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 #define DEBUG_TYPE "dyld" 15 #include "RuntimeDyldELF.h" 16 #include "JITRegistrar.h" 17 #include "ObjectImageCommon.h" 18 #include "llvm/ADT/IntervalMap.h" 19 #include "llvm/ADT/OwningPtr.h" 20 #include "llvm/ADT/STLExtras.h" 21 #include "llvm/ADT/StringRef.h" 22 #include "llvm/ADT/Triple.h" 23 #include "llvm/ExecutionEngine/ObjectBuffer.h" 24 #include "llvm/ExecutionEngine/ObjectImage.h" 25 #include "llvm/Object/ELF.h" 26 #include "llvm/Object/ObjectFile.h" 27 #include "llvm/Support/ELF.h" 28 using namespace llvm; 29 using namespace llvm::object; 30 31 namespace { 32 33 static inline 34 error_code check(error_code Err) { 35 if (Err) { 36 report_fatal_error(Err.message()); 37 } 38 return Err; 39 } 40 41 template<class ELFT> 42 class DyldELFObject 43 : public ELFObjectFile<ELFT> { 44 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) 45 46 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr; 47 typedef Elf_Sym_Impl<ELFT> Elf_Sym; 48 typedef 49 Elf_Rel_Impl<ELFT, false> Elf_Rel; 50 typedef 51 Elf_Rel_Impl<ELFT, true> Elf_Rela; 52 53 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; 54 55 typedef typename ELFDataTypeTypedefHelper< 56 ELFT>::value_type addr_type; 57 58 public: 59 DyldELFObject(MemoryBuffer *Wrapper, error_code &ec); 60 61 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); 62 void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr); 63 64 // Methods for type inquiry through isa, cast and dyn_cast 65 static inline bool classof(const Binary *v) { 66 return (isa<ELFObjectFile<ELFT> >(v) 67 && classof(cast<ELFObjectFile 68 <ELFT> >(v))); 69 } 70 static inline bool classof( 71 const ELFObjectFile<ELFT> *v) { 72 return v->isDyldType(); 73 } 74 }; 75 76 template<class ELFT> 77 class ELFObjectImage : public ObjectImageCommon { 78 protected: 79 DyldELFObject<ELFT> *DyldObj; 80 bool Registered; 81 82 public: 83 ELFObjectImage(ObjectBuffer *Input, 84 DyldELFObject<ELFT> *Obj) 85 : ObjectImageCommon(Input, Obj), 86 DyldObj(Obj), 87 Registered(false) {} 88 89 virtual ~ELFObjectImage() { 90 if (Registered) 91 deregisterWithDebugger(); 92 } 93 94 // Subclasses can override these methods to update the image with loaded 95 // addresses for sections and common symbols 96 virtual void updateSectionAddress(const SectionRef &Sec, uint64_t Addr) 97 { 98 DyldObj->updateSectionAddress(Sec, Addr); 99 } 100 101 virtual void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr) 102 { 103 DyldObj->updateSymbolAddress(Sym, Addr); 104 } 105 106 virtual void registerWithDebugger() 107 { 108 JITRegistrar::getGDBRegistrar().registerObject(*Buffer); 109 Registered = true; 110 } 111 virtual void deregisterWithDebugger() 112 { 113 JITRegistrar::getGDBRegistrar().deregisterObject(*Buffer); 114 } 115 }; 116 117 // The MemoryBuffer passed into this constructor is just a wrapper around the 118 // actual memory. Ultimately, the Binary parent class will take ownership of 119 // this MemoryBuffer object but not the underlying memory. 120 template<class ELFT> 121 DyldELFObject<ELFT>::DyldELFObject(MemoryBuffer *Wrapper, error_code &ec) 122 : ELFObjectFile<ELFT>(Wrapper, ec) { 123 this->isDyldELFObject = true; 124 } 125 126 template<class ELFT> 127 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, 128 uint64_t Addr) { 129 DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); 130 Elf_Shdr *shdr = const_cast<Elf_Shdr*>( 131 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); 132 133 // This assumes the address passed in matches the target address bitness 134 // The template-based type cast handles everything else. 135 shdr->sh_addr = static_cast<addr_type>(Addr); 136 } 137 138 template<class ELFT> 139 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, 140 uint64_t Addr) { 141 142 Elf_Sym *sym = const_cast<Elf_Sym*>( 143 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); 144 145 // This assumes the address passed in matches the target address bitness 146 // The template-based type cast handles everything else. 147 sym->st_value = static_cast<addr_type>(Addr); 148 } 149 150 } // namespace 151 152 namespace llvm { 153 154 StringRef RuntimeDyldELF::getEHFrameSection() { 155 for (int i = 0, e = Sections.size(); i != e; ++i) { 156 if (Sections[i].Name == ".eh_frame") 157 return StringRef((const char*)Sections[i].Address, Sections[i].Size); 158 } 159 return StringRef(); 160 } 161 162 ObjectImage *RuntimeDyldELF::createObjectImage(ObjectBuffer *Buffer) { 163 if (Buffer->getBufferSize() < ELF::EI_NIDENT) 164 llvm_unreachable("Unexpected ELF object size"); 165 std::pair<unsigned char, unsigned char> Ident = std::make_pair( 166 (uint8_t)Buffer->getBufferStart()[ELF::EI_CLASS], 167 (uint8_t)Buffer->getBufferStart()[ELF::EI_DATA]); 168 error_code ec; 169 170 if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) { 171 DyldELFObject<ELFType<support::little, 4, false> > *Obj = 172 new DyldELFObject<ELFType<support::little, 4, false> >( 173 Buffer->getMemBuffer(), ec); 174 return new ELFObjectImage<ELFType<support::little, 4, false> >(Buffer, Obj); 175 } 176 else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB) { 177 DyldELFObject<ELFType<support::big, 4, false> > *Obj = 178 new DyldELFObject<ELFType<support::big, 4, false> >( 179 Buffer->getMemBuffer(), ec); 180 return new ELFObjectImage<ELFType<support::big, 4, false> >(Buffer, Obj); 181 } 182 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB) { 183 DyldELFObject<ELFType<support::big, 8, true> > *Obj = 184 new DyldELFObject<ELFType<support::big, 8, true> >( 185 Buffer->getMemBuffer(), ec); 186 return new ELFObjectImage<ELFType<support::big, 8, true> >(Buffer, Obj); 187 } 188 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) { 189 DyldELFObject<ELFType<support::little, 8, true> > *Obj = 190 new DyldELFObject<ELFType<support::little, 8, true> >( 191 Buffer->getMemBuffer(), ec); 192 return new ELFObjectImage<ELFType<support::little, 8, true> >(Buffer, Obj); 193 } 194 else 195 llvm_unreachable("Unexpected ELF format"); 196 } 197 198 RuntimeDyldELF::~RuntimeDyldELF() { 199 } 200 201 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, 202 uint64_t Offset, 203 uint64_t Value, 204 uint32_t Type, 205 int64_t Addend) { 206 switch (Type) { 207 default: 208 llvm_unreachable("Relocation type not implemented yet!"); 209 break; 210 case ELF::R_X86_64_64: { 211 uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset); 212 *Target = Value + Addend; 213 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) 214 << " at " << format("%p\n",Target)); 215 break; 216 } 217 case ELF::R_X86_64_32: 218 case ELF::R_X86_64_32S: { 219 Value += Addend; 220 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || 221 (Type == ELF::R_X86_64_32S && 222 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); 223 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); 224 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); 225 *Target = TruncatedAddr; 226 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) 227 << " at " << format("%p\n",Target)); 228 break; 229 } 230 case ELF::R_X86_64_PC32: { 231 // Get the placeholder value from the generated object since 232 // a previous relocation attempt may have overwritten the loaded version 233 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress 234 + Offset); 235 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); 236 uint64_t FinalAddress = Section.LoadAddress + Offset; 237 int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress; 238 assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN); 239 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); 240 *Target = TruncOffset; 241 break; 242 } 243 } 244 } 245 246 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, 247 uint64_t Offset, 248 uint32_t Value, 249 uint32_t Type, 250 int32_t Addend) { 251 switch (Type) { 252 case ELF::R_386_32: { 253 // Get the placeholder value from the generated object since 254 // a previous relocation attempt may have overwritten the loaded version 255 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress 256 + Offset); 257 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); 258 *Target = *Placeholder + Value + Addend; 259 break; 260 } 261 case ELF::R_386_PC32: { 262 // Get the placeholder value from the generated object since 263 // a previous relocation attempt may have overwritten the loaded version 264 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress 265 + Offset); 266 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); 267 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF); 268 uint32_t RealOffset = *Placeholder + Value + Addend - FinalAddress; 269 *Target = RealOffset; 270 break; 271 } 272 default: 273 // There are other relocation types, but it appears these are the 274 // only ones currently used by the LLVM ELF object writer 275 llvm_unreachable("Relocation type not implemented yet!"); 276 break; 277 } 278 } 279 280 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, 281 uint64_t Offset, 282 uint64_t Value, 283 uint32_t Type, 284 int64_t Addend) { 285 uint32_t *TargetPtr = reinterpret_cast<uint32_t*>(Section.Address + Offset); 286 uint64_t FinalAddress = Section.LoadAddress + Offset; 287 288 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" 289 << format("%llx", Section.Address + Offset) 290 << " FinalAddress: 0x" << format("%llx",FinalAddress) 291 << " Value: 0x" << format("%llx",Value) 292 << " Type: 0x" << format("%x",Type) 293 << " Addend: 0x" << format("%llx",Addend) 294 << "\n"); 295 296 switch (Type) { 297 default: 298 llvm_unreachable("Relocation type not implemented yet!"); 299 break; 300 case ELF::R_AARCH64_ABS64: { 301 uint64_t *TargetPtr = reinterpret_cast<uint64_t*>(Section.Address + Offset); 302 *TargetPtr = Value + Addend; 303 break; 304 } 305 case ELF::R_AARCH64_PREL32: { 306 uint64_t Result = Value + Addend - FinalAddress; 307 assert(static_cast<int64_t>(Result) >= INT32_MIN && 308 static_cast<int64_t>(Result) <= UINT32_MAX); 309 *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU); 310 break; 311 } 312 case ELF::R_AARCH64_CALL26: // fallthrough 313 case ELF::R_AARCH64_JUMP26: { 314 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the 315 // calculation. 316 uint64_t BranchImm = Value + Addend - FinalAddress; 317 318 // "Check that -2^27 <= result < 2^27". 319 assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) && 320 static_cast<int64_t>(BranchImm) < (1LL << 27)); 321 322 // AArch64 code is emitted with .rela relocations. The data already in any 323 // bits affected by the relocation on entry is garbage. 324 *TargetPtr &= 0xfc000000U; 325 // Immediate goes in bits 25:0 of B and BL. 326 *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2; 327 break; 328 } 329 case ELF::R_AARCH64_MOVW_UABS_G3: { 330 uint64_t Result = Value + Addend; 331 332 // AArch64 code is emitted with .rela relocations. The data already in any 333 // bits affected by the relocation on entry is garbage. 334 *TargetPtr &= 0xff80001fU; 335 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 336 *TargetPtr |= Result >> (48 - 5); 337 // Shift is "lsl #48", in bits 22:21 338 *TargetPtr |= 3 << 21; 339 break; 340 } 341 case ELF::R_AARCH64_MOVW_UABS_G2_NC: { 342 uint64_t Result = Value + Addend; 343 344 345 // AArch64 code is emitted with .rela relocations. The data already in any 346 // bits affected by the relocation on entry is garbage. 347 *TargetPtr &= 0xff80001fU; 348 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 349 *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5)); 350 // Shift is "lsl #32", in bits 22:21 351 *TargetPtr |= 2 << 21; 352 break; 353 } 354 case ELF::R_AARCH64_MOVW_UABS_G1_NC: { 355 uint64_t Result = Value + Addend; 356 357 // AArch64 code is emitted with .rela relocations. The data already in any 358 // bits affected by the relocation on entry is garbage. 359 *TargetPtr &= 0xff80001fU; 360 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 361 *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5)); 362 // Shift is "lsl #16", in bits 22:21 363 *TargetPtr |= 1 << 21; 364 break; 365 } 366 case ELF::R_AARCH64_MOVW_UABS_G0_NC: { 367 uint64_t Result = Value + Addend; 368 369 // AArch64 code is emitted with .rela relocations. The data already in any 370 // bits affected by the relocation on entry is garbage. 371 *TargetPtr &= 0xff80001fU; 372 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction 373 *TargetPtr |= ((Result & 0xffffU) << 5); 374 // Shift is "lsl #0", in bits 22:21. No action needed. 375 break; 376 } 377 } 378 } 379 380 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, 381 uint64_t Offset, 382 uint32_t Value, 383 uint32_t Type, 384 int32_t Addend) { 385 // TODO: Add Thumb relocations. 386 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress + 387 Offset); 388 uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset); 389 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF); 390 Value += Addend; 391 392 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " 393 << Section.Address + Offset 394 << " FinalAddress: " << format("%p",FinalAddress) 395 << " Value: " << format("%x",Value) 396 << " Type: " << format("%x",Type) 397 << " Addend: " << format("%x",Addend) 398 << "\n"); 399 400 switch(Type) { 401 default: 402 llvm_unreachable("Not implemented relocation type!"); 403 404 // Write a 32bit value to relocation address, taking into account the 405 // implicit addend encoded in the target. 406 case ELF::R_ARM_TARGET1: 407 case ELF::R_ARM_ABS32: 408 *TargetPtr = *Placeholder + Value; 409 break; 410 // Write first 16 bit of 32 bit value to the mov instruction. 411 // Last 4 bit should be shifted. 412 case ELF::R_ARM_MOVW_ABS_NC: 413 // We are not expecting any other addend in the relocation address. 414 // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2 415 // non-contiguous fields. 416 assert((*Placeholder & 0x000F0FFF) == 0); 417 Value = Value & 0xFFFF; 418 *TargetPtr = *Placeholder | (Value & 0xFFF); 419 *TargetPtr |= ((Value >> 12) & 0xF) << 16; 420 break; 421 // Write last 16 bit of 32 bit value to the mov instruction. 422 // Last 4 bit should be shifted. 423 case ELF::R_ARM_MOVT_ABS: 424 // We are not expecting any other addend in the relocation address. 425 // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC. 426 assert((*Placeholder & 0x000F0FFF) == 0); 427 428 Value = (Value >> 16) & 0xFFFF; 429 *TargetPtr = *Placeholder | (Value & 0xFFF); 430 *TargetPtr |= ((Value >> 12) & 0xF) << 16; 431 break; 432 // Write 24 bit relative value to the branch instruction. 433 case ELF::R_ARM_PC24 : // Fall through. 434 case ELF::R_ARM_CALL : // Fall through. 435 case ELF::R_ARM_JUMP24: { 436 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); 437 RelValue = (RelValue & 0x03FFFFFC) >> 2; 438 assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE); 439 *TargetPtr &= 0xFF000000; 440 *TargetPtr |= RelValue; 441 break; 442 } 443 case ELF::R_ARM_PRIVATE_0: 444 // This relocation is reserved by the ARM ELF ABI for internal use. We 445 // appropriate it here to act as an R_ARM_ABS32 without any addend for use 446 // in the stubs created during JIT (which can't put an addend into the 447 // original object file). 448 *TargetPtr = Value; 449 break; 450 } 451 } 452 453 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section, 454 uint64_t Offset, 455 uint32_t Value, 456 uint32_t Type, 457 int32_t Addend) { 458 uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset); 459 Value += Addend; 460 461 DEBUG(dbgs() << "resolveMipselocation, LocalAddress: " 462 << Section.Address + Offset 463 << " FinalAddress: " 464 << format("%p",Section.LoadAddress + Offset) 465 << " Value: " << format("%x",Value) 466 << " Type: " << format("%x",Type) 467 << " Addend: " << format("%x",Addend) 468 << "\n"); 469 470 switch(Type) { 471 default: 472 llvm_unreachable("Not implemented relocation type!"); 473 break; 474 case ELF::R_MIPS_32: 475 *TargetPtr = Value + (*TargetPtr); 476 break; 477 case ELF::R_MIPS_26: 478 *TargetPtr = ((*TargetPtr) & 0xfc000000) | (( Value & 0x0fffffff) >> 2); 479 break; 480 case ELF::R_MIPS_HI16: 481 // Get the higher 16-bits. Also add 1 if bit 15 is 1. 482 Value += ((*TargetPtr) & 0x0000ffff) << 16; 483 *TargetPtr = ((*TargetPtr) & 0xffff0000) | 484 (((Value + 0x8000) >> 16) & 0xffff); 485 break; 486 case ELF::R_MIPS_LO16: 487 Value += ((*TargetPtr) & 0x0000ffff); 488 *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff); 489 break; 490 } 491 } 492 493 // Return the .TOC. section address to R_PPC64_TOC relocations. 494 uint64_t RuntimeDyldELF::findPPC64TOC() const { 495 // The TOC consists of sections .got, .toc, .tocbss, .plt in that 496 // order. The TOC starts where the first of these sections starts. 497 SectionList::const_iterator it = Sections.begin(); 498 SectionList::const_iterator ite = Sections.end(); 499 for (; it != ite; ++it) { 500 if (it->Name == ".got" || 501 it->Name == ".toc" || 502 it->Name == ".tocbss" || 503 it->Name == ".plt") 504 break; 505 } 506 if (it == ite) { 507 // This may happen for 508 // * references to TOC base base (sym@toc, .odp relocation) without 509 // a .toc directive. 510 // In this case just use the first section (which is usually 511 // the .odp) since the code won't reference the .toc base 512 // directly. 513 it = Sections.begin(); 514 } 515 assert (it != ite); 516 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 517 // thus permitting a full 64 Kbytes segment. 518 return it->LoadAddress + 0x8000; 519 } 520 521 // Returns the sections and offset associated with the ODP entry referenced 522 // by Symbol. 523 void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj, 524 ObjSectionToIDMap &LocalSections, 525 RelocationValueRef &Rel) { 526 // Get the ELF symbol value (st_value) to compare with Relocation offset in 527 // .opd entries 528 529 error_code err; 530 for (section_iterator si = Obj.begin_sections(), 531 se = Obj.end_sections(); si != se; si.increment(err)) { 532 section_iterator RelSecI = si->getRelocatedSection(); 533 if (RelSecI == Obj.end_sections()) 534 continue; 535 536 StringRef RelSectionName; 537 check(RelSecI->getName(RelSectionName)); 538 if (RelSectionName != ".opd") 539 continue; 540 541 for (relocation_iterator i = si->begin_relocations(), 542 e = si->end_relocations(); i != e;) { 543 check(err); 544 545 // The R_PPC64_ADDR64 relocation indicates the first field 546 // of a .opd entry 547 uint64_t TypeFunc; 548 check(i->getType(TypeFunc)); 549 if (TypeFunc != ELF::R_PPC64_ADDR64) { 550 i.increment(err); 551 continue; 552 } 553 554 uint64_t TargetSymbolOffset; 555 symbol_iterator TargetSymbol = i->getSymbol(); 556 check(i->getOffset(TargetSymbolOffset)); 557 int64_t Addend; 558 check(getELFRelocationAddend(*i, Addend)); 559 560 i = i.increment(err); 561 if (i == e) 562 break; 563 check(err); 564 565 // Just check if following relocation is a R_PPC64_TOC 566 uint64_t TypeTOC; 567 check(i->getType(TypeTOC)); 568 if (TypeTOC != ELF::R_PPC64_TOC) 569 continue; 570 571 // Finally compares the Symbol value and the target symbol offset 572 // to check if this .opd entry refers to the symbol the relocation 573 // points to. 574 if (Rel.Addend != (intptr_t)TargetSymbolOffset) 575 continue; 576 577 section_iterator tsi(Obj.end_sections()); 578 check(TargetSymbol->getSection(tsi)); 579 Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections); 580 Rel.Addend = (intptr_t)Addend; 581 return; 582 } 583 } 584 llvm_unreachable("Attempting to get address of ODP entry!"); 585 } 586 587 // Relocation masks following the #lo(value), #hi(value), #higher(value), 588 // and #highest(value) macros defined in section 4.5.1. Relocation Types 589 // in PPC-elf64abi document. 590 // 591 static inline 592 uint16_t applyPPClo (uint64_t value) 593 { 594 return value & 0xffff; 595 } 596 597 static inline 598 uint16_t applyPPChi (uint64_t value) 599 { 600 return (value >> 16) & 0xffff; 601 } 602 603 static inline 604 uint16_t applyPPChigher (uint64_t value) 605 { 606 return (value >> 32) & 0xffff; 607 } 608 609 static inline 610 uint16_t applyPPChighest (uint64_t value) 611 { 612 return (value >> 48) & 0xffff; 613 } 614 615 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, 616 uint64_t Offset, 617 uint64_t Value, 618 uint32_t Type, 619 int64_t Addend) { 620 uint8_t* LocalAddress = Section.Address + Offset; 621 switch (Type) { 622 default: 623 llvm_unreachable("Relocation type not implemented yet!"); 624 break; 625 case ELF::R_PPC64_ADDR16_LO : 626 writeInt16BE(LocalAddress, applyPPClo (Value + Addend)); 627 break; 628 case ELF::R_PPC64_ADDR16_HI : 629 writeInt16BE(LocalAddress, applyPPChi (Value + Addend)); 630 break; 631 case ELF::R_PPC64_ADDR16_HIGHER : 632 writeInt16BE(LocalAddress, applyPPChigher (Value + Addend)); 633 break; 634 case ELF::R_PPC64_ADDR16_HIGHEST : 635 writeInt16BE(LocalAddress, applyPPChighest (Value + Addend)); 636 break; 637 case ELF::R_PPC64_ADDR14 : { 638 assert(((Value + Addend) & 3) == 0); 639 // Preserve the AA/LK bits in the branch instruction 640 uint8_t aalk = *(LocalAddress+3); 641 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); 642 } break; 643 case ELF::R_PPC64_ADDR32 : { 644 int32_t Result = static_cast<int32_t>(Value + Addend); 645 if (SignExtend32<32>(Result) != Result) 646 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); 647 writeInt32BE(LocalAddress, Result); 648 } break; 649 case ELF::R_PPC64_REL24 : { 650 uint64_t FinalAddress = (Section.LoadAddress + Offset); 651 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 652 if (SignExtend32<24>(delta) != delta) 653 llvm_unreachable("Relocation R_PPC64_REL24 overflow"); 654 // Generates a 'bl <address>' instruction 655 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); 656 } break; 657 case ELF::R_PPC64_REL32 : { 658 uint64_t FinalAddress = (Section.LoadAddress + Offset); 659 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); 660 if (SignExtend32<32>(delta) != delta) 661 llvm_unreachable("Relocation R_PPC64_REL32 overflow"); 662 writeInt32BE(LocalAddress, delta); 663 } break; 664 case ELF::R_PPC64_REL64: { 665 uint64_t FinalAddress = (Section.LoadAddress + Offset); 666 uint64_t Delta = Value - FinalAddress + Addend; 667 writeInt64BE(LocalAddress, Delta); 668 } break; 669 case ELF::R_PPC64_ADDR64 : 670 writeInt64BE(LocalAddress, Value + Addend); 671 break; 672 case ELF::R_PPC64_TOC : 673 writeInt64BE(LocalAddress, findPPC64TOC()); 674 break; 675 case ELF::R_PPC64_TOC16 : { 676 uint64_t TOCStart = findPPC64TOC(); 677 Value = applyPPClo((Value + Addend) - TOCStart); 678 writeInt16BE(LocalAddress, applyPPClo(Value)); 679 } break; 680 case ELF::R_PPC64_TOC16_DS : { 681 uint64_t TOCStart = findPPC64TOC(); 682 Value = ((Value + Addend) - TOCStart); 683 writeInt16BE(LocalAddress, applyPPClo(Value)); 684 } break; 685 } 686 } 687 688 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, 689 uint64_t Offset, 690 uint64_t Value, 691 uint32_t Type, 692 int64_t Addend) { 693 uint8_t *LocalAddress = Section.Address + Offset; 694 switch (Type) { 695 default: 696 llvm_unreachable("Relocation type not implemented yet!"); 697 break; 698 case ELF::R_390_PC16DBL: 699 case ELF::R_390_PLT16DBL: { 700 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); 701 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); 702 writeInt16BE(LocalAddress, Delta / 2); 703 break; 704 } 705 case ELF::R_390_PC32DBL: 706 case ELF::R_390_PLT32DBL: { 707 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); 708 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); 709 writeInt32BE(LocalAddress, Delta / 2); 710 break; 711 } 712 case ELF::R_390_PC32: { 713 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); 714 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); 715 writeInt32BE(LocalAddress, Delta); 716 break; 717 } 718 case ELF::R_390_64: 719 writeInt64BE(LocalAddress, Value + Addend); 720 break; 721 } 722 } 723 724 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, 725 uint64_t Value) { 726 const SectionEntry &Section = Sections[RE.SectionID]; 727 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend); 728 } 729 730 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, 731 uint64_t Offset, 732 uint64_t Value, 733 uint32_t Type, 734 int64_t Addend) { 735 switch (Arch) { 736 case Triple::x86_64: 737 resolveX86_64Relocation(Section, Offset, Value, Type, Addend); 738 break; 739 case Triple::x86: 740 resolveX86Relocation(Section, Offset, 741 (uint32_t)(Value & 0xffffffffL), Type, 742 (uint32_t)(Addend & 0xffffffffL)); 743 break; 744 case Triple::aarch64: 745 resolveAArch64Relocation(Section, Offset, Value, Type, Addend); 746 break; 747 case Triple::arm: // Fall through. 748 case Triple::thumb: 749 resolveARMRelocation(Section, Offset, 750 (uint32_t)(Value & 0xffffffffL), Type, 751 (uint32_t)(Addend & 0xffffffffL)); 752 break; 753 case Triple::mips: // Fall through. 754 case Triple::mipsel: 755 resolveMIPSRelocation(Section, Offset, 756 (uint32_t)(Value & 0xffffffffL), Type, 757 (uint32_t)(Addend & 0xffffffffL)); 758 break; 759 case Triple::ppc64: 760 resolvePPC64Relocation(Section, Offset, Value, Type, Addend); 761 break; 762 case Triple::systemz: 763 resolveSystemZRelocation(Section, Offset, Value, Type, Addend); 764 break; 765 default: llvm_unreachable("Unsupported CPU type!"); 766 } 767 } 768 769 void RuntimeDyldELF::processRelocationRef(unsigned SectionID, 770 RelocationRef RelI, 771 ObjectImage &Obj, 772 ObjSectionToIDMap &ObjSectionToID, 773 const SymbolTableMap &Symbols, 774 StubMap &Stubs) { 775 uint64_t RelType; 776 Check(RelI.getType(RelType)); 777 int64_t Addend; 778 Check(getELFRelocationAddend(RelI, Addend)); 779 symbol_iterator Symbol = RelI.getSymbol(); 780 781 // Obtain the symbol name which is referenced in the relocation 782 StringRef TargetName; 783 if (Symbol != Obj.end_symbols()) 784 Symbol->getName(TargetName); 785 DEBUG(dbgs() << "\t\tRelType: " << RelType 786 << " Addend: " << Addend 787 << " TargetName: " << TargetName 788 << "\n"); 789 RelocationValueRef Value; 790 // First search for the symbol in the local symbol table 791 SymbolTableMap::const_iterator lsi = Symbols.end(); 792 SymbolRef::Type SymType = SymbolRef::ST_Unknown; 793 if (Symbol != Obj.end_symbols()) { 794 lsi = Symbols.find(TargetName.data()); 795 Symbol->getType(SymType); 796 } 797 if (lsi != Symbols.end()) { 798 Value.SectionID = lsi->second.first; 799 Value.Addend = lsi->second.second + Addend; 800 } else { 801 // Search for the symbol in the global symbol table 802 SymbolTableMap::const_iterator gsi = GlobalSymbolTable.end(); 803 if (Symbol != Obj.end_symbols()) 804 gsi = GlobalSymbolTable.find(TargetName.data()); 805 if (gsi != GlobalSymbolTable.end()) { 806 Value.SectionID = gsi->second.first; 807 Value.Addend = gsi->second.second + Addend; 808 } else { 809 switch (SymType) { 810 case SymbolRef::ST_Debug: { 811 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously 812 // and can be changed by another developers. Maybe best way is add 813 // a new symbol type ST_Section to SymbolRef and use it. 814 section_iterator si(Obj.end_sections()); 815 Symbol->getSection(si); 816 if (si == Obj.end_sections()) 817 llvm_unreachable("Symbol section not found, bad object file format!"); 818 DEBUG(dbgs() << "\t\tThis is section symbol\n"); 819 // Default to 'true' in case isText fails (though it never does). 820 bool isCode = true; 821 si->isText(isCode); 822 Value.SectionID = findOrEmitSection(Obj, 823 (*si), 824 isCode, 825 ObjSectionToID); 826 Value.Addend = Addend; 827 break; 828 } 829 case SymbolRef::ST_Unknown: { 830 Value.SymbolName = TargetName.data(); 831 Value.Addend = Addend; 832 break; 833 } 834 default: 835 llvm_unreachable("Unresolved symbol type!"); 836 break; 837 } 838 } 839 } 840 uint64_t Offset; 841 Check(RelI.getOffset(Offset)); 842 843 DEBUG(dbgs() << "\t\tSectionID: " << SectionID 844 << " Offset: " << Offset 845 << "\n"); 846 if (Arch == Triple::aarch64 && 847 (RelType == ELF::R_AARCH64_CALL26 || 848 RelType == ELF::R_AARCH64_JUMP26)) { 849 // This is an AArch64 branch relocation, need to use a stub function. 850 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); 851 SectionEntry &Section = Sections[SectionID]; 852 853 // Look for an existing stub. 854 StubMap::const_iterator i = Stubs.find(Value); 855 if (i != Stubs.end()) { 856 resolveRelocation(Section, Offset, 857 (uint64_t)Section.Address + i->second, RelType, 0); 858 DEBUG(dbgs() << " Stub function found\n"); 859 } else { 860 // Create a new stub function. 861 DEBUG(dbgs() << " Create a new stub function\n"); 862 Stubs[Value] = Section.StubOffset; 863 uint8_t *StubTargetAddr = createStubFunction(Section.Address + 864 Section.StubOffset); 865 866 RelocationEntry REmovz_g3(SectionID, 867 StubTargetAddr - Section.Address, 868 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); 869 RelocationEntry REmovk_g2(SectionID, 870 StubTargetAddr - Section.Address + 4, 871 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); 872 RelocationEntry REmovk_g1(SectionID, 873 StubTargetAddr - Section.Address + 8, 874 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); 875 RelocationEntry REmovk_g0(SectionID, 876 StubTargetAddr - Section.Address + 12, 877 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); 878 879 if (Value.SymbolName) { 880 addRelocationForSymbol(REmovz_g3, Value.SymbolName); 881 addRelocationForSymbol(REmovk_g2, Value.SymbolName); 882 addRelocationForSymbol(REmovk_g1, Value.SymbolName); 883 addRelocationForSymbol(REmovk_g0, Value.SymbolName); 884 } else { 885 addRelocationForSection(REmovz_g3, Value.SectionID); 886 addRelocationForSection(REmovk_g2, Value.SectionID); 887 addRelocationForSection(REmovk_g1, Value.SectionID); 888 addRelocationForSection(REmovk_g0, Value.SectionID); 889 } 890 resolveRelocation(Section, Offset, 891 (uint64_t)Section.Address + Section.StubOffset, 892 RelType, 0); 893 Section.StubOffset += getMaxStubSize(); 894 } 895 } else if (Arch == Triple::arm && 896 (RelType == ELF::R_ARM_PC24 || 897 RelType == ELF::R_ARM_CALL || 898 RelType == ELF::R_ARM_JUMP24)) { 899 // This is an ARM branch relocation, need to use a stub function. 900 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation."); 901 SectionEntry &Section = Sections[SectionID]; 902 903 // Look for an existing stub. 904 StubMap::const_iterator i = Stubs.find(Value); 905 if (i != Stubs.end()) { 906 resolveRelocation(Section, Offset, 907 (uint64_t)Section.Address + i->second, RelType, 0); 908 DEBUG(dbgs() << " Stub function found\n"); 909 } else { 910 // Create a new stub function. 911 DEBUG(dbgs() << " Create a new stub function\n"); 912 Stubs[Value] = Section.StubOffset; 913 uint8_t *StubTargetAddr = createStubFunction(Section.Address + 914 Section.StubOffset); 915 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, 916 ELF::R_ARM_PRIVATE_0, Value.Addend); 917 if (Value.SymbolName) 918 addRelocationForSymbol(RE, Value.SymbolName); 919 else 920 addRelocationForSection(RE, Value.SectionID); 921 922 resolveRelocation(Section, Offset, 923 (uint64_t)Section.Address + Section.StubOffset, 924 RelType, 0); 925 Section.StubOffset += getMaxStubSize(); 926 } 927 } else if ((Arch == Triple::mipsel || Arch == Triple::mips) && 928 RelType == ELF::R_MIPS_26) { 929 // This is an Mips branch relocation, need to use a stub function. 930 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); 931 SectionEntry &Section = Sections[SectionID]; 932 uint8_t *Target = Section.Address + Offset; 933 uint32_t *TargetAddress = (uint32_t *)Target; 934 935 // Extract the addend from the instruction. 936 uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2; 937 938 Value.Addend += Addend; 939 940 // Look up for existing stub. 941 StubMap::const_iterator i = Stubs.find(Value); 942 if (i != Stubs.end()) { 943 resolveRelocation(Section, Offset, 944 (uint64_t)Section.Address + i->second, RelType, 0); 945 DEBUG(dbgs() << " Stub function found\n"); 946 } else { 947 // Create a new stub function. 948 DEBUG(dbgs() << " Create a new stub function\n"); 949 Stubs[Value] = Section.StubOffset; 950 uint8_t *StubTargetAddr = createStubFunction(Section.Address + 951 Section.StubOffset); 952 953 // Creating Hi and Lo relocations for the filled stub instructions. 954 RelocationEntry REHi(SectionID, 955 StubTargetAddr - Section.Address, 956 ELF::R_MIPS_HI16, Value.Addend); 957 RelocationEntry RELo(SectionID, 958 StubTargetAddr - Section.Address + 4, 959 ELF::R_MIPS_LO16, Value.Addend); 960 961 if (Value.SymbolName) { 962 addRelocationForSymbol(REHi, Value.SymbolName); 963 addRelocationForSymbol(RELo, Value.SymbolName); 964 } else { 965 addRelocationForSection(REHi, Value.SectionID); 966 addRelocationForSection(RELo, Value.SectionID); 967 } 968 969 resolveRelocation(Section, Offset, 970 (uint64_t)Section.Address + Section.StubOffset, 971 RelType, 0); 972 Section.StubOffset += getMaxStubSize(); 973 } 974 } else if (Arch == Triple::ppc64) { 975 if (RelType == ELF::R_PPC64_REL24) { 976 // A PPC branch relocation will need a stub function if the target is 977 // an external symbol (Symbol::ST_Unknown) or if the target address 978 // is not within the signed 24-bits branch address. 979 SectionEntry &Section = Sections[SectionID]; 980 uint8_t *Target = Section.Address + Offset; 981 bool RangeOverflow = false; 982 if (SymType != SymbolRef::ST_Unknown) { 983 // A function call may points to the .opd entry, so the final symbol value 984 // in calculated based in the relocation values in .opd section. 985 findOPDEntrySection(Obj, ObjSectionToID, Value); 986 uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend; 987 int32_t delta = static_cast<int32_t>(Target - RelocTarget); 988 // If it is within 24-bits branch range, just set the branch target 989 if (SignExtend32<24>(delta) == delta) { 990 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 991 if (Value.SymbolName) 992 addRelocationForSymbol(RE, Value.SymbolName); 993 else 994 addRelocationForSection(RE, Value.SectionID); 995 } else { 996 RangeOverflow = true; 997 } 998 } 999 if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) { 1000 // It is an external symbol (SymbolRef::ST_Unknown) or within a range 1001 // larger than 24-bits. 1002 StubMap::const_iterator i = Stubs.find(Value); 1003 if (i != Stubs.end()) { 1004 // Symbol function stub already created, just relocate to it 1005 resolveRelocation(Section, Offset, 1006 (uint64_t)Section.Address + i->second, RelType, 0); 1007 DEBUG(dbgs() << " Stub function found\n"); 1008 } else { 1009 // Create a new stub function. 1010 DEBUG(dbgs() << " Create a new stub function\n"); 1011 Stubs[Value] = Section.StubOffset; 1012 uint8_t *StubTargetAddr = createStubFunction(Section.Address + 1013 Section.StubOffset); 1014 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, 1015 ELF::R_PPC64_ADDR64, Value.Addend); 1016 1017 // Generates the 64-bits address loads as exemplified in section 1018 // 4.5.1 in PPC64 ELF ABI. 1019 RelocationEntry REhst(SectionID, 1020 StubTargetAddr - Section.Address + 2, 1021 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); 1022 RelocationEntry REhr(SectionID, 1023 StubTargetAddr - Section.Address + 6, 1024 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); 1025 RelocationEntry REh(SectionID, 1026 StubTargetAddr - Section.Address + 14, 1027 ELF::R_PPC64_ADDR16_HI, Value.Addend); 1028 RelocationEntry REl(SectionID, 1029 StubTargetAddr - Section.Address + 18, 1030 ELF::R_PPC64_ADDR16_LO, Value.Addend); 1031 1032 if (Value.SymbolName) { 1033 addRelocationForSymbol(REhst, Value.SymbolName); 1034 addRelocationForSymbol(REhr, Value.SymbolName); 1035 addRelocationForSymbol(REh, Value.SymbolName); 1036 addRelocationForSymbol(REl, Value.SymbolName); 1037 } else { 1038 addRelocationForSection(REhst, Value.SectionID); 1039 addRelocationForSection(REhr, Value.SectionID); 1040 addRelocationForSection(REh, Value.SectionID); 1041 addRelocationForSection(REl, Value.SectionID); 1042 } 1043 1044 resolveRelocation(Section, Offset, 1045 (uint64_t)Section.Address + Section.StubOffset, 1046 RelType, 0); 1047 if (SymType == SymbolRef::ST_Unknown) 1048 // Restore the TOC for external calls 1049 writeInt32BE(Target+4, 0xE8410028); // ld r2,40(r1) 1050 Section.StubOffset += getMaxStubSize(); 1051 } 1052 } 1053 } else { 1054 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1055 // Extra check to avoid relocation againt empty symbols (usually 1056 // the R_PPC64_TOC). 1057 if (Value.SymbolName && !TargetName.empty()) 1058 addRelocationForSymbol(RE, Value.SymbolName); 1059 else 1060 addRelocationForSection(RE, Value.SectionID); 1061 } 1062 } else if (Arch == Triple::systemz && 1063 (RelType == ELF::R_390_PLT32DBL || 1064 RelType == ELF::R_390_GOTENT)) { 1065 // Create function stubs for both PLT and GOT references, regardless of 1066 // whether the GOT reference is to data or code. The stub contains the 1067 // full address of the symbol, as needed by GOT references, and the 1068 // executable part only adds an overhead of 8 bytes. 1069 // 1070 // We could try to conserve space by allocating the code and data 1071 // parts of the stub separately. However, as things stand, we allocate 1072 // a stub for every relocation, so using a GOT in JIT code should be 1073 // no less space efficient than using an explicit constant pool. 1074 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); 1075 SectionEntry &Section = Sections[SectionID]; 1076 1077 // Look for an existing stub. 1078 StubMap::const_iterator i = Stubs.find(Value); 1079 uintptr_t StubAddress; 1080 if (i != Stubs.end()) { 1081 StubAddress = uintptr_t(Section.Address) + i->second; 1082 DEBUG(dbgs() << " Stub function found\n"); 1083 } else { 1084 // Create a new stub function. 1085 DEBUG(dbgs() << " Create a new stub function\n"); 1086 1087 uintptr_t BaseAddress = uintptr_t(Section.Address); 1088 uintptr_t StubAlignment = getStubAlignment(); 1089 StubAddress = (BaseAddress + Section.StubOffset + 1090 StubAlignment - 1) & -StubAlignment; 1091 unsigned StubOffset = StubAddress - BaseAddress; 1092 1093 Stubs[Value] = StubOffset; 1094 createStubFunction((uint8_t *)StubAddress); 1095 RelocationEntry RE(SectionID, StubOffset + 8, 1096 ELF::R_390_64, Value.Addend - Addend); 1097 if (Value.SymbolName) 1098 addRelocationForSymbol(RE, Value.SymbolName); 1099 else 1100 addRelocationForSection(RE, Value.SectionID); 1101 Section.StubOffset = StubOffset + getMaxStubSize(); 1102 } 1103 1104 if (RelType == ELF::R_390_GOTENT) 1105 resolveRelocation(Section, Offset, StubAddress + 8, 1106 ELF::R_390_PC32DBL, Addend); 1107 else 1108 resolveRelocation(Section, Offset, StubAddress, RelType, Addend); 1109 } else { 1110 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); 1111 if (Value.SymbolName) 1112 addRelocationForSymbol(RE, Value.SymbolName); 1113 else 1114 addRelocationForSection(RE, Value.SectionID); 1115 } 1116 } 1117 1118 bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const { 1119 if (Buffer->getBufferSize() < strlen(ELF::ElfMagic)) 1120 return false; 1121 return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0; 1122 } 1123 } // namespace llvm 1124