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:
DWARFUnitSection()65   DWARFUnitSection() : Parsed(false) {}
DWARFUnitSection(DWARFUnitSection && DUS)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 
getUnitForOffset(uint32_t Offset)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:
parseImpl(DWARFContext & Context,const DWARFSection & Section,const DWARFDebugAbbrev * DA,StringRef RS,StringRef SS,StringRef SOS,StringRef AOS,StringRef LS,bool LE)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);
getUnit()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.
getHeaderSize()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 
getContext()157   DWARFContext& getContext() const { return Context; }
158 
getLineSection()159   StringRef getLineSection() const { return LineSection; }
getStringSection()160   StringRef getStringSection() const { return StringSection; }
getStringOffsetSection()161   StringRef getStringOffsetSection() const { return StringOffsetSection; }
setAddrOffsetSection(StringRef AOS,uint32_t Base)162   void setAddrOffsetSection(StringRef AOS, uint32_t Base) {
163     AddrOffsetSection = AOS;
164     AddrOffsetSectionBase = Base;
165   }
setRangesSection(StringRef RS,uint32_t Base)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 
getDebugInfoExtractor()175   DataExtractor getDebugInfoExtractor() const {
176     return DataExtractor(InfoSection.Data, isLittleEndian, AddrSize);
177   }
getStringExtractor()178   DataExtractor getStringExtractor() const {
179     return DataExtractor(StringSection, false, 0);
180   }
181 
getRelocMap()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();
getOffset()192   uint32_t getOffset() const { return Offset; }
getNextUnitOffset()193   uint32_t getNextUnitOffset() const { return Offset + Length + 4; }
getLength()194   uint32_t getLength() const { return Length; }
getVersion()195   uint16_t getVersion() const { return Version; }
getAbbreviations()196   const DWARFAbbreviationDeclarationSet *getAbbreviations() const {
197     return Abbrevs;
198   }
getAddressByteSize()199   uint8_t getAddressByteSize() const { return AddrSize; }
getBaseAddress()200   uint64_t getBaseAddress() const { return BaseAddr; }
201 
setBaseAddress(uint64_t base_addr)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.
getUnitSection()222   const DWARFUnitSectionBase &getUnitSection() const { return UnitSection; }
223 
224   /// \brief Returns the number of DIEs in the unit. Parses the unit
225   /// if necessary.
getNumDIEs()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().
getDIEIndex(const DWARFDebugInfoEntryMinimal * DIE)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.
getDIEAtIndex(unsigned 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.
getDIEForOffset(uint32_t Offset)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 
getLineTableOffset()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.
getDebugInfoSize()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