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      1 //===-- DWARFUnit.h ---------------------------------------------*- 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 #ifndef LLVM_LIB_DEBUGINFO_DWARFUNIT_H
     11 #define LLVM_LIB_DEBUGINFO_DWARFUNIT_H
     12 
     13 #include "llvm/ADT/STLExtras.h"
     14 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
     15 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
     16 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
     17 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
     18 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
     19 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
     20 #include <vector>
     21 
     22 namespace llvm {
     23 
     24 namespace object {
     25 class ObjectFile;
     26 }
     27 
     28 class DWARFContext;
     29 class DWARFDebugAbbrev;
     30 class DWARFUnit;
     31 class StringRef;
     32 class raw_ostream;
     33 
     34 /// Base class for all DWARFUnitSection classes. This provides the
     35 /// functionality common to all unit types.
     36 class DWARFUnitSectionBase {
     37 public:
     38   /// Returns the Unit that contains the given section offset in the
     39   /// same section this Unit originated from.
     40   virtual DWARFUnit *getUnitForOffset(uint32_t Offset) const = 0;
     41 
     42   void parse(DWARFContext &C, const DWARFSection &Section);
     43   void parseDWO(DWARFContext &C, const DWARFSection &DWOSection,
     44                 DWARFUnitIndex *Index = nullptr);
     45 
     46 protected:
     47   virtual void parseImpl(DWARFContext &Context, const DWARFSection &Section,
     48                          const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
     49                          StringRef SOS, StringRef AOS, StringRef LS,
     50                          bool isLittleEndian) = 0;
     51 
     52   ~DWARFUnitSectionBase() = default;
     53 };
     54 
     55 const DWARFUnitIndex &getDWARFUnitIndex(DWARFContext &Context,
     56                                         DWARFSectionKind Kind);
     57 
     58 /// Concrete instance of DWARFUnitSection, specialized for one Unit type.
     59 template<typename UnitType>
     60 class DWARFUnitSection final : public SmallVector<std::unique_ptr<UnitType>, 1>,
     61                                public DWARFUnitSectionBase {
     62   bool Parsed;
     63 
     64 public:
     65   DWARFUnitSection() : Parsed(false) {}
     66   DWARFUnitSection(DWARFUnitSection &&DUS) :
     67     SmallVector<std::unique_ptr<UnitType>, 1>(std::move(DUS)), Parsed(DUS.Parsed) {}
     68 
     69   typedef llvm::SmallVectorImpl<std::unique_ptr<UnitType>> UnitVector;
     70   typedef typename UnitVector::iterator iterator;
     71   typedef llvm::iterator_range<typename UnitVector::iterator> iterator_range;
     72 
     73   UnitType *getUnitForOffset(uint32_t Offset) const override {
     74     auto *CU = std::upper_bound(
     75         this->begin(), this->end(), Offset,
     76         [](uint32_t LHS, const std::unique_ptr<UnitType> &RHS) {
     77           return LHS < RHS->getNextUnitOffset();
     78         });
     79     if (CU != this->end())
     80       return CU->get();
     81     return nullptr;
     82   }
     83 
     84 private:
     85   void parseImpl(DWARFContext &Context, const DWARFSection &Section,
     86                  const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
     87                  StringRef SOS, StringRef AOS, StringRef LS, bool LE) override {
     88     if (Parsed)
     89       return;
     90     const auto &Index = getDWARFUnitIndex(Context, UnitType::Section);
     91     DataExtractor Data(Section.Data, LE, 0);
     92     uint32_t Offset = 0;
     93     while (Data.isValidOffset(Offset)) {
     94       auto U = llvm::make_unique<UnitType>(Context, Section, DA, RS, SS, SOS,
     95                                            AOS, LS, LE, *this,
     96                                            Index.getFromOffset(Offset));
     97       if (!U->extract(Data, &Offset))
     98         break;
     99       this->push_back(std::move(U));
    100       Offset = this->back()->getNextUnitOffset();
    101     }
    102     Parsed = true;
    103   }
    104 };
    105 
    106 class DWARFUnit {
    107   DWARFContext &Context;
    108   // Section containing this DWARFUnit.
    109   const DWARFSection &InfoSection;
    110 
    111   const DWARFDebugAbbrev *Abbrev;
    112   StringRef RangeSection;
    113   uint32_t RangeSectionBase;
    114   StringRef LineSection;
    115   StringRef StringSection;
    116   StringRef StringOffsetSection;
    117   StringRef AddrOffsetSection;
    118   uint32_t AddrOffsetSectionBase;
    119   bool isLittleEndian;
    120   const DWARFUnitSectionBase &UnitSection;
    121 
    122   uint32_t Offset;
    123   uint32_t Length;
    124   uint16_t Version;
    125   const DWARFAbbreviationDeclarationSet *Abbrevs;
    126   uint8_t AddrSize;
    127   uint64_t BaseAddr;
    128   // The compile unit debug information entry items.
    129   std::vector<DWARFDebugInfoEntryMinimal> DieArray;
    130 
    131   class DWOHolder {
    132     object::OwningBinary<object::ObjectFile> DWOFile;
    133     std::unique_ptr<DWARFContext> DWOContext;
    134     DWARFUnit *DWOU;
    135   public:
    136     DWOHolder(StringRef DWOPath);
    137     DWARFUnit *getUnit() const { return DWOU; }
    138   };
    139   std::unique_ptr<DWOHolder> DWO;
    140 
    141   const DWARFUnitIndex::Entry *IndexEntry;
    142 
    143 protected:
    144   virtual bool extractImpl(DataExtractor debug_info, uint32_t *offset_ptr);
    145   /// Size in bytes of the unit header.
    146   virtual uint32_t getHeaderSize() const { return 11; }
    147 
    148 public:
    149   DWARFUnit(DWARFContext &Context, const DWARFSection &Section,
    150             const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
    151             StringRef SOS, StringRef AOS, StringRef LS, bool LE,
    152             const DWARFUnitSectionBase &UnitSection,
    153             const DWARFUnitIndex::Entry *IndexEntry = nullptr);
    154 
    155   virtual ~DWARFUnit();
    156 
    157   DWARFContext& getContext() const { return Context; }
    158 
    159   StringRef getLineSection() const { return LineSection; }
    160   StringRef getStringSection() const { return StringSection; }
    161   StringRef getStringOffsetSection() const { return StringOffsetSection; }
    162   void setAddrOffsetSection(StringRef AOS, uint32_t Base) {
    163     AddrOffsetSection = AOS;
    164     AddrOffsetSectionBase = Base;
    165   }
    166   void setRangesSection(StringRef RS, uint32_t Base) {
    167     RangeSection = RS;
    168     RangeSectionBase = Base;
    169   }
    170 
    171   bool getAddrOffsetSectionItem(uint32_t Index, uint64_t &Result) const;
    172   // FIXME: Result should be uint64_t in DWARF64.
    173   bool getStringOffsetSectionItem(uint32_t Index, uint32_t &Result) const;
    174 
    175   DataExtractor getDebugInfoExtractor() const {
    176     return DataExtractor(InfoSection.Data, isLittleEndian, AddrSize);
    177   }
    178   DataExtractor getStringExtractor() const {
    179     return DataExtractor(StringSection, false, 0);
    180   }
    181 
    182   const RelocAddrMap *getRelocMap() const { return &InfoSection.Relocs; }
    183 
    184   bool extract(DataExtractor debug_info, uint32_t* offset_ptr);
    185 
    186   /// extractRangeList - extracts the range list referenced by this compile
    187   /// unit from .debug_ranges section. Returns true on success.
    188   /// Requires that compile unit is already extracted.
    189   bool extractRangeList(uint32_t RangeListOffset,
    190                         DWARFDebugRangeList &RangeList) const;
    191   void clear();
    192   uint32_t getOffset() const { return Offset; }
    193   uint32_t getNextUnitOffset() const { return Offset + Length + 4; }
    194   uint32_t getLength() const { return Length; }
    195   uint16_t getVersion() const { return Version; }
    196   const DWARFAbbreviationDeclarationSet *getAbbreviations() const {
    197     return Abbrevs;
    198   }
    199   uint8_t getAddressByteSize() const { return AddrSize; }
    200   uint64_t getBaseAddress() const { return BaseAddr; }
    201 
    202   void setBaseAddress(uint64_t base_addr) {
    203     BaseAddr = base_addr;
    204   }
    205 
    206   const DWARFDebugInfoEntryMinimal *getUnitDIE(bool ExtractUnitDIEOnly = true) {
    207     extractDIEsIfNeeded(ExtractUnitDIEOnly);
    208     return DieArray.empty() ? nullptr : &DieArray[0];
    209   }
    210 
    211   const char *getCompilationDir();
    212   uint64_t getDWOId();
    213 
    214   void collectAddressRanges(DWARFAddressRangesVector &CURanges);
    215 
    216   /// getInlinedChainForAddress - fetches inlined chain for a given address.
    217   /// Returns empty chain if there is no subprogram containing address. The
    218   /// chain is valid as long as parsed compile unit DIEs are not cleared.
    219   DWARFDebugInfoEntryInlinedChain getInlinedChainForAddress(uint64_t Address);
    220 
    221   /// getUnitSection - Return the DWARFUnitSection containing this unit.
    222   const DWARFUnitSectionBase &getUnitSection() const { return UnitSection; }
    223 
    224   /// \brief Returns the number of DIEs in the unit. Parses the unit
    225   /// if necessary.
    226   unsigned getNumDIEs() {
    227     extractDIEsIfNeeded(false);
    228     return DieArray.size();
    229   }
    230 
    231   /// \brief Return the index of a DIE inside the unit's DIE vector.
    232   ///
    233   /// It is illegal to call this method with a DIE that hasn't be
    234   /// created by this unit. In other word, it's illegal to call this
    235   /// method on a DIE that isn't accessible by following
    236   /// children/sibling links starting from this unit's getUnitDIE().
    237   uint32_t getDIEIndex(const DWARFDebugInfoEntryMinimal *DIE) {
    238     assert(!DieArray.empty() && DIE >= &DieArray[0] &&
    239            DIE < &DieArray[0] + DieArray.size());
    240     return DIE - &DieArray[0];
    241   }
    242 
    243   /// \brief Return the DIE object at the given index.
    244   const DWARFDebugInfoEntryMinimal *getDIEAtIndex(unsigned Index) const {
    245     assert(Index < DieArray.size());
    246     return &DieArray[Index];
    247   }
    248 
    249   /// \brief Return the DIE object for a given offset inside the
    250   /// unit's DIE vector.
    251   ///
    252   /// The unit needs to have his DIEs extracted for this method to work.
    253   const DWARFDebugInfoEntryMinimal *getDIEForOffset(uint32_t Offset) const {
    254     assert(!DieArray.empty());
    255     auto it = std::lower_bound(
    256         DieArray.begin(), DieArray.end(), Offset,
    257         [](const DWARFDebugInfoEntryMinimal &LHS, uint32_t Offset) {
    258           return LHS.getOffset() < Offset;
    259         });
    260     return it == DieArray.end() ? nullptr : &*it;
    261   }
    262 
    263   uint32_t getLineTableOffset() const {
    264     if (IndexEntry)
    265       if (const auto *Contrib = IndexEntry->getOffset(DW_SECT_LINE))
    266         return Contrib->Offset;
    267     return 0;
    268   }
    269 
    270 private:
    271   /// Size in bytes of the .debug_info data associated with this compile unit.
    272   size_t getDebugInfoSize() const { return Length + 4 - getHeaderSize(); }
    273 
    274   /// extractDIEsIfNeeded - Parses a compile unit and indexes its DIEs if it
    275   /// hasn't already been done. Returns the number of DIEs parsed at this call.
    276   size_t extractDIEsIfNeeded(bool CUDieOnly);
    277   /// extractDIEsToVector - Appends all parsed DIEs to a vector.
    278   void extractDIEsToVector(bool AppendCUDie, bool AppendNonCUDIEs,
    279                            std::vector<DWARFDebugInfoEntryMinimal> &DIEs) const;
    280   /// setDIERelations - We read in all of the DIE entries into our flat list
    281   /// of DIE entries and now we need to go back through all of them and set the
    282   /// parent, sibling and child pointers for quick DIE navigation.
    283   void setDIERelations();
    284   /// clearDIEs - Clear parsed DIEs to keep memory usage low.
    285   void clearDIEs(bool KeepCUDie);
    286 
    287   /// parseDWO - Parses .dwo file for current compile unit. Returns true if
    288   /// it was actually constructed.
    289   bool parseDWO();
    290 
    291   /// getSubprogramForAddress - Returns subprogram DIE with address range
    292   /// encompassing the provided address. The pointer is alive as long as parsed
    293   /// compile unit DIEs are not cleared.
    294   const DWARFDebugInfoEntryMinimal *getSubprogramForAddress(uint64_t Address);
    295 };
    296 
    297 }
    298 
    299 #endif
    300