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   // TODO: constructors could be removed when C++14 would be adopted.
 141   SectionedAddress() {}
 142   SectionedAddress(uint64_t Addr, uint64_t SectIdx)
 143       : Address(Addr), SectionIndex(SectIdx) {}
 144
 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 /// This is a value type class that represents a single symbol in the list of
 164 /// symbols in the object file.
 165 class SymbolRef : public BasicSymbolRef {
 166   friend class SectionRef;
 167
 168 public:
 169   enum Type {
 170     ST_Unknown, // Type not specified
 171     ST_Data,
 172     ST_Debug,
 173     ST_File,
 174     ST_Function,
 175     ST_Other
 176   };
 177
 178   SymbolRef() = default;
 179   SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
 180   SymbolRef(const BasicSymbolRef &B) : BasicSymbolRef(B) {
 181     assert(isa<ObjectFile>(BasicSymbolRef::getObject()));
 182   }
 183
 184   Expected<StringRef> getName() const;
 185   /// Returns the symbol virtual address (i.e. address at which it will be
 186   /// mapped).
 187   Expected<uint64_t> getAddress() const;
 188
 189   /// Return the value of the symbol depending on the object this can be an
 190   /// offset or a virtual address.
 191   uint64_t getValue() const;
 192
 193   /// Get the alignment of this symbol as the actual value (not log 2).
 194   uint32_t getAlignment() const;
 195   uint64_t getCommonSize() const;
 196   Expected<SymbolRef::Type> getType() const;
 197
 198   /// Get section this symbol is defined in reference to. Result is
 199   /// end_sections() if it is undefined or is an absolute symbol.
 200   Expected<section_iterator> getSection() const;
 201
 202   const ObjectFile *getObject() const;
 203 };
 204
 205 class symbol_iterator : public basic_symbol_iterator {
 206 public:
 207   symbol_iterator(SymbolRef Sym) : basic_symbol_iterator(Sym) {}
 208   symbol_iterator(const basic_symbol_iterator &B)
 209       : basic_symbol_iterator(SymbolRef(B->getRawDataRefImpl(),
 210                                         cast<ObjectFile>(B->getObject()))) {}
 211
 212   const SymbolRef *operator->() const {
 213     const BasicSymbolRef &P = basic_symbol_iterator::operator *();
 214     return static_cast<const SymbolRef*>(&P);
 215   }
 216
 217   const SymbolRef &operator*() const {
 218     const BasicSymbolRef &P = basic_symbol_iterator::operator *();
 219     return static_cast<const SymbolRef&>(P);
 220   }
 221 };
 222
 223 /// This class is the base class for all object file types. Concrete instances
 224 /// of this object are created by createObjectFile, which figures out which type
 225 /// to create.
 226 class ObjectFile : public SymbolicFile {
 227   virtual void anchor();
 228
 229 protected:
 230   ObjectFile(unsigned int Type, MemoryBufferRef Source);
 231
 232   const uint8_t *base() const {
 233     return reinterpret_cast<const uint8_t *>(Data.getBufferStart());
 234   }
 235
 236   // These functions are for SymbolRef to call internally. The main goal of
 237   // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
 238   // entry in the memory mapped object file. SymbolPimpl cannot contain any
 239   // virtual functions because then it could not point into the memory mapped
 240   // file.
 241   //
 242   // Implementations assume that the DataRefImpl is valid and has not been
 243   // modified externally. It's UB otherwise.
 244   friend class SymbolRef;
 245
 246   virtual Expected<StringRef> getSymbolName(DataRefImpl Symb) const = 0;
 247   Error printSymbolName(raw_ostream &OS,
 248                                   DataRefImpl Symb) const override;
 249   virtual Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const = 0;
 250   virtual uint64_t getSymbolValueImpl(DataRefImpl Symb) const = 0;
 251   virtual uint32_t getSymbolAlignment(DataRefImpl Symb) const;
 252   virtual uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const = 0;
 253   virtual Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const = 0;
 254   virtual Expected<section_iterator>
 255   getSymbolSection(DataRefImpl Symb) const = 0;
 256
 257   // Same as above for SectionRef.
 258   friend class SectionRef;
 259
 260   virtual void moveSectionNext(DataRefImpl &Sec) const = 0;
 261   virtual Expected<StringRef> getSectionName(DataRefImpl Sec) const = 0;
 262   virtual uint64_t getSectionAddress(DataRefImpl Sec) const = 0;
 263   virtual uint64_t getSectionIndex(DataRefImpl Sec) const = 0;
 264   virtual uint64_t getSectionSize(DataRefImpl Sec) const = 0;
 265   virtual Expected<ArrayRef<uint8_t>>
 266   getSectionContents(DataRefImpl Sec) const = 0;
 267   virtual uint64_t getSectionAlignment(DataRefImpl Sec) const = 0;
 268   virtual bool isSectionCompressed(DataRefImpl Sec) const = 0;
 269   virtual bool isSectionText(DataRefImpl Sec) const = 0;
 270   virtual bool isSectionData(DataRefImpl Sec) const = 0;
 271   virtual bool isSectionBSS(DataRefImpl Sec) const = 0;
 272   // A section is 'virtual' if its contents aren't present in the object image.
 273   virtual bool isSectionVirtual(DataRefImpl Sec) const = 0;
 274   virtual bool isSectionBitcode(DataRefImpl Sec) const;
 275   virtual bool isSectionStripped(DataRefImpl Sec) const;
 276   virtual bool isBerkeleyText(DataRefImpl Sec) const;
 277   virtual bool isBerkeleyData(DataRefImpl Sec) 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 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   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     assert(getSymbolFlags(Symb) & SymbolRef::SF_Common);
 299     return getCommonSymbolSizeImpl(Symb);
 300   }
 301
 302   virtual std::vector<SectionRef> dynamic_relocation_sections() const {
 303     return std::vector<SectionRef>();
 304   }
 305
 306   using symbol_iterator_range = iterator_range<symbol_iterator>;
 307   symbol_iterator_range symbols() const {
 308     return symbol_iterator_range(symbol_begin(), symbol_end());
 309   }
 310
 311   virtual section_iterator section_begin() const = 0;
 312   virtual section_iterator section_end() const = 0;
 313
 314   using section_iterator_range = iterator_range<section_iterator>;
 315   section_iterator_range sections() const {
 316     return section_iterator_range(section_begin(), section_end());
 317   }
 318
 319   /// The number of bytes used to represent an address in this object
 320   ///        file format.
 321   virtual uint8_t getBytesInAddress() const = 0;
 322
 323   virtual StringRef getFileFormatName() const = 0;
 324   virtual Triple::ArchType getArch() const = 0;
 325   virtual SubtargetFeatures getFeatures() const = 0;
 326   virtual void setARMSubArch(Triple &TheTriple) const { }
 327   virtual Expected<uint64_t> getStartAddress() const {
 328     return errorCodeToError(object_error::parse_failed);
 329   };
 330
 331   /// Create a triple from the data in this object file.
 332   Triple makeTriple() const;
 333
 334   /// Maps a debug section name to a standard DWARF section name.
 335   virtual StringRef mapDebugSectionName(StringRef Name) const { return Name; }
 336
 337   /// True if this is a relocatable object (.o/.obj).
 338   virtual bool isRelocatableObject() const = 0;
 339
 340   /// @returns Pointer to ObjectFile subclass to handle this type of object.
 341   /// @param ObjectPath The path to the object file. ObjectPath.isObject must
 342   ///        return true.
 343   /// Create ObjectFile from path.
 344   static Expected<OwningBinary<ObjectFile>>
 345   createObjectFile(StringRef ObjectPath);
 346
 347   static Expected<std::unique_ptr<ObjectFile>>
 348   createObjectFile(MemoryBufferRef Object, llvm::file_magic Type);
 349   static Expected<std::unique_ptr<ObjectFile>>
 350   createObjectFile(MemoryBufferRef Object) {
 351     return createObjectFile(Object, llvm::file_magic::unknown);
 352   }
 353
 354   static bool classof(const Binary *v) {
 355     return v->isObject();
 356   }
 357
 358   static Expected<std::unique_ptr<COFFObjectFile>>
 359   createCOFFObjectFile(MemoryBufferRef Object);
 360
 361   static Expected<std::unique_ptr<ObjectFile>>
 362   createXCOFFObjectFile(MemoryBufferRef Object, unsigned FileType);
 363
 364   static Expected<std::unique_ptr<ObjectFile>>
 365   createELFObjectFile(MemoryBufferRef Object);
 366
 367   static Expected<std::unique_ptr<MachOObjectFile>>
 368   createMachOObjectFile(MemoryBufferRef Object,
 369                         uint32_t UniversalCputype = 0,
 370                         uint32_t UniversalIndex = 0);
 371
 372   static Expected<std::unique_ptr<WasmObjectFile>>
 373   createWasmObjectFile(MemoryBufferRef Object);
 374 };
 375
 376 // Inline function definitions.
 377 inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
 378     : BasicSymbolRef(SymbolP, Owner) {}
 379
 380 inline Expected<StringRef> SymbolRef::getName() const {
 381   return getObject()->getSymbolName(getRawDataRefImpl());
 382 }
 383
 384 inline Expected<uint64_t> SymbolRef::getAddress() const {
 385   return getObject()->getSymbolAddress(getRawDataRefImpl());
 386 }
 387
 388 inline uint64_t SymbolRef::getValue() const {
 389   return getObject()->getSymbolValue(getRawDataRefImpl());
 390 }
 391
 392 inline uint32_t SymbolRef::getAlignment() const {
 393   return getObject()->getSymbolAlignment(getRawDataRefImpl());
 394 }
 395
 396 inline uint64_t SymbolRef::getCommonSize() const {
 397   return getObject()->getCommonSymbolSize(getRawDataRefImpl());
 398 }
 399
 400 inline Expected<section_iterator> SymbolRef::getSection() const {
 401   return getObject()->getSymbolSection(getRawDataRefImpl());
 402 }
 403
 404 inline Expected<SymbolRef::Type> SymbolRef::getType() const {
 405   return getObject()->getSymbolType(getRawDataRefImpl());
 406 }
 407
 408 inline const ObjectFile *SymbolRef::getObject() const {
 409   const SymbolicFile *O = BasicSymbolRef::getObject();
 410   return cast<ObjectFile>(O);
 411 }
 412
 413 /// SectionRef
 414 inline SectionRef::SectionRef(DataRefImpl SectionP,
 415                               const ObjectFile *Owner)
 416   : SectionPimpl(SectionP)
 417   , OwningObject(Owner) {}
 418
 419 inline bool SectionRef::operator==(const SectionRef &Other) const {
 420   return OwningObject == Other.OwningObject &&
 421          SectionPimpl == Other.SectionPimpl;
 422 }
 423
 424 inline bool SectionRef::operator!=(const SectionRef &Other) const {
 425   return !(*this == Other);
 426 }
 427
 428 inline bool SectionRef::operator<(const SectionRef &Other) const {
 429   assert(OwningObject == Other.OwningObject);
 430   return SectionPimpl < Other.SectionPimpl;
 431 }
 432
 433 inline void SectionRef::moveNext() {
 434   return OwningObject->moveSectionNext(SectionPimpl);
 435 }
 436
 437 inline Expected<StringRef> SectionRef::getName() const {
 438   return OwningObject->getSectionName(SectionPimpl);
 439 }
 440
 441 inline uint64_t SectionRef::getAddress() const {
 442   return OwningObject->getSectionAddress(SectionPimpl);
 443 }
 444
 445 inline uint64_t SectionRef::getIndex() const {
 446   return OwningObject->getSectionIndex(SectionPimpl);
 447 }
 448
 449 inline uint64_t SectionRef::getSize() const {
 450   return OwningObject->getSectionSize(SectionPimpl);
 451 }
 452
 453 inline Expected<StringRef> SectionRef::getContents() const {
 454   Expected<ArrayRef<uint8_t>> Res =
 455       OwningObject->getSectionContents(SectionPimpl);
 456   if (!Res)
 457     return Res.takeError();
 458   return StringRef(reinterpret_cast<const char *>(Res->data()), Res->size());
 459 }
 460
 461 inline uint64_t SectionRef::getAlignment() const {
 462   return OwningObject->getSectionAlignment(SectionPimpl);
 463 }
 464
 465 inline bool SectionRef::isCompressed() const {
 466   return OwningObject->isSectionCompressed(SectionPimpl);
 467 }
 468
 469 inline bool SectionRef::isText() const {
 470   return OwningObject->isSectionText(SectionPimpl);
 471 }
 472
 473 inline bool SectionRef::isData() const {
 474   return OwningObject->isSectionData(SectionPimpl);
 475 }
 476
 477 inline bool SectionRef::isBSS() const {
 478   return OwningObject->isSectionBSS(SectionPimpl);
 479 }
 480
 481 inline bool SectionRef::isVirtual() const {
 482   return OwningObject->isSectionVirtual(SectionPimpl);
 483 }
 484
 485 inline bool SectionRef::isBitcode() const {
 486   return OwningObject->isSectionBitcode(SectionPimpl);
 487 }
 488
 489 inline bool SectionRef::isStripped() const {
 490   return OwningObject->isSectionStripped(SectionPimpl);
 491 }
 492
 493 inline bool SectionRef::isBerkeleyText() const {
 494   return OwningObject->isBerkeleyText(SectionPimpl);
 495 }
 496
 497 inline bool SectionRef::isBerkeleyData() const {
 498   return OwningObject->isBerkeleyData(SectionPimpl);
 499 }
 500
 501 inline relocation_iterator SectionRef::relocation_begin() const {
 502   return OwningObject->section_rel_begin(SectionPimpl);
 503 }
 504
 505 inline relocation_iterator SectionRef::relocation_end() const {
 506   return OwningObject->section_rel_end(SectionPimpl);
 507 }
 508
 509 inline section_iterator SectionRef::getRelocatedSection() const {
 510   return OwningObject->getRelocatedSection(SectionPimpl);
 511 }
 512
 513 inline DataRefImpl SectionRef::getRawDataRefImpl() const {
 514   return SectionPimpl;
 515 }
 516
 517 inline const ObjectFile *SectionRef::getObject() const {
 518   return OwningObject;
 519 }
 520
 521 /// RelocationRef
 522 inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
 523                               const ObjectFile *Owner)
 524   : RelocationPimpl(RelocationP)
 525   , OwningObject(Owner) {}
 526
 527 inline bool RelocationRef::operator==(const RelocationRef &Other) const {
 528   return RelocationPimpl == Other.RelocationPimpl;
 529 }
 530
 531 inline void RelocationRef::moveNext() {
 532   return OwningObject->moveRelocationNext(RelocationPimpl);
 533 }
 534
 535 inline uint64_t RelocationRef::getOffset() const {
 536   return OwningObject->getRelocationOffset(RelocationPimpl);
 537 }
 538
 539 inline symbol_iterator RelocationRef::getSymbol() const {
 540   return OwningObject->getRelocationSymbol(RelocationPimpl);
 541 }
 542
 543 inline uint64_t RelocationRef::getType() const {
 544   return OwningObject->getRelocationType(RelocationPimpl);
 545 }
 546
 547 inline void RelocationRef::getTypeName(SmallVectorImpl<char> &Result) const {
 548   return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
 549 }
 550
 551 inline DataRefImpl RelocationRef::getRawDataRefImpl() const {
 552   return RelocationPimpl;
 553 }
 554
 555 inline const ObjectFile *RelocationRef::getObject() const {
 556   return OwningObject;
 557 }
 558
 559 } // end namespace object
 560
 561 template <> struct DenseMapInfo<object::SectionRef> {
 562   static bool isEqual(const object::SectionRef &A,
 563                       const object::SectionRef &B) {
 564     return A == B;
 565   }
 566   static object::SectionRef getEmptyKey() {
 567     return object::SectionRef({}, nullptr);
 568   }
 569   static object::SectionRef getTombstoneKey() {
 570     object::DataRefImpl TS;
 571     TS.p = (uintptr_t)-1;
 572     return object::SectionRef(TS, nullptr);
 573   }
 574   static unsigned getHashValue(const object::SectionRef &Sec) {
 575     object::DataRefImpl Raw = Sec.getRawDataRefImpl();
 576     return hash_combine(Raw.p, Raw.d.a, Raw.d.b);
 577   }
 578 };
 579
 580 } // end namespace llvm
 581
 582 #endif // LLVM_OBJECT_OBJECTFILE_H