include/llvm/Object/ObjectFile.h

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