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/DenseMapInfo.h" 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/ADT/Triple.h" 19 #include "llvm/ADT/iterator_range.h" 20 #include "llvm/BinaryFormat/Magic.h" 21 #include "llvm/Object/Binary.h" 22 #include "llvm/Object/Error.h" 23 #include "llvm/Object/SymbolicFile.h" 24 #include "llvm/Support/Casting.h" 25 #include "llvm/Support/Error.h" 26 #include "llvm/Support/MemoryBuffer.h" 27 #include <cassert> 28 #include <cstdint> 29 #include <memory> 30 #include <system_error> 31 32 namespace llvm { 33 34 class ARMAttributeParser; 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_Data, 174 ST_Debug, 175 ST_File, 176 ST_Function, 177 ST_Other 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 Expected<uint64_t> getSymbolValue(DataRefImpl Symb) const; 295 296 public: 297 ObjectFile() = delete; 298 ObjectFile(const ObjectFile &other) = delete; 299 300 uint64_t getCommonSymbolSize(DataRefImpl Symb) const { 301 Expected<uint32_t> SymbolFlagsOrErr = getSymbolFlags(Symb); 302 if (!SymbolFlagsOrErr) 303 // TODO: Actually report errors helpfully. 304 report_fatal_error(SymbolFlagsOrErr.takeError()); 305 assert(*SymbolFlagsOrErr & SymbolRef::SF_Common); 306 return getCommonSymbolSizeImpl(Symb); 307 } 308 309 virtual std::vector<SectionRef> dynamic_relocation_sections() const { 310 return std::vector<SectionRef>(); 311 } 312 313 using symbol_iterator_range = iterator_range<symbol_iterator>; 314 symbol_iterator_range symbols() const { 315 return symbol_iterator_range(symbol_begin(), symbol_end()); 316 } 317 318 virtual section_iterator section_begin() const = 0; 319 virtual section_iterator section_end() const = 0; 320 321 using section_iterator_range = iterator_range<section_iterator>; 322 section_iterator_range sections() const { 323 return section_iterator_range(section_begin(), section_end()); 324 } 325 326 /// The number of bytes used to represent an address in this object 327 /// file format. 328 virtual uint8_t getBytesInAddress() const = 0; 329 330 virtual StringRef getFileFormatName() const = 0; 331 virtual Triple::ArchType getArch() const = 0; 332 virtual SubtargetFeatures getFeatures() const = 0; 333 virtual Optional<StringRef> tryGetCPUName() const { return None; }; 334 virtual void setARMSubArch(Triple &TheTriple) const { } 335 virtual Expected<uint64_t> getStartAddress() const { 336 return errorCodeToError(object_error::parse_failed); 337 }; 338 339 /// Create a triple from the data in this object file. 340 Triple makeTriple() const; 341 342 /// Maps a debug section name to a standard DWARF section name. 343 virtual StringRef mapDebugSectionName(StringRef Name) const { return Name; } 344 345 /// True if this is a relocatable object (.o/.obj). 346 virtual bool isRelocatableObject() const = 0; 347 348 /// @returns Pointer to ObjectFile subclass to handle this type of object. 349 /// @param ObjectPath The path to the object file. ObjectPath.isObject must 350 /// return true. 351 /// Create ObjectFile from path. 352 static Expected<OwningBinary<ObjectFile>> 353 createObjectFile(StringRef ObjectPath); 354 355 static Expected<std::unique_ptr<ObjectFile>> 356 createObjectFile(MemoryBufferRef Object, llvm::file_magic Type, 357 bool InitContent = true); 358 static Expected<std::unique_ptr<ObjectFile>> 359 createObjectFile(MemoryBufferRef Object) { 360 return createObjectFile(Object, llvm::file_magic::unknown); 361 } 362 363 static bool classof(const Binary *v) { 364 return v->isObject(); 365 } 366 367 static Expected<std::unique_ptr<COFFObjectFile>> 368 createCOFFObjectFile(MemoryBufferRef Object); 369 370 static Expected<std::unique_ptr<ObjectFile>> 371 createXCOFFObjectFile(MemoryBufferRef Object, unsigned FileType); 372 373 static Expected<std::unique_ptr<ObjectFile>> 374 createELFObjectFile(MemoryBufferRef Object, bool InitContent = true); 375 376 static Expected<std::unique_ptr<MachOObjectFile>> 377 createMachOObjectFile(MemoryBufferRef Object, 378 uint32_t UniversalCputype = 0, 379 uint32_t UniversalIndex = 0); 380 381 static Expected<std::unique_ptr<WasmObjectFile>> 382 createWasmObjectFile(MemoryBufferRef Object); 383 }; 384 385 // Inline function definitions. 386 inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner) 387 : BasicSymbolRef(SymbolP, Owner) {} 388 389 inline Expected<StringRef> SymbolRef::getName() const { 390 return getObject()->getSymbolName(getRawDataRefImpl()); 391 } 392 393 inline Expected<uint64_t> SymbolRef::getAddress() const { 394 return getObject()->getSymbolAddress(getRawDataRefImpl()); 395 } 396 397 inline Expected<uint64_t> SymbolRef::getValue() const { 398 return getObject()->getSymbolValue(getRawDataRefImpl()); 399 } 400 401 inline uint32_t SymbolRef::getAlignment() const { 402 return getObject()->getSymbolAlignment(getRawDataRefImpl()); 403 } 404 405 inline uint64_t SymbolRef::getCommonSize() const { 406 return getObject()->getCommonSymbolSize(getRawDataRefImpl()); 407 } 408 409 inline Expected<section_iterator> SymbolRef::getSection() const { 410 return getObject()->getSymbolSection(getRawDataRefImpl()); 411 } 412 413 inline Expected<SymbolRef::Type> SymbolRef::getType() const { 414 return getObject()->getSymbolType(getRawDataRefImpl()); 415 } 416 417 inline const ObjectFile *SymbolRef::getObject() const { 418 const SymbolicFile *O = BasicSymbolRef::getObject(); 419 return cast<ObjectFile>(O); 420 } 421 422 /// SectionRef 423 inline SectionRef::SectionRef(DataRefImpl SectionP, 424 const ObjectFile *Owner) 425 : SectionPimpl(SectionP) 426 , OwningObject(Owner) {} 427 428 inline bool SectionRef::operator==(const SectionRef &Other) const { 429 return OwningObject == Other.OwningObject && 430 SectionPimpl == Other.SectionPimpl; 431 } 432 433 inline bool SectionRef::operator!=(const SectionRef &Other) const { 434 return !(*this == Other); 435 } 436 437 inline bool SectionRef::operator<(const SectionRef &Other) const { 438 assert(OwningObject == Other.OwningObject); 439 return SectionPimpl < Other.SectionPimpl; 440 } 441 442 inline void SectionRef::moveNext() { 443 return OwningObject->moveSectionNext(SectionPimpl); 444 } 445 446 inline Expected<StringRef> SectionRef::getName() const { 447 return OwningObject->getSectionName(SectionPimpl); 448 } 449 450 inline uint64_t SectionRef::getAddress() const { 451 return OwningObject->getSectionAddress(SectionPimpl); 452 } 453 454 inline uint64_t SectionRef::getIndex() const { 455 return OwningObject->getSectionIndex(SectionPimpl); 456 } 457 458 inline uint64_t SectionRef::getSize() const { 459 return OwningObject->getSectionSize(SectionPimpl); 460 } 461 462 inline Expected<StringRef> SectionRef::getContents() const { 463 Expected<ArrayRef<uint8_t>> Res = 464 OwningObject->getSectionContents(SectionPimpl); 465 if (!Res) 466 return Res.takeError(); 467 return StringRef(reinterpret_cast<const char *>(Res->data()), Res->size()); 468 } 469 470 inline uint64_t SectionRef::getAlignment() const { 471 return OwningObject->getSectionAlignment(SectionPimpl); 472 } 473 474 inline bool SectionRef::isCompressed() const { 475 return OwningObject->isSectionCompressed(SectionPimpl); 476 } 477 478 inline bool SectionRef::isText() const { 479 return OwningObject->isSectionText(SectionPimpl); 480 } 481 482 inline bool SectionRef::isData() const { 483 return OwningObject->isSectionData(SectionPimpl); 484 } 485 486 inline bool SectionRef::isBSS() const { 487 return OwningObject->isSectionBSS(SectionPimpl); 488 } 489 490 inline bool SectionRef::isVirtual() const { 491 return OwningObject->isSectionVirtual(SectionPimpl); 492 } 493 494 inline bool SectionRef::isBitcode() const { 495 return OwningObject->isSectionBitcode(SectionPimpl); 496 } 497 498 inline bool SectionRef::isStripped() const { 499 return OwningObject->isSectionStripped(SectionPimpl); 500 } 501 502 inline bool SectionRef::isBerkeleyText() const { 503 return OwningObject->isBerkeleyText(SectionPimpl); 504 } 505 506 inline bool SectionRef::isBerkeleyData() const { 507 return OwningObject->isBerkeleyData(SectionPimpl); 508 } 509 510 inline bool SectionRef::isDebugSection() const { 511 return OwningObject->isDebugSection(SectionPimpl); 512 } 513 514 inline relocation_iterator SectionRef::relocation_begin() const { 515 return OwningObject->section_rel_begin(SectionPimpl); 516 } 517 518 inline relocation_iterator SectionRef::relocation_end() const { 519 return OwningObject->section_rel_end(SectionPimpl); 520 } 521 522 inline Expected<section_iterator> SectionRef::getRelocatedSection() const { 523 return OwningObject->getRelocatedSection(SectionPimpl); 524 } 525 526 inline DataRefImpl SectionRef::getRawDataRefImpl() const { 527 return SectionPimpl; 528 } 529 530 inline const ObjectFile *SectionRef::getObject() const { 531 return OwningObject; 532 } 533 534 /// RelocationRef 535 inline RelocationRef::RelocationRef(DataRefImpl RelocationP, 536 const ObjectFile *Owner) 537 : RelocationPimpl(RelocationP) 538 , OwningObject(Owner) {} 539 540 inline bool RelocationRef::operator==(const RelocationRef &Other) const { 541 return RelocationPimpl == Other.RelocationPimpl; 542 } 543 544 inline void RelocationRef::moveNext() { 545 return OwningObject->moveRelocationNext(RelocationPimpl); 546 } 547 548 inline uint64_t RelocationRef::getOffset() const { 549 return OwningObject->getRelocationOffset(RelocationPimpl); 550 } 551 552 inline symbol_iterator RelocationRef::getSymbol() const { 553 return OwningObject->getRelocationSymbol(RelocationPimpl); 554 } 555 556 inline uint64_t RelocationRef::getType() const { 557 return OwningObject->getRelocationType(RelocationPimpl); 558 } 559 560 inline void RelocationRef::getTypeName(SmallVectorImpl<char> &Result) const { 561 return OwningObject->getRelocationTypeName(RelocationPimpl, Result); 562 } 563 564 inline DataRefImpl RelocationRef::getRawDataRefImpl() const { 565 return RelocationPimpl; 566 } 567 568 inline const ObjectFile *RelocationRef::getObject() const { 569 return OwningObject; 570 } 571 572 } // end namespace object 573 574 template <> struct DenseMapInfo<object::SectionRef> { 575 static bool isEqual(const object::SectionRef &A, 576 const object::SectionRef &B) { 577 return A == B; 578 } 579 static object::SectionRef getEmptyKey() { 580 return object::SectionRef({}, nullptr); 581 } 582 static object::SectionRef getTombstoneKey() { 583 object::DataRefImpl TS; 584 TS.p = (uintptr_t)-1; 585 return object::SectionRef(TS, nullptr); 586 } 587 static unsigned getHashValue(const object::SectionRef &Sec) { 588 object::DataRefImpl Raw = Sec.getRawDataRefImpl(); 589 return hash_combine(Raw.p, Raw.d.a, Raw.d.b); 590 } 591 }; 592 593 } // end namespace llvm 594 595 #endif // LLVM_OBJECT_OBJECTFILE_H 596