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      1 //===- ObjectFile.h - File format independent object file -------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file declares a file format independent ObjectFile class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_OBJECT_OBJECTFILE_H
     15 #define LLVM_OBJECT_OBJECTFILE_H
     16 
     17 #include "llvm/ADT/StringRef.h"
     18 #include "llvm/Object/SymbolicFile.h"
     19 #include "llvm/Support/DataTypes.h"
     20 #include "llvm/Support/ErrorHandling.h"
     21 #include "llvm/Support/FileSystem.h"
     22 #include "llvm/Support/MemoryBuffer.h"
     23 #include <cstring>
     24 #include <vector>
     25 
     26 namespace llvm {
     27 namespace object {
     28 
     29 class ObjectFile;
     30 class COFFObjectFile;
     31 class MachOObjectFile;
     32 
     33 class SymbolRef;
     34 class symbol_iterator;
     35 
     36 /// RelocationRef - This is a value type class that represents a single
     37 /// relocation in the list of relocations in the object file.
     38 class RelocationRef {
     39   DataRefImpl RelocationPimpl;
     40   const ObjectFile *OwningObject;
     41 
     42 public:
     43   RelocationRef() : OwningObject(nullptr) { }
     44 
     45   RelocationRef(DataRefImpl RelocationP, const ObjectFile *Owner);
     46 
     47   bool operator==(const RelocationRef &Other) const;
     48 
     49   void moveNext();
     50 
     51   std::error_code getAddress(uint64_t &Result) const;
     52   std::error_code getOffset(uint64_t &Result) const;
     53   symbol_iterator getSymbol() const;
     54   std::error_code getType(uint64_t &Result) const;
     55 
     56   /// @brief Indicates whether this relocation should hidden when listing
     57   /// relocations, usually because it is the trailing part of a multipart
     58   /// relocation that will be printed as part of the leading relocation.
     59   std::error_code getHidden(bool &Result) const;
     60 
     61   /// @brief Get a string that represents the type of this relocation.
     62   ///
     63   /// This is for display purposes only.
     64   std::error_code getTypeName(SmallVectorImpl<char> &Result) const;
     65 
     66   /// @brief Get a string that represents the calculation of the value of this
     67   ///        relocation.
     68   ///
     69   /// This is for display purposes only.
     70   std::error_code getValueString(SmallVectorImpl<char> &Result) const;
     71 
     72   DataRefImpl getRawDataRefImpl() const;
     73   const ObjectFile *getObjectFile() const;
     74 };
     75 typedef content_iterator<RelocationRef> relocation_iterator;
     76 
     77 /// SectionRef - This is a value type class that represents a single section in
     78 /// the list of sections in the object file.
     79 class SectionRef;
     80 typedef content_iterator<SectionRef> section_iterator;
     81 class SectionRef {
     82   friend class SymbolRef;
     83   DataRefImpl SectionPimpl;
     84   const ObjectFile *OwningObject;
     85 
     86 public:
     87   SectionRef() : OwningObject(nullptr) { }
     88 
     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   std::error_code getName(StringRef &Result) const;
     98   uint64_t getAddress() const;
     99   uint64_t getSize() const;
    100   std::error_code getContents(StringRef &Result) const;
    101 
    102   /// @brief Get the alignment of this section as the actual value (not log 2).
    103   uint64_t getAlignment() const;
    104 
    105   bool isText() const;
    106   bool isData() const;
    107   bool isBSS() const;
    108   bool isVirtual() const;
    109 
    110   bool containsSymbol(SymbolRef S) const;
    111 
    112   relocation_iterator relocation_begin() const;
    113   relocation_iterator relocation_end() const;
    114   iterator_range<relocation_iterator> relocations() const {
    115     return iterator_range<relocation_iterator>(relocation_begin(),
    116                                                relocation_end());
    117   }
    118   section_iterator getRelocatedSection() const;
    119 
    120   DataRefImpl getRawDataRefImpl() const;
    121   const ObjectFile *getObject() const;
    122 };
    123 
    124 /// SymbolRef - This is a value type class that represents a single symbol in
    125 /// the list of symbols in the object file.
    126 class SymbolRef : public BasicSymbolRef {
    127   friend class SectionRef;
    128 
    129 public:
    130   SymbolRef() : BasicSymbolRef() {}
    131 
    132   enum Type {
    133     ST_Unknown, // Type not specified
    134     ST_Data,
    135     ST_Debug,
    136     ST_File,
    137     ST_Function,
    138     ST_Other
    139   };
    140 
    141   SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner);
    142 
    143   std::error_code getName(StringRef &Result) const;
    144   /// Returns the symbol virtual address (i.e. address at which it will be
    145   /// mapped).
    146   std::error_code getAddress(uint64_t &Result) const;
    147   /// @brief Get the alignment of this symbol as the actual value (not log 2).
    148   std::error_code getAlignment(uint32_t &Result) const;
    149   std::error_code getSize(uint64_t &Result) const;
    150   std::error_code getType(SymbolRef::Type &Result) const;
    151   std::error_code getOther(uint8_t &Result) const;
    152 
    153   /// @brief Get section this symbol is defined in reference to. Result is
    154   /// end_sections() if it is undefined or is an absolute symbol.
    155   std::error_code getSection(section_iterator &Result) const;
    156 
    157   const ObjectFile *getObject() const;
    158 };
    159 
    160 class symbol_iterator : public basic_symbol_iterator {
    161 public:
    162   symbol_iterator(SymbolRef Sym) : basic_symbol_iterator(Sym) {}
    163   symbol_iterator(const basic_symbol_iterator &B)
    164       : basic_symbol_iterator(SymbolRef(B->getRawDataRefImpl(),
    165                                         cast<ObjectFile>(B->getObject()))) {}
    166 
    167   const SymbolRef *operator->() const {
    168     const BasicSymbolRef &P = basic_symbol_iterator::operator *();
    169     return static_cast<const SymbolRef*>(&P);
    170   }
    171 
    172   const SymbolRef &operator*() const {
    173     const BasicSymbolRef &P = basic_symbol_iterator::operator *();
    174     return static_cast<const SymbolRef&>(P);
    175   }
    176 };
    177 
    178 /// ObjectFile - This class is the base class for all object file types.
    179 /// Concrete instances of this object are created by createObjectFile, which
    180 /// figures out which type to create.
    181 class ObjectFile : public SymbolicFile {
    182   virtual void anchor();
    183   ObjectFile() = delete;
    184   ObjectFile(const ObjectFile &other) = delete;
    185 
    186 protected:
    187   ObjectFile(unsigned int Type, MemoryBufferRef Source);
    188 
    189   const uint8_t *base() const {
    190     return reinterpret_cast<const uint8_t *>(Data.getBufferStart());
    191   }
    192 
    193   // These functions are for SymbolRef to call internally. The main goal of
    194   // this is to allow SymbolRef::SymbolPimpl to point directly to the symbol
    195   // entry in the memory mapped object file. SymbolPimpl cannot contain any
    196   // virtual functions because then it could not point into the memory mapped
    197   // file.
    198   //
    199   // Implementations assume that the DataRefImpl is valid and has not been
    200   // modified externally. It's UB otherwise.
    201   friend class SymbolRef;
    202   virtual std::error_code getSymbolName(DataRefImpl Symb,
    203                                         StringRef &Res) const = 0;
    204   std::error_code printSymbolName(raw_ostream &OS,
    205                                   DataRefImpl Symb) const override;
    206   virtual std::error_code getSymbolAddress(DataRefImpl Symb,
    207                                            uint64_t &Res) const = 0;
    208   virtual std::error_code getSymbolAlignment(DataRefImpl Symb,
    209                                              uint32_t &Res) const;
    210   virtual std::error_code getSymbolSize(DataRefImpl Symb,
    211                                         uint64_t &Res) const = 0;
    212   virtual std::error_code getSymbolType(DataRefImpl Symb,
    213                                         SymbolRef::Type &Res) const = 0;
    214   virtual std::error_code getSymbolSection(DataRefImpl Symb,
    215                                            section_iterator &Res) const = 0;
    216   virtual std::error_code getSymbolOther(DataRefImpl Symb,
    217                                          uint8_t &Res) const {
    218     return object_error::invalid_file_type;
    219   }
    220 
    221   // Same as above for SectionRef.
    222   friend class SectionRef;
    223   virtual void moveSectionNext(DataRefImpl &Sec) const = 0;
    224   virtual std::error_code getSectionName(DataRefImpl Sec,
    225                                          StringRef &Res) const = 0;
    226   virtual uint64_t getSectionAddress(DataRefImpl Sec) const = 0;
    227   virtual uint64_t getSectionSize(DataRefImpl Sec) const = 0;
    228   virtual std::error_code getSectionContents(DataRefImpl Sec,
    229                                              StringRef &Res) const = 0;
    230   virtual uint64_t getSectionAlignment(DataRefImpl Sec) const = 0;
    231   virtual bool isSectionText(DataRefImpl Sec) const = 0;
    232   virtual bool isSectionData(DataRefImpl Sec) const = 0;
    233   virtual bool isSectionBSS(DataRefImpl Sec) const = 0;
    234   // A section is 'virtual' if its contents aren't present in the object image.
    235   virtual bool isSectionVirtual(DataRefImpl Sec) const = 0;
    236   virtual bool sectionContainsSymbol(DataRefImpl Sec,
    237                                      DataRefImpl Symb) const = 0;
    238   virtual relocation_iterator section_rel_begin(DataRefImpl Sec) const = 0;
    239   virtual relocation_iterator section_rel_end(DataRefImpl Sec) const = 0;
    240   virtual section_iterator getRelocatedSection(DataRefImpl Sec) const;
    241 
    242   // Same as above for RelocationRef.
    243   friend class RelocationRef;
    244   virtual void moveRelocationNext(DataRefImpl &Rel) const = 0;
    245   virtual std::error_code getRelocationAddress(DataRefImpl Rel,
    246                                                uint64_t &Res) const = 0;
    247   virtual std::error_code getRelocationOffset(DataRefImpl Rel,
    248                                               uint64_t &Res) const = 0;
    249   virtual symbol_iterator getRelocationSymbol(DataRefImpl Rel) const = 0;
    250   virtual std::error_code getRelocationType(DataRefImpl Rel,
    251                                             uint64_t &Res) const = 0;
    252   virtual std::error_code
    253   getRelocationTypeName(DataRefImpl Rel,
    254                         SmallVectorImpl<char> &Result) const = 0;
    255   virtual std::error_code
    256   getRelocationValueString(DataRefImpl Rel,
    257                            SmallVectorImpl<char> &Result) const = 0;
    258   virtual std::error_code getRelocationHidden(DataRefImpl Rel,
    259                                               bool &Result) const {
    260     Result = false;
    261     return object_error::success;
    262   }
    263 
    264 public:
    265   typedef iterator_range<symbol_iterator> symbol_iterator_range;
    266   symbol_iterator_range symbols() const {
    267     return symbol_iterator_range(symbol_begin(), symbol_end());
    268   }
    269 
    270   virtual section_iterator section_begin() const = 0;
    271   virtual section_iterator section_end() const = 0;
    272 
    273   typedef iterator_range<section_iterator> section_iterator_range;
    274   section_iterator_range sections() const {
    275     return section_iterator_range(section_begin(), section_end());
    276   }
    277 
    278   /// @brief The number of bytes used to represent an address in this object
    279   ///        file format.
    280   virtual uint8_t getBytesInAddress() const = 0;
    281 
    282   virtual StringRef getFileFormatName() const = 0;
    283   virtual /* Triple::ArchType */ unsigned getArch() const = 0;
    284 
    285   /// Returns platform-specific object flags, if any.
    286   virtual std::error_code getPlatformFlags(unsigned &Result) const {
    287     Result = 0;
    288     return object_error::invalid_file_type;
    289   }
    290 
    291   /// True if this is a relocatable object (.o/.obj).
    292   virtual bool isRelocatableObject() const = 0;
    293 
    294   /// @returns Pointer to ObjectFile subclass to handle this type of object.
    295   /// @param ObjectPath The path to the object file. ObjectPath.isObject must
    296   ///        return true.
    297   /// @brief Create ObjectFile from path.
    298   static ErrorOr<OwningBinary<ObjectFile>>
    299   createObjectFile(StringRef ObjectPath);
    300 
    301   static ErrorOr<std::unique_ptr<ObjectFile>>
    302   createObjectFile(MemoryBufferRef Object, sys::fs::file_magic Type);
    303   static ErrorOr<std::unique_ptr<ObjectFile>>
    304   createObjectFile(MemoryBufferRef Object) {
    305     return createObjectFile(Object, sys::fs::file_magic::unknown);
    306   }
    307 
    308 
    309   static inline bool classof(const Binary *v) {
    310     return v->isObject();
    311   }
    312 
    313   static ErrorOr<std::unique_ptr<COFFObjectFile>>
    314   createCOFFObjectFile(MemoryBufferRef Object);
    315 
    316   static ErrorOr<std::unique_ptr<ObjectFile>>
    317   createELFObjectFile(MemoryBufferRef Object);
    318 
    319   static ErrorOr<std::unique_ptr<MachOObjectFile>>
    320   createMachOObjectFile(MemoryBufferRef Object);
    321 };
    322 
    323 // Inline function definitions.
    324 inline SymbolRef::SymbolRef(DataRefImpl SymbolP, const ObjectFile *Owner)
    325     : BasicSymbolRef(SymbolP, Owner) {}
    326 
    327 inline std::error_code SymbolRef::getName(StringRef &Result) const {
    328   return getObject()->getSymbolName(getRawDataRefImpl(), Result);
    329 }
    330 
    331 inline std::error_code SymbolRef::getAddress(uint64_t &Result) const {
    332   return getObject()->getSymbolAddress(getRawDataRefImpl(), Result);
    333 }
    334 
    335 inline std::error_code SymbolRef::getAlignment(uint32_t &Result) const {
    336   return getObject()->getSymbolAlignment(getRawDataRefImpl(), Result);
    337 }
    338 
    339 inline std::error_code SymbolRef::getSize(uint64_t &Result) const {
    340   return getObject()->getSymbolSize(getRawDataRefImpl(), Result);
    341 }
    342 
    343 inline std::error_code SymbolRef::getSection(section_iterator &Result) const {
    344   return getObject()->getSymbolSection(getRawDataRefImpl(), Result);
    345 }
    346 
    347 inline std::error_code SymbolRef::getType(SymbolRef::Type &Result) const {
    348   return getObject()->getSymbolType(getRawDataRefImpl(), Result);
    349 }
    350 
    351 inline std::error_code SymbolRef::getOther(uint8_t &Result) const {
    352   return getObject()->getSymbolOther(getRawDataRefImpl(), Result);
    353 }
    354 
    355 inline const ObjectFile *SymbolRef::getObject() const {
    356   const SymbolicFile *O = BasicSymbolRef::getObject();
    357   return cast<ObjectFile>(O);
    358 }
    359 
    360 
    361 /// SectionRef
    362 inline SectionRef::SectionRef(DataRefImpl SectionP,
    363                               const ObjectFile *Owner)
    364   : SectionPimpl(SectionP)
    365   , OwningObject(Owner) {}
    366 
    367 inline bool SectionRef::operator==(const SectionRef &Other) const {
    368   return SectionPimpl == Other.SectionPimpl;
    369 }
    370 
    371 inline bool SectionRef::operator!=(const SectionRef &Other) const {
    372   return SectionPimpl != Other.SectionPimpl;
    373 }
    374 
    375 inline bool SectionRef::operator<(const SectionRef &Other) const {
    376   return SectionPimpl < Other.SectionPimpl;
    377 }
    378 
    379 inline void SectionRef::moveNext() {
    380   return OwningObject->moveSectionNext(SectionPimpl);
    381 }
    382 
    383 inline std::error_code SectionRef::getName(StringRef &Result) const {
    384   return OwningObject->getSectionName(SectionPimpl, Result);
    385 }
    386 
    387 inline uint64_t SectionRef::getAddress() const {
    388   return OwningObject->getSectionAddress(SectionPimpl);
    389 }
    390 
    391 inline uint64_t SectionRef::getSize() const {
    392   return OwningObject->getSectionSize(SectionPimpl);
    393 }
    394 
    395 inline std::error_code SectionRef::getContents(StringRef &Result) const {
    396   return OwningObject->getSectionContents(SectionPimpl, Result);
    397 }
    398 
    399 inline uint64_t SectionRef::getAlignment() const {
    400   return OwningObject->getSectionAlignment(SectionPimpl);
    401 }
    402 
    403 inline bool SectionRef::isText() const {
    404   return OwningObject->isSectionText(SectionPimpl);
    405 }
    406 
    407 inline bool SectionRef::isData() const {
    408   return OwningObject->isSectionData(SectionPimpl);
    409 }
    410 
    411 inline bool SectionRef::isBSS() const {
    412   return OwningObject->isSectionBSS(SectionPimpl);
    413 }
    414 
    415 inline bool SectionRef::isVirtual() const {
    416   return OwningObject->isSectionVirtual(SectionPimpl);
    417 }
    418 
    419 inline bool SectionRef::containsSymbol(SymbolRef S) const {
    420   return OwningObject->sectionContainsSymbol(SectionPimpl,
    421                                              S.getRawDataRefImpl());
    422 }
    423 
    424 inline relocation_iterator SectionRef::relocation_begin() const {
    425   return OwningObject->section_rel_begin(SectionPimpl);
    426 }
    427 
    428 inline relocation_iterator SectionRef::relocation_end() const {
    429   return OwningObject->section_rel_end(SectionPimpl);
    430 }
    431 
    432 inline section_iterator SectionRef::getRelocatedSection() const {
    433   return OwningObject->getRelocatedSection(SectionPimpl);
    434 }
    435 
    436 inline DataRefImpl SectionRef::getRawDataRefImpl() const {
    437   return SectionPimpl;
    438 }
    439 
    440 inline const ObjectFile *SectionRef::getObject() const {
    441   return OwningObject;
    442 }
    443 
    444 /// RelocationRef
    445 inline RelocationRef::RelocationRef(DataRefImpl RelocationP,
    446                               const ObjectFile *Owner)
    447   : RelocationPimpl(RelocationP)
    448   , OwningObject(Owner) {}
    449 
    450 inline bool RelocationRef::operator==(const RelocationRef &Other) const {
    451   return RelocationPimpl == Other.RelocationPimpl;
    452 }
    453 
    454 inline void RelocationRef::moveNext() {
    455   return OwningObject->moveRelocationNext(RelocationPimpl);
    456 }
    457 
    458 inline std::error_code RelocationRef::getAddress(uint64_t &Result) const {
    459   return OwningObject->getRelocationAddress(RelocationPimpl, Result);
    460 }
    461 
    462 inline std::error_code RelocationRef::getOffset(uint64_t &Result) const {
    463   return OwningObject->getRelocationOffset(RelocationPimpl, Result);
    464 }
    465 
    466 inline symbol_iterator RelocationRef::getSymbol() const {
    467   return OwningObject->getRelocationSymbol(RelocationPimpl);
    468 }
    469 
    470 inline std::error_code RelocationRef::getType(uint64_t &Result) const {
    471   return OwningObject->getRelocationType(RelocationPimpl, Result);
    472 }
    473 
    474 inline std::error_code
    475 RelocationRef::getTypeName(SmallVectorImpl<char> &Result) const {
    476   return OwningObject->getRelocationTypeName(RelocationPimpl, Result);
    477 }
    478 
    479 inline std::error_code
    480 RelocationRef::getValueString(SmallVectorImpl<char> &Result) const {
    481   return OwningObject->getRelocationValueString(RelocationPimpl, Result);
    482 }
    483 
    484 inline std::error_code RelocationRef::getHidden(bool &Result) const {
    485   return OwningObject->getRelocationHidden(RelocationPimpl, Result);
    486 }
    487 
    488 inline DataRefImpl RelocationRef::getRawDataRefImpl() const {
    489   return RelocationPimpl;
    490 }
    491 
    492 inline const ObjectFile *RelocationRef::getObjectFile() const {
    493   return OwningObject;
    494 }
    495 
    496 
    497 } // end namespace object
    498 } // end namespace llvm
    499 
    500 #endif
    501