include/llvm/DebugInfo/DWARF/DWARFUnit.h

   1 //===- DWARFUnit.h ----------------------------------------------*- 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 #ifndef LLVM_DEBUGINFO_DWARF_DWARFUNIT_H
  10 #define LLVM_DEBUGINFO_DWARF_DWARFUNIT_H
  11
  12 #include "llvm/ADT/Optional.h"
  13 #include "llvm/ADT/STLExtras.h"
  14 #include "llvm/ADT/SmallVector.h"
  15 #include "llvm/ADT/StringRef.h"
  16 #include "llvm/ADT/iterator_range.h"
  17 #include "llvm/BinaryFormat/Dwarf.h"
  18 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
  19 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
  20 #include "llvm/DebugInfo/DWARF/DWARFDebugRnglists.h"
  21 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
  22 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
  23 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
  24 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
  25 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
  26 #include "llvm/Support/DataExtractor.h"
  27 #include <algorithm>
  28 #include <cassert>
  29 #include <cstddef>
  30 #include <cstdint>
  31 #include <map>
  32 #include <memory>
  33 #include <utility>
  34 #include <vector>
  35
  36 namespace llvm {
  37
  38 class DWARFAbbreviationDeclarationSet;
  39 class DWARFContext;
  40 class DWARFDebugAbbrev;
  41 class DWARFUnit;
  42
  43 /// Base class describing the header of any kind of "unit."  Some information
  44 /// is specific to certain unit types.  We separate this class out so we can
  45 /// parse the header before deciding what specific kind of unit to construct.
  46 class DWARFUnitHeader {
  47   // Offset within section.
  48   uint64_t Offset = 0;
  49   // Version, address size, and DWARF format.
  50   dwarf::FormParams FormParams;
  51   uint64_t Length = 0;
  52   uint64_t AbbrOffset = 0;
  53
  54   // For DWO units only.
  55   const DWARFUnitIndex::Entry *IndexEntry = nullptr;
  56
  57   // For type units only.
  58   uint64_t TypeHash = 0;
  59   uint64_t TypeOffset = 0;
  60
  61   // For v5 split or skeleton compile units only.
  62   Optional<uint64_t> DWOId;
  63
  64   // Unit type as parsed, or derived from the section kind.
  65   uint8_t UnitType = 0;
  66
  67   // Size as parsed. uint8_t for compactness.
  68   uint8_t Size = 0;
  69
  70 public:
  71   /// Parse a unit header from \p debug_info starting at \p offset_ptr.
  72   bool extract(DWARFContext &Context, const DWARFDataExtractor &debug_info,
  73                uint64_t *offset_ptr, DWARFSectionKind Kind = DW_SECT_INFO,
  74                const DWARFUnitIndex *Index = nullptr,
  75                const DWARFUnitIndex::Entry *Entry = nullptr);
  76   uint64_t getOffset() const { return Offset; }
  77   const dwarf::FormParams &getFormParams() const { return FormParams; }
  78   uint16_t getVersion() const { return FormParams.Version; }
  79   dwarf::DwarfFormat getFormat() const { return FormParams.Format; }
  80   uint8_t getAddressByteSize() const { return FormParams.AddrSize; }
  81   uint8_t getRefAddrByteSize() const { return FormParams.getRefAddrByteSize(); }
  82   uint8_t getDwarfOffsetByteSize() const {
  83     return FormParams.getDwarfOffsetByteSize();
  84   }
  85   uint64_t getLength() const { return Length; }
  86   uint64_t getAbbrOffset() const { return AbbrOffset; }
  87   Optional<uint64_t> getDWOId() const { return DWOId; }
  88   void setDWOId(uint64_t Id) {
  89     assert((!DWOId || *DWOId == Id) && "setting DWOId to a different value");
  90     DWOId = Id;
  91   }
  92   const DWARFUnitIndex::Entry *getIndexEntry() const { return IndexEntry; }
  93   uint64_t getTypeHash() const { return TypeHash; }
  94   uint64_t getTypeOffset() const { return TypeOffset; }
  95   uint8_t getUnitType() const { return UnitType; }
  96   bool isTypeUnit() const {
  97     return UnitType == dwarf::DW_UT_type || UnitType == dwarf::DW_UT_split_type;
  98   }
  99   uint8_t getSize() const { return Size; }
 100   uint8_t getUnitLengthFieldByteSize() const {
 101     return dwarf::getUnitLengthFieldByteSize(FormParams.Format);
 102   }
 103   uint64_t getNextUnitOffset() const {
 104     return Offset + Length + getUnitLengthFieldByteSize();
 105   }
 106 };
 107
 108 const DWARFUnitIndex &getDWARFUnitIndex(DWARFContext &Context,
 109                                         DWARFSectionKind Kind);
 110
 111 /// Describe a collection of units. Intended to hold all units either from
 112 /// .debug_info and .debug_types, or from .debug_info.dwo and .debug_types.dwo.
 113 class DWARFUnitVector final : public SmallVector<std::unique_ptr<DWARFUnit>, 1> {
 114   std::function<std::unique_ptr<DWARFUnit>(uint64_t, DWARFSectionKind,
 115                                            const DWARFSection *,
 116                                            const DWARFUnitIndex::Entry *)>
 117       Parser;
 118   int NumInfoUnits = -1;
 119
 120 public:
 121   using UnitVector = SmallVectorImpl<std::unique_ptr<DWARFUnit>>;
 122   using iterator = typename UnitVector::iterator;
 123   using iterator_range = llvm::iterator_range<typename UnitVector::iterator>;
 124
 125   DWARFUnit *getUnitForOffset(uint64_t Offset) const;
 126   DWARFUnit *getUnitForIndexEntry(const DWARFUnitIndex::Entry &E);
 127
 128   /// Read units from a .debug_info or .debug_types section.  Calls made
 129   /// before finishedInfoUnits() are assumed to be for .debug_info sections,
 130   /// calls after finishedInfoUnits() are for .debug_types sections.  Caller
 131   /// must not mix calls to addUnitsForSection and addUnitsForDWOSection.
 132   void addUnitsForSection(DWARFContext &C, const DWARFSection &Section,
 133                           DWARFSectionKind SectionKind);
 134   /// Read units from a .debug_info.dwo or .debug_types.dwo section.  Calls
 135   /// made before finishedInfoUnits() are assumed to be for .debug_info.dwo
 136   /// sections, calls after finishedInfoUnits() are for .debug_types.dwo
 137   /// sections.  Caller must not mix calls to addUnitsForSection and
 138   /// addUnitsForDWOSection.
 139   void addUnitsForDWOSection(DWARFContext &C, const DWARFSection &DWOSection,
 140                              DWARFSectionKind SectionKind, bool Lazy = false);
 141
 142   /// Add an existing DWARFUnit to this UnitVector. This is used by the DWARF
 143   /// verifier to process unit separately.
 144   DWARFUnit *addUnit(std::unique_ptr<DWARFUnit> Unit);
 145
 146   /// Returns number of all units held by this instance.
 147   unsigned getNumUnits() const { return size(); }
 148   /// Returns number of units from all .debug_info[.dwo] sections.
 149   unsigned getNumInfoUnits() const {
 150     return NumInfoUnits == -1 ? size() : NumInfoUnits;
 151   }
 152   /// Returns number of units from all .debug_types[.dwo] sections.
 153   unsigned getNumTypesUnits() const { return size() - NumInfoUnits; }
 154   /// Indicate that parsing .debug_info[.dwo] is done, and remaining units
 155   /// will be from .debug_types[.dwo].
 156   void finishedInfoUnits() { NumInfoUnits = size(); }
 157
 158 private:
 159   void addUnitsImpl(DWARFContext &Context, const DWARFObject &Obj,
 160                     const DWARFSection &Section, const DWARFDebugAbbrev *DA,
 161                     const DWARFSection *RS, const DWARFSection *LocSection,
 162                     StringRef SS, const DWARFSection &SOS,
 163                     const DWARFSection *AOS, const DWARFSection &LS, bool LE,
 164                     bool IsDWO, bool Lazy, DWARFSectionKind SectionKind);
 165 };
 166
 167 /// Represents base address of the CU.
 168 /// Represents a unit's contribution to the string offsets table.
 169 struct StrOffsetsContributionDescriptor {
 170   uint64_t Base = 0;
 171   /// The contribution size not including the header.
 172   uint64_t Size = 0;
 173   /// Format and version.
 174   dwarf::FormParams FormParams = {0, 0, dwarf::DwarfFormat::DWARF32};
 175
 176   StrOffsetsContributionDescriptor(uint64_t Base, uint64_t Size,
 177                                    uint8_t Version, dwarf::DwarfFormat Format)
 178       : Base(Base), Size(Size), FormParams({Version, 0, Format}) {}
 179   StrOffsetsContributionDescriptor() = default;
 180
 181   uint8_t getVersion() const { return FormParams.Version; }
 182   dwarf::DwarfFormat getFormat() const { return FormParams.Format; }
 183   uint8_t getDwarfOffsetByteSize() const {
 184     return FormParams.getDwarfOffsetByteSize();
 185   }
 186   /// Determine whether a contribution to the string offsets table is
 187   /// consistent with the relevant section size and that its length is
 188   /// a multiple of the size of one of its entries.
 189   Expected<StrOffsetsContributionDescriptor>
 190   validateContributionSize(DWARFDataExtractor &DA);
 191 };
 192
 193 class DWARFUnit {
 194   DWARFContext &Context;
 195   /// Section containing this DWARFUnit.
 196   const DWARFSection &InfoSection;
 197
 198   DWARFUnitHeader Header;
 199   const DWARFDebugAbbrev *Abbrev;
 200   const DWARFSection *RangeSection;
 201   uint64_t RangeSectionBase;
 202   /// We either keep track of the location list section or its data, depending
 203   /// on whether we are handling a split DWARF section or not.
 204   union {
 205     const DWARFSection *LocSection;
 206     StringRef LocSectionData;
 207   };
 208   const DWARFSection &LineSection;
 209   StringRef StringSection;
 210   const DWARFSection &StringOffsetSection;
 211   const DWARFSection *AddrOffsetSection;
 212   uint32_t AddrOffsetSectionBase = 0;
 213   bool isLittleEndian;
 214   bool IsDWO;
 215   const DWARFUnitVector &UnitVector;
 216
 217   /// Start, length, and DWARF format of the unit's contribution to the string
 218   /// offsets table (DWARF v5).
 219   Optional<StrOffsetsContributionDescriptor> StringOffsetsTableContribution;
 220
 221   /// A table of range lists (DWARF v5 and later).
 222   Optional<DWARFDebugRnglistTable> RngListTable;
 223
 224   mutable const DWARFAbbreviationDeclarationSet *Abbrevs;
 225   llvm::Optional<object::SectionedAddress> BaseAddr;
 226   /// The compile unit debug information entry items.
 227   std::vector<DWARFDebugInfoEntry> DieArray;
 228
 229   /// Map from range's start address to end address and corresponding DIE.
 230   /// IntervalMap does not support range removal, as a result, we use the
 231   /// std::map::upper_bound for address range lookup.
 232   std::map<uint64_t, std::pair<uint64_t, DWARFDie>> AddrDieMap;
 233
 234   using die_iterator_range =
 235       iterator_range<std::vector<DWARFDebugInfoEntry>::iterator>;
 236
 237   std::shared_ptr<DWARFUnit> DWO;
 238
 239   uint32_t getDIEIndex(const DWARFDebugInfoEntry *Die) {
 240     auto First = DieArray.data();
 241     assert(Die >= First && Die < First + DieArray.size());
 242     return Die - First;
 243   }
 244
 245 protected:
 246   const DWARFUnitHeader &getHeader() const { return Header; }
 247
 248   /// Size in bytes of the parsed unit header.
 249   uint32_t getHeaderSize() const { return Header.getSize(); }
 250
 251   /// Find the unit's contribution to the string offsets table and determine its
 252   /// length and form. The given offset is expected to be derived from the unit
 253   /// DIE's DW_AT_str_offsets_base attribute.
 254   Expected<Optional<StrOffsetsContributionDescriptor>>
 255   determineStringOffsetsTableContribution(DWARFDataExtractor &DA);
 256
 257   /// Find the unit's contribution to the string offsets table and determine its
 258   /// length and form. The given offset is expected to be 0 in a dwo file or,
 259   /// in a dwp file, the start of the unit's contribution to the string offsets
 260   /// table section (as determined by the index table).
 261   Expected<Optional<StrOffsetsContributionDescriptor>>
 262   determineStringOffsetsTableContributionDWO(DWARFDataExtractor &DA);
 263
 264 public:
 265   DWARFUnit(DWARFContext &Context, const DWARFSection &Section,
 266             const DWARFUnitHeader &Header, const DWARFDebugAbbrev *DA,
 267             const DWARFSection *RS, const DWARFSection *LocSection,
 268             StringRef SS, const DWARFSection &SOS, const DWARFSection *AOS,
 269             const DWARFSection &LS, bool LE, bool IsDWO,
 270             const DWARFUnitVector &UnitVector);
 271
 272   virtual ~DWARFUnit();
 273
 274   bool isDWOUnit() const { return IsDWO; }
 275   DWARFContext& getContext() const { return Context; }
 276   const DWARFSection &getInfoSection() const { return InfoSection; }
 277   const DWARFSection *getLocSection() const { return LocSection; }
 278   StringRef getLocSectionData() const { return LocSectionData; }
 279   uint64_t getOffset() const { return Header.getOffset(); }
 280   const dwarf::FormParams &getFormParams() const {
 281     return Header.getFormParams();
 282   }
 283   uint16_t getVersion() const { return Header.getVersion(); }
 284   uint8_t getAddressByteSize() const { return Header.getAddressByteSize(); }
 285   uint8_t getRefAddrByteSize() const { return Header.getRefAddrByteSize(); }
 286   uint8_t getDwarfOffsetByteSize() const {
 287     return Header.getDwarfOffsetByteSize();
 288   }
 289   uint64_t getLength() const { return Header.getLength(); }
 290   uint8_t getUnitType() const { return Header.getUnitType(); }
 291   bool isTypeUnit() const { return Header.isTypeUnit(); }
 292   uint64_t getNextUnitOffset() const { return Header.getNextUnitOffset(); }
 293   const DWARFSection &getLineSection() const { return LineSection; }
 294   StringRef getStringSection() const { return StringSection; }
 295   const DWARFSection &getStringOffsetSection() const {
 296     return StringOffsetSection;
 297   }
 298
 299   void setAddrOffsetSection(const DWARFSection *AOS, uint32_t Base) {
 300     AddrOffsetSection = AOS;
 301     AddrOffsetSectionBase = Base;
 302   }
 303
 304   /// Recursively update address to Die map.
 305   void updateAddressDieMap(DWARFDie Die);
 306
 307   void setRangesSection(const DWARFSection *RS, uint64_t Base) {
 308     RangeSection = RS;
 309     RangeSectionBase = Base;
 310   }
 311
 312   Optional<object::SectionedAddress>
 313   getAddrOffsetSectionItem(uint32_t Index) const;
 314   Optional<uint64_t> getStringOffsetSectionItem(uint32_t Index) const;
 315
 316   DWARFDataExtractor getDebugInfoExtractor() const;
 317
 318   DataExtractor getStringExtractor() const {
 319     return DataExtractor(StringSection, false, 0);
 320   }
 321
 322   /// Extract the range list referenced by this compile unit from the
 323   /// .debug_ranges section. If the extraction is unsuccessful, an error
 324   /// is returned. Successful extraction requires that the compile unit
 325   /// has already been extracted.
 326   Error extractRangeList(uint64_t RangeListOffset,
 327                          DWARFDebugRangeList &RangeList) const;
 328   void clear();
 329
 330   const Optional<StrOffsetsContributionDescriptor> &
 331   getStringOffsetsTableContribution() const {
 332     return StringOffsetsTableContribution;
 333   }
 334
 335   uint8_t getDwarfStringOffsetsByteSize() const {
 336     assert(StringOffsetsTableContribution);
 337     return StringOffsetsTableContribution->getDwarfOffsetByteSize();
 338   }
 339
 340   uint64_t getStringOffsetsBase() const {
 341     assert(StringOffsetsTableContribution);
 342     return StringOffsetsTableContribution->Base;
 343   }
 344
 345   const DWARFAbbreviationDeclarationSet *getAbbreviations() const;
 346
 347   static bool isMatchingUnitTypeAndTag(uint8_t UnitType, dwarf::Tag Tag) {
 348     switch (UnitType) {
 349     case dwarf::DW_UT_compile:
 350       return Tag == dwarf::DW_TAG_compile_unit;
 351     case dwarf::DW_UT_type:
 352       return Tag == dwarf::DW_TAG_type_unit;
 353     case dwarf::DW_UT_partial:
 354       return Tag == dwarf::DW_TAG_partial_unit;
 355     case dwarf::DW_UT_skeleton:
 356       return Tag == dwarf::DW_TAG_skeleton_unit;
 357     case dwarf::DW_UT_split_compile:
 358     case dwarf::DW_UT_split_type:
 359       return dwarf::isUnitType(Tag);
 360     }
 361     return false;
 362   }
 363
 364   /// Return the number of bytes for the header of a unit of
 365   /// UnitType type.
 366   ///
 367   /// This function must be called with a valid unit type which in
 368   /// DWARF5 is defined as one of the following six types.
 369   static uint32_t getDWARF5HeaderSize(uint8_t UnitType) {
 370     switch (UnitType) {
 371     case dwarf::DW_UT_compile:
 372     case dwarf::DW_UT_partial:
 373       return 12;
 374     case dwarf::DW_UT_skeleton:
 375     case dwarf::DW_UT_split_compile:
 376       return 20;
 377     case dwarf::DW_UT_type:
 378     case dwarf::DW_UT_split_type:
 379       return 24;
 380     }
 381     llvm_unreachable("Invalid UnitType.");
 382   }
 383
 384   llvm::Optional<object::SectionedAddress> getBaseAddress();
 385
 386   DWARFDie getUnitDIE(bool ExtractUnitDIEOnly = true) {
 387     extractDIEsIfNeeded(ExtractUnitDIEOnly);
 388     if (DieArray.empty())
 389       return DWARFDie();
 390     return DWARFDie(this, &DieArray[0]);
 391   }
 392
 393   DWARFDie getNonSkeletonUnitDIE(bool ExtractUnitDIEOnly = true) {
 394     parseDWO();
 395     if (DWO)
 396       return DWO->getUnitDIE(ExtractUnitDIEOnly);
 397     return getUnitDIE(ExtractUnitDIEOnly);
 398   }
 399
 400   const char *getCompilationDir();
 401   Optional<uint64_t> getDWOId() {
 402     extractDIEsIfNeeded(/*CUDieOnly*/ true);
 403     return getHeader().getDWOId();
 404   }
 405   void setDWOId(uint64_t NewID) { Header.setDWOId(NewID); }
 406
 407   /// Return a vector of address ranges resulting from a (possibly encoded)
 408   /// range list starting at a given offset in the appropriate ranges section.
 409   Expected<DWARFAddressRangesVector> findRnglistFromOffset(uint64_t Offset);
 410
 411   /// Return a vector of address ranges retrieved from an encoded range
 412   /// list whose offset is found via a table lookup given an index (DWARF v5
 413   /// and later).
 414   Expected<DWARFAddressRangesVector> findRnglistFromIndex(uint32_t Index);
 415
 416   /// Return a rangelist's offset based on an index. The index designates
 417   /// an entry in the rangelist table's offset array and is supplied by
 418   /// DW_FORM_rnglistx.
 419   Optional<uint64_t> getRnglistOffset(uint32_t Index) {
 420     if (RngListTable)
 421       return RngListTable->getOffsetEntry(Index);
 422     return None;
 423   }
 424
 425   Expected<DWARFAddressRangesVector> collectAddressRanges();
 426
 427   /// Returns subprogram DIE with address range encompassing the provided
 428   /// address. The pointer is alive as long as parsed compile unit DIEs are not
 429   /// cleared.
 430   DWARFDie getSubroutineForAddress(uint64_t Address);
 431
 432   /// getInlinedChainForAddress - fetches inlined chain for a given address.
 433   /// Returns empty chain if there is no subprogram containing address. The
 434   /// chain is valid as long as parsed compile unit DIEs are not cleared.
 435   void getInlinedChainForAddress(uint64_t Address,
 436                                  SmallVectorImpl<DWARFDie> &InlinedChain);
 437
 438   /// Return the DWARFUnitVector containing this unit.
 439   const DWARFUnitVector &getUnitVector() const { return UnitVector; }
 440
 441   /// Returns the number of DIEs in the unit. Parses the unit
 442   /// if necessary.
 443   unsigned getNumDIEs() {
 444     extractDIEsIfNeeded(false);
 445     return DieArray.size();
 446   }
 447
 448   /// Return the index of a DIE inside the unit's DIE vector.
 449   ///
 450   /// It is illegal to call this method with a DIE that hasn't be
 451   /// created by this unit. In other word, it's illegal to call this
 452   /// method on a DIE that isn't accessible by following
 453   /// children/sibling links starting from this unit's getUnitDIE().
 454   uint32_t getDIEIndex(const DWARFDie &D) {
 455     return getDIEIndex(D.getDebugInfoEntry());
 456   }
 457
 458   /// Return the DIE object at the given index.
 459   DWARFDie getDIEAtIndex(unsigned Index) {
 460     assert(Index < DieArray.size());
 461     return DWARFDie(this, &DieArray[Index]);
 462   }
 463
 464   DWARFDie getParent(const DWARFDebugInfoEntry *Die);
 465   DWARFDie getSibling(const DWARFDebugInfoEntry *Die);
 466   DWARFDie getPreviousSibling(const DWARFDebugInfoEntry *Die);
 467   DWARFDie getFirstChild(const DWARFDebugInfoEntry *Die);
 468   DWARFDie getLastChild(const DWARFDebugInfoEntry *Die);
 469
 470   /// Return the DIE object for a given offset inside the
 471   /// unit's DIE vector.
 472   ///
 473   /// The unit needs to have its DIEs extracted for this method to work.
 474   DWARFDie getDIEForOffset(uint64_t Offset) {
 475     extractDIEsIfNeeded(false);
 476     assert(!DieArray.empty());
 477     auto It =
 478         llvm::partition_point(DieArray, [=](const DWARFDebugInfoEntry &DIE) {
 479           return DIE.getOffset() < Offset;
 480         });
 481     if (It != DieArray.end() && It->getOffset() == Offset)
 482       return DWARFDie(this, &*It);
 483     return DWARFDie();
 484   }
 485
 486   uint32_t getLineTableOffset() const {
 487     if (auto IndexEntry = Header.getIndexEntry())
 488       if (const auto *Contrib = IndexEntry->getOffset(DW_SECT_LINE))
 489         return Contrib->Offset;
 490     return 0;
 491   }
 492
 493   die_iterator_range dies() {
 494     extractDIEsIfNeeded(false);
 495     return die_iterator_range(DieArray.begin(), DieArray.end());
 496   }
 497
 498   virtual void dump(raw_ostream &OS, DIDumpOptions DumpOpts) = 0;
 499
 500   Error tryExtractDIEsIfNeeded(bool CUDieOnly);
 501
 502 private:
 503   /// Size in bytes of the .debug_info data associated with this compile unit.
 504   size_t getDebugInfoSize() const {
 505     return Header.getLength() + Header.getUnitLengthFieldByteSize() -
 506            getHeaderSize();
 507   }
 508
 509   /// extractDIEsIfNeeded - Parses a compile unit and indexes its DIEs if it
 510   /// hasn't already been done
 511   void extractDIEsIfNeeded(bool CUDieOnly);
 512
 513   /// extractDIEsToVector - Appends all parsed DIEs to a vector.
 514   void extractDIEsToVector(bool AppendCUDie, bool AppendNonCUDIEs,
 515                            std::vector<DWARFDebugInfoEntry> &DIEs) const;
 516
 517   /// clearDIEs - Clear parsed DIEs to keep memory usage low.
 518   void clearDIEs(bool KeepCUDie);
 519
 520   /// parseDWO - Parses .dwo file for current compile unit. Returns true if
 521   /// it was actually constructed.
 522   bool parseDWO();
 523 };
 524
 525 } // end namespace llvm
 526
 527 #endif // LLVM_DEBUGINFO_DWARF_DWARFUNIT_H