[DebugInfo] Delete TypedDINodeRef

[MaskRay]

Summary

TypedDINodeRef<T> is a redundant wrapper of Metadata * that is actually a T *.

Accordingly, change DI{Node,Scope,Type}Ref uses to {const,} DI{Node,Scope,Type} *
This allows us to delete many resolve() calls that clutter the code.

[labath]

I don't feel qualified to review this patch.

[MaskRay]

Ping @dexonsmith @aprantl ☺

[dexonsmith]

+rnk

include/llvm/IR/DebugInfoMetadata.h

65–69

I can confirm the original motivation (MDString-based ODR-uniquing). @rnk, is it still thought to be useful for CodeView?

[rnk]

lgtm, thanks!

include/llvm/IR/DebugInfoMetadata.h

65–69

No, we don't need it, we should do this cleanup.

include/llvm/CodeGen/DebugHandlerBase.h

public:
   /// Return Label immediately following the instruction.
   MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
 
   /// Return the function-local offset of an instruction. A label for the
   /// instruction \p MI should exist (\ref getLabelAfterInsn).
   const MCExpr *getFunctionLocalOffsetAfterInsn(const MachineInstr *MI);
 
   /// If this type is derived from a base type then return base type size.
-  static uint64_t getBaseTypeSize(const DITypeRef TyRef);
+  static uint64_t getBaseTypeSize(const DIType *Ty);
 };
 
 }
 
 #endif

include/llvm/IR/DebugInfoMetadata.h

static CLASS *getIfExists(LLVMContext &Context,                              \
                             DEFINE_MDNODE_GET_UNPACK(FORMAL)) {                \
     return getImpl(Context, DEFINE_MDNODE_GET_UNPACK(ARGS), Uniqued,           \
                    /* ShouldCreate */ false);                                  \
   }                                                                            \
   DEFINE_MDNODE_GET_DISTINCT_TEMPORARY(CLASS, FORMAL, ARGS)
 
 namespace llvm {
 
-/// Holds a subclass of DINode.
-///
-/// FIXME: This class doesn't currently make much sense.  Previously it was a
-/// union beteen MDString (for ODR-uniqued types) and things like DIType.  To
-/// support CodeView work, it wasn't deleted outright when MDString-based type
-/// references were deleted; we'll soon need a similar concept for CodeView
-/// DITypeIndex.
-template <class T> class TypedDINodeRef {
-  const Metadata *MD = nullptr;
-
-public:
-  TypedDINodeRef() = default;
-  TypedDINodeRef(std::nullptr_t) {}
-  TypedDINodeRef(const T *MD) : MD(MD) {}
-
-  explicit TypedDINodeRef(const Metadata *MD) : MD(MD) {
-    assert((!MD || isa<T>(MD)) && "Expected valid type ref");
-  }
-
-  template <class U>
-  TypedDINodeRef(
-      const TypedDINodeRef<U> &X,
-      typename std::enable_if<std::is_convertible<U *, T *>::value>::type * =
-          nullptr)
-      : MD(X) {}
-
-  operator Metadata *() const { return const_cast<Metadata *>(MD); }
-
-  T *resolve() const { return const_cast<T *>(cast_or_null<T>(MD)); }
-
-  bool operator==(const TypedDINodeRef<T> &X) const { return MD == X.MD; }
-  bool operator!=(const TypedDINodeRef<T> &X) const { return MD != X.MD; }
-};
-
-using DINodeRef = TypedDINodeRef<DINode>;
-using DIScopeRef = TypedDINodeRef<DIScope>;
-using DITypeRef = TypedDINodeRef<DIType>;
-
 class DITypeRefArray {
   const MDTuple *N = nullptr;
 
 public:
   DITypeRefArray() = default;
   DITypeRefArray(const MDTuple *N) : N(N) {}
 
   explicit operator bool() const { return get(); }
   explicit operator MDTuple *() const { return get(); }
 
   MDTuple *get() const { return const_cast<MDTuple *>(N); }
   MDTuple *operator->() const { return get(); }
   MDTuple &operator*() const { return *get(); }
 
   // FIXME: Fix callers and remove condition on N.
   unsigned size() const { return N ? N->getNumOperands() : 0u; }
-  DITypeRef operator[](unsigned I) const { return DITypeRef(N->getOperand(I)); }
+  DIType *operator[](unsigned I) const {
+    return cast_or_null<DIType>(N->getOperand(I));
+  }
 
-  class iterator : std::iterator<std::input_iterator_tag, DITypeRef,
-                                 std::ptrdiff_t, void, DITypeRef> {
+  class iterator : std::iterator<std::input_iterator_tag, DIType *,
+                                 std::ptrdiff_t, void, DIType *> {
     MDNode::op_iterator I = nullptr;
 
   public:
     iterator() = default;
     explicit iterator(MDNode::op_iterator I) : I(I) {}
 
-    DITypeRef operator*() const { return DITypeRef(*I); }
+    DIType *operator*() const { return cast_or_null<DIType>(*I); }
 
     iterator &operator++() {
       ++I;
       return *this;
     }
 
     iterator operator++(int) {
       iterator Temp(*this);
static bool classof(const Metadata *MD) {
     case DIObjCPropertyKind:
     case DIImportedEntityKind:
     case DIModuleKind:
       return true;
     }
   }
 };
 
-template <class T> struct simplify_type<const TypedDINodeRef<T>> {
-  using SimpleType = Metadata *;
-
-  static SimpleType getSimplifiedValue(const TypedDINodeRef<T> &MD) {
-    return MD;
-  }
-};
-
-template <class T>
-struct simplify_type<TypedDINodeRef<T>>
-    : simplify_type<const TypedDINodeRef<T>> {};
-
 /// Generic tagged DWARF-like metadata node.
 ///
 /// An un-specialized DWARF-like metadata node.  The first operand is a
 /// (possibly empty) null-separated \a MDString header that contains arbitrary
 /// fields.  The remaining operands are \a dwarf_operands(), and are pointers
 /// to other metadata.
 class GenericDINode : public DINode {
   friend class LLVMContextImpl;

 public:
   DIFile *getFile() const { return cast_or_null<DIFile>(getRawFile()); }
 
   inline StringRef getFilename() const;
   inline StringRef getDirectory() const;
   inline Optional<StringRef> getSource() const;
 
   StringRef getName() const;
-  DIScopeRef getScope() const;
+  DIScope *getScope() const;
 
   /// Return the raw underlying file.
   ///
   /// A \a DIFile is a \a DIScope, but it doesn't point at a separate file (it
   /// \em is the file).  If \c this is an \a DIFile, we need to return \c this.
   /// Otherwise, return the first operand, which is where all other subclasses
   /// store their file pointer.
   Metadata *getRawFile() const {
public:
 
   unsigned getLine() const { return Line; }
   uint64_t getSizeInBits() const { return SizeInBits; }
   uint32_t getAlignInBits() const { return AlignInBits; }
   uint32_t getAlignInBytes() const { return getAlignInBits() / CHAR_BIT; }
   uint64_t getOffsetInBits() const { return OffsetInBits; }
   DIFlags getFlags() const { return Flags; }
 
-  DIScopeRef getScope() const { return DIScopeRef(getRawScope()); }
+  DIScope *getScope() const { return cast_or_null<DIScope>(getRawScope()); }
   StringRef getName() const { return getStringOperand(2); }
 
 
   Metadata *getRawScope() const { return getOperand(1); }
   MDString *getRawName() const { return getOperandAs<MDString>(2); }
 
   /// Returns a new temporary DIType with updated Flags
   TempDIType cloneWithFlags(DIFlags NewFlags) const {
DIDerivedType(LLVMContext &C, StorageType Storage, unsigned Tag,
                 unsigned Line, uint64_t SizeInBits, uint32_t AlignInBits,
                 uint64_t OffsetInBits, Optional<unsigned> DWARFAddressSpace,
                 DIFlags Flags, ArrayRef<Metadata *> Ops)
       : DIType(C, DIDerivedTypeKind, Storage, Tag, Line, SizeInBits,
                AlignInBits, OffsetInBits, Flags, Ops),
         DWARFAddressSpace(DWARFAddressSpace) {}
   ~DIDerivedType() = default;
 
-  static DIDerivedType *getImpl(LLVMContext &Context, unsigned Tag,
-                                StringRef Name, DIFile *File, unsigned Line,
-                                DIScopeRef Scope, DITypeRef BaseType,
-                                uint64_t SizeInBits, uint32_t AlignInBits,
-                                uint64_t OffsetInBits,
-                                Optional<unsigned> DWARFAddressSpace,
-                                DIFlags Flags, Metadata *ExtraData,
-                                StorageType Storage, bool ShouldCreate = true) {
+  static DIDerivedType *
+  getImpl(LLVMContext &Context, unsigned Tag, StringRef Name, DIFile *File,
+          unsigned Line, DIScope *Scope, DIType *BaseType, uint64_t SizeInBits,
+          uint32_t AlignInBits, uint64_t OffsetInBits,
+          Optional<unsigned> DWARFAddressSpace, DIFlags Flags,
+          Metadata *ExtraData, StorageType Storage, bool ShouldCreate = true) {
     return getImpl(Context, Tag, getCanonicalMDString(Context, Name), File,
                    Line, Scope, BaseType, SizeInBits, AlignInBits, OffsetInBits,
                    DWARFAddressSpace, Flags, ExtraData, Storage, ShouldCreate);
   }
   static DIDerivedType *getImpl(LLVMContext &Context, unsigned Tag,
                                 MDString *Name, Metadata *File, unsigned Line,
                                 Metadata *Scope, Metadata *BaseType,
                                 uint64_t SizeInBits, uint32_t AlignInBits,
DEFINE_MDNODE_GET(DIDerivedType,
                      uint64_t OffsetInBits,
                      Optional<unsigned> DWARFAddressSpace, DIFlags Flags,
                      Metadata *ExtraData = nullptr),
                     (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
                      AlignInBits, OffsetInBits, DWARFAddressSpace, Flags,
                      ExtraData))
   DEFINE_MDNODE_GET(DIDerivedType,
                     (unsigned Tag, StringRef Name, DIFile *File, unsigned Line,
-                     DIScopeRef Scope, DITypeRef BaseType, uint64_t SizeInBits,
+                     DIScope *Scope, DIType *BaseType, uint64_t SizeInBits,
                      uint32_t AlignInBits, uint64_t OffsetInBits,
                      Optional<unsigned> DWARFAddressSpace, DIFlags Flags,
                      Metadata *ExtraData = nullptr),
                     (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
                      AlignInBits, OffsetInBits, DWARFAddressSpace, Flags,
                      ExtraData))
 
   TempDIDerivedType clone() const { return cloneImpl(); }
 
   /// Get the base type this is derived from.
-  DITypeRef getBaseType() const { return DITypeRef(getRawBaseType()); }
+  DIType *getBaseType() const { return cast_or_null<DIType>(getRawBaseType()); }
   Metadata *getRawBaseType() const { return getOperand(3); }
 
   /// \returns The DWARF address space of the memory pointed to or referenced by
   /// a pointer or reference type respectively.
   Optional<unsigned> getDWARFAddressSpace() const { return DWARFAddressSpace; }
 
   /// Get extra data associated with this derived type.
   ///
   /// Class type for pointer-to-members, objective-c property node for ivars,
   /// global constant wrapper for static members, or virtual base pointer offset
   /// for inheritance.
   ///
   /// TODO: Separate out types that need this extra operand: pointer-to-member
   /// types and member fields (static members and ivars).
   Metadata *getExtraData() const { return getRawExtraData(); }
   Metadata *getRawExtraData() const { return getOperand(4); }
 
   /// Get casted version of extra data.
   /// @{
-  DITypeRef getClassType() const {
+  DIType *getClassType() const {
     assert(getTag() == dwarf::DW_TAG_ptr_to_member_type);
-    return DITypeRef(getExtraData());
+    return cast_or_null<DIType>(getExtraData());
   }
 
   DIObjCProperty *getObjCProperty() const {
     return dyn_cast_or_null<DIObjCProperty>(getExtraData());
   }
 
   uint32_t getVBPtrOffset() const {
     assert(getTag() == dwarf::DW_TAG_inheritance);
void mutate(unsigned Tag, unsigned Line, unsigned RuntimeLang,
     assert(isDistinct() && "Only distinct nodes can mutate");
     assert(getRawIdentifier() && "Only ODR-uniqued nodes should mutate");
     this->RuntimeLang = RuntimeLang;
     DIType::mutate(Tag, Line, SizeInBits, AlignInBits, OffsetInBits, Flags);
   }
 
   static DICompositeType *
   getImpl(LLVMContext &Context, unsigned Tag, StringRef Name, Metadata *File,
-          unsigned Line, DIScopeRef Scope, DITypeRef BaseType,
-          uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
-          DIFlags Flags, DINodeArray Elements, unsigned RuntimeLang,
-          DITypeRef VTableHolder, DITemplateParameterArray TemplateParams,
-          StringRef Identifier, DIDerivedType *Discriminator,
-          StorageType Storage, bool ShouldCreate = true) {
+          unsigned Line, DIScope *Scope, DIType *BaseType, uint64_t SizeInBits,
+          uint32_t AlignInBits, uint64_t OffsetInBits, DIFlags Flags,
+          DINodeArray Elements, unsigned RuntimeLang, DIType *VTableHolder,
+          DITemplateParameterArray TemplateParams, StringRef Identifier,
+          DIDerivedType *Discriminator, StorageType Storage,
+          bool ShouldCreate = true) {
     return getImpl(
         Context, Tag, getCanonicalMDString(Context, Name), File, Line, Scope,
         BaseType, SizeInBits, AlignInBits, OffsetInBits, Flags, Elements.get(),
         RuntimeLang, VTableHolder, TemplateParams.get(),
         getCanonicalMDString(Context, Identifier), Discriminator, Storage, ShouldCreate);
   }
   static DICompositeType *
   getImpl(LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
return getTemporary(getContext(), getTag(), getName(), getFile(), getLine(),
                         getAlignInBits(), getOffsetInBits(), getFlags(),
                         getElements(), getRuntimeLang(), getVTableHolder(),
                         getTemplateParams(), getIdentifier(), getDiscriminator());
   }
 
 public:
   DEFINE_MDNODE_GET(DICompositeType,
                     (unsigned Tag, StringRef Name, DIFile *File, unsigned Line,
-                     DIScopeRef Scope, DITypeRef BaseType, uint64_t SizeInBits,
-                     uint32_t AlignInBits, uint64_t OffsetInBits,
-                     DIFlags Flags, DINodeArray Elements, unsigned RuntimeLang,
-                     DITypeRef VTableHolder,
+                     DIScope *Scope, DIType *BaseType, uint64_t SizeInBits,
+                     uint32_t AlignInBits, uint64_t OffsetInBits, DIFlags Flags,
+                     DINodeArray Elements, unsigned RuntimeLang,
+                     DIType *VTableHolder,
                      DITemplateParameterArray TemplateParams = nullptr,
-                     StringRef Identifier = "", DIDerivedType *Discriminator = nullptr),
+                     StringRef Identifier = "",
+                     DIDerivedType *Discriminator = nullptr),
                     (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
                      AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
                      VTableHolder, TemplateParams, Identifier, Discriminator))
   DEFINE_MDNODE_GET(DICompositeType,
                     (unsigned Tag, MDString *Name, Metadata *File,
                      unsigned Line, Metadata *Scope, Metadata *BaseType,
                      uint64_t SizeInBits, uint32_t AlignInBits,
                      uint64_t OffsetInBits, DIFlags Flags, Metadata *Elements,
public:
   static DICompositeType *
   buildODRType(LLVMContext &Context, MDString &Identifier, unsigned Tag,
                MDString *Name, Metadata *File, unsigned Line, Metadata *Scope,
                Metadata *BaseType, uint64_t SizeInBits, uint32_t AlignInBits,
                uint64_t OffsetInBits, DIFlags Flags, Metadata *Elements,
                unsigned RuntimeLang, Metadata *VTableHolder,
                Metadata *TemplateParams, Metadata *Discriminator);
 
-  DITypeRef getBaseType() const { return DITypeRef(getRawBaseType()); }
+  DIType *getBaseType() const { return cast_or_null<DIType>(getRawBaseType()); }
   DINodeArray getElements() const {
     return cast_or_null<MDTuple>(getRawElements());
   }
-  DITypeRef getVTableHolder() const { return DITypeRef(getRawVTableHolder()); }
+  DIType *getVTableHolder() const {
+    return cast_or_null<DIType>(getRawVTableHolder());
+  }
   DITemplateParameterArray getTemplateParams() const {
     return cast_or_null<MDTuple>(getRawTemplateParams());
   }
   StringRef getIdentifier() const { return getStringOperand(7); }
   unsigned getRuntimeLang() const { return RuntimeLang; }
 
   Metadata *getRawBaseType() const { return getOperand(3); }
   Metadata *getRawElements() const { return getOperand(4); }

 #ifndef NDEBUG
     for (DINode *Op : getElements())
       assert(is_contained(Elements->operands(), Op) &&
              "Lost a member during member list replacement");
 #endif
     replaceOperandWith(4, Elements.get());
   }
 
-  void replaceVTableHolder(DITypeRef VTableHolder) {
+  void replaceVTableHolder(DIType *VTableHolder) {
     replaceOperandWith(5, VTableHolder);
   }
 
   void replaceTemplateParams(DITemplateParameterArray TemplateParams) {
     replaceOperandWith(6, TemplateParams.get());
   }
   /// @}
 
DISubprogram(LLVMContext &C, StorageType Storage, unsigned Line,
                      Ops),
         Line(Line), ScopeLine(ScopeLine), VirtualIndex(VirtualIndex),
         ThisAdjustment(ThisAdjustment), Flags(Flags), SPFlags(SPFlags) {
     static_assert(dwarf::DW_VIRTUALITY_max < 4, "Virtuality out of range");
   }
   ~DISubprogram() = default;
 
   static DISubprogram *
-  getImpl(LLVMContext &Context, DIScopeRef Scope, StringRef Name,
+  getImpl(LLVMContext &Context, DIScope *Scope, StringRef Name,
           StringRef LinkageName, DIFile *File, unsigned Line,
-          DISubroutineType *Type, unsigned ScopeLine, DITypeRef ContainingType,
+          DISubroutineType *Type, unsigned ScopeLine, DIType *ContainingType,
           unsigned VirtualIndex, int ThisAdjustment, DIFlags Flags,
           DISPFlags SPFlags, DICompileUnit *Unit,
           DITemplateParameterArray TemplateParams, DISubprogram *Declaration,
           DINodeArray RetainedNodes, DITypeArray ThrownTypes,
           StorageType Storage, bool ShouldCreate = true) {
     return getImpl(Context, Scope, getCanonicalMDString(Context, Name),
                    getCanonicalMDString(Context, LinkageName), File, Line, Type,
                    ScopeLine, ContainingType, VirtualIndex, ThisAdjustment,
return getTemporary(getContext(), getScope(), getName(), getLinkageName(),
                         getThisAdjustment(), getFlags(), getSPFlags(),
                         getUnit(), getTemplateParams(), getDeclaration(),
                         getRetainedNodes(), getThrownTypes());
   }
 
 public:
   DEFINE_MDNODE_GET(
       DISubprogram,
-      (DIScopeRef Scope, StringRef Name, StringRef LinkageName, DIFile *File,
+      (DIScope * Scope, StringRef Name, StringRef LinkageName, DIFile *File,
        unsigned Line, DISubroutineType *Type, unsigned ScopeLine,
-       DITypeRef ContainingType, unsigned VirtualIndex, int ThisAdjustment,
+       DIType *ContainingType, unsigned VirtualIndex, int ThisAdjustment,
        DIFlags Flags, DISPFlags SPFlags, DICompileUnit *Unit,
        DITemplateParameterArray TemplateParams = nullptr,
        DISubprogram *Declaration = nullptr, DINodeArray RetainedNodes = nullptr,
        DITypeArray ThrownTypes = nullptr),
       (Scope, Name, LinkageName, File, Line, Type, ScopeLine, ContainingType,
        VirtualIndex, ThisAdjustment, Flags, SPFlags, Unit, TemplateParams,
        Declaration, RetainedNodes, ThrownTypes))
 
public:
   /// Return true if this subprogram is C++11 noreturn or C11 _Noreturn
   bool isNoReturn() const { return getFlags() & FlagNoReturn; }
 
   // Check if this routine is a compiler-generated thunk.
   //
   // Returns true if this subprogram is a thunk generated by the compiler.
   bool isThunk() const { return getFlags() & FlagThunk; }
 
-  DIScopeRef getScope() const { return DIScopeRef(getRawScope()); }
+  DIScope *getScope() const { return cast_or_null<DIScope>(getRawScope()); }
 
   StringRef getName() const { return getStringOperand(2); }
   StringRef getLinkageName() const { return getStringOperand(3); }
 
   DISubroutineType *getType() const {
     return cast_or_null<DISubroutineType>(getRawType());
   }
-  DITypeRef getContainingType() const {
-    return DITypeRef(getRawContainingType());
+  DIType *getContainingType() const {
+    return cast_or_null<DIType>(getRawContainingType());
   }
 
   DICompileUnit *getUnit() const {
     return cast_or_null<DICompileUnit>(getRawUnit());
   }
   void replaceUnit(DICompileUnit *CU) { replaceOperandWith(5, CU); }
   DITemplateParameterArray getTemplateParams() const {
     return cast_or_null<MDTuple>(getRawTemplateParams());

 protected:
   DITemplateParameter(LLVMContext &Context, unsigned ID, StorageType Storage,
                       unsigned Tag, ArrayRef<Metadata *> Ops)
       : DINode(Context, ID, Storage, Tag, Ops) {}
   ~DITemplateParameter() = default;
 
 public:
   StringRef getName() const { return getStringOperand(0); }
-  DITypeRef getType() const { return DITypeRef(getRawType()); }
+  DIType *getType() const { return cast_or_null<DIType>(getRawType()); }
 
   MDString *getRawName() const { return getOperandAs<MDString>(0); }
   Metadata *getRawType() const { return getOperand(1); }
 
   static bool classof(const Metadata *MD) {
     return MD->getMetadataID() == DITemplateTypeParameterKind ||
            MD->getMetadataID() == DITemplateValueParameterKind;
   }
 };
 
 class DITemplateTypeParameter : public DITemplateParameter {
   friend class LLVMContextImpl;
   friend class MDNode;
 
   DITemplateTypeParameter(LLVMContext &Context, StorageType Storage,
                           ArrayRef<Metadata *> Ops)
       : DITemplateParameter(Context, DITemplateTypeParameterKind, Storage,
                             dwarf::DW_TAG_template_type_parameter, Ops) {}
   ~DITemplateTypeParameter() = default;
 
   static DITemplateTypeParameter *getImpl(LLVMContext &Context, StringRef Name,
-                                          DITypeRef Type, StorageType Storage,
+                                          DIType *Type, StorageType Storage,
                                           bool ShouldCreate = true) {
     return getImpl(Context, getCanonicalMDString(Context, Name), Type, Storage,
                    ShouldCreate);
   }
   static DITemplateTypeParameter *getImpl(LLVMContext &Context, MDString *Name,
                                           Metadata *Type, StorageType Storage,
                                           bool ShouldCreate = true);
 
   TempDITemplateTypeParameter cloneImpl() const {
     return getTemporary(getContext(), getName(), getType());
   }
 
 public:
-  DEFINE_MDNODE_GET(DITemplateTypeParameter, (StringRef Name, DITypeRef Type),
+  DEFINE_MDNODE_GET(DITemplateTypeParameter, (StringRef Name, DIType *Type),
                     (Name, Type))
   DEFINE_MDNODE_GET(DITemplateTypeParameter, (MDString * Name, Metadata *Type),
                     (Name, Type))
 
   TempDITemplateTypeParameter clone() const { return cloneImpl(); }
 
   static bool classof(const Metadata *MD) {
     return MD->getMetadataID() == DITemplateTypeParameterKind;
   }
 };
 
 class DITemplateValueParameter : public DITemplateParameter {
   friend class LLVMContextImpl;
   friend class MDNode;
 
   DITemplateValueParameter(LLVMContext &Context, StorageType Storage,
                            unsigned Tag, ArrayRef<Metadata *> Ops)
       : DITemplateParameter(Context, DITemplateValueParameterKind, Storage, Tag,
                             Ops) {}
   ~DITemplateValueParameter() = default;
 
   static DITemplateValueParameter *getImpl(LLVMContext &Context, unsigned Tag,
-                                           StringRef Name, DITypeRef Type,
+                                           StringRef Name, DIType *Type,
                                            Metadata *Value, StorageType Storage,
                                            bool ShouldCreate = true) {
     return getImpl(Context, Tag, getCanonicalMDString(Context, Name), Type,
                    Value, Storage, ShouldCreate);
   }
   static DITemplateValueParameter *getImpl(LLVMContext &Context, unsigned Tag,
                                            MDString *Name, Metadata *Type,
                                            Metadata *Value, StorageType Storage,
                                            bool ShouldCreate = true);
 
   TempDITemplateValueParameter cloneImpl() const {
     return getTemporary(getContext(), getTag(), getName(), getType(),
                         getValue());
   }
 
 public:
-  DEFINE_MDNODE_GET(DITemplateValueParameter, (unsigned Tag, StringRef Name,
-                                               DITypeRef Type, Metadata *Value),
+  DEFINE_MDNODE_GET(DITemplateValueParameter,
+                    (unsigned Tag, StringRef Name, DIType *Type,
+                     Metadata *Value),
                     (Tag, Name, Type, Value))
   DEFINE_MDNODE_GET(DITemplateValueParameter, (unsigned Tag, MDString *Name,
                                                Metadata *Type, Metadata *Value),
                     (Tag, Name, Type, Value))
 
   TempDITemplateValueParameter clone() const { return cloneImpl(); }
 
   Metadata *getValue() const { return getOperand(2); }
DIVariable(LLVMContext &C, unsigned ID, StorageType Storage, unsigned Line,
         AlignInBits(AlignInBits) {}
   ~DIVariable() = default;
 
 public:
   unsigned getLine() const { return Line; }
   DIScope *getScope() const { return cast_or_null<DIScope>(getRawScope()); }
   StringRef getName() const { return getStringOperand(1); }
   DIFile *getFile() const { return cast_or_null<DIFile>(getRawFile()); }
-  DITypeRef getType() const { return DITypeRef(getRawType()); }
+  DIType *getType() const { return cast_or_null<DIType>(getRawType()); }
   uint32_t getAlignInBits() const { return AlignInBits; }
   uint32_t getAlignInBytes() const { return getAlignInBits() / CHAR_BIT; }
   /// Determines the size of the variable's type.
   Optional<uint64_t> getSizeInBits() const;
 
   /// Return the signedness of this variable's type, or None if this type is
   /// neither signed nor unsigned.
   Optional<DIBasicType::Signedness> getSignedness() const {
-    if (auto *BT = dyn_cast<DIBasicType>(getType().resolve()))
+    if (auto *BT = dyn_cast<DIBasicType>(getType()))
       return BT->getSignedness();
     return None;
   }
 
   StringRef getFilename() const {
     if (auto *F = getFile())
       return F->getFilename();
     return "";
DIGlobalVariable(LLVMContext &C, StorageType Storage, unsigned Line,
                    bool IsLocalToUnit, bool IsDefinition, uint32_t AlignInBits,
                    ArrayRef<Metadata *> Ops)
       : DIVariable(C, DIGlobalVariableKind, Storage, Line, Ops, AlignInBits),
         IsLocalToUnit(IsLocalToUnit), IsDefinition(IsDefinition) {}
   ~DIGlobalVariable() = default;
 
   static DIGlobalVariable *
   getImpl(LLVMContext &Context, DIScope *Scope, StringRef Name,
-          StringRef LinkageName, DIFile *File, unsigned Line, DITypeRef Type,
+          StringRef LinkageName, DIFile *File, unsigned Line, DIType *Type,
           bool IsLocalToUnit, bool IsDefinition,
           DIDerivedType *StaticDataMemberDeclaration, MDTuple *TemplateParams,
           uint32_t AlignInBits, StorageType Storage, bool ShouldCreate = true) {
     return getImpl(Context, Scope, getCanonicalMDString(Context, Name),
                    getCanonicalMDString(Context, LinkageName), File, Line, Type,
                    IsLocalToUnit, IsDefinition, StaticDataMemberDeclaration,
                    cast_or_null<Metadata>(TemplateParams), AlignInBits, Storage,
                    ShouldCreate);
return getTemporary(getContext(), getScope(), getName(), getLinkageName(),
                         getFile(), getLine(), getType(), isLocalToUnit(),
                         isDefinition(), getStaticDataMemberDeclaration(),
                         getTemplateParams(), getAlignInBits());
   }
 
 public:
   DEFINE_MDNODE_GET(DIGlobalVariable,
                     (DIScope * Scope, StringRef Name, StringRef LinkageName,
-                     DIFile *File, unsigned Line, DITypeRef Type,
+                     DIFile *File, unsigned Line, DIType *Type,
                      bool IsLocalToUnit, bool IsDefinition,
                      DIDerivedType *StaticDataMemberDeclaration,
                      MDTuple *TemplateParams, uint32_t AlignInBits),
                     (Scope, Name, LinkageName, File, Line, Type, IsLocalToUnit,
                      IsDefinition, StaticDataMemberDeclaration, TemplateParams,
                      AlignInBits))
   DEFINE_MDNODE_GET(DIGlobalVariable,
                     (Metadata * Scope, MDString *Name, MDString *LinkageName,
DILocalVariable(LLVMContext &C, StorageType Storage, unsigned Line,
       : DIVariable(C, DILocalVariableKind, Storage, Line, Ops, AlignInBits),
         Arg(Arg), Flags(Flags) {
     assert(Arg < (1 << 16) && "DILocalVariable: Arg out of range");
   }
   ~DILocalVariable() = default;
 
   static DILocalVariable *getImpl(LLVMContext &Context, DIScope *Scope,
                                   StringRef Name, DIFile *File, unsigned Line,
-                                  DITypeRef Type, unsigned Arg, DIFlags Flags,
+                                  DIType *Type, unsigned Arg, DIFlags Flags,
                                   uint32_t AlignInBits, StorageType Storage,
                                   bool ShouldCreate = true) {
     return getImpl(Context, Scope, getCanonicalMDString(Context, Name), File,
                    Line, Type, Arg, Flags, AlignInBits, Storage, ShouldCreate);
   }
   static DILocalVariable *getImpl(LLVMContext &Context, Metadata *Scope,
                                   MDString *Name, Metadata *File, unsigned Line,
                                   Metadata *Type, unsigned Arg, DIFlags Flags,
                                   uint32_t AlignInBits, StorageType Storage,
                                   bool ShouldCreate = true);
 
   TempDILocalVariable cloneImpl() const {
     return getTemporary(getContext(), getScope(), getName(), getFile(),
                         getLine(), getType(), getArg(), getFlags(),
                         getAlignInBits());
   }
 
 public:
   DEFINE_MDNODE_GET(DILocalVariable,
                     (DILocalScope * Scope, StringRef Name, DIFile *File,
-                     unsigned Line, DITypeRef Type, unsigned Arg,
-                     DIFlags Flags, uint32_t AlignInBits),
+                     unsigned Line, DIType *Type, unsigned Arg, DIFlags Flags,
+                     uint32_t AlignInBits),
                     (Scope, Name, File, Line, Type, Arg, Flags, AlignInBits))
   DEFINE_MDNODE_GET(DILocalVariable,
                     (Metadata * Scope, MDString *Name, Metadata *File,
                      unsigned Line, Metadata *Type, unsigned Arg,
                      DIFlags Flags, uint32_t AlignInBits),
                     (Scope, Name, File, Line, Type, Arg, Flags, AlignInBits))
 
   TempDILocalVariable clone() const { return cloneImpl(); }
DIObjCProperty(LLVMContext &C, StorageType Storage, unsigned Line,
       : DINode(C, DIObjCPropertyKind, Storage, dwarf::DW_TAG_APPLE_property,
                Ops),
         Line(Line), Attributes(Attributes) {}
   ~DIObjCProperty() = default;
 
   static DIObjCProperty *
   getImpl(LLVMContext &Context, StringRef Name, DIFile *File, unsigned Line,
           StringRef GetterName, StringRef SetterName, unsigned Attributes,
-          DITypeRef Type, StorageType Storage, bool ShouldCreate = true) {
+          DIType *Type, StorageType Storage, bool ShouldCreate = true) {
     return getImpl(Context, getCanonicalMDString(Context, Name), File, Line,
                    getCanonicalMDString(Context, GetterName),
                    getCanonicalMDString(Context, SetterName), Attributes, Type,
                    Storage, ShouldCreate);
   }
   static DIObjCProperty *getImpl(LLVMContext &Context, MDString *Name,
                                  Metadata *File, unsigned Line,
                                  MDString *GetterName, MDString *SetterName,
                                  unsigned Attributes, Metadata *Type,
                                  StorageType Storage, bool ShouldCreate = true);
 
   TempDIObjCProperty cloneImpl() const {
     return getTemporary(getContext(), getName(), getFile(), getLine(),
                         getGetterName(), getSetterName(), getAttributes(),
                         getType());
   }
 
 public:
   DEFINE_MDNODE_GET(DIObjCProperty,
                     (StringRef Name, DIFile *File, unsigned Line,
                      StringRef GetterName, StringRef SetterName,
-                     unsigned Attributes, DITypeRef Type),
+                     unsigned Attributes, DIType *Type),
                     (Name, File, Line, GetterName, SetterName, Attributes,
                      Type))
   DEFINE_MDNODE_GET(DIObjCProperty,
                     (MDString * Name, Metadata *File, unsigned Line,
                      MDString *GetterName, MDString *SetterName,
                      unsigned Attributes, Metadata *Type),
                     (Name, File, Line, GetterName, SetterName, Attributes,
                      Type))
 
   TempDIObjCProperty clone() const { return cloneImpl(); }
 
   unsigned getLine() const { return Line; }
   unsigned getAttributes() const { return Attributes; }
   StringRef getName() const { return getStringOperand(0); }
   DIFile *getFile() const { return cast_or_null<DIFile>(getRawFile()); }
   StringRef getGetterName() const { return getStringOperand(2); }
   StringRef getSetterName() const { return getStringOperand(3); }
-  DITypeRef getType() const { return DITypeRef(getRawType()); }
+  DIType *getType() const { return cast_or_null<DIType>(getRawType()); }
 
   StringRef getFilename() const {
     if (auto *F = getFile())
       return F->getFilename();
     return "";
   }
 
   StringRef getDirectory() const {
class DIImportedEntity : public DINode {
   unsigned Line;
 
   DIImportedEntity(LLVMContext &C, StorageType Storage, unsigned Tag,
                    unsigned Line, ArrayRef<Metadata *> Ops)
       : DINode(C, DIImportedEntityKind, Storage, Tag, Ops), Line(Line) {}
   ~DIImportedEntity() = default;
 
   static DIImportedEntity *getImpl(LLVMContext &Context, unsigned Tag,
-                                   DIScope *Scope, DINodeRef Entity,
-                                   DIFile *File, unsigned Line, StringRef Name,
+                                   DIScope *Scope, DINode *Entity, DIFile *File,
+                                   unsigned Line, StringRef Name,
                                    StorageType Storage,
                                    bool ShouldCreate = true) {
     return getImpl(Context, Tag, Scope, Entity, File, Line,
                    getCanonicalMDString(Context, Name), Storage, ShouldCreate);
   }
   static DIImportedEntity *getImpl(LLVMContext &Context, unsigned Tag,
                                    Metadata *Scope, Metadata *Entity,
                                    Metadata *File, unsigned Line,
                                    MDString *Name, StorageType Storage,
                                    bool ShouldCreate = true);
 
   TempDIImportedEntity cloneImpl() const {
     return getTemporary(getContext(), getTag(), getScope(), getEntity(),
                         getFile(), getLine(), getName());
   }
 
 public:
   DEFINE_MDNODE_GET(DIImportedEntity,
-                    (unsigned Tag, DIScope *Scope, DINodeRef Entity,
-                     DIFile *File, unsigned Line, StringRef Name = ""),
+                    (unsigned Tag, DIScope *Scope, DINode *Entity, DIFile *File,
+                     unsigned Line, StringRef Name = ""),
                     (Tag, Scope, Entity, File, Line, Name))
   DEFINE_MDNODE_GET(DIImportedEntity,
                     (unsigned Tag, Metadata *Scope, Metadata *Entity,
                      Metadata *File, unsigned Line, MDString *Name),
                     (Tag, Scope, Entity, File, Line, Name))
 
   TempDIImportedEntity clone() const { return cloneImpl(); }
 
   unsigned getLine() const { return Line; }
   DIScope *getScope() const { return cast_or_null<DIScope>(getRawScope()); }
-  DINodeRef getEntity() const { return DINodeRef(getRawEntity()); }
+  DINode *getEntity() const { return cast_or_null<DINode>(getRawEntity()); }
   StringRef getName() const { return getStringOperand(2); }
   DIFile *getFile() const { return cast_or_null<DIFile>(getRawFile()); }
 
   Metadata *getRawScope() const { return getOperand(0); }
   Metadata *getRawEntity() const { return getOperand(1); }
   MDString *getRawName() const { return getOperandAs<MDString>(2); }
   Metadata *getRawFile() const { return getOperand(3); }
 

lib/Bitcode/Reader/MetadataLoader.cpp

Metadata *BitcodeReaderMetadataList::upgradeTypeRefArray(Metadata *MaybeTuple) {
   return OldTypeRefs.Arrays.back().second.get();
 }
 
 Metadata *BitcodeReaderMetadataList::resolveTypeRefArray(Metadata *MaybeTuple) {
   auto *Tuple = dyn_cast_or_null<MDTuple>(MaybeTuple);
   if (!Tuple || Tuple->isDistinct())
     return MaybeTuple;
 
-  // Look through the DITypeRefArray, upgrading each DITypeRef.
+  // Look through the DITypeRefArray, upgrading each DIType *.
   SmallVector<Metadata *, 32> Ops;
   Ops.reserve(Tuple->getNumOperands());
   for (Metadata *MD : Tuple->operands())
     Ops.push_back(upgradeTypeRef(MD));
 
   return MDTuple::get(Context, Ops);
 }
 

lib/CodeGen/AsmPrinter/CodeViewDebug.h

class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
   void emitLexicalBlockList(ArrayRef<LexicalBlock *> Blocks,
                             const FunctionInfo& FI);
 
   /// Emit a lexical block scope and its children.
   void emitLexicalBlock(const LexicalBlock &Block, const FunctionInfo& FI);
 
   /// Translates the DIType to codeview if necessary and returns a type index
   /// for it.
-  codeview::TypeIndex getTypeIndex(DITypeRef TypeRef,
-                                   DITypeRef ClassTyRef = DITypeRef());
+  codeview::TypeIndex getTypeIndex(const DIType *Ty,
+                                   const DIType *ClassTy = nullptr);
 
   codeview::TypeIndex
   getTypeIndexForThisPtr(const DIDerivedType *PtrTy,
                          const DISubroutineType *SubroutineTy);
 
-  codeview::TypeIndex getTypeIndexForReferenceTo(DITypeRef TypeRef);
+  codeview::TypeIndex getTypeIndexForReferenceTo(const DIType *Ty);
 
   codeview::TypeIndex getMemberFunctionType(const DISubprogram *SP,
                                             const DICompositeType *Class);
 
   codeview::TypeIndex getScopeIndex(const DIScope *Scope);
 
   codeview::TypeIndex getVBPTypeIndex();
 
class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
   codeview::TypeIndex lowerTypeClass(const DICompositeType *Ty);
   codeview::TypeIndex lowerTypeUnion(const DICompositeType *Ty);
 
   /// Symbol records should point to complete types, but type records should
   /// always point to incomplete types to avoid cycles in the type graph. Only
   /// use this entry point when generating symbol records. The complete and
   /// incomplete type indices only differ for record types. All other types use
   /// the same index.
-  codeview::TypeIndex getCompleteTypeIndex(DITypeRef TypeRef);
+  codeview::TypeIndex getCompleteTypeIndex(const DIType *Ty);
 
   codeview::TypeIndex lowerCompleteTypeClass(const DICompositeType *Ty);
   codeview::TypeIndex lowerCompleteTypeUnion(const DICompositeType *Ty);
 
   struct TypeLoweringScope;
 
   void emitDeferredCompleteTypes();
 

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

static const DISubprogram *getQualifiedNameComponents(
     const DIScope *Scope, SmallVectorImpl<StringRef> &QualifiedNameComponents) {
   const DISubprogram *ClosestSubprogram = nullptr;
   while (Scope != nullptr) {
     if (ClosestSubprogram == nullptr)
       ClosestSubprogram = dyn_cast<DISubprogram>(Scope);
     StringRef ScopeName = getPrettyScopeName(Scope);
     if (!ScopeName.empty())
       QualifiedNameComponents.push_back(ScopeName);
-    Scope = Scope->getScope().resolve();
+    Scope = Scope->getScope();
   }
   return ClosestSubprogram;
 }
 
 static std::string getQualifiedName(ArrayRef<StringRef> QualifiedNameComponents,
                                     StringRef TypeName) {
   std::string FullyQualifiedName;
   for (StringRef QualifiedNameComponent :
~TypeLoweringScope() {
     if (CVD.TypeEmissionLevel == 1)
       CVD.emitDeferredCompleteTypes();
     --CVD.TypeEmissionLevel;
   }
   CodeViewDebug &CVD;
 };
 
 static std::string getFullyQualifiedName(const DIScope *Ty) {
-  const DIScope *Scope = Ty->getScope().resolve();
+  const DIScope *Scope = Ty->getScope();
   return getFullyQualifiedName(Scope, getPrettyScopeName(Ty));
 }
 
 TypeIndex CodeViewDebug::getScopeIndex(const DIScope *Scope) {
   // No scope means global scope and that uses the zero index.
   if (!Scope || isa<DIFile>(Scope))
     return TypeIndex();
 
TypeIndex CodeViewDebug::getFuncIdForSubprogram(const DISubprogram *SP) {
   auto I = TypeIndices.find({SP, nullptr});
   if (I != TypeIndices.end())
     return I->second;
 
   // The display name includes function template arguments. Drop them to match
   // MSVC.
   StringRef DisplayName = SP->getName().split('<').first;
 
-  const DIScope *Scope = SP->getScope().resolve();
+  const DIScope *Scope = SP->getScope();
   TypeIndex TI;
   if (const auto *Class = dyn_cast_or_null<DICompositeType>(Scope)) {
     // If the scope is a DICompositeType, then this must be a method. Member
     // function types take some special handling, and require access to the
     // subprogram.
     TypeIndex ClassType = getTypeIndex(Class);
     MemberFuncIdRecord MFuncId(ClassType, getMemberFunctionType(SP, Class),
                                DisplayName);

 static FunctionOptions
 getFunctionOptions(const DISubroutineType *Ty,
                    const DICompositeType *ClassTy = nullptr,
                    StringRef SPName = StringRef("")) {
   FunctionOptions FO = FunctionOptions::None;
   const DIType *ReturnTy = nullptr;
   if (auto TypeArray = Ty->getTypeArray()) {
     if (TypeArray.size())
-      ReturnTy = TypeArray[0].resolve();
+      ReturnTy = TypeArray[0];
   }
 
   if (auto *ReturnDCTy = dyn_cast_or_null<DICompositeType>(ReturnTy)) {
     if (isNonTrivial(ReturnDCTy))
       FO |= FunctionOptions::CxxReturnUdt;
   }
 
   // DISubroutineType is unnamed. Use DISubprogram's i.e. SPName in comparison.
void CodeViewDebug::emitDebugInfoForFunction(const Function *GV,
   if (SP->isThunk()) {
     emitDebugInfoForThunk(GV, FI, Fn);
     return;
   }
 
   // If we have a display name, build the fully qualified name by walking the
   // chain of scopes.
   if (!SP->getName().empty())
-    FuncName =
-        getFullyQualifiedName(SP->getScope().resolve(), SP->getName());
+    FuncName = getFullyQualifiedName(SP->getScope(), SP->getName());
 
   // If our DISubprogram name is empty, use the mangled name.
   if (FuncName.empty())
     FuncName = GlobalValue::dropLLVMManglingEscape(GV->getName());
 
   // Emit FPO data, but only on 32-bit x86. No other platforms use it.
   if (Triple(MMI->getModule()->getTargetTriple()).getArch() == Triple::x86)
     OS.EmitCVFPOData(Fn);

 }
 
 static bool shouldEmitUdt(const DIType *T) {
   if (!T)
     return false;
 
   // MSVC does not emit UDTs for typedefs that are scoped to classes.
   if (T->getTag() == dwarf::DW_TAG_typedef) {
-    if (DIScope *Scope = T->getScope().resolve()) {
+    if (DIScope *Scope = T->getScope()) {
       switch (Scope->getTag()) {
       case dwarf::DW_TAG_structure_type:
       case dwarf::DW_TAG_class_type:
       case dwarf::DW_TAG_union_type:
         return false;
       }
     }
   }
 
   while (true) {
     if (!T || T->isForwardDecl())
       return false;
 
     const DIDerivedType *DT = dyn_cast<DIDerivedType>(T);
     if (!DT)
       return true;
-    T = DT->getBaseType().resolve();
+    T = DT->getBaseType();
   }
   return true;
 }
 
 void CodeViewDebug::addToUDTs(const DIType *Ty) {
   // Don't record empty UDTs.
   if (Ty->getName().empty())
     return;
   if (!shouldEmitUdt(Ty))
     return;
 
   SmallVector<StringRef, 5> QualifiedNameComponents;
-  const DISubprogram *ClosestSubprogram = getQualifiedNameComponents(
-      Ty->getScope().resolve(), QualifiedNameComponents);
+  const DISubprogram *ClosestSubprogram =
+      getQualifiedNameComponents(Ty->getScope(), QualifiedNameComponents);
 
   std::string FullyQualifiedName =
       getQualifiedName(QualifiedNameComponents, getPrettyScopeName(Ty));
 
   if (ClosestSubprogram == nullptr) {
     GlobalUDTs.emplace_back(std::move(FullyQualifiedName), Ty);
   } else if (ClosestSubprogram == CurrentSubprogram) {
     LocalUDTs.emplace_back(std::move(FullyQualifiedName), Ty);
case dwarf::DW_TAG_unspecified_type:
     return TypeIndex::None();
   default:
     // Use the null type index.
     return TypeIndex();
   }
 }
 
 TypeIndex CodeViewDebug::lowerTypeAlias(const DIDerivedType *Ty) {
-  DITypeRef UnderlyingTypeRef = Ty->getBaseType();
-  TypeIndex UnderlyingTypeIndex = getTypeIndex(UnderlyingTypeRef);
+  TypeIndex UnderlyingTypeIndex = getTypeIndex(Ty->getBaseType());
   StringRef TypeName = Ty->getName();
 
   addToUDTs(Ty);
 
   if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::Int32Long) &&
       TypeName == "HRESULT")
     return TypeIndex(SimpleTypeKind::HResult);
   if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::UInt16Short) &&
       TypeName == "wchar_t")
     return TypeIndex(SimpleTypeKind::WideCharacter);
 
   return UnderlyingTypeIndex;
 }
 
 TypeIndex CodeViewDebug::lowerTypeArray(const DICompositeType *Ty) {
-  DITypeRef ElementTypeRef = Ty->getBaseType();
-  TypeIndex ElementTypeIndex = getTypeIndex(ElementTypeRef);
+  const DIType *ElementType = Ty->getBaseType();
+  TypeIndex ElementTypeIndex = getTypeIndex(ElementType);
   // IndexType is size_t, which depends on the bitness of the target.
   TypeIndex IndexType = getPointerSizeInBytes() == 8
                             ? TypeIndex(SimpleTypeKind::UInt64Quad)
                             : TypeIndex(SimpleTypeKind::UInt32Long);
 
-  uint64_t ElementSize = getBaseTypeSize(ElementTypeRef) / 8;
+  uint64_t ElementSize = getBaseTypeSize(ElementType) / 8;
 
   // Add subranges to array type.
   DINodeArray Elements = Ty->getElements();
   for (int i = Elements.size() - 1; i >= 0; --i) {
     const DINode *Element = Elements[i];
     assert(Element->getTag() == dwarf::DW_TAG_subrange_type);
 
     const DISubrange *Subrange = cast<DISubrange>(Element);
case dwarf::DW_TAG_restrict_type:
       // for __restrict in LF_MODIFIER records.
       PO |= PointerOptions::Restrict;
       break;
     default:
       IsModifier = false;
       break;
     }
     if (IsModifier)
-      BaseTy = cast<DIDerivedType>(BaseTy)->getBaseType().resolve();
+      BaseTy = cast<DIDerivedType>(BaseTy)->getBaseType();
   }
 
   // Check if the inner type will use an LF_POINTER record. If so, the
   // qualifiers will go in the LF_POINTER record. This comes up for types like
   // 'int *const' and 'int *__restrict', not the more common cases like 'const
   // char *'.
   if (BaseTy) {
     switch (BaseTy->getTag()) {
if (Mods == ModifierOptions::None)
     return ModifiedTI;
 
   ModifierRecord MR(ModifiedTI, Mods);
   return TypeTable.writeLeafType(MR);
 }
 
 TypeIndex CodeViewDebug::lowerTypeFunction(const DISubroutineType *Ty) {
   SmallVector<TypeIndex, 8> ReturnAndArgTypeIndices;
-  for (DITypeRef ArgTypeRef : Ty->getTypeArray())
-    ReturnAndArgTypeIndices.push_back(getTypeIndex(ArgTypeRef));
+  for (const DIType *ArgType : Ty->getTypeArray())
+    ReturnAndArgTypeIndices.push_back(getTypeIndex(ArgType));
 
   // MSVC uses type none for variadic argument.
   if (ReturnAndArgTypeIndices.size() > 1 &&
       ReturnAndArgTypeIndices.back() == TypeIndex::Void()) {
     ReturnAndArgTypeIndices.back() = TypeIndex::None();
   }
   TypeIndex ReturnTypeIndex = TypeIndex::Void();
   ArrayRef<TypeIndex> ArgTypeIndices = None;
TypeIndex CodeViewDebug::lowerTypeMemberFunction(const DISubroutineType *Ty,
   }
 
   // If the first argument is a pointer type and this isn't a static method,
   // treat it as the special 'this' parameter, which is encoded separately from
   // the arguments.
   TypeIndex ThisTypeIndex;
   if (!IsStaticMethod && ReturnAndArgs.size() > Index) {
     if (const DIDerivedType *PtrTy =
-            dyn_cast_or_null<DIDerivedType>(ReturnAndArgs[Index].resolve())) {
+            dyn_cast_or_null<DIDerivedType>(ReturnAndArgs[Index])) {
       if (PtrTy->getTag() == dwarf::DW_TAG_pointer_type) {
         ThisTypeIndex = getTypeIndexForThisPtr(PtrTy, Ty);
         Index++;
       }
     }
   }
 
   while (Index < ReturnAndArgs.size())
static ClassOptions getCommonClassOptions(const DICompositeType *Ty) {
   // appear to give every type a linkage name, which may be problematic for us.
   // FIXME: Investigate the consequences of not following them here.
   if (!Ty->getIdentifier().empty())
     CO |= ClassOptions::HasUniqueName;
 
   // Put the Nested flag on a type if it appears immediately inside a tag type.
   // Do not walk the scope chain. Do not attempt to compute ContainsNestedClass
   // here. That flag is only set on definitions, and not forward declarations.
-  const DIScope *ImmediateScope = Ty->getScope().resolve();
+  const DIScope *ImmediateScope = Ty->getScope();
   if (ImmediateScope && isa<DICompositeType>(ImmediateScope))
     CO |= ClassOptions::Nested;
 
   // Put the Scoped flag on function-local types. MSVC puts this flag for enum
   // type only when it has an immediate function scope. Clang never puts enums
   // inside DILexicalBlock scopes. Enum types, as generated by clang, are
   // always in function, class, or file scopes.
   if (Ty->getTag() == dwarf::DW_TAG_enumeration_type) {
     if (ImmediateScope && isa<DISubprogram>(ImmediateScope))
       CO |= ClassOptions::Scoped;
   } else {
     for (const DIScope *Scope = ImmediateScope; Scope != nullptr;
-         Scope = Scope->getScope().resolve()) {
+         Scope = Scope->getScope()) {
       if (isa<DISubprogram>(Scope)) {
         CO |= ClassOptions::Scoped;
         break;
       }
     }
   }
 
   return CO;
void CodeViewDebug::collectMemberInfo(ClassInfo &Info,
   }
 
   // An unnamed member may represent a nested struct or union. Attempt to
   // interpret the unnamed member as a DICompositeType possibly wrapped in
   // qualifier types. Add all the indirect fields to the current record if that
   // succeeds, and drop the member if that fails.
   assert((DDTy->getOffsetInBits() % 8) == 0 && "Unnamed bitfield member!");
   uint64_t Offset = DDTy->getOffsetInBits();
-  const DIType *Ty = DDTy->getBaseType().resolve();
+  const DIType *Ty = DDTy->getBaseType();
   bool FullyResolved = false;
   while (!FullyResolved) {
     switch (Ty->getTag()) {
     case dwarf::DW_TAG_const_type:
     case dwarf::DW_TAG_volatile_type:
       // FIXME: we should apply the qualifier types to the indirect fields
       // rather than dropping them.
-      Ty = cast<DIDerivedType>(Ty)->getBaseType().resolve();
+      Ty = cast<DIDerivedType>(Ty)->getBaseType();
       break;
     default:
       FullyResolved = true;
       break;
     }
   }
 
   const DICompositeType *DCTy = dyn_cast<DICompositeType>(Ty);
else {
 
       OverloadedMethodRecord OMR(Methods.size(), MethodList, Name);
       ContinuationBuilder.writeMemberType(OMR);
     }
   }
 
   // Create nested classes.
   for (const DIType *Nested : Info.NestedTypes) {
-    NestedTypeRecord R(getTypeIndex(DITypeRef(Nested)), Nested->getName());
+    NestedTypeRecord R(getTypeIndex(Nested), Nested->getName());
     ContinuationBuilder.writeMemberType(R);
     MemberCount++;
   }
 
   TypeIndex FieldTI = TypeTable.insertRecord(ContinuationBuilder);
   return std::make_tuple(FieldTI, Info.VShapeTI, MemberCount,
                          !Info.NestedTypes.empty());
 }
if (!VBPType.getIndex()) {
     PointerOptions PO = PointerOptions::None;
     PointerRecord PR(ModifiedTI, PK, PM, PO, getPointerSizeInBytes());
     VBPType = TypeTable.writeLeafType(PR);
   }
 
   return VBPType;
 }
 
-TypeIndex CodeViewDebug::getTypeIndex(DITypeRef TypeRef, DITypeRef ClassTyRef) {
-  const DIType *Ty = TypeRef.resolve();
-  const DIType *ClassTy = ClassTyRef.resolve();
-
+TypeIndex CodeViewDebug::getTypeIndex(const DIType *Ty, const DIType *ClassTy) {
   // The null DIType is the void type. Don't try to hash it.
   if (!Ty)
     return TypeIndex::Void();
 
   // Check if we've already translated this type. Don't try to do a
   // get-or-create style insertion that caches the hash lookup across the
   // lowerType call. It will update the TypeIndices map.
   auto I = TypeIndices.find({Ty, ClassTy});
CodeViewDebug::getTypeIndexForThisPtr(const DIDerivedType *PtrTy,
   if (I != TypeIndices.end())
     return I->second;
 
   TypeLoweringScope S(*this);
   TypeIndex TI = lowerTypePointer(PtrTy, Options);
   return recordTypeIndexForDINode(PtrTy, TI, SubroutineTy);
 }
 
-TypeIndex CodeViewDebug::getTypeIndexForReferenceTo(DITypeRef TypeRef) {
-  DIType *Ty = TypeRef.resolve();
+TypeIndex CodeViewDebug::getTypeIndexForReferenceTo(const DIType *Ty) {
   PointerRecord PR(getTypeIndex(Ty),
                    getPointerSizeInBytes() == 8 ? PointerKind::Near64
                                                 : PointerKind::Near32,
                    PointerMode::LValueReference, PointerOptions::None,
                    Ty->getSizeInBits() / 8);
   return TypeTable.writeLeafType(PR);
 }
 
-TypeIndex CodeViewDebug::getCompleteTypeIndex(DITypeRef TypeRef) {
-  const DIType *Ty = TypeRef.resolve();
-
+TypeIndex CodeViewDebug::getCompleteTypeIndex(const DIType *Ty) {
   // The null DIType is the void type. Don't try to hash it.
   if (!Ty)
     return TypeIndex::Void();
 
   // Look through typedefs when getting the complete type index. Call
   // getTypeIndex on the typdef to ensure that any UDTs are accumulated and are
   // emitted only once.
   if (Ty->getTag() == dwarf::DW_TAG_typedef)
     (void)getTypeIndex(Ty);
   while (Ty->getTag() == dwarf::DW_TAG_typedef)
-    Ty = cast<DIDerivedType>(Ty)->getBaseType().resolve();
+    Ty = cast<DIDerivedType>(Ty)->getBaseType();
 
   // If this is a non-record type, the complete type index is the same as the
   // normal type index. Just call getTypeIndex.
   switch (Ty->getTag()) {
   case dwarf::DW_TAG_class_type:
   case dwarf::DW_TAG_structure_type:
   case dwarf::DW_TAG_union_type:
     break;

lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp

DebugHandlerBase::getFunctionLocalOffsetAfterInsn(const MachineInstr *MI) {
   MCSymbol *AfterInsn = getLabelAfterInsn(MI);
   assert(AfterInsn && "Expected label after instruction");
   const auto *AfterRef = MCSymbolRefExpr::create(AfterInsn, MC);
 
   return MCBinaryExpr::createSub(AfterRef, StartRef, MC);
 }
 
 /// If this type is derived from a base type then return base type size.
-uint64_t DebugHandlerBase::getBaseTypeSize(const DITypeRef TyRef) {
-  DIType *Ty = TyRef.resolve();
+uint64_t DebugHandlerBase::getBaseTypeSize(const DIType *Ty) {
   assert(Ty);
-  DIDerivedType *DDTy = dyn_cast<DIDerivedType>(Ty);
+  const DIDerivedType *DDTy = dyn_cast<DIDerivedType>(Ty);
   if (!DDTy)
     return Ty->getSizeInBits();
 
   unsigned Tag = DDTy->getTag();
 
   if (Tag != dwarf::DW_TAG_member && Tag != dwarf::DW_TAG_typedef &&
       Tag != dwarf::DW_TAG_const_type && Tag != dwarf::DW_TAG_volatile_type &&
       Tag != dwarf::DW_TAG_restrict_type && Tag != dwarf::DW_TAG_atomic_type)
     return DDTy->getSizeInBits();
 
-  DIType *BaseType = DDTy->getBaseType().resolve();
+  DIType *BaseType = DDTy->getBaseType();
 
   if (!BaseType)
     return 0;
 
   // If this is a derived type, go ahead and get the base type, unless it's a
   // reference then it's just the size of the field. Pointer types have no need
   // of this since they're a different type of qualification on the type.
   if (BaseType->getTag() == dwarf::DW_TAG_reference_type ||

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
     const DIGlobalVariable *GV, ArrayRef<GlobalExpr> GlobalExprs) {
   // Check for pre-existence.
   if (DIE *Die = getDIE(GV))
     return Die;
 
   assert(GV);
 
   auto *GVContext = GV->getScope();
-  auto *GTy = DD->resolve(GV->getType());
+  const DIType *GTy = GV->getType();
 
   // Construct the context before querying for the existence of the DIE in
   // case such construction creates the DIE.
   auto *CB = GVContext ? dyn_cast<DICommonBlock>(GVContext) : nullptr;
   DIE *ContextDIE = CB ? getOrCreateCommonBlock(CB, GlobalExprs)
     : getOrCreateContextDIE(GVContext);
 
   // Add to map.
   DIE *VariableDIE = &createAndAddDIE(GV->getTag(), *ContextDIE, GV);
   DIScope *DeclContext;
   if (auto *SDMDecl = GV->getStaticDataMemberDeclaration()) {
-    DeclContext = resolve(SDMDecl->getScope());
+    DeclContext = SDMDecl->getScope();
     assert(SDMDecl->isStaticMember() && "Expected static member decl");
     assert(GV->isDefinition());
     // We need the declaration DIE that is in the static member's class.
     DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl);
     addDIEEntry(*VariableDIE, dwarf::DW_AT_specification, *VariableSpecDIE);
     // If the global variable's type is different from the one in the class
     // member type, assume that it's more specific and also emit it.
-    if (GTy != DD->resolve(SDMDecl->getBaseType()))
+    if (GTy != SDMDecl->getBaseType())
       addType(*VariableDIE, GTy);
   } else {
     DeclContext = GV->getScope();
     // Add name and type.
     addString(*VariableDIE, dwarf::DW_AT_name, GV->getDisplayName());
     addType(*VariableDIE, GTy);
 
     // Add scoping info.
void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
   // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
   // the important distinction that the debug node is not associated with the
   // DIE (since the debug node will be associated with the concrete DIE, if
   // any). It could be refactored to some common utility function.
   else if (auto *SPDecl = SP->getDeclaration()) {
     ContextDIE = &getUnitDie();
     getOrCreateSubprogramDIE(SPDecl);
   } else {
-    ContextDIE = getOrCreateContextDIE(resolve(SP->getScope()));
+    ContextDIE = getOrCreateContextDIE(SP->getScope());
     // The scope may be shared with a subprogram that has already been
     // constructed in another CU, in which case we need to construct this
     // subprogram in the same CU.
     ContextCU = DD->lookupCU(ContextDIE->getUnitDie());
   }
 
   // Passing null as the associated node because the abstract definition
   // shouldn't be found by lookup.
DIE &DwarfCompileUnit::constructCallSiteEntryDIE(DIE &ScopeDIE,
   return CallSiteDIE;
 }
 
 DIE *DwarfCompileUnit::constructImportedEntityDIE(
     const DIImportedEntity *Module) {
   DIE *IMDie = DIE::get(DIEValueAllocator, (dwarf::Tag)Module->getTag());
   insertDIE(Module, IMDie);
   DIE *EntityDie;
-  auto *Entity = resolve(Module->getEntity());
+  auto *Entity = Module->getEntity();
   if (auto *NS = dyn_cast<DINamespace>(Entity))
     EntityDie = getOrCreateNameSpace(NS);
   else if (auto *M = dyn_cast<DIModule>(Entity))
     EntityDie = getOrCreateModule(M);
   else if (auto *SP = dyn_cast<DISubprogram>(Entity))
     EntityDie = getOrCreateSubprogramDIE(SP);
   else if (auto *T = dyn_cast<DIType>(Entity))
     EntityDie = getOrCreateTypeDIE(T);
void DwarfCompileUnit::addAddressExpr(DIE &Die, dwarf::Attribute Attribute,
                                       const MCExpr *Expr) {
   Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
                DIEExpr(Expr));
 }
 
 void DwarfCompileUnit::applySubprogramAttributesToDefinition(
     const DISubprogram *SP, DIE &SPDie) {
   auto *SPDecl = SP->getDeclaration();
-  auto *Context = resolve(SPDecl ? SPDecl->getScope() : SP->getScope());
+  auto *Context = SPDecl ? SPDecl->getScope() : SP->getScope();
   applySubprogramAttributes(SP, SPDie, includeMinimalInlineScopes());
   addGlobalName(SP->getName(), SPDie, Context);
 }
 
 bool DwarfCompileUnit::isDwoUnit() const {
   return DD->useSplitDwarf() && Skeleton;
 }
 

lib/CodeGen/AsmPrinter/DwarfDebug.h

public:
   }
 
   bool isBlockByrefVariable() const;
   const DIType *getType() const;
 
   static bool classof(const DbgEntity *N) {
     return N->getDbgEntityID() == DbgVariableKind;
   }
-
-private:
-  template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
-    return Ref.resolve();
-  }
 };
 
 //===----------------------------------------------------------------------===//
 /// This class is used to track label information.
 ///
 /// Labels are collected from \c DBG_LABEL instructions.
 class DbgLabel : public DbgEntity {
   const MCSymbol *Sym;                  /// Symbol before DBG_LABEL instruction.
public:
   /// Translate tag to proper Dwarf tag.
   dwarf::Tag getTag() const {
     return dwarf::DW_TAG_label;
   }
 
   static bool classof(const DbgEntity *N) {
     return N->getDbgEntityID() == DbgLabelKind;
   }
-
-private:
-  template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
-    return Ref.resolve();
-  }
 };
 
 /// Helper used to pair up a symbol and its DWARF compile unit.
 struct SymbolCU {
   SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
 
   const MCSymbol *Sym;
   DwarfCompileUnit *CU;
public:
   void emitDebugLocEntry(ByteStreamer &Streamer,
                          const DebugLocStream::Entry &Entry,
                          const DwarfCompileUnit *CU);
 
   /// Emit the location for a debug loc entry, including the size header.
   void emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry,
                                  const DwarfCompileUnit *CU);
 
-  /// Find the MDNode for the given reference.
-  template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
-    return Ref.resolve();
-  }
-
   void addSubprogramNames(const DICompileUnit &CU, const DISubprogram *SP,
                           DIE &Die);
 
   AddressPool &getAddressPool() { return AddrPool; }
 
   void addAccelName(const DICompileUnit &CU, StringRef Name, const DIE &Die);
 
   void addAccelObjC(const DICompileUnit &CU, StringRef Name, const DIE &Die);

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

 bool DebugLocDwarfExpression::isFrameRegister(const TargetRegisterInfo &TRI,
                                               unsigned MachineReg) {
   // This information is not available while emitting .debug_loc entries.
   return false;
 }
 
 bool DbgVariable::isBlockByrefVariable() const {
   assert(getVariable() && "Invalid complex DbgVariable!");
-  return getVariable()->getType().resolve()->isBlockByrefStruct();
+  return getVariable()->getType()->isBlockByrefStruct();
 }
 
 const DIType *DbgVariable::getType() const {
-  DIType *Ty = getVariable()->getType().resolve();
+  DIType *Ty = getVariable()->getType();
   // FIXME: isBlockByrefVariable should be reformulated in terms of complex
   // addresses instead.
   if (Ty->isBlockByrefStruct()) {
     /* Byref variables, in Blocks, are declared by the programmer as
        "SomeType VarName;", but the compiler creates a
        __Block_byref_x_VarName struct, and gives the variable VarName
        either the struct, or a pointer to the struct, as its type.  This
        is necessary for various behind-the-scenes things the compiler
/* Byref variables, in Blocks, are declared by the programmer as
        side, the Debug Information Entry for the variable VarName needs to
        have a DW_AT_location that tells the debugger how to unwind through
        the pointers and __Block_byref_x_VarName struct to find the actual
        value of the variable.  The function addBlockByrefType does this.  */
     DIType *subType = Ty;
     uint16_t tag = Ty->getTag();
 
     if (tag == dwarf::DW_TAG_pointer_type)
-      subType = resolve(cast<DIDerivedType>(Ty)->getBaseType());
+      subType = cast<DIDerivedType>(Ty)->getBaseType();
 
     auto Elements = cast<DICompositeType>(subType)->getElements();
     for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
       auto *DT = cast<DIDerivedType>(Elements[i]);
       if (getName() == DT->getName())
-        return resolve(DT->getBaseType());
+        return DT->getBaseType();
     }
   }
   return Ty;
 }
 
 ArrayRef<DbgVariable::FrameIndexExpr> DbgVariable::getFrameIndexExprs() const {
   if (FrameIndexExprs.size() == 1)
     return FrameIndexExprs;

lib/CodeGen/AsmPrinter/DwarfUnit.h

protected:
 
   /// Create new static data member DIE.
   DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT);
 
   /// Look up the source ID for the given file. If none currently exists,
   /// create a new ID and insert it in the line table.
   virtual unsigned getOrCreateSourceID(const DIFile *File) = 0;
 
-  /// Look in the DwarfDebug map for the MDNode that corresponds to the
-  /// reference.
-  template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
-    return Ref.resolve();
-  }
-
   /// Emit the common part of the header for this unit.
   void emitCommonHeader(bool UseOffsets, dwarf::UnitType UT);
 
 private:
   void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy);
   void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy);
   void constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy);
   void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy);

lib/CodeGen/AsmPrinter/DwarfUnit.cpp

if (auto *DTy = dyn_cast<DIDerivedType>(Ty)) {
     if (T == dwarf::DW_TAG_pointer_type ||
         T == dwarf::DW_TAG_ptr_to_member_type ||
         T == dwarf::DW_TAG_reference_type ||
         T == dwarf::DW_TAG_rvalue_reference_type)
       return true;
     assert(T == dwarf::DW_TAG_typedef || T == dwarf::DW_TAG_const_type ||
            T == dwarf::DW_TAG_volatile_type ||
            T == dwarf::DW_TAG_restrict_type || T == dwarf::DW_TAG_atomic_type);
-    DITypeRef Deriv = DTy->getBaseType();
-    assert(Deriv && "Expected valid base type");
-    return isUnsignedDIType(DD, DD->resolve(Deriv));
+    assert(DTy->getBaseType() && "Expected valid base type");
+    return isUnsignedDIType(DD, DTy->getBaseType());
   }
 
   auto *BTy = cast<DIBasicType>(Ty);
   unsigned Encoding = BTy->getEncoding();
   assert((Encoding == dwarf::DW_ATE_unsigned ||
           Encoding == dwarf::DW_ATE_unsigned_char ||
           Encoding == dwarf::DW_ATE_signed ||
           Encoding == dwarf::DW_ATE_signed_char ||
DIE *DwarfUnit::getOrCreateContextDIE(const DIScope *Context) {
   if (auto *SP = dyn_cast<DISubprogram>(Context))
     return getOrCreateSubprogramDIE(SP);
   if (auto *M = dyn_cast<DIModule>(Context))
     return getOrCreateModule(M);
   return getDIE(Context);
 }
 
 DIE *DwarfUnit::createTypeDIE(const DICompositeType *Ty) {
-  auto *Context = resolve(Ty->getScope());
+  auto *Context = Ty->getScope();
   DIE *ContextDIE = getOrCreateContextDIE(Context);
 
   if (DIE *TyDIE = getDIE(Ty))
     return TyDIE;
 
   // Create new type.
   DIE &TyDIE = createAndAddDIE(Ty->getTag(), *ContextDIE, Ty);
 

 DIE *DwarfUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
   if (!TyNode)
     return nullptr;
 
   auto *Ty = cast<DIType>(TyNode);
 
   // DW_TAG_restrict_type is not supported in DWARF2
   if (Ty->getTag() == dwarf::DW_TAG_restrict_type && DD->getDwarfVersion() <= 2)
-    return getOrCreateTypeDIE(resolve(cast<DIDerivedType>(Ty)->getBaseType()));
+    return getOrCreateTypeDIE(cast<DIDerivedType>(Ty)->getBaseType());
 
   // DW_TAG_atomic_type is not supported in DWARF < 5
   if (Ty->getTag() == dwarf::DW_TAG_atomic_type && DD->getDwarfVersion() < 5)
-    return getOrCreateTypeDIE(resolve(cast<DIDerivedType>(Ty)->getBaseType()));
+    return getOrCreateTypeDIE(cast<DIDerivedType>(Ty)->getBaseType());
 
   // Construct the context before querying for the existence of the DIE in case
   // such construction creates the DIE.
-  auto *Context = resolve(Ty->getScope());
+  auto *Context = Ty->getScope();
   DIE *ContextDIE = getOrCreateContextDIE(Context);
   assert(ContextDIE);
 
   if (DIE *TyDIE = getDIE(Ty))
     return TyDIE;
 
   return static_cast<DwarfUnit *>(ContextDIE->getUnit())
       ->createTypeDIE(Context, *ContextDIE, Ty);
std::string DwarfUnit::getParentContextString(const DIScope *Context) const {
   // FIXME: Decide whether to implement this for non-C++ languages.
   if (getLanguage() != dwarf::DW_LANG_C_plus_plus)
     return "";
 
   std::string CS;
   SmallVector<const DIScope *, 1> Parents;
   while (!isa<DICompileUnit>(Context)) {
     Parents.push_back(Context);
-    if (Context->getScope())
-      Context = resolve(Context->getScope());
+    if (const DIScope *S = Context->getScope())
+      Context = S;
     else
       // Structure, etc types will have a NULL context if they're at the top
       // level.
       break;
   }
 
   // Reverse iterate over our list to go from the outermost construct to the
   // innermost.

 
 void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy) {
   // Get core information.
   StringRef Name = DTy->getName();
   uint64_t Size = DTy->getSizeInBits() >> 3;
   uint16_t Tag = Buffer.getTag();
 
   // Map to main type, void will not have a type.
-  const DIType *FromTy = resolve(DTy->getBaseType());
+  const DIType *FromTy = DTy->getBaseType();
   if (FromTy)
     addType(Buffer, FromTy);
 
   // Add name if not anonymous or intermediate type.
   if (!Name.empty())
     addString(Buffer, dwarf::DW_AT_name, Name);
 
   // Add size if non-zero (derived types might be zero-sized.)
   if (Size && Tag != dwarf::DW_TAG_pointer_type
            && Tag != dwarf::DW_TAG_ptr_to_member_type
            && Tag != dwarf::DW_TAG_reference_type
            && Tag != dwarf::DW_TAG_rvalue_reference_type)
     addUInt(Buffer, dwarf::DW_AT_byte_size, None, Size);
 
   if (Tag == dwarf::DW_TAG_ptr_to_member_type)
-    addDIEEntry(
-        Buffer, dwarf::DW_AT_containing_type,
-        *getOrCreateTypeDIE(resolve(cast<DIDerivedType>(DTy)->getClassType())));
+    addDIEEntry(Buffer, dwarf::DW_AT_containing_type,
+                *getOrCreateTypeDIE(cast<DIDerivedType>(DTy)->getClassType()));
   // Add source line info if available and TyDesc is not a forward declaration.
   if (!DTy->isForwardDecl())
     addSourceLine(Buffer, DTy);
 
   // If DWARF address space value is other than None, add it for pointer and
   // reference types as DW_AT_address_class.
   if (DTy->getDWARFAddressSpace() && (Tag == dwarf::DW_TAG_pointer_type ||
                                       Tag == dwarf::DW_TAG_reference_type))
     addUInt(Buffer, dwarf::DW_AT_address_class, dwarf::DW_FORM_data4,
             DTy->getDWARFAddressSpace().getValue());
 }
 
 void DwarfUnit::constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args) {
   for (unsigned i = 1, N = Args.size(); i < N; ++i) {
-    const DIType *Ty = resolve(Args[i]);
+    const DIType *Ty = Args[i];
     if (!Ty) {
       assert(i == N-1 && "Unspecified parameter must be the last argument");
       createAndAddDIE(dwarf::DW_TAG_unspecified_parameters, Buffer);
     } else {
       DIE &Arg = createAndAddDIE(dwarf::DW_TAG_formal_parameter, Buffer);
       addType(Arg, Ty);
       if (Ty->isArtificial())
         addFlag(Arg, dwarf::DW_AT_artificial);
     }
   }
 }
 
 void DwarfUnit::constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy) {
   // Add return type.  A void return won't have a type.
   auto Elements = cast<DISubroutineType>(CTy)->getTypeArray();
   if (Elements.size())
-    if (auto RTy = resolve(Elements[0]))
+    if (auto RTy = Elements[0])
       addType(Buffer, RTy);
 
   bool isPrototyped = true;
   if (Elements.size() == 2 && !Elements[1])
     isPrototyped = false;
 
   constructSubprogramArguments(Buffer, Elements);
 
case dwarf::DW_TAG_class_type: {
     for (const auto *Element : Elements) {
       if (!Element)
         continue;
       if (auto *SP = dyn_cast<DISubprogram>(Element))
         getOrCreateSubprogramDIE(SP);
       else if (auto *DDTy = dyn_cast<DIDerivedType>(Element)) {
         if (DDTy->getTag() == dwarf::DW_TAG_friend) {
           DIE &ElemDie = createAndAddDIE(dwarf::DW_TAG_friend, Buffer);
-          addType(ElemDie, resolve(DDTy->getBaseType()), dwarf::DW_AT_friend);
+          addType(ElemDie, DDTy->getBaseType(), dwarf::DW_AT_friend);
         } else if (DDTy->isStaticMember()) {
           getOrCreateStaticMemberDIE(DDTy);
         } else if (Tag == dwarf::DW_TAG_variant_part) {
           // When emitting a variant part, wrap each member in
           // DW_TAG_variant.
           DIE &Variant = createAndAddDIE(dwarf::DW_TAG_variant, Buffer);
           if (const ConstantInt *CI =
               dyn_cast_or_null<ConstantInt>(DDTy->getDiscriminantValue())) {
-            if (isUnsignedDIType(DD, resolve(Discriminator->getBaseType())))
+            if (isUnsignedDIType(DD, Discriminator->getBaseType()))
               addUInt(Variant, dwarf::DW_AT_discr_value, None, CI->getZExtValue());
             else
               addSInt(Variant, dwarf::DW_AT_discr_value, None, CI->getSExtValue());
           }
           constructMemberDIE(Variant, DDTy);
         } else {
           constructMemberDIE(Buffer, DDTy);
         }
       } else if (auto *Property = dyn_cast<DIObjCProperty>(Element)) {
         DIE &ElemDie = createAndAddDIE(Property->getTag(), Buffer);
         StringRef PropertyName = Property->getName();
         addString(ElemDie, dwarf::DW_AT_APPLE_property_name, PropertyName);
         if (Property->getType())
-          addType(ElemDie, resolve(Property->getType()));
+          addType(ElemDie, Property->getType());
         addSourceLine(ElemDie, Property);
         StringRef GetterName = Property->getGetterName();
         if (!GetterName.empty())
           addString(ElemDie, dwarf::DW_AT_APPLE_property_getter, GetterName);
         StringRef SetterName = Property->getSetterName();
         if (!SetterName.empty())
           addString(ElemDie, dwarf::DW_AT_APPLE_property_setter, SetterName);
         if (unsigned PropertyAttributes = Property->getAttributes())
case dwarf::DW_TAG_class_type: {
 
     if (CTy->isAppleBlockExtension())
       addFlag(Buffer, dwarf::DW_AT_APPLE_block);
 
     // This is outside the DWARF spec, but GDB expects a DW_AT_containing_type
     // inside C++ composite types to point to the base class with the vtable.
     // Rust uses DW_AT_containing_type to link a vtable to the type
     // for which it was created.
-    if (auto *ContainingType = resolve(CTy->getVTableHolder()))
+    if (auto *ContainingType = CTy->getVTableHolder())
       addDIEEntry(Buffer, dwarf::DW_AT_containing_type,
                   *getOrCreateTypeDIE(ContainingType));
 
     if (CTy->isObjcClassComplete())
       addFlag(Buffer, dwarf::DW_AT_APPLE_objc_complete_type);
 
     // Add template parameters to a class, structure or union types.
     // FIXME: The support isn't in the metadata for this yet.

 }
 
 void DwarfUnit::constructTemplateTypeParameterDIE(
     DIE &Buffer, const DITemplateTypeParameter *TP) {
   DIE &ParamDIE =
       createAndAddDIE(dwarf::DW_TAG_template_type_parameter, Buffer);
   // Add the type if it exists, it could be void and therefore no type.
   if (TP->getType())
-    addType(ParamDIE, resolve(TP->getType()));
+    addType(ParamDIE, TP->getType());
   if (!TP->getName().empty())
     addString(ParamDIE, dwarf::DW_AT_name, TP->getName());
 }
 
 void DwarfUnit::constructTemplateValueParameterDIE(
     DIE &Buffer, const DITemplateValueParameter *VP) {
   DIE &ParamDIE = createAndAddDIE(VP->getTag(), Buffer);
 
   // Add the type if there is one, template template and template parameter
   // packs will not have a type.
   if (VP->getTag() == dwarf::DW_TAG_template_value_parameter)
-    addType(ParamDIE, resolve(VP->getType()));
+    addType(ParamDIE, VP->getType());
   if (!VP->getName().empty())
     addString(ParamDIE, dwarf::DW_AT_name, VP->getName());
   if (Metadata *Val = VP->getValue()) {
     if (ConstantInt *CI = mdconst::dyn_extract<ConstantInt>(Val))
-      addConstantValue(ParamDIE, CI, resolve(VP->getType()));
+      addConstantValue(ParamDIE, CI, VP->getType());
     else if (GlobalValue *GV = mdconst::dyn_extract<GlobalValue>(Val)) {
       // We cannot describe the location of dllimport'd entities: the
       // computation of their address requires loads from the IAT.
       if (!GV->hasDLLImportStorageClass()) {
         // For declaration non-type template parameters (such as global values
         // and functions)
         DIELoc *Loc = new (DIEValueAllocator) DIELoc;
         addOpAddress(*Loc, Asm->getSymbol(GV));
DIE *DwarfUnit::getOrCreateModule(const DIModule *M) {
   return &MDie;
 }
 
 DIE *DwarfUnit::getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal) {
   // Construct the context before querying for the existence of the DIE in case
   // such construction creates the DIE (as is the case for member function
   // declarations).
   DIE *ContextDIE =
-      Minimal ? &getUnitDie() : getOrCreateContextDIE(resolve(SP->getScope()));
+      Minimal ? &getUnitDie() : getOrCreateContextDIE(SP->getScope());
 
   if (DIE *SPDie = getDIE(SP))
     return SPDie;
 
   if (auto *SPDecl = SP->getDeclaration()) {
     if (!Minimal) {
       // Add subprogram definitions to the CU die directly.
       ContextDIE = &getUnitDie();
void DwarfUnit::applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
 
   // Add a DW_AT_calling_convention if this has an explicit convention.
   if (CC && CC != dwarf::DW_CC_normal)
     addUInt(SPDie, dwarf::DW_AT_calling_convention, dwarf::DW_FORM_data1, CC);
 
   // Add a return type. If this is a type like a C/C++ void type we don't add a
   // return type.
   if (Args.size())
-    if (auto Ty = resolve(Args[0]))
+    if (auto Ty = Args[0])
       addType(SPDie, Ty);
 
   unsigned VK = SP->getVirtuality();
   if (VK) {
     addUInt(SPDie, dwarf::DW_AT_virtuality, dwarf::DW_FORM_data1, VK);
     if (SP->getVirtualIndex() != -1u) {
       DIELoc *Block = getDIELoc();
       addUInt(*Block, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
       addUInt(*Block, dwarf::DW_FORM_udata, SP->getVirtualIndex());
       addBlock(SPDie, dwarf::DW_AT_vtable_elem_location, Block);
     }
-    ContainingTypeMap.insert(
-        std::make_pair(&SPDie, resolve(SP->getContainingType())));
+    ContainingTypeMap.insert(std::make_pair(&SPDie, SP->getContainingType()));
   }
 
   if (!SP->isDefinition()) {
     addFlag(SPDie, dwarf::DW_AT_declaration);
 
     // Add arguments. Do not add arguments for subprogram definition. They will
     // be handled while processing variables.
     constructSubprogramArguments(SPDie, Args);

 /// Returns true if the vector's size differs from the sum of sizes of elements
 /// the user specified.  This can occur if the vector has been rounded up to
 /// fit memory alignment constraints.
 static bool hasVectorBeenPadded(const DICompositeType *CTy) {
   assert(CTy && CTy->isVector() && "Composite type is not a vector");
   const uint64_t ActualSize = CTy->getSizeInBits();
 
   // Obtain the size of each element in the vector.
-  DIType *BaseTy = CTy->getBaseType().resolve();
+  DIType *BaseTy = CTy->getBaseType();
   assert(BaseTy && "Unknown vector element type.");
   const uint64_t ElementSize = BaseTy->getSizeInBits();
 
   // Locate the number of elements in the vector.
   const DINodeArray Elements = CTy->getElements();
   assert(Elements.size() == 1 &&
          Elements[0]->getTag() == dwarf::DW_TAG_subrange_type &&
          "Invalid vector element array, expected one element of type subrange");
void DwarfUnit::constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
   if (CTy->isVector()) {
     addFlag(Buffer, dwarf::DW_AT_GNU_vector);
     if (hasVectorBeenPadded(CTy))
       addUInt(Buffer, dwarf::DW_AT_byte_size, None,
               CTy->getSizeInBits() / CHAR_BIT);
   }
 
   // Emit the element type.
-  addType(Buffer, resolve(CTy->getBaseType()));
+  addType(Buffer, CTy->getBaseType());
 
   // Get an anonymous type for index type.
   // FIXME: This type should be passed down from the front end
   // as different languages may have different sizes for indexes.
   DIE *IdxTy = getIndexTyDie();
 
   // Add subranges to array type.
   DINodeArray Elements = CTy->getElements();
   for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
     // FIXME: Should this really be such a loose cast?
     if (auto *Element = dyn_cast_or_null<DINode>(Elements[i]))
       if (Element->getTag() == dwarf::DW_TAG_subrange_type)
         constructSubrangeDIE(Buffer, cast<DISubrange>(Element), IdxTy);
   }
 }
 
 void DwarfUnit::constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
-  const DIType *DTy = resolve(CTy->getBaseType());
+  const DIType *DTy = CTy->getBaseType();
   bool IsUnsigned = DTy && isUnsignedDIType(DD, DTy);
   if (DTy) {
     if (DD->getDwarfVersion() >= 3)
       addType(Buffer, DTy);
     if (DD->getDwarfVersion() >= 4 && (CTy->getFlags() & DINode::FlagEnumClass))
       addFlag(Buffer, dwarf::DW_AT_enum_class);
   }
 

 }
 
 DIE &DwarfUnit::constructMemberDIE(DIE &Buffer, const DIDerivedType *DT) {
   DIE &MemberDie = createAndAddDIE(DT->getTag(), Buffer);
   StringRef Name = DT->getName();
   if (!Name.empty())
     addString(MemberDie, dwarf::DW_AT_name, Name);
 
-  if (DIType *Resolved = resolve(DT->getBaseType()))
+  if (DIType *Resolved = DT->getBaseType())
     addType(MemberDie, Resolved);
 
   addSourceLine(MemberDie, DT);
 
   if (DT->getTag() == dwarf::DW_TAG_inheritance && DT->isVirtual()) {
 
     // For C++, virtual base classes are not at fixed offset. Use following
     // expression to extract appropriate offset from vtable.

 }
 
 DIE *DwarfUnit::getOrCreateStaticMemberDIE(const DIDerivedType *DT) {
   if (!DT)
     return nullptr;
 
   // Construct the context before querying for the existence of the DIE in case
   // such construction creates the DIE.
-  DIE *ContextDIE = getOrCreateContextDIE(resolve(DT->getScope()));
+  DIE *ContextDIE = getOrCreateContextDIE(DT->getScope());
   assert(dwarf::isType(ContextDIE->getTag()) &&
          "Static member should belong to a type.");
 
   if (DIE *StaticMemberDIE = getDIE(DT))
     return StaticMemberDIE;
 
   DIE &StaticMemberDIE = createAndAddDIE(DT->getTag(), *ContextDIE, DT);
 
-  const DIType *Ty = resolve(DT->getBaseType());
+  const DIType *Ty = DT->getBaseType();
 
   addString(StaticMemberDIE, dwarf::DW_AT_name, DT->getName());
   addType(StaticMemberDIE, Ty);
   addSourceLine(StaticMemberDIE, DT);
   addFlag(StaticMemberDIE, dwarf::DW_AT_external);
   addFlag(StaticMemberDIE, dwarf::DW_AT_declaration);
 
   // FIXME: We could omit private if the parent is a class_type, and

lib/IR/DIBuilder.cpp

 
 static DIImportedEntity *
 createImportedModule(LLVMContext &C, dwarf::Tag Tag, DIScope *Context,
                      Metadata *NS, DIFile *File, unsigned Line, StringRef Name,
                      SmallVectorImpl<TrackingMDNodeRef> &AllImportedModules) {
   if (Line)
     assert(File && "Source location has line number but no file");
   unsigned EntitiesCount = C.pImpl->DIImportedEntitys.size();
-  auto *M =
-      DIImportedEntity::get(C, Tag, Context, DINodeRef(NS), File, Line, Name);
+  auto *M = DIImportedEntity::get(C, Tag, Context, cast_or_null<DINode>(NS),
+                                  File, Line, Name);
   if (EntitiesCount < C.pImpl->DIImportedEntitys.size())
     // A new Imported Entity was just added to the context.
     // Add it to the Imported Modules list.
     AllImportedModules.emplace_back(M);
   return M;
 }
 
 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,

lib/IR/DebugInfo.cpp

 void DebugInfoFinder::processCompileUnit(DICompileUnit *CU) {
   if (!addCompileUnit(CU))
     return;
   for (auto DIG : CU->getGlobalVariables()) {
     if (!addGlobalVariable(DIG))
       continue;
     auto *GV = DIG->getVariable();
     processScope(GV->getScope());
-    processType(GV->getType().resolve());
+    processType(GV->getType());
   }
   for (auto *ET : CU->getEnumTypes())
     processType(ET);
   for (auto *RT : CU->getRetainedTypes())
     if (auto *T = dyn_cast<DIType>(RT))
       processType(T);
     else
       processSubprogram(cast<DISubprogram>(RT));
   for (auto *Import : CU->getImportedEntities()) {
-    auto *Entity = Import->getEntity().resolve();
+    auto *Entity = Import->getEntity();
     if (auto *T = dyn_cast<DIType>(Entity))
       processType(T);
     else if (auto *SP = dyn_cast<DISubprogram>(Entity))
       processSubprogram(SP);
     else if (auto *NS = dyn_cast<DINamespace>(Entity))
       processScope(NS->getScope());
     else if (auto *M = dyn_cast<DIModule>(Entity))
       processScope(M->getScope());
if (!Loc)
     return;
   processScope(Loc->getScope());
   processLocation(M, Loc->getInlinedAt());
 }
 
 void DebugInfoFinder::processType(DIType *DT) {
   if (!addType(DT))
     return;
-  processScope(DT->getScope().resolve());
+  processScope(DT->getScope());
   if (auto *ST = dyn_cast<DISubroutineType>(DT)) {
-    for (DITypeRef Ref : ST->getTypeArray())
-      processType(Ref.resolve());
+    for (DIType *Ref : ST->getTypeArray())
+      processType(Ref);
     return;
   }
   if (auto *DCT = dyn_cast<DICompositeType>(DT)) {
-    processType(DCT->getBaseType().resolve());
+    processType(DCT->getBaseType());
     for (Metadata *D : DCT->getElements()) {
       if (auto *T = dyn_cast<DIType>(D))
         processType(T);
       else if (auto *SP = dyn_cast<DISubprogram>(D))
         processSubprogram(SP);
     }
     return;
   }
   if (auto *DDT = dyn_cast<DIDerivedType>(DT)) {
-    processType(DDT->getBaseType().resolve());
+    processType(DDT->getBaseType());
   }
 }
 
 void DebugInfoFinder::processScope(DIScope *Scope) {
   if (!Scope)
     return;
   if (auto *Ty = dyn_cast<DIType>(Scope)) {
     processType(Ty);
void DebugInfoFinder::processScope(DIScope *Scope) {
   } else if (auto *M = dyn_cast<DIModule>(Scope)) {
     processScope(M->getScope());
   }
 }
 
 void DebugInfoFinder::processSubprogram(DISubprogram *SP) {
   if (!addSubprogram(SP))
     return;
-  processScope(SP->getScope().resolve());
+  processScope(SP->getScope());
   // Some of the users, e.g. CloneFunctionInto / CloneModule, need to set up a
   // ValueMap containing identity mappings for all of the DICompileUnit's, not
   // just DISubprogram's, referenced from anywhere within the Function being
   // cloned prior to calling MapMetadata / RemapInstruction to avoid their
   // duplication later as DICompileUnit's are also directly referenced by
   // llvm.dbg.cu list. Thefore we need to collect DICompileUnit's here as well.
   // Also, DICompileUnit's may reference DISubprogram's too and therefore need
   // to be at least looked through.
   processCompileUnit(SP->getUnit());
   processType(SP->getType());
   for (auto *Element : SP->getTemplateParams()) {
     if (auto *TType = dyn_cast<DITemplateTypeParameter>(Element)) {
-      processType(TType->getType().resolve());
+      processType(TType->getType());
     } else if (auto *TVal = dyn_cast<DITemplateValueParameter>(Element)) {
-      processType(TVal->getType().resolve());
+      processType(TVal->getType());
     }
   }
 }
 
 void DebugInfoFinder::processDeclare(const Module &M,
                                      const DbgDeclareInst *DDI) {
   auto *N = dyn_cast<MDNode>(DDI->getVariable());
   if (!N)
     return;
 
   auto *DV = dyn_cast<DILocalVariable>(N);
   if (!DV)
     return;
 
   if (!NodesSeen.insert(DV).second)
     return;
   processScope(DV->getScope());
-  processType(DV->getType().resolve());
+  processType(DV->getType());
 }
 
 void DebugInfoFinder::processValue(const Module &M, const DbgValueInst *DVI) {
   auto *N = dyn_cast<MDNode>(DVI->getVariable());
   if (!N)
     return;
 
   auto *DV = dyn_cast<DILocalVariable>(N);
   if (!DV)
     return;
 
   if (!NodesSeen.insert(DV).second)
     return;
   processScope(DV->getScope());
-  processType(DV->getType().resolve());
+  processType(DV->getType());
 }
 
 bool DebugInfoFinder::addType(DIType *DT) {
   if (!DT)
     return false;
 
   if (!NodesSeen.insert(DT).second)
     return false;

 
 private:
   // Create a new DISubprogram, to replace the one given.
   DISubprogram *getReplacementSubprogram(DISubprogram *MDS) {
     auto *FileAndScope = cast_or_null<DIFile>(map(MDS->getFile()));
     StringRef LinkageName = MDS->getName().empty() ? MDS->getLinkageName() : "";
     DISubprogram *Declaration = nullptr;
     auto *Type = cast_or_null<DISubroutineType>(map(MDS->getType()));
-    DITypeRef ContainingType(map(MDS->getContainingType()));
+    DIType *ContainingType =
+        cast_or_null<DIType>(map(MDS->getContainingType()));
     auto *Unit = cast_or_null<DICompileUnit>(map(MDS->getUnit()));
     auto Variables = nullptr;
     auto TemplateParams = nullptr;
 
     // Make a distinct DISubprogram, for situations that warrent it.
     auto distinctMDSubprogram = [&]() {
       return DISubprogram::getDistinct(
           MDS->getContext(), FileAndScope, MDS->getName(), LinkageName,

lib/IR/DebugInfoMetadata.cpp

const DILocation *DILocation::getMergedLocation(const DILocation *LocA,
   SmallPtrSet<DILocation *, 5> InlinedLocationsA;
   for (DILocation *L = LocA->getInlinedAt(); L; L = L->getInlinedAt())
     InlinedLocationsA.insert(L);
   SmallSet<std::pair<DIScope *, DILocation *>, 5> Locations;
   DIScope *S = LocA->getScope();
   DILocation *L = LocA->getInlinedAt();
   while (S) {
     Locations.insert(std::make_pair(S, L));
-    S = S->getScope().resolve();
+    S = S->getScope();
     if (!S && L) {
       S = L->getScope();
       L = L->getInlinedAt();
     }
   }
   const DILocation *Result = LocB;
   S = LocB->getScope();
   L = LocB->getInlinedAt();
   while (S) {
     if (Locations.count(std::make_pair(S, L)))
       break;
-    S = S->getScope().resolve();
+    S = S->getScope();
     if (!S && L) {
       S = L->getScope();
       L = L->getInlinedAt();
     }
   }
 
   // If the two locations are irreconsilable, just pick one. This is misleading,
   // but on the other hand, it's a "line 0" location.
#define HANDLE_DI_FLAG(ID, NAME)                                               \
   if (DIFlags Bit = Flags & Flag##NAME) {                                      \
     SplitFlags.push_back(Bit);                                                 \
     Flags &= ~Bit;                                                             \
   }
 #include "llvm/IR/DebugInfoFlags.def"
   return Flags;
 }
 
-DIScopeRef DIScope::getScope() const {
+DIScope *DIScope::getScope() const {
   if (auto *T = dyn_cast<DIType>(this))
     return T->getScope();
 
   if (auto *SP = dyn_cast<DISubprogram>(this))
     return SP->getScope();
 
   if (auto *LB = dyn_cast<DILexicalBlockBase>(this))
     return LB->getScope();

lib/Target/BPF/BTFDebug.cpp

BTFTypeDerived::BTFTypeDerived(const DIDerivedType *DTy, unsigned Tag)
   }
   BTFType.Info = Kind << 24;
 }
 
 void BTFTypeDerived::completeType(BTFDebug &BDebug) {
   BTFType.NameOff = BDebug.addString(DTy->getName());
 
   // The base type for PTR/CONST/VOLATILE could be void.
-  const DIType *ResolvedType = DTy->getBaseType().resolve();
+  const DIType *ResolvedType = DTy->getBaseType();
   if (!ResolvedType) {
     assert((Kind == BTF::BTF_KIND_PTR || Kind == BTF::BTF_KIND_CONST ||
             Kind == BTF::BTF_KIND_VOLATILE) &&
            "Invalid null basetype");
     BTFType.Type = 0;
   } else {
     BTFType.Type = BDebug.getTypeId(ResolvedType);
   }
for (const auto *Element : Elements) {
 
     BTFMember.NameOff = BDebug.addString(DDTy->getName());
     if (HasBitField) {
       uint8_t BitFieldSize = DDTy->isBitField() ? DDTy->getSizeInBits() : 0;
       BTFMember.Offset = BitFieldSize << 24 | DDTy->getOffsetInBits();
     } else {
       BTFMember.Offset = DDTy->getOffsetInBits();
     }
-    BTFMember.Type = BDebug.getTypeId(DDTy->getBaseType().resolve());
+    BTFMember.Type = BDebug.getTypeId(DDTy->getBaseType());
     Members.push_back(BTFMember);
   }
 }
 
 void BTFTypeStruct::emitType(MCStreamer &OS) {
   BTFTypeBase::emitType(OS);
   for (const auto &Member : Members) {
     OS.EmitIntValue(Member.NameOff, 4);
BTFTypeFuncProto::BTFTypeFuncProto(
     const std::unordered_map<uint32_t, StringRef> &FuncArgNames)
     : STy(STy), FuncArgNames(FuncArgNames) {
   Kind = BTF::BTF_KIND_FUNC_PROTO;
   BTFType.Info = (Kind << 24) | VLen;
 }
 
 void BTFTypeFuncProto::completeType(BTFDebug &BDebug) {
   DITypeRefArray Elements = STy->getTypeArray();
-  auto RetType = Elements[0].resolve();
+  auto RetType = Elements[0];
   BTFType.Type = RetType ? BDebug.getTypeId(RetType) : 0;
   BTFType.NameOff = 0;
 
   // For null parameter which is typically the last one
   // to represent the vararg, encode the NameOff/Type to be 0.
   for (unsigned I = 1, N = Elements.size(); I < N; ++I) {
     struct BTF::BTFParam Param;
-    auto Element = Elements[I].resolve();
+    auto Element = Elements[I];
     if (Element) {
       Param.NameOff = BDebug.addString(FuncArgNames[I]);
       Param.Type = BDebug.getTypeId(Element);
     } else {
       Param.NameOff = 0;
       Param.Type = 0;
     }
     Parameters.push_back(Param);
void BTFDebug::visitSubroutineType(
   auto TypeEntry = llvm::make_unique<BTFTypeFuncProto>(STy, VLen, FuncArgNames);
   if (ForSubprog)
     TypeId = addType(std::move(TypeEntry)); // For subprogram
   else
     TypeId = addType(std::move(TypeEntry), STy); // For func ptr
 
   // Visit return type and func arg types.
   for (const auto Element : Elements) {
-    visitTypeEntry(Element.resolve());
+    visitTypeEntry(Element);
   }
 }
 
 /// Handle structure/union types.
 void BTFDebug::visitStructType(const DICompositeType *CTy, bool IsStruct,
                                uint32_t &TypeId) {
   const DINodeArray Elements = CTy->getElements();
   uint32_t VLen = Elements.size();
void BTFDebug::visitStructType(const DICompositeType *CTy, bool IsStruct,
   // Visit all struct members.
   for (const auto *Element : Elements)
     visitTypeEntry(cast<DIDerivedType>(Element));
 }
 
 void BTFDebug::visitArrayType(const DICompositeType *CTy, uint32_t &TypeId) {
   // Visit array element type.
   uint32_t ElemTypeId;
-  visitTypeEntry(CTy->getBaseType().resolve(), ElemTypeId);
+  visitTypeEntry(CTy->getBaseType(), ElemTypeId);
 
   if (!CTy->getSizeInBits()) {
     auto TypeEntry = llvm::make_unique<BTFTypeArray>(ElemTypeId, 0);
     ElemTypeId = addType(std::move(TypeEntry), CTy);
   } else {
     // Visit array dimensions.
     DINodeArray Elements = CTy->getElements();
     for (int I = Elements.size() - 1; I >= 0; --I) {
if (Tag == dwarf::DW_TAG_pointer_type || Tag == dwarf::DW_TAG_typedef ||
     TypeId = addType(std::move(TypeEntry), DTy);
   } else if (Tag != dwarf::DW_TAG_member) {
     return;
   }
 
   // Visit base type of pointer, typedef, const, volatile, restrict or
   // struct/union member.
   uint32_t TempTypeId = 0;
-  visitTypeEntry(DTy->getBaseType().resolve(), TempTypeId);
+  visitTypeEntry(DTy->getBaseType(), TempTypeId);
 }
 
 void BTFDebug::visitTypeEntry(const DIType *Ty, uint32_t &TypeId) {
   if (!Ty || DIToIdMap.find(Ty) != DIToIdMap.end()) {
     TypeId = DIToIdMap[Ty];
     return;
   }
 
void BTFDebug::beginFunctionImpl(const MachineFunction *MF) {
   // Use RetainedNodes so we can collect all argument names
   // even if the argument is not used.
   std::unordered_map<uint32_t, StringRef> FuncArgNames;
   for (const DINode *DN : SP->getRetainedNodes()) {
     if (const auto *DV = dyn_cast<DILocalVariable>(DN)) {
       // Collect function arguments for subprogram func type.
       uint32_t Arg = DV->getArg();
       if (Arg) {
-        visitTypeEntry(DV->getType().resolve());
+        visitTypeEntry(DV->getType());
         FuncArgNames[Arg] = DV->getName();
       }
     }
   }
 
   // Construct subprogram func proto type.
   uint32_t ProtoTypeId;
   visitSubroutineType(SP->getType(), true, FuncArgNames, ProtoTypeId);
for (const GlobalVariable &Global : M->globals()) {
     // Ignore external globals for now.
     if (!Global.hasInitializer() && Global.hasExternalLinkage())
       continue;
 
     SmallVector<DIGlobalVariableExpression *, 1> GVs;
     Global.getDebugInfo(GVs);
     uint32_t GVTypeId = 0;
     for (auto *GVE : GVs) {
-      visitTypeEntry(GVE->getVariable()->getType().resolve(), GVTypeId);
+      visitTypeEntry(GVE->getVariable()->getType(), GVTypeId);
       break;
     }
 
     // Only support the following globals:
     //  . static variables
     //  . non-static global variables with section attributes
     // Essentially means:
     //  . .bcc/.data/.rodata DataSec entities only contain static data

tools/opt/BreakpointPrinter.cpp

struct BreakpointPrinter : public ModulePass {
   void getContextName(const DIScope *Context, std::string &N) {
     if (auto *NS = dyn_cast<DINamespace>(Context)) {
       if (!NS->getName().empty()) {
         getContextName(NS->getScope(), N);
         N = N + NS->getName().str() + "::";
       }
     } else if (auto *TY = dyn_cast<DIType>(Context)) {
       if (!TY->getName().empty()) {
-        getContextName(TY->getScope().resolve(), N);
+        getContextName(TY->getScope(), N);
         N = N + TY->getName().str() + "::";
       }
     }
   }
 
   bool runOnModule(Module &M) override {
     StringSet<> Processed;
     if (NamedMDNode *NMD = M.getNamedMetadata("llvm.dbg.sp"))
       for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
         std::string Name;
         auto *SP = cast_or_null<DISubprogram>(NMD->getOperand(i));
         if (!SP)
           continue;
-        getContextName(SP->getScope().resolve(), Name);
+        getContextName(SP->getScope(), Name);
         Name = Name + SP->getName().str();
         if (!Name.empty() && Processed.insert(Name).second) {
           Out << Name << "\n";
         }
       }
     return false;
   }