Make a DWARFDIE class that can help avoid using the wrong DWARFUnit when extracting attributes

[clayborg]

Summary

Many places pass around a DWARFDebugInfoEntryMinimal and a DWARFUnit. It is easy to get things wrong by using the wrong DWARFUnit with a DWARFDebugInfoEntryMinimal. This patch creates a DWARFDie class that contains the DWARFUnit and DWARFDebugInfoEntryMinimal objects so that they can't get out of sync. All attribute extraction has been moved out of DWARFDebugInfoEntryMinimal and into DWARFDie. DWARFDebugInfoEntryMinimal was also renamed to DWARFDebugInfoEntry.

DWARFDie objects are temporary objects that are used by clients and contain 2 pointers that you always need to have anyway. Keeping them grouped will avoid errors and simplify many of the attribute extracting APIs by not having to pass in a DWARFUnit.

[aprantl]

include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h

29

Is this comment still accurate?

include/llvm/DebugInfo/DWARF/DWARFDie.h

61

Optional<uint32_t> ?
Optional<DwarfOffset>, to allow 64-bit?

73

Is it reasonable to call this if Die is null, or should this be an assertion?

77

operator bool() const?
Oh, or does this mean the NULL DIE that is at the end of each group?

91

Perhaps Optional instead of default-construction?

107

attributes

125

Just a general remark: I wonder if these interfaces wouldn't be better if they returned Optionals instead of taking fail values, but I haven't looked at the call sites yet.

295

Typically we write these functions as taking a SmallVectorImpl&, but I wonder if this isn't an artifact from before we could use auto in the code base.

lib/DebugInfo/DWARF/DWARFContext.cpp

160

these changes could be separate NFC commits. No need to pre-commit-review them.

[clayborg]

Commented a bit with fixes coming soon.

include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h

29

Yes it is still accurate.

include/llvm/DebugInfo/DWARF/DWARFDie.h

61

These are wrapping the APIs that used to be in DWARFDebugInfoEntryMinimal for now. I will add Optional support to all values in a follow up patch.

71

Many APIs can give you back an DWARFDie object that don't contain a DWARFUnit or DWARFDie so it does make sense to answer as correctly as possible

77

This means valid but NULL Die. I should actually change this do be:

return Die != nullptr && getAbbreviationDeclarationPtr() == nullptr;

Because isNULL should only be true if we have a valid DWARFDebugInfoEntry, yet it has an abbrev code of zero

91

Good idea.I'll do that in a follow up change once this is in.

124–125

Let me do this in a follow up change otherwise this will introduce a ton of churn in this change. Is that ok?

lib/DebugInfo/DWARF/DWARFContext.cpp

159–160

It isn't a pointer anymore, it is an object. So this does go along with this change. It is invoking the operator bool on DWARFDie.

[clayborg]

Fixed Adrian's issues.

[clayborg]

Marked things as done.

[clayborg]

Fixed some issues that David Blaikie mentioned on the mailing list: add asserts to functions in DWARFDie that return things like the getOffset(), getTag(), hasChildren() and a few others. Users should check a DWARFDie for validity before using it.

[aprantl]

This is looking good now. Looking forward to the follow-up commits that will clean up the API and introduce Optionals, etc.

include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h

 
 class DWARFDebugAranges;
 class DWARFCompileUnit;
 class DWARFUnit;
 class DWARFContext;
 class DWARFFormValue;
 struct DWARFDebugInfoEntryInlinedChain;
 
-/// DWARFDebugInfoEntryMinimal - A DIE with only the minimum required data.
-class DWARFDebugInfoEntryMinimal {
+/// DWARFDebugInfoEntry - A DIE with only the minimum required data.
+class DWARFDebugInfoEntry {
   /// Offset within the .debug_info of the start of this entry.
   uint32_t Offset;
 
   /// How many to add to "this" to get the sibling.
   uint32_t SiblingIdx;
 
   const DWARFAbbreviationDeclaration *AbbrevDecl;
 public:
-  DWARFDebugInfoEntryMinimal()
+  DWARFDebugInfoEntry()
     : Offset(0), SiblingIdx(0), AbbrevDecl(nullptr) {}
 
-  void dump(raw_ostream &OS, DWARFUnit *u, unsigned recurseDepth,
-            unsigned indent = 0) const;
-  void dumpAttribute(raw_ostream &OS, DWARFUnit *u, uint32_t *offset_ptr,
-                     dwarf::Attribute attr, dwarf::Form form, 
-                     unsigned indent = 0) const;
-
   /// Extracts a debug info entry, which is a child of a given unit,
   /// starting at a given offset. If DIE can't be extracted, returns false and
   /// doesn't change OffsetPtr.
   bool extractFast(const DWARFUnit &U, uint32_t *OffsetPtr);
   /// High performance extraction should use this call.
   bool extractFast(const DWARFUnit &U, uint32_t *OffsetPtr,
                    const DataExtractor &DebugInfoData, uint32_t UEndOffset);
 
-  dwarf::Tag getTag() const {
-    return AbbrevDecl ? AbbrevDecl->getTag() : dwarf::DW_TAG_null;
-  }
-
-  bool isNULL() const { return AbbrevDecl == nullptr; }
-
-  /// Returns true if DIE represents a subprogram (not inlined).
-  bool isSubprogramDIE() const;
-  /// Returns true if DIE represents a subprogram or an inlined
-  /// subroutine.
-  bool isSubroutineDIE() const;
-
   uint32_t getOffset() const { return Offset; }
-  bool hasChildren() const { return !isNULL() && AbbrevDecl->hasChildren(); }
+  bool hasChildren() const { return AbbrevDecl && AbbrevDecl->hasChildren(); }
 
   // We know we are kept in a vector of contiguous entries, so we know
   // our sibling will be some index after "this".
-  const DWARFDebugInfoEntryMinimal *getSibling() const {
+  const DWARFDebugInfoEntry *getSibling() const {
     return SiblingIdx > 0 ? this + SiblingIdx : nullptr;
   }
 
   // We know we are kept in a vector of contiguous entries, so we know
   // we don't need to store our child pointer, if we have a child it will
   // be the next entry in the list...
-  const DWARFDebugInfoEntryMinimal *getFirstChild() const {
+  const DWARFDebugInfoEntry *getFirstChild() const {
     return hasChildren() ? this + 1 : nullptr;
   }
 
-  void setSibling(const DWARFDebugInfoEntryMinimal *Sibling) {
+  void setSibling(const DWARFDebugInfoEntry *Sibling) {
     if (Sibling) {
       // We know we are kept in a vector of contiguous entries, so we know
       // our sibling will be some index after "this".
       SiblingIdx = Sibling - this;
     } else
       SiblingIdx = 0;
   }
 
   const DWARFAbbreviationDeclaration *getAbbreviationDeclarationPtr() const {
     return AbbrevDecl;
   }
-
-  bool getAttributeValue(const DWARFUnit *U, dwarf::Attribute Attr,
-                         DWARFFormValue &FormValue) const;
-
-  const char *getAttributeValueAsString(const DWARFUnit *U, 
-                                        dwarf::Attribute Attr,
-                                        const char *FailValue) const;
-
-  uint64_t getAttributeValueAsAddress(const DWARFUnit *U, 
-                                      dwarf::Attribute Attr,
-                                      uint64_t FailValue) const;
-
-  int64_t getAttributeValueAsSignedConstant(const DWARFUnit *U,
-                                            dwarf::Attribute Attr,
-                                            int64_t FailValue) const;
-
-  uint64_t getAttributeValueAsUnsignedConstant(const DWARFUnit *U,
-                                               dwarf::Attribute Attr,
-                                               uint64_t FailValue) const;
-
-  uint64_t getAttributeValueAsReference(const DWARFUnit *U, 
-                                        dwarf::Attribute Attr,
-                                        uint64_t FailValue) const;
-
-  uint64_t getAttributeValueAsSectionOffset(const DWARFUnit *U,
-                                            dwarf::Attribute Attr,
-                                            uint64_t FailValue) const;
-
-  uint64_t getRangesBaseAttribute(const DWARFUnit *U, uint64_t FailValue) const;
-
-  /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU.
-  /// Returns true if both attributes are present.
-  bool getLowAndHighPC(const DWARFUnit *U, uint64_t &LowPC,
-                       uint64_t &HighPC) const;
-
-  DWARFAddressRangesVector getAddressRanges(const DWARFUnit *U) const;
-
-  void collectChildrenAddressRanges(const DWARFUnit *U,
-                                    DWARFAddressRangesVector &Ranges) const;
-
-  bool addressRangeContainsAddress(const DWARFUnit *U,
-                                   const uint64_t Address) const;
-
-  /// If a DIE represents a subprogram (or inlined subroutine),
-  /// returns its mangled name (or short name, if mangled is missing).
-  /// This name may be fetched from specification or abstract origin
-  /// for this subprogram. Returns null if no name is found.
-  const char *getSubroutineName(const DWARFUnit *U, DINameKind Kind) const;
-
-  /// Return the DIE name resolving DW_AT_sepcification or
-  /// DW_AT_abstract_origin references if necessary.
-  /// Returns null if no name is found.
-  const char *getName(const DWARFUnit *U, DINameKind Kind) const;
-
-  /// Retrieves values of DW_AT_call_file, DW_AT_call_line and
-  /// DW_AT_call_column from DIE (or zeroes if they are missing).
-  void getCallerFrame(const DWARFUnit *U, uint32_t &CallFile,
-                      uint32_t &CallLine, uint32_t &CallColumn) const;
-
-  /// Get inlined chain for a given address, rooted at the current DIE.
-  /// Returns empty chain if address is not contained in address range
-  /// of current DIE.
-  DWARFDebugInfoEntryInlinedChain
-  getInlinedChainForAddress(const DWARFUnit *U, const uint64_t Address) const;
-};
-
-/// DWARFDebugInfoEntryInlinedChain - represents a chain of inlined_subroutine
-/// DIEs, (possibly ending with subprogram DIE), all of which are contained
-/// in some concrete inlined instance tree. Address range for each DIE
-/// (except the last DIE) in this chain is contained in address
-/// range for next DIE in the chain.
-struct DWARFDebugInfoEntryInlinedChain {
-  DWARFDebugInfoEntryInlinedChain() : U(nullptr) {}
-  SmallVector<DWARFDebugInfoEntryMinimal, 4> DIEs;
-  const DWARFUnit *U;
 };
 
 }
 
 #endif

include/llvm/DebugInfo/DWARF/DWARFDie.h

+//===-- DWARFDie.h --------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDIE_H
+#define LLVM_LIB_DEBUGINFO_DWARFDIE_H
+
+#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
+
+namespace llvm {
+    
+class DWARFUnit;
+class DWARFDebugInfoEntry;
+class raw_ostream;
+  
+//===----------------------------------------------------------------------===//
+/// Utility class that carries the DWARF compile/type unit and the debug info
+/// entry in an object.
+///
+/// When accessing information from a debug info entry we always need to DWARF
+/// compile/type unit in order to extract the info correctly as some information
+/// is relative to the compile/type unit. Prior to this class the DWARFUnit and
+/// the DWARFDebugInfoEntry was passed around separately and there was the
+/// possibility for error if the wrong DWARFUnit was used to extract a unit
+/// relative offset. This class helps to ensure that this doesn't happen and
+/// also simplifies the attribute extraction calls by not having to specify the
+/// DWARFUnit for each call.
+class DWARFDie {
+  DWARFUnit *U;
+  const DWARFDebugInfoEntry *Die;
+public:
+  DWARFDie() : U(nullptr), Die(nullptr) {}
+  DWARFDie(DWARFUnit *Unit, const DWARFDebugInfoEntry * D) : U(Unit), Die(D) {}
+  
+  bool isValid() const { return U && Die; }
+  explicit operator bool() const { return isValid(); }
+  const DWARFDebugInfoEntry *getDebugInfoEntry() const { return Die; }
+  DWARFUnit *getDwarfUnit() const { return U; }
+
+
+  /// Get the abbreviation declaration for this DIE.
+  ///
+  /// \returns the abbreviation declaration or NULL for null tags.
+  const DWARFAbbreviationDeclaration *getAbbreviationDeclarationPtr() const {
+    if (Die)
+      return Die->getAbbreviationDeclarationPtr();
+    return nullptr;
+  }
+
+  /// Get the absolute offset into the debug info or types section.
+  ///
+  /// \returns the DIE offset or -1U if invalid.
+  uint32_t getOffset() const {
+    if (Die)
+      return Die->getOffset();
+    return -1U;
+  }
+  
+  dwarf::Tag getTag() const {
+    auto AbbrevDecl = getAbbreviationDeclarationPtr();
+    if (AbbrevDecl)
+      return AbbrevDecl->getTag();
+    return dwarf::DW_TAG_null;
+  }
+
+  bool hasChildren() const {
+    if (Die)
+      return Die->hasChildren();
+    return false;
+  }
+  
+  bool isNULL() const {
+    return getAbbreviationDeclarationPtr() == nullptr;
+  }
+  /// Returns true if DIE represents a subprogram (not inlined).
+  bool isSubprogramDIE() const;
+
+  /// Returns true if DIE represents a subprogram or an inlined subroutine.
+  bool isSubroutineDIE() const;
+
+
+  /// Get the silbing of this DIE object.
+  ///
+  /// \returns a valid DWARFDie instance if this object has a sibling or an
+  /// invalid DWARFDie instance if it doesn't.
+  DWARFDie getSibling() const {
+    if (isValid())
+      return DWARFDie(U, Die->getSibling());
+    return DWARFDie();
+  }
+  
+  /// Get the first child of this DIE object.
+  ///
+  /// \returns a valid DWARFDie instance if this object has children or an
+  /// invalid DWARFDie instance if it doesn't.
+  DWARFDie getFirstChild() const {
+    if (isValid())
+      return DWARFDie(U, Die->getFirstChild());
+    return DWARFDie();
+  }
+  
+  /// Dump the DIE and all of its attribytes to the supplied stream.
+  ///
+  /// \param OS the stream to use for output.
+  /// \param recurseDepth the depth to recurse to when dumping this DIE and its
+  /// children.
+  /// \param indent the number of characters to indent each line that is output.
+  void dump(raw_ostream &OS, unsigned recurseDepth, unsigned indent = 0) const;
+  
+  /// Extract the specified attribute from this DIE.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \param FormValue contains the attribute value if true is returned.
+  /// \returns true if the attribute was extracted from this DIE.
+  bool getAttributeValue(dwarf::Attribute Attr,
+                         DWARFFormValue &FormValue) const;
+  
+  /// Extract the specified attribute from this DIE as a C string.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \param FailValue the value to return if this DIE doesn't have this
+  /// attribute.
+  /// \returns the NULL terminated C string value owned by the DWARF section
+  /// that contains the string or FailValue if the attribute doesn't exist or
+  /// if the attribute's form isn't a form that describes an string.
+  const char *getAttributeValueAsString(dwarf::Attribute Attr,
+                                        const char *FailValue) const;
+  
+  /// Extract the specified attribute from this DIE as an address.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \param FailValue the value to return if this DIE doesn't have this
+  /// attribute.
+  /// \returns the address value of the attribute or FailValue if the
+  /// attribute doesn't exist or if the attribute's form isn't a form that
+  /// describes an address.
+  uint64_t getAttributeValueAsAddress(dwarf::Attribute Attr,
+                                      uint64_t FailValue) const;
+  
+  /// Extract the specified attribute from this DIE as a signed integer.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \param FailValue the value to return if this DIE doesn't have this
+  /// attribute.
+  /// \returns the signed integer constant value of the attribute or FailValue
+  /// if the attribute doesn't exist or if the attribute's form isn't a form
+  /// that describes a signed integer.
+  int64_t getAttributeValueAsSignedConstant(dwarf::Attribute Attr,
+                                            int64_t FailValue) const;
+  
+  /// Extract the specified attribute from this DIE as an unsigned integer.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \param FailValue the value to return if this DIE doesn't have this
+  /// attribute.
+  /// \returns the unsigned integer constant value of the attribute or FailValue
+  /// if the attribute doesn't exist or if the attribute's form isn't a form
+  /// that describes an unsigned integer.
+  uint64_t getAttributeValueAsUnsignedConstant(dwarf::Attribute Attr,
+                                               uint64_t FailValue) const;
+  
+  /// Extract the specified attribute from this DIE as absolute DIE Offset.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \param FailValue the value to return if this DIE doesn't have this
+  /// attribute.
+  /// \returns the unsigned integer constant value of the attribute or FailValue
+  /// if the attribute doesn't exist or if the attribute's form isn't a form
+  /// that describes a reference.
+  uint64_t getAttributeValueAsReference(dwarf::Attribute Attr,
+                                        uint64_t FailValue) const;
+  
+  /// Extract the specified attribute from this DIE as absolute section offset.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \param FailValue the value to return if this DIE doesn't have this
+  /// attribute.
+  /// \returns the unsigned integer constant value of the attribute or FailValue
+  /// if the attribute doesn't exist or if the attribute's form isn't a form
+  /// that describes a section offset.
+  uint64_t getAttributeValueAsSectionOffset(dwarf::Attribute Attr,
+                                            uint64_t FailValue) const;
+  
+  /// Extract the specified attribute from this DIE as the referenced DIE.
+  ///
+  /// Regardless of the reference type, return the correct DWARFDie instance if
+  /// the attribute exists. The returned DWARFDie object might be from another
+  /// DWARFUnit, but that is all encapsulated in the new DWARFDie object.
+  ///
+  /// Extract an attribute value from this DIE only. This call doesn't look
+  /// for the attribute value in any DW_AT_specification or
+  /// DW_AT_abstract_origin referenced DIEs.
+  ///
+  /// \param Attr the attribute to extract.
+  /// \returns a valid DWARFDie instance if the attribute exists, or an invalid
+  /// DWARFDie object if it doesn't.
+  DWARFDie getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const;
+
+  /// Extract the range base attribute from this DIE as absolute section offset.
+  ///
+  /// This is a utility function that checks for either the DW_AT_rnglists_base
+  /// or DW_AT_GNU_ranges_base attribute.
+  ///
+  /// \returns the absolute section offset value of the attribute or FailValue
+  /// if the attribute doesn't exist.
+  uint64_t getRangesBaseAttribute(uint64_t FailValue) const;
+  
+  /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU.
+  /// Returns true if both attributes are present.
+  bool getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC) const;
+  
+  /// Get the address ranges for this DIE.
+  ///
+  /// Get the hi/low PC range if both attributes are available or exrtracts the
+  /// non-contiguous address ranges from the DW_AT_ranges attribute.
+  ///
+  /// Extracts the range information from this DIE only. This call doesn't look
+  /// for the range in any DW_AT_specification or DW_AT_abstract_origin DIEs.
+  ///
+  /// \returns a address range vector that might be empty if no address range
+  /// information is available.
+  DWARFAddressRangesVector getAddressRanges() const;
+  
+  /// Get all address ranges for any DW_TAG_subprogram DIEs in this DIE or any
+  /// of its children.
+  ///
+  /// Get the hi/low PC range if both attributes are available or exrtracts the
+  /// non-contiguous address ranges from the DW_AT_ranges attribute for this DIE
+  /// and all children.
+  ///
+  /// \param Ranges the addres range vector to fill in.
+  void collectChildrenAddressRanges(DWARFAddressRangesVector &Ranges) const;
+  
+  bool addressRangeContainsAddress(const uint64_t Address) const;
+  
+  /// If a DIE represents a subprogram (or inlined subroutine), returns its
+  /// mangled name (or short name, if mangled is missing). This name may be
+  /// fetched from specification or abstract origin for this subprogram.
+  /// Returns null if no name is found.
+  const char *getSubroutineName(DINameKind Kind) const;
+  
+  /// Return the DIE name resolving DW_AT_sepcification or DW_AT_abstract_origin
+  /// references if necessary. Returns null if no name is found.
+  const char *getName(DINameKind Kind) const;
+  
+  /// Retrieves values of DW_AT_call_file, DW_AT_call_line and DW_AT_call_column
+  /// from DIE (or zeroes if they are missing). This function looks for
+  /// DW_AT_call attributes in this DIE only, it will not resolve the attribute
+  /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs.
+  /// \param CallFile filled in with non-zero if successful, zero if there is no
+  /// DW_AT_call_file attribute in this DIE.
+  /// \param CallLine filled in with non-zero if successful, zero if there is no
+  /// DW_AT_call_line attribute in this DIE.
+  /// \param CallColumn filled in with non-zero if successful, zero if there is
+  /// no DW_AT_call_column attribute in this DIE.
+  void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
+                      uint32_t &CallColumn) const;
+  
+  /// Get inlined chain for a given address, rooted at the current DIE.
+  /// Returns empty chain if address is not contained in address range
+  /// of current DIE.
+  SmallVector<DWARFDie, 4>
+  getInlinedChainForAddress(const uint64_t Address) const;
+
+};
+
+
+} // end namespace llvm
+
+#endif  // LLVM_LIB_DEBUGINFO_DWARFDIE_H

include/llvm/DebugInfo/DWARF/DWARFUnit.h

 //===-- DWARFUnit.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_LIB_DEBUGINFO_DWARFUNIT_H
 #define LLVM_LIB_DEBUGINFO_DWARFUNIT_H
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
+#include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
 #include <vector>
 
 namespace llvm {
 
 namespace object {
class DWARFUnit {
 
   uint32_t Offset;
   uint32_t Length;
   uint16_t Version;
   const DWARFAbbreviationDeclarationSet *Abbrevs;
   uint8_t AddrSize;
   uint64_t BaseAddr;
   // The compile unit debug information entry items.
-  std::vector<DWARFDebugInfoEntryMinimal> DieArray;
+  std::vector<DWARFDebugInfoEntry> DieArray;
 
   class DWOHolder {
     object::OwningBinary<object::ObjectFile> DWOFile;
     std::unique_ptr<DWARFContext> DWOContext;
     DWARFUnit *DWOU;
   public:
     DWOHolder(StringRef DWOPath);
     DWARFUnit *getUnit() const { return DWOU; }
uint8_t getDwarfOffsetByteSize() const {
     return 4;
   }
   uint64_t getBaseAddress() const { return BaseAddr; }
 
   void setBaseAddress(uint64_t base_addr) {
     BaseAddr = base_addr;
   }
 
-  const DWARFDebugInfoEntryMinimal *getUnitDIE(bool ExtractUnitDIEOnly = true) {
+  DWARFDie getUnitDIE(bool ExtractUnitDIEOnly = true) {
     extractDIEsIfNeeded(ExtractUnitDIEOnly);
-    return DieArray.empty() ? nullptr : &DieArray[0];
+    if (DieArray.empty())
+      return DWARFDie();
+    return DWARFDie(this, &DieArray[0]);
   }
 
   const char *getCompilationDir();
   uint64_t getDWOId();
 
   void collectAddressRanges(DWARFAddressRangesVector &CURanges);
 
   /// getInlinedChainForAddress - fetches inlined chain for a given address.
   /// Returns empty chain if there is no subprogram containing address. The
   /// chain is valid as long as parsed compile unit DIEs are not cleared.
-  DWARFDebugInfoEntryInlinedChain getInlinedChainForAddress(uint64_t Address);
+  SmallVector<DWARFDie, 4> getInlinedChainForAddress(uint64_t Address);
 
   /// getUnitSection - Return the DWARFUnitSection containing this unit.
   const DWARFUnitSectionBase &getUnitSection() const { return UnitSection; }
 
   /// \brief Returns the number of DIEs in the unit. Parses the unit
   /// if necessary.
   unsigned getNumDIEs() {
     extractDIEsIfNeeded(false);
     return DieArray.size();
   }
 
   /// \brief Return the index of a DIE inside the unit's DIE vector.
   ///
   /// It is illegal to call this method with a DIE that hasn't be
   /// created by this unit. In other word, it's illegal to call this
   /// method on a DIE that isn't accessible by following
   /// children/sibling links starting from this unit's getUnitDIE().
-  uint32_t getDIEIndex(const DWARFDebugInfoEntryMinimal *DIE) {
+  uint32_t getDIEIndex(const DWARFDie &D) {
+    auto DIE = D.getDebugInfoEntry();
     assert(!DieArray.empty() && DIE >= &DieArray[0] &&
            DIE < &DieArray[0] + DieArray.size());
     return DIE - &DieArray[0];
   }
 
   /// \brief Return the DIE object at the given index.
-  const DWARFDebugInfoEntryMinimal *getDIEAtIndex(unsigned Index) const {
-    assert(Index < DieArray.size());
-    return &DieArray[Index];
+  DWARFDie getDIEAtIndex(unsigned Index) {
+    if (Index < DieArray.size())
+      return DWARFDie(this, &DieArray[Index]);
+    return DWARFDie();
   }
 
   /// \brief Return the DIE object for a given offset inside the
   /// unit's DIE vector.
   ///
   /// The unit needs to have its DIEs extracted for this method to work.
-  const DWARFDebugInfoEntryMinimal *getDIEForOffset(uint32_t Offset) {
+  DWARFDie getDIEForOffset(uint32_t Offset) {
     extractDIEsIfNeeded(false);
     assert(!DieArray.empty());
     auto it = std::lower_bound(
         DieArray.begin(), DieArray.end(), Offset,
-        [](const DWARFDebugInfoEntryMinimal &LHS, uint32_t Offset) {
+        [](const DWARFDebugInfoEntry &LHS, uint32_t Offset) {
           return LHS.getOffset() < Offset;
         });
-    return it == DieArray.end() ? nullptr : &*it;
+    if (it == DieArray.end())
+      return DWARFDie();
+    return DWARFDie(this, &*it);
   }
 
   uint32_t getLineTableOffset() const {
     if (IndexEntry)
       if (const auto *Contrib = IndexEntry->getOffset(DW_SECT_LINE))
         return Contrib->Offset;
     return 0;
   }
 
 private:
   /// Size in bytes of the .debug_info data associated with this compile unit.
   size_t getDebugInfoSize() const { return Length + 4 - getHeaderSize(); }
 
   /// extractDIEsIfNeeded - Parses a compile unit and indexes its DIEs if it
   /// hasn't already been done. Returns the number of DIEs parsed at this call.
   size_t extractDIEsIfNeeded(bool CUDieOnly);
   /// extractDIEsToVector - Appends all parsed DIEs to a vector.
   void extractDIEsToVector(bool AppendCUDie, bool AppendNonCUDIEs,
-                           std::vector<DWARFDebugInfoEntryMinimal> &DIEs) const;
+                           std::vector<DWARFDebugInfoEntry> &DIEs) const;
   /// setDIERelations - We read in all of the DIE entries into our flat list
   /// of DIE entries and now we need to go back through all of them and set the
   /// parent, sibling and child pointers for quick DIE navigation.
   void setDIERelations();
   /// clearDIEs - Clear parsed DIEs to keep memory usage low.
   void clearDIEs(bool KeepCUDie);
 
   /// parseDWO - Parses .dwo file for current compile unit. Returns true if
   /// it was actually constructed.
   bool parseDWO();
 
   /// getSubprogramForAddress - Returns subprogram DIE with address range
   /// encompassing the provided address. The pointer is alive as long as parsed
   /// compile unit DIEs are not cleared.
-  const DWARFDebugInfoEntryMinimal *getSubprogramForAddress(uint64_t Address);
+  DWARFDie getSubprogramForAddress(uint64_t Address);
 };
 
 }
 
 #endif

lib/DebugInfo/DWARF/CMakeLists.txt

 add_llvm_library(LLVMDebugInfoDWARF
   DWARFAbbreviationDeclaration.cpp
   DWARFAcceleratorTable.cpp
   DWARFCompileUnit.cpp
   DWARFContext.cpp
   DWARFDebugAbbrev.cpp
   DWARFDebugArangeSet.cpp
   DWARFDebugAranges.cpp
   DWARFDebugFrame.cpp
   DWARFDebugInfoEntry.cpp
   DWARFDebugLine.cpp
   DWARFDebugLoc.cpp
   DWARFDebugMacro.cpp
   DWARFDebugRangeList.cpp
+  DWARFDie.cpp
   DWARFFormValue.cpp
   DWARFGdbIndex.cpp
   DWARFTypeUnit.cpp
   DWARFUnitIndex.cpp
   DWARFUnit.cpp
   SyntaxHighlighting.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/DebugInfo/DWARF
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/DebugInfo
   )

lib/DebugInfo/DWARF/DWARFCompileUnit.cpp

 //===-- DWARFCompileUnit.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/DWARFCompileUnit.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
-#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
+#include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
 void DWARFCompileUnit::dump(raw_ostream &OS) {
   OS << format("0x%08x", getOffset()) << ": Compile Unit:"
      << " length = " << format("0x%08x", getLength())
      << " version = " << format("0x%04x", getVersion())
      << " abbr_offset = " << format("0x%04x", getAbbreviations()->getOffset())
      << " addr_size = " << format("0x%02x", getAddressByteSize())
      << " (next unit at " << format("0x%08x", getNextUnitOffset())
      << ")\n";
 
-  if (const DWARFDebugInfoEntryMinimal *CU = getUnitDIE(false))
-    CU->dump(OS, this, -1U);
+  if (DWARFDie CUDie = getUnitDIE(false))
+    CUDie.dump(OS, -1U);
   else
     OS << "<compile unit can't be parsed!>\n\n";
 }
 
 // VTable anchor.
 DWARFCompileUnit::~DWARFCompileUnit() = default;

lib/DebugInfo/DWARF/DWARFContext.cpp

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();
-      const auto *CUDIE = CU->getUnitDIE();
-      if (CUDIE == nullptr)
+      auto CUDIE = CU->getUnitDIE();
+      if (!CUDIE)
         continue;
-      unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
-          CU.get(), DW_AT_stmt_list, -1U);
+      unsigned stmtOffset = CUDIE.getAttributeValueAsSectionOffset(
+          DW_AT_stmt_list, -1U);
       if (stmtOffset != -1U) {
         DataExtractor lineData(getLineSection().Data, isLittleEndian(),
                                savedAddressByteSize);
         DWARFDebugLine::LineTable LineTable;
         LineTable.parse(lineData, &getLineSection().Relocs, &stmtOffset);
         LineTable.dump(OS);
       }
     }
const DWARFDebugMacro *DWARFContext::getDebugMacro() {
   return Macro.get();
 }
 
 const DWARFLineTable *
 DWARFContext::getLineTableForUnit(DWARFUnit *U) {
   if (!Line)
     Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
 
-  const auto *UnitDIE = U->getUnitDIE();
-  if (UnitDIE == nullptr)
+  auto UnitDIE = U->getUnitDIE();
+  if (!UnitDIE)
     return nullptr;
 
   unsigned stmtOffset =
-      UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U);
+      UnitDIE.getAttributeValueAsSectionOffset(DW_AT_stmt_list, -1U);
   if (stmtOffset == -1U)
     return nullptr; // No line table for this compile unit.
 
   stmtOffset += U->getLineTableOffset();
   // See if the line table is cached.
   if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
     return lt;
 

 static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
                                       FunctionNameKind Kind,
                                       std::string &FunctionName) {
   if (Kind == FunctionNameKind::None)
     return false;
   // The address may correspond to instruction in some inlined function,
   // so we have to build the chain of inlined functions and take the
   // name of the topmost function in it.
-  const DWARFDebugInfoEntryInlinedChain &InlinedChain =
-      CU->getInlinedChainForAddress(Address);
-  if (InlinedChain.DIEs.size() == 0)
+  auto InlinedChain = CU->getInlinedChainForAddress(Address);
+  if (InlinedChain.size() == 0)
     return false;
-  const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
-  if (const char *Name =
-          TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) {
+  if (const char *Name = InlinedChain[0].getSubroutineName(Kind)) {
     FunctionName = Name;
     return true;
   }
   return false;
 }
 
 DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
                                                DILineInfoSpecifier Spec) {
DWARFContext::getInliningInfoForAddress(uint64_t Address,
                                         DILineInfoSpecifier Spec) {
   DIInliningInfo InliningInfo;
 
   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
   if (!CU)
     return InliningInfo;
 
   const DWARFLineTable *LineTable = nullptr;
-  const DWARFDebugInfoEntryInlinedChain &InlinedChain =
-      CU->getInlinedChainForAddress(Address);
-  if (InlinedChain.DIEs.size() == 0) {
+  auto InlinedChain = CU->getInlinedChainForAddress(Address);
+  if (InlinedChain.size() == 0) {
     // If there is no DIE for address (e.g. it is in unavailable .dwo file),
     // try to at least get file/line info from symbol table.
     if (Spec.FLIKind != FileLineInfoKind::None) {
       DILineInfo Frame;
       LineTable = getLineTableForUnit(CU);
       if (LineTable &&
           LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
                                                Spec.FLIKind, Frame))
         InliningInfo.addFrame(Frame);
     }
     return InliningInfo;
   }
 
   uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
-  for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
-    const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
+  for (uint32_t i = 0, n = InlinedChain.size(); i != n; i++) {
+    DWARFDie &FunctionDIE = InlinedChain[i];
     DILineInfo Frame;
     // Get function name if necessary.
-    if (const char *Name =
-            FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind))
+    if (const char *Name = FunctionDIE.getSubroutineName(Spec.FNKind))
       Frame.FunctionName = Name;
     if (Spec.FLIKind != FileLineInfoKind::None) {
       if (i == 0) {
         // For the topmost frame, initialize the line table of this
         // compile unit and fetch file/line info from it.
         LineTable = getLineTableForUnit(CU);
         // For the topmost routine, get file/line info from line table.
         if (LineTable)
           LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
                                                Spec.FLIKind, Frame);
       } else {
         // Otherwise, use call file, call line and call column from
         // previous DIE in inlined chain.
         if (LineTable)
           LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
                                         Spec.FLIKind, Frame.FileName);
         Frame.Line = CallLine;
         Frame.Column = CallColumn;
       }
       // Get call file/line/column of a current DIE.
       if (i + 1 < n) {
-        FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
-                                   CallColumn);
+        FunctionDIE.getCallerFrame(CallFile, CallLine, CallColumn);
       }
     }
     InliningInfo.addFrame(Frame);
   }
   return InliningInfo;
 }
 
 static bool consumeCompressedGnuHeader(StringRef &data,

lib/DebugInfo/DWARF/DWARFDebugInfoEntry.cpp

 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 using namespace dwarf;
 using namespace syntax;
 
-// Small helper to extract a DIE pointed by a reference
-// attribute. It looks up the Unit containing the DIE and calls
-// DIE.extractFast with the right unit. Returns new unit on success,
-// nullptr otherwise.
-static const DWARFUnit *findUnitAndExtractFast(DWARFDebugInfoEntryMinimal &DIE,
-                                               const DWARFUnit *Unit,
-                                               uint32_t *Offset) {
-  Unit = Unit->getUnitSection().getUnitForOffset(*Offset);
-  return (Unit && DIE.extractFast(*Unit, Offset)) ? Unit : nullptr;
-}
-
-void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS, DWARFUnit *u,
-                                      unsigned recurseDepth,
-                                      unsigned indent) const {
-  DataExtractor debug_info_data = u->getDebugInfoExtractor();
-  uint32_t offset = Offset;
-
-  if (debug_info_data.isValidOffset(offset)) {
-    uint32_t abbrCode = debug_info_data.getULEB128(&offset);
-    WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
-
-    if (abbrCode) {
-      if (AbbrevDecl) {
-        auto tagString = TagString(getTag());
-        if (!tagString.empty())
-          WithColor(OS, syntax::Tag).get().indent(indent) << tagString;
-        else
-          WithColor(OS, syntax::Tag).get().indent(indent)
-              << format("DW_TAG_Unknown_%x", getTag());
-
-        OS << format(" [%u] %c\n", abbrCode,
-                     AbbrevDecl->hasChildren() ? '*' : ' ');
-
-        // Dump all data in the DIE for the attributes.
-        for (const auto &AttrSpec : AbbrevDecl->attributes()) {
-          dumpAttribute(OS, u, &offset, AttrSpec.Attr, AttrSpec.Form, indent);
-        }
-
-        const DWARFDebugInfoEntryMinimal *child = getFirstChild();
-        if (recurseDepth > 0 && child) {
-          while (child) {
-            child->dump(OS, u, recurseDepth-1, indent+2);
-            child = child->getSibling();
-          }
-        }
-      } else {
-        OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
-           << abbrCode << '\n';
-      }
-    } else {
-      OS.indent(indent) << "NULL\n";
-    }
-  }
-}
-
-static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
-  OS << " (";
-  do {
-    uint64_t Shift = countTrailingZeros(Val);
-    assert(Shift < 64 && "undefined behavior");
-    uint64_t Bit = 1ULL << Shift;
-    auto PropName = ApplePropertyString(Bit);
-    if (!PropName.empty())
-      OS << PropName;
-    else
-      OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
-    if (!(Val ^= Bit))
-      break;
-    OS << ", ";
-  } while (true);
-  OS << ")";
-}
-
-static void dumpRanges(raw_ostream &OS, const DWARFAddressRangesVector& Ranges,
-                       unsigned AddressSize, unsigned Indent) {
-  if (Ranges.empty())
-    return;
-
-  for (const auto &Range: Ranges) {
-    OS << '\n';
-    OS.indent(Indent);
-    OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")",
-                 AddressSize*2, Range.first,
-                 AddressSize*2, Range.second);
-  }
-}
-
-void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
-                                               DWARFUnit *u,
-                                               uint32_t *offset_ptr,
-                                               dwarf::Attribute attr, 
-                                               dwarf::Form form,
-                                               unsigned indent) const {
-  const char BaseIndent[] = "            ";
-  OS << BaseIndent;
-  OS.indent(indent+2);
-  auto attrString = AttributeString(attr);
-  if (!attrString.empty())
-    WithColor(OS, syntax::Attribute) << attrString;
-  else
-    WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", attr);
-
-  auto formString = FormEncodingString(form);
-  if (!formString.empty())
-    OS << " [" << formString << ']';
-  else
-    OS << format(" [DW_FORM_Unknown_%x]", form);
-
-  DWARFFormValue formValue(form);
-
-  if (!formValue.extractValue(u->getDebugInfoExtractor(), offset_ptr, u))
-    return;
-
-  OS << "\t(";
-
-  StringRef Name;
-  std::string File;
-  auto Color = syntax::Enumerator;
-  if (attr == DW_AT_decl_file || attr == DW_AT_call_file) {
-    Color = syntax::String;
-    if (const auto *LT = u->getContext().getLineTableForUnit(u))
-      if (LT->getFileNameByIndex(
-             formValue.getAsUnsignedConstant().getValue(),
-             u->getCompilationDir(),
-             DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
-        File = '"' + File + '"';
-        Name = File;
-      }
-  } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
-    Name = AttributeValueString(attr, *Val);
-
-  if (!Name.empty())
-    WithColor(OS, Color) << Name;
-  else if (attr == DW_AT_decl_line || attr == DW_AT_call_line)
-    OS << *formValue.getAsUnsignedConstant();
-  else
-    formValue.dump(OS);
-
-  // We have dumped the attribute raw value. For some attributes
-  // having both the raw value and the pretty-printed value is
-  // interesting. These attributes are handled below.
-  if (attr == DW_AT_specification || attr == DW_AT_abstract_origin) {
-    Optional<uint64_t> Ref = formValue.getAsReference();
-    if (Ref.hasValue()) {
-      uint32_t RefOffset = Ref.getValue();
-      DWARFDebugInfoEntryMinimal DIE;
-      if (const DWARFUnit *RefU = findUnitAndExtractFast(DIE, u, &RefOffset))
-        if (const char *Name = DIE.getName(RefU, DINameKind::LinkageName))
-          OS << " \"" << Name << '\"';
-    }
-  } else if (attr == DW_AT_APPLE_property_attribute) {
-    if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
-      dumpApplePropertyAttribute(OS, *OptVal);
-  } else if (attr == DW_AT_ranges) {
-    dumpRanges(OS, getAddressRanges(u), u->getAddressByteSize(),
-               sizeof(BaseIndent)+indent+4);
-  }
-
-  OS << ")\n";
-}
-
-bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit &U,
+bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U,
                                              uint32_t *OffsetPtr) {
   DataExtractor DebugInfoData = U.getDebugInfoExtractor();
   const uint32_t UEndOffset = U.getNextUnitOffset();
   return extractFast(U, OffsetPtr, DebugInfoData, UEndOffset);
 }
-bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit &U,
+bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U,
                                              uint32_t *OffsetPtr,
                                              const DataExtractor &DebugInfoData,
                                              uint32_t UEndOffset) {
   Offset = *OffsetPtr;
   if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
     return false;
   uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
   if (0 == AbbrCode) {
if (Optional<uint8_t> FixedSize = AttrSpec.getByteSize(U)) {
       // We failed to skip this attribute's value, restore the original offset
       // and return the failure status.
       *OffsetPtr = Offset;
       return false;
     }
   }
   return true;
 }
-
-bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
-  return getTag() == DW_TAG_subprogram;
-}
-
-bool DWARFDebugInfoEntryMinimal::isSubroutineDIE() const {
-  uint32_t Tag = getTag();
-  return Tag == DW_TAG_subprogram ||
-         Tag == DW_TAG_inlined_subroutine;
-}
-
-bool DWARFDebugInfoEntryMinimal::getAttributeValue(const DWARFUnit *U, 
-    dwarf::Attribute Attr, DWARFFormValue &FormValue) const {
-  if (!AbbrevDecl || !U)
-    return false;
-  return AbbrevDecl->getAttributeValue(Offset, Attr, *U, FormValue);
-}
-
-const char *DWARFDebugInfoEntryMinimal::getAttributeValueAsString(
-    const DWARFUnit *U, dwarf::Attribute Attr, 
-    const char *FailValue) const {
-  DWARFFormValue FormValue;
-  if (!getAttributeValue(U, Attr, FormValue))
-    return FailValue;
-  Optional<const char *> Result = FormValue.getAsCString();
-  return Result.hasValue() ? Result.getValue() : FailValue;
-}
-
-uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsAddress(
-    const DWARFUnit *U, dwarf::Attribute Attr, 
-    uint64_t FailValue) const {
-  DWARFFormValue FormValue;
-  if (!getAttributeValue(U, Attr, FormValue))
-    return FailValue;
-  Optional<uint64_t> Result = FormValue.getAsAddress();
-  return Result.hasValue() ? Result.getValue() : FailValue;
-}
-
-int64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSignedConstant(
-    const DWARFUnit *U, dwarf::Attribute Attr, int64_t FailValue) const {
-  DWARFFormValue FormValue;
-  if (!getAttributeValue(U, Attr, FormValue))
-    return FailValue;
-  Optional<int64_t> Result = FormValue.getAsSignedConstant();
-  return Result.hasValue() ? Result.getValue() : FailValue;
-}
-
-uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsUnsignedConstant(
-    const DWARFUnit *U, dwarf::Attribute Attr, 
-    uint64_t FailValue) const {
-  DWARFFormValue FormValue;
-  if (!getAttributeValue(U, Attr, FormValue))
-    return FailValue;
-  Optional<uint64_t> Result = FormValue.getAsUnsignedConstant();
-  return Result.hasValue() ? Result.getValue() : FailValue;
-}
-
-uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsReference(
-    const DWARFUnit *U, dwarf::Attribute Attr, 
-    uint64_t FailValue) const {
-  DWARFFormValue FormValue;
-  if (!getAttributeValue(U, Attr, FormValue))
-    return FailValue;
-  Optional<uint64_t> Result = FormValue.getAsReference();
-  return Result.hasValue() ? Result.getValue() : FailValue;
-}
-
-uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSectionOffset(
-    const DWARFUnit *U, dwarf::Attribute Attr, 
-    uint64_t FailValue) const {
-  DWARFFormValue FormValue;
-  if (!getAttributeValue(U, Attr, FormValue))
-    return FailValue;
-  Optional<uint64_t> Result = FormValue.getAsSectionOffset();
-  return Result.hasValue() ? Result.getValue() : FailValue;
-}
-
-uint64_t
-DWARFDebugInfoEntryMinimal::getRangesBaseAttribute(const DWARFUnit *U,
-                                                   uint64_t FailValue) const {
-  uint64_t Result =
-      getAttributeValueAsSectionOffset(U, DW_AT_rnglists_base, -1ULL);
-  if (Result != -1ULL)
-    return Result;
-  return getAttributeValueAsSectionOffset(U, DW_AT_GNU_ranges_base, FailValue);
-}
-
-bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFUnit *U,
-                                                 uint64_t &LowPC,
-                                                 uint64_t &HighPC) const {
-  LowPC = getAttributeValueAsAddress(U, DW_AT_low_pc, -1ULL);
-  if (LowPC == -1ULL)
-    return false;
-  HighPC = getAttributeValueAsAddress(U, DW_AT_high_pc, -1ULL);
-  if (HighPC == -1ULL) {
-    // Since DWARF4, DW_AT_high_pc may also be of class constant, in which case
-    // it represents function size.
-    HighPC = getAttributeValueAsUnsignedConstant(U, DW_AT_high_pc, -1ULL);
-    if (HighPC != -1ULL)
-      HighPC += LowPC;
-  }
-  return (HighPC != -1ULL);
-}
-
-DWARFAddressRangesVector
-DWARFDebugInfoEntryMinimal::getAddressRanges(const DWARFUnit *U) const {
-  if (isNULL())
-    return DWARFAddressRangesVector();
-  // Single range specified by low/high PC.
-  uint64_t LowPC, HighPC;
-  if (getLowAndHighPC(U, LowPC, HighPC)) {
-    return DWARFAddressRangesVector(1, std::make_pair(LowPC, HighPC));
-  }
-  // Multiple ranges from .debug_ranges section.
-  uint32_t RangesOffset =
-      getAttributeValueAsSectionOffset(U, DW_AT_ranges, -1U);
-  if (RangesOffset != -1U) {
-    DWARFDebugRangeList RangeList;
-    if (U->extractRangeList(RangesOffset, RangeList))
-      return RangeList.getAbsoluteRanges(U->getBaseAddress());
-  }
-  return DWARFAddressRangesVector();
-}
-
-void DWARFDebugInfoEntryMinimal::collectChildrenAddressRanges(
-    const DWARFUnit *U, DWARFAddressRangesVector& Ranges) const {
-  if (isNULL())
-    return;
-  if (isSubprogramDIE()) {
-    const auto &DIERanges = getAddressRanges(U);
-    Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
-  }
-
-  const DWARFDebugInfoEntryMinimal *Child = getFirstChild();
-  while (Child) {
-    Child->collectChildrenAddressRanges(U, Ranges);
-    Child = Child->getSibling();
-  }
-}
-
-bool DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
-    const DWARFUnit *U, const uint64_t Address) const {
-  for (const auto& R : getAddressRanges(U)) {
-    if (R.first <= Address && Address < R.second)
-      return true;
-  }
-  return false;
-}
-
-const char *
-DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
-                                              DINameKind Kind) const {
-  if (!isSubroutineDIE())
-    return nullptr;
-  return getName(U, Kind);
-}
-
-const char *
-DWARFDebugInfoEntryMinimal::getName(const DWARFUnit *U,
-                                    DINameKind Kind) const {
-  if (Kind == DINameKind::None)
-    return nullptr;
-  // Try to get mangled name only if it was asked for.
-  if (Kind == DINameKind::LinkageName) {
-    if (const char *name =
-            getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
-      return name;
-    if (const char *name =
-            getAttributeValueAsString(U, DW_AT_linkage_name, nullptr))
-      return name;
-  }
-  if (const char *name = getAttributeValueAsString(U, DW_AT_name, nullptr))
-    return name;
-  // Try to get name from specification DIE.
-  uint32_t spec_ref =
-      getAttributeValueAsReference(U, DW_AT_specification, -1U);
-  if (spec_ref != -1U) {
-    DWARFDebugInfoEntryMinimal spec_die;
-    if (const DWARFUnit *RefU = findUnitAndExtractFast(spec_die, U, &spec_ref)) {
-      if (const char *name = spec_die.getName(RefU, Kind))
-        return name;
-    }
-  }
-  // Try to get name from abstract origin DIE.
-  uint32_t abs_origin_ref =
-      getAttributeValueAsReference(U, DW_AT_abstract_origin, -1U);
-  if (abs_origin_ref != -1U) {
-    DWARFDebugInfoEntryMinimal abs_origin_die;
-    if (const DWARFUnit *RefU = findUnitAndExtractFast(abs_origin_die, U,
-                                                       &abs_origin_ref)) {
-      if (const char *name = abs_origin_die.getName(RefU, Kind))
-        return name;
-    }
-  }
-  return nullptr;
-}
-
-void DWARFDebugInfoEntryMinimal::getCallerFrame(const DWARFUnit *U,
-                                                uint32_t &CallFile,
-                                                uint32_t &CallLine,
-                                                uint32_t &CallColumn) const {
-  CallFile = getAttributeValueAsUnsignedConstant(U, DW_AT_call_file, 0);
-  CallLine = getAttributeValueAsUnsignedConstant(U, DW_AT_call_line, 0);
-  CallColumn = getAttributeValueAsUnsignedConstant(U, DW_AT_call_column, 0);
-}
-
-DWARFDebugInfoEntryInlinedChain
-DWARFDebugInfoEntryMinimal::getInlinedChainForAddress(
-    const DWARFUnit *U, const uint64_t Address) const {
-  DWARFDebugInfoEntryInlinedChain InlinedChain;
-  InlinedChain.U = U;
-  if (isNULL())
-    return InlinedChain;
-  for (const DWARFDebugInfoEntryMinimal *DIE = this; DIE; ) {
-    // Append current DIE to inlined chain only if it has correct tag
-    // (e.g. it is not a lexical block).
-    if (DIE->isSubroutineDIE()) {
-      InlinedChain.DIEs.push_back(*DIE);
-    }
-    // Try to get child which also contains provided address.
-    const DWARFDebugInfoEntryMinimal *Child = DIE->getFirstChild();
-    while (Child) {
-      if (Child->addressRangeContainsAddress(U, Address)) {
-        // Assume there is only one such child.
-        break;
-      }
-      Child = Child->getSibling();
-    }
-    DIE = Child;
-  }
-  // Reverse the obtained chain to make the root of inlined chain last.
-  std::reverse(InlinedChain.DIEs.begin(), InlinedChain.DIEs.end());
-  return InlinedChain;
-}

lib/DebugInfo/DWARF/DWARFDie.cpp

+//===-- DWARFDie.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/DWARFDie.h"
+#include "SyntaxHighlighting.h"
+#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+using namespace dwarf;
+using namespace syntax;
+
+namespace {
+ static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
+  OS << " (";
+  do {
+    uint64_t Shift = countTrailingZeros(Val);
+    assert(Shift < 64 && "undefined behavior");
+    uint64_t Bit = 1ULL << Shift;
+    auto PropName = ApplePropertyString(Bit);
+    if (!PropName.empty())
+      OS << PropName;
+    else
+      OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
+    if (!(Val ^= Bit))
+      break;
+    OS << ", ";
+  } while (true);
+  OS << ")";
+}
+
+static void dumpRanges(raw_ostream &OS, const DWARFAddressRangesVector& Ranges,
+                       unsigned AddressSize, unsigned Indent) {
+  if (Ranges.empty())
+    return;
+  
+  for (const auto &Range: Ranges) {
+    OS << '\n';
+    OS.indent(Indent);
+    OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")",
+                 AddressSize*2, Range.first,
+                 AddressSize*2, Range.second);
+  }
+}
+
+static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
+                          uint32_t *OffsetPtr, dwarf::Attribute Attr,
+                          dwarf::Form Form, unsigned Indent) {
+  if (!Die.isValid())
+    return;
+  const char BaseIndent[] = "            ";
+  OS << BaseIndent;
+  OS.indent(Indent+2);
+  auto attrString = AttributeString(Attr);
+  if (!attrString.empty())
+    WithColor(OS, syntax::Attribute) << attrString;
+  else
+    WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", Attr);
+  
+  auto formString = FormEncodingString(Form);
+  if (!formString.empty())
+    OS << " [" << formString << ']';
+  else
+    OS << format(" [DW_FORM_Unknown_%x]", Form);
+  
+  DWARFUnit *U = Die.getDwarfUnit();
+  DWARFFormValue formValue(Form);
+  
+  if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr, U))
+    return;
+  
+  OS << "\t(";
+  
+  StringRef Name;
+  std::string File;
+  auto Color = syntax::Enumerator;
+  if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
+    Color = syntax::String;
+    if (const auto *LT = U->getContext().getLineTableForUnit(U))
+      if (LT->getFileNameByIndex(formValue.getAsUnsignedConstant().getValue(), U->getCompilationDir(), DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
+        File = '"' + File + '"';
+        Name = File;
+      }
+  } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
+    Name = AttributeValueString(Attr, *Val);
+  
+  if (!Name.empty())
+    WithColor(OS, Color) << Name;
+  else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
+    OS << *formValue.getAsUnsignedConstant();
+  else
+    formValue.dump(OS);
+  
+  // We have dumped the attribute raw value. For some attributes
+  // having both the raw value and the pretty-printed value is
+  // interesting. These attributes are handled below.
+  if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
+    if (const char *Name = Die.getAttributeValueAsReferencedDie(Attr).getName(DINameKind::LinkageName))
+        OS << " \"" << Name << '\"';
+  } else if (Attr == DW_AT_APPLE_property_attribute) {
+    if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
+      dumpApplePropertyAttribute(OS, *OptVal);
+  } else if (Attr == DW_AT_ranges) {
+    dumpRanges(OS, Die.getAddressRanges(), U->getAddressByteSize(),
+               sizeof(BaseIndent)+Indent+4);
+  }
+  
+  OS << ")\n";
+}
+
+} // end anonymous namespace
+
+bool DWARFDie::isSubprogramDIE() const {
+  return getTag() == DW_TAG_subprogram;
+}
+
+bool DWARFDie::isSubroutineDIE() const {
+  auto Tag = getTag();
+  return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
+}
+
+bool DWARFDie::getAttributeValue(dwarf::Attribute Attr,
+                                 DWARFFormValue &FormValue) const {
+  if (!U)
+    return false;
+  auto AbbrevDecl = getAbbreviationDeclarationPtr();
+  if (AbbrevDecl)
+    return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U, FormValue);
+  return false;
+}
+
+const char *DWARFDie::getAttributeValueAsString(dwarf::Attribute Attr,
+                                                const char *FailValue) const {
+  DWARFFormValue FormValue;
+  if (!getAttributeValue(Attr, FormValue))
+    return FailValue;
+  Optional<const char *> Result = FormValue.getAsCString();
+  return Result.hasValue() ? Result.getValue() : FailValue;
+}
+
+uint64_t DWARFDie::getAttributeValueAsAddress(dwarf::Attribute Attr,
+                                              uint64_t FailValue) const {
+  DWARFFormValue FormValue;
+  if (!getAttributeValue(Attr, FormValue))
+    return FailValue;
+  Optional<uint64_t> Result = FormValue.getAsAddress();
+  return Result.hasValue() ? Result.getValue() : FailValue;
+}
+
+int64_t DWARFDie::getAttributeValueAsSignedConstant(dwarf::Attribute Attr,
+                                                    int64_t FailValue) const {
+  DWARFFormValue FormValue;
+  if (!getAttributeValue(Attr, FormValue))
+    return FailValue;
+  Optional<int64_t> Result = FormValue.getAsSignedConstant();
+  return Result.hasValue() ? Result.getValue() : FailValue;
+}
+
+uint64_t
+DWARFDie::getAttributeValueAsUnsignedConstant(dwarf::Attribute Attr,
+                                              uint64_t FailValue) const {
+  DWARFFormValue FormValue;
+  if (!getAttributeValue(Attr, FormValue))
+    return FailValue;
+  Optional<uint64_t> Result = FormValue.getAsUnsignedConstant();
+  return Result.hasValue() ? Result.getValue() : FailValue;
+}
+
+uint64_t DWARFDie::getAttributeValueAsReference(dwarf::Attribute Attr,
+                                                uint64_t FailValue) const {
+  DWARFFormValue FormValue;
+  if (!getAttributeValue(Attr, FormValue))
+    return FailValue;
+  Optional<uint64_t> Result = FormValue.getAsReference();
+  return Result.hasValue() ? Result.getValue() : FailValue;
+}
+
+uint64_t DWARFDie::getAttributeValueAsSectionOffset(dwarf::Attribute Attr,
+                                                    uint64_t FailValue) const {
+  DWARFFormValue FormValue;
+  if (!getAttributeValue(Attr, FormValue))
+    return FailValue;
+  Optional<uint64_t> Result = FormValue.getAsSectionOffset();
+  return Result.hasValue() ? Result.getValue() : FailValue;
+}
+
+DWARFDie
+DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
+  uint32_t SpecRef = getAttributeValueAsReference(Attr, -1U);
+  if (SpecRef != -1U) {
+    auto SpecUnit = U->getUnitSection().getUnitForOffset(SpecRef);
+    if (SpecUnit)
+      return SpecUnit->getDIEForOffset(SpecRef);
+  }
+  return DWARFDie();
+}
+
+uint64_t
+DWARFDie::getRangesBaseAttribute(uint64_t FailValue) const {
+  auto Result = getAttributeValueAsSectionOffset(DW_AT_rnglists_base, -1ULL);
+  if (Result != -1ULL)
+    return Result;
+  return getAttributeValueAsSectionOffset(DW_AT_GNU_ranges_base, FailValue);
+}
+
+bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC) const {
+  LowPC = getAttributeValueAsAddress(DW_AT_low_pc, -1ULL);
+  if (LowPC == -1ULL)
+    return false;
+  HighPC = getAttributeValueAsAddress(DW_AT_high_pc, -1ULL);
+  if (HighPC == -1ULL) {
+    // Since DWARF4, DW_AT_high_pc may also be of class constant, in which case
+    // it represents function size.
+    HighPC = getAttributeValueAsUnsignedConstant(DW_AT_high_pc, -1ULL);
+    if (HighPC != -1ULL)
+      HighPC += LowPC;
+  }
+  return (HighPC != -1ULL);
+}
+
+DWARFAddressRangesVector
+DWARFDie::getAddressRanges() const {
+  if (isNULL())
+    return DWARFAddressRangesVector();
+  // Single range specified by low/high PC.
+  uint64_t LowPC, HighPC;
+  if (getLowAndHighPC(LowPC, HighPC)) {
+    return DWARFAddressRangesVector(1, std::make_pair(LowPC, HighPC));
+  }
+  // Multiple ranges from .debug_ranges section.
+  uint32_t RangesOffset = getAttributeValueAsSectionOffset(DW_AT_ranges, -1U);
+  if (RangesOffset != -1U) {
+    DWARFDebugRangeList RangeList;
+    if (U->extractRangeList(RangesOffset, RangeList))
+      return RangeList.getAbsoluteRanges(U->getBaseAddress());
+  }
+  return DWARFAddressRangesVector();
+}
+
+void
+DWARFDie::collectChildrenAddressRanges(DWARFAddressRangesVector& Ranges) const {
+  if (isNULL())
+    return;
+  if (isSubprogramDIE()) {
+    const auto &DIERanges = getAddressRanges();
+    Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
+  }
+
+  DWARFDie Child = getFirstChild();
+  while (Child) {
+    Child.collectChildrenAddressRanges(Ranges);
+    Child = Child.getSibling();
+  }
+}
+
+bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
+  for (const auto& R : getAddressRanges()) {
+    if (R.first <= Address && Address < R.second)
+      return true;
+  }
+  return false;
+}
+
+const char *
+DWARFDie::getSubroutineName(DINameKind Kind) const {
+  if (!isSubroutineDIE())
+    return nullptr;
+  return getName(Kind);
+}
+
+const char *
+DWARFDie::getName(DINameKind Kind) const {
+  if (!isValid() || Kind == DINameKind::None)
+    return nullptr;
+  const char *name = nullptr;
+  // Try to get mangled name only if it was asked for.
+  if (Kind == DINameKind::LinkageName) {
+    if ((name = getAttributeValueAsString(DW_AT_MIPS_linkage_name, nullptr)))
+      return name;
+    if ((name = getAttributeValueAsString(DW_AT_linkage_name, nullptr)))
+      return name;
+  }
+  if ((name = getAttributeValueAsString(DW_AT_name, nullptr)))
+    return name;
+  // Try to get name from specification DIE.
+  DWARFDie SpecDie = getAttributeValueAsReferencedDie(DW_AT_specification);
+  if (SpecDie && (name = SpecDie.getName(Kind)))
+    return name;
+  // Try to get name from abstract origin DIE.
+  DWARFDie AbsDie = getAttributeValueAsReferencedDie(DW_AT_abstract_origin);
+  if (AbsDie && (name = AbsDie.getName(Kind)))
+    return name;
+  return nullptr;
+}
+
+void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
+                              uint32_t &CallColumn) const {
+  CallFile = getAttributeValueAsUnsignedConstant(DW_AT_call_file, 0);
+  CallLine = getAttributeValueAsUnsignedConstant(DW_AT_call_line, 0);
+  CallColumn = getAttributeValueAsUnsignedConstant(DW_AT_call_column, 0);
+}
+
+void DWARFDie::dump(raw_ostream &OS, unsigned RecurseDepth,
+                    unsigned Indent) const {
+  if (!isValid())
+    return;
+  DataExtractor debug_info_data = U->getDebugInfoExtractor();
+  const uint32_t Offset = getOffset();
+  uint32_t offset = Offset;
+  
+  if (debug_info_data.isValidOffset(offset)) {
+    uint32_t abbrCode = debug_info_data.getULEB128(&offset);
+    WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
+    
+    if (abbrCode) {
+      auto AbbrevDecl = getAbbreviationDeclarationPtr();
+      if (AbbrevDecl) {
+        auto tagString = TagString(getTag());
+        if (!tagString.empty())
+          WithColor(OS, syntax::Tag).get().indent(Indent) << tagString;
+        else
+          WithColor(OS, syntax::Tag).get().indent(Indent)
+          << format("DW_TAG_Unknown_%x", getTag());
+        
+        OS << format(" [%u] %c\n", abbrCode,
+                     AbbrevDecl->hasChildren() ? '*' : ' ');
+        
+        // Dump all data in the DIE for the attributes.
+        for (const auto &AttrSpec : AbbrevDecl->attributes()) {
+          dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
+                        Indent);
+        }
+        
+        DWARFDie child = getFirstChild();
+        if (RecurseDepth > 0 && child) {
+          while (child) {
+            child.dump(OS, RecurseDepth-1, Indent+2);
+            child = child.getSibling();
+          }
+        }
+      } else {
+        OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
+        << abbrCode << '\n';
+      }
+    } else {
+      OS.indent(Indent) << "NULL\n";
+    }
+  }
+}
+
+
+SmallVector<DWARFDie, 4>
+DWARFDie::getInlinedChainForAddress(const uint64_t Address) const {
+  SmallVector<DWARFDie, 4> InlinedChain;
+  if (isNULL())
+    return InlinedChain;
+  DWARFDie DIE(*this);
+  while (DIE) {
+    // Append current DIE to inlined chain only if it has correct tag
+    // (e.g. it is not a lexical block).
+    if (DIE.isSubroutineDIE())
+      InlinedChain.push_back(DIE);
+
+    // Try to get child which also contains provided address.
+    DWARFDie Child = DIE.getFirstChild();
+    while (Child) {
+      if (Child.addressRangeContainsAddress(Address)) {
+        // Assume there is only one such child.
+        break;
+      }
+      Child = Child.getSibling();
+    }
+    DIE = Child;
+  }
+  // Reverse the obtained chain to make the root of inlined chain last.
+  std::reverse(InlinedChain.begin(), InlinedChain.end());
+  return InlinedChain;
+}
+

lib/DebugInfo/DWARF/DWARFTypeUnit.cpp

bool DWARFTypeUnit::extractImpl(DataExtractor debug_info,
   if (!DWARFUnit::extractImpl(debug_info, offset_ptr))
     return false;
   TypeHash = debug_info.getU64(offset_ptr);
   TypeOffset = debug_info.getU32(offset_ptr);
   return TypeOffset < getLength();
 }
 
 void DWARFTypeUnit::dump(raw_ostream &OS, bool SummarizeTypes) {
-  const DWARFDebugInfoEntryMinimal *TD =
-      getDIEForOffset(TypeOffset + getOffset());
+  DWARFDie TD = getDIEForOffset(TypeOffset + getOffset());
   DWARFFormValue NameVal;
   const char *Name = "";
-  if (TD->getAttributeValue(this, llvm::dwarf::DW_AT_name, NameVal))
+  if (TD.getAttributeValue(llvm::dwarf::DW_AT_name, NameVal))
     if (auto ON = NameVal.getAsCString())
       Name = *ON;
 
   if (SummarizeTypes) {
     OS << "name = '" << Name << "'"
        << " type_signature = " << format("0x%16" PRIx64, TypeHash)
        << " length = " << format("0x%08x", getLength()) << '\n';
     return;
   }
 
   OS << format("0x%08x", getOffset()) << ": Type Unit:"
      << " length = " << format("0x%08x", getLength())
      << " version = " << format("0x%04x", getVersion())
      << " abbr_offset = " << format("0x%04x", getAbbreviations()->getOffset())
      << " addr_size = " << format("0x%02x", getAddressByteSize())
      << " name = '" << Name << "'"
      << " type_signature = " << format("0x%16" PRIx64, TypeHash)
      << " type_offset = " << format("0x%04x", TypeOffset)
      << " (next unit at " << format("0x%08x", getNextUnitOffset()) << ")\n";
 
-  if (const DWARFDebugInfoEntryMinimal *TU = getUnitDIE(false))
-    TU->dump(OS, this, -1U);
+  if (DWARFDie TU = getUnitDIE(false))
+    TU.dump(OS, -1U);
   else
     OS << "<type unit can't be parsed!>\n\n";
 }

lib/DebugInfo/DWARF/DWARFUnit.cpp

void DWARFUnit::clear() {
   BaseAddr = 0;
   RangeSectionBase = 0;
   AddrOffsetSectionBase = 0;
   clearDIEs(false);
   DWO.reset();
 }
 
 const char *DWARFUnit::getCompilationDir() {
-  extractDIEsIfNeeded(true);
-  if (DieArray.empty())
-    return nullptr;
-  return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
+  return getUnitDIE().getAttributeValueAsString(DW_AT_comp_dir, nullptr);
 }
 
 uint64_t DWARFUnit::getDWOId() {
-  extractDIEsIfNeeded(true);
-  const uint64_t FailValue = -1ULL;
-  if (DieArray.empty())
-    return FailValue;
-  return DieArray[0]
-      .getAttributeValueAsUnsignedConstant(this, DW_AT_GNU_dwo_id, FailValue);
+  return getUnitDIE().getAttributeValueAsUnsignedConstant(DW_AT_GNU_dwo_id,
+                                                          -1ULL);
 }
 
 void DWARFUnit::setDIERelations() {
   if (DieArray.size() <= 1)
     return;
 
-  std::vector<DWARFDebugInfoEntryMinimal *> ParentChain;
-  DWARFDebugInfoEntryMinimal *SiblingChain = nullptr;
+  std::vector<DWARFDebugInfoEntry *> ParentChain;
+  DWARFDebugInfoEntry *SiblingChain = nullptr;
   for (auto &DIE : DieArray) {
     if (SiblingChain) {
       SiblingChain->setSibling(&DIE);
     }
     if (const DWARFAbbreviationDeclaration *AbbrDecl =
             DIE.getAbbreviationDeclarationPtr()) {
       // Normal DIE.
       if (AbbrDecl->hasChildren()) {
for (auto &DIE : DieArray) {
     }
   }
   assert(SiblingChain == nullptr || SiblingChain == &DieArray[0]);
   assert(ParentChain.empty());
 }
 
 void DWARFUnit::extractDIEsToVector(
     bool AppendCUDie, bool AppendNonCUDies,
-    std::vector<DWARFDebugInfoEntryMinimal> &Dies) const {
+    std::vector<DWARFDebugInfoEntry> &Dies) const {
   if (!AppendCUDie && !AppendNonCUDies)
     return;
 
   // Set the offset to that of the first DIE and calculate the start of the
   // next compilation unit header.
   uint32_t DIEOffset = Offset + getHeaderSize();
   uint32_t NextCUOffset = getNextUnitOffset();
-  DWARFDebugInfoEntryMinimal DIE;
+  DWARFDebugInfoEntry DIE;
   DataExtractor DebugInfoData = getDebugInfoExtractor();
   uint32_t Depth = 0;
   bool IsCUDie = true;
 
   while (DIE.extractFast(*this, &DIEOffset, DebugInfoData, NextCUOffset)) {
     if (IsCUDie) {
       if (AppendCUDie)
         Dies.push_back(DIE);
size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
   bool HasCUDie = !DieArray.empty();
   extractDIEsToVector(!HasCUDie, !CUDieOnly, DieArray);
 
   if (DieArray.empty())
     return 0;
 
   // If CU DIE was just parsed, copy several attribute values from it.
   if (!HasCUDie) {
-    uint64_t BaseAddr =
-        DieArray[0].getAttributeValueAsAddress(this, DW_AT_low_pc, -1ULL);
+    DWARFDie UnitDie = getUnitDIE();
+    uint64_t BaseAddr = UnitDie.getAttributeValueAsAddress(DW_AT_low_pc, -1ULL);
     if (BaseAddr == -1ULL)
-      BaseAddr = DieArray[0].getAttributeValueAsAddress(this, DW_AT_entry_pc, 0);
+      BaseAddr = UnitDie.getAttributeValueAsAddress(DW_AT_entry_pc, 0);
     setBaseAddress(BaseAddr);
-    AddrOffsetSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
-        this, DW_AT_GNU_addr_base, 0);
-    RangeSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
-        this, DW_AT_rnglists_base, 0);
+    AddrOffsetSectionBase = UnitDie.getAttributeValueAsSectionOffset(
+        DW_AT_GNU_addr_base, 0);
+    RangeSectionBase = UnitDie.getAttributeValueAsSectionOffset(
+        DW_AT_rnglists_base, 0);
     // Don't fall back to DW_AT_GNU_ranges_base: it should be ignored for
     // skeleton CU DIE, so that DWARF users not aware of it are not broken.
   }
 
   setDIERelations();
   return DieArray.size();
 }
 
if (DWOContext->getNumDWOCompileUnits() > 0)
     DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
 }
 
 bool DWARFUnit::parseDWO() {
   if (isDWO)
     return false;
   if (DWO.get())
     return false;
-  extractDIEsIfNeeded(true);
-  if (DieArray.empty())
+  DWARFDie UnitDie = getUnitDIE();
+  if (!UnitDie)
     return false;
   const char *DWOFileName =
-      DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, nullptr);
+      UnitDie.getAttributeValueAsString(DW_AT_GNU_dwo_name, nullptr);
   if (!DWOFileName)
     return false;
   const char *CompilationDir =
-      DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
+      UnitDie.getAttributeValueAsString(DW_AT_comp_dir, nullptr);
   SmallString<16> AbsolutePath;
   if (sys::path::is_relative(DWOFileName) && CompilationDir != nullptr) {
     sys::path::append(AbsolutePath, CompilationDir);
   }
   sys::path::append(AbsolutePath, DWOFileName);
   DWO = llvm::make_unique<DWOHolder>(AbsolutePath);
   DWARFUnit *DWOCU = DWO->getUnit();
   // Verify that compile unit in .dwo file is valid.
   if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {
     DWO.reset();
     return false;
   }
   // Share .debug_addr and .debug_ranges section with compile unit in .dwo
   DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
-  uint32_t DWORangesBase = DieArray[0].getRangesBaseAttribute(this, 0);
+  uint32_t DWORangesBase = UnitDie.getRangesBaseAttribute(0);
   DWOCU->setRangesSection(RangeSection, DWORangesBase);
   return true;
 }
 
 void DWARFUnit::clearDIEs(bool KeepCUDie) {
   if (DieArray.size() > (unsigned)KeepCUDie) {
     // std::vectors never get any smaller when resized to a smaller size,
     // or when clear() or erase() are called, the size will report that it
     // is smaller, but the memory allocated remains intact (call capacity()
     // to see this). So we need to create a temporary vector and swap the
     // contents which will cause just the internal pointers to be swapped
     // so that when temporary vector goes out of scope, it will destroy the
     // contents.
-    std::vector<DWARFDebugInfoEntryMinimal> TmpArray;
+    std::vector<DWARFDebugInfoEntry> TmpArray;
     DieArray.swap(TmpArray);
     // Save at least the compile unit DIE
     if (KeepCUDie)
       DieArray.push_back(TmpArray.front());
   }
 }
 
 void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
-  const auto *U = getUnitDIE();
-  if (U == nullptr)
+  DWARFDie UnitDie = getUnitDIE();
+  if (!UnitDie)
     return;
   // First, check if unit DIE describes address ranges for the whole unit.
-  const auto &CUDIERanges = U->getAddressRanges(this);
+  const auto &CUDIERanges = UnitDie.getAddressRanges();
   if (!CUDIERanges.empty()) {
     CURanges.insert(CURanges.end(), CUDIERanges.begin(), CUDIERanges.end());
     return;
   }
 
   // This function is usually called if there in no .debug_aranges section
   // in order to produce a compile unit level set of address ranges that
   // is accurate. If the DIEs weren't parsed, then we don't want all dies for
   // all compile units to stay loaded when they weren't needed. So we can end
   // up parsing the DWARF and then throwing them all away to keep memory usage
   // down.
   const bool ClearDIEs = extractDIEsIfNeeded(false) > 1;
-  DieArray[0].collectChildrenAddressRanges(this, CURanges);
+  getUnitDIE().collectChildrenAddressRanges(CURanges);
 
   // Collect address ranges from DIEs in .dwo if necessary.
   bool DWOCreated = parseDWO();
   if (DWO.get())
     DWO->getUnit()->collectAddressRanges(CURanges);
   if (DWOCreated)
     DWO.reset();
 
   // Keep memory down by clearing DIEs if this generate function
   // caused them to be parsed.
   if (ClearDIEs)
     clearDIEs(true);
 }
 
-const DWARFDebugInfoEntryMinimal *
+DWARFDie
 DWARFUnit::getSubprogramForAddress(uint64_t Address) {
   extractDIEsIfNeeded(false);
-  for (const DWARFDebugInfoEntryMinimal &DIE : DieArray) {
+  for (const DWARFDebugInfoEntry &D : DieArray) {
+    DWARFDie DIE(this, &D);
     if (DIE.isSubprogramDIE() &&
-        DIE.addressRangeContainsAddress(this, Address)) {
-      return &DIE;
+        DIE.addressRangeContainsAddress(Address)) {
+      return DIE;
     }
   }
-  return nullptr;
+  return DWARFDie();
 }
 
-DWARFDebugInfoEntryInlinedChain
+SmallVector<DWARFDie, 4>
 DWARFUnit::getInlinedChainForAddress(uint64_t Address) {
   // First, find a subprogram that contains the given address (the root
   // of inlined chain).
-  const DWARFUnit *ChainCU = nullptr;
-  const DWARFDebugInfoEntryMinimal *SubprogramDIE;
+  DWARFDie SubprogramDIE;
   // Try to look for subprogram DIEs in the DWO file.
   parseDWO();
-  if (DWO) {
-    if ((SubprogramDIE = DWO->getUnit()->getSubprogramForAddress(Address)))
-      ChainCU = DWO->getUnit();
-  } else if ((SubprogramDIE = getSubprogramForAddress(Address)))
-    ChainCU = this;
+  if (DWO)
+    SubprogramDIE = DWO->getUnit()->getSubprogramForAddress(Address);
+  else
+    SubprogramDIE = getSubprogramForAddress(Address);
 
   // Get inlined chain rooted at this subprogram DIE.
   if (!SubprogramDIE)
-    return DWARFDebugInfoEntryInlinedChain();
-  return SubprogramDIE->getInlinedChainForAddress(ChainCU, Address);
+    return SmallVector<DWARFDie, 4>();
+  return SubprogramDIE.getInlinedChainForAddress(Address);
 }
 
 const DWARFUnitIndex &getDWARFUnitIndex(DWARFContext &Context,
                                         DWARFSectionKind Kind) {
   if (Kind == DW_SECT_INFO)
     return Context.getCUIndex();
   assert(Kind == DW_SECT_TYPES);
   return Context.getTUIndex();
 }
 
 } // end namespace llvm

tools/dsymutil/DwarfLinker.cpp

 class DeclContext {
   unsigned QualifiedNameHash;
   uint32_t Line;
   uint32_t ByteSize;
   uint16_t Tag;
   StringRef Name;
   StringRef File;
   const DeclContext &Parent;
-  const DWARFDebugInfoEntryMinimal *LastSeenDIE;
+  DWARFDie LastSeenDIE;
   uint32_t LastSeenCompileUnitID;
   uint32_t CanonicalDIEOffset;
 
   friend DeclMapInfo;
 
 public:
   typedef DenseSet<DeclContext *, DeclMapInfo> Map;
 
   DeclContext()
       : QualifiedNameHash(0), Line(0), ByteSize(0),
         Tag(dwarf::DW_TAG_compile_unit), Name(), File(), Parent(*this),
-        LastSeenDIE(nullptr), LastSeenCompileUnitID(0), CanonicalDIEOffset(0) {}
+        LastSeenDIE(), LastSeenCompileUnitID(0), CanonicalDIEOffset(0) {}
 
   DeclContext(unsigned Hash, uint32_t Line, uint32_t ByteSize, uint16_t Tag,
               StringRef Name, StringRef File, const DeclContext &Parent,
-              const DWARFDebugInfoEntryMinimal *LastSeenDIE = nullptr,
-              unsigned CUId = 0)
+              DWARFDie LastSeenDIE = DWARFDie(), unsigned CUId = 0)
       : QualifiedNameHash(Hash), Line(Line), ByteSize(ByteSize), Tag(Tag),
         Name(Name), File(File), Parent(Parent), LastSeenDIE(LastSeenDIE),
         LastSeenCompileUnitID(CUId), CanonicalDIEOffset(0) {}
 
   uint32_t getQualifiedNameHash() const { return QualifiedNameHash; }
 
-  bool setLastSeenDIE(CompileUnit &U, const DWARFDebugInfoEntryMinimal *Die);
+  bool setLastSeenDIE(CompileUnit &U, const DWARFDie &Die);
 
   uint32_t getCanonicalDIEOffset() const { return CanonicalDIEOffset; }
   void setCanonicalDIEOffset(uint32_t Offset) { CanonicalDIEOffset = Offset; }
 
   uint16_t getTag() const { return Tag; }
   StringRef getName() const { return Name; }
 };
 
public:
   /// \returns The child DeclContext along with one bit that is set if
   /// this context is invalid.
   /// An invalid context means it shouldn't be considered for uniquing, but its
   /// not returning null, because some children of that context might be
   /// uniquing candidates.  FIXME: The invalid bit along the return value is to
   /// emulate some dsymutil-classic functionality.
   PointerIntPair<DeclContext *, 1>
   getChildDeclContext(DeclContext &Context,
-                      const DWARFDebugInfoEntryMinimal *DIE, CompileUnit &Unit,
+                      const DWARFDie &DIE, CompileUnit &Unit,
                       NonRelocatableStringpool &StringPool, bool InClangModule);
 
   DeclContext &getRoot() { return Root; }
 };
 
 /// \brief Stores all information relating to a compile unit, be it in
 /// its original instance in the object file to its brand new cloned
 /// and linked DIE tree.
struct DIEInfo {
     bool InDebugMap : 1;///< Was this DIE's entity found in the map?
     bool Prune : 1;     ///< Is this a pure forward declaration we can strip?
   };
 
   CompileUnit(DWARFUnit &OrigUnit, unsigned ID, bool CanUseODR,
               StringRef ClangModuleName)
       : OrigUnit(OrigUnit), ID(ID), NewUnit(OrigUnit.getVersion(),
                                             OrigUnit.getAddressByteSize(),
-                                            OrigUnit.getUnitDIE()->getTag()),
+                                            OrigUnit.getUnitDIE().getTag()),
           LowPc(UINT64_MAX), HighPc(0), RangeAlloc(), Ranges(RangeAlloc),
           ClangModuleName(ClangModuleName) {
     Info.resize(OrigUnit.getNumDIEs());
 
-    const auto *CUDie = OrigUnit.getUnitDIE(false);
-    unsigned Lang = CUDie->getAttributeValueAsUnsignedConstant(
-        &OrigUnit, dwarf::DW_AT_language, 0);
+    auto CUDie = OrigUnit.getUnitDIE(false);
+    unsigned Lang = CUDie.getAttributeValueAsUnsignedConstant(dwarf::DW_AT_language, 0);
     HasODR = CanUseODR && (Lang == dwarf::DW_LANG_C_plus_plus ||
                            Lang == dwarf::DW_LANG_C_plus_plus_03 ||
                            Lang == dwarf::DW_LANG_C_plus_plus_11 ||
                            Lang == dwarf::DW_LANG_C_plus_plus_14 ||
                            Lang == dwarf::DW_LANG_ObjC_plus_plus);
   }
 
   DWARFUnit &getOrigUnit() const { return OrigUnit; }
if (Attributes.empty())
     return;
 
   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection());
 
   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
   const DWARFSection &InputSec = Dwarf.getLocSection();
   DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(), AddressSize);
   DWARFUnit &OrigUnit = Unit.getOrigUnit();
-  const auto *OrigUnitDie = OrigUnit.getUnitDIE(false);
+  auto OrigUnitDie = OrigUnit.getUnitDIE(false);
   int64_t UnitPcOffset = 0;
-  uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress(
-      &OrigUnit, dwarf::DW_AT_low_pc, -1ULL);
+  uint64_t OrigLowPc = OrigUnitDie.getAttributeValueAsAddress(
+      dwarf::DW_AT_low_pc, -1ULL);
   if (OrigLowPc != -1ULL)
     UnitPcOffset = int64_t(OrigLowPc) - Unit.getLowPc();
 
   for (const auto &Attr : Attributes) {
     uint32_t Offset = Attr.first.get();
     Attr.first.set(LocSectionSize);
     // This is the quantity to add to the old location address to get
     // the correct address for the new one.

 public:
   DwarfLinker(StringRef OutputFilename, const LinkOptions &Options)
       : OutputFilename(OutputFilename), Options(Options),
         BinHolder(Options.Verbose), LastCIEOffset(0) {}
 
   /// \brief Link the contents of the DebugMap.
   bool link(const DebugMap &);
 
-  void reportWarning(const Twine &Warning, const DWARFUnit *Unit = nullptr,
-                     const DWARFDebugInfoEntryMinimal *DIE = nullptr) const;
+  void reportWarning(const Twine &Warning,
+                     const DWARFDie *DIE = nullptr) const;
 
 private:
   /// \brief Called at the start of a debug object link.
   void startDebugObject(DWARFContext &, DebugMapObject &);
 
   /// \brief Called at the end of a debug object link.
   void endDebugObject();
 
private:
   };
 
   /// \defgroup FindRootDIEs Find DIEs corresponding to debug map entries.
   ///
   /// @{
   /// \brief Recursively walk the \p DIE tree and look for DIEs to
   /// keep. Store that information in \p CU's DIEInfo.
   void lookForDIEsToKeep(RelocationManager &RelocMgr,
-                         const DWARFDebugInfoEntryMinimal &DIE,
+                         const DWARFDie &DIE,
                          const DebugMapObject &DMO, CompileUnit &CU,
                          unsigned Flags);
 
   /// If this compile unit is really a skeleton CU that points to a
   /// clang module, register it in ClangModules and return true.
   ///
   /// A skeleton CU is a CU without children, a DW_AT_gnu_dwo_name
   /// pointing to the module, and a DW_AT_gnu_dwo_id with the module
   /// hash.
-  bool registerModuleReference(const DWARFDebugInfoEntryMinimal &CUDie,
+  bool registerModuleReference(const DWARFDie &CUDie,
                                const DWARFUnit &Unit, DebugMap &ModuleMap,
                                unsigned Indent = 0);
 
   /// Recursively add the debug info in this clang module .pcm
   /// file (and all the modules imported by it in a bottom-up fashion)
   /// to Units.
   void loadClangModule(StringRef Filename, StringRef ModulePath,
                        StringRef ModuleName, uint64_t DwoId,
                        DebugMap &ModuleMap, unsigned Indent = 0);
 
   /// \brief Flags passed to DwarfLinker::lookForDIEsToKeep
   enum TravesalFlags {
     TF_Keep = 1 << 0,            ///< Mark the traversed DIEs as kept.
     TF_InFunctionScope = 1 << 1, ///< Current scope is a fucntion scope.
     TF_DependencyWalk = 1 << 2,  ///< Walking the dependencies of a kept DIE.
     TF_ParentWalk = 1 << 3,      ///< Walking up the parents of a kept DIE.
     TF_ODR = 1 << 4,             ///< Use the ODR whhile keeping dependants.
     TF_SkipPC = 1 << 5,          ///< Skip all location attributes.
   };
 
   /// \brief Mark the passed DIE as well as all the ones it depends on
   /// as kept.
   void keepDIEAndDependencies(RelocationManager &RelocMgr,
-                               const DWARFDebugInfoEntryMinimal &DIE,
+                               const DWARFDie &DIE,
                                CompileUnit::DIEInfo &MyInfo,
                                const DebugMapObject &DMO, CompileUnit &CU,
                                bool UseODR);
 
   unsigned shouldKeepDIE(RelocationManager &RelocMgr,
-                         const DWARFDebugInfoEntryMinimal &DIE,
+                         const DWARFDie &DIE,
                          CompileUnit &Unit, CompileUnit::DIEInfo &MyInfo,
                          unsigned Flags);
 
   unsigned shouldKeepVariableDIE(RelocationManager &RelocMgr,
-                                 const DWARFDebugInfoEntryMinimal &DIE,
+                                 const DWARFDie &DIE,
                                  CompileUnit &Unit,
                                  CompileUnit::DIEInfo &MyInfo, unsigned Flags);
 
   unsigned shouldKeepSubprogramDIE(RelocationManager &RelocMgr,
-                                   const DWARFDebugInfoEntryMinimal &DIE,
+                                   const DWARFDie &DIE,
                                    CompileUnit &Unit,
                                    CompileUnit::DIEInfo &MyInfo,
                                    unsigned Flags);
 
   bool hasValidRelocation(uint32_t StartOffset, uint32_t EndOffset,
                           CompileUnit::DIEInfo &Info);
   /// @}
 
public:
     /// debug map.
     ///
     /// \param OutOffset is the offset the cloned DIE in the output
     /// compile unit.
     /// \param PCOffset (while cloning a function scope) is the offset
     /// applied to the entry point of the function to get the linked address.
     /// \param Die the output DIE to use, pass NULL to create one.
     /// \returns the root of the cloned tree or null if nothing was selected.
-    DIE *cloneDIE(const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &U,
+    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);
 
struct AttributesInfo {
       AttributesInfo()
           : Name(nullptr), MangledName(nullptr), NameOffset(0),
             MangledNameOffset(0), OrigLowPc(UINT64_MAX), OrigHighPc(0),
             PCOffset(0), HasLowPc(false), IsDeclaration(false) {}
     };
 
     /// Helper for cloneDIE.
     unsigned cloneAttribute(DIE &Die,
-                            const DWARFDebugInfoEntryMinimal &InputDIE,
+                            const DWARFDie &InputDIE,
                             CompileUnit &U, const DWARFFormValue &Val,
                             const AttributeSpec AttrSpec, unsigned AttrSize,
                             AttributesInfo &AttrInfo);
 
     /// Clone a string attribute described by \p AttrSpec and add
     /// it to \p Die.
     /// \returns the size of the new attribute.
     unsigned cloneStringAttribute(DIE &Die, AttributeSpec AttrSpec,
                                   const DWARFFormValue &Val,
                                   const DWARFUnit &U);
 
     /// Clone an attribute referencing another DIE and add
     /// it to \p Die.
     /// \returns the size of the new attribute.
     unsigned
     cloneDieReferenceAttribute(DIE &Die,
-                               const DWARFDebugInfoEntryMinimal &InputDIE,
+                               const DWARFDie &InputDIE,
                                AttributeSpec AttrSpec, unsigned AttrSize,
                                const DWARFFormValue &Val, CompileUnit &Unit);
 
     /// Clone an attribute referencing another DIE and add
     /// it to \p Die.
     /// \returns the size of the new attribute.
     unsigned cloneBlockAttribute(DIE &Die, AttributeSpec AttrSpec,
                                  const DWARFFormValue &Val, unsigned AttrSize);
 
     /// Clone an attribute referencing another DIE and add
     /// it to \p Die.
     /// \returns the size of the new attribute.
     unsigned cloneAddressAttribute(DIE &Die, AttributeSpec AttrSpec,
                                    const DWARFFormValue &Val,
                                    const CompileUnit &Unit,
                                    AttributesInfo &Info);
 
     /// Clone a scalar attribute  and add it to \p Die.
     /// \returns the size of the new attribute.
     unsigned cloneScalarAttribute(DIE &Die,
-                                  const DWARFDebugInfoEntryMinimal &InputDIE,
+                                  const DWARFDie &InputDIE,
                                   CompileUnit &U, AttributeSpec AttrSpec,
                                   const DWARFFormValue &Val, unsigned AttrSize,
                                   AttributesInfo &Info);
 
     /// Get the potential name and mangled name for the entity
     /// described by \p Die and store them in \Info if they are not
     /// already there.
     /// \returns is a name was found.
-    bool getDIENames(const DWARFDebugInfoEntryMinimal &Die, DWARFUnit &U,
-                     AttributesInfo &Info);
+    bool getDIENames(const DWARFDie &Die, AttributesInfo &Info);
 
     /// Create a copy of abbreviation Abbrev.
     void copyAbbrev(const DWARFAbbreviationDeclaration &Abbrev, bool hasODR);
   };
 
   /// \brief Assign an abbreviation number to \p Abbrev
   void AssignAbbrev(DIEAbbrev &Abbrev);
 
auto CU =
                        });
   return CU != Units.end() ? CU->get() : nullptr;
 }
 
 /// Resolve the DIE attribute reference that has been
 /// extracted in \p RefValue. The resulting DIE migh be in another
 /// CompileUnit which is stored into \p ReferencedCU.
 /// \returns null if resolving fails for any reason.
-static const DWARFDebugInfoEntryMinimal *resolveDIEReference(
+static DWARFDie resolveDIEReference(
     const DwarfLinker &Linker, std::vector<std::unique_ptr<CompileUnit>> &Units,
     const DWARFFormValue &RefValue, const DWARFUnit &Unit,
-    const DWARFDebugInfoEntryMinimal &DIE, CompileUnit *&RefCU) {
+    const DWARFDie &DIE, CompileUnit *&RefCU) {
   assert(RefValue.isFormClass(DWARFFormValue::FC_Reference));
   uint64_t RefOffset = *RefValue.getAsReference();
 
   if ((RefCU = getUnitForOffset(Units, RefOffset)))
-    if (const auto *RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset))
+    if (const auto RefDie = RefCU->getOrigUnit().getDIEForOffset(RefOffset))
       return RefDie;
 
-  Linker.reportWarning("could not find referenced DIE", &Unit, &DIE);
-  return nullptr;
+  Linker.reportWarning("could not find referenced DIE", &DIE);
+  return DWARFDie();
 }
 
 /// \returns whether the passed \a Attr type might contain a DIE
 /// reference suitable for ODR uniquing.
 static bool isODRAttribute(uint16_t Attr) {
   switch (Attr) {
   default:
     return false;

 /// Some of this is mitigated byt using mangled names that do contain
 /// the arguments types, but sometimes (eg. with function templates)
 /// we don't have that. In that case, just do not unique anything that
 /// refers to the contexts we are not able to distinguish.
 ///
 /// If a context that is not a namespace appears twice in the same CU,
 /// we know it is ambiguous. Make it invalid.
 bool DeclContext::setLastSeenDIE(CompileUnit &U,
-                                 const DWARFDebugInfoEntryMinimal *Die) {
+                                 const  DWARFDie &Die) {
   if (LastSeenCompileUnitID == U.getUniqueID()) {
     DWARFUnit &OrigUnit = U.getOrigUnit();
     uint32_t FirstIdx = OrigUnit.getDIEIndex(LastSeenDIE);
     U.getInfo(FirstIdx).Ctxt = nullptr;
     return false;
   }
 
   LastSeenCompileUnitID = U.getUniqueID();
   LastSeenDIE = Die;
   return true;
 }
 
 PointerIntPair<DeclContext *, 1> DeclContextTree::getChildDeclContext(
-    DeclContext &Context, const DWARFDebugInfoEntryMinimal *DIE, CompileUnit &U,
+    DeclContext &Context, const DWARFDie &DIE, CompileUnit &U,
     NonRelocatableStringpool &StringPool, bool InClangModule) {
-  unsigned Tag = DIE->getTag();
+  unsigned Tag = DIE.getTag();
 
   // FIXME: dsymutil-classic compat: We should bail out here if we
   // have a specification or an abstract_origin. We will get the
   // parent context wrong here.
 
   switch (Tag) {
   default:
     // By default stop gathering child contexts.
     return PointerIntPair<DeclContext *, 1>(nullptr);
   case dwarf::DW_TAG_module:
     break;
   case dwarf::DW_TAG_compile_unit:
     return PointerIntPair<DeclContext *, 1>(&Context);
   case dwarf::DW_TAG_subprogram:
     // Do not unique anything inside CU local functions.
     if ((Context.getTag() == dwarf::DW_TAG_namespace ||
          Context.getTag() == dwarf::DW_TAG_compile_unit) &&
-        !DIE->getAttributeValueAsUnsignedConstant(&U.getOrigUnit(),
-                                                  dwarf::DW_AT_external, 0))
+        !DIE.getAttributeValueAsUnsignedConstant(dwarf::DW_AT_external, 0))
       return PointerIntPair<DeclContext *, 1>(nullptr);
     LLVM_FALLTHROUGH;
   case dwarf::DW_TAG_member:
   case dwarf::DW_TAG_namespace:
   case dwarf::DW_TAG_structure_type:
   case dwarf::DW_TAG_class_type:
   case dwarf::DW_TAG_union_type:
   case dwarf::DW_TAG_enumeration_type:
   case dwarf::DW_TAG_typedef:
     // Artificial things might be ambiguous, because they might be
     // created on demand. For example implicitely defined constructors
     // are ambiguous because of the way we identify contexts, and they
     // won't be generated everytime everywhere.
-    if (DIE->getAttributeValueAsUnsignedConstant(&U.getOrigUnit(),
-                                                 dwarf::DW_AT_artificial, 0))
+    if (DIE.getAttributeValueAsUnsignedConstant(dwarf::DW_AT_artificial, 0))
       return PointerIntPair<DeclContext *, 1>(nullptr);
     break;
   }
 
-  const char *Name = DIE->getName(&U.getOrigUnit(), DINameKind::LinkageName);
-  const char *ShortName = DIE->getName(&U.getOrigUnit(), DINameKind::ShortName);
+  const char *Name = DIE.getName(DINameKind::LinkageName);
+  const char *ShortName = DIE.getName(DINameKind::ShortName);
   StringRef NameRef;
   StringRef ShortNameRef;
   StringRef FileRef;
 
   if (Name)
     NameRef = StringPool.internString(Name);
   else if (Tag == dwarf::DW_TAG_namespace)
     // FIXME: For dsymutil-classic compatibility. I think uniquing
PointerIntPair<DeclContext *, 1> DeclContextTree::getChildDeclContext(
   if (!InClangModule) {
     // Gather some discriminating data about the DeclContext we will be
     // creating: File, line number and byte size. This shouldn't be
     // necessary, because the ODR is just about names, but given that we
     // do some approximations with overloaded functions and anonymous
     // namespaces, use these additional data points to make the process
     // safer.  This is disabled for clang modules, because forward
     // declarations of module-defined types do not have a file and line.
-    ByteSize = DIE->getAttributeValueAsUnsignedConstant(
-        &U.getOrigUnit(), dwarf::DW_AT_byte_size, UINT64_MAX);
+    ByteSize = DIE.getAttributeValueAsUnsignedConstant(
+        dwarf::DW_AT_byte_size, UINT64_MAX);
     if (Tag != dwarf::DW_TAG_namespace || !Name) {
-      if (unsigned FileNum = DIE->getAttributeValueAsUnsignedConstant(
-              &U.getOrigUnit(), dwarf::DW_AT_decl_file, 0)) {
+      if (unsigned FileNum = DIE.getAttributeValueAsUnsignedConstant(
+              dwarf::DW_AT_decl_file, 0)) {
         if (const auto *LT = U.getOrigUnit().getContext().getLineTableForUnit(
                 &U.getOrigUnit())) {
           // FIXME: dsymutil-classic compatibility. I'd rather not
           // unique anything in anonymous namespaces, but if we do, then
           // verify that the file and line correspond.
           if (!Name && Tag == dwarf::DW_TAG_namespace)
             FileNum = 1;
 
           // FIXME: Passing U.getOrigUnit().getCompilationDir()
           // instead of "" would allow more uniquing, but for now, do
           // it this way to match dsymutil-classic.
           if (LT->hasFileAtIndex(FileNum)) {
-            Line = DIE->getAttributeValueAsUnsignedConstant(
-                &U.getOrigUnit(), dwarf::DW_AT_decl_line, 0);
+            Line = DIE.getAttributeValueAsUnsignedConstant(
+                dwarf::DW_AT_decl_line, 0);
             // Cache the resolved paths, because calling realpath is expansive.
             StringRef ResolvedPath = U.getResolvedPath(FileNum);
             if (!ResolvedPath.empty()) {
               FileRef = ResolvedPath;
             } else {
               std::string File;
               bool gotFileName =
                 LT->getFileNameByIndex(FileNum, "",
if ((Tag == dwarf::DW_TAG_subprogram &&
        Context.getTag() != dwarf::DW_TAG_structure_type &&
        Context.getTag() != dwarf::DW_TAG_class_type) ||
       (Tag == dwarf::DW_TAG_union_type))
     return PointerIntPair<DeclContext *, 1>(*ContextIter, /* Invalid= */ 1);
 
   return PointerIntPair<DeclContext *, 1>(*ContextIter);
 }
 
-bool DwarfLinker::DIECloner::getDIENames(const DWARFDebugInfoEntryMinimal &Die,
-                                         DWARFUnit &U, AttributesInfo &Info) {
+bool DwarfLinker::DIECloner::getDIENames(const DWARFDie &Die,
+                                         AttributesInfo &Info) {
   // FIXME: a bit wasteful as the first getName might return the
   // short name.
   if (!Info.MangledName &&
-      (Info.MangledName = Die.getName(&U, DINameKind::LinkageName)))
+      (Info.MangledName = Die.getName(DINameKind::LinkageName)))
     Info.MangledNameOffset =
         Linker.StringPool.getStringOffset(Info.MangledName);
 
-  if (!Info.Name && (Info.Name = Die.getName(&U, DINameKind::ShortName)))
+  if (!Info.Name && (Info.Name = Die.getName(DINameKind::ShortName)))
     Info.NameOffset = Linker.StringPool.getStringOffset(Info.Name);
 
   return Info.Name || Info.MangledName;
 }
 
 /// \brief Report a warning to the user, optionaly including
 /// information about a specific \p DIE related to the warning.
-void DwarfLinker::reportWarning(const Twine &Warning, const DWARFUnit *Unit,
-                                const DWARFDebugInfoEntryMinimal *DIE) const {
+void DwarfLinker::reportWarning(const Twine &Warning,
+                                const DWARFDie *DIE) const {
   StringRef Context = "<debug map>";
   if (CurrentDebugObject)
     Context = CurrentDebugObject->getObjectFilename();
   warn(Warning, Context);
 
   if (!Options.Verbose || !DIE)
     return;
 
   errs() << "    in DIE:\n";
-  DIE->dump(errs(), const_cast<DWARFUnit *>(Unit), 0 /* RecurseDepth */,
-            6 /* Indent */);
+  DIE->dump(errs(), 0 /* RecurseDepth */, 6 /* Indent */);
 }
 
 bool DwarfLinker::createStreamer(const Triple &TheTriple,
                                  StringRef OutputFilename) {
   if (Options.NoOutput)
     return true;
 
   Streamer = llvm::make_unique<DwarfStreamer>();
   return Streamer->init(TheTriple, OutputFilename);
 }
 
 /// Recursive helper to build the global DeclContext information and
 /// gather the child->parent relationships in the original compile unit.
 ///
 /// \return true when this DIE and all of its children are only
 /// forward declarations to types defined in external clang modules
 /// (i.e., forward declarations that are children of a DW_TAG_module).
-static bool analyzeContextInfo(const DWARFDebugInfoEntryMinimal *DIE,
+static bool analyzeContextInfo(const DWARFDie &DIE,
                                unsigned ParentIdx, CompileUnit &CU,
                                DeclContext *CurrentDeclContext,
                                NonRelocatableStringpool &StringPool,
                                DeclContextTree &Contexts,
                                bool InImportedModule = false) {
   unsigned MyIdx = CU.getOrigUnit().getDIEIndex(DIE);
   CompileUnit::DIEInfo &Info = CU.getInfo(MyIdx);
 
   // Clang imposes an ODR on modules(!) regardless of the language:
   //  "The module-id should consist of only a single identifier,
   //   which provides the name of the module being defined. Each
   //   module shall have a single definition."
   //
   // This does not extend to the types inside the modules:
   //  "[I]n C, this implies that if two structs are defined in
   //   different submodules with the same name, those two types are
   //   distinct types (but may be compatible types if their
   //   definitions match)."
   //
   // We treat non-C++ modules like namespaces for this reason.
-  if (DIE->getTag() == dwarf::DW_TAG_module && ParentIdx == 0 &&
-      DIE->getAttributeValueAsString(&CU.getOrigUnit(), dwarf::DW_AT_name,
-                                     "") != CU.getClangModuleName()) {
+  if (DIE.getTag() == dwarf::DW_TAG_module && ParentIdx == 0 &&
+      DIE.getAttributeValueAsString(dwarf::DW_AT_name,
     InImportedModule = true;
   }
 
   Info.ParentIdx = ParentIdx;
   bool InClangModule = CU.isClangModule() || InImportedModule;
   if (CU.hasODR() || InClangModule) {
     if (CurrentDeclContext) {
       auto PtrInvalidPair = Contexts.getChildDeclContext(
           *CurrentDeclContext, DIE, CU, StringPool, InClangModule);
       CurrentDeclContext = PtrInvalidPair.getPointer();
       Info.Ctxt =
           PtrInvalidPair.getInt() ? nullptr : PtrInvalidPair.getPointer();
     } else
       Info.Ctxt = CurrentDeclContext = nullptr;
   }
 
   Info.Prune = InImportedModule;
-  if (DIE->hasChildren())
-    for (auto *Child = DIE->getFirstChild(); Child && !Child->isNULL();
-         Child = Child->getSibling())
+  if (DIE.hasChildren())
+    for (auto Child = DIE.getFirstChild(); Child && !Child.isNULL();
+         Child = Child.getSibling())
       Info.Prune &= analyzeContextInfo(Child, MyIdx, CU, CurrentDeclContext,
                                        StringPool, Contexts, InImportedModule);
 
   // Prune this DIE if it is either a forward declaration inside a
   // DW_TAG_module or a DW_TAG_module that contains nothing but
   // forward declarations.
-  Info.Prune &= (DIE->getTag() == dwarf::DW_TAG_module) ||
-                DIE->getAttributeValueAsUnsignedConstant(
-                    &CU.getOrigUnit(), dwarf::DW_AT_declaration, 0);
+  Info.Prune &= (DIE.getTag() == dwarf::DW_TAG_module) ||
+                DIE.getAttributeValueAsUnsignedConstant(
+                    dwarf::DW_AT_declaration, 0);
 
   // Don't prune it if there is no definition for the DIE.
   Info.Prune &= Info.Ctxt && Info.Ctxt->getCanonicalDIEOffset();
 
   return Info.Prune;
 }
 
 static bool dieNeedsChildrenToBeMeaningful(uint32_t Tag) {
getAttributeOffsets(const DWARFAbbreviationDeclaration *Abbrev, unsigned Idx,
   DWARFFormValue::skipValue(Abbrev->getFormByIndex(Idx), Data, &End, &Unit);
 
   return std::make_pair(Offset, End);
 }
 
 /// \brief Check if a variable describing DIE should be kept.
 /// \returns updated TraversalFlags.
 unsigned DwarfLinker::shouldKeepVariableDIE(RelocationManager &RelocMgr,
-                                            const DWARFDebugInfoEntryMinimal &DIE,
+                                            const DWARFDie &DIE,
                                             CompileUnit &Unit,
                                             CompileUnit::DIEInfo &MyInfo,
                                             unsigned Flags) {
   const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
 
   // Global variables with constant value can always be kept.
   if (!(Flags & TF_InFunctionScope) &&
       Abbrev->findAttributeIndex(dwarf::DW_AT_const_value)) {
unsigned DwarfLinker::shouldKeepVariableDIE(RelocationManager &RelocMgr,
   // always check in the variable has a valid relocation, so that the
   // DIEInfo is filled. However, we don't want a static variable in a
   // function to force us to keep the enclosing function.
   if (!RelocMgr.hasValidRelocation(LocationOffset, LocationEndOffset, MyInfo) ||
       (Flags & TF_InFunctionScope))
     return Flags;
 
   if (Options.Verbose)
-    DIE.dump(outs(), const_cast<DWARFUnit *>(&OrigUnit), 0, 8 /* Indent */);
+    DIE.dump(outs(), 0, 8 /* Indent */);
 
   return Flags | TF_Keep;
 }
 
 /// \brief Check if a function describing DIE should be kept.
 /// \returns updated TraversalFlags.
 unsigned DwarfLinker::shouldKeepSubprogramDIE(
     RelocationManager &RelocMgr,
-    const DWARFDebugInfoEntryMinimal &DIE, CompileUnit &Unit,
+    const DWARFDie &DIE, CompileUnit &Unit,
     CompileUnit::DIEInfo &MyInfo, unsigned Flags) {
   const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
 
   Flags |= TF_InFunctionScope;
 
   Optional<uint32_t> LowPcIdx = Abbrev->findAttributeIndex(dwarf::DW_AT_low_pc);
   if (!LowPcIdx)
     return Flags;
 
   uint32_t Offset = DIE.getOffset() + getULEB128Size(Abbrev->getCode());
   const DWARFUnit &OrigUnit = Unit.getOrigUnit();
   uint32_t LowPcOffset, LowPcEndOffset;
   std::tie(LowPcOffset, LowPcEndOffset) =
       getAttributeOffsets(Abbrev, *LowPcIdx, Offset, OrigUnit);
 
   uint64_t LowPc =
-      DIE.getAttributeValueAsAddress(&OrigUnit, dwarf::DW_AT_low_pc, -1ULL);
+      DIE.getAttributeValueAsAddress(dwarf::DW_AT_low_pc, -1ULL);
   assert(LowPc != -1ULL && "low_pc attribute is not an address.");
   if (LowPc == -1ULL ||
       !RelocMgr.hasValidRelocation(LowPcOffset, LowPcEndOffset, MyInfo))
     return Flags;
 
   if (Options.Verbose)
-    DIE.dump(outs(), const_cast<DWARFUnit *>(&OrigUnit), 0, 8 /* Indent */);
+    DIE.dump(outs(), 0, 8 /* Indent */);
 
   Flags |= TF_Keep;
 
   DWARFFormValue HighPcValue;
-  if (!DIE.getAttributeValue(&OrigUnit, dwarf::DW_AT_high_pc, HighPcValue)) {
+  if (!DIE.getAttributeValue(dwarf::DW_AT_high_pc, HighPcValue)) {
     reportWarning("Function without high_pc. Range will be discarded.\n",
-                  &OrigUnit, &DIE);
+                  &DIE);
     return Flags;
   }
 
   uint64_t HighPc;
   if (HighPcValue.isFormClass(DWARFFormValue::FC_Address)) {
     HighPc = *HighPcValue.getAsAddress();
   } else {
     assert(HighPcValue.isFormClass(DWARFFormValue::FC_Constant));
     HighPc = LowPc + *HighPcValue.getAsUnsignedConstant();
   }
 
   // Replace the debug map range with a more accurate one.
   Ranges[LowPc] = std::make_pair(HighPc, MyInfo.AddrAdjust);
   Unit.addFunctionRange(LowPc, HighPc, MyInfo.AddrAdjust);
   return Flags;
 }
 
 /// \brief Check if a DIE should be kept.
 /// \returns updated TraversalFlags.
 unsigned DwarfLinker::shouldKeepDIE(RelocationManager &RelocMgr,
-                                    const DWARFDebugInfoEntryMinimal &DIE,
+                                    const DWARFDie &DIE,
                                     CompileUnit &Unit,
                                     CompileUnit::DIEInfo &MyInfo,
                                     unsigned Flags) {
   switch (DIE.getTag()) {
   case dwarf::DW_TAG_constant:
   case dwarf::DW_TAG_variable:
     return shouldKeepVariableDIE(RelocMgr, DIE, Unit, MyInfo, Flags);
   case dwarf::DW_TAG_subprogram:

 /// as kept.
 ///
 /// This function is called by lookForDIEsToKeep on DIEs that are
 /// newly discovered to be needed in the link. It recursively calls
 /// back to lookForDIEsToKeep while adding TF_DependencyWalk to the
 /// TraversalFlags to inform it that it's not doing the primary DIE
 /// tree walk.
 void DwarfLinker::keepDIEAndDependencies(RelocationManager &RelocMgr,
-                                          const DWARFDebugInfoEntryMinimal &Die,
+                                          const DWARFDie &Die,
                                           CompileUnit::DIEInfo &MyInfo,
                                           const DebugMapObject &DMO,
                                           CompileUnit &CU, bool UseODR) {
-  const DWARFUnit &Unit = CU.getOrigUnit();
+  DWARFUnit &Unit = CU.getOrigUnit();
   MyInfo.Keep = true;
 
   // First mark all the parent chain as kept.
   unsigned AncestorIdx = MyInfo.ParentIdx;
   while (!CU.getInfo(AncestorIdx).Keep) {
     unsigned ODRFlag = UseODR ? TF_ODR : 0;
-    lookForDIEsToKeep(RelocMgr, *Unit.getDIEAtIndex(AncestorIdx), DMO, CU,
+    lookForDIEsToKeep(RelocMgr, Unit.getDIEAtIndex(AncestorIdx), DMO, CU,
                       TF_ParentWalk | TF_Keep | TF_DependencyWalk | ODRFlag);
     AncestorIdx = CU.getInfo(AncestorIdx).ParentIdx;
   }
 
   // Then we need to mark all the DIEs referenced by this DIE's
   // attributes as kept.
   DataExtractor Data = Unit.getDebugInfoExtractor();
   const auto *Abbrev = Die.getAbbreviationDeclarationPtr();
   uint32_t Offset = Die.getOffset() + getULEB128Size(Abbrev->getCode());
 
   // Mark all DIEs referenced through atttributes as kept.
   for (const auto &AttrSpec : Abbrev->attributes()) {
     DWARFFormValue Val(AttrSpec.Form);
 
     if (!Val.isFormClass(DWARFFormValue::FC_Reference)) {
       DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset, &Unit);
       continue;
     }
 
     Val.extractValue(Data, &Offset, &Unit);
     CompileUnit *ReferencedCU;
-    if (const auto *RefDIE =
+    if (auto RefDIE =
             resolveDIEReference(*this, Units, Val, Unit, Die, ReferencedCU)) {
       uint32_t RefIdx = ReferencedCU->getOrigUnit().getDIEIndex(RefDIE);
       CompileUnit::DIEInfo &Info = ReferencedCU->getInfo(RefIdx);
       // If the referenced DIE has a DeclContext that has already been
       // emitted, then do not keep the one in this CU. We'll link to
       // the canonical DIE in cloneDieReferenceAttribute.
       // FIXME: compatibility with dsymutil-classic. UseODR shouldn't
       // be necessary and could be advantageously replaced by
       // ReferencedCU->hasODR() && CU.hasODR().
       // FIXME: compatibility with dsymutil-classic. There is no
       // reason not to unique ref_addr references.
       if (AttrSpec.Form != dwarf::DW_FORM_ref_addr && UseODR && Info.Ctxt &&
           Info.Ctxt != ReferencedCU->getInfo(Info.ParentIdx).Ctxt &&
           Info.Ctxt->getCanonicalDIEOffset() && isODRAttribute(AttrSpec.Attr))
         continue;
 
       // Keep a module forward declaration if there is no definition.
       if (!(isODRAttribute(AttrSpec.Attr) && Info.Ctxt &&
             Info.Ctxt->getCanonicalDIEOffset()))
         Info.Prune = false;
 
       unsigned ODRFlag = UseODR ? TF_ODR : 0;
-      lookForDIEsToKeep(RelocMgr, *RefDIE, DMO, *ReferencedCU,
+      lookForDIEsToKeep(RelocMgr, RefDIE, DMO, *ReferencedCU,
                         TF_Keep | TF_DependencyWalk | ODRFlag);
     }
   }
 }
 
 /// \brief Recursively walk the \p DIE tree and look for DIEs to
 /// keep. Store that information in \p CU's DIEInfo.
 ///
 /// This function is the entry point of the DIE selection
 /// algorithm. It is expected to walk the DIE tree in file order and
 /// (though the mediation of its helper) call hasValidRelocation() on
 /// each DIE that might be a 'root DIE' (See DwarfLinker class
 /// comment).
 /// While walking the dependencies of root DIEs, this function is
 /// also called, but during these dependency walks the file order is
 /// not respected. The TF_DependencyWalk flag tells us which kind of
 /// traversal we are currently doing.
 void DwarfLinker::lookForDIEsToKeep(RelocationManager &RelocMgr,
-                                    const DWARFDebugInfoEntryMinimal &Die,
+                                    const DWARFDie &Die,
                                     const DebugMapObject &DMO, CompileUnit &CU,
                                     unsigned Flags) {
-  unsigned Idx = CU.getOrigUnit().getDIEIndex(&Die);
+  unsigned Idx = CU.getOrigUnit().getDIEIndex(Die);
   CompileUnit::DIEInfo &MyInfo = CU.getInfo(Idx);
   bool AlreadyKept = MyInfo.Keep;
   if (MyInfo.Prune)
     return;
 
   // If the Keep flag is set, we are marking a required DIE's
   // dependencies. If our target is already marked as kept, we're all
   // set.
void DwarfLinker::lookForDIEsToKeep(RelocationManager &RelocMgr,
   // set of DIE types for which we want to ignore that directive and still
   // walk their children.
   if (dieNeedsChildrenToBeMeaningful(Die.getTag()))
     Flags &= ~TF_ParentWalk;
 
   if (!Die.hasChildren() || (Flags & TF_ParentWalk))
     return;
 
-  for (auto *Child = Die.getFirstChild(); Child && !Child->isNULL();
-       Child = Child->getSibling())
-    lookForDIEsToKeep(RelocMgr, *Child, DMO, CU, Flags);
+  for (auto Child = Die.getFirstChild(); Child && !Child.isNULL();
+       Child = Child.getSibling())
+    lookForDIEsToKeep(RelocMgr, Child, DMO, CU, Flags);
 }
 
 /// \brief Assign an abbreviation numer to \p Abbrev.
 ///
 /// Our DIEs get freed after every DebugMapObject has been processed,
 /// thus the FoldingSet we use to unique DIEAbbrevs cannot refer to
 /// the instances hold by the DIEs. When we encounter an abbreviation
 /// that we don't know, we create a permanent copy of it.
unsigned DwarfLinker::DIECloner::cloneStringAttribute(DIE &Die,
   const char *String = *Val.getAsCString();
   unsigned Offset = Linker.StringPool.getStringOffset(String);
   Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr), dwarf::DW_FORM_strp,
                DIEInteger(Offset));
   return 4;
 }
 
 unsigned DwarfLinker::DIECloner::cloneDieReferenceAttribute(
-    DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE,
+    DIE &Die, const DWARFDie &InputDIE,
     AttributeSpec AttrSpec, unsigned AttrSize, const DWARFFormValue &Val,
     CompileUnit &Unit) {
   const DWARFUnit &U = Unit.getOrigUnit();
   uint32_t Ref = *Val.getAsReference();
   DIE *NewRefDie = nullptr;
   CompileUnit *RefUnit = nullptr;
   DeclContext *Ctxt = nullptr;
 
-  const DWARFDebugInfoEntryMinimal *RefDie =
-      resolveDIEReference(Linker, CompileUnits, Val, U, InputDIE, RefUnit);
+  DWARFDie RefDie = resolveDIEReference(Linker, CompileUnits, Val, U, InputDIE,
+                                        RefUnit);
 
   // If the referenced DIE is not found,  drop the attribute.
   if (!RefDie)
     return 0;
 
   unsigned Idx = RefUnit->getOrigUnit().getDIEIndex(RefDie);
   CompileUnit::DIEInfo &RefInfo = RefUnit->getInfo(Idx);
 
   // If we already have emitted an equivalent DeclContext, just point
   // at it.
   if (isODRAttribute(AttrSpec.Attr)) {
     Ctxt = RefInfo.Ctxt;
     if (Ctxt && Ctxt->getCanonicalDIEOffset()) {
       DIEInteger Attr(Ctxt->getCanonicalDIEOffset());
       Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
                    dwarf::DW_FORM_ref_addr, Attr);
       return U.getRefAddrByteSize();
     }
   }
 
   if (!RefInfo.Clone) {
     assert(Ref > InputDIE.getOffset());
     // We haven't cloned this DIE yet. Just create an empty one and
     // store it. It'll get really cloned when we process it.
-    RefInfo.Clone = DIE::get(DIEAlloc, dwarf::Tag(RefDie->getTag()));
+    RefInfo.Clone = DIE::get(DIEAlloc, dwarf::Tag(RefDie.getTag()));
   }
   NewRefDie = RefInfo.Clone;
 
   if (AttrSpec.Form == dwarf::DW_FORM_ref_addr ||
       (Unit.hasODR() && isODRAttribute(AttrSpec.Attr))) {
     // We cannot currently rely on a DIEEntry to emit ref_addr
     // references, because the implementation calls back to DwarfDebug
     // to find the unit offset. (We don't have a DwarfDebug)
unsigned DwarfLinker::DIECloner::cloneAddressAttribute(
   }
 
   Die.addValue(DIEAlloc, static_cast<dwarf::Attribute>(AttrSpec.Attr),
                static_cast<dwarf::Form>(AttrSpec.Form), DIEInteger(Addr));
   return Unit.getOrigUnit().getAddressByteSize();
 }
 
 unsigned DwarfLinker::DIECloner::cloneScalarAttribute(
-    DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &Unit,
+    DIE &Die, const DWARFDie &InputDIE, CompileUnit &Unit,
     AttributeSpec AttrSpec, const DWARFFormValue &Val, unsigned AttrSize,
     AttributesInfo &Info) {
   uint64_t Value;
   if (AttrSpec.Attr == dwarf::DW_AT_high_pc &&
       Die.getTag() == dwarf::DW_TAG_compile_unit) {
     if (Unit.getLowPc() == -1ULL)
       return 0;
     // Dwarf >= 4 high_pc is an size, not an address.
     Value = Unit.getHighPc() - Unit.getLowPc();
   } else if (AttrSpec.Form == dwarf::DW_FORM_sec_offset)
     Value = *Val.getAsSectionOffset();
   else if (AttrSpec.Form == dwarf::DW_FORM_sdata)
     Value = *Val.getAsSignedConstant();
   else if (auto OptionalValue = Val.getAsUnsignedConstant())
     Value = *OptionalValue;
   else {
     Linker.reportWarning(
         "Unsupported scalar attribute form. Dropping attribute.",
-        &Unit.getOrigUnit(), &InputDIE);
+        &InputDIE);
     return 0;
   }
   PatchLocation Patch =
       Die.addValue(DIEAlloc, dwarf::Attribute(AttrSpec.Attr),
                    dwarf::Form(AttrSpec.Form), DIEInteger(Value));
   if (AttrSpec.Attr == dwarf::DW_AT_ranges)
     Unit.noteRangeAttribute(Die, Patch);
 
   // A more generic way to check for location attributes would be
   // nice, but it's very unlikely that any other attribute needs a
   // location list.
   else if (AttrSpec.Attr == dwarf::DW_AT_location ||
            AttrSpec.Attr == dwarf::DW_AT_frame_base)
     Unit.noteLocationAttribute(Patch, Info.PCOffset);
   else if (AttrSpec.Attr == dwarf::DW_AT_declaration && Value)
     Info.IsDeclaration = true;
 
   return AttrSize;
 }
 
 /// \brief Clone \p InputDIE's attribute described by \p AttrSpec with
 /// value \p Val, and add it to \p Die.
 /// \returns the size of the cloned attribute.
 unsigned DwarfLinker::DIECloner::cloneAttribute(
-    DIE &Die, const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &Unit,
+    DIE &Die, const DWARFDie &InputDIE, CompileUnit &Unit,
     const DWARFFormValue &Val, const AttributeSpec AttrSpec, unsigned AttrSize,
     AttributesInfo &Info) {
   const DWARFUnit &U = Unit.getOrigUnit();
 
   switch (AttrSpec.Form) {
   case dwarf::DW_FORM_strp:
   case dwarf::DW_FORM_string:
     return cloneStringAttribute(Die, AttrSpec, Val, U);
unsigned DwarfLinker::DIECloner::cloneAttribute(
   case dwarf::DW_FORM_sdata:
   case dwarf::DW_FORM_sec_offset:
   case dwarf::DW_FORM_flag:
   case dwarf::DW_FORM_flag_present:
     return cloneScalarAttribute(Die, InputDIE, Unit, AttrSpec, Val, AttrSize,
                                 Info);
   default:
     Linker.reportWarning(
-        "Unsupported attribute form in cloneAttribute. Dropping.", &U,
-        &InputDIE);
+        "Unsupported attribute form in cloneAttribute. Dropping.", &InputDIE);
   }
 
   return 0;
 }
 
 /// \brief Apply the valid relocations found by findValidRelocs() to
 /// the buffer \p Data, taking into account that Data is at \p BaseOffset
 /// in the debug_info section.
case dwarf::DW_AT_frame_base:
     // no point in keeping these anyway when the function wasn't linked.
     return (SkipPC || (!InFunctionScope && Tag == dwarf::DW_TAG_variable &&
                        !InDebugMap)) &&
            !DWARFFormValue(AttrSpec.Form).isFormClass(DWARFFormValue::FC_Block);
   }
 }
 
 DIE *DwarfLinker::DIECloner::cloneDIE(
-    const DWARFDebugInfoEntryMinimal &InputDIE, CompileUnit &Unit,
+    const DWARFDie &InputDIE, CompileUnit &Unit,
     int64_t PCOffset, uint32_t OutOffset, unsigned Flags, DIE *Die) {
   DWARFUnit &U = Unit.getOrigUnit();
-  unsigned Idx = U.getDIEIndex(&InputDIE);
+  unsigned Idx = U.getDIEIndex(InputDIE);
   CompileUnit::DIEInfo &Info = Unit.getInfo(Idx);
 
   // Should the DIE appear in the output?
   if (!Unit.getInfo(Idx).Keep)
     return nullptr;
 
   uint32_t Offset = InputDIE.getOffset();
   assert(!(Die && Info.Clone) && "Can't supply a DIE and a cloned DIE");
DIE *DwarfLinker::DIECloner::cloneDIE(
 
   // Extract and clone every attribute.
   DataExtractor Data = U.getDebugInfoExtractor();
   // Point to the next DIE (generally there is always at least a NULL
   // entry after the current one). If this is a lone
   // DW_TAG_compile_unit without any children, point to the next unit.
   uint32_t NextOffset =
     (Idx + 1 < U.getNumDIEs())
-    ? U.getDIEAtIndex(Idx + 1)->getOffset()
+    ? U.getDIEAtIndex(Idx + 1).getOffset()
     : U.getNextUnitOffset();
   AttributesInfo AttrInfo;
 
   // We could copy the data only if we need to aply a relocation to
   // it. After testing, it seems there is no performance downside to
   // doing the copy unconditionally, and it makes the code simpler.
   SmallString<40> DIECopy(Data.getData().substr(Offset, NextOffset - Offset));
   Data = DataExtractor(DIECopy, Data.isLittleEndian(), Data.getAddressSize());
   // Modify the copy with relocated addresses.
   if (RelocMgr.applyValidRelocs(DIECopy, Offset, Data.isLittleEndian())) {
     // If we applied relocations, we store the value of high_pc that was
     // potentially stored in the input DIE. If high_pc is an address
     // (Dwarf version == 2), then it might have been relocated to a
     // totally unrelated value (because the end address in the object
     // file might be start address of another function which got moved
     // independantly by the linker). The computation of the actual
     // high_pc value is done in cloneAddressAttribute().
     AttrInfo.OrigHighPc =
-        InputDIE.getAttributeValueAsAddress(&U, dwarf::DW_AT_high_pc, 0);
+        InputDIE.getAttributeValueAsAddress(dwarf::DW_AT_high_pc, 0);
     // Also store the low_pc. It might get relocated in an
     // inline_subprogram that happens at the beginning of its
     // inlining function.
     AttrInfo.OrigLowPc =
-        InputDIE.getAttributeValueAsAddress(&U, dwarf::DW_AT_low_pc, UINT64_MAX);
+        InputDIE.getAttributeValueAsAddress(dwarf::DW_AT_low_pc, UINT64_MAX);
   }
 
   // Reset the Offset to 0 as we will be working on the local copy of
   // the data.
   Offset = 0;
 
   const auto *Abbrev = InputDIE.getAbbreviationDeclarationPtr();
   Offset += getULEB128Size(Abbrev->getCode());
DIE *DwarfLinker::DIECloner::cloneDIE(
 
   // Look for accelerator entries.
   uint16_t Tag = InputDIE.getTag();
   // FIXME: This is slightly wrong. An inline_subroutine without a
   // low_pc, but with AT_ranges might be interesting to get into the
   // accelerator tables too. For now stick with dsymutil's behavior.
   if ((Info.InDebugMap || AttrInfo.HasLowPc) &&
       Tag != dwarf::DW_TAG_compile_unit &&
-      getDIENames(InputDIE, Unit.getOrigUnit(), AttrInfo)) {
+      getDIENames(InputDIE, AttrInfo)) {
     if (AttrInfo.MangledName && AttrInfo.MangledName != AttrInfo.Name)
       Unit.addNameAccelerator(Die, AttrInfo.MangledName,
                               AttrInfo.MangledNameOffset,
                               Tag == dwarf::DW_TAG_inlined_subroutine);
     if (AttrInfo.Name)
       Unit.addNameAccelerator(Die, AttrInfo.Name, AttrInfo.NameOffset,
                               Tag == dwarf::DW_TAG_inlined_subroutine);
   } else if (isTypeTag(Tag) && !AttrInfo.IsDeclaration &&
-             getDIENames(InputDIE, Unit.getOrigUnit(), AttrInfo)) {
+             getDIENames(InputDIE, AttrInfo)) {
     Unit.addTypeAccelerator(Die, AttrInfo.Name, AttrInfo.NameOffset);
   }
 
   // Determine whether there are any children that we want to keep.
   bool HasChildren = false;
-  for (auto *Child = InputDIE.getFirstChild(); Child && !Child->isNULL();
-       Child = Child->getSibling()) {
+  for (auto Child = InputDIE.getFirstChild(); Child && !Child.isNULL();
+       Child = Child.getSibling()) {
     unsigned Idx = U.getDIEIndex(Child);
     if (Unit.getInfo(Idx).Keep) {
       HasChildren = true;
       break;
     }
   }
 
   DIEAbbrev NewAbbrev = Die->generateAbbrev();
   if (HasChildren)
     NewAbbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes);
   // Assign a permanent abbrev number
   Linker.AssignAbbrev(NewAbbrev);
   Die->setAbbrevNumber(NewAbbrev.getNumber());
 
   // Add the size of the abbreviation number to the output offset.
   OutOffset += getULEB128Size(Die->getAbbrevNumber());
 
   if (!HasChildren) {
     // Update our size.
     Die->setSize(OutOffset - Die->getOffset());
     return Die;
   }
 
   // Recursively clone children.
-  for (auto *Child = InputDIE.getFirstChild(); Child && !Child->isNULL();
-       Child = Child->getSibling()) {
-    if (DIE *Clone = cloneDIE(*Child, Unit, PCOffset, OutOffset, Flags)) {
+  for (auto Child = InputDIE.getFirstChild(); Child && !Child.isNULL();
+       Child = Child.getSibling()) {
+    if (DIE *Clone = cloneDIE(Child, Unit, PCOffset, OutOffset, Flags)) {
       Die->addChild(Clone);
       OutOffset = Clone->getOffset() + Clone->getSize();
     }
   }
 
   // Account for the end of children marker.
   OutOffset += sizeof(int8_t);
   // Update our size.
   Die->setSize(OutOffset - Die->getOffset());
   return Die;
 }
 
 /// \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();
   DataExtractor RangeExtractor(OrigDwarf.getRangeSection(),
                                OrigDwarf.isLittleEndian(), AddressSize);
   auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange;
   DWARFUnit &OrigUnit = Unit.getOrigUnit();
-  const auto *OrigUnitDie = OrigUnit.getUnitDIE(false);
-  uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress(
-      &OrigUnit, dwarf::DW_AT_low_pc, -1ULL);
+  auto OrigUnitDie = OrigUnit.getUnitDIE(false);
+  uint64_t OrigLowPc = OrigUnitDie.getAttributeValueAsAddress(
+      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;
   if (OrigLowPc != -1ULL)
     UnitPcOffset = int64_t(OrigLowPc) - Unit.getLowPc();
 
   for (const auto &RangeAttribute : Unit.getRangesAttributes()) {
     uint32_t Offset = RangeAttribute.get();
static void patchStmtList(DIE &Die, DIEInteger Offset) {
   llvm_unreachable("Didn't find DW_AT_stmt_list in cloned DIE!");
 }
 
 /// \brief Extract the line table for \p Unit from \p OrigDwarf, and
 /// recreate a relocated version of these for the address ranges that
 /// are present in the binary.
 void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
                                         DWARFContext &OrigDwarf) {
-  const DWARFDebugInfoEntryMinimal *CUDie = Unit.getOrigUnit().getUnitDIE();
-  uint64_t StmtList = CUDie->getAttributeValueAsSectionOffset(
-      &Unit.getOrigUnit(), dwarf::DW_AT_stmt_list, -1ULL);
+  DWARFDie CUDie = Unit.getOrigUnit().getUnitDIE();
+  uint64_t StmtList = CUDie.getAttributeValueAsSectionOffset(
+      dwarf::DW_AT_stmt_list, -1ULL);
   if (StmtList == -1ULL)
     return;
 
   // 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.
for (const auto &Attr : Abbrev.attributes()) {
     if (hasODR && isODRAttribute(Attr.Attr))
       Form = dwarf::DW_FORM_ref_addr;
     Copy.AddAttribute(dwarf::Attribute(Attr.Attr), dwarf::Form(Form));
   }
 
   Linker.AssignAbbrev(Copy);
 }
 
-static uint64_t getDwoId(const DWARFDebugInfoEntryMinimal &CUDie,
+static uint64_t getDwoId(const DWARFDie &CUDie,
                          const DWARFUnit &Unit) {
   uint64_t DwoId =
-      CUDie.getAttributeValueAsUnsignedConstant(&Unit, dwarf::DW_AT_dwo_id, 0);
+      CUDie.getAttributeValueAsUnsignedConstant(dwarf::DW_AT_dwo_id, 0);
   if (!DwoId)
-    DwoId = CUDie.getAttributeValueAsUnsignedConstant(&Unit,
-                                                      dwarf::DW_AT_GNU_dwo_id, 0);
+    DwoId = CUDie.getAttributeValueAsUnsignedConstant(dwarf::DW_AT_GNU_dwo_id,
+                                                      0);
   return DwoId;
 }
 
 bool DwarfLinker::registerModuleReference(
-    const DWARFDebugInfoEntryMinimal &CUDie, const DWARFUnit &Unit,
+    const DWARFDie &CUDie, const DWARFUnit &Unit,
     DebugMap &ModuleMap, unsigned Indent) {
   std::string PCMfile =
-      CUDie.getAttributeValueAsString(&Unit, dwarf::DW_AT_dwo_name, "");
+      CUDie.getAttributeValueAsString(dwarf::DW_AT_dwo_name, "");
   if (PCMfile.empty())
     PCMfile =
-        CUDie.getAttributeValueAsString(&Unit, dwarf::DW_AT_GNU_dwo_name, "");
+        CUDie.getAttributeValueAsString(dwarf::DW_AT_GNU_dwo_name, "");
   if (PCMfile.empty())
     return false;
 
   // Clang module DWARF skeleton CUs abuse this for the path to the module.
   std::string PCMpath =
-      CUDie.getAttributeValueAsString(&Unit, dwarf::DW_AT_comp_dir, "");
+      CUDie.getAttributeValueAsString(dwarf::DW_AT_comp_dir, "");
   uint64_t DwoId = getDwoId(CUDie, Unit);
 
   std::string Name =
-      CUDie.getAttributeValueAsString(&Unit, dwarf::DW_AT_name, "");
+      CUDie.getAttributeValueAsString(dwarf::DW_AT_name, "");
   if (Name.empty()) {
     reportWarning("Anonymous module skeleton CU for " + PCMfile);
     return true;
   }
 
   if (Options.Verbose) {
     outs().indent(Indent);
     outs() << "Found clang module reference " << PCMfile;
void DwarfLinker::loadClangModule(StringRef Filename, StringRef ModulePath,
   }
 
   std::unique_ptr<CompileUnit> Unit;
 
   // Setup access to the debug info.
   DWARFContextInMemory DwarfContext(*ErrOrObj);
   RelocationManager RelocMgr(*this);
   for (const auto &CU : DwarfContext.compile_units()) {
-    auto *CUDie = CU->getUnitDIE(false);
+    auto CUDie = CU->getUnitDIE(false);
     // Recursively get all modules imported by this one.
-    if (!registerModuleReference(*CUDie, *CU, ModuleMap, Indent)) {
+    if (!registerModuleReference(CUDie, *CU, ModuleMap, Indent)) {
       if (Unit) {
         errs() << Filename << ": Clang modules are expected to have exactly"
                << " 1 compile unit.\n";
         exitDsymutil(1);
       }
       // FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is
       // fixed in clang, only warn about DWO_id mismatches in verbose mode.
       // ASTFileSignatures will change randomly when a module is rebuilt.
-      uint64_t PCMDwoId = getDwoId(*CUDie, *CU);
+      uint64_t PCMDwoId = getDwoId(CUDie, *CU);
       if (PCMDwoId != DwoId) {
         if (Options.Verbose)
           reportWarning(
               Twine("hash mismatch: this object file was built against a "
                     "different version of the module ") + Filename);
         // Update the cache entry with the DwoId of the module loaded from disk.
         ClangModules[Filename] = PCMDwoId;
       }

 }
 
 void DwarfLinker::DIECloner::cloneAllCompileUnits(
     DWARFContextInMemory &DwarfContext) {
   if (!Linker.Streamer)
     return;
 
   for (auto &CurrentUnit : CompileUnits) {
-    const auto *InputDIE = CurrentUnit->getOrigUnit().getUnitDIE();
+    auto InputDIE = CurrentUnit->getOrigUnit().getUnitDIE();
     CurrentUnit->setStartOffset(Linker.OutputDebugInfoSize);
     // Clonse the InputDIE into your Unit DIE in our compile unit since it
     // already has a DIE inside of it.
-    if (!cloneDIE(*InputDIE, *CurrentUnit, 0 /* PC offset */,
+    if (!cloneDIE(InputDIE, *CurrentUnit, 0 /* PC offset */,
                   11 /* Unit Header size */, 0,
                   CurrentUnit->getOutputUnitDIE()))
       continue;
     Linker.OutputDebugInfoSize = CurrentUnit->computeNextUnitOffset();
     if (Linker.Options.NoOutput)
       continue;
     // FIXME: for compatibility with the classic dsymutil, we emit
     // an empty line table for the unit, even if the unit doesn't
for (const auto &Obj : Map.objects()) {
     }
 
     // Setup access to the debug info.
     DWARFContextInMemory DwarfContext(*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()) {
-      auto *CUDie = CU->getUnitDIE(false);
+      auto CUDie = CU->getUnitDIE(false);
       if (Options.Verbose) {
         outs() << "Input compilation unit:";
-        CUDie->dump(outs(), CU.get(), 0);
+        CUDie.dump(outs(), 0);
       }
 
-      if (!registerModuleReference(*CUDie, *CU, ModuleMap))
+      if (!registerModuleReference(CUDie, *CU, ModuleMap))
         Units.push_back(llvm::make_unique<CompileUnit>(*CU, UnitID++,
                                                        !Options.NoODR, ""));
     }
 
     // Now build the DIE parent links that we will use during the next phase.
     for (auto &CurrentUnit : Units)
       analyzeContextInfo(CurrentUnit->getOrigUnit().getUnitDIE(), 0, *CurrentUnit,
                          &ODRContexts.getRoot(), StringPool, ODRContexts);
 
     // Then mark all the DIEs that need to be present in the linked
     // output and collect some information about them. Note that this
     // loop can not be merged with the previous one becaue cross-cu
     // references require the ParentIdx to be setup for every CU in
     // the object file before calling this.
     for (auto &CurrentUnit : Units)
-      lookForDIEsToKeep(RelocMgr, *CurrentUnit->getOrigUnit().getUnitDIE(), *Obj,
+      lookForDIEsToKeep(RelocMgr, CurrentUnit->getOrigUnit().getUnitDIE(), *Obj,
                         *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)

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/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
-#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
+#include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/TargetSelect.h"
 #include "gtest/gtest.h"
 #include <climits>
 
#define UDATA_1 18446744073709551614ULL
   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();
   EXPECT_EQ(NumCUs, 1u);
   DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
-  auto DiePtr = U->getUnitDIE(false);
-  EXPECT_TRUE(DiePtr != nullptr);
+  auto DieDG = U->getUnitDIE(false);
+  EXPECT_TRUE(DieDG.isValid());
 
   //----------------------------------------------------------------------
   // Test address forms
   //----------------------------------------------------------------------
-  EXPECT_EQ(DiePtr->getAttributeValueAsAddress(U, Attr_DW_FORM_addr, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsAddress(Attr_DW_FORM_addr, 0),
             AddrValue);
 
   //----------------------------------------------------------------------
   // Test block forms
   //----------------------------------------------------------------------
   DWARFFormValue FormValue;
   ArrayRef<uint8_t> ExtractedBlockData;
   Optional<ArrayRef<uint8_t>> BlockDataOpt;
 
-  EXPECT_TRUE(DiePtr->getAttributeValue(U, Attr_DW_FORM_block, FormValue));
+  EXPECT_TRUE(DieDG.getAttributeValue(Attr_DW_FORM_block, FormValue));
   BlockDataOpt = FormValue.getAsBlock();
   EXPECT_TRUE(BlockDataOpt.hasValue());
   ExtractedBlockData = BlockDataOpt.getValue();
   EXPECT_EQ(ExtractedBlockData.size(), BlockSize);
   EXPECT_TRUE(memcmp(ExtractedBlockData.data(), BlockData, BlockSize) == 0);
 
-  EXPECT_TRUE(DiePtr->getAttributeValue(U, Attr_DW_FORM_block1, FormValue));
+  EXPECT_TRUE(DieDG.getAttributeValue(Attr_DW_FORM_block1, FormValue));
   BlockDataOpt = FormValue.getAsBlock();
   EXPECT_TRUE(BlockDataOpt.hasValue());
   ExtractedBlockData = BlockDataOpt.getValue();
   EXPECT_EQ(ExtractedBlockData.size(), BlockSize);
   EXPECT_TRUE(memcmp(ExtractedBlockData.data(), BlockData, BlockSize) == 0);
 
-  EXPECT_TRUE(DiePtr->getAttributeValue(U, Attr_DW_FORM_block2, FormValue));
+  EXPECT_TRUE(DieDG.getAttributeValue(Attr_DW_FORM_block2, FormValue));
   BlockDataOpt = FormValue.getAsBlock();
   EXPECT_TRUE(BlockDataOpt.hasValue());
   ExtractedBlockData = BlockDataOpt.getValue();
   EXPECT_EQ(ExtractedBlockData.size(), BlockSize);
   EXPECT_TRUE(memcmp(ExtractedBlockData.data(), BlockData, BlockSize) == 0);
 
-  EXPECT_TRUE(DiePtr->getAttributeValue(U, Attr_DW_FORM_block4, FormValue));
+  EXPECT_TRUE(DieDG.getAttributeValue(Attr_DW_FORM_block4, FormValue));
   BlockDataOpt = FormValue.getAsBlock();
   EXPECT_TRUE(BlockDataOpt.hasValue());
   ExtractedBlockData = BlockDataOpt.getValue();
   EXPECT_EQ(ExtractedBlockData.size(), BlockSize);
   EXPECT_TRUE(memcmp(ExtractedBlockData.data(), BlockData, BlockSize) == 0);
 
   //----------------------------------------------------------------------
   // Test data forms
   //----------------------------------------------------------------------
   EXPECT_EQ(
-      DiePtr->getAttributeValueAsUnsignedConstant(U, Attr_DW_FORM_data1, 0),
+      DieDG.getAttributeValueAsUnsignedConstant(Attr_DW_FORM_data1, 0),
       Data1);
   EXPECT_EQ(
-      DiePtr->getAttributeValueAsUnsignedConstant(U, Attr_DW_FORM_data2, 0),
+      DieDG.getAttributeValueAsUnsignedConstant(Attr_DW_FORM_data2, 0),
       Data2);
   EXPECT_EQ(
-      DiePtr->getAttributeValueAsUnsignedConstant(U, Attr_DW_FORM_data4, 0),
+      DieDG.getAttributeValueAsUnsignedConstant(Attr_DW_FORM_data4, 0),
       Data4);
   EXPECT_EQ(
-      DiePtr->getAttributeValueAsUnsignedConstant(U, Attr_DW_FORM_data8, 0),
+      DieDG.getAttributeValueAsUnsignedConstant(Attr_DW_FORM_data8, 0),
       Data8);
 
   //----------------------------------------------------------------------
   // Test string forms
   //----------------------------------------------------------------------
   const char *ExtractedStringValue =
-      DiePtr->getAttributeValueAsString(U, Attr_DW_FORM_string, nullptr);
+      DieDG.getAttributeValueAsString(Attr_DW_FORM_string, nullptr);
   EXPECT_TRUE(ExtractedStringValue != nullptr);
   EXPECT_TRUE(strcmp(StringValue, ExtractedStringValue) == 0);
 
   const char *ExtractedStrpValue =
-      DiePtr->getAttributeValueAsString(U, Attr_DW_FORM_strp, nullptr);
+      DieDG.getAttributeValueAsString(Attr_DW_FORM_strp, nullptr);
   EXPECT_TRUE(ExtractedStrpValue != nullptr);
   EXPECT_TRUE(strcmp(StrpValue, ExtractedStrpValue) == 0);
 
   //----------------------------------------------------------------------
   // Test reference forms
   //----------------------------------------------------------------------
-  EXPECT_EQ(DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_ref_addr, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsReference(Attr_DW_FORM_ref_addr, 0),
             RefAddr);
-  EXPECT_EQ(DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_ref1, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsReference(Attr_DW_FORM_ref1, 0),
             Data1);
-  EXPECT_EQ(DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_ref2, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsReference(Attr_DW_FORM_ref2, 0),
             Data2);
-  EXPECT_EQ(DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_ref4, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsReference(Attr_DW_FORM_ref4, 0),
             Data4);
-  EXPECT_EQ(DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_ref8, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsReference(Attr_DW_FORM_ref8, 0),
             Data8);
-  EXPECT_EQ(DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_ref_sig8, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsReference(Attr_DW_FORM_ref_sig8, 0),
             Data8_2);
-  EXPECT_EQ(DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_ref_udata, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsReference(Attr_DW_FORM_ref_udata, 0),
             UData[0]);
 
   //----------------------------------------------------------------------
   // Test flag forms
   //----------------------------------------------------------------------
-  EXPECT_EQ(DiePtr->getAttributeValueAsUnsignedConstant(
-                U, Attr_DW_FORM_flag_true, 0ULL),
+  EXPECT_EQ(DieDG.getAttributeValueAsUnsignedConstant(
+                Attr_DW_FORM_flag_true, 0ULL),
             1ULL);
-  EXPECT_EQ(DiePtr->getAttributeValueAsUnsignedConstant(
-                U, Attr_DW_FORM_flag_false, 1ULL),
+  EXPECT_EQ(DieDG.getAttributeValueAsUnsignedConstant(
+                Attr_DW_FORM_flag_false, 1ULL),
             0ULL);
-  EXPECT_EQ(DiePtr->getAttributeValueAsUnsignedConstant(
-                U, Attr_DW_FORM_flag_present, 0ULL),
+  EXPECT_EQ(DieDG.getAttributeValueAsUnsignedConstant(
+                Attr_DW_FORM_flag_present, 0ULL),
             1ULL);
 
   // TODO: test Attr_DW_FORM_implicit_const extraction
 
   //----------------------------------------------------------------------
   // Test SLEB128 based forms
   //----------------------------------------------------------------------
-  EXPECT_EQ(DiePtr->getAttributeValueAsSignedConstant(U, Attr_DW_FORM_sdata, 0),
+  EXPECT_EQ(DieDG.getAttributeValueAsSignedConstant(Attr_DW_FORM_sdata, 0),
             SData);
 
   //----------------------------------------------------------------------
   // Test ULEB128 based forms
   //----------------------------------------------------------------------
   EXPECT_EQ(
-      DiePtr->getAttributeValueAsUnsignedConstant(U, Attr_DW_FORM_udata, 0),
+      DieDG.getAttributeValueAsUnsignedConstant(Attr_DW_FORM_udata, 0),
       UData[0]);
 
   //----------------------------------------------------------------------
   // Test DWARF32/DWARF64 forms
   //----------------------------------------------------------------------
   EXPECT_EQ(
-      DiePtr->getAttributeValueAsReference(U, Attr_DW_FORM_GNU_ref_alt, 0),
+      DieDG.getAttributeValueAsReference(Attr_DW_FORM_GNU_ref_alt, 0),
       Dwarf32Values[0]);
   EXPECT_EQ(
-      DiePtr->getAttributeValueAsSectionOffset(U, Attr_DW_FORM_sec_offset, 0),
+      DieDG.getAttributeValueAsSectionOffset(Attr_DW_FORM_sec_offset, 0),
       Dwarf32Values[1]);
 
   //----------------------------------------------------------------------
   // Add an address at the end to make sure we can decode this value
   //----------------------------------------------------------------------
-  EXPECT_EQ(DiePtr->getAttributeValueAsAddress(U, Attr_Last, 0), AddrValue);
+  EXPECT_EQ(DieDG.getAttributeValueAsAddress(Attr_Last, 0), AddrValue);
 }
 
 TEST(DWARFDebugInfo, TestDWARF32Version2Addr4AllForms) {
   // Test that we can decode all forms for DWARF32, version 2, with 4 byte
   // addresses.
   typedef uint32_t AddrType;
   // DW_FORM_ref_addr are the same as the address type in DWARF32 version 2.
   typedef AddrType RefAddrType;
template <uint16_t Version, class AddrType> void TestChildren() {
   DWARFContextInMemory DwarfContext(*Obj.get());
 
   // Verify the number of compile units is correct.
   uint32_t NumCUs = DwarfContext.getNumCompileUnits();
   EXPECT_EQ(NumCUs, 1u);
   DWARFCompileUnit *U = DwarfContext.getCompileUnitAtIndex(0);
 
   // Get the compile unit DIE is valid.
-  auto DiePtr = U->getUnitDIE(false);
-  EXPECT_TRUE(DiePtr != nullptr);
-  // DiePtr->dump(llvm::outs(), U, UINT32_MAX);
+  auto DieDG = U->getUnitDIE(false);
+  EXPECT_TRUE(DieDG.isValid());
+  // DieDG.dump(llvm::outs(), U, UINT32_MAX);
 
   // Verify the first child of the compile unit DIE is our subprogram.
-  auto SubprogramDiePtr = DiePtr->getFirstChild();
-  EXPECT_TRUE(SubprogramDiePtr != nullptr);
-  EXPECT_EQ(SubprogramDiePtr->getTag(), DW_TAG_subprogram);
+  auto SubprogramDieDG = DieDG.getFirstChild();
+  EXPECT_TRUE(SubprogramDieDG.isValid());
+  EXPECT_EQ(SubprogramDieDG.getTag(), DW_TAG_subprogram);
 
   // Verify the first child of the subprogram is our formal parameter.
-  auto ArgcDiePtr = SubprogramDiePtr->getFirstChild();
-  EXPECT_TRUE(ArgcDiePtr != nullptr);
-  EXPECT_EQ(ArgcDiePtr->getTag(), DW_TAG_formal_parameter);
+  auto ArgcDieDG = SubprogramDieDG.getFirstChild();
+  EXPECT_TRUE(ArgcDieDG.isValid());
+  EXPECT_EQ(ArgcDieDG.getTag(), DW_TAG_formal_parameter);
 
   // Verify our formal parameter has a NULL tag sibling.
-  auto NullDiePtr = ArgcDiePtr->getSibling();
-  EXPECT_TRUE(NullDiePtr != nullptr);
-  if (NullDiePtr) {
-    EXPECT_EQ(NullDiePtr->getTag(), DW_TAG_null);
-    EXPECT_TRUE(NullDiePtr->getSibling() == nullptr);
-    EXPECT_TRUE(NullDiePtr->getFirstChild() == nullptr);
+  auto NullDieDG = ArgcDieDG.getSibling();
+  EXPECT_TRUE(NullDieDG.isValid());
+  if (NullDieDG) {
+    EXPECT_EQ(NullDieDG.getTag(), DW_TAG_null);
+    EXPECT_TRUE(!NullDieDG.getSibling().isValid());
+    EXPECT_TRUE(!NullDieDG.getFirstChild().isValid());
   }
 
   // Verify the sibling of our subprogram is our integer base type.
-  auto IntDiePtr = SubprogramDiePtr->getSibling();
-  EXPECT_TRUE(IntDiePtr != nullptr);
-  EXPECT_EQ(IntDiePtr->getTag(), DW_TAG_base_type);
+  auto IntDieDG = SubprogramDieDG.getSibling();
+  EXPECT_TRUE(IntDieDG.isValid());
+  EXPECT_EQ(IntDieDG.getTag(), DW_TAG_base_type);
 
   // Verify the sibling of our subprogram is our integer base is a NULL tag.
-  NullDiePtr = IntDiePtr->getSibling();
-  EXPECT_TRUE(NullDiePtr != nullptr);
-  if (NullDiePtr) {
-    EXPECT_EQ(NullDiePtr->getTag(), DW_TAG_null);
-    EXPECT_TRUE(NullDiePtr->getSibling() == nullptr);
-    EXPECT_TRUE(NullDiePtr->getFirstChild() == nullptr);
+  NullDieDG = IntDieDG.getSibling();
+  EXPECT_TRUE(NullDieDG.isValid());
+  if (NullDieDG) {
+    EXPECT_EQ(NullDieDG.getTag(), DW_TAG_null);
+    EXPECT_TRUE(!NullDieDG.getSibling().isValid());
+    EXPECT_TRUE(!NullDieDG.getFirstChild().isValid());
   }
 }
 
 TEST(DWARFDebugInfo, TestDWARF32Version2Addr4Children) {
   // Test that we can decode all forms for DWARF32, version 2, with 4 byte
   // addresses.
   typedef uint32_t AddrType;
   TestChildren<2, AddrType>();
template <uint16_t Version, class AddrType> void TestReferences() {
 
   // Verify the number of compile units is correct.
   uint32_t NumCUs = DwarfContext.getNumCompileUnits();
   EXPECT_EQ(NumCUs, 2u);
   DWARFCompileUnit *U1 = DwarfContext.getCompileUnitAtIndex(0);
   DWARFCompileUnit *U2 = DwarfContext.getCompileUnitAtIndex(1);
 
   // Get the compile unit DIE is valid.
-  auto Unit1DiePtr = U1->getUnitDIE(false);
-  EXPECT_TRUE(Unit1DiePtr != nullptr);
-  // Unit1DiePtr->dump(llvm::outs(), U1, UINT32_MAX);
-
-  auto Unit2DiePtr = U2->getUnitDIE(false);
-  EXPECT_TRUE(Unit2DiePtr != nullptr);
-  // Unit2DiePtr->dump(llvm::outs(), U2, UINT32_MAX);
+  auto Unit1DieDG = U1->getUnitDIE(false);
+  EXPECT_TRUE(Unit1DieDG.isValid());
+  // Unit1DieDG.dump(llvm::outs(), UINT32_MAX);
+
+  auto Unit2DieDG = U2->getUnitDIE(false);
+  EXPECT_TRUE(Unit2DieDG.isValid());
+  // Unit2DieDG.dump(llvm::outs(), UINT32_MAX);
 
   // Verify the first child of the compile unit 1 DIE is our int base type.
-  auto CU1TypeDiePtr = Unit1DiePtr->getFirstChild();
-  EXPECT_TRUE(CU1TypeDiePtr != nullptr);
-  EXPECT_EQ(CU1TypeDiePtr->getTag(), DW_TAG_base_type);
+  auto CU1TypeDieDG = Unit1DieDG.getFirstChild();
+  EXPECT_TRUE(CU1TypeDieDG.isValid());
+  EXPECT_EQ(CU1TypeDieDG.getTag(), DW_TAG_base_type);
   EXPECT_EQ(
-      CU1TypeDiePtr->getAttributeValueAsUnsignedConstant(U1, DW_AT_encoding, 0),
+      CU1TypeDieDG.getAttributeValueAsUnsignedConstant(DW_AT_encoding, 0),
       DW_ATE_signed);
 
   // Verify the first child of the compile unit 2 DIE is our float base type.
-  auto CU2TypeDiePtr = Unit2DiePtr->getFirstChild();
-  EXPECT_TRUE(CU2TypeDiePtr != nullptr);
-  EXPECT_EQ(CU2TypeDiePtr->getTag(), DW_TAG_base_type);
+  auto CU2TypeDieDG = Unit2DieDG.getFirstChild();
+  EXPECT_TRUE(CU2TypeDieDG.isValid());
+  EXPECT_EQ(CU2TypeDieDG.getTag(), DW_TAG_base_type);
   EXPECT_EQ(
-      CU2TypeDiePtr->getAttributeValueAsUnsignedConstant(U2, DW_AT_encoding, 0),
+      CU2TypeDieDG.getAttributeValueAsUnsignedConstant(DW_AT_encoding, 0),
       DW_ATE_float);
 
   // Verify the sibling of the base type DIE is our Ref1 DIE and that its
   // DW_AT_type points to our base type DIE.
-  auto CU1Ref1DiePtr = CU1TypeDiePtr->getSibling();
-  EXPECT_TRUE(CU1Ref1DiePtr != nullptr);
-  EXPECT_EQ(CU1Ref1DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU1Ref1DiePtr->getAttributeValueAsReference(U1, DW_AT_type, -1ULL),
-            CU1TypeDiePtr->getOffset());
+  auto CU1Ref1DieDG = CU1TypeDieDG.getSibling();
+  EXPECT_TRUE(CU1Ref1DieDG.isValid());
+  EXPECT_EQ(CU1Ref1DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU1Ref1DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU1TypeDieDG.getOffset());
   // Verify the sibling is our Ref2 DIE and that its DW_AT_type points to our
   // base type DIE in CU1.
-  auto CU1Ref2DiePtr = CU1Ref1DiePtr->getSibling();
-  EXPECT_TRUE(CU1Ref2DiePtr != nullptr);
-  EXPECT_EQ(CU1Ref2DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU1Ref2DiePtr->getAttributeValueAsReference(U1, DW_AT_type, -1ULL),
-            CU1TypeDiePtr->getOffset());
+  auto CU1Ref2DieDG = CU1Ref1DieDG.getSibling();
+  EXPECT_TRUE(CU1Ref2DieDG.isValid());
+  EXPECT_EQ(CU1Ref2DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU1Ref2DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU1TypeDieDG.getOffset());
 
   // Verify the sibling is our Ref4 DIE and that its DW_AT_type points to our
   // base type DIE in CU1.
-  auto CU1Ref4DiePtr = CU1Ref2DiePtr->getSibling();
-  EXPECT_TRUE(CU1Ref4DiePtr != nullptr);
-  EXPECT_EQ(CU1Ref4DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU1Ref4DiePtr->getAttributeValueAsReference(U1, DW_AT_type, -1ULL),
-            CU1TypeDiePtr->getOffset());
+  auto CU1Ref4DieDG = CU1Ref2DieDG.getSibling();
+  EXPECT_TRUE(CU1Ref4DieDG.isValid());
+  EXPECT_EQ(CU1Ref4DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU1Ref4DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU1TypeDieDG.getOffset());
 
   // Verify the sibling is our Ref8 DIE and that its DW_AT_type points to our
   // base type DIE in CU1.
-  auto CU1Ref8DiePtr = CU1Ref4DiePtr->getSibling();
-  EXPECT_TRUE(CU1Ref8DiePtr != nullptr);
-  EXPECT_EQ(CU1Ref8DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU1Ref8DiePtr->getAttributeValueAsReference(U1, DW_AT_type, -1ULL),
-            CU1TypeDiePtr->getOffset());
+  auto CU1Ref8DieDG = CU1Ref4DieDG.getSibling();
+  EXPECT_TRUE(CU1Ref8DieDG.isValid());
+  EXPECT_EQ(CU1Ref8DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU1Ref8DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU1TypeDieDG.getOffset());
 
   // Verify the sibling is our RefAddr DIE and that its DW_AT_type points to our
   // base type DIE in CU1.
-  auto CU1RefAddrDiePtr = CU1Ref8DiePtr->getSibling();
-  EXPECT_TRUE(CU1RefAddrDiePtr != nullptr);
-  EXPECT_EQ(CU1RefAddrDiePtr->getTag(), DW_TAG_variable);
+  auto CU1RefAddrDieDG = CU1Ref8DieDG.getSibling();
+  EXPECT_TRUE(CU1RefAddrDieDG.isValid());
+  EXPECT_EQ(CU1RefAddrDieDG.getTag(), DW_TAG_variable);
   EXPECT_EQ(
-      CU1RefAddrDiePtr->getAttributeValueAsReference(U1, DW_AT_type, -1ULL),
-      CU1TypeDiePtr->getOffset());
+      CU1RefAddrDieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+      CU1TypeDieDG.getOffset());
 
   // Verify the sibling of the Ref4 DIE is our RefAddr DIE and that its
   // DW_AT_type points to our base type DIE.
-  auto CU1ToCU2RefAddrDiePtr = CU1RefAddrDiePtr->getSibling();
-  EXPECT_TRUE(CU1ToCU2RefAddrDiePtr != nullptr);
-  EXPECT_EQ(CU1ToCU2RefAddrDiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU1ToCU2RefAddrDiePtr->getAttributeValueAsReference(U1, DW_AT_type,
+  auto CU1ToCU2RefAddrDieDG = CU1RefAddrDieDG.getSibling();
+  EXPECT_TRUE(CU1ToCU2RefAddrDieDG.isValid());
+  EXPECT_EQ(CU1ToCU2RefAddrDieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU1ToCU2RefAddrDieDG.getAttributeValueAsReference(DW_AT_type,
                                                                 -1ULL),
-            CU2TypeDiePtr->getOffset());
+            CU2TypeDieDG.getOffset());
 
   // Verify the sibling of the base type DIE is our Ref1 DIE and that its
   // DW_AT_type points to our base type DIE.
-  auto CU2Ref1DiePtr = CU2TypeDiePtr->getSibling();
-  EXPECT_TRUE(CU2Ref1DiePtr != nullptr);
-  EXPECT_EQ(CU2Ref1DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU2Ref1DiePtr->getAttributeValueAsReference(U2, DW_AT_type, -1ULL),
-            CU2TypeDiePtr->getOffset());
+  auto CU2Ref1DieDG = CU2TypeDieDG.getSibling();
+  EXPECT_TRUE(CU2Ref1DieDG.isValid());
+  EXPECT_EQ(CU2Ref1DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU2Ref1DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU2TypeDieDG.getOffset());
   // Verify the sibling is our Ref2 DIE and that its DW_AT_type points to our
   // base type DIE in CU2.
-  auto CU2Ref2DiePtr = CU2Ref1DiePtr->getSibling();
-  EXPECT_TRUE(CU2Ref2DiePtr != nullptr);
-  EXPECT_EQ(CU2Ref2DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU2Ref2DiePtr->getAttributeValueAsReference(U2, DW_AT_type, -1ULL),
-            CU2TypeDiePtr->getOffset());
+  auto CU2Ref2DieDG = CU2Ref1DieDG.getSibling();
+  EXPECT_TRUE(CU2Ref2DieDG.isValid());
+  EXPECT_EQ(CU2Ref2DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU2Ref2DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU2TypeDieDG.getOffset());
 
   // Verify the sibling is our Ref4 DIE and that its DW_AT_type points to our
   // base type DIE in CU2.
-  auto CU2Ref4DiePtr = CU2Ref2DiePtr->getSibling();
-  EXPECT_TRUE(CU2Ref4DiePtr != nullptr);
-  EXPECT_EQ(CU2Ref4DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU2Ref4DiePtr->getAttributeValueAsReference(U2, DW_AT_type, -1ULL),
-            CU2TypeDiePtr->getOffset());
+  auto CU2Ref4DieDG = CU2Ref2DieDG.getSibling();
+  EXPECT_TRUE(CU2Ref4DieDG.isValid());
+  EXPECT_EQ(CU2Ref4DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU2Ref4DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU2TypeDieDG.getOffset());
 
   // Verify the sibling is our Ref8 DIE and that its DW_AT_type points to our
   // base type DIE in CU2.
-  auto CU2Ref8DiePtr = CU2Ref4DiePtr->getSibling();
-  EXPECT_TRUE(CU2Ref8DiePtr != nullptr);
-  EXPECT_EQ(CU2Ref8DiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU2Ref8DiePtr->getAttributeValueAsReference(U2, DW_AT_type, -1ULL),
-            CU2TypeDiePtr->getOffset());
+  auto CU2Ref8DieDG = CU2Ref4DieDG.getSibling();
+  EXPECT_TRUE(CU2Ref8DieDG.isValid());
+  EXPECT_EQ(CU2Ref8DieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU2Ref8DieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+            CU2TypeDieDG.getOffset());
 
   // Verify the sibling is our RefAddr DIE and that its DW_AT_type points to our
   // base type DIE in CU2.
-  auto CU2RefAddrDiePtr = CU2Ref8DiePtr->getSibling();
-  EXPECT_TRUE(CU2RefAddrDiePtr != nullptr);
-  EXPECT_EQ(CU2RefAddrDiePtr->getTag(), DW_TAG_variable);
+  auto CU2RefAddrDieDG = CU2Ref8DieDG.getSibling();
+  EXPECT_TRUE(CU2RefAddrDieDG.isValid());
+  EXPECT_EQ(CU2RefAddrDieDG.getTag(), DW_TAG_variable);
   EXPECT_EQ(
-      CU2RefAddrDiePtr->getAttributeValueAsReference(U2, DW_AT_type, -1ULL),
-      CU2TypeDiePtr->getOffset());
+      CU2RefAddrDieDG.getAttributeValueAsReference(DW_AT_type, -1ULL),
+      CU2TypeDieDG.getOffset());
 
   // Verify the sibling of the Ref4 DIE is our RefAddr DIE and that its
   // DW_AT_type points to our base type DIE.
-  auto CU2ToCU1RefAddrDiePtr = CU2RefAddrDiePtr->getSibling();
-  EXPECT_TRUE(CU2ToCU1RefAddrDiePtr != nullptr);
-  EXPECT_EQ(CU2ToCU1RefAddrDiePtr->getTag(), DW_TAG_variable);
-  EXPECT_EQ(CU2ToCU1RefAddrDiePtr->getAttributeValueAsReference(U2, DW_AT_type,
+  auto CU2ToCU1RefAddrDieDG = CU2RefAddrDieDG.getSibling();
+  EXPECT_TRUE(CU2ToCU1RefAddrDieDG.isValid());
+  EXPECT_EQ(CU2ToCU1RefAddrDieDG.getTag(), DW_TAG_variable);
+  EXPECT_EQ(CU2ToCU1RefAddrDieDG.getAttributeValueAsReference(DW_AT_type,
                                                                 -1ULL),
-            CU1TypeDiePtr->getOffset());
+            CU1TypeDieDG.getOffset());
 }
 
 TEST(DWARFDebugInfo, TestDWARF32Version2Addr4References) {
   // Test that we can decode all forms for DWARF32, version 2, with 4 byte
   // addresses.
   typedef uint32_t AddrType;
   TestReferences<2, AddrType>();
 }

unittests/DebugInfo/DWARF/DwarfGenerator.cpp

 //===--- unittests/DebugInfo/DWARF/DwarfGenerator.cpp -----------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "../lib/CodeGen/AsmPrinter/DwarfStringPool.h"
 #include "DwarfGenerator.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/DIE.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
-#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/IR/LegacyPassManagers.h"
 #include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDwarf.h"