1 //===- ObjectFile.h - File format independent object file -------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file declares a file format independent ObjectFile class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_OBJECT_OBJECTFILE_H 14 #define LLVM_OBJECT_OBJECTFILE_H 15 16 #include "llvm/ADT/ArrayRef.h" 17 #include "llvm/ADT/Hashing.h" 18 #include "llvm/ADT/StringRef.h" 19 #include "llvm/ADT/Triple.h" 20 #include "llvm/ADT/iterator_range.h" 21 #include "llvm/BinaryFormat/Magic.h" 22 #include "llvm/BinaryFormat/Swift.h" 23 #include "llvm/Object/Binary.h" 24 #include "llvm/Object/Error.h" 25 #include "llvm/Object/SymbolicFile.h" 26 #include "llvm/Support/Casting.h" 27 #include "llvm/Support/Error.h" 28 #include "llvm/Support/MemoryBufferRef.h" 29 #include <cassert> 30 #include <cstdint> 31 #include <memory> 32 33 namespace llvm { 34 35 class SubtargetFeatures; 36 37 namespace object { 38 39 class COFFObjectFile; 40 class MachOObjectFile; 41 class ObjectFile; 42 class SectionRef; 43 class SymbolRef; 44 class symbol_iterator; 45 class WasmObjectFile; 46 47 using section_iterator = content_iterator<SectionRef>; 48 49 /// This is a value type class that represents a single relocation in the list 50 /// of relocations in the object file. 51 class RelocationRef { 52 DataRefImpl RelocationPimpl; 53 const ObjectFile *OwningObject = nullptr; 54 55 public: 56 RelocationRef() = default; 57 RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner); 58 59 bool operator==(const RelocationRef &Other) const; 60 61 void moveNext(); 62 63 uint64_t getOffset() const; 64 symbol_iterator getSymbol() const; 65 uint64_t getType() const; 66 67 /// Get a string that represents the type of this relocation. 68 /// 69 /// This is for display purposes only. 70 void getTypeName(SmallVectorImpl<char> &Result) const; 71 72 DataRefImpl getRawDataRefImpl() const; 73 const ObjectFile *getObject() const; 74 }; 75 76 using relocation_iterator = content_iterator<RelocationRef>; 77 78 /// This is a value type class that represents a single section in the list of 79 /// sections in the object file. 80 class SectionRef { 81 friend class SymbolRef; 82 83 DataRefImpl SectionPimpl; 84 const ObjectFile *OwningObject = nullptr; 85 86 public: 87 SectionRef() = default; 88 SectionRef(DataRefImpl SectionP, const ObjectFile *Owner); 89 90 bool operator==(const SectionRef &Other) const; 91 bool operator!=(const SectionRef &Other) const; 92 bool operator<(const SectionRef &Other) const; 93 94 void moveNext(); 95 96 Expected<StringRef> getName() const; 97 uint64_t getAddress() const; 98 uint64_t getIndex() const; 99 uint64_t getSize() const; 100 Expected<StringRef> getContents() const; 101 102 /// Get the alignment of this section as the actual value (not log 2). 103 uint64_t getAlignment() const; 104 105 bool isCompressed() const; 106 /// Whether this section contains instructions. 107 bool isText() const; 108 /// Whether this section contains data, not instructions. 109 bool isData() const; 110 /// Whether this section contains BSS uninitialized data. 111 bool isBSS() const; 112 bool isVirtual() const; 113 bool isBitcode() const; 114 bool isStripped() const; 115 116 /// Whether this section will be placed in the text segment, according to the 117 /// Berkeley size format. This is true if the section is allocatable, and 118 /// contains either code or readonly data. 119 bool isBerkeleyText() const; 120 /// Whether this section will be placed in the data segment, according to the 121 /// Berkeley size format. This is true if the section is allocatable and 122 /// contains data (e.g. PROGBITS), but is not text. 123 bool isBerkeleyData() const; 124 125 /// Whether this section is a debug section. 126 bool isDebugSection() const; 127 128 bool containsSymbol(SymbolRef S) const; 129 130 relocation_iterator relocation_begin() const; 131 relocation_iterator relocation_end() const; 132 iterator_range<relocation_iterator> relocations() const { 133 return make_range(relocation_begin(), relocation_end()); 134 } 135 136 /// Returns the related section if this section contains relocations. The 137 /// returned section may or may not have applied its relocations. 138 Expected<section_iterator> getRelocatedSection() const; 139 140 DataRefImpl getRawDataRefImpl() const; 141 const ObjectFile *getObject() const; 142 }; 143 144 struct SectionedAddress { 145 const static uint64_t UndefSection = UINT64_MAX; 146 147 uint64_t Address = 0; 148 uint64_t SectionIndex = UndefSection; 149 }; 150 151 inline bool operator<(const SectionedAddress &LHS, 152 const SectionedAddress &RHS) { 153 return std::tie(LHS.SectionIndex, LHS.Address) < 154 std::tie(RHS.SectionIndex, RHS.Address); 155 } 156 157 inline bool operator==(const SectionedAddress &LHS, 158 const SectionedAddress &RHS) { 159 return std::tie(LHS.SectionIndex, LHS.Address) == 160 std::tie(RHS.SectionIndex, RHS.Address); 161 } 162 163 raw_ostream &operator<<(raw_ostream &OS, const SectionedAddress &Addr); 164 165 /// This is a value type class that represents a single symbol in the list of 166 /// symbols in the object file. 167 class SymbolRef : public BasicSymbolRef { 168 friend class SectionRef; 169 170 public: 171 enum Type { 172 ST_Unknown, // Type not specified 173 ST_Other, 174 ST_Data, 175 ST_Debug, 176 ST_File, 177 ST_Function, 178 }; 179 180 SymbolRef() = default; 181 SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner); 182 SymbolRef(const BasicSymbolRef &B) : BasicSymbolRef(B) { 183 assert(isa<ObjectFile>(BasicSymbolRef::getObject())); 184 } 185 186 Expected<StringRef> getName() const; 187 /// Returns the symbol virtual address (i.e. address at which it will be 188 /// mapped). 189 Expected<uint64_t> getAddress() const; 190 191 /// Return the value of the symbol depending on the object this can be an 192 /// offset or a virtual address. 193 Expected<uint64_t> getValue() const; 194 195 /// Get the alignment of this symbol as the actual value (not log 2). 196 uint32_t getAlignment() const; 197 uint64_t getCommonSize() const; 198 Expected<SymbolRef::Type> getType() const; 199 200 /// Get section this symbol is defined in reference to. Result is 201 /// end_sections() if it is undefined or is an absolute symbol. 202 Expected<section_iterator> getSection() const; 203 204 const ObjectFile *getObject() const; 205 }; 206 207 class symbol_iterator : public basic_symbol_iterator { 208 public: 209 symbol_iterator(SymbolRef Sym) : basic_symbol_iterator(Sym) {} 210 symbol_iterator(const basic_symbol_iterator &B) 211 : basic_symbol_iterator(SymbolRef(B->getRawDataRefImpl(), 212 cast<ObjectFile>(B->getObject()))) {} 213 214 const SymbolRef *operator->() const { 215 const BasicSymbolRef &P = basic_symbol_iterator::operator *(); 216 return static_cast<const SymbolRef*>(&P); 217 } 218 219 const SymbolRef &operator*() const { 220 const BasicSymbolRef &P = basic_symbol_iterator::operator *(); 221 return static_cast<const SymbolRef&>(P); 222 } 223 }; 224 225 /// This class is the base class for all object file types. Concrete instances 226 /// of this object are created by createObjectFile, which figures out which type 227 /// to create. 228 class ObjectFile : public SymbolicFile { 229 virtual void anchor(); 230 231 protected: 232 ObjectFile(unsigned int Type, MemoryBufferRef Source); 233 234 const uint8_t *base() const { 235 return reinterpret_cast<const uint8_t *>(Data.getBufferStart()); 236 } 237 238 // These functions are for SymbolRef to call internally. The main goal of 239 // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol 240 // entry in the memory mapped object file. SymbolPimpl cannot contain any 241 // virtual functions because then it could not point into the memory mapped 242 // file. 243 // 244 // Implementations assume that the DataRefImpl is valid and has not been 245 // modified externally. It's UB otherwise. 246 friend class SymbolRef; 247 248 virtual Expected<StringRef> getSymbolName(DataRefImpl Symb) const = 0; 249 Error printSymbolName(raw_ostream &OS, 250 DataRefImpl Symb) const override; 251 virtual Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const = 0; 252 virtual uint64_t getSymbolValueImpl(DataRefImpl Symb) const = 0; 253 virtual uint32_t getSymbolAlignment(DataRefImpl Symb) const; 254 virtual uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const = 0; 255 virtual Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const = 0; 256 virtual Expected<section_iterator> 257 getSymbolSection(DataRefImpl Symb) const = 0; 258 259 // Same as above for SectionRef. 260 friend class SectionRef; 261 262 virtual void moveSectionNext(DataRefImpl &Sec) const = 0; 263 virtual Expected<StringRef> getSectionName(DataRefImpl Sec) const = 0; 264 virtual uint64_t getSectionAddress(DataRefImpl Sec) const = 0; 265 virtual uint64_t getSectionIndex(DataRefImpl Sec) const = 0; 266 virtual uint64_t getSectionSize(DataRefImpl Sec) const = 0; 267 virtual Expected<ArrayRef<uint8_t>> 268 getSectionContents(DataRefImpl Sec) const = 0; 269 virtual uint64_t getSectionAlignment(DataRefImpl Sec) const = 0; 270 virtual bool isSectionCompressed(DataRefImpl Sec) const = 0; 271 virtual bool isSectionText(DataRefImpl Sec) const = 0; 272 virtual bool isSectionData(DataRefImpl Sec) const = 0; 273 virtual bool isSectionBSS(DataRefImpl Sec) const = 0; 274 // A section is 'virtual' if its contents aren't present in the object image. 275 virtual bool isSectionVirtual(DataRefImpl Sec) const = 0; 276 virtual bool isSectionBitcode(DataRefImpl Sec) const; 277 virtual bool isSectionStripped(DataRefImpl Sec) const; 278 virtual bool isBerkeleyText(DataRefImpl Sec) const; 279 virtual bool isBerkeleyData(DataRefImpl Sec) const; 280 virtual bool isDebugSection(DataRefImpl Sec) const; 281 virtual relocation_iterator section_rel_begin(DataRefImpl Sec) const = 0; 282 virtual relocation_iterator section_rel_end(DataRefImpl Sec) const = 0; 283 virtual Expected<section_iterator> getRelocatedSection(DataRefImpl Sec) const; 284 285 // Same as above for RelocationRef. 286 friend class RelocationRef; 287 virtual void moveRelocationNext(DataRefImpl &Rel) const = 0; 288 virtual uint64_t getRelocationOffset(DataRefImpl Rel) const = 0; 289 virtual symbol_iterator getRelocationSymbol(DataRefImpl Rel) const = 0; 290 virtual uint64_t getRelocationType(DataRefImpl Rel) const = 0; 291 virtual void getRelocationTypeName(DataRefImpl Rel, 292 SmallVectorImpl<char> &Result) const = 0; 293 294 virtual llvm::binaryformat::Swift5ReflectionSectionKind 295 mapReflectionSectionNameToEnumValue(StringRef SectionName) const { 296 return llvm::binaryformat::Swift5ReflectionSectionKind::unknown; 297 }; 298 299 Expected<uint64_t> getSymbolValue(DataRefImpl Symb) const; 300 301 public: 302 ObjectFile() = delete; 303 ObjectFile(const ObjectFile &other) = delete; 304 305 uint64_t getCommonSymbolSize(DataRefImpl Symb) const { 306 Expected<uint32_t> SymbolFlagsOrErr = getSymbolFlags(Symb); 307 if (!SymbolFlagsOrErr) 308 // TODO: Actually report errors helpfully. 309 report_fatal_error(SymbolFlagsOrErr.takeError()); 310 assert(*SymbolFlagsOrErr & SymbolRef::SF_Common); 311 return getCommonSymbolSizeImpl(Symb); 312 } 313 314 virtual std::vector<SectionRef> dynamic_relocation_sections() const { 315 return std::vector<SectionRef>(); 316 } 317 318 using symbol_iterator_range = iterator_range<symbol_iterator>; 319 symbol_iterator_range symbols() const { 320 return symbol_iterator_range(symbol_begin(), symbol_end()); 321 } 322 323 virtual section_iterator section_begin() const = 0; 324 virtual section_iterator section_end() const = 0; 325 326 using section_iterator_range = iterator_range<section_iterator>; 327 section_iterator_range sections() const { 328 return section_iterator_range(section_begin(), section_end()); 329 } 330 331 /// The number of bytes used to represent an address in this object 332 /// file format. 333 virtual uint8_t getBytesInAddress() const = 0; 334 335 virtual StringRef getFileFormatName() const = 0; 336 virtual Triple::ArchType getArch() const = 0; 337 virtual SubtargetFeatures getFeatures() const = 0; 338 virtual Optional<StringRef> tryGetCPUName() const { return None; }; 339 virtual void setARMSubArch(Triple &TheTriple) const { } 340 virtual Expected<uint64_t> getStartAddress() const { 341 return errorCodeToError(object_error::parse_failed); 342 }; 343 344 /// Create a triple from the data in this object file. 345 Triple makeTriple() const; 346 347 /// Maps a debug section name to a standard DWARF section name. 348 virtual StringRef mapDebugSectionName(StringRef Name) const { return Name; } 349 350 /// True if this is a relocatable object (.o/.obj). 351 virtual bool isRelocatableObject() const = 0; 352 353 /// True if the reflection section can be stripped by the linker. 354 bool isReflectionSectionStrippable( 355 llvm::binaryformat::Swift5ReflectionSectionKind ReflectionSectionKind) 356 const; 357 358 /// @returns Pointer to ObjectFile subclass to handle this type of object. 359 /// @param ObjectPath The path to the object file. ObjectPath.isObject must 360 /// return true. 361 /// Create ObjectFile from path. 362 static Expected<OwningBinary<ObjectFile>> 363 createObjectFile(StringRef ObjectPath); 364 365 static Expected<std::unique_ptr<ObjectFile>> 366 createObjectFile(MemoryBufferRef Object, llvm::file_magic Type, 367 bool InitContent = true); 368 static Expected<std::unique_ptr<ObjectFile>> 369 createObjectFile(MemoryBufferRef Object) { 370 return createObjectFile(Object, llvm::file_magic::unknown); 371 } 372 373 static bool classof(const Binary *v) { 374 return v->isObject(); 375 } 376 377 static Expected<std::unique_ptr<COFFObjectFile>> 378 createCOFFObjectFile(MemoryBufferRef Object); 379 380 static Expected<std::unique_ptr<ObjectFile>> 381 createXCOFFObjectFile(MemoryBufferRef Object, unsigned FileType); 382 383 static Expected<std::unique_ptr<ObjectFile>> 384 createELFObjectFile(MemoryBufferRef Object, bool InitContent = true); 385 386 static Expected<std::unique_ptr<MachOObjectFile>> 387 createMachOObjectFile(MemoryBufferRef Object, 388 uint32_t UniversalCputype = 0, 389 uint32_t UniversalIndex = 0); 390 391 static Expected<std::unique_ptr<WasmObjectFile>> 392 createWasmObjectFile(MemoryBufferRef Object); 393 }; 394 395 // Inline function definitions. 396 inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner) 397 : BasicSymbolRef(SymbolP, Owner) {} 398 399 inline Expected<StringRef> SymbolRef::getName() const { 400 return getObject()->getSymbolName(getRawDataRefImpl()); 401 } 402 403 inline Expected<uint64_t> SymbolRef::getAddress() const { 404 return getObject()->getSymbolAddress(getRawDataRefImpl()); 405 } 406 407 inline Expected<uint64_t> SymbolRef::getValue() const { 408 return getObject()->getSymbolValue(getRawDataRefImpl()); 409 } 410 411 inline uint32_t SymbolRef::getAlignment() const { 412 return getObject()->getSymbolAlignment(getRawDataRefImpl()); 413 } 414 415 inline uint64_t SymbolRef::getCommonSize() const { 416 return getObject()->getCommonSymbolSize(getRawDataRefImpl()); 417 } 418 419 inline Expected<section_iterator> SymbolRef::getSection() const { 420 return getObject()->getSymbolSection(getRawDataRefImpl()); 421 } 422 423 inline Expected<SymbolRef::Type> SymbolRef::getType() const { 424 return getObject()->getSymbolType(getRawDataRefImpl()); 425 } 426 427 inline const ObjectFile *SymbolRef::getObject() const { 428 const SymbolicFile *O = BasicSymbolRef::getObject(); 429 return cast<ObjectFile>(O); 430 } 431 432 /// SectionRef 433 inline SectionRef::SectionRef(DataRefImpl SectionP, 434 const ObjectFile *Owner) 435 : SectionPimpl(SectionP) 436 , OwningObject(Owner) {} 437 438 inline bool SectionRef::operator==(const SectionRef &Other) const { 439 return OwningObject == Other.OwningObject && 440 SectionPimpl == Other.SectionPimpl; 441 } 442 443 inline bool SectionRef::operator!=(const SectionRef &Other) const { 444 return !(*this == Other); 445 } 446 447 inline bool SectionRef::operator<(const SectionRef &Other) const { 448 assert(OwningObject == Other.OwningObject); 449 return SectionPimpl < Other.SectionPimpl; 450 } 451 452 inline void SectionRef::moveNext() { 453 return OwningObject->moveSectionNext(SectionPimpl); 454 } 455 456 inline Expected<StringRef> SectionRef::getName() const { 457 return OwningObject->getSectionName(SectionPimpl); 458 } 459 460 inline uint64_t SectionRef::getAddress() const { 461 return OwningObject->getSectionAddress(SectionPimpl); 462 } 463 464 inline uint64_t SectionRef::getIndex() const { 465 return OwningObject->getSectionIndex(SectionPimpl); 466 } 467 468 inline uint64_t SectionRef::getSize() const { 469 return OwningObject->getSectionSize(SectionPimpl); 470 } 471 472 inline Expected<StringRef> SectionRef::getContents() const { 473 Expected<ArrayRef<uint8_t>> Res = 474 OwningObject->getSectionContents(SectionPimpl); 475 if (!Res) 476 return Res.takeError(); 477 return StringRef(reinterpret_cast<const char *>(Res->data()), Res->size()); 478 } 479 480 inline uint64_t SectionRef::getAlignment() const { 481 return OwningObject->getSectionAlignment(SectionPimpl); 482 } 483 484 inline bool SectionRef::isCompressed() const { 485 return OwningObject->isSectionCompressed(SectionPimpl); 486 } 487 488 inline bool SectionRef::isText() const { 489 return OwningObject->isSectionText(SectionPimpl); 490 } 491 492 inline bool SectionRef::isData() const { 493 return OwningObject->isSectionData(SectionPimpl); 494 } 495 496 inline bool SectionRef::isBSS() const { 497 return OwningObject->isSectionBSS(SectionPimpl); 498 } 499 500 inline bool SectionRef::isVirtual() const { 501 return OwningObject->isSectionVirtual(SectionPimpl); 502 } 503 504 inline bool SectionRef::isBitcode() const { 505 return OwningObject->isSectionBitcode(SectionPimpl); 506 } 507 508 inline bool SectionRef::isStripped() const { 509 return OwningObject->isSectionStripped(SectionPimpl); 510 } 511 512 inline bool SectionRef::isBerkeleyText() const { 513 return OwningObject->isBerkeleyText(SectionPimpl); 514 } 515 516 inline bool SectionRef::isBerkeleyData() const { 517 return OwningObject->isBerkeleyData(SectionPimpl); 518 } 519 520 inline bool SectionRef::isDebugSection() const { 521 return OwningObject->isDebugSection(SectionPimpl); 522 } 523 524 inline relocation_iterator SectionRef::relocation_begin() const { 525 return OwningObject->section_rel_begin(SectionPimpl); 526 } 527 528 inline relocation_iterator SectionRef::relocation_end() const { 529 return OwningObject->section_rel_end(SectionPimpl); 530 } 531 532 inline Expected<section_iterator> SectionRef::getRelocatedSection() const { 533 return OwningObject->getRelocatedSection(SectionPimpl); 534 } 535 536 inline DataRefImpl SectionRef::getRawDataRefImpl() const { 537 return SectionPimpl; 538 } 539 540 inline const ObjectFile *SectionRef::getObject() const { 541 return OwningObject; 542 } 543 544 /// RelocationRef 545 inline RelocationRef::RelocationRef(DataRefImpl RelocationP, 546 const ObjectFile *Owner) 547 : RelocationPimpl(RelocationP) 548 , OwningObject(Owner) {} 549 550 inline bool RelocationRef::operator==(const RelocationRef &Other) const { 551 return RelocationPimpl == Other.RelocationPimpl; 552 } 553 554 inline void RelocationRef::moveNext() { 555 return OwningObject->moveRelocationNext(RelocationPimpl); 556 } 557 558 inline uint64_t RelocationRef::getOffset() const { 559 return OwningObject->getRelocationOffset(RelocationPimpl); 560 } 561 562 inline symbol_iterator RelocationRef::getSymbol() const { 563 return OwningObject->getRelocationSymbol(RelocationPimpl); 564 } 565 566 inline uint64_t RelocationRef::getType() const { 567 return OwningObject->getRelocationType(RelocationPimpl); 568 } 569 570 inline void RelocationRef::getTypeName(SmallVectorImpl<char> &Result) const { 571 return OwningObject->getRelocationTypeName(RelocationPimpl, Result); 572 } 573 574 inline DataRefImpl RelocationRef::getRawDataRefImpl() const { 575 return RelocationPimpl; 576 } 577 578 inline const ObjectFile *RelocationRef::getObject() const { 579 return OwningObject; 580 } 581 582 } // end namespace object 583 584 template <> struct DenseMapInfo<object::SectionRef> { 585 static bool isEqual(const object::SectionRef &A, 586 const object::SectionRef &B) { 587 return A == B; 588 } 589 static object::SectionRef getEmptyKey() { 590 return object::SectionRef({}, nullptr); 591 } 592 static object::SectionRef getTombstoneKey() { 593 object::DataRefImpl TS; 594 TS.p = (uintptr_t)-1; 595 return object::SectionRef(TS, nullptr); 596 } 597 static unsigned getHashValue(const object::SectionRef &Sec) { 598 object::DataRefImpl Raw = Sec.getRawDataRefImpl(); 599 return hash_combine(Raw.p, Raw.d.a, Raw.d.b); 600 } 601 }; 602 603 } // end namespace llvm 604 605 #endif // LLVM_OBJECT_OBJECTFILE_H 606