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