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(StringRef SectionName) 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 Expected<section_iterator> getRelocatedSection() const; 136 137 DataRefImpl getRawDataRefImpl() const; 138 const ObjectFile *getObject() const; 139 }; 140 141 struct SectionedAddress { 142 const static uint64_t UndefSection = UINT64_MAX; 143 144 uint64_t Address = 0; 145 uint64_t SectionIndex = UndefSection; 146 }; 147 148 inline bool operator<(const SectionedAddress &LHS, 149 const SectionedAddress &RHS) { 150 return std::tie(LHS.SectionIndex, LHS.Address) < 151 std::tie(RHS.SectionIndex, RHS.Address); 152 } 153 154 inline bool operator==(const SectionedAddress &LHS, 155 const SectionedAddress &RHS) { 156 return std::tie(LHS.SectionIndex, LHS.Address) == 157 std::tie(RHS.SectionIndex, RHS.Address); 158 } 159 160 raw_ostream &operator<<(raw_ostream &OS, const SectionedAddress &Addr); 161 162 /// This is a value type class that represents a single symbol in the list of 163 /// symbols in the object file. 164 class SymbolRef : public BasicSymbolRef { 165 friend class SectionRef; 166 167 public: 168 enum Type { 169 ST_Unknown, // Type not specified 170 ST_Data, 171 ST_Debug, 172 ST_File, 173 ST_Function, 174 ST_Other 175 }; 176 177 SymbolRef() = default; 178 SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner); 179 SymbolRef(const BasicSymbolRef &B) : BasicSymbolRef(B) { 180 assert(isa<ObjectFile>(BasicSymbolRef::getObject())); 181 } 182 183 Expected<StringRef> getName() const; 184 /// Returns the symbol virtual address (i.e. address at which it will be 185 /// mapped). 186 Expected<uint64_t> getAddress() const; 187 188 /// Return the value of the symbol depending on the object this can be an 189 /// offset or a virtual address. 190 Expected<uint64_t> getValue() const; 191 192 /// Get the alignment of this symbol as the actual value (not log 2). 193 uint32_t getAlignment() const; 194 uint64_t getCommonSize() const; 195 Expected<SymbolRef::Type> getType() const; 196 197 /// Get section this symbol is defined in reference to. Result is 198 /// end_sections() if it is undefined or is an absolute symbol. 199 Expected<section_iterator> getSection() const; 200 201 const ObjectFile *getObject() const; 202 }; 203 204 class symbol_iterator : public basic_symbol_iterator { 205 public: 206 symbol_iterator(SymbolRef Sym) : basic_symbol_iterator(Sym) {} 207 symbol_iterator(const basic_symbol_iterator &B) 208 : basic_symbol_iterator(SymbolRef(B->getRawDataRefImpl(), 209 cast<ObjectFile>(B->getObject()))) {} 210 211 const SymbolRef *operator->() const { 212 const BasicSymbolRef &P = basic_symbol_iterator::operator *(); 213 return static_cast<const SymbolRef*>(&P); 214 } 215 216 const SymbolRef &operator*() const { 217 const BasicSymbolRef &P = basic_symbol_iterator::operator *(); 218 return static_cast<const SymbolRef&>(P); 219 } 220 }; 221 222 /// This class is the base class for all object file types. Concrete instances 223 /// of this object are created by createObjectFile, which figures out which type 224 /// to create. 225 class ObjectFile : public SymbolicFile { 226 virtual void anchor(); 227 228 protected: 229 ObjectFile(unsigned int Type, MemoryBufferRef Source); 230 231 const uint8_t *base() const { 232 return reinterpret_cast<const uint8_t *>(Data.getBufferStart()); 233 } 234 235 // These functions are for SymbolRef to call internally. The main goal of 236 // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol 237 // entry in the memory mapped object file. SymbolPimpl cannot contain any 238 // virtual functions because then it could not point into the memory mapped 239 // file. 240 // 241 // Implementations assume that the DataRefImpl is valid and has not been 242 // modified externally. It's UB otherwise. 243 friend class SymbolRef; 244 245 virtual Expected<StringRef> getSymbolName(DataRefImpl Symb) const = 0; 246 Error printSymbolName(raw_ostream &OS, 247 DataRefImpl Symb) const override; 248 virtual Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const = 0; 249 virtual uint64_t getSymbolValueImpl(DataRefImpl Symb) const = 0; 250 virtual uint32_t getSymbolAlignment(DataRefImpl Symb) const; 251 virtual uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const = 0; 252 virtual Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const = 0; 253 virtual Expected<section_iterator> 254 getSymbolSection(DataRefImpl Symb) const = 0; 255 256 // Same as above for SectionRef. 257 friend class SectionRef; 258 259 virtual void moveSectionNext(DataRefImpl &Sec) const = 0; 260 virtual Expected<StringRef> getSectionName(DataRefImpl Sec) const = 0; 261 virtual uint64_t getSectionAddress(DataRefImpl Sec) const = 0; 262 virtual uint64_t getSectionIndex(DataRefImpl Sec) const = 0; 263 virtual uint64_t getSectionSize(DataRefImpl Sec) const = 0; 264 virtual Expected<ArrayRef<uint8_t>> 265 getSectionContents(DataRefImpl Sec) const = 0; 266 virtual uint64_t getSectionAlignment(DataRefImpl Sec) const = 0; 267 virtual bool isSectionCompressed(DataRefImpl Sec) const = 0; 268 virtual bool isSectionText(DataRefImpl Sec) const = 0; 269 virtual bool isSectionData(DataRefImpl Sec) const = 0; 270 virtual bool isSectionBSS(DataRefImpl Sec) const = 0; 271 // A section is 'virtual' if its contents aren't present in the object image. 272 virtual bool isSectionVirtual(DataRefImpl Sec) const = 0; 273 virtual bool isSectionBitcode(DataRefImpl Sec) const; 274 virtual bool isSectionStripped(DataRefImpl Sec) const; 275 virtual bool isBerkeleyText(DataRefImpl Sec) const; 276 virtual bool isBerkeleyData(DataRefImpl Sec) const; 277 virtual bool isDebugSection(StringRef SectionName) const; 278 virtual relocation_iterator section_rel_begin(DataRefImpl Sec) const = 0; 279 virtual relocation_iterator section_rel_end(DataRefImpl Sec) const = 0; 280 virtual Expected<section_iterator> getRelocatedSection(DataRefImpl Sec) const; 281 282 // Same as above for RelocationRef. 283 friend class RelocationRef; 284 virtual void moveRelocationNext(DataRefImpl &Rel) const = 0; 285 virtual uint64_t getRelocationOffset(DataRefImpl Rel) const = 0; 286 virtual symbol_iterator getRelocationSymbol(DataRefImpl Rel) const = 0; 287 virtual uint64_t getRelocationType(DataRefImpl Rel) const = 0; 288 virtual void getRelocationTypeName(DataRefImpl Rel, 289 SmallVectorImpl<char> &Result) const = 0; 290 291 Expected<uint64_t> getSymbolValue(DataRefImpl Symb) const; 292 293 public: 294 ObjectFile() = delete; 295 ObjectFile(const ObjectFile &other) = delete; 296 297 uint64_t getCommonSymbolSize(DataRefImpl Symb) const { 298 Expected<uint32_t> SymbolFlagsOrErr = getSymbolFlags(Symb); 299 if (!SymbolFlagsOrErr) 300 // TODO: Actually report errors helpfully. 301 report_fatal_error(SymbolFlagsOrErr.takeError()); 302 assert(*SymbolFlagsOrErr & SymbolRef::SF_Common); 303 return getCommonSymbolSizeImpl(Symb); 304 } 305 306 virtual std::vector<SectionRef> dynamic_relocation_sections() const { 307 return std::vector<SectionRef>(); 308 } 309 310 using symbol_iterator_range = iterator_range<symbol_iterator>; 311 symbol_iterator_range symbols() const { 312 return symbol_iterator_range(symbol_begin(), symbol_end()); 313 } 314 315 virtual section_iterator section_begin() const = 0; 316 virtual section_iterator section_end() const = 0; 317 318 using section_iterator_range = iterator_range<section_iterator>; 319 section_iterator_range sections() const { 320 return section_iterator_range(section_begin(), section_end()); 321 } 322 323 /// The number of bytes used to represent an address in this object 324 /// file format. 325 virtual uint8_t getBytesInAddress() const = 0; 326 327 virtual StringRef getFileFormatName() const = 0; 328 virtual Triple::ArchType getArch() const = 0; 329 virtual SubtargetFeatures getFeatures() const = 0; 330 virtual Optional<StringRef> tryGetCPUName() const { return None; }; 331 virtual void setARMSubArch(Triple &TheTriple) const { } 332 virtual Expected<uint64_t> getStartAddress() const { 333 return errorCodeToError(object_error::parse_failed); 334 }; 335 336 /// Create a triple from the data in this object file. 337 Triple makeTriple() const; 338 339 /// Maps a debug section name to a standard DWARF section name. 340 virtual StringRef mapDebugSectionName(StringRef Name) const { return Name; } 341 342 /// True if this is a relocatable object (.o/.obj). 343 virtual bool isRelocatableObject() const = 0; 344 345 /// @returns Pointer to ObjectFile subclass to handle this type of object. 346 /// @param ObjectPath The path to the object file. ObjectPath.isObject must 347 /// return true. 348 /// Create ObjectFile from path. 349 static Expected<OwningBinary<ObjectFile>> 350 createObjectFile(StringRef ObjectPath); 351 352 static Expected<std::unique_ptr<ObjectFile>> 353 createObjectFile(MemoryBufferRef Object, llvm::file_magic Type, 354 bool InitContent = true); 355 static Expected<std::unique_ptr<ObjectFile>> 356 createObjectFile(MemoryBufferRef Object) { 357 return createObjectFile(Object, llvm::file_magic::unknown); 358 } 359 360 static bool classof(const Binary *v) { 361 return v->isObject(); 362 } 363 364 static Expected<std::unique_ptr<COFFObjectFile>> 365 createCOFFObjectFile(MemoryBufferRef Object); 366 367 static Expected<std::unique_ptr<ObjectFile>> 368 createXCOFFObjectFile(MemoryBufferRef Object, unsigned FileType); 369 370 static Expected<std::unique_ptr<ObjectFile>> 371 createELFObjectFile(MemoryBufferRef Object, bool InitContent = true); 372 373 static Expected<std::unique_ptr<MachOObjectFile>> 374 createMachOObjectFile(MemoryBufferRef Object, 375 uint32_t UniversalCputype = 0, 376 uint32_t UniversalIndex = 0); 377 378 static Expected<std::unique_ptr<WasmObjectFile>> 379 createWasmObjectFile(MemoryBufferRef Object); 380 }; 381 382 // Inline function definitions. 383 inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner) 384 : BasicSymbolRef(SymbolP, Owner) {} 385 386 inline Expected<StringRef> SymbolRef::getName() const { 387 return getObject()->getSymbolName(getRawDataRefImpl()); 388 } 389 390 inline Expected<uint64_t> SymbolRef::getAddress() const { 391 return getObject()->getSymbolAddress(getRawDataRefImpl()); 392 } 393 394 inline Expected<uint64_t> SymbolRef::getValue() const { 395 return getObject()->getSymbolValue(getRawDataRefImpl()); 396 } 397 398 inline uint32_t SymbolRef::getAlignment() const { 399 return getObject()->getSymbolAlignment(getRawDataRefImpl()); 400 } 401 402 inline uint64_t SymbolRef::getCommonSize() const { 403 return getObject()->getCommonSymbolSize(getRawDataRefImpl()); 404 } 405 406 inline Expected<section_iterator> SymbolRef::getSection() const { 407 return getObject()->getSymbolSection(getRawDataRefImpl()); 408 } 409 410 inline Expected<SymbolRef::Type> SymbolRef::getType() const { 411 return getObject()->getSymbolType(getRawDataRefImpl()); 412 } 413 414 inline const ObjectFile *SymbolRef::getObject() const { 415 const SymbolicFile *O = BasicSymbolRef::getObject(); 416 return cast<ObjectFile>(O); 417 } 418 419 /// SectionRef 420 inline SectionRef::SectionRef(DataRefImpl SectionP, 421 const ObjectFile *Owner) 422 : SectionPimpl(SectionP) 423 , OwningObject(Owner) {} 424 425 inline bool SectionRef::operator==(const SectionRef &Other) const { 426 return OwningObject == Other.OwningObject && 427 SectionPimpl == Other.SectionPimpl; 428 } 429 430 inline bool SectionRef::operator!=(const SectionRef &Other) const { 431 return !(*this == Other); 432 } 433 434 inline bool SectionRef::operator<(const SectionRef &Other) const { 435 assert(OwningObject == Other.OwningObject); 436 return SectionPimpl < Other.SectionPimpl; 437 } 438 439 inline void SectionRef::moveNext() { 440 return OwningObject->moveSectionNext(SectionPimpl); 441 } 442 443 inline Expected<StringRef> SectionRef::getName() const { 444 return OwningObject->getSectionName(SectionPimpl); 445 } 446 447 inline uint64_t SectionRef::getAddress() const { 448 return OwningObject->getSectionAddress(SectionPimpl); 449 } 450 451 inline uint64_t SectionRef::getIndex() const { 452 return OwningObject->getSectionIndex(SectionPimpl); 453 } 454 455 inline uint64_t SectionRef::getSize() const { 456 return OwningObject->getSectionSize(SectionPimpl); 457 } 458 459 inline Expected<StringRef> SectionRef::getContents() const { 460 Expected<ArrayRef<uint8_t>> Res = 461 OwningObject->getSectionContents(SectionPimpl); 462 if (!Res) 463 return Res.takeError(); 464 return StringRef(reinterpret_cast<const char *>(Res->data()), Res->size()); 465 } 466 467 inline uint64_t SectionRef::getAlignment() const { 468 return OwningObject->getSectionAlignment(SectionPimpl); 469 } 470 471 inline bool SectionRef::isCompressed() const { 472 return OwningObject->isSectionCompressed(SectionPimpl); 473 } 474 475 inline bool SectionRef::isText() const { 476 return OwningObject->isSectionText(SectionPimpl); 477 } 478 479 inline bool SectionRef::isData() const { 480 return OwningObject->isSectionData(SectionPimpl); 481 } 482 483 inline bool SectionRef::isBSS() const { 484 return OwningObject->isSectionBSS(SectionPimpl); 485 } 486 487 inline bool SectionRef::isVirtual() const { 488 return OwningObject->isSectionVirtual(SectionPimpl); 489 } 490 491 inline bool SectionRef::isBitcode() const { 492 return OwningObject->isSectionBitcode(SectionPimpl); 493 } 494 495 inline bool SectionRef::isStripped() const { 496 return OwningObject->isSectionStripped(SectionPimpl); 497 } 498 499 inline bool SectionRef::isBerkeleyText() const { 500 return OwningObject->isBerkeleyText(SectionPimpl); 501 } 502 503 inline bool SectionRef::isBerkeleyData() const { 504 return OwningObject->isBerkeleyData(SectionPimpl); 505 } 506 507 inline bool SectionRef::isDebugSection(StringRef SectionName) const { 508 return OwningObject->isDebugSection(SectionName); 509 } 510 511 inline relocation_iterator SectionRef::relocation_begin() const { 512 return OwningObject->section_rel_begin(SectionPimpl); 513 } 514 515 inline relocation_iterator SectionRef::relocation_end() const { 516 return OwningObject->section_rel_end(SectionPimpl); 517 } 518 519 inline Expected<section_iterator> SectionRef::getRelocatedSection() const { 520 return OwningObject->getRelocatedSection(SectionPimpl); 521 } 522 523 inline DataRefImpl SectionRef::getRawDataRefImpl() const { 524 return SectionPimpl; 525 } 526 527 inline const ObjectFile *SectionRef::getObject() const { 528 return OwningObject; 529 } 530 531 /// RelocationRef 532 inline RelocationRef::RelocationRef(DataRefImpl RelocationP, 533 const ObjectFile *Owner) 534 : RelocationPimpl(RelocationP) 535 , OwningObject(Owner) {} 536 537 inline bool RelocationRef::operator==(const RelocationRef &Other) const { 538 return RelocationPimpl == Other.RelocationPimpl; 539 } 540 541 inline void RelocationRef::moveNext() { 542 return OwningObject->moveRelocationNext(RelocationPimpl); 543 } 544 545 inline uint64_t RelocationRef::getOffset() const { 546 return OwningObject->getRelocationOffset(RelocationPimpl); 547 } 548 549 inline symbol_iterator RelocationRef::getSymbol() const { 550 return OwningObject->getRelocationSymbol(RelocationPimpl); 551 } 552 553 inline uint64_t RelocationRef::getType() const { 554 return OwningObject->getRelocationType(RelocationPimpl); 555 } 556 557 inline void RelocationRef::getTypeName(SmallVectorImpl<char> &Result) const { 558 return OwningObject->getRelocationTypeName(RelocationPimpl, Result); 559 } 560 561 inline DataRefImpl RelocationRef::getRawDataRefImpl() const { 562 return RelocationPimpl; 563 } 564 565 inline const ObjectFile *RelocationRef::getObject() const { 566 return OwningObject; 567 } 568 569 } // end namespace object 570 571 template <> struct DenseMapInfo<object::SectionRef> { 572 static bool isEqual(const object::SectionRef &A, 573 const object::SectionRef &B) { 574 return A == B; 575 } 576 static object::SectionRef getEmptyKey() { 577 return object::SectionRef({}, nullptr); 578 } 579 static object::SectionRef getTombstoneKey() { 580 object::DataRefImpl TS; 581 TS.p = (uintptr_t)-1; 582 return object::SectionRef(TS, nullptr); 583 } 584 static unsigned getHashValue(const object::SectionRef &Sec) { 585 object::DataRefImpl Raw = Sec.getRawDataRefImpl(); 586 return hash_combine(Raw.p, Raw.d.a, Raw.d.b); 587 } 588 }; 589 590 } // end namespace llvm 591 592 #endif // LLVM_OBJECT_OBJECTFILE_H 593