include "RuntimeDyldCheckerImpl.h" 16 #include "Targets/RuntimeDyldELFMips.h" 17 #include "llvm/ADT/IntervalMap.h" 18 #include "llvm/ADT/STLExtras.h" 19 #include "llvm/ADT/StringRef.h" 20 #include "llvm/ADT/Triple.h" 21 #include "llvm/MC/MCStreamer.h" 22 #include "llvm/Object/ELFObjectFile.h" 23 #include "llvm/Object/ObjectFile.h" 24 #include "llvm/Support/ELF.h" 25 #include "llvm/Support/Endian.h" 26 #include "llvm/Support/MemoryBuffer.h" 27 #include "llvm/Support/TargetRegistry.h" 28 29 using namespace llvm; 30 using namespace llvm::object; 31 using namespace llvm::support::endian; 32 33 #define DEBUG_TYPE "dyld" 34 35 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); } 36 37 static void or32AArch64Imm(void *L, uint64_t Imm) { 38 or32le(L, (Imm & 0xFFF) << 10); 39 } 40 41 template <class T> static void write(bool isBE, void *P, T V) { 42 isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V); 43 } 44 45 static void write32AArch64Addr(void *L, uint64_t Imm) { 46 uint32_t ImmLo = (Imm & 0x3) << 29; 47 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 48 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 49 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 50 } 51 52 // Return the bits [Start, End] from Val shifted Start bits. 53 // For instance, getBits(0xF0, 4, 8) returns 0xF. 54 static uint64_t getBits(uint64_t Val, int Start, int End) { 55 uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1; 56 return (Val >> Start) & Mask; 57 } 58 59 namespace { 60 61 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> { 62 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) 63 64 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr; 65 typedef Elf_Sym_Impl<ELFT> Elf_Sym; 66 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel; 67 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela; 68 69 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; 70 71 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; 72 73 public: 74 DyldELFObject(MemoryBufferRef Wrapper, std::error_code &ec); 75 76 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 77 78 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); 79 80 // Methods for type inquiry through isa, cast and dyn_cast 81 static inline bool classof(const Binary *v) { 82 return (isa<ELFObjectFile<ELFT>>(v) && 83 classof(cast<ELFObjectFile<ELFT>>(v))); 84 } 85 static inline bool classof(const ELFObjectFile<ELFT> *v) { 86 return v->isDyldType(); 87 } 88 }; 89 90 91 92 // The MemoryBuffer passed into this constructor is just a wrapper around the 93 // actual memory. Ultimately, the Binary parent class will take ownership of 94 // this MemoryBuffer object but not the underlying memory. 95 template <class ELFT> 96 DyldELFObject<ELFT>::DyldELFObject(MemoryBufferRef Wrapper, std::error_code &EC) 97 : ELFObjectFile<ELFT>(Wrapper, EC) { 98 this->isDyldELFObject = true; 99 } 100 101 template <class ELFT> 102 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 103 uint64_t Addr) { 104 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 105 Elf_Shdr *shdr = 106 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 107 108 // This assumes the address passed in matches the target address bitness 109 // The template-based type cast handles everything else. 110 shdr->sh_addr = static_cast<addr_type>(Addr); 111 } 112 113 template <class ELFT> 114 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 115 uint64_t Addr) { 116 117 Elf_Sym *sym = const_cast<Elf_Sym *>( 118 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 119 120 // This assumes the address passed in matches the target address bitness 121 // The template-based type cast handles everything else. 122 sym->st_value = static_cast<addr_type>(Addr); 123 } 124 125 class LoadedELFObjectInfo final 126 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedELFObjectInfo> { 127 public: 128 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap) 129 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {} 130 131 OwningBinary<ObjectFile> 132 getObjectForDebug(const ObjectFile &Obj) const override; 133 }; 134 135 template <typename ELFT> 136 std::unique_ptr<DyldELFObject<ELFT>> 137 createRTDyldELFObject(MemoryBufferRef Buffer, 138 const ObjectFile &SourceObject, 139 const LoadedELFObjectInfo &L, 140 std::error_code &ec) { 141 typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr; 142 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; 143 144 std::unique_ptr<DyldELFObject<ELFT>> Obj = 145 llvm::make_unique<DyldELFObject<ELFT>>(Buffer, ec); 146 147 // Iterate over all sections in the object. 148 auto SI = SourceObject.section_begin(); 149 for (const auto &Sec : Obj->sections()) { 150 StringRef SectionName; 151 Sec.getName(SectionName); 152 if (SectionName != "") { 153 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 154 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 155 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 156 157 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { 158 // This assumes that the address passed in matches the target address 159 // bitness. The template-based type cast handles everything else. 160 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 161 } 162 } 163 ++SI; 164 } 165 166 return Obj; 167 } 168 169 OwningBinary<ObjectFile> createELFDebugObject(const ObjectFile &Obj, 170 const LoadedELFObjectInfo &L) { 171 assert(Obj.isELF() && "Not an ELF object file."); 172 173 std::unique_ptr<MemoryBuffer> Buffer = 174 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 175 176 std::error_code ec; 177 178 std::unique_ptr<ObjectFile> DebugObj; 179 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) { 180 typedef ELFType<support::little, false> ELF32LE; 181 DebugObj = createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L, 182 ec); 183 } else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) { 184 typedef ELFType<support::big, false> ELF32BE; 185 DebugObj = createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L, 186 ec); 187 } else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) { 188 typedef ELFType<support::big, true> ELF64BE; 189 DebugObj = createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L, 190 ec); 191 } else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) { 192 typedef ELFType<support::little, true> ELF64LE; 193 DebugObj = createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L, 194 ec); 195 } else 196 llvm_unreachable("Unexpected ELF format"); 197 198 assert(!ec && "Could not construct copy ELF object file"); 199 200 return OwningBinary<ObjectFile>(std::move(DebugObj), std::move(Buffer)); 201 } 202 203 OwningBinary<ObjectFile> 204 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 205 return createELFDebugObject(Obj, *this); 206 } 207 208 } // anonymous namespace 209 210 namespace llvm { 211 212 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 213 JITSymbolResolver &Resolver) 214 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 215 RuntimeDyldELF::~RuntimeDyldELF() {} 216 217 void RuntimeDyldELF::registerEHFrames() { 218 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { 219 SID EHFrameSID = UnregisteredEHFrameSections[i]; 220 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 221 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 222 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 223 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 224 RegisteredEHFrameSections.push_back(EHFrameSID); 225 } 226 UnregisteredEHFrameSections.clear(); 227 } 228 229 void RuntimeDyldELF::deregisterEHFrames() { 230 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) { 231 SID EHFrameSID = RegisteredEHFrameSections[i]; 232 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); 233 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); 234 size_t EHFrameSize = Sections[EHFrameSID].getSize(); 235 MemMgr.deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 236 } 237 RegisteredEHFrameSections.clear(); 238 } 239 240 std::unique_ptr<RuntimeDyldELF> 241 llvm::RuntimeDyldELF::create(Triple::ArchType Arch, 242 RuntimeDyld::MemoryManager &MemMgr, 243 JITSymbolResolver &Resolver) { 244 switch (Arch) { 245 default: 246 return make_unique<RuntimeDyldELF>(MemMgr, Resolver); 247 case Triple::mips: 248 case Triple::mipsel: 249 case Triple::mips64: 250 case Triple::mips64el: 251 return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); 252 } 253 } 254 255 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 256 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 257 if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) 258 return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); 259 else { 260 HasError = true; 261 raw_string_ostream ErrStream(ErrorStr); 262 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, ""); 263 return nullptr; 264 } 265 } 266 267 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 268 uint64_t Offset, uint64_t Value, 269 uint32_t Type, int64_t Addend, 270 uint64_t SymOffset) { 271 switch (Type) { 272 default: 273 llvm_unreachable("Relocation type not implemented yet!"); 274 break; 275 case ELF::R_X86_64_NONE: 276 break; 277 case ELF::R_X86_64_64: { 278 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 279 Value + Addend; 280 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 281 << format("%p\n", Section.getAddressWithOffset(Offset))); 282 break; 283 } 284 case ELF::R_X86_64_32: 285 case ELF::R_X86_64_32S: { 286 Value += Addend; 287 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 288 (Type == ELF::R_X86_64_32S && 289 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 290 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 291 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 292 TruncatedAddr; 293 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 294 << format("%p\n", Section.getAddressWithOffset(Offset))); 295 break; 296 } 297 case ELF::R_X86_64_PC8: { 298 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 299 int64_t RealOffset = Value + Addend - FinalAddress; 300 assert(isInt<8>(RealOffset)); 301 int8_t TruncOffset = (RealOffset & 0xFF); 302 Section.getAddress()[Offset] = TruncOffset; 303 break; 304 } 305 case ELF::R_X86_64_PC32: { 306 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 307 int64_t RealOffset = Value + Addend - FinalAddress; 308 assert(isInt<32>(RealOffset)); 309 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 310 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 311 TruncOffset; 312 break; 313 } 314 case ELF::R_X86_64_PC64: { 315 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 316 int64_t RealOffset = Value + Addend - FinalAddress; 317 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = 318 RealOffset; 319 break; 320 } 321 } 322 } 323 324 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 325 uint64_t Offset, uint32_t Value, 326 uint32_t Type, int32_t Addend) { 327 switch (Type) { 328 case ELF::R_386_32: { 329 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 330 Value + Addend; 331 break; 332 } 333 case ELF::R_386_PC32: { 334 uint32_t FinalAddress = 335 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 336 uint32_t RealOffset = Value + Addend - FinalAddress; 337 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = 338 RealOffset; 339 break; 340 } 341 default: 342 // There are other relocation types, but it appears these are the 343 // only ones currently used by the LLVM ELF object writer 344 llvm_unreachable("Relocation type not implemented yet!"); 345 break; 346 } 347 } 348 349 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 350 uint64_t Offset, uint64_t Value, 351 uint32_t Type, int64_t Addend) { 352 uint32_t *TargetPtr = 353 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 354 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 355 // Data should use target endian. Code should always use little endian. 356 bool isBE = Arch == Triple::aarch64_be; 357 358 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 359 << format("%llx", Section.getAddressWithOffset(Offset)) 360 << " FinalAddress: 0x" << format("%llx", FinalAddress) 361 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 362 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend) 363 << "\n"); 364 365 switch (Type) { 366 default: 367 llvm_unreachable("Relocation type not implemented yet!"); 368 break; 369 case ELF::R_AARCH64_ABS64: 370 write(isBE, TargetPtr, Value + Addend); 371 break; 372 case ELF::R_AARCH64_PREL32: { 373 uint64_t Result = Value + Addend - FinalAddress; 374 assert(static_cast<int64_t>(Result) >= INT32_MIN && 375 static_cast<int64_t>(Result) <= UINT32_MAX); 376 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); 377 break; 378 } 379 case ELF::R_AARCH64_PREL64: 380 write(isBE, TargetPtr, Value + Addend - FinalAddress); 381 break; 382 case ELF::R_AARCH64_CALL26: // fallthrough 383 case ELF::R_AARCH64_JUMP26: { 384 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 385 // calculation. 386 uint64_t BranchImm = Value + Addend - FinalAddress; 387 388 // "Check that -2^27 <= result < 2^27". 389 assert(isInt<28>(BranchImm)); 390 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); 391 break; 392 } 393 case ELF::R_AARCH64_MOVW_UABS_G3: 394 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); 395 break; 396 case ELF::R_AARCH64_MOVW_UABS_G2_NC: 397 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); 398 break; 399 case ELF::R_AARCH64_MOVW_UABS_G1_NC: 400 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); 401 break; 402 case ELF::R_AARCH64_MOVW_UABS_G0_NC: 403 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); 404 break; 405 case ELF::R_AARCH64_ADR_PREL_PG_HI21: { 406 // Operation: Page(S+A) - Page(P) 407 uint64_t Result = 408 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); 409 410 // Check that -2^32 <= X < 2^32 411 assert(isInt<33>(Result) && "overflow check failed for relocation"); 412 413 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 414 // from bits 32:12 of X. 415 write32AArch64Addr(TargetPtr, Result >> 12); 416 break; 417 } 418 case ELF::R_AARCH64_ADD_ABS_LO12_NC: 419 // Operation: S + A 420 // Immediate goes in bits 21:10 of LD/ST instruction, taken 421 // from bits 11:0 of X 422 or32AArch64Imm(TargetPtr, Value + Addend); 423 break; 424 case ELF::R_AARCH64_LDST8_ABS_LO12_NC: 425 // Operation: S + A 426 // Immediate goes in bits 21:10 of LD/ST instruction, taken 427 // from bits 11:0 of X 428 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); 429 break; 430 case ELF::R_AARCH64_LDST16_ABS_LO12_NC: 431 // Operation: S + A 432 // Immediate goes in bits 21:10 of LD/ST instruction, taken 433 // from bits 11:1 of X 434 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); 435 break; 436 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: 437 // Operation: S + A 438 // Immediate goes in bits 21:10 of LD/ST instruction, taken 439 // from bits 11:2 of X 440 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); 441 break; 442 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: 443 // Operation: S + A 444 // Immediate goes in bits 21:10 of LD/ST instruction, taken 445 // from bits 11:3 of X 446 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); 447 break; 448 case ELF::R_AARCH64_LDST128_ABS_LO12_NC: 449 // Operation: S + A 450 // Immediate goes in bits 21:10 of LD/ST instruction, taken 451 // from bits 11:4 of X 452 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); 453 break; 454 } 455 } 456 457 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 458 uint64_t Offset, uint32_t Value, 459 uint32_t Type, int32_t Addend) { 460 // TODO: Add Thumb relocations. 461 uint32_t *TargetPtr = 462 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); 463 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; 464 Value += Addend; 465 466 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 467 << Section.getAddressWithOffset(Offset) 468 << " FinalAddress: " << format("%p", FinalAddress) << " Value: " 469 << format("%x", Value) << " Type: " << format("%x", Type) 470 << " Addend: " << format("%x", Addend) << "\n"); 471 472 switch (Type) { 473 default: 474 llvm_unreachable("Not implemented relocation type!"); 475 476 case ELF::R_ARM_NONE: 477 break; 478 // Write a 31bit signed offset 479 case ELF::R_ARM_PREL31: 480 support::ulittle32_t::ref{TargetPtr} = 481 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | 482 ((Value - FinalAddress) & ~0x80000000); 483 break; 484 case ELF::R_ARM_TARGET1: 485 case ELF::R_ARM_ABS32: 486 support::ulittle32_t::ref{TargetPtr} = Value; 487 break; 488 // Write first 16 bit of 32 bit value to the mov instruction. 489 // Last 4 bit should be shifted. 490 case ELF::R_ARM_MOVW_ABS_NC: 491 case ELF::R_ARM_MOVT_ABS: 492 if (Type == ELF::R_ARM_MOVW_ABS_NC) 493 Value = Value & 0xFFFF; 494 else if (Type == ELF::R_ARM_MOVT_ABS) 495 Value = (Value >> 16) & 0xFFFF; 496 support::ulittle32_t::ref{TargetPtr} = 497 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | 498 (((Value >> 12) & 0xF) << 16); 499 break; 500 // Write 24 bit relative value to the branch instruction. 501 case ELF::R_ARM_PC24: // Fall through. 502 case ELF::R_ARM_CALL: // Fall through. 503 case ELF::R_ARM_JUMP24: 504 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 505 RelValue = (RelValue & 0x03FFFFFC) >> 2; 506 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); 507 support::ulittle32_t::ref{TargetPtr} = 508 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; 509 break; 510 } 511 } 512 513 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { 514 if (Arch == Triple::UnknownArch || 515 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { 516 IsMipsO32ABI = false; 517 IsMipsN32ABI = false; 518 IsMipsN64ABI = false; 519 return; 520 } 521 unsigned AbiVariant; 522 Obj.getPlatformFlags(AbiVariant); 523 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; 524 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; 525 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); 526 } 527 528 // Return the .TOC. section and offset. 529 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, 530 ObjSectionToIDMap &LocalSections, 531 RelocationValueRef &Rel) { 532 // Set a default SectionID in case we do not find a TOC section below. 533 // This may happen for references to TOC base base (sym@toc, .odp 534 // relocation) without a .toc directive. In this case just use the 535 // first section (which is usually the .odp) since the code won't 536 // reference the .toc base directly. 537 Rel.SymbolName = nullptr; 538 Rel.SectionID = 0; 539 540 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 541 // order. The TOC starts where the first of these sections starts. 542 for (auto &Section: Obj.sections()) { 543 StringRef SectionName; 544 if (auto EC = Section.getName(SectionName)) 545 return errorCodeToError(EC); 546 547 if (SectionName == ".got" 548 || SectionName == ".toc" 549 || SectionName == ".tocbss" 550 || SectionName == ".plt") { 551 if (auto SectionIDOrErr = 552 findOrEmitSection(Obj, Section, false, LocalSections)) 553 Rel.SectionID = *SectionIDOrErr; 554 else 555 return SectionIDOrErr.takeError(); 556 break; 557 } 558 } 559 560 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 561 // thus permitting a full 64 Kbytes segment. 562 Rel.Addend = 0x8000; 563 564 return Error::success(); 565 } 566 567 // Returns the sections and offset associated with the ODP entry referenced 568 // by Symbol. 569 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, 570 ObjSectionToIDMap &LocalSections, 571 RelocationValueRef &Rel) { 572 // Get the ELF symbol value (st_value) to compare with Relocation offset in 573 // .opd entries 574 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 575 si != se; ++si) { 576 section_iterator RelSecI = si->getRelocatedSection(); 577 if (RelSecI == Obj.section_end()) 578 continue; 579 580 StringRef RelSectionName; 581 if (auto EC = RelSecI->getName(RelSectionName)) 582 return errorCodeToError(EC); 583 584 if (RelSectionName != ".opd") 585 continue; 586 587 for (elf_relocation_iterator i = si->relocation_begin(), 588 e = si->relocation_end(); 589 i != e;) { 590 // The R_PPC64_ADDR64 relocation indicates the first field 591 // of a .opd entry 592 uint64_t TypeFunc = i->getType(); 593 if (TypeFunc != ELF::R_PPC64_ADDR64) { 594 ++i; 595 continue; 596 } 597 598 uint64_t TargetSymbolOffset = i->getOffset(); 599 symbol_iterator TargetSymbol = i->getSymbol(); 600 int64_t Addend; 601 if (auto AddendOrErr = i->getAddend()) 602 Addend = *AddendOrErr; 603 else 604 return errorCodeToError(AddendOrErr.getError()); 605 606 ++i; 607 if (i == e) 608 break; 609 610 // Just check if following relocation is a R_PPC64_TOC 611 uint64_t TypeTOC = i->getType(); 612 if (TypeTOC != ELF::R_PPC64_TOC) 613 continue; 614 615 // Finally compares the Symbol value and the target symbol offset 616 // to check if this .opd entry refers to the symbol the relocation 617 // points to. 618 if (Rel.Addend != (int64_t)TargetSymbolOffset) 619 continue; 620 621 section_iterator TSI = Obj.section_end(); 622 if (auto TSIOrErr = TargetSymbol->getSection()) 623 TSI = *TSIOrErr; 624 else 625 return TSIOrErr.takeError(); 626 assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); 627 628 bool IsCode = TSI->isText(); 629 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, 630 LocalSections)) 631 Rel.SectionID = *SectionIDOrErr; 632 else 633 return SectionIDOrErr.takeError(); 634 Rel.Addend = (intptr_t)Addend; 635 return Error::success(); 636 } 637 } 638 llvm_unreachable("Attempting to get address of ODP entry!"); 639 } 640 641 // Relocation masks following the #lo(value), #hi(value), #ha(value), 642 // #higher(value), #highera(value), #highest(value), and #highesta(value) 643 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 644 // document. 645 646 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 647 648 static inline uint16_t applyPPChi(uint64_t value) { 649 return (value >> 16) & 0xffff; 650 } 651 652 static inline uint16_t applyPPCha (uint64_t value) { 653 return ((value + 0x8000) >> 16) & 0xffff; 654 } 655 656 static inline uint16_t applyPPChigher(uint64_t value) { 657 return (value >> 32) & 0xffff; 658 } 659 660 static inline uint16_t applyPPChighera (uint64_t value) { 661 return ((value + 0x8000) >> 32) & 0xffff; 662 } 663 664 static inline uint16_t applyPPChighest(uint64_t value) { 665 return (value >> 48) & 0xffff; 666 } 667 668 static inline uint16_t applyPPChighesta (uint64_t value) { 669 return ((value + 0x8000) >> 48) & 0xffff; 670 } 671 672 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, 673 uint64_t Offset, uint64_t Value, 674 uint32_t Type, int64_t Addend) { 675 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 676 switch (Type) { 677 default: 678 llvm_unreachable("Relocation type not implemented yet!"); 679 break; 680 case ELF::R_PPC_ADDR16_LO: 681 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 682 break; 683 case ELF::R_PPC_ADDR16_HI: 684 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 685 break; 686 case ELF::R_PPC_ADDR16_HA: 687 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 688 break; 689 } 690 } 691 692 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 693 uint64_t Offset, uint64_t Value, 694 uint32_t Type, int64_t Addend) { 695 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 696 switch (Type) { 697 default: 698 llvm_unreachable("Relocation type not implemented yet!"); 699 break; 700 case ELF::R_PPC64_ADDR16: 701 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 702 break; 703 case ELF::R_PPC64_ADDR16_DS: 704 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 705 break; 706 case ELF::R_PPC64_ADDR16_LO: 707 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 708 break; 709 case ELF::R_PPC64_ADDR16_LO_DS: 710 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 711 break; 712 case ELF::R_PPC64_ADDR16_HI: 713 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 714 break; 715 case ELF::R_PPC64_ADDR16_HA: 716 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 717 break; 718 case ELF::R_PPC64_ADDR16_HIGHER: 719 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 720 break; 721 case ELF::R_PPC64_ADDR16_HIGHERA: 722 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 723 break; 724 case ELF::R_PPC64_ADDR16_HIGHEST: 725 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 726 break; 727 case ELF::R_PPC64_ADDR16_HIGHESTA: 728 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 729 break; 730 case ELF::R_PPC64_ADDR14: { 731 assert(((Value + Addend) & 3) == 0); 732 // Preserve the AA/LK bits in the branch instruction 733 uint8_t aalk = *(LocalAddress + 3); 734 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 735 } break; 736 case ELF::R_PPC64_REL16_LO: { 737 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 738 uint64_t Delta = Value - FinalAddress + Addend; 739 writeInt16BE(LocalAddress, applyPPClo(Delta)); 740 } break; 741 case ELF::R_PPC64_REL16_HI: { 742 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 743 uint64_t Delta = Value - FinalAddress + Addend; 744 writeInt16BE(LocalAddress, applyPPChi(Delta)); 745 } break; 746 case ELF::R_PPC64_REL16_HA: { 747 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 748 uint64_t Delta = Value - FinalAddress + Addend; 749 writeInt16BE(LocalAddress, applyPPCha(Delta)); 750 } break; 751 case ELF::R_PPC64_ADDR32: { 752 int32_t Result = static_cast<int32_t>(Value + Addend); 753 if (SignExtend32<32>(Result) != Result) 754 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 755 writeInt32BE(LocalAddress, Result); 756 } break; 757 case ELF::R_PPC64_REL24: { 758 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 759 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 760 if (SignExtend32<26>(delta) != delta) 761 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 762 // Generates a 'bl <address>' instruction 763 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); 764 } break; 765 case ELF::R_PPC64_REL32: { 766 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 767 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 768 if (SignExtend32<32>(delta) != delta) 769 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 770 writeInt32BE(LocalAddress, delta); 771 } break; 772 case ELF::R_PPC64_REL64: { 773 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); 774 uint64_t Delta = Value - FinalAddress + Addend; 775 writeInt64BE(LocalAddress, Delta); 776 } break; 777 case ELF::R_PPC64_ADDR64: 778 writeInt64BE(LocalAddress, Value + Addend); 779 break; 780 } 781 } 782 783 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 784 uint64_t Offset, uint64_t Value, 785 uint32_t Type, int64_t Addend) { 786 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); 787 switch (Type) { 788 default: 789 llvm_unreachable("Relocation type not implemented yet!"); 790 break; 791 case ELF::R_390_PC16DBL: 792 case ELF::R_390_PLT16DBL: { 793 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 794 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 795 writeInt16BE(LocalAddress, Delta / 2); 796 break; 797 } 798 case ELF::R_390_PC32DBL: 799 case ELF::R_390_PLT32DBL: { 800 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 801 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 802 writeInt32BE(LocalAddress, Delta / 2); 803 break; 804 } 805 case ELF::R_390_PC32: { 806 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 807 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 808 writeInt32BE(LocalAddress, Delta); 809 break; 810 } 811 case ELF::R_390_64: 812 writeInt64BE(LocalAddress, Value + Addend); 813 break; 814 case ELF::R_390_PC64: { 815 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); 816 writeInt64BE(LocalAddress, Delta); 817 break; 818 } 819 } 820 } 821 822 void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, 823 uint64_t Offset, uint64_t Value, 824 uint32_t Type, int64_t Addend) { 825 bool isBE = Arch == Triple::bpfeb; 826 827 switch (Type) { 828 default: 829 llvm_unreachable("Relocation type not implemented yet!"); 830 break; 831 case ELF::R_BPF_NONE: 832 break; 833 case ELF::R_BPF_64_64: { 834 write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); 835 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 836 << format("%p\n", Section.getAddressWithOffset(Offset))); 837 break; 838 } 839 case ELF::R_BPF_64_32: { 840 Value += Addend; 841 assert(Value <= UINT32_MAX); 842 write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); 843 DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " 844 << format("%p\n", Section.getAddressWithOffset(Offset))); 845 break; 846 } 847 } 848 } 849 850 // The target location for the relocation is described by RE.SectionID and 851 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 852 // SectionEntry has three members describing its location. 853 // SectionEntry::Address is the address at which the section has been loaded 854 // into memory in the current (host) process. SectionEntry::LoadAddress is the 855 // address that the section will have in the target process. 856 // SectionEntry::ObjAddress is the address of the bits for this section in the 857 // original emitted object image (also in the current address space). 858 // 859 // Relocations will be applied as if the section were loaded at 860 // SectionEntry::LoadAddress, but they will be applied at an address based 861 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 862 // Target memory contents if they are required for value calculations. 863 // 864 // The Value parameter here is the load address of the symbol for the 865 // relocation to be applied. For relocations which refer to symbols in the 866 // current object Value will be the LoadAddress of the section in which 867 // the symbol resides (RE.Addend provides additional information about the 868 // symbol location). For external symbols, Value will be the address of the 869 // symbol in the target address space. 870 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 871 uint64_t Value) { 872 const SectionEntry &Section = Sections[RE.SectionID]; 873 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 874 RE.SymOffset, RE.SectionID); 875 } 876 877 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 878 uint64_t Offset, uint64_t Value, 879 uint32_t Type, int64_t Addend, 880 uint64_t SymOffset, SID SectionID) { 881 switch (Arch) { 882 case Triple::x86_64: 883 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 884 break; 885 case Triple::x86: 886 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 887 (uint32_t)(Addend & 0xffffffffL)); 888 break; 889 case Triple::aarch64: 890 case Triple::aarch64_be: 891 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 892 break; 893 case Triple::arm: // Fall through. 894 case Triple::armeb: 895 case Triple::thumb: 896 case Triple::thumbeb: 897 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 898 (uint32_t)(Addend & 0xffffffffL)); 899 break; 900 case Triple::ppc: 901 resolvePPC32Relocation(Section, Offset, Value, Type, Addend); 902 break; 903 case Triple::ppc64: // Fall through. 904 case Triple::ppc64le: 905 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 906 break; 907 case Triple::systemz: 908 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 909 break; 910 case Triple::bpfel: 911 case Triple::bpfeb: 912 resolveBPFRelocation(Section, Offset, Value, Type, Addend); 913 break; 914 default: 915 llvm_unreachable("Unsupported CPU type!"); 916 } 917 } 918 919 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { 920 return (void *)(Sections[SectionID].getObjAddress() + Offset); 921 } 922 923 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { 924 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 925 if (Value.SymbolName) 926 addRelocationForSymbol(RE, Value.SymbolName); 927 else 928 addRelocationForSection(RE, Value.SectionID); 929 } 930 931 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, 932 bool IsLocal) const { 933 switch (RelType) { 934 case ELF::R_MICROMIPS_GOT16: 935 if (IsLocal) 936 return ELF::R_MICROMIPS_LO16; 937 break; 938 case ELF::R_MICROMIPS_HI16: 939 return ELF::R_MICROMIPS_LO16; 940 case ELF::R_MIPS_GOT16: 941 if (IsLocal) 942 return ELF::R_MIPS_LO16; 943 break; 944 case ELF::R_MIPS_HI16: 945 return ELF::R_MIPS_LO16; 946 case ELF::R_MIPS_PCHI16: 947 return ELF::R_MIPS_PCLO16; 948 default: 949 break; 950 } 951 return ELF::R_MIPS_NONE; 952 } 953 954 // Sometimes we don't need to create thunk for a branch. 955 // This typically happens when branch target is located 956 // in the same object file. In such case target is either 957 // a weak symbol or symbol in a different executable section. 958 // This function checks if branch target is located in the 959 // same object file and if distance between source and target 960 // fits R_AARCH64_CALL26 relocation. If both conditions are 961 // met, it emits direct jump to the target and returns true. 962 // Otherwise false is returned and thunk is created. 963 bool RuntimeDyldELF::resolveAArch64ShortBranch( 964 unsigned SectionID, relocation_iterator RelI, 965 const RelocationValueRef &Value) { 966 uint64_t Address; 967 if (Value.SymbolName) { 968 auto Loc = GlobalSymbolTable.find(Value.SymbolName); 969 970 // Don't create direct branch for external symbols. 971 if (Loc == GlobalSymbolTable.end()) 972 return false; 973 974 const auto &SymInfo = Loc->second; 975 Address = 976 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( 977 SymInfo.getOffset())); 978 } else { 979 Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); 980 } 981 uint64_t Offset = RelI->getOffset(); 982 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); 983 984 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 985 // If distance between source and target is out of range then we should 986 // create thunk. 987 if (!isInt<28>(Address + Value.Addend - SourceAddress)) 988 return false; 989 990 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), 991 Value.Addend); 992 993 return true; 994 } 995 996 void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, 997 const RelocationValueRef &Value, 998 relocation_iterator RelI, 999 StubMap &Stubs) { 1000 1001 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 1002 SectionEntry &Section = Sections[SectionID]; 1003 1004 uint64_t Offset = RelI->getOffset(); 1005 unsigned RelType = RelI->getType(); 1006 // Look for an existing stub. 1007 StubMap::const_iterator i = Stubs.find(Value); 1008 if (i != Stubs.end()) { 1009 resolveRelocation(Section, Offset, 1010 (uint64_t)Section.getAddressWithOffset(i->second), 1011 RelType, 0); 1012 DEBUG(dbgs() << " Stub function found\n"); 1013 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { 1014 // Create a new stub function. 1015 DEBUG(dbgs() << " Create a new stub function\n"); 1016 Stubs[Value] = Section.getStubOffset(); 1017 uint8_t *StubTargetAddr = createStubFunction( 1018 Section.getAddressWithOffset(Section.getStubOffset())); 1019 1020 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), 1021 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 1022 RelocationEntry REmovk_g2(SectionID, 1023 StubTargetAddr - Section.getAddress() + 4, 1024 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 1025 RelocationEntry REmovk_g1(SectionID, 1026 StubTargetAddr - Section.getAddress() + 8, 1027 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 1028 RelocationEntry REmovk_g0(SectionID, 1029 StubTargetAddr - Section.getAddress() + 12, 1030 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 1031 1032 if (Value.SymbolName) { 1033 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 1034 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 1035 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 1036 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 1037 } else { 1038 addRelocationForSection(REmovz_g3, Value.SectionID); 1039 addRelocationForSection(REmovk_g2, Value.SectionID); 1040 addRelocationForSection(REmovk_g1, Value.SectionID); 1041 addRelocationForSection(REmovk_g0, Value.SectionID); 1042 } 1043 resolveRelocation(Section, Offset, 1044 reinterpret_cast<uint64_t>(Section.getAddressWithOffset( 1045 Section.getStubOffset())), 1046 RelType, 0); 1047 Section.advanceStubOffset(getMaxStubSize()); 1048 } 1049 } 1050 1051 Expected<relocation_iterator> 1052 RuntimeDyldELF::processRelocationRef( 1053 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, 1054 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { 1055 const auto &Obj = cast<ELFObjectFileBase>(O); 1056 uint64_t RelType = RelI->getType(); 1057 ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend(); 1058 int64_t Addend = AddendOrErr ? *AddendOrErr : 0; 1059 elf_symbol_iterator Symbol = RelI->getSymbol(); 1060 1061 // Obtain the symbol name which is referenced in the relocation 1062 StringRef TargetName; 1063 if (Symbol != Obj.symbol_end()) { 1064 if (auto TargetNameOrErr = Symbol->getName()) 1065 TargetName = *TargetNameOrErr; 1066 else 1067 return TargetNameOrErr.takeError(); 1068 } 1069 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 1070 << " TargetName: " << TargetName << "\n"); 1071 RelocationValueRef Value; 1072 // First search for the symbol in the local symbol table 1073 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 1074 1075 // Search for the symbol in the global symbol table 1076 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 1077 if (Symbol != Obj.symbol_end()) { 1078 gsi = GlobalSymbolTable.find(TargetName.data()); 1079 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); 1080 if (!SymTypeOrErr) { 1081 std::string Buf; 1082 raw_string_ostream OS(Buf); 1083 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, ""); 1084 OS.flush(); 1085 report_fatal_error(Buf); 1086 } 1087 SymType = *SymTypeOrErr; 1088 } 1089 if (gsi != GlobalSymbolTable.end()) { 1090 const auto &SymInfo = gsi->second; 1091 Value.SectionID = SymInfo.getSectionID(); 1092 Value.Offset = SymInfo.getOffset(); 1093 Value.Addend = SymInfo.getOffset() + Addend; 1094 } else { 1095 switch (SymType) { 1096 case SymbolRef::ST_Debug: { 1097 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 1098 // and can be changed by another developers. Maybe best way is add 1099 // a new symbol type ST_Section to SymbolRef and use it. 1100 auto SectionOrErr = Symbol->getSection(); 1101 if (!SectionOrErr) { 1102 std::string Buf; 1103 raw_string_ostream OS(Buf); 1104 logAllUnhandledErrors(SectionOrErr.takeError(), OS, ""); 1105 OS.flush(); 1106 report_fatal_error(Buf); 1107 } 1108 section_iterator si = *SectionOrErr; 1109 if (si == Obj.section_end()) 1110 llvm_unreachable("Symbol section not found, bad object file format!"); 1111 DEBUG(dbgs() << "\t\tThis is section symbol\n"); 1112 bool isCode = si->isText(); 1113 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, 1114 ObjSectionToID)) 1115 Value.SectionID = *SectionIDOrErr; 1116 else 1117 return SectionIDOrErr.takeError(); 1118 Value.Addend = Addend; 1119 break; 1120 } 1121 case SymbolRef::ST_Data: 1122 case SymbolRef::ST_Function: 1123 case SymbolRef::ST_Unknown: { 1124 Value.SymbolName = TargetName.data(); 1125 Value.Addend = Addend; 1126 1127 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 1128 // will manifest here as a NULL symbol name. 1129 // We can set this as a valid (but empty) symbol name, and rely 1130 // on addRelocationForSymbol to handle this. 1131 if (!Value.SymbolName) 1132 Value.SymbolName = ""; 1133 break; 1134 } 1135 default: 1136 llvm_unreachable("Unresolved symbol type!"); 1137 break; 1138 } 1139 } 1140 1141 uint64_t Offset = RelI->getOffset(); 1142 1143 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 1144 << "\n"); 1145 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { 1146 if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { 1147 resolveAArch64Branch(SectionID, Value, RelI, Stubs); 1148 } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { 1149 // Craete new GOT entry or find existing one. If GOT entry is 1150 // to be created, then we also emit ABS64 relocation for it. 1151 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1152 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1153 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1154 1155 } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { 1156 uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); 1157 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1158 ELF::R_AARCH64_LDST64_ABS_LO12_NC); 1159 } else { 1160 processSimpleRelocation(SectionID, Offset, RelType, Value); 1161 } 1162 } else if (Arch == Triple::arm) { 1163 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1164 RelType == ELF::R_ARM_JUMP24) { 1165 // This is an ARM branch relocation, need to use a stub function. 1166 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); 1167 SectionEntry &Section = Sections[SectionID]; 1168 1169 // Look for an existing stub. 1170 StubMap::const_iterator i = Stubs.find(Value); 1171 if (i != Stubs.end()) { 1172 resolveRelocation( 1173 Section, Offset, 1174 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), 1175 RelType, 0); 1176 DEBUG(dbgs() << " Stub function found\n"); 1177 } else { 1178 // Create a new stub function. 1179 DEBUG(dbgs() << " Create a new stub function\n"); 1180 Stubs[Value] = Section.getStubOffset(); 1181 uint8_t *StubTargetAddr = createStubFunction( 1182 Section.getAddressWithOffset(Section.getStubOffset())); 1183 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1184 ELF::R_ARM_ABS32, Value.Addend); 1185 if (Value.SymbolName) 1186 addRelocationForSymbol(RE, Value.SymbolName); 1187 else 1188 addRelocationForSection(RE, Value.SectionID); 1189 1190 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1191 Section.getAddressWithOffset( 1192 Section.getStubOffset())), 1193 RelType, 0); 1194 Section.advanceStubOffset(getMaxStubSize()); 1195 } 1196 } else { 1197 uint32_t *Placeholder = 1198 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); 1199 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || 1200 RelType == ELF::R_ARM_ABS32) { 1201 Value.Addend += *Placeholder; 1202 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { 1203 // See ELF for ARM documentation 1204 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); 1205 } 1206 processSimpleRelocation(SectionID, Offset, RelType, Value); 1207 } 1208 } else if (IsMipsO32ABI) { 1209 uint8_t *Placeholder = reinterpret_cast<uint8_t *>( 1210 computePlaceholderAddress(SectionID, Offset)); 1211 uint32_t Opcode = readBytesUnaligned(Placeholder, 4); 1212 if (RelType == ELF::R_MIPS_26) { 1213 // This is an Mips branch relocation, need to use a stub function. 1214 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1215 SectionEntry &Section = Sections[SectionID]; 1216 1217 // Extract the addend from the instruction. 1218 // We shift up by two since the Value will be down shifted again 1219 // when applying the relocation. 1220 uint32_t Addend = (Opcode & 0x03ffffff) << 2; 1221 1222 Value.Addend += Addend; 1223 1224 // Look up for existing stub. 1225 StubMap::const_iterator i = Stubs.find(Value); 1226 if (i != Stubs.end()) { 1227 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1228 addRelocationForSection(RE, SectionID); 1229 DEBUG(dbgs() << " Stub function found\n"); 1230 } else { 1231 // Create a new stub function. 1232 DEBUG(dbgs() << " Create a new stub function\n"); 1233 Stubs[Value] = Section.getStubOffset(); 1234 1235 unsigned AbiVariant; 1236 O.getPlatformFlags(AbiVariant); 1237 1238 uint8_t *StubTargetAddr = createStubFunction( 1239 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); 1240 1241 // Creating Hi and Lo relocations for the filled stub instructions. 1242 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), 1243 ELF::R_MIPS_HI16, Value.Addend); 1244 RelocationEntry RELo(SectionID, 1245 StubTargetAddr - Section.getAddress() + 4, 1246 ELF::R_MIPS_LO16, Value.Addend); 1247 1248 if (Value.SymbolName) { 1249 addRelocationForSymbol(REHi, Value.SymbolName); 1250 addRelocationForSymbol(RELo, Value.SymbolName); 1251 } 1252 else { 1253 addRelocationForSection(REHi, Value.SectionID); 1254 addRelocationForSection(RELo, Value.SectionID); 1255 } 1256 1257 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); 1258 addRelocationForSection(RE, SectionID); 1259 Section.advanceStubOffset(getMaxStubSize()); 1260 } 1261 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { 1262 int64_t Addend = (Opcode & 0x0000ffff) << 16; 1263 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1264 PendingRelocs.push_back(std::make_pair(Value, RE)); 1265 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { 1266 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); 1267 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { 1268 const RelocationValueRef &MatchingValue = I->first; 1269 RelocationEntry &Reloc = I->second; 1270 if (MatchingValue == Value && 1271 RelType == getMatchingLoRelocation(Reloc.RelType) && 1272 SectionID == Reloc.SectionID) { 1273 Reloc.Addend += Addend; 1274 if (Value.SymbolName) 1275 addRelocationForSymbol(Reloc, Value.SymbolName); 1276 else 1277 addRelocationForSection(Reloc, Value.SectionID); 1278 I = PendingRelocs.erase(I); 1279 } else 1280 ++I; 1281 } 1282 RelocationEntry RE(SectionID, Offset, RelType, Addend); 1283 if (Value.SymbolName) 1284 addRelocationForSymbol(RE, Value.SymbolName); 1285 else 1286 addRelocationForSection(RE, Value.SectionID); 1287 } else { 1288 if (RelType == ELF::R_MIPS_32) 1289 Value.Addend += Opcode; 1290 else if (RelType == ELF::R_MIPS_PC16) 1291 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); 1292 else if (RelType == ELF::R_MIPS_PC19_S2) 1293 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); 1294 else if (RelType == ELF::R_MIPS_PC21_S2) 1295 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); 1296 else if (RelType == ELF::R_MIPS_PC26_S2) 1297 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); 1298 processSimpleRelocation(SectionID, Offset, RelType, Value); 1299 } 1300 } else if (IsMipsN32ABI || IsMipsN64ABI) { 1301 uint32_t r_type = RelType & 0xff; 1302 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1303 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE 1304 || r_type == ELF::R_MIPS_GOT_DISP) { 1305 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); 1306 if (i != GOTSymbolOffsets.end()) 1307 RE.SymOffset = i->second; 1308 else { 1309 RE.SymOffset = allocateGOTEntries(1); 1310 GOTSymbolOffsets[TargetName] = RE.SymOffset; 1311 } 1312 } 1313 if (Value.SymbolName) 1314 addRelocationForSymbol(RE, Value.SymbolName); 1315 else 1316 addRelocationForSection(RE, Value.SectionID); 1317 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1318 if (RelType == ELF::R_PPC64_REL24) { 1319 // Determine ABI variant in use for this object. 1320 unsigned AbiVariant; 1321 Obj.getPlatformFlags(AbiVariant); 1322 AbiVariant &= ELF::EF_PPC64_ABI; 1323 // A PPC branch relocation will need a stub function if the target is 1324 // an external symbol (Symbol::ST_Unknown) or if the target address 1325 // is not within the signed 24-bits branch address. 1326 SectionEntry &Section = Sections[SectionID]; 1327 uint8_t *Target = Section.getAddressWithOffset(Offset); 1328 bool RangeOverflow = false; 1329 if (SymType != SymbolRef::ST_Unknown) { 1330 if (AbiVariant != 2) { 1331 // In the ELFv1 ABI, a function call may point to the .opd entry, 1332 // so the final symbol value is calculated based on the relocation 1333 // values in the .opd section. 1334 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) 1335 return std::move(Err); 1336 } else { 1337 // In the ELFv2 ABI, a function symbol may provide a local entry 1338 // point, which must be used for direct calls. 1339 uint8_t SymOther = Symbol->getOther(); 1340 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1341 } 1342 uint8_t *RelocTarget = 1343 Sections[Value.SectionID].getAddressWithOffset(Value.Addend); 1344 int32_t delta = static_cast<int32_t>(Target - RelocTarget); 1345 // If it is within 26-bits branch range, just set the branch target 1346 if (SignExtend32<26>(delta) == delta) { 1347 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1348 if (Value.SymbolName) 1349 addRelocationForSymbol(RE, Value.SymbolName); 1350 else 1351 addRelocationForSection(RE, Value.SectionID); 1352 } else { 1353 RangeOverflow = true; 1354 } 1355 } 1356 if (SymType == SymbolRef::ST_Unknown || RangeOverflow) { 1357 // It is an external symbol (SymbolRef::ST_Unknown) or within a range 1358 // larger than 24-bits. 1359 StubMap::const_iterator i = Stubs.find(Value); 1360 if (i != Stubs.end()) { 1361 // Symbol function stub already created, just relocate to it 1362 resolveRelocation(Section, Offset, 1363 reinterpret_cast<uint64_t>( 1364 Section.getAddressWithOffset(i->second)), 1365 RelType, 0); 1366 DEBUG(dbgs() << " Stub function found\n"); 1367 } else { 1368 // Create a new stub function. 1369 DEBUG(dbgs() << " Create a new stub function\n"); 1370 Stubs[Value] = Section.getStubOffset(); 1371 uint8_t *StubTargetAddr = createStubFunction( 1372 Section.getAddressWithOffset(Section.getStubOffset()), 1373 AbiVariant); 1374 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), 1375 ELF::R_PPC64_ADDR64, Value.Addend); 1376 1377 // Generates the 64-bits address loads as exemplified in section 1378 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1379 // apply to the low part of the instructions, so we have to update 1380 // the offset according to the target endianness. 1381 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); 1382 if (!IsTargetLittleEndian) 1383 StubRelocOffset += 2; 1384 1385 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1386 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1387 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1388 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1389 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1390 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1391 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1392 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1393 1394 if (Value.SymbolName) { 1395 addRelocationForSymbol(REhst, Value.SymbolName); 1396 addRelocationForSymbol(REhr, Value.SymbolName); 1397 addRelocationForSymbol(REh, Value.SymbolName); 1398 addRelocationForSymbol(REl, Value.SymbolName); 1399 } else { 1400 addRelocationForSection(REhst, Value.SectionID); 1401 addRelocationForSection(REhr, Value.SectionID); 1402 addRelocationForSection(REh, Value.SectionID); 1403 addRelocationForSection(REl, Value.SectionID); 1404 } 1405 1406 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( 1407 Section.getAddressWithOffset( 1408 Section.getStubOffset())), 1409 RelType, 0); 1410 Section.advanceStubOffset(getMaxStubSize()); 1411 } 1412 if (SymType == SymbolRef::ST_Unknown) { 1413 // Restore the TOC for external calls 1414 if (AbiVariant == 2) 1415 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1) 1416 else 1417 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1418 } 1419 } 1420 } else if (RelType == ELF::R_PPC64_TOC16 || 1421 RelType == ELF::R_PPC64_TOC16_DS || 1422 RelType == ELF::R_PPC64_TOC16_LO || 1423 RelType == ELF::R_PPC64_TOC16_LO_DS || 1424 RelType == ELF::R_PPC64_TOC16_HI || 1425 RelType == ELF::R_PPC64_TOC16_HA) { 1426 // These relocations are supposed to subtract the TOC address from 1427 // the final value. This does not fit cleanly into the RuntimeDyld 1428 // scheme, since there may be *two* sections involved in determining 1429 // the relocation value (the section of the symbol referred to by the 1430 // relocation, and the TOC section associated with the current module). 1431 // 1432 // Fortunately, these relocations are currently only ever generated 1433 // referring to symbols that themselves reside in the TOC, which means 1434 // that the two sections are actually the same. Thus they cancel out 1435 // and we can immediately resolve the relocation right now. 1436 switch (RelType) { 1437 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1438 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1439 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1440 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1441 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1442 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1443 default: llvm_unreachable("Wrong relocation type."); 1444 } 1445 1446 RelocationValueRef TOCValue; 1447 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) 1448 return std::move(Err); 1449 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1450 llvm_unreachable("Unsupported TOC relocation."); 1451 Value.Addend -= TOCValue.Addend; 1452 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1453 } else { 1454 // There are two ways to refer to the TOC address directly: either 1455 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1456 // ignored), or via any relocation that refers to the magic ".TOC." 1457 // symbols (in which case the addend is respected). 1458 if (RelType == ELF::R_PPC64_TOC) { 1459 RelType = ELF::R_PPC64_ADDR64; 1460 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1461 return std::move(Err); 1462 } else if (TargetName == ".TOC.") { 1463 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) 1464 return std::move(Err); 1465 Value.Addend += Addend; 1466 } 1467 1468 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1469 1470 if (Value.SymbolName) 1471 addRelocationForSymbol(RE, Value.SymbolName); 1472 else 1473 addRelocationForSection(RE, Value.SectionID); 1474 } 1475 } else if (Arch == Triple::systemz && 1476 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1477 // Create function stubs for both PLT and GOT references, regardless of 1478 // whether the GOT reference is to data or code. The stub contains the 1479 // full address of the symbol, as needed by GOT references, and the 1480 // executable part only adds an overhead of 8 bytes. 1481 // 1482 // We could try to conserve space by allocating the code and data 1483 // parts of the stub separately. However, as things stand, we allocate 1484 // a stub for every relocation, so using a GOT in JIT code should be 1485 // no less space efficient than using an explicit constant pool. 1486 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1487 SectionEntry &Section = Sections[SectionID]; 1488 1489 // Look for an existing stub. 1490 StubMap::const_iterator i = Stubs.find(Value); 1491 uintptr_t StubAddress; 1492 if (i != Stubs.end()) { 1493 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); 1494 DEBUG(dbgs() << " Stub function found\n"); 1495 } else { 1496 // Create a new stub function. 1497 DEBUG(dbgs() << " Create a new stub function\n"); 1498 1499 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1500 uintptr_t StubAlignment = getStubAlignment(); 1501 StubAddress = 1502 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1503 -StubAlignment; 1504 unsigned StubOffset = StubAddress - BaseAddress; 1505 1506 Stubs[Value] = StubOffset; 1507 createStubFunction((uint8_t *)StubAddress); 1508 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1509 Value.Offset); 1510 if (Value.SymbolName) 1511 addRelocationForSymbol(RE, Value.SymbolName); 1512 else 1513 addRelocationForSection(RE, Value.SectionID); 1514 Section.advanceStubOffset(getMaxStubSize()); 1515 } 1516 1517 if (RelType == ELF::R_390_GOTENT) 1518 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1519 Addend); 1520 else 1521 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1522 } else if (Arch == Triple::x86_64) { 1523 if (RelType == ELF::R_X86_64_PLT32) { 1524 // The way the PLT relocations normally work is that the linker allocates 1525 // the 1526 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1527 // entry will then jump to an address provided by the GOT. On first call, 1528 // the 1529 // GOT address will point back into PLT code that resolves the symbol. After 1530 // the first call, the GOT entry points to the actual function. 1531 // 1532 // For local functions we're ignoring all of that here and just replacing 1533 // the PLT32 relocation type with PC32, which will translate the relocation 1534 // into a PC-relative call directly to the function. For external symbols we 1535 // can't be sure the function will be within 2^32 bytes of the call site, so 1536 // we need to create a stub, which calls into the GOT. This case is 1537 // equivalent to the usual PLT implementation except that we use the stub 1538 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1539 // rather than allocating a PLT section. 1540 if (Value.SymbolName) { 1541 // This is a call to an external function. 1542 // Look for an existing stub. 1543 SectionEntry &Section = Sections[SectionID]; 1544 StubMap::const_iterator i = Stubs.find(Value); 1545 uintptr_t StubAddress; 1546 if (i != Stubs.end()) { 1547 StubAddress = uintptr_t(Section.getAddress()) + i->second; 1548 DEBUG(dbgs() << " Stub function found\n"); 1549 } else { 1550 // Create a new stub function (equivalent to a PLT entry). 1551 DEBUG(dbgs() << " Create a new stub function\n"); 1552 1553 uintptr_t BaseAddress = uintptr_t(Section.getAddress()); 1554 uintptr_t StubAlignment = getStubAlignment(); 1555 StubAddress = 1556 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & 1557 -StubAlignment; 1558 unsigned StubOffset = StubAddress - BaseAddress; 1559 Stubs[Value] = StubOffset; 1560 createStubFunction((uint8_t *)StubAddress); 1561 1562 // Bump our stub offset counter 1563 Section.advanceStubOffset(getMaxStubSize()); 1564 1565 // Allocate a GOT Entry 1566 uint64_t GOTOffset = allocateGOTEntries(1); 1567 1568 // The load of the GOT address has an addend of -4 1569 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, 1570 ELF::R_X86_64_PC32); 1571 1572 // Fill in the value of the symbol we're targeting into the GOT 1573 addRelocationForSymbol( 1574 computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), 1575 Value.SymbolName); 1576 } 1577 1578 // Make the target call a call into the stub table. 1579 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1580 Addend); 1581 } else { 1582 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1583 Value.Offset); 1584 addRelocationForSection(RE, Value.SectionID); 1585 } 1586 } else if (RelType == ELF::R_X86_64_GOTPCREL || 1587 RelType == ELF::R_X86_64_GOTPCRELX || 1588 RelType == ELF::R_X86_64_REX_GOTPCRELX) { 1589 uint64_t GOTOffset = allocateGOTEntries(1); 1590 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, 1591 ELF::R_X86_64_PC32); 1592 1593 // Fill in the value of the symbol we're targeting into the GOT 1594 RelocationEntry RE = 1595 computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); 1596 if (Value.SymbolName) 1597 addRelocationForSymbol(RE, Value.SymbolName); 1598 else 1599 addRelocationForSection(RE, Value.SectionID); 1600 } else if (RelType == ELF::R_X86_64_PC32) { 1601 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1602 processSimpleRelocation(SectionID, Offset, RelType, Value); 1603 } else if (RelType == ELF::R_X86_64_PC64) { 1604 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); 1605 processSimpleRelocation(SectionID, Offset, RelType, Value); 1606 } else { 1607 processSimpleRelocation(SectionID, Offset, RelType, Value); 1608 } 1609 } else { 1610 if (Arch == Triple::x86) { 1611 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); 1612 } 1613 processSimpleRelocation(SectionID, Offset, RelType, Value); 1614 } 1615 return ++RelI; 1616 } 1617 1618 size_t RuntimeDyldELF::getGOTEntrySize() { 1619 // We don't use the GOT in all of these cases, but it's essentially free 1620 // to put them all here. 1621 size_t Result = 0; 1622 switch (Arch) { 1623 case Triple::x86_64: 1624 case Triple::aarch64: 1625 case Triple::aarch64_be: 1626 case Triple::ppc64: 1627 case Triple::ppc64le: 1628 case Triple::systemz: 1629 Result = sizeof(uint64_t); 1630 break; 1631 case Triple::x86: 1632 case Triple::arm: 1633 case Triple::thumb: 1634 Result = sizeof(uint32_t); 1635 break; 1636 case Triple::mips: 1637 case Triple::mipsel: 1638 case Triple::mips64: 1639 case Triple::mips64el: 1640 if (IsMipsO32ABI || IsMipsN32ABI) 1641 Result = sizeof(uint32_t); 1642 else if (IsMipsN64ABI) 1643 Result = sizeof(uint64_t); 1644 else 1645 llvm_unreachable("Mips ABI not handled"); 1646 break; 1647 default: 1648 llvm_unreachable("Unsupported CPU type!"); 1649 } 1650 return Result; 1651 } 1652 1653 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { 1654 if (GOTSectionID == 0) { 1655 GOTSectionID = Sections.size(); 1656 // Reserve a section id. We'll allocate the section later 1657 // once we know the total size 1658 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); 1659 } 1660 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1661 CurrentGOTIndex += no; 1662 return StartOffset; 1663 } 1664 1665 uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, 1666 unsigned GOTRelType) { 1667 auto E = GOTOffsetMap.insert({Value, 0}); 1668 if (E.second) { 1669 uint64_t GOTOffset = allocateGOTEntries(1); 1670 1671 // Create relocation for newly created GOT entry 1672 RelocationEntry RE = 1673 computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); 1674 if (Value.SymbolName) 1675 addRelocationForSymbol(RE, Value.SymbolName); 1676 else 1677 addRelocationForSection(RE, Value.SectionID); 1678 1679 E.first->second = GOTOffset; 1680 } 1681 1682 return E.first->second; 1683 } 1684 1685 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, 1686 uint64_t Offset, 1687 uint64_t GOTOffset, 1688 uint32_t Type) { 1689 // Fill in the relative address of the GOT Entry into the stub 1690 RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); 1691 addRelocationForSection(GOTRE, GOTSectionID); 1692 } 1693 1694 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, 1695 uint64_t SymbolOffset, 1696 uint32_t Type) { 1697 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1698 } 1699 1700 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1701 ObjSectionToIDMap &SectionMap) { 1702 if (IsMipsO32ABI) 1703 if (!PendingRelocs.empty()) 1704 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); 1705 1706 // If necessary, allocate the global offset table 1707 if (GOTSectionID != 0) { 1708 // Allocate memory for the section 1709 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1710 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1711 GOTSectionID, ".got", false); 1712 if (!Addr) 1713 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); 1714 1715 Sections[GOTSectionID] = 1716 SectionEntry(".got", Addr, TotalSize, TotalSize, 0); 1717 1718 if (Checker) 1719 Checker->registerSection(Obj.getFileName(), GOTSectionID); 1720 1721 // For now, initialize all GOT entries to zero. We'll fill them in as 1722 // needed when GOT-based relocations are applied. 1723 memset(Addr, 0, TotalSize); 1724 if (IsMipsN32ABI || IsMipsN64ABI) { 1725 // To correctly resolve Mips GOT relocations, we need a mapping from 1726 // object's sections to GOTs. 1727 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); 1728 SI != SE; ++SI) { 1729 if (SI->relocation_begin() != SI->relocation_end()) { 1730 section_iterator RelocatedSection = SI->getRelocatedSection(); 1731 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); 1732 assert (i != SectionMap.end()); 1733 SectionToGOTMap[i->second] = GOTSectionID; 1734 } 1735 } 1736 GOTSymbolOffsets.clear(); 1737 } 1738 } 1739 1740 // Look for and record the EH frame section. 1741 ObjSectionToIDMap::iterator i, e; 1742 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1743 const SectionRef &Section = i->first; 1744 StringRef Name; 1745 Section.getName(Name); 1746 if (Name == ".eh_frame") { 1747 UnregisteredEHFrameSections.push_back(i->second); 1748 break; 1749 } 1750 } 1751 1752 GOTSectionID = 0; 1753 CurrentGOTIndex = 0; 1754 1755 return Error::success(); 1756 } 1757 1758 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1759 return Obj.isELF(); 1760 } 1761 1762 bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { 1763 unsigned RelTy = R.getType(); 1764 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) 1765 return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || 1766 RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; 1767 1768 if (Arch == Triple::x86_64) 1769 return RelTy == ELF::R_X86_64_GOTPCREL || 1770 RelTy == ELF::R_X86_64_GOTPCRELX || 1771 RelTy == ELF::R_X86_64_REX_GOTPCRELX; 1772 return false; 1773 } 1774 1775 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { 1776 if (Arch != Triple::x86_64) 1777 return true; // Conservative answer 1778 1779 switch (R.getType()) { 1780 default: 1781 return true; // Conservative answer 1782 1783 1784 case ELF::R_X86_64_GOTPCREL: 1785 case ELF::R_X86_64_GOTPCRELX: 1786 case ELF::R_X86_64_REX_GOTPCRELX: 1787 case ELF::R_X86_64_PC32: 1788 case ELF::R_X86_64_PC64: 1789 case ELF::R_X86_64_64: 1790 // We know that these reloation types won't need a stub function. This list 1791 // can be extended as needed. 1792 return false; 1793 } 1794 } 1795 1796 } // namespace llvm 1797