Use delegation instead of inheritance

[• rafael]

Summary

This changes DwarfContext to delegate to DwarfObj instead of having pure virtual methods.

With this DwarfContextInMemory is a trivial class that uses a new implementation of a DwarfObj which can be in a .cpp file.

This is more verbose than I was hopping for, but does allow lld to just implement a DwarfObj. Let me know if you think this is too verbose and I can subclass DwarfContext in lld instead.

[• rafael]

Use dummy values instead of unreachable.

[dblaikie]

Might be helpful to have a bit of a summary about what's changing here, separate from looking at all the source manually - what operations stayed in DWARFContext{,InMemory} versus those that moved out into DWARFObject?

Do all the operations need wrappers in DWARFContext, or could many of those be removed because they're probably only used internally within DWARFContext & could be replaced with "Obj->thing" instead? (though that's more refactoring/churn, I realize)

include/llvm/DebugInfo/DWARF/DWARFContext.h

56

Why do these all need default implementations? Guessing there's a reason they're not pure virtual? Though it seems like it'd make using this class more difficult if there are implicit contracts about which subset of operations are implemented and which ones are not?

[• rafael]

Inline trivial functions.

[dblaikie]

Generally looks good to me - few bits to be tidied up, etc.
Haven't looked meticulously closely at the bits of code that moved around, but I assume there wasn't anything particularly novel there.

Might be worth waiting for a few more eyes, but doesn't seem too crazy.

include/llvm/DebugInfo/DWARF/DWARFContext.h

56

Pull this out into a separate file, probably? (& maybe even pull DWARFObjInMemory into a separate file too - we do end up with some pretty big/glommy headers)

(no need to do this pre-emptively, if you want to wait to see how the design choices shake out)

60

default?

91–95

Given that DWARFSection is now only StringRef - why not return by value & return "" like the rest? (& I sitll don't know whether DWARFSection needs to exist at all if it's only a wrapper around StringRef - it makes this whole class look a bit random/arbitrary between some functions returning StringRef for a section, and others returning const DWARFSection&)

156

Why is this non-owning and DWARFContextInMemory owning?

Are tehre any other implementations of DWARFContext (other than DWARFContextInMemory) or should we just do away with the abstraction if it's unused?

include/llvm/DebugInfo/DWARF/DWARFSection.h

18–24

What's the reason for this split? Is DWARFSection much use if it's a straight up wrapper around StringRef?

[• rafael]

Move some code to another header.

[• rafael]

Move DWARFContextInMemory to a .cpp file I will completely delete it tomorrow.

[• rafael]

Delete DWARFContextInMemory.

[• rafael]

Rebased.

[dblaikie]

include/llvm/DebugInfo/DWARF/DWARFObj.h

24

I'd wonder about the name - DWARFObject? DWARFObjectSections?

unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp

2186

"*Obj.get()" can probably be "*Obj"? (similarly above)

[• espindola]

308543

include/llvm/DebugInfo/DWARF/DWARFContext.h

 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugAranges.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFGdbIndex.h"
+#include "llvm/DebugInfo/DWARF/DWARFObj.h"
 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
 #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
 #include "llvm/Object/Binary.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Host.h"
 #include <cstdint>
 #include <deque>
 #include <map>
 #include <memory>
 
 namespace llvm {
 
 class DataExtractor;
 class MemoryBuffer;
 class raw_ostream;
 
+/// Used as a return value for a error callback passed to DWARF context.
+/// Callback should return Halt if client application wants to stop
+/// object parsing, or should return Continue otherwise.
+enum class ErrorPolicy { Halt, Continue };
+
 /// DWARFContext
 /// This data structure is the top level entity that deals with dwarf debug
-/// information parsing. The actual data is supplied through pure virtual
-/// methods that a concrete implementation provides.
+/// information parsing. The actual data is supplied through DWARFObj.
 class DWARFContext : public DIContext {
   DWARFUnitSection<DWARFCompileUnit> CUs;
   std::deque<DWARFUnitSection<DWARFTypeUnit>> TUs;
   std::unique_ptr<DWARFUnitIndex> CUIndex;
   std::unique_ptr<DWARFGdbIndex> GdbIndex;
   std::unique_ptr<DWARFUnitIndex> TUIndex;
   std::unique_ptr<DWARFDebugAbbrev> Abbrev;
   std::unique_ptr<DWARFDebugLoc> Loc;
   std::unique_ptr<DWARFDebugAranges> Aranges;
   std::unique_ptr<DWARFDebugLine> Line;
   std::unique_ptr<DWARFDebugFrame> DebugFrame;
   std::unique_ptr<DWARFDebugFrame> EHFrame;
class DWARFContext : public DIContext {
   StringMap<std::weak_ptr<DWOFile>> DWOFiles;
   std::weak_ptr<DWOFile> DWP;
   bool CheckedForDWP = false;
 
   /// Read compile units from the debug_info section (if necessary)
   /// and store them in CUs.
   void parseCompileUnits();
 
   /// Read type units from the debug_types sections (if necessary)
   /// and store them in TUs.
   void parseTypeUnits();
 
   /// Read compile units from the debug_info.dwo section (if necessary)
   /// and store them in DWOCUs.
   void parseDWOCompileUnits();
 
   /// Read type units from the debug_types.dwo section (if necessary)
   /// and store them in DWOTUs.
   void parseDWOTypeUnits();
 
+protected:
+  std::unique_ptr<const DWARFObj> DObj;
+
 public:
-  DWARFContext() : DIContext(CK_DWARF) {}
+  DWARFContext(std::unique_ptr<const DWARFObj> DObj)
+      : DIContext(CK_DWARF), DObj(std::move(DObj)) {}
   DWARFContext(DWARFContext &) = delete;
   DWARFContext &operator=(DWARFContext &) = delete;
 
+  const DWARFObj &getDWARFObj() const { return *DObj; }
+
   static bool classof(const DIContext *DICtx) {
     return DICtx->getKind() == CK_DWARF;
   }
 
   void dump(raw_ostream &OS, DIDumpOptions DumpOpts) override;
 
   bool verify(raw_ostream &OS, DIDumpType DumpType = DIDT_All) override;
 
public:
   }
 
   /// Get the number of compile units in this context.
   unsigned getNumCompileUnits() {
     parseCompileUnits();
     return CUs.size();
   }
 
   /// Get the number of compile units in this context.
   unsigned getNumTypeUnits() {
     parseTypeUnits();
     return TUs.size();
   }
 
   /// Get the number of compile units in the DWO context.
   unsigned getNumDWOCompileUnits() {
     parseDWOCompileUnits();
public:
 
   DILineInfo getLineInfoForAddress(uint64_t Address,
       DILineInfoSpecifier Specifier = DILineInfoSpecifier()) override;
   DILineInfoTable getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
       DILineInfoSpecifier Specifier = DILineInfoSpecifier()) override;
   DIInliningInfo getInliningInfoForAddress(uint64_t Address,
       DILineInfoSpecifier Specifier = DILineInfoSpecifier()) override;
 
-  virtual StringRef getFileName() const = 0;
-  virtual bool isLittleEndian() const = 0;
-  virtual uint8_t getAddressSize() const = 0;
-  virtual const DWARFSection &getInfoSection() = 0;
-  virtual void forEachTypesSections(function_ref<void(DWARFSection &)> F) = 0;
-  virtual StringRef getAbbrevSection() = 0;
-  virtual const DWARFSection &getLocSection() = 0;
-  virtual StringRef getARangeSection() = 0;
-  virtual StringRef getDebugFrameSection() = 0;
-  virtual StringRef getEHFrameSection() = 0;
-  virtual const DWARFSection &getLineSection() = 0;
-  virtual StringRef getStringSection() = 0;
-  virtual const DWARFSection& getRangeSection() = 0;
-  virtual StringRef getMacinfoSection() = 0;
-  virtual StringRef getPubNamesSection() = 0;
-  virtual StringRef getPubTypesSection() = 0;
-  virtual StringRef getGnuPubNamesSection() = 0;
-  virtual StringRef getGnuPubTypesSection() = 0;
-
-  /// DWARF v5
-  /// @{
-  virtual const DWARFSection &getStringOffsetSection() = 0;
-  /// @}
-
-  // Sections for DWARF5 split dwarf proposal.
-  virtual const DWARFSection &getInfoDWOSection() = 0;
-  virtual void
-  forEachTypesDWOSections(function_ref<void(DWARFSection &)> F) = 0;
-  virtual StringRef getAbbrevDWOSection() = 0;
-  virtual const DWARFSection &getLineDWOSection() = 0;
-  virtual const DWARFSection &getLocDWOSection() = 0;
-  virtual StringRef getStringDWOSection() = 0;
-  virtual const DWARFSection &getStringOffsetDWOSection() = 0;
-  virtual const DWARFSection &getRangeDWOSection() = 0;
-  virtual const DWARFSection &getAddrSection() = 0;
-  virtual const DWARFSection& getAppleNamesSection() = 0;
-  virtual const DWARFSection& getAppleTypesSection() = 0;
-  virtual const DWARFSection& getAppleNamespacesSection() = 0;
-  virtual const DWARFSection& getAppleObjCSection() = 0;
-  virtual StringRef getCUIndexSection() = 0;
-  virtual StringRef getGdbIndexSection() = 0;
-  virtual StringRef getTUIndexSection() = 0;
-
+  bool isLittleEndian() const { return DObj->isLittleEndian(); }
   static bool isSupportedVersion(unsigned version) {
     return version == 2 || version == 3 || version == 4 || version == 5;
   }
 
   std::shared_ptr<DWARFContext> getDWOContext(StringRef AbsolutePath);
 
+  /// Function used to handle default error reporting policy. Prints a error
+  /// message and returns Continue, so DWARF context ignores the error.
+  static ErrorPolicy defaultErrorHandler(Error E);
+  static std::unique_ptr<DWARFContext>
+  create(const object::ObjectFile &Obj, const LoadedObjectInfo *L = nullptr,
+         function_ref<ErrorPolicy(Error)> HandleError = defaultErrorHandler);
+
+  static std::unique_ptr<DWARFContext>
+  create(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
+         uint8_t AddrSize, bool isLittleEndian = sys::IsLittleEndianHost);
+
 private:
   /// Return the compile unit that includes an offset (relative to .debug_info).
   DWARFCompileUnit *getCompileUnitForOffset(uint32_t Offset);
 
   /// Return the compile unit which contains instruction with provided
   /// address.
   DWARFCompileUnit *getCompileUnitForAddress(uint64_t Address);
 };
 
-/// Used as a return value for a error callback passed to DWARF context.
-/// Callback should return Halt if client application wants to stop
-/// object parsing, or should return Continue otherwise.
-enum class ErrorPolicy { Halt, Continue };
-
-/// DWARFContextInMemory is the simplest possible implementation of a
-/// DWARFContext. It assumes all content is available in memory and stores
-/// pointers to it.
-class DWARFContextInMemory : public DWARFContext {
-  virtual void anchor();
-
-  using TypeSectionMap = MapVector<object::SectionRef, DWARFSection,
-                                   std::map<object::SectionRef, unsigned>>;
-
-  StringRef FileName;
-  bool IsLittleEndian;
-  uint8_t AddressSize;
-  DWARFSection InfoSection;
-  TypeSectionMap TypesSections;
-  StringRef AbbrevSection;
-  DWARFSection LocSection;
-  StringRef ARangeSection;
-  StringRef DebugFrameSection;
-  StringRef EHFrameSection;
-  DWARFSection LineSection;
-  StringRef StringSection;
-  DWARFSection RangeSection;
-  StringRef MacinfoSection;
-  StringRef PubNamesSection;
-  StringRef PubTypesSection;
-  StringRef GnuPubNamesSection;
-  StringRef GnuPubTypesSection;
-
-  /// DWARF v5
-  /// @{
-  DWARFSection StringOffsetSection;
-  /// @}
-
-  // Sections for DWARF5 split dwarf proposal.
-  DWARFSection InfoDWOSection;
-  TypeSectionMap TypesDWOSections;
-  StringRef AbbrevDWOSection;
-  DWARFSection LineDWOSection;
-  DWARFSection LocDWOSection;
-  StringRef StringDWOSection;
-  DWARFSection StringOffsetDWOSection;
-  DWARFSection RangeDWOSection;
-  DWARFSection AddrSection;
-  DWARFSection AppleNamesSection;
-  DWARFSection AppleTypesSection;
-  DWARFSection AppleNamespacesSection;
-  DWARFSection AppleObjCSection;
-  StringRef CUIndexSection;
-  StringRef GdbIndexSection;
-  StringRef TUIndexSection;
-
-  SmallVector<SmallString<32>, 4> UncompressedSections;
-
-  DWARFSection *mapNameToDWARFSection(StringRef Name);
-  StringRef *mapSectionToMember(StringRef Name);
-
-  /// If Sec is compressed section, decompresses and updates its contents
-  /// provided by Data. Otherwise leaves it unchanged.
-  Error maybeDecompress(const object::SectionRef &Sec, StringRef Name,
-                        StringRef &Data);
-
-  /// Function used to handle default error reporting policy. Prints a error
-  /// message and returns Continue, so DWARF context ignores the error.
-  static ErrorPolicy defaultErrorHandler(Error E);
-
-public:
-  DWARFContextInMemory(
-      const object::ObjectFile &Obj, const LoadedObjectInfo *L = nullptr,
-      function_ref<ErrorPolicy(Error)> HandleError = defaultErrorHandler);
-
-  DWARFContextInMemory(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
-                       uint8_t AddrSize,
-                       bool isLittleEndian = sys::IsLittleEndianHost);
-
-  StringRef getFileName() const override { return FileName; }
-  bool isLittleEndian() const override { return IsLittleEndian; }
-  uint8_t getAddressSize() const override { return AddressSize; }
-  const DWARFSection &getInfoSection() override { return InfoSection; }
-  void forEachTypesSections(function_ref<void(DWARFSection &)> F) override {
-    for (auto &P : TypesSections)
-      F(P.second);
-  }
-  StringRef getAbbrevSection() override { return AbbrevSection; }
-  const DWARFSection &getLocSection() override { return LocSection; }
-  StringRef getARangeSection() override { return ARangeSection; }
-  StringRef getDebugFrameSection() override { return DebugFrameSection; }
-  StringRef getEHFrameSection() override { return EHFrameSection; }
-  const DWARFSection &getLineSection() override { return LineSection; }
-  StringRef getStringSection() override { return StringSection; }
-  const DWARFSection &getRangeSection() override { return RangeSection; }
-  StringRef getMacinfoSection() override { return MacinfoSection; }
-  StringRef getPubNamesSection() override { return PubNamesSection; }
-  StringRef getPubTypesSection() override { return PubTypesSection; }
-  StringRef getGnuPubNamesSection() override { return GnuPubNamesSection; }
-  StringRef getGnuPubTypesSection() override { return GnuPubTypesSection; }
-  const DWARFSection& getAppleNamesSection() override { return AppleNamesSection; }
-  const DWARFSection& getAppleTypesSection() override { return AppleTypesSection; }
-  const DWARFSection& getAppleNamespacesSection() override { return AppleNamespacesSection; }
-  const DWARFSection& getAppleObjCSection() override { return AppleObjCSection; }
-
-  // DWARF v5
-  const DWARFSection &getStringOffsetSection() override {
-    return StringOffsetSection;
-  }
-
-  // Sections for DWARF5 split dwarf proposal.
-  const DWARFSection &getInfoDWOSection() override { return InfoDWOSection; }
-
-  void forEachTypesDWOSections(function_ref<void(DWARFSection &)> F) override {
-    for (auto &P : TypesDWOSections)
-      F(P.second);
-  }
-
-  StringRef getAbbrevDWOSection() override { return AbbrevDWOSection; }
-  const DWARFSection &getLineDWOSection() override { return LineDWOSection; }
-  const DWARFSection &getLocDWOSection() override { return LocDWOSection; }
-  StringRef getStringDWOSection() override { return StringDWOSection; }
-
-  const DWARFSection &getStringOffsetDWOSection() override {
-    return StringOffsetDWOSection;
-  }
-
-  const DWARFSection &getRangeDWOSection() override { return RangeDWOSection; }
-
-  const DWARFSection &getAddrSection() override { return AddrSection; }
-
-  StringRef getCUIndexSection() override { return CUIndexSection; }
-  StringRef getGdbIndexSection() override { return GdbIndexSection; }
-  StringRef getTUIndexSection() override { return TUIndexSection; }
-};
-
 } // end namespace llvm
 
 #endif // LLVM_DEBUGINFO_DWARF_DWARFCONTEXT_H

include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h

 //===- DWARFDataExtractor.h -------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H
 #define LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H
 
 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
 #include "llvm/Support/DataExtractor.h"
 
 namespace llvm {
+class DWARFObj;
 
 /// A DataExtractor (typically for an in-memory copy of an object-file section)
 /// plus a relocation map for that section, if there is one.
 class DWARFDataExtractor : public DataExtractor {
-  const RelocAddrMap *RelocMap = nullptr;
+  const DWARFObj *Obj = nullptr;
+  const DWARFSection *Section = nullptr;
+
 public:
   /// Constructor for the normal case of extracting data from a DWARF section.
   /// The DWARFSection's lifetime must be at least as long as the extractor's.
-  DWARFDataExtractor(const DWARFSection &Section, bool IsLittleEndian,
-                     uint8_t AddressSize)
-    : DataExtractor(Section.Data, IsLittleEndian, AddressSize),
-      RelocMap(&Section.Relocs) {}
+  DWARFDataExtractor(const DWARFObj &Obj, const DWARFSection &Section,
+                     bool IsLittleEndian, uint8_t AddressSize)
+      : DataExtractor(Section.Data, IsLittleEndian, AddressSize), Obj(&Obj),
+        Section(&Section) {}
 
   /// Constructor for cases when there are no relocations.
   DWARFDataExtractor(StringRef Data, bool IsLittleEndian, uint8_t AddressSize)
     : DataExtractor(Data, IsLittleEndian, AddressSize) {}
 
   /// Extracts a value and applies a relocation to the result if
   /// one exists for the given offset.
   uint64_t getRelocatedValue(uint32_t Size, uint32_t *Off,

include/llvm/DebugInfo/DWARF/DWARFObj.h

+//===- DWARFObj.h ----------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===/
+
+#ifndef LLVM_DEBUGINFO_DWARF_DWARFOBJ_H
+#define LLVM_DEBUGINFO_DWARF_DWARFOBJ_H
+
+#include "llvm/DebugInfo/DWARF/DWARFSection.h"
+
+namespace llvm {
+// This is responsible for low level access to the object file. It
+// knows how to find the required sections and compute relocated
+// values.
+// The default implementations of the get<Section> methods return dummy values.
+// This is to allow clients that only need some of those to implement just the
+// ones they need. We can't use unreachable for as many cases because the parser
+// implementation is eager and will call some of these methods even if the
+// result is not used.
+class DWARFObj {
+  DWARFSection Dummy;
+
+public:
+  virtual ~DWARFObj() = default;
+  virtual StringRef getFileName() const { llvm_unreachable("unimplemented"); }
+  virtual bool isLittleEndian() const = 0;
+  virtual uint8_t getAddressSize() const { llvm_unreachable("unimplemented"); }
+  virtual const DWARFSection &getInfoSection() const { return Dummy; }
+  virtual void
+  forEachTypesSections(function_ref<void(const DWARFSection &)> F) const {}
+  virtual StringRef getAbbrevSection() const { return ""; }
+  virtual const DWARFSection &getLocSection() const { return Dummy; }
+  virtual StringRef getARangeSection() const { return ""; }
+  virtual StringRef getDebugFrameSection() const { return ""; }
+  virtual StringRef getEHFrameSection() const { return ""; }
+  virtual const DWARFSection &getLineSection() const { return Dummy; }
+  virtual StringRef getStringSection() const { return ""; }
+  virtual const DWARFSection &getRangeSection() const { return Dummy; }
+  virtual StringRef getMacinfoSection() const { return ""; }
+  virtual StringRef getPubNamesSection() const { return ""; }
+  virtual StringRef getPubTypesSection() const { return ""; }
+  virtual StringRef getGnuPubNamesSection() const { return ""; }
+  virtual StringRef getGnuPubTypesSection() const { return ""; }
+  virtual const DWARFSection &getStringOffsetSection() const { return Dummy; }
+  virtual const DWARFSection &getInfoDWOSection() const { return Dummy; }
+  virtual void
+  forEachTypesDWOSections(function_ref<void(const DWARFSection &)> F) const {}
+  virtual StringRef getAbbrevDWOSection() const { return ""; }
+  virtual const DWARFSection &getLineDWOSection() const { return Dummy; }
+  virtual const DWARFSection &getLocDWOSection() const { return Dummy; }
+  virtual StringRef getStringDWOSection() const { return ""; }
+  virtual const DWARFSection &getStringOffsetDWOSection() const {
+    return Dummy;
+  }
+  virtual const DWARFSection &getRangeDWOSection() const { return Dummy; }
+  virtual const DWARFSection &getAddrSection() const { return Dummy; }
+  virtual const DWARFSection &getAppleNamesSection() const { return Dummy; }
+  virtual const DWARFSection &getAppleTypesSection() const { return Dummy; }
+  virtual const DWARFSection &getAppleNamespacesSection() const {
+    return Dummy;
+  }
+  virtual const DWARFSection &getAppleObjCSection() const { return Dummy; }
+  virtual StringRef getCUIndexSection() const { return ""; }
+  virtual StringRef getGdbIndexSection() const { return ""; }
+  virtual StringRef getTUIndexSection() const { return ""; }
+  virtual Optional<RelocAddrEntry> find(const DWARFSection &Sec,
+                                        uint64_t Pos) const = 0;
+};
+
+} // namespace llvm
+#endif

include/llvm/DebugInfo/DWARF/DWARFSection.h

 #ifndef LLVM_DEBUGINFO_DWARF_DWARFSECTION_H
 #define LLVM_DEBUGINFO_DWARF_DWARFSECTION_H
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
 
 namespace llvm {
 
 struct DWARFSection {
   StringRef Data;
+};
+
+struct DWARFSectionMap final : public DWARFSection {
   RelocAddrMap Relocs;
 };
 
 } // end namespace llvm
 
 #endif // LLVM_DEBUGINFO_DWARF_DWARFSECTION_H

include/llvm/DebugInfo/DWARF/DWARFUnit.h

public:
   void setRangesSection(const DWARFSection *RS, uint32_t Base) {
     RangeSection = RS;
     RangeSectionBase = Base;
   }
 
   bool getAddrOffsetSectionItem(uint32_t Index, uint64_t &Result) const;
   bool getStringOffsetSectionItem(uint32_t Index, uint64_t &Result) const;
 
-  DWARFDataExtractor getDebugInfoExtractor() const {
-    return DWARFDataExtractor(InfoSection, isLittleEndian,
-                              getAddressByteSize());
-  }
+  DWARFDataExtractor getDebugInfoExtractor() const;
 
   DataExtractor getStringExtractor() const {
     return DataExtractor(StringSection, false, 0);
   }
 
-  const RelocAddrMap *getRelocMap() const { return &InfoSection.Relocs; }
-  const RelocAddrMap &getStringOffsetsRelocMap() const {
-    return StringOffsetSection.Relocs;
-  }
 
   bool extract(DataExtractor debug_info, uint32_t* offset_ptr);
 
   /// extractRangeList - extracts the range list referenced by this compile
   /// unit from .debug_ranges section. Returns true on success.
   /// Requires that compile unit is already extracted.
   bool extractRangeList(uint32_t RangeListOffset,
                         DWARFDebugRangeList &RangeList) const;

lib/DebugInfo/DWARF/DWARFContext.cpp

 
 #define DEBUG_TYPE "dwarf"
 
 using DWARFLineTable = DWARFDebugLine::LineTable;
 using FileLineInfoKind = DILineInfoSpecifier::FileLineInfoKind;
 using FunctionNameKind = DILineInfoSpecifier::FunctionNameKind;
 
 static void dumpAccelSection(raw_ostream &OS, StringRef Name,
-                             const DWARFSection& Section, StringRef StringSection,
-                             bool LittleEndian) {
-  DWARFDataExtractor AccelSection(Section, LittleEndian, 0);
+                             const DWARFObj &Obj, const DWARFSection &Section,
+                             StringRef StringSection, bool LittleEndian) {
+  DWARFDataExtractor AccelSection(Obj, Section, LittleEndian, 0);
   DataExtractor StrData(StringSection, LittleEndian, 0);
   OS << "\n." << Name << " contents:\n";
   DWARFAcceleratorTable Accel(AccelSection, StrData);
   if (!Accel.extract())
     return;
   Accel.dump(OS);
 }
 
 static void
 dumpDWARFv5StringOffsetsSection(raw_ostream &OS, StringRef SectionName,
+                                const DWARFObj &Obj,
                                 const DWARFSection &StringOffsetsSection,
                                 StringRef StringSection, bool LittleEndian) {
-  DWARFDataExtractor StrOffsetExt(StringOffsetsSection, LittleEndian, 0);
+  DWARFDataExtractor StrOffsetExt(Obj, StringOffsetsSection, LittleEndian, 0);
   uint32_t Offset = 0;
   uint64_t SectionSize = StringOffsetsSection.Data.size();
 
   while (Offset < SectionSize) {
     unsigned Version = 0;
     DwarfFormat Format = DWARF32;
     unsigned EntrySize = 4;
     // Perform validation and extract the segment size from the header.

 
 // Dump a DWARF string offsets section. This may be a DWARF v5 formatted
 // string offsets section, where each compile or type unit contributes a
 // number of entries (string offsets), with each contribution preceded by
 // a header containing size and version number. Alternatively, it may be a
 // monolithic series of string offsets, as generated by the pre-DWARF v5
 // implementation of split DWARF.
 static void dumpStringOffsetsSection(raw_ostream &OS, StringRef SectionName,
+                                     const DWARFObj &Obj,
                                      const DWARFSection &StringOffsetsSection,
                                      StringRef StringSection, bool LittleEndian,
                                      unsigned MaxVersion) {
   if (StringOffsetsSection.Data.empty())
     return;
   OS << "\n." << SectionName << " contents:\n";
   // If we have at least one (compile or type) unit with DWARF v5 or greater,
   // we assume that the section is formatted like a DWARF v5 string offsets
   // section.
   if (MaxVersion >= 5)
-    dumpDWARFv5StringOffsetsSection(OS, SectionName, StringOffsetsSection,
+    dumpDWARFv5StringOffsetsSection(OS, SectionName, Obj, StringOffsetsSection,
                                     StringSection, LittleEndian);
   else {
     DataExtractor strOffsetExt(StringOffsetsSection.Data, LittleEndian, 0);
     uint32_t offset = 0;
     uint64_t size = StringOffsetsSection.Data.size();
     // Ensure that size is a multiple of the size of an entry.
     if (size & ((uint64_t)(sizeof(uint32_t) - 1))) {
       OS << "error: size of ." << SectionName << " is not a multiple of "
void DWARFContext::dump(raw_ostream &OS, DIDumpOptions DumpOpts) {
   if (DumpType == DIDT_All || DumpType == DIDT_Macro) {
     OS << "\n.debug_macinfo contents:\n";
     getDebugMacro()->dump(OS);
   }
 
   uint32_t offset = 0;
   if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
     OS << "\n.debug_aranges contents:\n";
-    DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);
+    DataExtractor arangesData(DObj->getARangeSection(), isLittleEndian(), 0);
     DWARFDebugArangeSet set;
     while (set.extract(arangesData, &offset))
       set.dump(OS);
   }
 
   uint8_t savedAddressByteSize = 0;
   if (DumpType == DIDT_All || DumpType == DIDT_Line) {
     OS << "\n.debug_line contents:\n";
     for (const auto &CU : compile_units()) {
       savedAddressByteSize = CU->getAddressByteSize();
       auto CUDIE = CU->getUnitDIE();
       if (!CUDIE)
         continue;
       if (auto StmtOffset = toSectionOffset(CUDIE.find(DW_AT_stmt_list))) {
-        DWARFDataExtractor lineData(getLineSection(), isLittleEndian(),
-                                    savedAddressByteSize);
+        DWARFDataExtractor lineData(*DObj, DObj->getLineSection(),
+                                    isLittleEndian(), savedAddressByteSize);
         DWARFDebugLine::LineTable LineTable;
         uint32_t Offset = *StmtOffset;
         LineTable.parse(lineData, &Offset);
         LineTable.dump(OS);
       }
     }
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_CUIndex) {
     OS << "\n.debug_cu_index contents:\n";
     getCUIndex().dump(OS);
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_TUIndex) {
     OS << "\n.debug_tu_index contents:\n";
     getTUIndex().dump(OS);
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_LineDwo) {
     OS << "\n.debug_line.dwo contents:\n";
     unsigned stmtOffset = 0;
-    DWARFDataExtractor lineData(getLineDWOSection(), isLittleEndian(),
-                                savedAddressByteSize);
+    DWARFDataExtractor lineData(*DObj, DObj->getLineDWOSection(),
+                                isLittleEndian(), savedAddressByteSize);
     DWARFDebugLine::LineTable LineTable;
     while (LineTable.Prologue.parse(lineData, &stmtOffset)) {
       LineTable.dump(OS);
       LineTable.clear();
     }
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_Str) {
     OS << "\n.debug_str contents:\n";
-    DataExtractor strData(getStringSection(), isLittleEndian(), 0);
+    DataExtractor strData(DObj->getStringSection(), isLittleEndian(), 0);
     offset = 0;
     uint32_t strOffset = 0;
     while (const char *s = strData.getCStr(&offset)) {
       OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
       strOffset = offset;
     }
   }
 
   if ((DumpType == DIDT_All || DumpType == DIDT_StrDwo) &&
-      !getStringDWOSection().empty()) {
+      !DObj->getStringDWOSection().empty()) {
     OS << "\n.debug_str.dwo contents:\n";
-    DataExtractor strDWOData(getStringDWOSection(), isLittleEndian(), 0);
+    DataExtractor strDWOData(DObj->getStringDWOSection(), isLittleEndian(), 0);
     offset = 0;
     uint32_t strDWOOffset = 0;
     while (const char *s = strDWOData.getCStr(&offset)) {
       OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s);
       strDWOOffset = offset;
     }
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_Ranges) {
     OS << "\n.debug_ranges contents:\n";
     // In fact, different compile units may have different address byte
     // sizes, but for simplicity we just use the address byte size of the last
     // compile unit (there is no easy and fast way to associate address range
     // list and the compile unit it describes).
-    DWARFDataExtractor rangesData(getRangeSection(), isLittleEndian(),
-                                  savedAddressByteSize);
+    DWARFDataExtractor rangesData(*DObj, DObj->getRangeSection(),
+                                  isLittleEndian(), savedAddressByteSize);
     offset = 0;
     DWARFDebugRangeList rangeList;
     while (rangeList.extract(rangesData, &offset))
       rangeList.dump(OS);
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
-    DWARFDebugPubTable(getPubNamesSection(), isLittleEndian(), false)
+    DWARFDebugPubTable(DObj->getPubNamesSection(), isLittleEndian(), false)
         .dump("debug_pubnames", OS);
 
   if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
-    DWARFDebugPubTable(getPubTypesSection(), isLittleEndian(), false)
+    DWARFDebugPubTable(DObj->getPubTypesSection(), isLittleEndian(), false)
         .dump("debug_pubtypes", OS);
 
   if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
-    DWARFDebugPubTable(getGnuPubNamesSection(), isLittleEndian(),
+    DWARFDebugPubTable(DObj->getGnuPubNamesSection(), isLittleEndian(),
                        true /* GnuStyle */)
         .dump("debug_gnu_pubnames", OS);
 
   if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
-    DWARFDebugPubTable(getGnuPubTypesSection(), isLittleEndian(),
+    DWARFDebugPubTable(DObj->getGnuPubTypesSection(), isLittleEndian(),
                        true /* GnuStyle */)
         .dump("debug_gnu_pubtypes", OS);
 
   if (DumpType == DIDT_All || DumpType == DIDT_StrOffsets)
-    dumpStringOffsetsSection(OS, "debug_str_offsets", getStringOffsetSection(),
-                             getStringSection(), isLittleEndian(),
-                             getMaxVersion());
+    dumpStringOffsetsSection(
+        OS, "debug_str_offsets", *DObj, DObj->getStringOffsetSection(),
+        DObj->getStringSection(), isLittleEndian(), getMaxVersion());
 
   if (DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) {
-    dumpStringOffsetsSection(OS, "debug_str_offsets.dwo",
-                             getStringOffsetDWOSection(), getStringDWOSection(),
-                             isLittleEndian(), getMaxVersion());
+    dumpStringOffsetsSection(
+        OS, "debug_str_offsets.dwo", *DObj, DObj->getStringOffsetDWOSection(),
+        DObj->getStringDWOSection(), isLittleEndian(), getMaxVersion());
   }
 
   if ((DumpType == DIDT_All || DumpType == DIDT_GdbIndex) &&
-      !getGdbIndexSection().empty()) {
+      !DObj->getGdbIndexSection().empty()) {
     OS << "\n.gnu_index contents:\n";
     getGdbIndex().dump(OS);
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_AppleNames)
-    dumpAccelSection(OS, "apple_names", getAppleNamesSection(),
-                     getStringSection(), isLittleEndian());
+    dumpAccelSection(OS, "apple_names", *DObj, DObj->getAppleNamesSection(),
+                     DObj->getStringSection(), isLittleEndian());
 
   if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes)
-    dumpAccelSection(OS, "apple_types", getAppleTypesSection(),
-                     getStringSection(), isLittleEndian());
+    dumpAccelSection(OS, "apple_types", *DObj, DObj->getAppleTypesSection(),
+                     DObj->getStringSection(), isLittleEndian());
 
   if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces)
-    dumpAccelSection(OS, "apple_namespaces", getAppleNamespacesSection(),
-                     getStringSection(), isLittleEndian());
+    dumpAccelSection(OS, "apple_namespaces", *DObj,
+                     DObj->getAppleNamespacesSection(),
+                     DObj->getStringSection(), isLittleEndian());
 
   if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC)
-    dumpAccelSection(OS, "apple_objc", getAppleObjCSection(),
-                     getStringSection(), isLittleEndian());
+    dumpAccelSection(OS, "apple_objc", *DObj, DObj->getAppleObjCSection(),
+                     DObj->getStringSection(), isLittleEndian());
 }
 
 DWARFCompileUnit *DWARFContext::getDWOCompileUnitForHash(uint64_t Hash) {
   // FIXME: Improve this for the case where this DWO file is really a DWP file
   // with an index - use the index for lookup instead of a linear search.
   for (const auto &DWOCU : dwo_compile_units())
     if (DWOCU->getDWOId() == Hash)
       return DWOCU.get();
bool DWARFContext::verify(raw_ostream &OS, DIDumpType DumpType) {
   }
   return Success;
 }
 
 const DWARFUnitIndex &DWARFContext::getCUIndex() {
   if (CUIndex)
     return *CUIndex;
 
-  DataExtractor CUIndexData(getCUIndexSection(), isLittleEndian(), 0);
+  DataExtractor CUIndexData(DObj->getCUIndexSection(), isLittleEndian(), 0);
 
   CUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_INFO);
   CUIndex->parse(CUIndexData);
   return *CUIndex;
 }
 
 const DWARFUnitIndex &DWARFContext::getTUIndex() {
   if (TUIndex)
     return *TUIndex;
 
-  DataExtractor TUIndexData(getTUIndexSection(), isLittleEndian(), 0);
+  DataExtractor TUIndexData(DObj->getTUIndexSection(), isLittleEndian(), 0);
 
   TUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_TYPES);
   TUIndex->parse(TUIndexData);
   return *TUIndex;
 }
 
 DWARFGdbIndex &DWARFContext::getGdbIndex() {
   if (GdbIndex)
     return *GdbIndex;
 
-  DataExtractor GdbIndexData(getGdbIndexSection(), true /*LE*/, 0);
+  DataExtractor GdbIndexData(DObj->getGdbIndexSection(), true /*LE*/, 0);
   GdbIndex = llvm::make_unique<DWARFGdbIndex>();
   GdbIndex->parse(GdbIndexData);
   return *GdbIndex;
 }
 
 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
   if (Abbrev)
     return Abbrev.get();
 
-  DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
+  DataExtractor abbrData(DObj->getAbbrevSection(), isLittleEndian(), 0);
 
   Abbrev.reset(new DWARFDebugAbbrev());
   Abbrev->extract(abbrData);
   return Abbrev.get();
 }
 
 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
   if (AbbrevDWO)
     return AbbrevDWO.get();
 
-  DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
+  DataExtractor abbrData(DObj->getAbbrevDWOSection(), isLittleEndian(), 0);
   AbbrevDWO.reset(new DWARFDebugAbbrev());
   AbbrevDWO->extract(abbrData);
   return AbbrevDWO.get();
 }
 
 const DWARFDebugLoc *DWARFContext::getDebugLoc() {
   if (Loc)
     return Loc.get();
 
   Loc.reset(new DWARFDebugLoc);
   // assume all compile units have the same address byte size
   if (getNumCompileUnits()) {
-    DWARFDataExtractor LocData(getLocSection(), isLittleEndian(),
+    DWARFDataExtractor LocData(*DObj, DObj->getLocSection(), isLittleEndian(),
                                getCompileUnitAtIndex(0)->getAddressByteSize());
     Loc->parse(LocData);
   }
   return Loc.get();
 }
 
 const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
   if (LocDWO)
     return LocDWO.get();
 
-  DataExtractor LocData(getLocDWOSection().Data, isLittleEndian(), 0);
+  DataExtractor LocData(DObj->getLocDWOSection().Data, isLittleEndian(), 0);
   LocDWO.reset(new DWARFDebugLocDWO());
   LocDWO->parse(LocData);
   return LocDWO.get();
 }
 
 const DWARFDebugAranges *DWARFContext::getDebugAranges() {
   if (Aranges)
     return Aranges.get();
const DWARFDebugFrame *DWARFContext::getDebugFrame() {
   // size within debug frame sections. While DWARF is supposed to be independent
   // of its container, FDEs have fields with size being "target address size",
   // which isn't specified in DWARF in general. It's only specified for CUs, but
   // .eh_frame can appear without a .debug_info section. Follow the example of
   // other tools (libdwarf) and extract this from the container (ObjectFile
   // provides this information). This problem is fixed in DWARFv4
   // See this dwarf-discuss discussion for more details:
   // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
-  DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(),
-                               getAddressSize());
+  DataExtractor debugFrameData(DObj->getDebugFrameSection(), isLittleEndian(),
+                               DObj->getAddressSize());
   DebugFrame.reset(new DWARFDebugFrame(false /* IsEH */));
   DebugFrame->parse(debugFrameData);
   return DebugFrame.get();
 }
 
 const DWARFDebugFrame *DWARFContext::getEHFrame() {
   if (EHFrame)
     return EHFrame.get();
 
-  DataExtractor debugFrameData(getEHFrameSection(), isLittleEndian(),
-                               getAddressSize());
+  DataExtractor debugFrameData(DObj->getEHFrameSection(), isLittleEndian(),
+                               DObj->getAddressSize());
   DebugFrame.reset(new DWARFDebugFrame(true /* IsEH */));
   DebugFrame->parse(debugFrameData);
   return DebugFrame.get();
 }
 
 const DWARFDebugMacro *DWARFContext::getDebugMacro() {
   if (Macro)
     return Macro.get();
 
-  DataExtractor MacinfoData(getMacinfoSection(), isLittleEndian(), 0);
+  DataExtractor MacinfoData(DObj->getMacinfoSection(), isLittleEndian(), 0);
   Macro.reset(new DWARFDebugMacro());
   Macro->parse(MacinfoData);
   return Macro.get();
 }
 
 const DWARFLineTable *
 DWARFContext::getLineTableForUnit(DWARFUnit *U) {
   if (!Line)
DWARFContext::getLineTableForUnit(DWARFUnit *U) {
   if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
     return lt;
 
   // Make sure the offset is good before we try to parse.
   if (stmtOffset >= U->getLineSection().Data.size())
     return nullptr;  
 
   // We have to parse it first.
-  DWARFDataExtractor lineData(U->getLineSection(), isLittleEndian(),
+  DWARFDataExtractor lineData(*DObj, U->getLineSection(), isLittleEndian(),
                               U->getAddressByteSize());
   return Line->getOrParseLineTable(lineData, stmtOffset);
 }
 
 void DWARFContext::parseCompileUnits() {
-  CUs.parse(*this, getInfoSection());
+  CUs.parse(*this, DObj->getInfoSection());
 }
 
 void DWARFContext::parseTypeUnits() {
   if (!TUs.empty())
     return;
-  forEachTypesSections([&](const DWARFSection &S) {
+  DObj->forEachTypesSections([&](const DWARFSection &S) {
     TUs.emplace_back();
     TUs.back().parse(*this, S);
   });
 }
 
 void DWARFContext::parseDWOCompileUnits() {
-  DWOCUs.parseDWO(*this, getInfoDWOSection());
+  DWOCUs.parseDWO(*this, DObj->getInfoDWOSection());
 }
 
 void DWARFContext::parseDWOTypeUnits() {
   if (!DWOTUs.empty())
     return;
-  forEachTypesDWOSections([&](const DWARFSection &S) {
+  DObj->forEachTypesDWOSections([&](const DWARFSection &S) {
     DWOTUs.emplace_back();
     DWOTUs.back().parseDWO(*this, S);
   });
 }
 
 DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
   parseCompileUnits();
   return CUs.getUnitForOffset(Offset);
if (Spec.FLIKind != FileLineInfoKind::None) {
                                    CallDiscriminator);
       }
     }
     InliningInfo.addFrame(Frame);
   }
   return InliningInfo;
 }
 
+/// DWARFContextInMemory is the simplest possible implementation of a
+/// DWARFContext. It assumes all content is available in memory and stores
+/// pointers to it.
+class DWARFContextInMemory : public DWARFContext {
+public:
+  DWARFContextInMemory(
+      const object::ObjectFile &Obj, const LoadedObjectInfo *L = nullptr,
+      function_ref<ErrorPolicy(Error)> HandleError = defaultErrorHandler);
+
+  DWARFContextInMemory(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
+                       uint8_t AddrSize,
+                       bool isLittleEndian = sys::IsLittleEndianHost);
+};
+
 std::shared_ptr<DWARFContext>
 DWARFContext::getDWOContext(StringRef AbsolutePath) {
   if (auto S = DWP.lock()) {
     DWARFContext *Ctxt = S->Context.get();
     return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
   }
 
   std::weak_ptr<DWOFile> *Entry = &DWOFiles[AbsolutePath];
 
   if (auto S = Entry->lock()) {
     DWARFContext *Ctxt = S->Context.get();
     return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
   }
 
   SmallString<128> DWPName;
   Expected<OwningBinary<ObjectFile>> Obj = [&] {
     if (!CheckedForDWP) {
-      (getFileName() + ".dwp").toVector(DWPName);
+      (DObj->getFileName() + ".dwp").toVector(DWPName);
       auto Obj = object::ObjectFile::createObjectFile(DWPName);
       if (Obj) {
         Entry = &DWP;
         return Obj;
       } else {
         CheckedForDWP = true;
         // TODO: Should this error be handled (maybe in a high verbosity mode)
         // before falling back to .dwo files?
         consumeError(Obj.takeError());
       }
     }
 
     return object::ObjectFile::createObjectFile(AbsolutePath);
   }();
 
   if (!Obj) {
     // TODO: Actually report errors helpfully.
     consumeError(Obj.takeError());
     return nullptr;
   }
 
   auto S = std::make_shared<DWOFile>();
   S->File = std::move(Obj.get());
-  S->Context = llvm::make_unique<DWARFContextInMemory>(*S->File.getBinary());
+  S->Context = DWARFContext::create(*S->File.getBinary());
   *Entry = S;
   auto *Ctxt = S->Context.get();
   return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
 }
 
 static Error createError(const Twine &Reason, llvm::Error E) {
   return make_error<StringError>(Reason + toString(std::move(E)),
                                  inconvertibleErrorCode());
static bool isRelocScattered(const object::ObjectFile &Obj,
   if (!MachObj)
     return false;
   // MachO also has relocations that point to sections and
   // scattered relocations.
   auto RelocInfo = MachObj->getRelocation(Reloc.getRawDataRefImpl());
   return MachObj->isRelocationScattered(RelocInfo);
 }
 
-Error DWARFContextInMemory::maybeDecompress(const SectionRef &Sec,
-                                            StringRef Name, StringRef &Data) {
+ErrorPolicy DWARFContext::defaultErrorHandler(Error E) {
+  errs() << "error: " + toString(std::move(E)) << '\n';
+  return ErrorPolicy::Continue;
+}
+
+class DWARFObjInMemory final : public DWARFObj {
+  bool IsLittleEndian;
+  uint8_t AddressSize;
+  StringRef FileName;
+
+  using TypeSectionMap = MapVector<object::SectionRef, DWARFSectionMap,
+                                   std::map<object::SectionRef, unsigned>>;
+
+  TypeSectionMap TypesSections;
+  TypeSectionMap TypesDWOSections;
+
+  DWARFSectionMap InfoSection;
+  DWARFSectionMap LocSection;
+  DWARFSectionMap LineSection;
+  DWARFSectionMap RangeSection;
+  DWARFSectionMap StringOffsetSection;
+  DWARFSectionMap InfoDWOSection;
+  DWARFSectionMap LineDWOSection;
+  DWARFSectionMap LocDWOSection;
+  DWARFSectionMap StringOffsetDWOSection;
+  DWARFSectionMap RangeDWOSection;
+  DWARFSectionMap AddrSection;
+  DWARFSectionMap AppleNamesSection;
+  DWARFSectionMap AppleTypesSection;
+  DWARFSectionMap AppleNamespacesSection;
+  DWARFSectionMap AppleObjCSection;
+
+  DWARFSectionMap *mapNameToDWARFSection(StringRef Name) {
+    return StringSwitch<DWARFSectionMap *>(Name)
+        .Case("debug_info", &InfoSection)
+        .Case("debug_loc", &LocSection)
+        .Case("debug_line", &LineSection)
+        .Case("debug_str_offsets", &StringOffsetSection)
+        .Case("debug_ranges", &RangeSection)
+        .Case("debug_info.dwo", &InfoDWOSection)
+        .Case("debug_loc.dwo", &LocDWOSection)
+        .Case("debug_line.dwo", &LineDWOSection)
+        .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
+        .Case("debug_addr", &AddrSection)
+        .Case("apple_names", &AppleNamesSection)
+        .Case("apple_types", &AppleTypesSection)
+        .Case("apple_namespaces", &AppleNamespacesSection)
+        .Case("apple_namespac", &AppleNamespacesSection)
+        .Case("apple_objc", &AppleObjCSection)
+        .Default(nullptr);
+  }
+
+  StringRef AbbrevSection;
+  StringRef ARangeSection;
+  StringRef DebugFrameSection;
+  StringRef EHFrameSection;
+  StringRef StringSection;
+  StringRef MacinfoSection;
+  StringRef PubNamesSection;
+  StringRef PubTypesSection;
+  StringRef GnuPubNamesSection;
+  StringRef AbbrevDWOSection;
+  StringRef StringDWOSection;
+  StringRef GnuPubTypesSection;
+  StringRef CUIndexSection;
+  StringRef GdbIndexSection;
+  StringRef TUIndexSection;
+
+  SmallVector<SmallString<32>, 4> UncompressedSections;
+
+  StringRef *mapSectionToMember(StringRef Name) {
+    if (DWARFSection *Sec = mapNameToDWARFSection(Name))
+      return &Sec->Data;
+    return StringSwitch<StringRef *>(Name)
+        .Case("debug_abbrev", &AbbrevSection)
+        .Case("debug_aranges", &ARangeSection)
+        .Case("debug_frame", &DebugFrameSection)
+        .Case("eh_frame", &EHFrameSection)
+        .Case("debug_str", &StringSection)
+        .Case("debug_macinfo", &MacinfoSection)
+        .Case("debug_pubnames", &PubNamesSection)
+        .Case("debug_pubtypes", &PubTypesSection)
+        .Case("debug_gnu_pubnames", &GnuPubNamesSection)
+        .Case("debug_gnu_pubtypes", &GnuPubTypesSection)
+        .Case("debug_abbrev.dwo", &AbbrevDWOSection)
+        .Case("debug_str.dwo", &StringDWOSection)
+        .Case("debug_cu_index", &CUIndexSection)
+        .Case("debug_tu_index", &TUIndexSection)
+        .Case("gdb_index", &GdbIndexSection)
+        // Any more debug info sections go here.
+        .Default(nullptr);
+  }
+
+  /// If Sec is compressed section, decompresses and updates its contents
+  /// provided by Data. Otherwise leaves it unchanged.
+  Error maybeDecompress(const object::SectionRef &Sec, StringRef Name,
+                        StringRef &Data) {
     if (!Decompressor::isCompressed(Sec))
       return Error::success();
 
     Expected<Decompressor> Decompressor =
         Decompressor::create(Name, Data, IsLittleEndian, AddressSize == 8);
     if (!Decompressor)
       return Decompressor.takeError();
 
     SmallString<32> Out;
     if (auto Err = Decompressor->resizeAndDecompress(Out))
       return Err;
 
     UncompressedSections.emplace_back(std::move(Out));
     Data = UncompressedSections.back();
 
     return Error::success();
   }
 
-ErrorPolicy DWARFContextInMemory::defaultErrorHandler(Error E) {
-  errs() << "error: " + toString(std::move(E)) << '\n';
-  return ErrorPolicy::Continue;
+public:
+  DWARFObjInMemory(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
+                   uint8_t AddrSize, bool IsLittleEndian)
+      : IsLittleEndian(IsLittleEndian) {
+    for (const auto &SecIt : Sections) {
+      if (StringRef *SectionData = mapSectionToMember(SecIt.first()))
+        *SectionData = SecIt.second->getBuffer();
     }
-
-DWARFContextInMemory::DWARFContextInMemory(
-    const object::ObjectFile &Obj, const LoadedObjectInfo *L,
+  }
+  DWARFObjInMemory(const object::ObjectFile &Obj, const LoadedObjectInfo *L,
                    function_ref<ErrorPolicy(Error)> HandleError)
-    : FileName(Obj.getFileName()), IsLittleEndian(Obj.isLittleEndian()),
-      AddressSize(Obj.getBytesInAddress()) {
+      : IsLittleEndian(Obj.isLittleEndian()),
+        AddressSize(Obj.getBytesInAddress()), FileName(Obj.getFileName()) {
+
     for (const SectionRef &Section : Obj.sections()) {
       StringRef Name;
       Section.getName(Name);
       // Skip BSS and Virtual sections, they aren't interesting.
       if (Section.isBSS() || Section.isVirtual())
         continue;
 
       StringRef Data;
       section_iterator RelocatedSection = Section.getRelocatedSection();
       // Try to obtain an already relocated version of this section.
       // Else use the unrelocated section from the object file. We'll have to
       // apply relocations ourselves later.
       if (!L || !L->getLoadedSectionContents(*RelocatedSection, Data))
         Section.getContents(Data);
 
       if (auto Err = maybeDecompress(Section, Name, Data)) {
-      ErrorPolicy EP = HandleError(
-          createError("failed to decompress '" + Name + "', ", std::move(Err)));
+        ErrorPolicy EP = HandleError(createError(
+            "failed to decompress '" + Name + "', ", std::move(Err)));
         if (EP == ErrorPolicy::Halt)
           return;
         continue;
       }
 
       // Compressed sections names in GNU style starts from ".z",
       // at this point section is decompressed and we drop compression prefix.
       Name = Name.substr(
           Name.find_first_not_of("._z")); // Skip ".", "z" and "_" prefixes.
 
       // Map platform specific debug section names to DWARF standard section
       // names.
       Name = Obj.mapDebugSectionName(Name);
 
       if (StringRef *SectionData = mapSectionToMember(Name)) {
         *SectionData = Data;
         if (Name == "debug_ranges") {
           // FIXME: Use the other dwo range section when we emit it.
           RangeDWOSection.Data = Data;
         }
       } else if (Name == "debug_types") {
         // Find debug_types data by section rather than name as there are
         // multiple, comdat grouped, debug_types sections.
         TypesSections[Section].Data = Data;
       } else if (Name == "debug_types.dwo") {
         TypesDWOSections[Section].Data = Data;
       }
 
       if (RelocatedSection == Obj.section_end())
         continue;
 
       StringRef RelSecName;
       StringRef RelSecData;
       RelocatedSection->getName(RelSecName);
 
       // If the section we're relocating was relocated already by the JIT,
       // then we used the relocated version above, so we do not need to process
       // relocations for it now.
       if (L && L->getLoadedSectionContents(*RelocatedSection, RelSecData))
         continue;
 
       // In Mach-o files, the relocations do not need to be applied if
       // there is no load offset to apply. The value read at the
       // relocation point already factors in the section address
       // (actually applying the relocations will produce wrong results
       // as the section address will be added twice).
       if (!L && isa<MachOObjectFile>(&Obj))
         continue;
 
       RelSecName = RelSecName.substr(
           RelSecName.find_first_not_of("._z")); // Skip . and _ prefixes.
 
       // TODO: Add support for relocations in other sections as needed.
       // Record relocations for the debug_info and debug_line sections.
-    DWARFSection *Sec = mapNameToDWARFSection(RelSecName);
+      DWARFSectionMap *Sec = mapNameToDWARFSection(RelSecName);
       RelocAddrMap *Map = Sec ? &Sec->Relocs : nullptr;
       if (!Map) {
         // Find debug_types relocs by section rather than name as there are
         // multiple, comdat grouped, debug_types sections.
         if (RelSecName == "debug_types")
-        Map = &TypesSections[*RelocatedSection].Relocs;
+          Map =
+              &static_cast<DWARFSectionMap &>(TypesSections[*RelocatedSection])
+                   .Relocs;
         else if (RelSecName == "debug_types.dwo")
-        Map = &TypesDWOSections[*RelocatedSection].Relocs;
+          Map = &static_cast<DWARFSectionMap &>(
+                     TypesDWOSections[*RelocatedSection])
+                     .Relocs;
         else
           continue;
       }
 
       if (Section.relocation_begin() == Section.relocation_end())
         continue;
 
       // Symbol to [address, section index] cache mapping.
       std::map<SymbolRef, SymInfo> AddrCache;
       for (const RelocationRef &Reloc : Section.relocations()) {
         // FIXME: it's not clear how to correctly handle scattered
         // relocations.
         if (isRelocScattered(Obj, Reloc))
           continue;
 
-      Expected<SymInfo> SymInfoOrErr = getSymbolInfo(Obj, Reloc, L, AddrCache);
+        Expected<SymInfo> SymInfoOrErr =
+            getSymbolInfo(Obj, Reloc, L, AddrCache);
         if (!SymInfoOrErr) {
           if (HandleError(SymInfoOrErr.takeError()) == ErrorPolicy::Halt)
             return;
           continue;
         }
 
         object::RelocVisitor V(Obj);
         uint64_t Val = V.visit(Reloc.getType(), Reloc, SymInfoOrErr->Address);
         if (V.error()) {
           SmallString<32> Type;
           Reloc.getTypeName(Type);
           ErrorPolicy EP = HandleError(
               createError("failed to compute relocation: " + Type + ", ",
                           errorCodeToError(object_error::parse_failed)));
           if (EP == ErrorPolicy::Halt)
             return;
           continue;
         }
         RelocAddrEntry Rel = {SymInfoOrErr->SectionIndex, Val};
         Map->insert({Reloc.getOffset(), Rel});
       }
     }
   }
 
-DWARFContextInMemory::DWARFContextInMemory(
-    const StringMap<std::unique_ptr<MemoryBuffer>> &Sections, uint8_t AddrSize,
-    bool isLittleEndian)
-    : IsLittleEndian(isLittleEndian), AddressSize(AddrSize) {
-  for (const auto &SecIt : Sections) {
-    if (StringRef *SectionData = mapSectionToMember(SecIt.first()))
-      *SectionData = SecIt.second->getBuffer();
-  }
+  Optional<RelocAddrEntry> find(const DWARFSection &S,
+                                uint64_t Pos) const override {
+    auto &Sec = static_cast<const DWARFSectionMap &>(S);
+    RelocAddrMap::const_iterator AI = Sec.Relocs.find(Pos);
+    if (AI == Sec.Relocs.end())
+      return None;
+    return AI->second;
+  }
+
+  bool isLittleEndian() const override { return IsLittleEndian; }
+  StringRef getAbbrevDWOSection() const override { return AbbrevDWOSection; }
+  const DWARFSection &getLineDWOSection() const override {
+    return LineDWOSection;
+  }
+  const DWARFSection &getLocDWOSection() const override {
+    return LocDWOSection;
+  }
+  StringRef getStringDWOSection() const override { return StringDWOSection; }
+  const DWARFSection &getStringOffsetDWOSection() const override {
+    return StringOffsetDWOSection;
+  }
+  const DWARFSection &getRangeDWOSection() const override {
+    return RangeDWOSection;
+  }
+  const DWARFSection &getAddrSection() const override { return AddrSection; }
+  StringRef getCUIndexSection() const override { return CUIndexSection; }
+  StringRef getGdbIndexSection() const override { return GdbIndexSection; }
+  StringRef getTUIndexSection() const override { return TUIndexSection; }
+
+  // DWARF v5
+  const DWARFSection &getStringOffsetSection() const override {
+    return StringOffsetSection;
+  }
+
+  // Sections for DWARF5 split dwarf proposal.
+  const DWARFSection &getInfoDWOSection() const override {
+    return InfoDWOSection;
+  }
+  void forEachTypesDWOSections(
+      function_ref<void(const DWARFSection &)> F) const override {
+    for (auto &P : TypesDWOSections)
+      F(P.second);
+  }
+
+  StringRef getAbbrevSection() const override { return AbbrevSection; }
+  const DWARFSection &getLocSection() const override { return LocSection; }
+  StringRef getARangeSection() const override { return ARangeSection; }
+  StringRef getDebugFrameSection() const override { return DebugFrameSection; }
+  StringRef getEHFrameSection() const override { return EHFrameSection; }
+  const DWARFSection &getLineSection() const override { return LineSection; }
+  StringRef getStringSection() const override { return StringSection; }
+  const DWARFSection &getRangeSection() const override { return RangeSection; }
+  StringRef getMacinfoSection() const override { return MacinfoSection; }
+  StringRef getPubNamesSection() const override { return PubNamesSection; }
+  StringRef getPubTypesSection() const override { return PubTypesSection; }
+  StringRef getGnuPubNamesSection() const override {
+    return GnuPubNamesSection;
+  }
+  StringRef getGnuPubTypesSection() const override {
+    return GnuPubTypesSection;
+  }
+  const DWARFSection &getAppleNamesSection() const override {
+    return AppleNamesSection;
+  }
+  const DWARFSection &getAppleTypesSection() const override {
+    return AppleTypesSection;
+  }
+  const DWARFSection &getAppleNamespacesSection() const override {
+    return AppleNamespacesSection;
+  }
+  const DWARFSection &getAppleObjCSection() const override {
+    return AppleObjCSection;
+  }
+
+  StringRef getFileName() const override { return FileName; }
+  uint8_t getAddressSize() const override { return AddressSize; }
+  const DWARFSection &getInfoSection() const override { return InfoSection; }
+  void forEachTypesSections(
+      function_ref<void(const DWARFSection &)> F) const override {
+    for (auto &P : TypesSections)
+      F(P.second);
   }
+};
 
-DWARFSection *DWARFContextInMemory::mapNameToDWARFSection(StringRef Name) {
-  return StringSwitch<DWARFSection *>(Name)
-      .Case("debug_info", &InfoSection)
-      .Case("debug_loc", &LocSection)
-      .Case("debug_line", &LineSection)
-      .Case("debug_str_offsets", &StringOffsetSection)
-      .Case("debug_ranges", &RangeSection)
-      .Case("debug_info.dwo", &InfoDWOSection)
-      .Case("debug_loc.dwo", &LocDWOSection)
-      .Case("debug_line.dwo", &LineDWOSection)
-      .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
-      .Case("debug_addr", &AddrSection)
-      .Case("apple_names", &AppleNamesSection)
-      .Case("apple_types", &AppleTypesSection)
-      .Case("apple_namespaces", &AppleNamespacesSection)
-      .Case("apple_namespac", &AppleNamespacesSection)
-      .Case("apple_objc", &AppleObjCSection)
-      .Default(nullptr);
+std::unique_ptr<DWARFContext>
+DWARFContext::create(const object::ObjectFile &Obj, const LoadedObjectInfo *L,
+                     function_ref<ErrorPolicy(Error)> HandleError) {
+  auto DObj = make_unique<DWARFObjInMemory>(Obj, L, HandleError);
+  return make_unique<DWARFContext>(std::move(DObj));
 }
 
-StringRef *DWARFContextInMemory::mapSectionToMember(StringRef Name) {
-  if (DWARFSection *Sec = mapNameToDWARFSection(Name))
-    return &Sec->Data;
-  return StringSwitch<StringRef *>(Name)
-      .Case("debug_abbrev", &AbbrevSection)
-      .Case("debug_aranges", &ARangeSection)
-      .Case("debug_frame", &DebugFrameSection)
-      .Case("eh_frame", &EHFrameSection)
-      .Case("debug_str", &StringSection)
-      .Case("debug_macinfo", &MacinfoSection)
-      .Case("debug_pubnames", &PubNamesSection)
-      .Case("debug_pubtypes", &PubTypesSection)
-      .Case("debug_gnu_pubnames", &GnuPubNamesSection)
-      .Case("debug_gnu_pubtypes", &GnuPubTypesSection)
-      .Case("debug_abbrev.dwo", &AbbrevDWOSection)
-      .Case("debug_str.dwo", &StringDWOSection)
-      .Case("debug_cu_index", &CUIndexSection)
-      .Case("debug_tu_index", &TUIndexSection)
-      .Case("gdb_index", &GdbIndexSection)
-      // Any more debug info sections go here.
-      .Default(nullptr);
+std::unique_ptr<DWARFContext>
+DWARFContext::create(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
+                     uint8_t AddrSize, bool isLittleEndian) {
+  auto DObj = make_unique<DWARFObjInMemory>(Sections, AddrSize, isLittleEndian);
+  return make_unique<DWARFContext>(std::move(DObj));
 }
-
-void DWARFContextInMemory::anchor() {}

lib/DebugInfo/DWARF/DWARFDataExtractor.cpp

 //===- DWARFDataExtractor.cpp ---------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 
 using namespace llvm;
 
 uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint32_t *Off,
                                                uint64_t *SecNdx) const {
-  if (!RelocMap)
+  if (!Section)
     return getUnsigned(Off, Size);
-  RelocAddrMap::const_iterator AI = RelocMap->find(*Off);
-  if (AI == RelocMap->end())
+  Optional<RelocAddrEntry> Rel = Obj->find(*Section, *Off);
+  if (!Rel)
     return getUnsigned(Off, Size);
   if (SecNdx)
-    *SecNdx = AI->second.SectionIndex;
-  return getUnsigned(Off, Size) + AI->second.Value;
+    *SecNdx = Rel->SectionIndex;
+  return getUnsigned(Off, Size) + Rel->Value;
 }

lib/DebugInfo/DWARF/DWARFDebugAranges.cpp

 }
 
 void DWARFDebugAranges::generate(DWARFContext *CTX) {
   clear();
   if (!CTX)
     return;
 
   // Extract aranges from .debug_aranges section.
-  DataExtractor ArangesData(CTX->getARangeSection(), CTX->isLittleEndian(), 0);
+  DataExtractor ArangesData(CTX->getDWARFObj().getARangeSection(),
+                            CTX->isLittleEndian(), 0);
   extract(ArangesData);
 
   // Generate aranges from DIEs: even if .debug_aranges section is present,
   // it may describe only a small subset of compilation units, so we need to
   // manually build aranges for the rest of them.
   for (const auto &CU : CTX->compile_units()) {
     uint32_t CUOffset = CU->getOffset();
     if (ParsedCUOffsets.insert(CUOffset).second) {

lib/DebugInfo/DWARF/DWARFUnit.cpp

 #include <cstdio>
 #include <utility>
 #include <vector>
 
 using namespace llvm;
 using namespace dwarf;
 
 void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
-  parseImpl(C, Section, C.getDebugAbbrev(), &C.getRangeSection(),
-            C.getStringSection(), C.getStringOffsetSection(),
-            &C.getAddrSection(), C.getLineSection(), C.isLittleEndian(), false);
+  const DWARFObj &D = C.getDWARFObj();
+  parseImpl(C, Section, C.getDebugAbbrev(), &D.getRangeSection(),
+            D.getStringSection(), D.getStringOffsetSection(),
+            &D.getAddrSection(), D.getLineSection(), D.isLittleEndian(), false);
 }
 
 void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
                                     const DWARFSection &DWOSection,
                                     DWARFUnitIndex *Index) {
-  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), &C.getRangeDWOSection(),
-            C.getStringDWOSection(), C.getStringOffsetDWOSection(),
-            &C.getAddrSection(), C.getLineDWOSection(), C.isLittleEndian(),
+  const DWARFObj &D = C.getDWARFObj();
+  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), &D.getRangeDWOSection(),
+            D.getStringDWOSection(), D.getStringOffsetDWOSection(),
+            &D.getAddrSection(), D.getLineDWOSection(), C.isLittleEndian(),
             true);
 }
 
 DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
                      const DWARFDebugAbbrev *DA, const DWARFSection *RS,
                      StringRef SS, const DWARFSection &SOS,
                      const DWARFSection *AOS, const DWARFSection &LS, bool LE,
                      bool IsDWO, const DWARFUnitSectionBase &UnitSection,
                      const DWARFUnitIndex::Entry *IndexEntry)
     : Context(DC), InfoSection(Section), Abbrev(DA), RangeSection(RS),
       LineSection(LS), StringSection(SS), StringOffsetSection(SOS),
       AddrOffsetSection(AOS), isLittleEndian(LE), isDWO(IsDWO),
       UnitSection(UnitSection), IndexEntry(IndexEntry) {
   clear();
 }
 
 DWARFUnit::~DWARFUnit() = default;
 
+DWARFDataExtractor DWARFUnit::getDebugInfoExtractor() const {
+  return DWARFDataExtractor(Context.getDWARFObj(), InfoSection, isLittleEndian,
+                            getAddressByteSize());
+}
+
 bool DWARFUnit::getAddrOffsetSectionItem(uint32_t Index,
                                                 uint64_t &Result) const {
   uint32_t Offset = AddrOffsetSectionBase + Index * getAddressByteSize();
   if (AddrOffsetSection->Data.size() < Offset + getAddressByteSize())
     return false;
-  DWARFDataExtractor DA(*AddrOffsetSection, isLittleEndian,
-                        getAddressByteSize());
+  DWARFDataExtractor DA(Context.getDWARFObj(), *AddrOffsetSection,
+                        isLittleEndian, getAddressByteSize());
   Result = DA.getRelocatedAddress(&Offset);
   return true;
 }
 
 bool DWARFUnit::getStringOffsetSectionItem(uint32_t Index,
                                            uint64_t &Result) const {
   unsigned ItemSize = getDwarfOffsetByteSize();
   uint32_t Offset = StringOffsetSectionBase + Index * ItemSize;
   if (StringOffsetSection.Data.size() < Offset + ItemSize)
     return false;
-  DWARFDataExtractor DA(StringOffsetSection, isLittleEndian, 0);
+  DWARFDataExtractor DA(Context.getDWARFObj(), StringOffsetSection,
+                        isLittleEndian, 0);
   Result = DA.getRelocatedValue(ItemSize, &Offset);
   return true;
 }
 
 bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
   Length = debug_info.getU32(offset_ptr);
   // FIXME: Support DWARF64.
   FormParams.Format = DWARF32;
bool DWARFUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
 
   return false;
 }
 
 bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
                                  DWARFDebugRangeList &RangeList) const {
   // Require that compile unit is extracted.
   assert(!DieArray.empty());
-  DWARFDataExtractor RangesData(*RangeSection, isLittleEndian,
-                                getAddressByteSize());
+  DWARFDataExtractor RangesData(Context.getDWARFObj(), *RangeSection,
+                                isLittleEndian, getAddressByteSize());
   uint32_t ActualRangeListOffset = RangeSectionBase + RangeListOffset;
   return RangeList.extract(RangesData, &ActualRangeListOffset);
 }
 
 void DWARFUnit::clear() {
   Offset = 0;
   Length = 0;
   Abbrevs = nullptr;

lib/DebugInfo/DWARF/DWARFVerifier.cpp

for (unsigned I = 0; I < NumDies; ++I) {
     }
   }
   return NumUnitErrors == 0;
 }
 
 bool DWARFVerifier::handleDebugInfo() {
   OS << "Verifying .debug_info Unit Header Chain...\n";
 
-  DWARFDataExtractor DebugInfoData(DCtx.getInfoSection(), DCtx.isLittleEndian(),
+  const DWARFObj &DObj = DCtx.getDWARFObj();
+  DWARFDataExtractor DebugInfoData(DObj, DObj.getInfoSection(), DCtx.isLittleEndian(),
                                    0);
   uint32_t NumDebugInfoErrors = 0;
   uint32_t OffsetStart = 0, Offset = 0, UnitIdx = 0;
   uint8_t UnitType = 0;
   bool isUnitDWARF64 = false;
   bool isHeaderChainValid = true;
   bool hasDIE = DebugInfoData.isValidOffset(Offset);
   while (hasDIE) {
     OffsetStart = Offset;
     if (!verifyUnitHeader(DebugInfoData, &Offset, UnitIdx, UnitType,
                           isUnitDWARF64)) {
       isHeaderChainValid = false;
       if (isUnitDWARF64)
         break;
     } else {
       std::unique_ptr<DWARFUnit> Unit;
       switch (UnitType) {
       case dwarf::DW_UT_type:
       case dwarf::DW_UT_split_type: {
         DWARFUnitSection<DWARFTypeUnit> TUSection{};
         Unit.reset(new DWARFTypeUnit(
-            DCtx, DCtx.getInfoSection(), DCtx.getDebugAbbrev(),
-            &DCtx.getRangeSection(), DCtx.getStringSection(),
-            DCtx.getStringOffsetSection(), &DCtx.getAppleObjCSection(),
-            DCtx.getLineSection(), DCtx.isLittleEndian(), false, TUSection,
+            DCtx, DObj.getInfoSection(), DCtx.getDebugAbbrev(),
+            &DObj.getRangeSection(), DObj.getStringSection(),
+            DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
+            DObj.getLineSection(), DCtx.isLittleEndian(), false, TUSection,
             nullptr));
         break;
       }
       case dwarf::DW_UT_skeleton:
       case dwarf::DW_UT_split_compile:
       case dwarf::DW_UT_compile:
       case dwarf::DW_UT_partial:
       // UnitType = 0 means that we are
       // verifying a compile unit in DWARF v4.
       case 0: {
         DWARFUnitSection<DWARFCompileUnit> CUSection{};
         Unit.reset(new DWARFCompileUnit(
-            DCtx, DCtx.getInfoSection(), DCtx.getDebugAbbrev(),
-            &DCtx.getRangeSection(), DCtx.getStringSection(),
-            DCtx.getStringOffsetSection(), &DCtx.getAppleObjCSection(),
-            DCtx.getLineSection(), DCtx.isLittleEndian(), false, CUSection,
+            DCtx, DObj.getInfoSection(), DCtx.getDebugAbbrev(),
+            &DObj.getRangeSection(), DObj.getStringSection(),
+            DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
+            DObj.getLineSection(), DCtx.isLittleEndian(), false, CUSection,
             nullptr));
         break;
       }
       default: { llvm_unreachable("Invalid UnitType."); }
       }
       Unit->extract(DebugInfoData, &OffsetStart);
       if (!verifyUnitContents(*Unit))
         ++NumDebugInfoErrors;
     }
     hasDIE = DebugInfoData.isValidOffset(Offset);
     ++UnitIdx;
   }
   if (UnitIdx == 0 && !hasDIE) {
     OS << "Warning: .debug_info is empty.\n";
     isHeaderChainValid = true;
   }
   NumDebugInfoErrors += verifyDebugInfoReferences();
   return (isHeaderChainValid && NumDebugInfoErrors == 0);
 }
 
 unsigned DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
                                                  DWARFAttribute &AttrValue) {
+  const DWARFObj &DObj = DCtx.getDWARFObj();
   unsigned NumErrors = 0;
   const auto Attr = AttrValue.Attr;
   switch (Attr) {
   case DW_AT_ranges:
     // Make sure the offset in the DW_AT_ranges attribute is valid.
     if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
-      if (*SectionOffset >= DCtx.getRangeSection().Data.size()) {
+      if (*SectionOffset >= DObj.getRangeSection().Data.size()) {
         ++NumErrors;
         OS << "error: DW_AT_ranges offset is beyond .debug_ranges "
               "bounds:\n";
         Die.dump(OS, 0);
         OS << "\n";
       }
     } else {
       ++NumErrors;
       OS << "error: DIE has invalid DW_AT_ranges encoding:\n";
       Die.dump(OS, 0);
       OS << "\n";
     }
     break;
   case DW_AT_stmt_list:
     // Make sure the offset in the DW_AT_stmt_list attribute is valid.
     if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
-      if (*SectionOffset >= DCtx.getLineSection().Data.size()) {
+      if (*SectionOffset >= DObj.getLineSection().Data.size()) {
         ++NumErrors;
         OS << "error: DW_AT_stmt_list offset is beyond .debug_line "
               "bounds: "
            << format("0x%08" PRIx32, *SectionOffset) << "\n";
         Die.dump(OS, 0);
         OS << "\n";
       }
     } else {
       ++NumErrors;
       OS << "error: DIE has invalid DW_AT_stmt_list encoding:\n";
       Die.dump(OS, 0);
       OS << "\n";
     }
     break;
 
   default:
     break;
   }
   return NumErrors;
 }
 
 unsigned DWARFVerifier::verifyDebugInfoForm(const DWARFDie &Die,
                                             DWARFAttribute &AttrValue) {
+  const DWARFObj &DObj = DCtx.getDWARFObj();
   unsigned NumErrors = 0;
   const auto Form = AttrValue.Value.getForm();
   switch (Form) {
   case DW_FORM_ref1:
   case DW_FORM_ref2:
   case DW_FORM_ref4:
   case DW_FORM_ref8:
   case DW_FORM_ref_udata: {
case DW_FORM_ref_udata: {
     break;
   }
   case DW_FORM_ref_addr: {
     // Verify all absolute DIE references have valid offsets in the
     // .debug_info section.
     Optional<uint64_t> RefVal = AttrValue.Value.getAsReference();
     assert(RefVal);
     if (RefVal) {
-      if (*RefVal >= DCtx.getInfoSection().Data.size()) {
+      if (*RefVal >= DObj.getInfoSection().Data.size()) {
         ++NumErrors;
         OS << "error: DW_FORM_ref_addr offset beyond .debug_info "
               "bounds:\n";
         Die.dump(OS, 0);
         OS << "\n";
       } else {
         // Valid reference, but we will verify it points to an actual
         // DIE later.
         ReferenceToDIEOffsets[*RefVal].insert(Die.getOffset());
       }
     }
     break;
   }
   case DW_FORM_strp: {
     auto SecOffset = AttrValue.Value.getAsSectionOffset();
     assert(SecOffset); // DW_FORM_strp is a section offset.
-    if (SecOffset && *SecOffset >= DCtx.getStringSection().size()) {
+    if (SecOffset && *SecOffset >= DObj.getStringSection().size()) {
       ++NumErrors;
       OS << "error: DW_FORM_strp offset beyond .debug_str bounds:\n";
       Die.dump(OS, 0);
       OS << "\n";
     }
     break;
   }
   default:
for (const auto &CU : DCtx.compile_units()) {
     // Get the attribute value as a section offset. No need to produce an
     // error here if the encoding isn't correct because we validate this in
     // the .debug_info verifier.
     auto StmtSectionOffset = toSectionOffset(Die.find(DW_AT_stmt_list));
     if (!StmtSectionOffset)
       continue;
     const uint32_t LineTableOffset = *StmtSectionOffset;
     auto LineTable = DCtx.getLineTableForUnit(CU.get());
-    if (LineTableOffset < DCtx.getLineSection().Data.size()) {
+    if (LineTableOffset < DCtx.getDWARFObj().getLineSection().Data.size()) {
       if (!LineTable) {
         ++NumDebugLineErrors;
         OS << "error: .debug_line[" << format("0x%08" PRIx32, LineTableOffset)
            << "] was not able to be parsed for CU:\n";
         Die.dump(OS, 0);
         OS << '\n';
         continue;
       }
bool DWARFVerifier::handleDebugLine() {
   OS << "Verifying .debug_line...\n";
   verifyDebugLineStmtOffsets();
   verifyDebugLineRows();
   return NumDebugLineErrors == 0;
 }
 
 bool DWARFVerifier::handleAppleNames() {
   NumAppleNamesErrors = 0;
-
-  DWARFDataExtractor AppleNamesSection(DCtx.getAppleNamesSection(),
+  const DWARFObj &D = DCtx.getDWARFObj();
+  DWARFDataExtractor AppleNamesSection(D, D.getAppleNamesSection(),
                                        DCtx.isLittleEndian(), 0);
-  DataExtractor StrData(DCtx.getStringSection(), DCtx.isLittleEndian(), 0);
+  DataExtractor StrData(D.getStringSection(), DCtx.isLittleEndian(), 0);
   DWARFAcceleratorTable AppleNames(AppleNamesSection, StrData);
 
   if (!AppleNames.extract()) {
     return true;
   }
 
   OS << "Verifying .apple_names...\n";
 

lib/DebugInfo/Symbolize/Symbolize.cpp

if (!EC && DebugInfo != nullptr && !PDBFileName.empty()) {
         Modules.insert(
             std::make_pair(ModuleName, std::unique_ptr<SymbolizableModule>()));
         return std::move(Err);
       }
       Context.reset(new PDBContext(*CoffObject, std::move(Session)));
     }
   }
   if (!Context)
-    Context.reset(new DWARFContextInMemory(*Objects.second));
+    Context = DWARFContext::create(*Objects.second);
   assert(Context);
   auto InfoOrErr =
       SymbolizableObjectFile::create(Objects.first, std::move(Context));
   std::unique_ptr<SymbolizableModule> SymMod;
   if (InfoOrErr)
     SymMod = std::move(InfoOrErr.get());
   auto InsertResult =
       Modules.insert(std::make_pair(ModuleName, std::move(SymMod)));

tools/dsymutil/DwarfLinker.cpp

void DwarfStreamer::emitLocationsForUnit(const CompileUnit &Unit,
   const auto &Attributes = Unit.getLocationAttributes();
 
   if (Attributes.empty())
     return;
 
   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection());
 
   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
-  const DWARFSection &InputSec = Dwarf.getLocSection();
+  const DWARFSection &InputSec = Dwarf.getDWARFObj().getLocSection();
   DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(), AddressSize);
   DWARFUnit &OrigUnit = Unit.getOrigUnit();
   auto OrigUnitDie = OrigUnit.getUnitDIE(false);
   int64_t UnitPcOffset = 0;
   if (auto OrigLowPc = dwarf::toAddress(OrigUnitDie.find(dwarf::DW_AT_low_pc)))
     UnitPcOffset = int64_t(*OrigLowPc) - Unit.getLowPc();
 
   for (const auto &Attr : Attributes) {
public:
     /// \returns the root of the cloned tree or null if nothing was selected.
     DIE *cloneDIE(const DWARFDie &InputDIE, CompileUnit &U,
                   int64_t PCOffset, uint32_t OutOffset, unsigned Flags,
                   DIE *Die = nullptr);
 
     /// Construct the output DIE tree by cloning the DIEs we
     /// chose to keep above. If there are no valid relocs, then there's
     /// nothing to clone/emit.
-    void cloneAllCompileUnits(DWARFContextInMemory &DwarfContext);
+    void cloneAllCompileUnits(DWARFContext &DwarfContext);
 
   private:
     typedef DWARFAbbreviationDeclaration::AttributeSpec AttributeSpec;
 
     /// Information gathered and exchanged between the various
     /// clone*Attributes helpers about the attributes of a particular DIE.
     struct AttributesInfo {
       const char *Name, *MangledName;         ///< Names.

 /// \brief Patch the input object file relevant debug_ranges entries
 /// and emit them in the output file. Update the relevant attributes
 /// to point at the new entries.
 void DwarfLinker::patchRangesForUnit(const CompileUnit &Unit,
                                      DWARFContext &OrigDwarf) const {
   DWARFDebugRangeList RangeList;
   const auto &FunctionRanges = Unit.getFunctionRanges();
   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
-  DWARFDataExtractor RangeExtractor(OrigDwarf.getRangeSection(),
+  DWARFDataExtractor RangeExtractor(OrigDwarf.getDWARFObj(),
+                                    OrigDwarf.getDWARFObj().getRangeSection(),
                                     OrigDwarf.isLittleEndian(), AddressSize);
   auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange;
   DWARFUnit &OrigUnit = Unit.getOrigUnit();
   auto OrigUnitDie = OrigUnit.getUnitDIE(false);
   uint64_t OrigLowPc = dwarf::toAddress(OrigUnitDie.find(dwarf::DW_AT_low_pc), -1ULL);
   // Ranges addresses are based on the unit's low_pc. Compute the
   // offset we need to apply to adapt to the new unit's low_pc.
   int64_t UnitPcOffset = 0;
void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
 
   // Update the cloned DW_AT_stmt_list with the correct debug_line offset.
   if (auto *OutputDIE = Unit.getOutputUnitDIE())
     patchStmtList(*OutputDIE, DIEInteger(Streamer->getLineSectionSize()));
 
   // Parse the original line info for the unit.
   DWARFDebugLine::LineTable LineTable;
   uint32_t StmtOffset = *StmtList;
-  DWARFDataExtractor LineExtractor(OrigDwarf.getLineSection(),
-                                   OrigDwarf.isLittleEndian(),
-                                   Unit.getOrigUnit().getAddressByteSize());
+  DWARFDataExtractor LineExtractor(
+      OrigDwarf.getDWARFObj(), OrigDwarf.getDWARFObj().getLineSection(),
+      OrigDwarf.isLittleEndian(), Unit.getOrigUnit().getAddressByteSize());
   LineTable.parse(LineExtractor, &StmtOffset);
 
   // This vector is the output line table.
   std::vector<DWARFDebugLine::Row> NewRows;
   NewRows.reserve(LineTable.Rows.size());
 
   // Current sequence of rows being extracted, before being inserted
   // in NewRows.
void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
   // prologue over and that works because we act as both producer and
   // consumer. It would be nicer to have a real configurable line
   // table emitter.
   if (LineTable.Prologue.getVersion() != 2 ||
       LineTable.Prologue.DefaultIsStmt != DWARF2_LINE_DEFAULT_IS_STMT ||
       LineTable.Prologue.OpcodeBase > 13)
     reportWarning("line table parameters mismatch. Cannot emit.");
   else {
-    StringRef LineData = OrigDwarf.getLineSection().Data;
+    StringRef LineData = OrigDwarf.getDWARFObj().getLineSection().Data;
     MCDwarfLineTableParams Params;
     Params.DWARF2LineOpcodeBase = LineTable.Prologue.OpcodeBase;
     Params.DWARF2LineBase = LineTable.Prologue.LineBase;
     Params.DWARF2LineRange = LineTable.Prologue.LineRange;
     Streamer->emitLineTableForUnit(Params,
                                    LineData.slice(*StmtList + 4, PrologueEnd),
                                    LineTable.Prologue.MinInstLength, NewRows,
                                    Unit.getOrigUnit().getAddressByteSize());

 /// patched frame descriptions for the linked binary.
 ///
 /// This is actually pretty easy as the data of the CIEs and FDEs can
 /// be considered as black boxes and moved as is. The only thing to do
 /// is to patch the addresses in the headers.
 void DwarfLinker::patchFrameInfoForObject(const DebugMapObject &DMO,
                                           DWARFContext &OrigDwarf,
                                           unsigned AddrSize) {
-  StringRef FrameData = OrigDwarf.getDebugFrameSection();
+  StringRef FrameData = OrigDwarf.getDWARFObj().getDebugFrameSection();
   if (FrameData.empty())
     return;
 
   DataExtractor Data(FrameData, OrigDwarf.isLittleEndian(), 0);
   uint32_t InputOffset = 0;
 
   // Store the data of the CIEs defined in this object, keyed by their
   // offsets.
if (isClangModule) {
       }
     }
     return;
   }
 
   std::unique_ptr<CompileUnit> Unit;
 
   // Setup access to the debug info.
-  DWARFContextInMemory DwarfContext(*ErrOrObj);
+  auto DwarfContext = DWARFContext::create(*ErrOrObj);
   RelocationManager RelocMgr(*this);
-  for (const auto &CU : DwarfContext.compile_units()) {
+  for (const auto &CU : DwarfContext->compile_units()) {
     auto CUDie = CU->getUnitDIE(false);
     // Recursively get all modules imported by this one.
     if (!registerModuleReference(CUDie, *CU, ModuleMap, Indent)) {
       if (Unit) {
         errs() << Filename << ": Clang modules are expected to have exactly"
                << " 1 compile unit.\n";
         exitDsymutil(1);
       }
void DwarfLinker::loadClangModule(StringRef Filename, StringRef ModulePath,
   if (Options.Verbose) {
     outs().indent(Indent);
     outs() << "cloning .debug_info from " << Filename << "\n";
   }
 
   std::vector<std::unique_ptr<CompileUnit>> CompileUnits;
   CompileUnits.push_back(std::move(Unit));
   DIECloner(*this, RelocMgr, DIEAlloc, CompileUnits, Options)
-      .cloneAllCompileUnits(DwarfContext);
+      .cloneAllCompileUnits(*DwarfContext);
 }
 
-void DwarfLinker::DIECloner::cloneAllCompileUnits(
-    DWARFContextInMemory &DwarfContext) {
+void DwarfLinker::DIECloner::cloneAllCompileUnits(DWARFContext &DwarfContext) {
   if (!Linker.Streamer)
     return;
 
   for (auto &CurrentUnit : CompileUnits) {
     auto InputDIE = CurrentUnit->getOrigUnit().getUnitDIE();
     CurrentUnit->setStartOffset(Linker.OutputDebugInfoSize);
     if (CurrentUnit->getInfo(0).Keep) {
       // Clone the InputDIE into your Unit DIE in our compile unit since it
for (const auto &Obj : Map.objects()) {
     RelocationManager RelocMgr(*this);
     if (!RelocMgr.findValidRelocsInDebugInfo(*ErrOrObj, *Obj)) {
       if (Options.Verbose)
         outs() << "No valid relocations found. Skipping.\n";
       continue;
     }
 
     // Setup access to the debug info.
-    DWARFContextInMemory DwarfContext(*ErrOrObj);
-    startDebugObject(DwarfContext, *Obj);
+    auto DwarfContext = DWARFContext::create(*ErrOrObj);
+    startDebugObject(*DwarfContext, *Obj);
 
     // In a first phase, just read in the debug info and load all clang modules.
-    for (const auto &CU : DwarfContext.compile_units()) {
+    for (const auto &CU : DwarfContext->compile_units()) {
       auto CUDie = CU->getUnitDIE(false);
       if (Options.Verbose) {
         outs() << "Input compilation unit:";
         CUDie.dump(outs(), 0);
       }
 
       if (!registerModuleReference(CUDie, *CU, ModuleMap)) {
         Units.push_back(llvm::make_unique<CompileUnit>(*CU, UnitID++,
for (auto &CurrentUnit : Units)
                         *CurrentUnit, 0);
 
     // The calls to applyValidRelocs inside cloneDIE will walk the
     // reloc array again (in the same way findValidRelocsInDebugInfo()
     // did). We need to reset the NextValidReloc index to the beginning.
     RelocMgr.resetValidRelocs();
     if (RelocMgr.hasValidRelocs())
       DIECloner(*this, RelocMgr, DIEAlloc, Units, Options)
-          .cloneAllCompileUnits(DwarfContext);
+          .cloneAllCompileUnits(*DwarfContext);
     if (!Options.NoOutput && !Units.empty())
-      patchFrameInfoForObject(*Obj, DwarfContext,
+      patchFrameInfoForObject(*Obj, *DwarfContext,
                               Units[0]->getOrigUnit().getAddressByteSize());
 
     // Clean-up before starting working on the next object.
     endDebugObject();
   }
 
   // Emit everything that's global.
   if (!Options.NoOutput) {

tools/llvm-dwarfdump/llvm-dwarfdump.cpp

 static void error(StringRef Filename, std::error_code EC) {
   if (!EC)
     return;
   errs() << Filename << ": " << EC.message() << "\n";
   exit(1);
 }
 
 static void DumpObjectFile(ObjectFile &Obj, Twine Filename) {
-  std::unique_ptr<DIContext> DICtx(new DWARFContextInMemory(Obj));
+  std::unique_ptr<DIContext> DICtx = DWARFContext::create(Obj);
 
   outs() << Filename.str() << ":\tfile format " << Obj.getFileFormatName()
          << "\n\n";
 
 
   // Dump the complete DWARF structure.
   DIDumpOptions DumpOpts;
   DumpOpts.DumpType = DumpType;
for (auto &ObjForArch : Fat->objects()) {
       auto MachOOrErr = ObjForArch.getAsObjectFile();
       error(Filename, errorToErrorCode(MachOOrErr.takeError()));
       DumpObjectFile(**MachOOrErr,
                      Filename + " (" + ObjForArch.getArchFlagName() + ")");
     }
 }
 
 static bool VerifyObjectFile(ObjectFile &Obj, Twine Filename) {
-  std::unique_ptr<DIContext> DICtx(new DWARFContextInMemory(Obj));
-  
+  std::unique_ptr<DIContext> DICtx = DWARFContext::create(Obj);
   // Verify the DWARF and exit with non-zero exit status if verification
   // fails.
   raw_ostream &stream = Quiet ? nulls() : outs();
   stream << "Verifying " << Filename.str() << ":\tfile format "
   << Obj.getFileFormatName() << "\n";
   bool Result = DICtx->verify(stream, DumpType);
   if (Result)
     stream << "No errors.\n";

tools/llvm-objdump/MachODump.cpp

static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
   if (Bind)
     printBindTable(MachOOF);
   if (LazyBind)
     printLazyBindTable(MachOOF);
   if (WeakBind)
     printWeakBindTable(MachOOF);
 
   if (DwarfDumpType != DIDT_Null) {
-    std::unique_ptr<DIContext> DICtx(new DWARFContextInMemory(*MachOOF));
+    std::unique_ptr<DIContext> DICtx = DWARFContext::create(*MachOOF);
     // Dump the complete DWARF structure.
     DIDumpOptions DumpOpts;
     DumpOpts.DumpType = DwarfDumpType;
     DumpOpts.DumpEH = true;
     DICtx->dump(outs(), DumpOpts);
   }
 }
 
if (!DSYMFile.empty()) {
       }
       DbgObj =
           ObjectFile::createMachOObjectFile(BufOrErr.get()->getMemBufferRef())
               .get()
               .release();
     }
 
     // Setup the DIContext
-    diContext.reset(new DWARFContextInMemory(*DbgObj));
+    diContext = DWARFContext::create(*DbgObj);
   }
 
   if (FilterSections.size() == 0)
     outs() << "(" << DisSegName << "," << DisSectName << ") section\n";
 
   for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
     StringRef SectName;
     if (Sections[SectIdx].getName(SectName) || SectName != DisSectName)

tools/llvm-objdump/llvm-objdump.cpp

 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cctype>
 #include <cstring>
 #include <system_error>
-#include <utility>
 #include <unordered_map>
+#include <utility>
 
 using namespace llvm;
 using namespace object;
 
 static cl::list<std::string>
 InputFilenames(cl::Positional, cl::desc("<input object files>"),cl::ZeroOrMore);
 
 cl::opt<bool>
if (LazyBind)
     printLazyBindTable(o);
   if (WeakBind)
     printWeakBindTable(o);
   if (RawClangAST)
     printRawClangAST(o);
   if (PrintFaultMaps)
     printFaultMaps(o);
   if (DwarfDumpType != DIDT_Null) {
-    std::unique_ptr<DIContext> DICtx(new DWARFContextInMemory(*o));
+    std::unique_ptr<DIContext> DICtx = DWARFContext::create(*o);
     // Dump the complete DWARF structure.
     DIDumpOptions DumpOpts;
     DumpOpts.DumpType = DwarfDumpType;
     DumpOpts.DumpEH = true;
     DICtx->dump(outs(), DumpOpts);
   }
 }
 

tools/llvm-rtdyld/llvm-rtdyld.cpp

if (LoadObjects) {
 
       if (UseDebugObj) {
         DebugObj = LoadedObjInfo->getObjectForDebug(Obj);
         SymbolObj = DebugObj.getBinary();
         LoadedObjInfo.reset();
       }
     }
 
-    std::unique_ptr<DIContext> Context(
-      new DWARFContextInMemory(*SymbolObj,LoadedObjInfo.get()));
+    std::unique_ptr<DIContext> Context =
+        DWARFContext::create(*SymbolObj, LoadedObjInfo.get());
 
     std::vector<std::pair<SymbolRef, uint64_t>> SymAddr =
         object::computeSymbolSizes(*SymbolObj);
 
     // Use symbol info to iterate functions in the object.
     for (const auto &P : SymAddr) {
       object::SymbolRef Sym = P.first;
       Expected<SymbolRef::Type> TypeOrErr = Sym.getType();

tools/obj2yaml/dwarf2yaml.cpp

 
 void dumpInitialLength(DataExtractor &Data, uint32_t &Offset,
                        DWARFYAML::InitialLength &InitialLength) {
   InitialLength.TotalLength = Data.getU32(&Offset);
   if (InitialLength.isDWARF64())
     InitialLength.TotalLength64 = Data.getU64(&Offset);
 }
 
-void dumpDebugAbbrev(DWARFContextInMemory &DCtx, DWARFYAML::Data &Y) {
+void dumpDebugAbbrev(DWARFContext &DCtx, DWARFYAML::Data &Y) {
   auto AbbrevSetPtr = DCtx.getDebugAbbrev();
   if (AbbrevSetPtr) {
     for (auto AbbrvDeclSet : *AbbrevSetPtr) {
       for (auto AbbrvDecl : AbbrvDeclSet.second) {
         DWARFYAML::Abbrev Abbrv;
         Abbrv.Code = AbbrvDecl.getCode();
         Abbrv.Tag = AbbrvDecl.getTag();
         Abbrv.Children = AbbrvDecl.hasChildren() ? dwarf::DW_CHILDREN_yes
                                                  : dwarf::DW_CHILDREN_no;
         for (auto Attribute : AbbrvDecl.attributes()) {
           DWARFYAML::AttributeAbbrev AttAbrv;
           AttAbrv.Attribute = Attribute.Attr;
           AttAbrv.Form = Attribute.Form;
           if (AttAbrv.Form == dwarf::DW_FORM_implicit_const)
             AttAbrv.Value = *Attribute.ByteSizeOrValue;
           Abbrv.Attributes.push_back(AttAbrv);
         }
         Y.AbbrevDecls.push_back(Abbrv);
       }
     }
   }
 }
 
-void dumpDebugStrings(DWARFContextInMemory &DCtx, DWARFYAML::Data &Y) {
-  StringRef RemainingTable = DCtx.getStringSection();
+void dumpDebugStrings(DWARFContext &DCtx, DWARFYAML::Data &Y) {
+  StringRef RemainingTable = DCtx.getDWARFObj().getStringSection();
   while (RemainingTable.size() > 0) {
     auto SymbolPair = RemainingTable.split('\0');
     RemainingTable = SymbolPair.second;
     Y.DebugStrings.push_back(SymbolPair.first);
   }
 }
 
-void dumpDebugARanges(DWARFContextInMemory &DCtx, DWARFYAML::Data &Y) {
-  DataExtractor ArangesData(DCtx.getARangeSection(), DCtx.isLittleEndian(), 0);
+void dumpDebugARanges(DWARFContext &DCtx, DWARFYAML::Data &Y) {
+  DataExtractor ArangesData(DCtx.getDWARFObj().getARangeSection(),
+                            DCtx.isLittleEndian(), 0);
   uint32_t Offset = 0;
   DWARFDebugArangeSet Set;
 
   while (Set.extract(ArangesData, &Offset)) {
     DWARFYAML::ARange Range;
     Range.Length.setLength(Set.getHeader().Length);
     Range.Version = Set.getHeader().Version;
     Range.CuOffset = Set.getHeader().CuOffset;
     Range.AddrSize = Set.getHeader().AddrSize;
     Range.SegSize = Set.getHeader().SegSize;
     for (auto Descriptor : Set.descriptors()) {
       DWARFYAML::ARangeDescriptor Desc;
       Desc.Address = Descriptor.Address;
       Desc.Length = Descriptor.Length;
       Range.Descriptors.push_back(Desc);
     }
     Y.ARanges.push_back(Range);
   }
 }
 
-void dumpPubSection(DWARFContextInMemory &DCtx, DWARFYAML::PubSection &Y,
+void dumpPubSection(DWARFContext &DCtx, DWARFYAML::PubSection &Y,
                     StringRef Section) {
   DataExtractor PubSectionData(Section, DCtx.isLittleEndian(), 0);
   uint32_t Offset = 0;
   dumpInitialLength(PubSectionData, Offset, Y.Length);
   Y.Version = PubSectionData.getU16(&Offset);
   Y.UnitOffset = PubSectionData.getU32(&Offset);
   Y.UnitSize = PubSectionData.getU32(&Offset);
   while (Offset < Y.Length.getLength()) {
     DWARFYAML::PubEntry NewEntry;
     NewEntry.DieOffset = PubSectionData.getU32(&Offset);
     if (Y.IsGNUStyle)
       NewEntry.Descriptor = PubSectionData.getU8(&Offset);
     NewEntry.Name = PubSectionData.getCStr(&Offset);
     Y.Entries.push_back(NewEntry);
   }
 }
 
-void dumpDebugPubSections(DWARFContextInMemory &DCtx, DWARFYAML::Data &Y) {
+void dumpDebugPubSections(DWARFContext &DCtx, DWARFYAML::Data &Y) {
+  const DWARFObj &D = DCtx.getDWARFObj();
   Y.PubNames.IsGNUStyle = false;
-  dumpPubSection(DCtx, Y.PubNames, DCtx.getPubNamesSection());
+  dumpPubSection(DCtx, Y.PubNames, D.getPubNamesSection());
 
   Y.PubTypes.IsGNUStyle = false;
-  dumpPubSection(DCtx, Y.PubTypes, DCtx.getPubTypesSection());
+  dumpPubSection(DCtx, Y.PubTypes, D.getPubTypesSection());
 
   Y.GNUPubNames.IsGNUStyle = true;
-  dumpPubSection(DCtx, Y.GNUPubNames, DCtx.getGnuPubNamesSection());
+  dumpPubSection(DCtx, Y.GNUPubNames, D.getGnuPubNamesSection());
 
   Y.GNUPubTypes.IsGNUStyle = true;
-  dumpPubSection(DCtx, Y.GNUPubTypes, DCtx.getGnuPubTypesSection());
+  dumpPubSection(DCtx, Y.GNUPubTypes, D.getGnuPubTypesSection());
 }
 
-void dumpDebugInfo(DWARFContextInMemory &DCtx, DWARFYAML::Data &Y) {
+void dumpDebugInfo(DWARFContext &DCtx, DWARFYAML::Data &Y) {
   for (const auto &CU : DCtx.compile_units()) {
     DWARFYAML::Unit NewUnit;
     NewUnit.Length.setLength(CU->getLength());
     NewUnit.Version = CU->getVersion();
     if(NewUnit.Version >= 5)
       NewUnit.Type = (dwarf::UnitType)CU->getUnitType();
     NewUnit.AbbrOffset = CU->getAbbreviations()->getOffset();
     NewUnit.AddrSize = CU->getAddressByteSize();
bool dumpFileEntry(DataExtractor &Data, uint32_t &Offset,
   if (File.Name.empty())
     return false;
   File.DirIdx = Data.getULEB128(&Offset);
   File.ModTime = Data.getULEB128(&Offset);
   File.Length = Data.getULEB128(&Offset);
   return true;
 }
 
-void dumpDebugLines(DWARFContextInMemory &DCtx, DWARFYAML::Data &Y) {
+void dumpDebugLines(DWARFContext &DCtx, DWARFYAML::Data &Y) {
   for (const auto &CU : DCtx.compile_units()) {
     auto CUDIE = CU->getUnitDIE();
     if (!CUDIE)
       continue;
     if (auto StmtOffset =
             dwarf::toSectionOffset(CUDIE.find(dwarf::DW_AT_stmt_list))) {
       DWARFYAML::LineTable DebugLines;
-      DataExtractor LineData(DCtx.getLineSection().Data, DCtx.isLittleEndian(),
-                             CU->getAddressByteSize());
+      DataExtractor LineData(DCtx.getDWARFObj().getLineSection().Data,
+                             DCtx.isLittleEndian(), CU->getAddressByteSize());
       uint32_t Offset = *StmtOffset;
       dumpInitialLength(LineData, Offset, DebugLines.Length);
       uint64_t LineTableLength = DebugLines.Length.getLength();
       uint64_t SizeOfPrologueLength = DebugLines.Length.isDWARF64() ? 8 : 4;
       DebugLines.Version = LineData.getU16(&Offset);
       DebugLines.PrologueLength =
           LineData.getUnsigned(&Offset, SizeOfPrologueLength);
       const uint64_t EndPrologue = DebugLines.PrologueLength + Offset;
if (auto StmtOffset =
         }
         DebugLines.Opcodes.push_back(NewOp);
       }
       Y.DebugLines.push_back(DebugLines);
     }
   }
 }
 
-std::error_code dwarf2yaml(DWARFContextInMemory &DCtx, DWARFYAML::Data &Y) {
+std::error_code dwarf2yaml(DWARFContext &DCtx, DWARFYAML::Data &Y) {
   dumpDebugAbbrev(DCtx, Y);
   dumpDebugStrings(DCtx, Y);
   dumpDebugARanges(DCtx, Y);
   dumpDebugPubSections(DCtx, Y);
   dumpDebugInfo(DCtx, Y);
   dumpDebugLines(DCtx, Y);
   return obj2yaml_error::success;
 }

tools/obj2yaml/macho2yaml.cpp

class MachODumper {
   void dumpHeader(std::unique_ptr<MachOYAML::Object> &Y);
   void dumpLoadCommands(std::unique_ptr<MachOYAML::Object> &Y);
   void dumpLinkEdit(std::unique_ptr<MachOYAML::Object> &Y);
   void dumpRebaseOpcodes(std::unique_ptr<MachOYAML::Object> &Y);
   void dumpBindOpcodes(std::vector<MachOYAML::BindOpcode> &BindOpcodes,
                        ArrayRef<uint8_t> OpcodeBuffer, bool Lazy = false);
   void dumpExportTrie(std::unique_ptr<MachOYAML::Object> &Y);
   void dumpSymbols(std::unique_ptr<MachOYAML::Object> &Y);
-  void dumpDebugAbbrev(DWARFContextInMemory &DCtx,
+  void dumpDebugAbbrev(DWARFContext &DCtx,
                        std::unique_ptr<MachOYAML::Object> &Y);
-  void dumpDebugStrings(DWARFContextInMemory &DCtx,
+  void dumpDebugStrings(DWARFContext &DCtx,
                         std::unique_ptr<MachOYAML::Object> &Y);
 
 public:
   MachODumper(const object::MachOObjectFile &O) : Obj(O) {}
   Expected<std::unique_ptr<MachOYAML::Object>> dump();
 };
 
 #define HANDLE_LOAD_COMMAND(LCName, LCValue, LCStruct)                         \

 
 Expected<std::unique_ptr<MachOYAML::Object>> MachODumper::dump() {
   auto Y = make_unique<MachOYAML::Object>();
   Y->IsLittleEndian = Obj.isLittleEndian();
   dumpHeader(Y);
   dumpLoadCommands(Y);
   dumpLinkEdit(Y);
 
-  DWARFContextInMemory DICtx(Obj);
-  if (auto Err = dwarf2yaml(DICtx, Y->DWARF))
+  std::unique_ptr<DWARFContext> DICtx = DWARFContext::create(Obj);
+  if (auto Err = dwarf2yaml(*DICtx, Y->DWARF))
     return errorCodeToError(Err);
   return std::move(Y);
 }
 
 void MachODumper::dumpHeader(std::unique_ptr<MachOYAML::Object> &Y) {
   Y->Header.magic = Obj.getHeader().magic;
   Y->Header.cputype = Obj.getHeader().cputype;
   Y->Header.cpusubtype = Obj.getHeader().cpusubtype;

tools/obj2yaml/obj2yaml.h

std::error_code elf2yaml(llvm::raw_ostream &Out,
                          const llvm::object::ObjectFile &Obj);
 std::error_code macho2yaml(llvm::raw_ostream &Out,
                            const llvm::object::Binary &Obj);
 std::error_code wasm2yaml(llvm::raw_ostream &Out,
                           const llvm::object::WasmObjectFile &Obj);
 
 // Forward decls for dwarf2yaml
 namespace llvm {
-class DWARFContextInMemory;
+class DWARFContext;
 namespace DWARFYAML {
 struct Data;
 }
 }
 
-std::error_code dwarf2yaml(llvm::DWARFContextInMemory &DCtx,
-                           llvm::DWARFYAML::Data &Y);
+std::error_code dwarf2yaml(llvm::DWARFContext &DCtx, llvm::DWARFYAML::Data &Y);
 
 #endif

unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp

 //===- llvm/unittest/DebugInfo/DWARFFormValueTest.cpp ---------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "DwarfGenerator.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/BinaryFormat/Dwarf.h"
-#include "llvm/Config/llvm-config.h"
 #include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/Config/llvm-config.h"
 #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/ObjectYAML/DWARFEmitter.h"
 #include "llvm/ObjectYAML/DWARFYAML.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
 #include "llvm/Testing/Support/Error.h"
 #include "gtest/gtest.h"
 #include <climits>
 #include <cstdint>
 #include <cstring>
 #include <string>
 
 using namespace llvm;
#define UDATA_1 18446744073709551614ULL
 
   //----------------------------------------------------------------------
   // Generate the DWARF
   //----------------------------------------------------------------------
   StringRef FileBytes = DG->generate();
   MemoryBufferRef FileBuffer(FileBytes, "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
   auto DieDG = U->getUnitDIE(false);
   EXPECT_TRUE(DieDG.isValid());
 
   //----------------------------------------------------------------------
   // Test address forms
   //----------------------------------------------------------------------
   EXPECT_EQ(AddrValue, toAddress(DieDG.find(Attr_DW_FORM_addr), 0));
 
template <uint16_t Version, class AddrType> void TestChildren() {
   ArgcDie.addAttribute(DW_AT_name, DW_FORM_strp, "argc");
   // ArgcDie.addAttribute(DW_AT_type, DW_FORM_ref4, IntDie);
   ArgcDie.addAttribute(DW_AT_type, DW_FORM_ref_addr, IntDie);
 
   StringRef FileBytes = DG->generate();
   MemoryBufferRef FileBuffer(FileBytes, "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto DieDG = U->getUnitDIE(false);
   EXPECT_TRUE(DieDG.isValid());
 
   // Verify the first child of the compile unit DIE is our subprogram.
   auto SubprogramDieDG = DieDG.getFirstChild();
   EXPECT_TRUE(SubprogramDieDG.isValid());
template <uint16_t Version, class AddrType> void TestReferences() {
   dwarfgen::DIE CU1ToCU2RefAddrDie = CU1Die.addChild(DW_TAG_variable);
   CU1ToCU2RefAddrDie.addAttribute(DW_AT_name, DW_FORM_strp, "CU1ToCU2RefAddr");
   CU1ToCU2RefAddrDie.addAttribute(DW_AT_type, DW_FORM_ref_addr, CU2TypeDie);
 
   StringRef FileBytes = DG->generate();
   MemoryBufferRef FileBuffer(FileBytes, "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 2u);
-  DWARFCompileUnit *U1 = DwarfContext.getCompileUnitAtIndex(0);
-  DWARFCompileUnit *U2 = DwarfContext.getCompileUnitAtIndex(1);
+  DWARFCompileUnit *U1 = DwarfContext->getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U2 = DwarfContext->getCompileUnitAtIndex(1);
 
   // Get the compile unit DIE is valid.
   auto Unit1DieDG = U1->getUnitDIE(false);
   EXPECT_TRUE(Unit1DieDG.isValid());
 
   auto Unit2DieDG = U2->getUnitDIE(false);
   EXPECT_TRUE(Unit2DieDG.isValid());
 
SubprogramLowHighPC.addAttribute(DW_AT_high_pc, DW_FORM_data4,
                                      ActualHighPCOffset);
   else
     SubprogramLowHighPC.addAttribute(DW_AT_high_pc, DW_FORM_addr, ActualHighPC);
 
   StringRef FileBytes = DG->generate();
   MemoryBufferRef FileBuffer(FileBytes, "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto DieDG = U->getUnitDIE(false);
   EXPECT_TRUE(DieDG.isValid());
 
   uint64_t LowPC, HighPC, SectionIndex;
   Optional<uint64_t> OptU64;
   // Verify the that our subprogram with no PC value fails appropriately when
// Scope to allow us to re-use the same DIE names
     C.addChild((dwarf::Tag)Tag::C1);
     C.addChild((dwarf::Tag)Tag::C2);
     D.addChild((dwarf::Tag)Tag::D1);
   }
 
   MemoryBufferRef FileBuffer(DG->generate(), "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto CUDie = U->getUnitDIE(false);
   EXPECT_TRUE(CUDie.isValid());
 
   // The compile unit doesn't have a parent or a sibling.
   auto ParentDie = CUDie.getParent();
   EXPECT_FALSE(ParentDie.isValid());
// Scope to allow us to re-use the same DIE names
     auto CUDie = CU.getUnitDIE();
     CUDie.addChild((dwarf::Tag)Tag::A);
     CUDie.addChild((dwarf::Tag)Tag::B);
   }
 
   MemoryBufferRef FileBuffer(DG->generate(), "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto CUDie = U->getUnitDIE(false);
   EXPECT_TRUE(CUDie.isValid());
   uint32_t Index;
   DWARFDie A;
   DWARFDie B;
 
const char *yamldata = "debug_abbrev:\n"
                          "    Entries:\n"
                          "      - AbbrCode:        0x00000001\n"
                          "        Values:\n"
                          "      - AbbrCode:        0x00000000\n"
                          "        Values:\n";
 
   auto ErrOrSections = DWARFYAML::EmitDebugSections(StringRef(yamldata));
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto CUDie = U->getUnitDIE(false);
   EXPECT_TRUE(CUDie.isValid());
 
   // Verify that the CU Die that says it has children, but doesn't, actually
   // has begin and end iterators that are equal. We want to make sure we don't
   // see the Null DIEs during iteration.
// Scope to allow us to re-use the same DIE names
     CUDie.addAttribute(DW_AT_declaration, DW_FORM_flag_present);
     // Encode an attribute value after an attribute with no data.
     CUDie.addAttribute(DW_AT_low_pc, DW_FORM_addr, CULowPC);
   }
 
   MemoryBufferRef FileBuffer(DG->generate(), "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto CUDie = U->getUnitDIE(false);
   EXPECT_TRUE(CUDie.isValid());
 
   auto R = CUDie.attributes();
   auto I = R.begin();
   auto E = R.end();
// Scope to allow us to re-use the same DIE names
     FuncDie.addAttribute(DW_AT_abstract_origin, DW_FORM_ref4, FuncAbsDie);
     VarAbsDie.addAttribute(DW_AT_name, DW_FORM_strp, AbsDieName);
     VarDie.addAttribute(DW_AT_abstract_origin, DW_FORM_ref4, VarAbsDie);
   }
 
   MemoryBufferRef FileBuffer(DG->generate(), "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto CUDie = U->getUnitDIE(false);
   EXPECT_TRUE(CUDie.isValid());
 
   auto FuncSpecDie = CUDie.getFirstChild();
   auto FuncAbsDie = FuncSpecDie.getSibling();
   auto FuncDie = FuncAbsDie.getSibling();
// Scope to allow us to re-use the same DIE names
     auto FuncDie = CUDie.addChild(DW_TAG_subprogram);
     FuncSpecDie.addAttribute(DW_AT_MIPS_linkage_name, DW_FORM_strp, DieMangled);
     FuncDie.addAttribute(DW_AT_specification, DW_FORM_ref4, FuncSpecDie);
   }
 
   MemoryBufferRef FileBuffer(DG->generate(), "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
 
   // Verify the number of compile units is correct.
-  uint32_t NumCUs = DwarfContext.getNumCompileUnits();
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
   auto CUDie = U->getUnitDIE(false);
   EXPECT_TRUE(CUDie.isValid());
 
   auto FuncSpecDie = CUDie.getFirstChild();
   auto FuncDie = FuncSpecDie.getSibling();
 
TEST(DWARFDebugInfo, TestImplicitConstAbbrevs) {
   SecondVal1DIE.addAttribute(Attr, DW_FORM_implicit_const, Val1);
 
   auto Val2DIE = CUDie.addChild(DW_TAG_class_type);
   Val2DIE.addAttribute(Attr, DW_FORM_implicit_const, Val2);
 
   MemoryBufferRef FileBuffer(DG->generate(), "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
-  DWARFContextInMemory DwarfContext(*Obj.get());
-  DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(*Obj.get());
+  DWARFCompileUnit *U = DwarfContext->getCompileUnitAtIndex(0);
   EXPECT_TRUE((bool)U);
 
   const auto *Abbrevs = U->getAbbreviations();
   EXPECT_TRUE((bool)Abbrevs);
 
   // Let's find implicit_const abbrevs and verify,
   // that there are exactly two of them and both of them
   // can be dumped correctly.
debug_info:
             Values:
               - Value:           0x000000000000000D
               - Value:           0x0000000000001234
           - AbbrCode:        0x00000000
             Values:
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(StringRef(yamldata));
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
-  VerifyError(DwarfContext, "error: DW_FORM_ref4 CU offset 0x00001234 is "
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
+  VerifyError(*DwarfContext, "error: DW_FORM_ref4 CU offset 0x00001234 is "
                              "invalid (must be less than CU size of "
                              "0x0000001a):");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyInvalidRefAddr) {
   // Create a single compile unit with a single function that has an invalid
   // DW_AT_type with an invalid .debug_info offset in its DW_FORM_ref_addr.
   const char *yamldata = R"(
     debug_str:
       - ''
debug_info:
             Values:
               - Value:           0x000000000000000D
               - Value:           0x0000000000001234
           - AbbrCode:        0x00000000
             Values:
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(StringRef(yamldata));
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
-  VerifyError(DwarfContext,
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
+  VerifyError(*DwarfContext,
               "error: DW_FORM_ref_addr offset beyond .debug_info bounds:");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyInvalidRanges) {
   // Create a single compile unit with a DW_AT_ranges whose section offset
   // isn't valid.
   const char *yamldata = R"(
     debug_str:
debug_info:
           - AbbrCode:        0x00000001
             Values:
               - Value:           0x0000000000000001
               - Value:           0x0000000000001000
 
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(StringRef(yamldata));
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
-  VerifyError(DwarfContext,
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
+  VerifyError(*DwarfContext,
               "error: DW_AT_ranges offset is beyond .debug_ranges bounds:");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyInvalidStmtList) {
   // Create a single compile unit with a DW_AT_stmt_list whose section offset
   // isn't valid.
   const char *yamldata = R"(
     debug_str:
debug_info:
           - AbbrCode:        0x00000001
             Values:
               - Value:           0x0000000000000001
               - Value:           0x0000000000001000
 
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(StringRef(yamldata));
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
   VerifyError(
-      DwarfContext,
+      *DwarfContext,
       "error: DW_AT_stmt_list offset is beyond .debug_line bounds: 0x00001000");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyInvalidStrp) {
   // Create a single compile unit with a single function that has an invalid
   // DW_FORM_strp for the DW_AT_name.
   const char *yamldata = R"(
     debug_str:
debug_info:
         AddrSize:        8
         Entries:
           - AbbrCode:        0x00000001
             Values:
               - Value:           0x0000000000001234
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(StringRef(yamldata));
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
-  VerifyError(DwarfContext,
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
+  VerifyError(*DwarfContext,
               "error: DW_FORM_strp offset beyond .debug_str bounds:");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyInvalidRefAddrBetween) {
   // Create a single compile unit with a single function that has a DW_AT_type
   // with a valid .debug_info offset, but the offset is between two DIEs.
   const char *yamldata = R"(
     debug_str:
debug_info:
             Values:
               - Value:           0x000000000000000D
               - Value:           0x0000000000000011
           - AbbrCode:        0x00000000
             Values:
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(StringRef(yamldata));
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
   VerifyError(
-      DwarfContext,
+      *DwarfContext,
       "error: invalid DIE reference 0x00000011. Offset is in between DIEs:");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyInvalidLineSequence) {
   // Create a single compile unit whose line table has a sequence in it where
   // the address decreases.
   StringRef yamldata = R"(
     debug_str:
debug_line:
             Data:            18446744073709551600
           - Opcode:          DW_LNS_extended_op
             ExtLen:          1
             SubOpcode:       DW_LNE_end_sequence
             Data:            18446744073709551600
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(yamldata);
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
-  VerifyError(DwarfContext, "error: .debug_line[0x00000000] row[1] decreases "
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
+  VerifyError(*DwarfContext, "error: .debug_line[0x00000000] row[1] decreases "
                              "in address from previous row:");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyInvalidLineFileIndex) {
   // Create a single compile unit whose line table has a line table row with
   // an invalid file index.
   StringRef yamldata = R"(
     debug_str:
       - ''
debug_line:
             Data:            5
           - Opcode:          DW_LNS_extended_op
             ExtLen:          1
             SubOpcode:       DW_LNE_end_sequence
             Data:            5
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(yamldata);
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
-  VerifyError(DwarfContext, "error: .debug_line[0x00000000][1] has invalid "
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
+  VerifyError(*DwarfContext, "error: .debug_line[0x00000000][1] has invalid "
                              "file index 5 (valid values are [1,1]):");
 }
 
 TEST(DWARFDebugInfo, TestDwarfVerifyCUDontShareLineTable) {
   // Create a two compile units where both compile units share the same
   // DW_AT_stmt_list value and verify we report the error correctly.
   StringRef yamldata = R"(
     debug_str:
       - ''
debug_line:
             Data:            256
           - Opcode:          DW_LNS_extended_op
             ExtLen:          1
             SubOpcode:       DW_LNE_end_sequence
             Data:            256
   )";
   auto ErrOrSections = DWARFYAML::EmitDebugSections(yamldata);
   ASSERT_TRUE((bool)ErrOrSections);
-  DWARFContextInMemory DwarfContext(*ErrOrSections, 8);
-  VerifyError(DwarfContext, "error: two compile unit DIEs, 0x0000000b and "
-                            "0x0000001f, have the same DW_AT_stmt_list section "
-                            "offset:");
+  std::unique_ptr<DWARFContext> DwarfContext =
+      DWARFContext::create(*ErrOrSections, 8);
+  VerifyError(*DwarfContext,
+              "error: two compile unit DIEs, 0x0000000b and "
 }
 
 TEST(DWARFDebugInfo, TestErrorReportingPolicy) {
   Triple Triple("x86_64-pc-linux");
   if (!isConfigurationSupported(Triple))
       return;
 
   auto ExpectedDG = dwarfgen::Generator::create(Triple, 4 /*DwarfVersion*/);
TEST(DWARFDebugInfo, TestErrorReportingPolicy) {
   MemoryBufferRef FileBuffer(DG->generate(), "dwarf");
   auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
   EXPECT_TRUE((bool)Obj);
 
   // Case 1: error handler handles all errors. That allows
   // DWARFContextInMemory
   //         to parse whole file and find both two errors we know about.
   int Errors = 0;
-  DWARFContextInMemory Ctx1(*Obj.get(), nullptr, [&](Error E) {
+  std::unique_ptr<DWARFContext> Ctx1 =
+      DWARFContext::create(*Obj.get(), nullptr, [&](Error E) {
         ++Errors;
         consumeError(std::move(E));
         return ErrorPolicy::Continue;
       });
   EXPECT_TRUE(Errors == 2);
 
   // Case 2: error handler stops parsing of object after first error.
   Errors = 0;
-  DWARFContextInMemory Ctx2(*Obj.get(), nullptr, [&](Error E) {
+  std::unique_ptr<DWARFContext> Ctx2 =
+      DWARFContext::create(*Obj.get(), nullptr, [&](Error E) {
         ++Errors;
         consumeError(std::move(E));
         return ErrorPolicy::Halt;
       });
   EXPECT_TRUE(Errors == 1);
 }
 
 } // end anonymous namespace