X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=include%2Fllvm%2FIR%2FDebugInfo.h;h=53c5e9ad120c8bde791d5c07cf1e89100ea4f796;hp=d2f752c5548dce850417ba6e3132508d4a4cc913;hb=92b3bf95a1846e16bb85929544747b1c074b2fab;hpb=12b14d9a76b8faaf96cebdc3a66e80f29d04db84

diff --git a/include/llvm/IR/DebugInfo.h b/include/llvm/IR/DebugInfo.h
index d2f752c5548..53c5e9ad120 100644
--- a/include/llvm/IR/DebugInfo.h
+++ b/include/llvm/IR/DebugInfo.h
@@ -51,1253 +51,259 @@ class DISubprogram;
 class DILexicalBlock;
 class DILexicalBlockFile;
 class DIVariable;
-class DIType;
-class DIScope;
 class DIObjCProperty;
 
 /// \brief Maps from type identifier to the actual MDNode.
 typedef DenseMap<const MDString *, MDNode *> DITypeIdentifierMap;
 
-class DIHeaderFieldIterator
-    : public std::iterator<std::input_iterator_tag, StringRef, std::ptrdiff_t,
-                           const StringRef *, StringRef> {
-  StringRef Header;
-  StringRef Current;
+#define DECLARE_SIMPLIFY_DESCRIPTOR(DESC)                                      \
+  class DESC;                                                                  \
+  template <> struct simplify_type<const DESC>;                                \
+  template <> struct simplify_type<DESC>;
+DECLARE_SIMPLIFY_DESCRIPTOR(DISubrange)
+DECLARE_SIMPLIFY_DESCRIPTOR(DIEnumerator)
+DECLARE_SIMPLIFY_DESCRIPTOR(DIFile)
+DECLARE_SIMPLIFY_DESCRIPTOR(DICompileUnit)
+DECLARE_SIMPLIFY_DESCRIPTOR(DISubprogram)
+DECLARE_SIMPLIFY_DESCRIPTOR(DILexicalBlock)
+DECLARE_SIMPLIFY_DESCRIPTOR(DILexicalBlockFile)
+DECLARE_SIMPLIFY_DESCRIPTOR(DINameSpace)
+DECLARE_SIMPLIFY_DESCRIPTOR(DITemplateTypeParameter)
+DECLARE_SIMPLIFY_DESCRIPTOR(DITemplateValueParameter)
+DECLARE_SIMPLIFY_DESCRIPTOR(DIGlobalVariable)
+DECLARE_SIMPLIFY_DESCRIPTOR(DIVariable)
+DECLARE_SIMPLIFY_DESCRIPTOR(DIExpression)
+DECLARE_SIMPLIFY_DESCRIPTOR(DILocation)
+DECLARE_SIMPLIFY_DESCRIPTOR(DIObjCProperty)
+DECLARE_SIMPLIFY_DESCRIPTOR(DIImportedEntity)
+#undef DECLARE_SIMPLIFY_DESCRIPTOR
+
+typedef DebugNodeArray DIArray;
+typedef MDTypeRefArray DITypeArray;
+
+class DISubrange {
+  MDSubrange *N;
 
 public:
-  DIHeaderFieldIterator() {}
-  explicit DIHeaderFieldIterator(StringRef Header)
-      : Header(Header), Current(Header.slice(0, Header.find('\0'))) {}
-  StringRef operator*() const { return Current; }
-  const StringRef *operator->() const { return &Current; }
-  DIHeaderFieldIterator &operator++() {
-    increment();
-    return *this;
-  }
-  DIHeaderFieldIterator operator++(int) {
-    DIHeaderFieldIterator X(*this);
-    increment();
-    return X;
-  }
-  bool operator==(const DIHeaderFieldIterator &X) const {
-    return Current.data() == X.Current.data();
-  }
-  bool operator!=(const DIHeaderFieldIterator &X) const {
-    return !(*this == X);
-  }
-
-  StringRef getHeader() const { return Header; }
-  StringRef getCurrent() const { return Current; }
-  StringRef getPrefix() const {
-    if (Current.begin() == Header.begin())
-      return StringRef();
-    return Header.slice(0, Current.begin() - Header.begin() - 1);
-  }
-  StringRef getSuffix() const {
-    if (Current.end() == Header.end())
-      return StringRef();
-    return Header.slice(Current.end() - Header.begin() + 1, StringRef::npos);
-  }
-
-  /// \brief Get the current field as a number.
-  ///
-  /// Convert the current field into a number.  Return \c 0 on error.
-  template <class T> T getNumber() const {
-    T Int;
-    if (getCurrent().getAsInteger(0, Int))
-      return 0;
-    return Int;
-  }
+  DISubrange(const MDSubrange *N = nullptr) : N(const_cast<MDSubrange *>(N)) {}
 
-private:
-  void increment() {
-    assert(Current.data() != nullptr && "Cannot increment past the end");
-    StringRef Suffix = getSuffix();
-    Current = Suffix.slice(0, Suffix.find('\0'));
-  }
+  operator MDSubrange *() const { return N; }
+  MDSubrange *operator->() const { return N; }
+  MDSubrange &operator*() const { return *N; }
 };
 
-/// \brief A thin wraper around MDNode to access encoded debug info.
-///
-/// This should not be stored in a container, because the underlying MDNode may
-/// change in certain situations.
-class DIDescriptor {
-  // Befriends DIRef so DIRef can befriend the protected member
-  // function: getFieldAs<DIRef>.
-  template <typename T> friend class DIRef;
-
-public:
-  /// \brief Duplicated debug info flags.
-  ///
-  /// \see DebugNode::DIFlags.
-  enum {
-#define HANDLE_DI_FLAG(ID, NAME) Flag##NAME = DebugNode::Flag##NAME,
-#include "llvm/IR/DebugInfoFlags.def"
-    FlagAccessibility = DebugNode::FlagAccessibility
-  };
-
-  static unsigned getFlag(StringRef Flag);
-  static const char *getFlagString(unsigned Flag);
-
-  /// \brief Split up a flags bitfield.
-  ///
-  /// Split \c Flags into \c SplitFlags, a vector of its components.  Returns
-  /// any remaining (unrecognized) bits.
-  static unsigned splitFlags(unsigned Flags,
-                             SmallVectorImpl<unsigned> &SplitFlags);
-
-protected:
-  const MDNode *DbgNode;
-
-  StringRef getStringField(unsigned Elt) const;
-  unsigned getUnsignedField(unsigned Elt) const {
-    return (unsigned)getUInt64Field(Elt);
-  }
-  uint64_t getUInt64Field(unsigned Elt) const;
-  int64_t getInt64Field(unsigned Elt) const;
-  DIDescriptor getDescriptorField(unsigned Elt) const;
-
-  template <typename DescTy> DescTy getFieldAs(unsigned Elt) const {
-    return DescTy(getDescriptorField(Elt));
-  }
-
-  GlobalVariable *getGlobalVariableField(unsigned Elt) const;
-  Constant *getConstantField(unsigned Elt) const;
-  Function *getFunctionField(unsigned Elt) const;
+class DIEnumerator {
+  MDEnumerator *N;
 
 public:
-  explicit DIDescriptor(const MDNode *N = nullptr) : DbgNode(N) {}
-
-  bool Verify() const;
-
-  MDNode *get() const { return const_cast<MDNode *>(DbgNode); }
-  operator MDNode *() const { return get(); }
-  MDNode *operator->() const { return get(); }
-  MDNode &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  // An explicit operator bool so that we can do testing of DI values
-  // easily.
-  // FIXME: This operator bool isn't actually protecting anything at the
-  // moment due to the conversion operator above making DIDescriptor nodes
-  // implicitly convertable to bool.
-  explicit operator bool() const { return DbgNode != nullptr; }
-
-  bool operator==(DIDescriptor Other) const { return DbgNode == Other.DbgNode; }
-  bool operator!=(DIDescriptor Other) const { return !operator==(Other); }
-
-  StringRef getHeader() const { return getStringField(0); }
+  DIEnumerator(const MDEnumerator *N = nullptr)
+      : N(const_cast<MDEnumerator *>(N)) {}
 
-  size_t getNumHeaderFields() const {
-    return std::distance(DIHeaderFieldIterator(getHeader()),
-                         DIHeaderFieldIterator());
-  }
-
-  DIHeaderFieldIterator header_begin() const {
-    return DIHeaderFieldIterator(getHeader());
-  }
-  DIHeaderFieldIterator header_end() const { return DIHeaderFieldIterator(); }
-
-  DIHeaderFieldIterator getHeaderIterator(unsigned Index) const {
-    // Since callers expect an empty string for out-of-range accesses, we can't
-    // use std::advance() here.
-    for (auto I = header_begin(), E = header_end(); I != E; ++I, --Index)
-      if (!Index)
-        return I;
-    return header_end();
-  }
-
-  StringRef getHeaderField(unsigned Index) const {
-    return *getHeaderIterator(Index);
-  }
-
-  template <class T> T getHeaderFieldAs(unsigned Index) const {
-    return getHeaderIterator(Index).getNumber<T>();
-  }
-
-  uint16_t getTag() const {
-    if (auto *N = dyn_cast_or_null<DebugNode>(get()))
-      return N->getTag();
-    return 0;
-  }
-
-  bool isDerivedType() const { return get() && isa<MDDerivedTypeBase>(get()); }
-  bool isCompositeType() const {
-    return get() && isa<MDCompositeTypeBase>(get());
-  }
-  bool isSubroutineType() const {
-    return get() && isa<MDSubroutineType>(get());
-  }
-  bool isBasicType() const { return get() && isa<MDBasicType>(get()); }
-  bool isVariable() const { return get() && isa<MDLocalVariable>(get()); }
-  bool isSubprogram() const { return get() && isa<MDSubprogram>(get()); }
-  bool isGlobalVariable() const {
-    return get() && isa<MDGlobalVariable>(get());
-  }
-  bool isScope() const { return get() && isa<MDScope>(get()); }
-  bool isFile() const { return get() && isa<MDFile>(get()); }
-  bool isCompileUnit() const { return get() && isa<MDCompileUnit>(get()); }
-  bool isNameSpace() const{ return get() && isa<MDNamespace>(get()); }
-  bool isLexicalBlockFile() const {
-    return get() && isa<MDLexicalBlockFile>(get());
-  }
-  bool isLexicalBlock() const {
-    return get() && isa<MDLexicalBlockBase>(get());
-  }
-  bool isSubrange() const { return get() && isa<MDSubrange>(get()); }
-  bool isEnumerator() const { return get() && isa<MDEnumerator>(get()); }
-  bool isType() const { return get() && isa<MDType>(get()); }
-  bool isTemplateTypeParameter() const {
-    return get() && isa<MDTemplateTypeParameter>(get());
-  }
-  bool isTemplateValueParameter() const {
-    return get() && isa<MDTemplateValueParameter>(get());
-  }
-  bool isObjCProperty() const { return get() && isa<MDObjCProperty>(get()); }
-  bool isImportedEntity() const {
-    return get() && isa<MDImportedEntity>(get());
-  }
-  bool isExpression() const { return get() && isa<MDExpression>(get()); }
-
-  void print(raw_ostream &OS) const;
-  void dump() const;
-
-  /// \brief Replace all uses of debug info referenced by this descriptor.
-  void replaceAllUsesWith(LLVMContext &VMContext, DIDescriptor D);
-  void replaceAllUsesWith(MDNode *D);
+  operator MDEnumerator *() const { return N; }
+  MDEnumerator *operator->() const { return N; }
+  MDEnumerator &operator*() const { return *N; }
 };
 
-/// \brief This is used to represent ranges, for array bounds.
-class DISubrange : public DIDescriptor {
-public:
-  explicit DISubrange(const MDNode *N = nullptr) : DIDescriptor(N) {}
-  DISubrange(const MDSubrange *N) : DIDescriptor(N) {}
+class DIFile {
+  MDFile *N;
 
-  MDSubrange *get() const {
-    return cast_or_null<MDSubrange>(DIDescriptor::get());
-  }
-  operator MDSubrange *() const { return get(); }
-  MDSubrange *operator->() const { return get(); }
-  MDSubrange &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  int64_t getLo() const { return get()->getLo(); }
-  int64_t getCount() const { return get()->getCount(); }
-  bool Verify() const;
-};
-
-/// \brief This descriptor holds an array of nodes with type T.
-template <typename T> class DITypedArray : public DIDescriptor {
 public:
-  explicit DITypedArray(const MDNode *N = nullptr) : DIDescriptor(N) {}
-  unsigned getNumElements() const {
-    return DbgNode ? DbgNode->getNumOperands() : 0;
-  }
-  T getElement(unsigned Idx) const { return getFieldAs<T>(Idx); }
-};
-
-typedef DITypedArray<DIDescriptor> DIArray;
+  DIFile(const MDFile *N = nullptr) : N(const_cast<MDFile *>(N)) {}
 
-/// \brief A wrapper for an enumerator (e.g. X and Y in 'enum {X,Y}').
-///
-/// FIXME: it seems strange that this doesn't have either a reference to the
-/// type/precision or a file/line pair for location info.
-class DIEnumerator : public DIDescriptor {
-public:
-  explicit DIEnumerator(const MDNode *N = nullptr) : DIDescriptor(N) {}
-  DIEnumerator(const MDEnumerator *N) : DIDescriptor(N) {}
-
-  MDEnumerator *get() const {
-    return cast_or_null<MDEnumerator>(DIDescriptor::get());
-  }
-  operator MDEnumerator *() const { return get(); }
-  MDEnumerator *operator->() const { return get(); }
-  MDEnumerator &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  StringRef getName() const { return get()->getName(); }
-  int64_t getEnumValue() const { return get()->getValue(); }
-  bool Verify() const;
+  operator MDFile *() const { return N; }
+  MDFile *operator->() const { return N; }
+  MDFile &operator*() const { return *N; }
 };
 
-template <typename T> class DIRef;
-typedef DIRef<DIDescriptor> DIDescriptorRef;
-typedef DIRef<DIScope> DIScopeRef;
-typedef DIRef<DIType> DITypeRef;
-typedef DITypedArray<DITypeRef> DITypeArray;
+class DICompileUnit {
+  MDCompileUnit *N;
 
-/// \brief A base class for various scopes.
-///
-/// Although, implementation-wise, DIScope is the parent class of most
-/// other DIxxx classes, including DIType and its descendants, most of
-/// DIScope's descendants are not a substitutable subtype of
-/// DIScope. The DIDescriptor::isScope() method only is true for
-/// DIScopes that are scopes in the strict lexical scope sense
-/// (DICompileUnit, DISubprogram, etc.), but not for, e.g., a DIType.
-class DIScope : public DIDescriptor {
 public:
-  explicit DIScope(const MDNode *N = nullptr) : DIDescriptor(N) {}
-  DIScope(const MDScope *N) : DIDescriptor(N) {}
-
-  MDScope *get() const { return cast_or_null<MDScope>(DIDescriptor::get()); }
-  operator MDScope *() const { return get(); }
-  MDScope *operator->() const { return get(); }
-  MDScope &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
+  DICompileUnit(const MDCompileUnit *N = nullptr)
+      : N(const_cast<MDCompileUnit *>(N)) {}
 
-  /// \brief Get the parent scope.
-  ///
-  /// Gets the parent scope for this scope node or returns a default
-  /// constructed scope.
-  DIScopeRef getContext() const;
-  /// \brief Get the scope name.
-  ///
-  /// If the scope node has a name, return that, else return an empty string.
-  StringRef getName() const;
-  StringRef getFilename() const;
-  StringRef getDirectory() const;
-
-  /// \brief Generate a reference to this DIScope.
-  ///
-  /// Uses the type identifier instead of the actual MDNode if possible, to
-  /// help type uniquing.
-  DIScopeRef getRef() const;
+  operator MDCompileUnit *() const { return N; }
+  MDCompileUnit *operator->() const { return N; }
+  MDCompileUnit &operator*() const { return *N; }
 };
 
-/// \brief Represents reference to a DIDescriptor.
-///
-/// Abstracts over direct and identifier-based metadata references.
-template <typename T> class DIRef {
-  template <typename DescTy>
-  friend DescTy DIDescriptor::getFieldAs(unsigned Elt) const;
-  friend DIScopeRef DIScope::getContext() const;
-  friend DIScopeRef DIScope::getRef() const;
-  friend class DIType;
-
-  /// \brief Val can be either a MDNode or a MDString.
-  ///
-  /// In the latter, MDString specifies the type identifier.
-  const Metadata *Val;
-  explicit DIRef(const Metadata *V);
-
-public:
-  T resolve(const DITypeIdentifierMap &Map) const;
-  StringRef getName() const;
-  operator Metadata *() const { return const_cast<Metadata *>(Val); }
-
-  static DIRef get(const Metadata *MD) { return DIRef(MD); }
-};
+class DISubprogram {
+  MDSubprogram *N;
 
-template <typename T>
-T DIRef<T>::resolve(const DITypeIdentifierMap &Map) const {
-  if (!Val)
-    return T();
-
-  if (const MDNode *MD = dyn_cast<MDNode>(Val))
-    return T(MD);
-
-  const MDString *MS = cast<MDString>(Val);
-  // Find the corresponding MDNode.
-  DITypeIdentifierMap::const_iterator Iter = Map.find(MS);
-  assert(Iter != Map.end() && "Identifier not in the type map?");
-  assert(DIDescriptor(Iter->second).isType() &&
-         "MDNode in DITypeIdentifierMap should be a DIType.");
-  return T(Iter->second);
-}
-
-template <typename T> StringRef DIRef<T>::getName() const {
-  if (!Val)
-    return StringRef();
-
-  if (const MDNode *MD = dyn_cast<MDNode>(Val))
-    return T(MD).getName();
-
-  const MDString *MS = cast<MDString>(Val);
-  return MS->getString();
-}
-
-/// \brief Handle fields that are references to DIDescriptors.
-template <>
-DIDescriptorRef DIDescriptor::getFieldAs<DIDescriptorRef>(unsigned Elt) const;
-/// \brief Specialize DIRef constructor for DIDescriptorRef.
-template <> DIRef<DIDescriptor>::DIRef(const Metadata *V);
-
-/// \brief Handle fields that are references to DIScopes.
-template <> DIScopeRef DIDescriptor::getFieldAs<DIScopeRef>(unsigned Elt) const;
-/// \brief Specialize DIRef constructor for DIScopeRef.
-template <> DIRef<DIScope>::DIRef(const Metadata *V);
-
-/// \brief Handle fields that are references to DITypes.
-template <> DITypeRef DIDescriptor::getFieldAs<DITypeRef>(unsigned Elt) const;
-/// \brief Specialize DIRef constructor for DITypeRef.
-template <> DIRef<DIType>::DIRef(const Metadata *V);
-
-/// \brief This is a wrapper for a type.
-///
-/// FIXME: Types should be factored much better so that CV qualifiers and
-/// others do not require a huge and empty descriptor full of zeros.
-class DIType : public DIScope {
 public:
-  explicit DIType(const MDNode *N = nullptr) : DIScope(N) {}
-  DIType(const MDType *N) : DIScope(N) {}
-
-  MDType *get() const { return cast_or_null<MDType>(DIDescriptor::get()); }
-  operator MDType *() const { return get(); }
-  MDType *operator->() const { return get(); }
-  MDType &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  operator DITypeRef() const {
-    assert(isType() &&
-           "constructing DITypeRef from an MDNode that is not a type");
-    return DITypeRef(&*getRef());
-  }
+  DISubprogram(const MDSubprogram *N = nullptr)
+      : N(const_cast<MDSubprogram *>(N)) {}
 
-  bool Verify() const;
-
-  DIScopeRef getContext() const { return DIScopeRef::get(get()->getScope()); }
-  StringRef getName() const { return get()->getName(); }
-  unsigned getLineNumber() const { return get()->getLine(); }
-  uint64_t getSizeInBits() const { return get()->getSizeInBits(); }
-  uint64_t getAlignInBits() const { return get()->getAlignInBits(); }
-  // FIXME: Offset is only used for DW_TAG_member nodes.  Making every type
-  // carry this is just plain insane.
-  uint64_t getOffsetInBits() const { return get()->getOffsetInBits(); }
-  unsigned getFlags() const { return get()->getFlags(); }
-  bool isPrivate() const {
-    return (getFlags() & FlagAccessibility) == FlagPrivate;
-  }
-  bool isProtected() const {
-    return (getFlags() & FlagAccessibility) == FlagProtected;
-  }
-  bool isPublic() const {
-    return (getFlags() & FlagAccessibility) == FlagPublic;
-  }
-  bool isForwardDecl() const { return (getFlags() & FlagFwdDecl) != 0; }
-  bool isAppleBlockExtension() const {
-    return (getFlags() & FlagAppleBlock) != 0;
-  }
-  bool isBlockByrefStruct() const {
-    return (getFlags() & FlagBlockByrefStruct) != 0;
-  }
-  bool isVirtual() const { return (getFlags() & FlagVirtual) != 0; }
-  bool isArtificial() const { return (getFlags() & FlagArtificial) != 0; }
-  bool isObjectPointer() const { return (getFlags() & FlagObjectPointer) != 0; }
-  bool isObjcClassComplete() const {
-    return (getFlags() & FlagObjcClassComplete) != 0;
-  }
-  bool isVector() const { return (getFlags() & FlagVector) != 0; }
-  bool isStaticMember() const { return (getFlags() & FlagStaticMember) != 0; }
-  bool isLValueReference() const {
-    return (getFlags() & FlagLValueReference) != 0;
-  }
-  bool isRValueReference() const {
-    return (getFlags() & FlagRValueReference) != 0;
-  }
-  bool isValid() const { return DbgNode && isType(); }
+  operator MDSubprogram *() const { return N; }
+  MDSubprogram *operator->() const { return N; }
+  MDSubprogram &operator*() const { return *N; }
 };
 
-/// \brief A basic type, like 'int' or 'float'.
-class DIBasicType : public DIType {
-public:
-  explicit DIBasicType(const MDNode *N = nullptr) : DIType(N) {}
-  DIBasicType(const MDBasicType *N) : DIType(N) {}
-
-  MDBasicType *get() const {
-    return cast_or_null<MDBasicType>(DIDescriptor::get());
-  }
-  operator MDBasicType *() const { return get(); }
-  MDBasicType *operator->() const { return get(); }
-  MDBasicType &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
+class DILexicalBlock {
+  MDLexicalBlockBase *N;
 
-  unsigned getEncoding() const { return get()->getEncoding(); }
-
-  bool Verify() const;
-};
-
-/// \brief A simple derived type
-///
-/// Like a const qualified type, a typedef, a pointer or reference, et cetera.
-/// Or, a data member of a class/struct/union.
-class DIDerivedType : public DIType {
 public:
-  explicit DIDerivedType(const MDNode *N = nullptr) : DIType(N) {}
-  DIDerivedType(const MDDerivedTypeBase *N) : DIType(N) {}
+  DILexicalBlock(const MDLexicalBlockBase *N = nullptr)
+      : N(const_cast<MDLexicalBlockBase *>(N)) {}
 
-  MDDerivedTypeBase *get() const {
-    return cast_or_null<MDDerivedTypeBase>(DIDescriptor::get());
-  }
-  operator MDDerivedTypeBase *() const { return get(); }
-  MDDerivedTypeBase *operator->() const { return get(); }
-  MDDerivedTypeBase &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  DITypeRef getTypeDerivedFrom() const {
-    return DITypeRef::get(get()->getBaseType());
-  }
-
-  /// \brief Return property node, if this ivar is associated with one.
-  MDNode *getObjCProperty() const {
-    if (auto *N = dyn_cast<MDDerivedType>(get()))
-      return dyn_cast_or_null<MDNode>(N->getExtraData());
-    return nullptr;
-  }
-
-  DITypeRef getClassType() const {
-    assert(getTag() == dwarf::DW_TAG_ptr_to_member_type);
-    if (auto *N = dyn_cast<MDDerivedType>(get()))
-      return DITypeRef::get(N->getExtraData());
-    return DITypeRef::get(nullptr);
-  }
-
-  Constant *getConstant() const {
-    assert((getTag() == dwarf::DW_TAG_member) && isStaticMember());
-    if (auto *N = dyn_cast<MDDerivedType>(get()))
-      if (auto *C = dyn_cast_or_null<ConstantAsMetadata>(N->getExtraData()))
-        return C->getValue();
-
-    return nullptr;
-  }
-
-  bool Verify() const;
+  operator MDLexicalBlockBase *() const { return N; }
+  MDLexicalBlockBase *operator->() const { return N; }
+  MDLexicalBlockBase &operator*() const { return *N; }
 };
 
-/// \brief Types that refer to multiple other types.
-///
-/// This descriptor holds a type that can refer to multiple other types, like a
-/// function or struct.
-///
-/// DICompositeType is derived from DIDerivedType because some
-/// composite types (such as enums) can be derived from basic types
-// FIXME: Make this derive from DIType directly & just store the
-// base type in a single DIType field.
-class DICompositeType : public DIDerivedType {
-  friend class DIBuilder;
-
-  /// \brief Set the array of member DITypes.
-  void setArraysHelper(MDNode *Elements, MDNode *TParams);
+class DILexicalBlockFile {
+  MDLexicalBlockFile *N;
 
 public:
-  explicit DICompositeType(const MDNode *N = nullptr) : DIDerivedType(N) {}
-  DICompositeType(const MDCompositeTypeBase *N) : DIDerivedType(N) {}
-
-  MDCompositeTypeBase *get() const {
-    return cast_or_null<MDCompositeTypeBase>(DIDescriptor::get());
-  }
-  operator MDCompositeTypeBase *() const { return get(); }
-  MDCompositeTypeBase *operator->() const { return get(); }
-  MDCompositeTypeBase &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  DIArray getElements() const {
-    assert(!isSubroutineType() && "no elements for DISubroutineType");
-    return DIArray(get()->getElements());
-  }
+  DILexicalBlockFile(const MDLexicalBlockFile *N = nullptr)
+      : N(const_cast<MDLexicalBlockFile *>(N)) {}
 
-private:
-  template <typename T>
-  void setArrays(DITypedArray<T> Elements, DIArray TParams = DIArray()) {
-    assert(
-        (!TParams || DbgNode->getNumOperands() == 8) &&
-        "If you're setting the template parameters this should include a slot "
-        "for that!");
-    setArraysHelper(Elements, TParams);
-  }
-
-public:
-  unsigned getRunTimeLang() const { return get()->getRuntimeLang(); }
-  DITypeRef getContainingType() const {
-    return DITypeRef::get(get()->getVTableHolder());
-  }
-
-private:
-  /// \brief Set the containing type.
-  void setContainingType(DICompositeType ContainingType);
-
-public:
-  DIArray getTemplateParams() const {
-    return DIArray(get()->getTemplateParams());
-  }
-  MDString *getIdentifier() const { return get()->getRawIdentifier(); }
-
-  bool Verify() const;
+  operator MDLexicalBlockFile *() const { return N; }
+  MDLexicalBlockFile *operator->() const { return N; }
+  MDLexicalBlockFile &operator*() const { return *N; }
 };
 
-class DISubroutineType : public DICompositeType {
-public:
-  explicit DISubroutineType(const MDNode *N = nullptr) : DICompositeType(N) {}
-  DISubroutineType(const MDSubroutineType *N) : DICompositeType(N) {}
+class DINameSpace {
+  MDNamespace *N;
 
-  MDSubroutineType *get() const {
-    return cast_or_null<MDSubroutineType>(DIDescriptor::get());
-  }
-  operator MDSubroutineType *() const { return get(); }
-  MDSubroutineType *operator->() const { return get(); }
-  MDSubroutineType &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  DITypedArray<DITypeRef> getTypeArray() const {
-    return DITypedArray<DITypeRef>(get()->getTypeArray());
-  }
-};
-
-/// \brief This is a wrapper for a file.
-class DIFile : public DIScope {
 public:
-  explicit DIFile(const MDNode *N = nullptr) : DIScope(N) {}
-  DIFile(const MDFile *N) : DIScope(N) {}
-
-  MDFile *get() const { return cast_or_null<MDFile>(DIDescriptor::get()); }
-  operator MDFile *() const { return get(); }
-  MDFile *operator->() const { return get(); }
-  MDFile &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
+  DINameSpace(const MDNamespace *N = nullptr)
+      : N(const_cast<MDNamespace *>(N)) {}
 
-  /// \brief Retrieve the MDNode for the directory/file pair.
-  MDNode *getFileNode() const { return get(); }
-  bool Verify() const;
+  operator MDNamespace *() const { return N; }
+  MDNamespace *operator->() const { return N; }
+  MDNamespace &operator*() const { return *N; }
 };
 
-/// \brief A wrapper for a compile unit.
-class DICompileUnit : public DIScope {
-public:
-  explicit DICompileUnit(const MDNode *N = nullptr) : DIScope(N) {}
-  DICompileUnit(const MDCompileUnit *N) : DIScope(N) {}
-
-  MDCompileUnit *get() const {
-    return cast_or_null<MDCompileUnit>(DIDescriptor::get());
-  }
-  operator MDCompileUnit *() const { return get(); }
-  MDCompileUnit *operator->() const { return get(); }
-  MDCompileUnit &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  dwarf::SourceLanguage getLanguage() const {
-    return static_cast<dwarf::SourceLanguage>(get()->getSourceLanguage());
-  }
-  StringRef getProducer() const { return get()->getProducer(); }
-  bool isOptimized() const { return get()->isOptimized(); }
-  StringRef getFlags() const { return get()->getFlags(); }
-  unsigned getRunTimeVersion() const { return get()->getRuntimeVersion(); }
-
-  DIArray getEnumTypes() const { return DIArray(get()->getEnumTypes()); }
-  DIArray getRetainedTypes() const {
-    return DIArray(get()->getRetainedTypes());
-  }
-  DIArray getSubprograms() const { return DIArray(get()->getSubprograms()); }
-  DIArray getGlobalVariables() const {
-    return DIArray(get()->getGlobalVariables());
-  }
-  DIArray getImportedEntities() const {
-    return DIArray(get()->getImportedEntities());
-  }
-
-  void replaceSubprograms(DIArray Subprograms);
-  void replaceGlobalVariables(DIArray GlobalVariables);
-
-  StringRef getSplitDebugFilename() const {
-    return get()->getSplitDebugFilename();
-  }
-  unsigned getEmissionKind() const { return get()->getEmissionKind(); }
+class DITemplateTypeParameter {
+  MDTemplateTypeParameter *N;
 
-  bool Verify() const;
-};
-
-/// \brief This is a wrapper for a subprogram (e.g. a function).
-class DISubprogram : public DIScope {
 public:
-  explicit DISubprogram(const MDNode *N = nullptr) : DIScope(N) {}
-  DISubprogram(const MDSubprogram *N) : DIScope(N) {}
-
-  MDSubprogram *get() const {
-    return cast_or_null<MDSubprogram>(DIDescriptor::get());
-  }
-  operator MDSubprogram *() const { return get(); }
-  MDSubprogram *operator->() const { return get(); }
-  MDSubprogram &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  StringRef getName() const { return get()->getName(); }
-  StringRef getDisplayName() const { return get()->getDisplayName(); }
-  StringRef getLinkageName() const { return get()->getLinkageName(); }
-  unsigned getLineNumber() const { return get()->getLine(); }
-
-  /// \brief Check if this is local (like 'static' in C).
-  unsigned isLocalToUnit() const { return get()->isLocalToUnit(); }
-  unsigned isDefinition() const { return get()->isDefinition(); }
-
-  unsigned getVirtuality() const { return get()->getVirtuality(); }
-  unsigned getVirtualIndex() const { return get()->getVirtualIndex(); }
-
-  unsigned getFlags() const { return get()->getFlags(); }
-
-  unsigned isOptimized() const { return get()->isOptimized(); }
-
-  /// \brief Get the beginning of the scope of the function (not the name).
-  unsigned getScopeLineNumber() const { return get()->getScopeLine(); }
-
-  DIScopeRef getContext() const { return DIScopeRef::get(get()->getScope()); }
-  DISubroutineType getType() const {
-    return DISubroutineType(get()->getType());
-  }
-
-  DITypeRef getContainingType() const {
-    return DITypeRef::get(get()->getContainingType());
-  }
-
-  bool Verify() const;
+  DITemplateTypeParameter(const MDTemplateTypeParameter *N = nullptr)
+      : N(const_cast<MDTemplateTypeParameter *>(N)) {}
 
-  /// \brief Check if this provides debugging information for the function F.
-  bool describes(const Function *F);
-
-  Function *getFunction() const;
-
-  void replaceFunction(Function *F) {
-    if (auto *N = get())
-      N->replaceFunction(F);
-  }
-  DIArray getTemplateParams() const {
-    return DIArray(get()->getTemplateParams());
-  }
-  DISubprogram getFunctionDeclaration() const {
-    return DISubprogram(get()->getDeclaration());
-  }
-  MDNode *getVariablesNodes() const { return getVariables(); }
-  DIArray getVariables() const { return DIArray(get()->getVariables()); }
-
-  unsigned isArtificial() const { return (getFlags() & FlagArtificial) != 0; }
-  /// \brief Check for the "private" access specifier.
-  bool isPrivate() const {
-    return (getFlags() & FlagAccessibility) == FlagPrivate;
-  }
-  /// \brief Check for the "protected" access specifier.
-  bool isProtected() const {
-    return (getFlags() & FlagAccessibility) == FlagProtected;
-  }
-  /// \brief Check for the "public" access specifier.
-  bool isPublic() const {
-    return (getFlags() & FlagAccessibility) == FlagPublic;
-  }
-  /// \brief Check for "explicit".
-  bool isExplicit() const { return (getFlags() & FlagExplicit) != 0; }
-  /// \brief Check if this is prototyped.
-  bool isPrototyped() const { return (getFlags() & FlagPrototyped) != 0; }
-
-  /// \brief Check if this is reference-qualified.
-  ///
-  /// Return true if this subprogram is a C++11 reference-qualified non-static
-  /// member function (void foo() &).
-  unsigned isLValueReference() const {
-    return (getFlags() & FlagLValueReference) != 0;
-  }
-
-  /// \brief Check if this is rvalue-reference-qualified.
-  ///
-  /// Return true if this subprogram is a C++11 rvalue-reference-qualified
-  /// non-static member function (void foo() &&).
-  unsigned isRValueReference() const {
-    return (getFlags() & FlagRValueReference) != 0;
-  }
+  operator MDTemplateTypeParameter *() const { return N; }
+  MDTemplateTypeParameter *operator->() const { return N; }
+  MDTemplateTypeParameter &operator*() const { return *N; }
 };
 
-/// \brief This is a wrapper for a lexical block.
-class DILexicalBlock : public DIScope {
-public:
-  explicit DILexicalBlock(const MDNode *N = nullptr) : DIScope(N) {}
-  DILexicalBlock(const MDLexicalBlock *N) : DIScope(N) {}
-
-  MDLexicalBlockBase *get() const {
-    return cast_or_null<MDLexicalBlockBase>(DIDescriptor::get());
-  }
-  operator MDLexicalBlockBase *() const { return get(); }
-  MDLexicalBlockBase *operator->() const { return get(); }
-  MDLexicalBlockBase &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  DIScope getContext() const { return DIScope(get()->getScope()); }
-  unsigned getLineNumber() const {
-    if (auto *N = dyn_cast<MDLexicalBlock>(get()))
-      return N->getLine();
-    return 0;
-  }
-  unsigned getColumnNumber() const {
-    if (auto *N = dyn_cast<MDLexicalBlock>(get()))
-      return N->getColumn();
-    return 0;
-  }
-  bool Verify() const;
-};
+class DITemplateValueParameter {
+  MDTemplateValueParameter *N;
 
-/// \brief This is a wrapper for a lexical block with a filename change.
-class DILexicalBlockFile : public DIScope {
 public:
-  explicit DILexicalBlockFile(const MDNode *N = nullptr) : DIScope(N) {}
-  DILexicalBlockFile(const MDLexicalBlockFile *N) : DIScope(N) {}
+  DITemplateValueParameter(const MDTemplateValueParameter *N = nullptr)
+      : N(const_cast<MDTemplateValueParameter *>(N)) {}
 
-  MDLexicalBlockFile *get() const {
-    return cast_or_null<MDLexicalBlockFile>(DIDescriptor::get());
-  }
-  operator MDLexicalBlockFile *() const { return get(); }
-  MDLexicalBlockFile *operator->() const { return get(); }
-  MDLexicalBlockFile &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  DIScope getContext() const { return getScope(); }
-  unsigned getLineNumber() const { return getScope().getLineNumber(); }
-  unsigned getColumnNumber() const { return getScope().getColumnNumber(); }
-  DILexicalBlock getScope() const { return DILexicalBlock(get()->getScope()); }
-  unsigned getDiscriminator() const { return get()->getDiscriminator(); }
-  bool Verify() const;
+  operator MDTemplateValueParameter *() const { return N; }
+  MDTemplateValueParameter *operator->() const { return N; }
+  MDTemplateValueParameter &operator*() const { return *N; }
 };
 
-/// \brief A wrapper for a C++ style name space.
-class DINameSpace : public DIScope {
-public:
-  explicit DINameSpace(const MDNode *N = nullptr) : DIScope(N) {}
-  DINameSpace(const MDNamespace *N) : DIScope(N) {}
-
-  MDNamespace *get() const {
-    return cast_or_null<MDNamespace>(DIDescriptor::get());
-  }
-  operator MDNamespace *() const { return get(); }
-  MDNamespace *operator->() const { return get(); }
-  MDNamespace &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
+class DIGlobalVariable {
+  MDGlobalVariable *N;
 
-  StringRef getName() const { return get()->getName(); }
-  unsigned getLineNumber() const { return get()->getLine(); }
-  DIScope getContext() const { return DIScope(get()->getScope()); }
-  bool Verify() const;
-};
-
-/// \brief This is a wrapper for template type parameter.
-class DITemplateTypeParameter : public DIDescriptor {
 public:
-  explicit DITemplateTypeParameter(const MDNode *N = nullptr)
-      : DIDescriptor(N) {}
-  DITemplateTypeParameter(const MDTemplateTypeParameter *N) : DIDescriptor(N) {}
-
-  MDTemplateTypeParameter *get() const {
-    return cast_or_null<MDTemplateTypeParameter>(DIDescriptor::get());
-  }
-  operator MDTemplateTypeParameter *() const { return get(); }
-  MDTemplateTypeParameter *operator->() const { return get(); }
-  MDTemplateTypeParameter &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
+  DIGlobalVariable(const MDGlobalVariable *N = nullptr)
+      : N(const_cast<MDGlobalVariable *>(N)) {}
 
-  StringRef getName() const { return get()->getName(); }
-
-  DITypeRef getType() const { return DITypeRef::get(get()->getType()); }
-  bool Verify() const;
+  operator MDGlobalVariable *() const { return N; }
+  MDGlobalVariable *operator->() const { return N; }
+  MDGlobalVariable &operator*() const { return *N; }
 };
 
-/// \brief This is a wrapper for template value parameter.
-class DITemplateValueParameter : public DIDescriptor {
-public:
-  explicit DITemplateValueParameter(const MDNode *N = nullptr)
-      : DIDescriptor(N) {}
-  DITemplateValueParameter(const MDTemplateValueParameter *N)
-      : DIDescriptor(N) {}
+class DIVariable {
+  MDLocalVariable *N;
 
-  MDTemplateValueParameter *get() const {
-    return cast_or_null<MDTemplateValueParameter>(DIDescriptor::get());
-  }
-  operator MDTemplateValueParameter *() const { return get(); }
-  MDTemplateValueParameter *operator->() const { return get(); }
-  MDTemplateValueParameter &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
+public:
+  DIVariable(const MDLocalVariable *N = nullptr)
+      : N(const_cast<MDLocalVariable *>(N)) {}
 
-  StringRef getName() const { return get()->getName(); }
-  DITypeRef getType() const { return DITypeRef::get(get()->getType()); }
-  Metadata *getValue() const { return get()->getValue(); }
-  bool Verify() const;
+  operator MDLocalVariable *() const { return N; }
+  MDLocalVariable *operator->() const { return N; }
+  MDLocalVariable &operator*() const { return *N; }
 };
 
-/// \brief This is a wrapper for a global variable.
-class DIGlobalVariable : public DIDescriptor {
-  DIFile getFile() const { return DIFile(get()->getFile()); }
+class DIExpression {
+  MDExpression *N;
 
 public:
-  explicit DIGlobalVariable(const MDNode *N = nullptr) : DIDescriptor(N) {}
-  DIGlobalVariable(const MDGlobalVariable *N) : DIDescriptor(N) {}
-
-  MDGlobalVariable *get() const {
-    return cast_or_null<MDGlobalVariable>(DIDescriptor::get());
-  }
-  operator MDGlobalVariable *() const { return get(); }
-  MDGlobalVariable *operator->() const { return get(); }
-  MDGlobalVariable &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  StringRef getName() const { return get()->getName(); }
-  StringRef getDisplayName() const { return get()->getDisplayName(); }
-  StringRef getLinkageName() const { return get()->getLinkageName(); }
-  unsigned getLineNumber() const { return get()->getLine(); }
-  unsigned isLocalToUnit() const { return get()->isLocalToUnit(); }
-  unsigned isDefinition() const { return get()->isDefinition(); }
-
-  DIScope getContext() const { return DIScope(get()->getScope()); }
-  StringRef getFilename() const { return getFile().getFilename(); }
-  StringRef getDirectory() const { return getFile().getDirectory(); }
-  DITypeRef getType() const { return DITypeRef::get(get()->getType()); }
-
-  GlobalVariable *getGlobal() const;
-  Constant *getConstant() const {
-    if (auto *N = get())
-      if (auto *C = dyn_cast_or_null<ConstantAsMetadata>(N->getVariable()))
-        return C->getValue();
-    return nullptr;
-  }
-  DIDerivedType getStaticDataMemberDeclaration() const {
-    return DIDerivedType(get()->getStaticDataMemberDeclaration());
-  }
+  DIExpression(const MDExpression *N = nullptr)
+      : N(const_cast<MDExpression *>(N)) {}
 
-  bool Verify() const;
+  operator MDExpression *() const { return N; }
+  MDExpression *operator->() const { return N; }
+  MDExpression &operator*() const { return *N; }
 };
 
-/// \brief This is a wrapper for a variable (e.g. parameter, local, global etc).
-class DIVariable : public DIDescriptor {
-  unsigned getFlags() const { return get()->getFlags(); }
+class DILocation {
+  MDLocation *N;
 
 public:
-  explicit DIVariable(const MDNode *N = nullptr) : DIDescriptor(N) {}
-  DIVariable(const MDLocalVariable *N) : DIDescriptor(N) {}
-
-  MDLocalVariable *get() const {
-    return cast_or_null<MDLocalVariable>(DIDescriptor::get());
-  }
-  operator MDLocalVariable *() const { return get(); }
-  MDLocalVariable *operator->() const { return get(); }
-  MDLocalVariable &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  StringRef getName() const { return get()->getName(); }
-  unsigned getLineNumber() const { return get()->getLine(); }
-  unsigned getArgNumber() const { return get()->getArg(); }
-
-  DIScope getContext() const { return DIScope(get()->getScope()); }
-  DIFile getFile() const { return DIFile(get()->getFile()); }
-  DITypeRef getType() const { return DITypeRef::get(get()->getType()); }
-
-  /// \brief Return true if this variable is marked as "artificial".
-  bool isArtificial() const {
-    return (getFlags() & FlagArtificial) != 0;
-  }
-
-  bool isObjectPointer() const {
-    return (getFlags() & FlagObjectPointer) != 0;
-  }
-
-  /// \brief If this variable is inlined then return inline location.
-  MDNode *getInlinedAt() const { return DIDescriptor(get()->getInlinedAt()); }
-
-  bool Verify() const;
-
-  /// \brief Check if this is a "__block" variable (Apple Blocks).
-  bool isBlockByrefVariable(const DITypeIdentifierMap &Map) const {
-    return (getType().resolve(Map)).isBlockByrefStruct();
-  }
-
-  /// \brief Check if this is an inlined function argument.
-  bool isInlinedFnArgument(const Function *CurFn);
+  DILocation(const MDLocation *N = nullptr) : N(const_cast<MDLocation *>(N)) {}
 
-  /// \brief Return the size reported by the variable's type.
-  unsigned getSizeInBits(const DITypeIdentifierMap &Map);
-
-  void printExtendedName(raw_ostream &OS) const;
+  operator MDLocation *() const { return N; }
+  MDLocation *operator->() const { return N; }
+  MDLocation &operator*() const { return *N; }
 };
 
-/// \brief A complex location expression in postfix notation.
-///
-/// This is (almost) a DWARF expression that modifies the location of a
-/// variable or (or the location of a single piece of a variable).
-///
-/// FIXME: Instead of DW_OP_plus taking an argument, this should use DW_OP_const
-/// and have DW_OP_plus consume the topmost elements on the stack.
-class DIExpression : public DIDescriptor {
-public:
-  explicit DIExpression(const MDNode *N = nullptr) : DIDescriptor(N) {}
-  DIExpression(const MDExpression *N) : DIDescriptor(N) {}
-
-  MDExpression *get() const {
-    return cast_or_null<MDExpression>(DIDescriptor::get());
-  }
-  operator MDExpression *() const { return get(); }
-  MDExpression *operator->() const { return get(); }
-  MDExpression &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  // Don't call this.  Call isValid() directly.
-  bool Verify() const = delete;
-
-  /// \brief Return the number of elements in the complex expression.
-  unsigned getNumElements() const { return get()->getNumElements(); }
-
-  /// \brief return the Idx'th complex address element.
-  uint64_t getElement(unsigned I) const { return get()->getElement(I); }
-
-  /// \brief Return whether this is a piece of an aggregate variable.
-  bool isBitPiece() const;
-  /// \brief Return the offset of this piece in bits.
-  uint64_t getBitPieceOffset() const;
-  /// \brief Return the size of this piece in bits.
-  uint64_t getBitPieceSize() const;
-
-  class iterator;
-  /// \brief A lightweight wrapper around an element of a DIExpression.
-  class Operand {
-    friend class iterator;
-    MDExpression::element_iterator I;
-    Operand() {}
-    Operand(MDExpression::element_iterator I) : I(I) {}
-  public:
-    /// \brief Operands such as DW_OP_piece have explicit (non-stack) arguments.
-    /// Argument 0 is the operand itself.
-    uint64_t getArg(unsigned N) const {
-      MDExpression::element_iterator In = I;
-      std::advance(In, N);
-      return *In;
-    }
-    operator uint64_t () const { return *I; }
-    /// \brief Returns underlying MDExpression::element_iterator.
-    const MDExpression::element_iterator &getBase() const { return I; }
-    /// \brief Returns the next operand.
-    iterator getNext() const;
-  };
-
-  /// \brief An iterator for DIExpression elements.
-  class iterator : public std::iterator<std::input_iterator_tag, StringRef,
-                                        unsigned, const Operand*, Operand> {
-    friend class Operand;
-    MDExpression::element_iterator I;
-    Operand Tmp;
-
-  public:
-    iterator(MDExpression::element_iterator I) : I(I) {}
-    const Operand &operator*() { return Tmp = Operand(I); }
-    const Operand *operator->() { return &(Tmp = Operand(I)); }
-    iterator &operator++() {
-      increment();
-      return *this;
-    }
-    iterator operator++(int) {
-      iterator X(*this);
-      increment();
-      return X;
-    }
-    bool operator==(const iterator &X) const { return I == X.I; }
-    bool operator!=(const iterator &X) const { return !(*this == X); }
-
-  private:
-    void increment() {
-      switch (**this) {
-      case dwarf::DW_OP_bit_piece: std::advance(I, 3); break;
-      case dwarf::DW_OP_plus:      std::advance(I, 2); break;
-      case dwarf::DW_OP_deref:     std::advance(I, 1); break;
-      default:
-        llvm_unreachable("unsupported operand");
-      }
-    }
-  };
-
-  iterator begin() const { return get()->elements_begin(); }
-  iterator end() const { return get()->elements_end(); }
-};
+class DIObjCProperty {
+  MDObjCProperty *N;
 
-/// \brief This object holds location information.
-///
-/// This object is not associated with any DWARF tag.
-class DILocation : public DIDescriptor {
 public:
-  explicit DILocation(const MDNode *N) : DIDescriptor(N) {}
-  DILocation(const MDLocation *N) : DIDescriptor(N) {}
+  DIObjCProperty(const MDObjCProperty *N = nullptr)
+      : N(const_cast<MDObjCProperty *>(N)) {}
 
-  MDLocation *get() const {
-    return cast_or_null<MDLocation>(DIDescriptor::get());
-  }
-  operator MDLocation *() const { return get(); }
-  MDLocation *operator->() const { return get(); }
-  MDLocation &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  unsigned getLineNumber() const { return get()->getLine(); }
-  unsigned getColumnNumber() const { return get()->getColumn(); }
-  DIScope getScope() const { return DIScope(get()->getScope()); }
-  DILocation getOrigLocation() const {
-    return DILocation(get()->getInlinedAt());
-  }
-  StringRef getFilename() const { return getScope().getFilename(); }
-  StringRef getDirectory() const { return getScope().getDirectory(); }
-  bool Verify() const;
-  bool atSameLineAs(const DILocation &Other) const {
-    return (getLineNumber() == Other.getLineNumber() &&
-            getFilename() == Other.getFilename());
-  }
-  /// \brief Get the DWAF discriminator.
-  ///
-  /// DWARF discriminators are used to distinguish identical file locations for
-  /// instructions that are on different basic blocks. If two instructions are
-  /// inside the same lexical block and are in different basic blocks, we
-  /// create a new lexical block with identical location as the original but
-  /// with a different discriminator value
-  /// (lib/Transforms/Util/AddDiscriminators.cpp for details).
-  unsigned getDiscriminator() const {
-    // Since discriminators are associated with lexical blocks, make
-    // sure this location is a lexical block before retrieving its
-    // value.
-    return getScope().isLexicalBlockFile()
-               ? DILexicalBlockFile(
-                     cast<MDNode>(cast<MDLocation>(DbgNode)->getScope()))
-                     .getDiscriminator()
-               : 0;
-  }
-
-  /// \brief Generate a new discriminator value for this location.
-  unsigned computeNewDiscriminator(LLVMContext &Ctx);
-
-  /// \brief Return a copy of this location with a different scope.
-  DILocation copyWithNewScope(LLVMContext &Ctx, DILexicalBlockFile NewScope);
+  operator MDObjCProperty *() const { return N; }
+  MDObjCProperty *operator->() const { return N; }
+  MDObjCProperty &operator*() const { return *N; }
 };
 
-class DIObjCProperty : public DIDescriptor {
-public:
-  explicit DIObjCProperty(const MDNode *N) : DIDescriptor(N) {}
-  DIObjCProperty(const MDObjCProperty *N) : DIDescriptor(N) {}
-
-  MDObjCProperty *get() const {
-    return cast_or_null<MDObjCProperty>(DIDescriptor::get());
-  }
-  operator MDObjCProperty *() const { return get(); }
-  MDObjCProperty *operator->() const { return get(); }
-  MDObjCProperty &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
+class DIImportedEntity {
+  MDImportedEntity *N;
 
-  StringRef getObjCPropertyName() const { return get()->getName(); }
-  DIFile getFile() const { return DIFile(get()->getFile()); }
-  unsigned getLineNumber() const { return get()->getLine(); }
-
-  StringRef getObjCPropertyGetterName() const { return get()->getGetterName(); }
-  StringRef getObjCPropertySetterName() const { return get()->getSetterName(); }
-  unsigned getAttributes() const { return get()->getAttributes(); }
-  bool isReadOnlyObjCProperty() const {
-    return (getAttributes() & dwarf::DW_APPLE_PROPERTY_readonly) != 0;
-  }
-  bool isReadWriteObjCProperty() const {
-    return (getAttributes() & dwarf::DW_APPLE_PROPERTY_readwrite) != 0;
-  }
-  bool isAssignObjCProperty() const {
-    return (getAttributes() & dwarf::DW_APPLE_PROPERTY_assign) != 0;
-  }
-  bool isRetainObjCProperty() const {
-    return (getAttributes() & dwarf::DW_APPLE_PROPERTY_retain) != 0;
-  }
-  bool isCopyObjCProperty() const {
-    return (getAttributes() & dwarf::DW_APPLE_PROPERTY_copy) != 0;
-  }
-  bool isNonAtomicObjCProperty() const {
-    return (getAttributes() & dwarf::DW_APPLE_PROPERTY_nonatomic) != 0;
-  }
-
-  /// \brief Get the type.
-  ///
-  /// \note Objective-C doesn't have an ODR, so there is no benefit in storing
-  /// the type as a DITypeRef here.
-  DIType getType() const { return DIType(get()->getType()); }
-
-  bool Verify() const;
-};
-
-/// \brief An imported module (C++ using directive or similar).
-class DIImportedEntity : public DIDescriptor {
 public:
-  DIImportedEntity() = default;
-  explicit DIImportedEntity(const MDNode *N) : DIDescriptor(N) {}
-  DIImportedEntity(const MDImportedEntity *N) : DIDescriptor(N) {}
+  DIImportedEntity(const MDImportedEntity *N = nullptr)
+      : N(const_cast<MDImportedEntity *>(N)) {}
 
-  MDImportedEntity *get() const {
-    return cast_or_null<MDImportedEntity>(DIDescriptor::get());
-  }
-  operator MDImportedEntity *() const { return get(); }
-  MDImportedEntity *operator->() const { return get(); }
-  MDImportedEntity &operator*() const {
-    assert(get() && "Expected valid pointer");
-    return *get();
-  }
-
-  DIScope getContext() const { return DIScope(get()->getScope()); }
-  DIDescriptorRef getEntity() const {
-    return DIDescriptorRef::get(get()->getEntity());
-  }
-  unsigned getLineNumber() const { return get()->getLine(); }
-  StringRef getName() const { return get()->getName(); }
-  bool Verify() const;
+  operator MDImportedEntity *() const { return N; }
+  MDImportedEntity *operator->() const { return N; }
+  MDImportedEntity &operator*() const { return *N; }
 };
 
+#define SIMPLIFY_DESCRIPTOR(DESC)                                              \
+  template <> struct simplify_type<const DESC> {                               \
+    typedef Metadata *SimpleType;                                              \
+    static SimpleType getSimplifiedValue(const DESC &DI) { return DI; }        \
+  };                                                                           \
+  template <> struct simplify_type<DESC> : simplify_type<const DESC> {};
+SIMPLIFY_DESCRIPTOR(DISubrange)
+SIMPLIFY_DESCRIPTOR(DIEnumerator)
+SIMPLIFY_DESCRIPTOR(DIFile)
+SIMPLIFY_DESCRIPTOR(DICompileUnit)
+SIMPLIFY_DESCRIPTOR(DISubprogram)
+SIMPLIFY_DESCRIPTOR(DILexicalBlock)
+SIMPLIFY_DESCRIPTOR(DILexicalBlockFile)
+SIMPLIFY_DESCRIPTOR(DINameSpace)
+SIMPLIFY_DESCRIPTOR(DITemplateTypeParameter)
+SIMPLIFY_DESCRIPTOR(DITemplateValueParameter)
+SIMPLIFY_DESCRIPTOR(DIGlobalVariable)
+SIMPLIFY_DESCRIPTOR(DIVariable)
+SIMPLIFY_DESCRIPTOR(DIExpression)
+SIMPLIFY_DESCRIPTOR(DILocation)
+SIMPLIFY_DESCRIPTOR(DIObjCProperty)
+SIMPLIFY_DESCRIPTOR(DIImportedEntity)
+#undef SIMPLIFY_DESCRIPTOR
+
 /// \brief Find subprogram that is enclosing this scope.
-DISubprogram getDISubprogram(const MDNode *Scope);
+MDSubprogram *getDISubprogram(const MDNode *Scope);
 
 /// \brief Find debug info for a given function.
 /// \returns a valid DISubprogram, if found. Otherwise, it returns an empty
 /// DISubprogram.
-DISubprogram getDISubprogram(const Function *F);
+MDSubprogram *getDISubprogram(const Function *F);
 
 /// \brief Find underlying composite type.
-DICompositeType getDICompositeType(DIType T);
-
-/// \brief Create a new inlined variable based on current variable.
-///
-/// @param DV            Current Variable.
-/// @param InlinedScope  Location at current variable is inlined.
-DIVariable createInlinedVariable(MDNode *DV, MDNode *InlinedScope,
-                                 LLVMContext &VMContext);
-
-/// \brief Remove inlined scope from the variable.
-DIVariable cleanseInlinedVariable(MDNode *DV, LLVMContext &VMContext);
+MDCompositeTypeBase *getDICompositeType(MDType *T);
 
 /// \brief Generate map by visiting all retained types.
 DITypeIdentifierMap generateDITypeIdentifierMap(const NamedMDNode *CU_Nodes);
@@ -1333,7 +339,7 @@ public:
   /// \brief Process DbgValueInst.
   void processValue(const Module &M, const DbgValueInst *DVI);
   /// \brief Process DILocation.
-  void processLocation(const Module &M, DILocation Loc);
+  void processLocation(const Module &M, const MDLocation *Loc);
 
   /// \brief Clear all lists.
   void reset();
@@ -1341,22 +347,23 @@ public:
 private:
   void InitializeTypeMap(const Module &M);
 
-  void processType(DIType DT);
-  void processSubprogram(DISubprogram SP);
-  void processScope(DIScope Scope);
-  bool addCompileUnit(DICompileUnit CU);
-  bool addGlobalVariable(DIGlobalVariable DIG);
-  bool addSubprogram(DISubprogram SP);
-  bool addType(DIType DT);
-  bool addScope(DIScope Scope);
+  void processType(MDType *DT);
+  void processSubprogram(MDSubprogram *SP);
+  void processScope(MDScope *Scope);
+  bool addCompileUnit(MDCompileUnit *CU);
+  bool addGlobalVariable(MDGlobalVariable *DIG);
+  bool addSubprogram(MDSubprogram *SP);
+  bool addType(MDType *DT);
+  bool addScope(MDScope *Scope);
 
 public:
-  typedef SmallVectorImpl<DICompileUnit>::const_iterator compile_unit_iterator;
-  typedef SmallVectorImpl<DISubprogram>::const_iterator subprogram_iterator;
-  typedef SmallVectorImpl<DIGlobalVariable>::const_iterator
+  typedef SmallVectorImpl<MDCompileUnit *>::const_iterator
+      compile_unit_iterator;
+  typedef SmallVectorImpl<MDSubprogram *>::const_iterator subprogram_iterator;
+  typedef SmallVectorImpl<MDGlobalVariable *>::const_iterator
       global_variable_iterator;
-  typedef SmallVectorImpl<DIType>::const_iterator type_iterator;
-  typedef SmallVectorImpl<DIScope>::const_iterator scope_iterator;
+  typedef SmallVectorImpl<MDType *>::const_iterator type_iterator;
+  typedef SmallVectorImpl<MDScope *>::const_iterator scope_iterator;
 
   iterator_range<compile_unit_iterator> compile_units() const {
     return iterator_range<compile_unit_iterator>(CUs.begin(), CUs.end());
@@ -1385,19 +392,19 @@ public:
   unsigned scope_count() const { return Scopes.size(); }
 
 private:
-  SmallVector<DICompileUnit, 8> CUs;
-  SmallVector<DISubprogram, 8> SPs;
-  SmallVector<DIGlobalVariable, 8> GVs;
-  SmallVector<DIType, 8> TYs;
-  SmallVector<DIScope, 8> Scopes;
-  SmallPtrSet<MDNode *, 64> NodesSeen;
+  SmallVector<MDCompileUnit *, 8> CUs;
+  SmallVector<MDSubprogram *, 8> SPs;
+  SmallVector<MDGlobalVariable *, 8> GVs;
+  SmallVector<MDType *, 8> TYs;
+  SmallVector<MDScope *, 8> Scopes;
+  SmallPtrSet<const MDNode *, 64> NodesSeen;
   DITypeIdentifierMap TypeIdentifierMap;
 
   /// \brief Specify if TypeIdentifierMap is initialized.
   bool TypeMapInitialized;
 };
 
-DenseMap<const Function *, DISubprogram> makeSubprogramMap(const Module &M);
+DenseMap<const Function *, MDSubprogram *> makeSubprogramMap(const Module &M);
 
 } // end namespace llvm