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 "llvm/ADT/IntervalMap.h" 17 #include "llvm/ADT/STLExtras.h" 18 #include "llvm/ADT/StringRef.h" 19 #include "llvm/ADT/Triple.h" 20 #include "llvm/MC/MCStreamer.h" 21 #include "llvm/Object/ELFObjectFile.h" 22 #include "llvm/Object/ObjectFile.h" 23 #include "llvm/Support/ELF.h" 24 #include "llvm/Support/Endian.h" 25 #include "llvm/Support/MemoryBuffer.h" 26 #include "llvm/Support/TargetRegistry.h" 27 28 using namespace llvm; 29 using namespace llvm::object; 30 31 #define DEBUG_TYPE "dyld" 32 33 static inline std::error_code check(std::error_code Err) { 34 if (Err) { 35 report_fatal_error(Err.message()); 36 } 37 return Err; 38 } 39 40 namespace { 41 42 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> { 43 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) 44 45 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr; 46 typedef Elf_Sym_Impl<ELFT> Elf_Sym; 47 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel; 48 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela; 49 50 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; 51 52 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; 53 54 public: 55 DyldELFObject(MemoryBufferRef Wrapper, std::error_code &ec); 56 57 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 58 59 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); 60 61 // Methods for type inquiry through isa, cast and dyn_cast 62 static inline bool classof(const Binary *v) { 63 return (isa<ELFObjectFile<ELFT>>(v) && 64 classof(cast<ELFObjectFile<ELFT>>(v))); 65 } 66 static inline bool classof(const ELFObjectFile<ELFT> *v) { 67 return v->isDyldType(); 68 } 69 70 }; 71 72 73 74 // The MemoryBuffer passed into this constructor is just a wrapper around the 75 // actual memory. Ultimately, the Binary parent class will take ownership of 76 // this MemoryBuffer object but not the underlying memory. 77 template <class ELFT> 78 DyldELFObject<ELFT>::DyldELFObject(MemoryBufferRef Wrapper, std::error_code &EC) 79 : ELFObjectFile<ELFT>(Wrapper, EC) { 80 this->isDyldELFObject = true; 81 } 82 83 template <class ELFT> 84 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 85 uint64_t Addr) { 86 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 87 Elf_Shdr *shdr = 88 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 89 90 // This assumes the address passed in matches the target address bitness 91 // The template-based type cast handles everything else. 92 shdr->sh_addr = static_cast<addr_type>(Addr); 93 } 94 95 template <class ELFT> 96 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 97 uint64_t Addr) { 98 99 Elf_Sym *sym = const_cast<Elf_Sym *>( 100 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 101 102 // This assumes the address passed in matches the target address bitness 103 // The template-based type cast handles everything else. 104 sym->st_value = static_cast<addr_type>(Addr); 105 } 106 107 class LoadedELFObjectInfo : public RuntimeDyld::LoadedObjectInfo { 108 public: 109 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, unsigned BeginIdx, 110 unsigned EndIdx) 111 : RuntimeDyld::LoadedObjectInfo(RTDyld, BeginIdx, EndIdx) {} 112 113 OwningBinary<ObjectFile> 114 getObjectForDebug(const ObjectFile &Obj) const override; 115 }; 116 117 template <typename ELFT> 118 std::unique_ptr<DyldELFObject<ELFT>> 119 createRTDyldELFObject(MemoryBufferRef Buffer, 120 const LoadedELFObjectInfo &L, 121 std::error_code &ec) { 122 typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr; 123 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; 124 125 std::unique_ptr<DyldELFObject<ELFT>> Obj = 126 llvm::make_unique<DyldELFObject<ELFT>>(Buffer, ec); 127 128 // Iterate over all sections in the object. 129 for (const auto &Sec : Obj->sections()) { 130 StringRef SectionName; 131 Sec.getName(SectionName); 132 if (SectionName != "") { 133 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 134 Elf_Shdr *shdr = const_cast<Elf_Shdr *>( 135 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 136 137 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(SectionName)) { 138 // This assumes that the address passed in matches the target address 139 // bitness. The template-based type cast handles everything else. 140 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); 141 } 142 } 143 } 144 145 return Obj; 146 } 147 148 OwningBinary<ObjectFile> createELFDebugObject(const ObjectFile &Obj, 149 const LoadedELFObjectInfo &L) { 150 assert(Obj.isELF() && "Not an ELF object file."); 151 152 std::unique_ptr<MemoryBuffer> Buffer = 153 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); 154 155 std::error_code ec; 156 157 std::unique_ptr<ObjectFile> DebugObj; 158 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) { 159 typedef ELFType<support::little, 2, false> ELF32LE; 160 DebugObj = createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), L, ec); 161 } else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) { 162 typedef ELFType<support::big, 2, false> ELF32BE; 163 DebugObj = createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), L, ec); 164 } else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) { 165 typedef ELFType<support::big, 2, true> ELF64BE; 166 DebugObj = createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), L, ec); 167 } else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) { 168 typedef ELFType<support::little, 2, true> ELF64LE; 169 DebugObj = createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), L, ec); 170 } else 171 llvm_unreachable("Unexpected ELF format"); 172 173 assert(!ec && "Could not construct copy ELF object file"); 174 175 return OwningBinary<ObjectFile>(std::move(DebugObj), std::move(Buffer)); 176 } 177 178 OwningBinary<ObjectFile> 179 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { 180 return createELFDebugObject(Obj, *this); 181 } 182 183 } // namespace 184 185 namespace llvm { 186 187 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, 188 RuntimeDyld::SymbolResolver &Resolver) 189 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} 190 RuntimeDyldELF::~RuntimeDyldELF() {} 191 192 void RuntimeDyldELF::registerEHFrames() { 193 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { 194 SID EHFrameSID = UnregisteredEHFrameSections[i]; 195 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address; 196 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress; 197 size_t EHFrameSize = Sections[EHFrameSID].Size; 198 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 199 RegisteredEHFrameSections.push_back(EHFrameSID); 200 } 201 UnregisteredEHFrameSections.clear(); 202 } 203 204 void RuntimeDyldELF::deregisterEHFrames() { 205 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) { 206 SID EHFrameSID = RegisteredEHFrameSections[i]; 207 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address; 208 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress; 209 size_t EHFrameSize = Sections[EHFrameSID].Size; 210 MemMgr.deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); 211 } 212 RegisteredEHFrameSections.clear(); 213 } 214 215 std::unique_ptr<RuntimeDyld::LoadedObjectInfo> 216 RuntimeDyldELF::loadObject(const object::ObjectFile &O) { 217 unsigned SectionStartIdx, SectionEndIdx; 218 std::tie(SectionStartIdx, SectionEndIdx) = loadObjectImpl(O); 219 return llvm::make_unique<LoadedELFObjectInfo>(*this, SectionStartIdx, 220 SectionEndIdx); 221 } 222 223 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 224 uint64_t Offset, uint64_t Value, 225 uint32_t Type, int64_t Addend, 226 uint64_t SymOffset) { 227 switch (Type) { 228 default: 229 llvm_unreachable("Relocation type not implemented yet!"); 230 break; 231 case ELF::R_X86_64_64: { 232 support::ulittle64_t::ref(Section.Address + Offset) = Value + Addend; 233 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " 234 << format("%p\n", Section.Address + Offset)); 235 break; 236 } 237 case ELF::R_X86_64_32: 238 case ELF::R_X86_64_32S: { 239 Value += Addend; 240 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 241 (Type == ELF::R_X86_64_32S && 242 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 243 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 244 support::ulittle32_t::ref(Section.Address + Offset) = TruncatedAddr; 245 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " 246 << format("%p\n", Section.Address + Offset)); 247 break; 248 } 249 case ELF::R_X86_64_PC32: { 250 // Get the placeholder value from the generated object since 251 // a previous relocation attempt may have overwritten the loaded version 252 support::ulittle32_t::ref Placeholder( 253 (void *)(Section.ObjAddress + Offset)); 254 uint64_t FinalAddress = Section.LoadAddress + Offset; 255 int64_t RealOffset = Value + Addend - FinalAddress; 256 // Don't add the placeholder if this is a stub 257 if (Offset < Section.Size) 258 RealOffset += Placeholder; 259 assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN); 260 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 261 support::ulittle32_t::ref(Section.Address + Offset) = TruncOffset; 262 break; 263 } 264 case ELF::R_X86_64_PC64: { 265 // Get the placeholder value from the generated object since 266 // a previous relocation attempt may have overwritten the loaded version 267 support::ulittle64_t::ref Placeholder( 268 (void *)(Section.ObjAddress + Offset)); 269 uint64_t FinalAddress = Section.LoadAddress + Offset; 270 int64_t RealOffset = Value + Addend - FinalAddress; 271 if (Offset < Section.Size) 272 RealOffset += Placeholder; 273 support::ulittle64_t::ref(Section.Address + Offset) = RealOffset; 274 break; 275 } 276 } 277 } 278 279 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 280 uint64_t Offset, uint32_t Value, 281 uint32_t Type, int32_t Addend) { 282 switch (Type) { 283 case ELF::R_386_32: { 284 // Get the placeholder value from the generated object since 285 // a previous relocation attempt may have overwritten the loaded version 286 support::ulittle32_t::ref Placeholder( 287 (void *)(Section.ObjAddress + Offset)); 288 support::ulittle32_t::ref(Section.Address + Offset) = 289 Placeholder + Value + Addend; 290 break; 291 } 292 case ELF::R_386_PC32: { 293 // Get the placeholder value from the generated object since 294 // a previous relocation attempt may have overwritten the loaded version 295 support::ulittle32_t::ref Placeholder( 296 (void *)(Section.ObjAddress + Offset)); 297 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF); 298 uint32_t RealOffset = Placeholder + Value + Addend - FinalAddress; 299 support::ulittle32_t::ref(Section.Address + Offset) = RealOffset; 300 break; 301 } 302 default: 303 // There are other relocation types, but it appears these are the 304 // only ones currently used by the LLVM ELF object writer 305 llvm_unreachable("Relocation type not implemented yet!"); 306 break; 307 } 308 } 309 310 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 311 uint64_t Offset, uint64_t Value, 312 uint32_t Type, int64_t Addend) { 313 uint32_t *TargetPtr = reinterpret_cast<uint32_t *>(Section.Address + Offset); 314 uint64_t FinalAddress = Section.LoadAddress + Offset; 315 316 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 317 << format("%llx", Section.Address + Offset) 318 << " FinalAddress: 0x" << format("%llx", FinalAddress) 319 << " Value: 0x" << format("%llx", Value) << " Type: 0x" 320 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend) 321 << "\n"); 322 323 switch (Type) { 324 default: 325 llvm_unreachable("Relocation type not implemented yet!"); 326 break; 327 case ELF::R_AARCH64_ABS64: { 328 uint64_t *TargetPtr = 329 reinterpret_cast<uint64_t *>(Section.Address + Offset); 330 *TargetPtr = Value + Addend; 331 break; 332 } 333 case ELF::R_AARCH64_PREL32: { 334 uint64_t Result = Value + Addend - FinalAddress; 335 assert(static_cast<int64_t>(Result) >= INT32_MIN && 336 static_cast<int64_t>(Result) <= UINT32_MAX); 337 *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU); 338 break; 339 } 340 case ELF::R_AARCH64_CALL26: // fallthrough 341 case ELF::R_AARCH64_JUMP26: { 342 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 343 // calculation. 344 uint64_t BranchImm = Value + Addend - FinalAddress; 345 346 // "Check that -2^27 <= result < 2^27". 347 assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) && 348 static_cast<int64_t>(BranchImm) < (1LL << 27)); 349 350 // AArch64 code is emitted with .rela relocations. The data already in any 351 // bits affected by the relocation on entry is garbage. 352 *TargetPtr &= 0xfc000000U; 353 // Immediate goes in bits 25:0 of B and BL. 354 *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2; 355 break; 356 } 357 case ELF::R_AARCH64_MOVW_UABS_G3: { 358 uint64_t Result = Value + Addend; 359 360 // AArch64 code is emitted with .rela relocations. The data already in any 361 // bits affected by the relocation on entry is garbage. 362 *TargetPtr &= 0xffe0001fU; 363 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 364 *TargetPtr |= Result >> (48 - 5); 365 // Shift must be "lsl #48", in bits 22:21 366 assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation"); 367 break; 368 } 369 case ELF::R_AARCH64_MOVW_UABS_G2_NC: { 370 uint64_t Result = Value + Addend; 371 372 // AArch64 code is emitted with .rela relocations. The data already in any 373 // bits affected by the relocation on entry is garbage. 374 *TargetPtr &= 0xffe0001fU; 375 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 376 *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5)); 377 // Shift must be "lsl #32", in bits 22:21 378 assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation"); 379 break; 380 } 381 case ELF::R_AARCH64_MOVW_UABS_G1_NC: { 382 uint64_t Result = Value + Addend; 383 384 // AArch64 code is emitted with .rela relocations. The data already in any 385 // bits affected by the relocation on entry is garbage. 386 *TargetPtr &= 0xffe0001fU; 387 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 388 *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5)); 389 // Shift must be "lsl #16", in bits 22:2 390 assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation"); 391 break; 392 } 393 case ELF::R_AARCH64_MOVW_UABS_G0_NC: { 394 uint64_t Result = Value + Addend; 395 396 // AArch64 code is emitted with .rela relocations. The data already in any 397 // bits affected by the relocation on entry is garbage. 398 *TargetPtr &= 0xffe0001fU; 399 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 400 *TargetPtr |= ((Result & 0xffffU) << 5); 401 // Shift must be "lsl #0", in bits 22:21. 402 assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation"); 403 break; 404 } 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(static_cast<int64_t>(Result) >= (-1LL << 32) && 412 static_cast<int64_t>(Result) < (1LL << 32) && 413 "overflow check failed for relocation"); 414 415 // AArch64 code is emitted with .rela relocations. The data already in any 416 // bits affected by the relocation on entry is garbage. 417 *TargetPtr &= 0x9f00001fU; 418 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken 419 // from bits 32:12 of X. 420 *TargetPtr |= ((Result & 0x3000U) << (29 - 12)); 421 *TargetPtr |= ((Result & 0x1ffffc000ULL) >> (14 - 5)); 422 break; 423 } 424 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: { 425 // Operation: S + A 426 uint64_t Result = Value + Addend; 427 428 // AArch64 code is emitted with .rela relocations. The data already in any 429 // bits affected by the relocation on entry is garbage. 430 *TargetPtr &= 0xffc003ffU; 431 // Immediate goes in bits 21:10 of LD/ST instruction, taken 432 // from bits 11:2 of X 433 *TargetPtr |= ((Result & 0xffc) << (10 - 2)); 434 break; 435 } 436 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: { 437 // Operation: S + A 438 uint64_t Result = Value + Addend; 439 440 // AArch64 code is emitted with .rela relocations. The data already in any 441 // bits affected by the relocation on entry is garbage. 442 *TargetPtr &= 0xffc003ffU; 443 // Immediate goes in bits 21:10 of LD/ST instruction, taken 444 // from bits 11:3 of X 445 *TargetPtr |= ((Result & 0xff8) << (10 - 3)); 446 break; 447 } 448 } 449 } 450 451 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 452 uint64_t Offset, uint32_t Value, 453 uint32_t Type, int32_t Addend) { 454 // TODO: Add Thumb relocations. 455 uint32_t *Placeholder = 456 reinterpret_cast<uint32_t *>(Section.ObjAddress + Offset); 457 uint32_t *TargetPtr = (uint32_t *)(Section.Address + Offset); 458 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF); 459 Value += Addend; 460 461 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 462 << Section.Address + Offset 463 << " FinalAddress: " << format("%p", FinalAddress) << " Value: " 464 << format("%x", Value) << " Type: " << format("%x", Type) 465 << " Addend: " << format("%x", Addend) << "\n"); 466 467 switch (Type) { 468 default: 469 llvm_unreachable("Not implemented relocation type!"); 470 471 case ELF::R_ARM_NONE: 472 break; 473 // Write a 32bit value to relocation address, taking into account the 474 // implicit addend encoded in the target. 475 case ELF::R_ARM_PREL31: 476 case ELF::R_ARM_TARGET1: 477 case ELF::R_ARM_ABS32: 478 *TargetPtr = *Placeholder + Value; 479 break; 480 // Write first 16 bit of 32 bit value to the mov instruction. 481 // Last 4 bit should be shifted. 482 case ELF::R_ARM_MOVW_ABS_NC: 483 // We are not expecting any other addend in the relocation address. 484 // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2 485 // non-contiguous fields. 486 assert((*Placeholder & 0x000F0FFF) == 0); 487 Value = Value & 0xFFFF; 488 *TargetPtr = *Placeholder | (Value & 0xFFF); 489 *TargetPtr |= ((Value >> 12) & 0xF) << 16; 490 break; 491 // Write last 16 bit of 32 bit value to the mov instruction. 492 // Last 4 bit should be shifted. 493 case ELF::R_ARM_MOVT_ABS: 494 // We are not expecting any other addend in the relocation address. 495 // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC. 496 assert((*Placeholder & 0x000F0FFF) == 0); 497 498 Value = (Value >> 16) & 0xFFFF; 499 *TargetPtr = *Placeholder | (Value & 0xFFF); 500 *TargetPtr |= ((Value >> 12) & 0xF) << 16; 501 break; 502 // Write 24 bit relative value to the branch instruction. 503 case ELF::R_ARM_PC24: // Fall through. 504 case ELF::R_ARM_CALL: // Fall through. 505 case ELF::R_ARM_JUMP24: { 506 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 507 RelValue = (RelValue & 0x03FFFFFC) >> 2; 508 assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE); 509 *TargetPtr &= 0xFF000000; 510 *TargetPtr |= RelValue; 511 break; 512 } 513 case ELF::R_ARM_PRIVATE_0: 514 // This relocation is reserved by the ARM ELF ABI for internal use. We 515 // appropriate it here to act as an R_ARM_ABS32 without any addend for use 516 // in the stubs created during JIT (which can't put an addend into the 517 // original object file). 518 *TargetPtr = Value; 519 break; 520 } 521 } 522 523 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section, 524 uint64_t Offset, uint32_t Value, 525 uint32_t Type, int32_t Addend) { 526 uint32_t *Placeholder = 527 reinterpret_cast<uint32_t *>(Section.ObjAddress + Offset); 528 uint32_t *TargetPtr = (uint32_t *)(Section.Address + Offset); 529 Value += Addend; 530 531 DEBUG(dbgs() << "resolveMipselocation, LocalAddress: " 532 << Section.Address + Offset << " FinalAddress: " 533 << format("%p", Section.LoadAddress + Offset) << " Value: " 534 << format("%x", Value) << " Type: " << format("%x", Type) 535 << " Addend: " << format("%x", Addend) << "\n"); 536 537 switch (Type) { 538 default: 539 llvm_unreachable("Not implemented relocation type!"); 540 break; 541 case ELF::R_MIPS_32: 542 *TargetPtr = Value + (*Placeholder); 543 break; 544 case ELF::R_MIPS_26: 545 *TargetPtr = ((*Placeholder) & 0xfc000000) | ((Value & 0x0fffffff) >> 2); 546 break; 547 case ELF::R_MIPS_HI16: 548 // Get the higher 16-bits. Also add 1 if bit 15 is 1. 549 Value += ((*Placeholder) & 0x0000ffff) << 16; 550 *TargetPtr = 551 ((*Placeholder) & 0xffff0000) | (((Value + 0x8000) >> 16) & 0xffff); 552 break; 553 case ELF::R_MIPS_LO16: 554 Value += ((*Placeholder) & 0x0000ffff); 555 *TargetPtr = ((*Placeholder) & 0xffff0000) | (Value & 0xffff); 556 break; 557 case ELF::R_MIPS_UNUSED1: 558 // Similar to ELF::R_ARM_PRIVATE_0, R_MIPS_UNUSED1 and R_MIPS_UNUSED2 559 // are used for internal JIT purpose. These relocations are similar to 560 // R_MIPS_HI16 and R_MIPS_LO16, but they do not take any addend into 561 // account. 562 *TargetPtr = 563 ((*TargetPtr) & 0xffff0000) | (((Value + 0x8000) >> 16) & 0xffff); 564 break; 565 case ELF::R_MIPS_UNUSED2: 566 *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff); 567 break; 568 } 569 } 570 571 // Return the .TOC. section and offset. 572 void RuntimeDyldELF::findPPC64TOCSection(const ObjectFile &Obj, 573 ObjSectionToIDMap &LocalSections, 574 RelocationValueRef &Rel) { 575 // Set a default SectionID in case we do not find a TOC section below. 576 // This may happen for references to TOC base base (sym@toc, .odp 577 // relocation) without a .toc directive. In this case just use the 578 // first section (which is usually the .odp) since the code won't 579 // reference the .toc base directly. 580 Rel.SymbolName = NULL; 581 Rel.SectionID = 0; 582 583 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 584 // order. The TOC starts where the first of these sections starts. 585 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 586 si != se; ++si) { 587 588 StringRef SectionName; 589 check(si->getName(SectionName)); 590 591 if (SectionName == ".got" 592 || SectionName == ".toc" 593 || SectionName == ".tocbss" 594 || SectionName == ".plt") { 595 Rel.SectionID = findOrEmitSection(Obj, *si, false, LocalSections); 596 break; 597 } 598 } 599 600 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 601 // thus permitting a full 64 Kbytes segment. 602 Rel.Addend = 0x8000; 603 } 604 605 // Returns the sections and offset associated with the ODP entry referenced 606 // by Symbol. 607 void RuntimeDyldELF::findOPDEntrySection(const ObjectFile &Obj, 608 ObjSectionToIDMap &LocalSections, 609 RelocationValueRef &Rel) { 610 // Get the ELF symbol value (st_value) to compare with Relocation offset in 611 // .opd entries 612 for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); 613 si != se; ++si) { 614 section_iterator RelSecI = si->getRelocatedSection(); 615 if (RelSecI == Obj.section_end()) 616 continue; 617 618 StringRef RelSectionName; 619 check(RelSecI->getName(RelSectionName)); 620 if (RelSectionName != ".opd") 621 continue; 622 623 for (relocation_iterator i = si->relocation_begin(), 624 e = si->relocation_end(); 625 i != e;) { 626 // The R_PPC64_ADDR64 relocation indicates the first field 627 // of a .opd entry 628 uint64_t TypeFunc; 629 check(i->getType(TypeFunc)); 630 if (TypeFunc != ELF::R_PPC64_ADDR64) { 631 ++i; 632 continue; 633 } 634 635 uint64_t TargetSymbolOffset; 636 symbol_iterator TargetSymbol = i->getSymbol(); 637 check(i->getOffset(TargetSymbolOffset)); 638 int64_t Addend; 639 check(getELFRelocationAddend(*i, Addend)); 640 641 ++i; 642 if (i == e) 643 break; 644 645 // Just check if following relocation is a R_PPC64_TOC 646 uint64_t TypeTOC; 647 check(i->getType(TypeTOC)); 648 if (TypeTOC != ELF::R_PPC64_TOC) 649 continue; 650 651 // Finally compares the Symbol value and the target symbol offset 652 // to check if this .opd entry refers to the symbol the relocation 653 // points to. 654 if (Rel.Addend != (int64_t)TargetSymbolOffset) 655 continue; 656 657 section_iterator tsi(Obj.section_end()); 658 check(TargetSymbol->getSection(tsi)); 659 bool IsCode = tsi->isText(); 660 Rel.SectionID = findOrEmitSection(Obj, (*tsi), IsCode, LocalSections); 661 Rel.Addend = (intptr_t)Addend; 662 return; 663 } 664 } 665 llvm_unreachable("Attempting to get address of ODP entry!"); 666 } 667 668 // Relocation masks following the #lo(value), #hi(value), #ha(value), 669 // #higher(value), #highera(value), #highest(value), and #highesta(value) 670 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 671 // document. 672 673 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } 674 675 static inline uint16_t applyPPChi(uint64_t value) { 676 return (value >> 16) & 0xffff; 677 } 678 679 static inline uint16_t applyPPCha (uint64_t value) { 680 return ((value + 0x8000) >> 16) & 0xffff; 681 } 682 683 static inline uint16_t applyPPChigher(uint64_t value) { 684 return (value >> 32) & 0xffff; 685 } 686 687 static inline uint16_t applyPPChighera (uint64_t value) { 688 return ((value + 0x8000) >> 32) & 0xffff; 689 } 690 691 static inline uint16_t applyPPChighest(uint64_t value) { 692 return (value >> 48) & 0xffff; 693 } 694 695 static inline uint16_t applyPPChighesta (uint64_t value) { 696 return ((value + 0x8000) >> 48) & 0xffff; 697 } 698 699 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 700 uint64_t Offset, uint64_t Value, 701 uint32_t Type, int64_t Addend) { 702 uint8_t *LocalAddress = Section.Address + Offset; 703 switch (Type) { 704 default: 705 llvm_unreachable("Relocation type not implemented yet!"); 706 break; 707 case ELF::R_PPC64_ADDR16: 708 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 709 break; 710 case ELF::R_PPC64_ADDR16_DS: 711 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 712 break; 713 case ELF::R_PPC64_ADDR16_LO: 714 writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); 715 break; 716 case ELF::R_PPC64_ADDR16_LO_DS: 717 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); 718 break; 719 case ELF::R_PPC64_ADDR16_HI: 720 writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); 721 break; 722 case ELF::R_PPC64_ADDR16_HA: 723 writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); 724 break; 725 case ELF::R_PPC64_ADDR16_HIGHER: 726 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); 727 break; 728 case ELF::R_PPC64_ADDR16_HIGHERA: 729 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); 730 break; 731 case ELF::R_PPC64_ADDR16_HIGHEST: 732 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); 733 break; 734 case ELF::R_PPC64_ADDR16_HIGHESTA: 735 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); 736 break; 737 case ELF::R_PPC64_ADDR14: { 738 assert(((Value + Addend) & 3) == 0); 739 // Preserve the AA/LK bits in the branch instruction 740 uint8_t aalk = *(LocalAddress + 3); 741 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 742 } break; 743 case ELF::R_PPC64_REL16_LO: { 744 uint64_t FinalAddress = (Section.LoadAddress + Offset); 745 uint64_t Delta = Value - FinalAddress + Addend; 746 writeInt16BE(LocalAddress, applyPPClo(Delta)); 747 } break; 748 case ELF::R_PPC64_REL16_HI: { 749 uint64_t FinalAddress = (Section.LoadAddress + Offset); 750 uint64_t Delta = Value - FinalAddress + Addend; 751 writeInt16BE(LocalAddress, applyPPChi(Delta)); 752 } break; 753 case ELF::R_PPC64_REL16_HA: { 754 uint64_t FinalAddress = (Section.LoadAddress + Offset); 755 uint64_t Delta = Value - FinalAddress + Addend; 756 writeInt16BE(LocalAddress, applyPPCha(Delta)); 757 } break; 758 case ELF::R_PPC64_ADDR32: { 759 int32_t Result = static_cast<int32_t>(Value + Addend); 760 if (SignExtend32<32>(Result) != Result) 761 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 762 writeInt32BE(LocalAddress, Result); 763 } break; 764 case ELF::R_PPC64_REL24: { 765 uint64_t FinalAddress = (Section.LoadAddress + Offset); 766 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 767 if (SignExtend32<24>(delta) != delta) 768 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 769 // Generates a 'bl <address>' instruction 770 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); 771 } break; 772 case ELF::R_PPC64_REL32: { 773 uint64_t FinalAddress = (Section.LoadAddress + Offset); 774 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 775 if (SignExtend32<32>(delta) != delta) 776 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 777 writeInt32BE(LocalAddress, delta); 778 } break; 779 case ELF::R_PPC64_REL64: { 780 uint64_t FinalAddress = (Section.LoadAddress + Offset); 781 uint64_t Delta = Value - FinalAddress + Addend; 782 writeInt64BE(LocalAddress, Delta); 783 } break; 784 case ELF::R_PPC64_ADDR64: 785 writeInt64BE(LocalAddress, Value + Addend); 786 break; 787 } 788 } 789 790 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 791 uint64_t Offset, uint64_t Value, 792 uint32_t Type, int64_t Addend) { 793 uint8_t *LocalAddress = Section.Address + Offset; 794 switch (Type) { 795 default: 796 llvm_unreachable("Relocation type not implemented yet!"); 797 break; 798 case ELF::R_390_PC16DBL: 799 case ELF::R_390_PLT16DBL: { 800 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); 801 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 802 writeInt16BE(LocalAddress, Delta / 2); 803 break; 804 } 805 case ELF::R_390_PC32DBL: 806 case ELF::R_390_PLT32DBL: { 807 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); 808 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 809 writeInt32BE(LocalAddress, Delta / 2); 810 break; 811 } 812 case ELF::R_390_PC32: { 813 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); 814 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 815 writeInt32BE(LocalAddress, Delta); 816 break; 817 } 818 case ELF::R_390_64: 819 writeInt64BE(LocalAddress, Value + Addend); 820 break; 821 } 822 } 823 824 // The target location for the relocation is described by RE.SectionID and 825 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each 826 // SectionEntry has three members describing its location. 827 // SectionEntry::Address is the address at which the section has been loaded 828 // into memory in the current (host) process. SectionEntry::LoadAddress is the 829 // address that the section will have in the target process. 830 // SectionEntry::ObjAddress is the address of the bits for this section in the 831 // original emitted object image (also in the current address space). 832 // 833 // Relocations will be applied as if the section were loaded at 834 // SectionEntry::LoadAddress, but they will be applied at an address based 835 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to 836 // Target memory contents if they are required for value calculations. 837 // 838 // The Value parameter here is the load address of the symbol for the 839 // relocation to be applied. For relocations which refer to symbols in the 840 // current object Value will be the LoadAddress of the section in which 841 // the symbol resides (RE.Addend provides additional information about the 842 // symbol location). For external symbols, Value will be the address of the 843 // symbol in the target address space. 844 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 845 uint64_t Value) { 846 const SectionEntry &Section = Sections[RE.SectionID]; 847 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, 848 RE.SymOffset); 849 } 850 851 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 852 uint64_t Offset, uint64_t Value, 853 uint32_t Type, int64_t Addend, 854 uint64_t SymOffset) { 855 switch (Arch) { 856 case Triple::x86_64: 857 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); 858 break; 859 case Triple::x86: 860 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 861 (uint32_t)(Addend & 0xffffffffL)); 862 break; 863 case Triple::aarch64: 864 case Triple::aarch64_be: 865 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 866 break; 867 case Triple::arm: // Fall through. 868 case Triple::armeb: 869 case Triple::thumb: 870 case Triple::thumbeb: 871 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, 872 (uint32_t)(Addend & 0xffffffffL)); 873 break; 874 case Triple::mips: // Fall through. 875 case Triple::mipsel: 876 resolveMIPSRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), 877 Type, (uint32_t)(Addend & 0xffffffffL)); 878 break; 879 case Triple::ppc64: // Fall through. 880 case Triple::ppc64le: 881 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 882 break; 883 case Triple::systemz: 884 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 885 break; 886 default: 887 llvm_unreachable("Unsupported CPU type!"); 888 } 889 } 890 891 relocation_iterator RuntimeDyldELF::processRelocationRef( 892 unsigned SectionID, relocation_iterator RelI, 893 const ObjectFile &Obj, 894 ObjSectionToIDMap &ObjSectionToID, 895 StubMap &Stubs) { 896 uint64_t RelType; 897 Check(RelI->getType(RelType)); 898 int64_t Addend; 899 Check(getELFRelocationAddend(*RelI, Addend)); 900 symbol_iterator Symbol = RelI->getSymbol(); 901 902 // Obtain the symbol name which is referenced in the relocation 903 StringRef TargetName; 904 if (Symbol != Obj.symbol_end()) 905 Symbol->getName(TargetName); 906 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend 907 << " TargetName: " << TargetName << "\n"); 908 RelocationValueRef Value; 909 // First search for the symbol in the local symbol table 910 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 911 912 // Search for the symbol in the global symbol table 913 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); 914 if (Symbol != Obj.symbol_end()) { 915 gsi = GlobalSymbolTable.find(TargetName.data()); 916 Symbol->getType(SymType); 917 } 918 if (gsi != GlobalSymbolTable.end()) { 919 const auto &SymInfo = gsi->second; 920 Value.SectionID = SymInfo.getSectionID(); 921 Value.Offset = SymInfo.getOffset(); 922 Value.Addend = SymInfo.getOffset() + Addend; 923 } else { 924 switch (SymType) { 925 case SymbolRef::ST_Debug: { 926 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 927 // and can be changed by another developers. Maybe best way is add 928 // a new symbol type ST_Section to SymbolRef and use it. 929 section_iterator si(Obj.section_end()); 930 Symbol->getSection(si); 931 if (si == Obj.section_end()) 932 llvm_unreachable("Symbol section not found, bad object file format!"); 933 DEBUG(dbgs() << "\t\tThis is section symbol\n"); 934 bool isCode = si->isText(); 935 Value.SectionID = findOrEmitSection(Obj, (*si), isCode, ObjSectionToID); 936 Value.Addend = Addend; 937 break; 938 } 939 case SymbolRef::ST_Data: 940 case SymbolRef::ST_Unknown: { 941 Value.SymbolName = TargetName.data(); 942 Value.Addend = Addend; 943 944 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which 945 // will manifest here as a NULL symbol name. 946 // We can set this as a valid (but empty) symbol name, and rely 947 // on addRelocationForSymbol to handle this. 948 if (!Value.SymbolName) 949 Value.SymbolName = ""; 950 break; 951 } 952 default: 953 llvm_unreachable("Unresolved symbol type!"); 954 break; 955 } 956 } 957 958 uint64_t Offset; 959 Check(RelI->getOffset(Offset)); 960 961 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset 962 << "\n"); 963 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be) && 964 (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26)) { 965 // This is an AArch64 branch relocation, need to use a stub function. 966 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 967 SectionEntry &Section = Sections[SectionID]; 968 969 // Look for an existing stub. 970 StubMap::const_iterator i = Stubs.find(Value); 971 if (i != Stubs.end()) { 972 resolveRelocation(Section, Offset, (uint64_t)Section.Address + i->second, 973 RelType, 0); 974 DEBUG(dbgs() << " Stub function found\n"); 975 } else { 976 // Create a new stub function. 977 DEBUG(dbgs() << " Create a new stub function\n"); 978 Stubs[Value] = Section.StubOffset; 979 uint8_t *StubTargetAddr = 980 createStubFunction(Section.Address + Section.StubOffset); 981 982 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.Address, 983 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 984 RelocationEntry REmovk_g2(SectionID, StubTargetAddr - Section.Address + 4, 985 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 986 RelocationEntry REmovk_g1(SectionID, StubTargetAddr - Section.Address + 8, 987 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 988 RelocationEntry REmovk_g0(SectionID, 989 StubTargetAddr - Section.Address + 12, 990 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 991 992 if (Value.SymbolName) { 993 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 994 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 995 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 996 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 997 } else { 998 addRelocationForSection(REmovz_g3, Value.SectionID); 999 addRelocationForSection(REmovk_g2, Value.SectionID); 1000 addRelocationForSection(REmovk_g1, Value.SectionID); 1001 addRelocationForSection(REmovk_g0, Value.SectionID); 1002 } 1003 resolveRelocation(Section, Offset, 1004 (uint64_t)Section.Address + Section.StubOffset, RelType, 1005 0); 1006 Section.StubOffset += getMaxStubSize(); 1007 } 1008 } else if (Arch == Triple::arm && 1009 (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || 1010 RelType == ELF::R_ARM_JUMP24)) { 1011 // This is an ARM branch relocation, need to use a stub function. 1012 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation."); 1013 SectionEntry &Section = Sections[SectionID]; 1014 1015 // Look for an existing stub. 1016 StubMap::const_iterator i = Stubs.find(Value); 1017 if (i != Stubs.end()) { 1018 resolveRelocation(Section, Offset, (uint64_t)Section.Address + i->second, 1019 RelType, 0); 1020 DEBUG(dbgs() << " Stub function found\n"); 1021 } else { 1022 // Create a new stub function. 1023 DEBUG(dbgs() << " Create a new stub function\n"); 1024 Stubs[Value] = Section.StubOffset; 1025 uint8_t *StubTargetAddr = 1026 createStubFunction(Section.Address + Section.StubOffset); 1027 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, 1028 ELF::R_ARM_PRIVATE_0, Value.Addend); 1029 if (Value.SymbolName) 1030 addRelocationForSymbol(RE, Value.SymbolName); 1031 else 1032 addRelocationForSection(RE, Value.SectionID); 1033 1034 resolveRelocation(Section, Offset, 1035 (uint64_t)Section.Address + Section.StubOffset, RelType, 1036 0); 1037 Section.StubOffset += getMaxStubSize(); 1038 } 1039 } else if ((Arch == Triple::mipsel || Arch == Triple::mips) && 1040 RelType == ELF::R_MIPS_26) { 1041 // This is an Mips branch relocation, need to use a stub function. 1042 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 1043 SectionEntry &Section = Sections[SectionID]; 1044 uint8_t *Target = Section.Address + Offset; 1045 uint32_t *TargetAddress = (uint32_t *)Target; 1046 1047 // Extract the addend from the instruction. 1048 uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2; 1049 1050 Value.Addend += Addend; 1051 1052 // Look up for existing stub. 1053 StubMap::const_iterator i = Stubs.find(Value); 1054 if (i != Stubs.end()) { 1055 RelocationEntry RE(SectionID, Offset, RelType, i->second); 1056 addRelocationForSection(RE, SectionID); 1057 DEBUG(dbgs() << " Stub function found\n"); 1058 } else { 1059 // Create a new stub function. 1060 DEBUG(dbgs() << " Create a new stub function\n"); 1061 Stubs[Value] = Section.StubOffset; 1062 uint8_t *StubTargetAddr = 1063 createStubFunction(Section.Address + Section.StubOffset); 1064 1065 // Creating Hi and Lo relocations for the filled stub instructions. 1066 RelocationEntry REHi(SectionID, StubTargetAddr - Section.Address, 1067 ELF::R_MIPS_UNUSED1, Value.Addend); 1068 RelocationEntry RELo(SectionID, StubTargetAddr - Section.Address + 4, 1069 ELF::R_MIPS_UNUSED2, Value.Addend); 1070 1071 if (Value.SymbolName) { 1072 addRelocationForSymbol(REHi, Value.SymbolName); 1073 addRelocationForSymbol(RELo, Value.SymbolName); 1074 } else { 1075 addRelocationForSection(REHi, Value.SectionID); 1076 addRelocationForSection(RELo, Value.SectionID); 1077 } 1078 1079 RelocationEntry RE(SectionID, Offset, RelType, Section.StubOffset); 1080 addRelocationForSection(RE, SectionID); 1081 Section.StubOffset += getMaxStubSize(); 1082 } 1083 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { 1084 if (RelType == ELF::R_PPC64_REL24) { 1085 // Determine ABI variant in use for this object. 1086 unsigned AbiVariant; 1087 Obj.getPlatformFlags(AbiVariant); 1088 AbiVariant &= ELF::EF_PPC64_ABI; 1089 // A PPC branch relocation will need a stub function if the target is 1090 // an external symbol (Symbol::ST_Unknown) or if the target address 1091 // is not within the signed 24-bits branch address. 1092 SectionEntry &Section = Sections[SectionID]; 1093 uint8_t *Target = Section.Address + Offset; 1094 bool RangeOverflow = false; 1095 if (SymType != SymbolRef::ST_Unknown) { 1096 if (AbiVariant != 2) { 1097 // In the ELFv1 ABI, a function call may point to the .opd entry, 1098 // so the final symbol value is calculated based on the relocation 1099 // values in the .opd section. 1100 findOPDEntrySection(Obj, ObjSectionToID, Value); 1101 } else { 1102 // In the ELFv2 ABI, a function symbol may provide a local entry 1103 // point, which must be used for direct calls. 1104 uint8_t SymOther; 1105 Symbol->getOther(SymOther); 1106 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); 1107 } 1108 uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend; 1109 int32_t delta = static_cast<int32_t>(Target - RelocTarget); 1110 // If it is within 24-bits branch range, just set the branch target 1111 if (SignExtend32<24>(delta) == delta) { 1112 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1113 if (Value.SymbolName) 1114 addRelocationForSymbol(RE, Value.SymbolName); 1115 else 1116 addRelocationForSection(RE, Value.SectionID); 1117 } else { 1118 RangeOverflow = true; 1119 } 1120 } 1121 if (SymType == SymbolRef::ST_Unknown || RangeOverflow) { 1122 // It is an external symbol (SymbolRef::ST_Unknown) or within a range 1123 // larger than 24-bits. 1124 StubMap::const_iterator i = Stubs.find(Value); 1125 if (i != Stubs.end()) { 1126 // Symbol function stub already created, just relocate to it 1127 resolveRelocation(Section, Offset, 1128 (uint64_t)Section.Address + i->second, RelType, 0); 1129 DEBUG(dbgs() << " Stub function found\n"); 1130 } else { 1131 // Create a new stub function. 1132 DEBUG(dbgs() << " Create a new stub function\n"); 1133 Stubs[Value] = Section.StubOffset; 1134 uint8_t *StubTargetAddr = 1135 createStubFunction(Section.Address + Section.StubOffset, 1136 AbiVariant); 1137 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, 1138 ELF::R_PPC64_ADDR64, Value.Addend); 1139 1140 // Generates the 64-bits address loads as exemplified in section 1141 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to 1142 // apply to the low part of the instructions, so we have to update 1143 // the offset according to the target endianness. 1144 uint64_t StubRelocOffset = StubTargetAddr - Section.Address; 1145 if (!IsTargetLittleEndian) 1146 StubRelocOffset += 2; 1147 1148 RelocationEntry REhst(SectionID, StubRelocOffset + 0, 1149 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1150 RelocationEntry REhr(SectionID, StubRelocOffset + 4, 1151 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1152 RelocationEntry REh(SectionID, StubRelocOffset + 12, 1153 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1154 RelocationEntry REl(SectionID, StubRelocOffset + 16, 1155 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1156 1157 if (Value.SymbolName) { 1158 addRelocationForSymbol(REhst, Value.SymbolName); 1159 addRelocationForSymbol(REhr, Value.SymbolName); 1160 addRelocationForSymbol(REh, Value.SymbolName); 1161 addRelocationForSymbol(REl, Value.SymbolName); 1162 } else { 1163 addRelocationForSection(REhst, Value.SectionID); 1164 addRelocationForSection(REhr, Value.SectionID); 1165 addRelocationForSection(REh, Value.SectionID); 1166 addRelocationForSection(REl, Value.SectionID); 1167 } 1168 1169 resolveRelocation(Section, Offset, 1170 (uint64_t)Section.Address + Section.StubOffset, 1171 RelType, 0); 1172 Section.StubOffset += getMaxStubSize(); 1173 } 1174 if (SymType == SymbolRef::ST_Unknown) { 1175 // Restore the TOC for external calls 1176 if (AbiVariant == 2) 1177 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1) 1178 else 1179 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) 1180 } 1181 } 1182 } else if (RelType == ELF::R_PPC64_TOC16 || 1183 RelType == ELF::R_PPC64_TOC16_DS || 1184 RelType == ELF::R_PPC64_TOC16_LO || 1185 RelType == ELF::R_PPC64_TOC16_LO_DS || 1186 RelType == ELF::R_PPC64_TOC16_HI || 1187 RelType == ELF::R_PPC64_TOC16_HA) { 1188 // These relocations are supposed to subtract the TOC address from 1189 // the final value. This does not fit cleanly into the RuntimeDyld 1190 // scheme, since there may be *two* sections involved in determining 1191 // the relocation value (the section of the symbol refered to by the 1192 // relocation, and the TOC section associated with the current module). 1193 // 1194 // Fortunately, these relocations are currently only ever generated 1195 // refering to symbols that themselves reside in the TOC, which means 1196 // that the two sections are actually the same. Thus they cancel out 1197 // and we can immediately resolve the relocation right now. 1198 switch (RelType) { 1199 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; 1200 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; 1201 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; 1202 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; 1203 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; 1204 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; 1205 default: llvm_unreachable("Wrong relocation type."); 1206 } 1207 1208 RelocationValueRef TOCValue; 1209 findPPC64TOCSection(Obj, ObjSectionToID, TOCValue); 1210 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) 1211 llvm_unreachable("Unsupported TOC relocation."); 1212 Value.Addend -= TOCValue.Addend; 1213 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); 1214 } else { 1215 // There are two ways to refer to the TOC address directly: either 1216 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are 1217 // ignored), or via any relocation that refers to the magic ".TOC." 1218 // symbols (in which case the addend is respected). 1219 if (RelType == ELF::R_PPC64_TOC) { 1220 RelType = ELF::R_PPC64_ADDR64; 1221 findPPC64TOCSection(Obj, ObjSectionToID, Value); 1222 } else if (TargetName == ".TOC.") { 1223 findPPC64TOCSection(Obj, ObjSectionToID, Value); 1224 Value.Addend += Addend; 1225 } 1226 1227 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1228 1229 if (Value.SymbolName) 1230 addRelocationForSymbol(RE, Value.SymbolName); 1231 else 1232 addRelocationForSection(RE, Value.SectionID); 1233 } 1234 } else if (Arch == Triple::systemz && 1235 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { 1236 // Create function stubs for both PLT and GOT references, regardless of 1237 // whether the GOT reference is to data or code. The stub contains the 1238 // full address of the symbol, as needed by GOT references, and the 1239 // executable part only adds an overhead of 8 bytes. 1240 // 1241 // We could try to conserve space by allocating the code and data 1242 // parts of the stub separately. However, as things stand, we allocate 1243 // a stub for every relocation, so using a GOT in JIT code should be 1244 // no less space efficient than using an explicit constant pool. 1245 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1246 SectionEntry &Section = Sections[SectionID]; 1247 1248 // Look for an existing stub. 1249 StubMap::const_iterator i = Stubs.find(Value); 1250 uintptr_t StubAddress; 1251 if (i != Stubs.end()) { 1252 StubAddress = uintptr_t(Section.Address) + i->second; 1253 DEBUG(dbgs() << " Stub function found\n"); 1254 } else { 1255 // Create a new stub function. 1256 DEBUG(dbgs() << " Create a new stub function\n"); 1257 1258 uintptr_t BaseAddress = uintptr_t(Section.Address); 1259 uintptr_t StubAlignment = getStubAlignment(); 1260 StubAddress = (BaseAddress + Section.StubOffset + StubAlignment - 1) & 1261 -StubAlignment; 1262 unsigned StubOffset = StubAddress - BaseAddress; 1263 1264 Stubs[Value] = StubOffset; 1265 createStubFunction((uint8_t *)StubAddress); 1266 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, 1267 Value.Offset); 1268 if (Value.SymbolName) 1269 addRelocationForSymbol(RE, Value.SymbolName); 1270 else 1271 addRelocationForSection(RE, Value.SectionID); 1272 Section.StubOffset = StubOffset + getMaxStubSize(); 1273 } 1274 1275 if (RelType == ELF::R_390_GOTENT) 1276 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, 1277 Addend); 1278 else 1279 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1280 } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_PLT32) { 1281 // The way the PLT relocations normally work is that the linker allocates 1282 // the 1283 // PLT and this relocation makes a PC-relative call into the PLT. The PLT 1284 // entry will then jump to an address provided by the GOT. On first call, 1285 // the 1286 // GOT address will point back into PLT code that resolves the symbol. After 1287 // the first call, the GOT entry points to the actual function. 1288 // 1289 // For local functions we're ignoring all of that here and just replacing 1290 // the PLT32 relocation type with PC32, which will translate the relocation 1291 // into a PC-relative call directly to the function. For external symbols we 1292 // can't be sure the function will be within 2^32 bytes of the call site, so 1293 // we need to create a stub, which calls into the GOT. This case is 1294 // equivalent to the usual PLT implementation except that we use the stub 1295 // mechanism in RuntimeDyld (which puts stubs at the end of the section) 1296 // rather than allocating a PLT section. 1297 if (Value.SymbolName) { 1298 // This is a call to an external function. 1299 // Look for an existing stub. 1300 SectionEntry &Section = Sections[SectionID]; 1301 StubMap::const_iterator i = Stubs.find(Value); 1302 uintptr_t StubAddress; 1303 if (i != Stubs.end()) { 1304 StubAddress = uintptr_t(Section.Address) + i->second; 1305 DEBUG(dbgs() << " Stub function found\n"); 1306 } else { 1307 // Create a new stub function (equivalent to a PLT entry). 1308 DEBUG(dbgs() << " Create a new stub function\n"); 1309 1310 uintptr_t BaseAddress = uintptr_t(Section.Address); 1311 uintptr_t StubAlignment = getStubAlignment(); 1312 StubAddress = (BaseAddress + Section.StubOffset + StubAlignment - 1) & 1313 -StubAlignment; 1314 unsigned StubOffset = StubAddress - BaseAddress; 1315 Stubs[Value] = StubOffset; 1316 createStubFunction((uint8_t *)StubAddress); 1317 1318 // Bump our stub offset counter 1319 Section.StubOffset = StubOffset + getMaxStubSize(); 1320 1321 // Allocate a GOT Entry 1322 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1); 1323 1324 // The load of the GOT address has an addend of -4 1325 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4); 1326 1327 // Fill in the value of the symbol we're targeting into the GOT 1328 addRelocationForSymbol(computeGOTOffsetRE(SectionID,GOTOffset,0,ELF::R_X86_64_64), 1329 Value.SymbolName); 1330 } 1331 1332 // Make the target call a call into the stub table. 1333 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, 1334 Addend); 1335 } else { 1336 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, 1337 Value.Offset); 1338 addRelocationForSection(RE, Value.SectionID); 1339 } 1340 } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) { 1341 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1); 1342 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend); 1343 1344 // Fill in the value of the symbol we're targeting into the GOT 1345 RelocationEntry RE = computeGOTOffsetRE(SectionID, GOTOffset, Value.Offset, ELF::R_X86_64_64); 1346 if (Value.SymbolName) 1347 addRelocationForSymbol(RE, Value.SymbolName); 1348 else 1349 addRelocationForSection(RE, Value.SectionID); 1350 } else { 1351 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); 1352 if (Value.SymbolName) 1353 addRelocationForSymbol(RE, Value.SymbolName); 1354 else 1355 addRelocationForSection(RE, Value.SectionID); 1356 } 1357 return ++RelI; 1358 } 1359 1360 size_t RuntimeDyldELF::getGOTEntrySize() { 1361 // We don't use the GOT in all of these cases, but it's essentially free 1362 // to put them all here. 1363 size_t Result = 0; 1364 switch (Arch) { 1365 case Triple::x86_64: 1366 case Triple::aarch64: 1367 case Triple::aarch64_be: 1368 case Triple::ppc64: 1369 case Triple::ppc64le: 1370 case Triple::systemz: 1371 Result = sizeof(uint64_t); 1372 break; 1373 case Triple::x86: 1374 case Triple::arm: 1375 case Triple::thumb: 1376 case Triple::mips: 1377 case Triple::mipsel: 1378 Result = sizeof(uint32_t); 1379 break; 1380 default: 1381 llvm_unreachable("Unsupported CPU type!"); 1382 } 1383 return Result; 1384 } 1385 1386 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned SectionID, unsigned no) 1387 { 1388 (void)SectionID; // The GOT Section is the same for all section in the object file 1389 if (GOTSectionID == 0) { 1390 GOTSectionID = Sections.size(); 1391 // Reserve a section id. We'll allocate the section later 1392 // once we know the total size 1393 Sections.push_back(SectionEntry(".got", 0, 0, 0)); 1394 } 1395 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); 1396 CurrentGOTIndex += no; 1397 return StartOffset; 1398 } 1399 1400 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, uint64_t GOTOffset) 1401 { 1402 // Fill in the relative address of the GOT Entry into the stub 1403 RelocationEntry GOTRE(SectionID, Offset, ELF::R_X86_64_PC32, GOTOffset); 1404 addRelocationForSection(GOTRE, GOTSectionID); 1405 } 1406 1407 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(unsigned SectionID, uint64_t GOTOffset, uint64_t SymbolOffset, 1408 uint32_t Type) 1409 { 1410 (void)SectionID; // The GOT Section is the same for all section in the object file 1411 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); 1412 } 1413 1414 void RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, 1415 ObjSectionToIDMap &SectionMap) { 1416 // If necessary, allocate the global offset table 1417 if (GOTSectionID != 0) { 1418 // Allocate memory for the section 1419 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); 1420 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), 1421 GOTSectionID, ".got", false); 1422 if (!Addr) 1423 report_fatal_error("Unable to allocate memory for GOT!"); 1424 1425 Sections[GOTSectionID] = SectionEntry(".got", Addr, TotalSize, 0); 1426 1427 if (Checker) 1428 Checker->registerSection(Obj.getFileName(), GOTSectionID); 1429 1430 // For now, initialize all GOT entries to zero. We'll fill them in as 1431 // needed when GOT-based relocations are applied. 1432 memset(Addr, 0, TotalSize); 1433 } 1434 1435 // Look for and record the EH frame section. 1436 ObjSectionToIDMap::iterator i, e; 1437 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { 1438 const SectionRef &Section = i->first; 1439 StringRef Name; 1440 Section.getName(Name); 1441 if (Name == ".eh_frame") { 1442 UnregisteredEHFrameSections.push_back(i->second); 1443 break; 1444 } 1445 } 1446 1447 GOTSectionID = 0; 1448 CurrentGOTIndex = 0; 1449 } 1450 1451 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { 1452 return Obj.isELF(); 1453 } 1454 1455 } // namespace llvm 1456
