Desugaring optimizations. Add single-step desugaring methods to all

concrete types.  Use unqualified desugaring for getAs<> and sundry.
Fix a few users to either not desugar or use qualified desugar, as seemed
appropriate.  Removed Type's qualified desugar method, as it was easy
to accidentally use instead of QualType's.




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83116 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 206 insertions, 79 deletions

diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index cef52175d1..89776b91fe 100644
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -483,7 +483,9 @@ public:
     return CVR;
   }
 
-  bool isConstant(ASTContext& Ctx) const;
+  bool isConstant(ASTContext& Ctx) const {
+    return QualType::isConstant(*this, Ctx);
+  }
 
   // Don't promise in the API that anything besides 'const' can be
   // easily added.
@@ -548,7 +550,9 @@ public:
   /// concrete.
   ///
   /// Qualifiers are left in place.
-  QualType getDesugaredType(bool ForDisplay = false) const;
+  QualType getDesugaredType() const {
+    return QualType::getDesugaredType(*this);
+  }
 
   /// operator==/!= - Indicate whether the specified types and qualifiers are
   /// identical.
@@ -594,6 +598,13 @@ public:
   /// getNoReturnAttr - Returns true if the type has the noreturn attribute,
   /// false otherwise.
   bool getNoReturnAttr() const;
+
+private:
+  // These methods are implemented in a separate translation unit;
+  // "static"-ize them to avoid creating temporary QualTypes in the
+  // caller.
+  static bool isConstant(QualType T, ASTContext& Ctx);
+  static QualType getDesugaredType(QualType T);
 };
 
 } // end clang.
@@ -842,13 +853,10 @@ public:
   /// pointer, this returns the respective pointee.
   QualType getPointeeType() const;
 
-  /// getDesugaredType - Return the specified type with any "sugar" removed from
-  /// the type.  This takes off typedefs, typeof's etc.  If the outer level of
-  /// the type is already concrete, it returns it unmodified.  This is similar
-  /// to getting the canonical type, but it doesn't remove *all* typedefs.  For
-  /// example, it returns "T*" as "T*", (not as "int*"), because the pointer is
-  /// concrete.
-  QualType getDesugaredType(bool ForDisplay = false) const;
+  /// getUnqualifiedDesugaredType() - Return the specified type with
+  /// any "sugar" removed from the type, removing any typedefs,
+  /// typeofs, etc., as well as any qualifiers.
+  const Type *getUnqualifiedDesugaredType() const;
 
   /// More type predicates useful for type checking/promotion
   bool isPromotableIntegerType() const; // C99 6.3.1.1p2
@@ -946,6 +954,9 @@ public:
   Kind getKind() const { return TypeKind; }
   const char *getName(const LangOptions &LO) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
@@ -968,6 +979,9 @@ public:
   bool isSigned() const { return Signed; }
   const char *getName() const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
@@ -991,6 +1005,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, getElementType());
   }
@@ -1018,6 +1035,9 @@ public:
 
   QualType getPointeeType() const { return PointeeType; }
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, getPointeeType());
   }
@@ -1048,6 +1068,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
       Profile(ID, getPointeeType());
   }
@@ -1099,6 +1122,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == LValueReference;
   }
@@ -1116,6 +1142,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == RValueReference;
   }
@@ -1145,6 +1174,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, getPointeeType(), getClass());
   }
@@ -1237,6 +1269,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, getElementType(), getSize(),
             getSizeModifier(), getIndexTypeCVRQualifiers());
@@ -1286,6 +1321,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == ConstantArrayWithExpr;
   }
@@ -1314,6 +1352,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == ConstantArrayWithoutExpr;
   }
@@ -1337,6 +1378,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == IncompleteArray;
   }
@@ -1400,6 +1444,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == VariableArray;
   }
@@ -1453,6 +1500,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == DependentSizedArray;
   }
@@ -1502,6 +1552,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == DependentSizedExtVector;
   }
@@ -1544,6 +1597,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, getElementType(), getNumElements(), getTypeClass());
   }
@@ -1619,6 +1675,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == ExtVector;
   }
@@ -1661,7 +1720,6 @@ public:
   QualType getResultType() const { return ResultType; }
   bool getNoReturnAttr() const { return NoReturn; }
 
-
   static bool classof(const Type *T) {
     return T->getTypeClass() == FunctionNoProto ||
            T->getTypeClass() == FunctionProto;
@@ -1683,6 +1741,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, getResultType(), getNoReturnAttr());
   }
@@ -1793,6 +1854,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const Type *T) {
     return T->getTypeClass() == FunctionProto;
   }
@@ -1828,6 +1892,9 @@ public:
   /// looking through the typedefs for B will give you "const volatile A".
   QualType LookThroughTypedefs() const;
 
+  bool isSugared() const { return true; }
+  QualType desugar() const;
+
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
@@ -1845,6 +1912,12 @@ protected:
 public:
   Expr *getUnderlyingExpr() const { return TOExpr; }
 
+  /// \brief Remove a single level of sugar.
+  QualType desugar() const;
+
+  /// \brief Returns whether this type directly provides sugar.
+  bool isSugared() const { return true; }
+
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
@@ -1862,6 +1935,9 @@ public:
   DependentTypeOfExprType(ASTContext &Context, Expr *E)
     : TypeOfExprType(E), Context(Context) { }
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, Context, getUnderlyingExpr());
   }
@@ -1881,6 +1957,12 @@ class TypeOfType : public Type {
 public:
   QualType getUnderlyingType() const { return TOType; }
 
+  /// \brief Remove a single level of sugar.
+  QualType desugar() const { return getUnderlyingType(); }
+
+  /// \brief Returns whether this type directly provides sugar.
+  bool isSugared() const { return true; }
+
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
@@ -1904,6 +1986,12 @@ public:
   Expr *getUnderlyingExpr() const { return E; }
   QualType getUnderlyingType() const { return UnderlyingType; }
 
+  /// \brief Remove a single level of sugar.
+  QualType desugar() const { return getUnderlyingType(); }
+
+  /// \brief Returns whether this type directly provides sugar.
+  bool isSugared() const { return !isDependentType(); }
+
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
@@ -1919,6 +2007,9 @@ class DependentDecltypeType : public DecltypeType, public llvm::FoldingSetNode {
 public:
   DependentDecltypeType(ASTContext &Context, Expr *E);
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, Context, getUnderlyingExpr());
   }
@@ -1983,6 +2074,9 @@ public:
   // the same address space, and return that.
   unsigned getAddressSpace() const { return 0; }
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const TagType *T);
   static bool classof(const Type *T) {
     return isa<TagType>(T) && classof(cast<TagType>(T));
@@ -2002,6 +2096,9 @@ public:
     return reinterpret_cast<EnumDecl*>(TagType::getDecl());
   }
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   static bool classof(const TagType *T);
   static bool classof(const Type *T) {
     return isa<TagType>(T) && classof(cast<TagType>(T));
@@ -2043,6 +2140,12 @@ public:
   TagKind getTagKind() const { return Tag; }
   QualType getUnderlyingType() const { return UnderlyingType; }
 
+  /// \brief Remove a single level of sugar.
+  QualType desugar() const { return getUnderlyingType(); }
+
+  /// \brief Returns whether this type directly provides sugar.
+  bool isSugared() const { return true; }
+
   static const char *getNameForTagKind(TagKind Kind) {
     switch (Kind) {
     default: assert(0 && "Unknown TagKind!");
@@ -2094,6 +2197,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, Depth, Index, ParameterPack, Name);
   }
@@ -2185,6 +2291,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return !isDependentType(); }
+  QualType desugar() const { return getCanonicalTypeInternal(); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, Template, getArgs(), NumArgs, Context);
   }
@@ -2227,6 +2336,12 @@ public:
   /// \brief Retrieve the type named by the qualified-id.
   QualType getNamedType() const { return NamedType; }
 
+  /// \brief Remove a single level of sugar.
+  QualType desugar() const { return getNamedType(); }
+
+  /// \brief Returns whether this type directly provides sugar.
+  bool isSugared() const { return true; }
+
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
@@ -2307,6 +2422,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     Profile(ID, NNS, Name);
   }
@@ -2357,6 +2475,9 @@ public:
   virtual void getAsStringInternal(std::string &InnerString,
                                    const PrintingPolicy &Policy) const;
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID);
   static void Profile(llvm::FoldingSetNodeID &ID,
                       const ObjCInterfaceDecl *Decl,
@@ -2432,6 +2553,9 @@ public:
   /// interface type, or 0 if there are none.
   unsigned getNumProtocols() const { return Protocols.size(); }
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID);
   static void Profile(llvm::FoldingSetNodeID &ID, QualType T,
                       ObjCProtocolDecl **protocols, unsigned NumProtocols);
@@ -2472,6 +2596,9 @@ public:
   /// \brief Return the number of qualifying protocols.
   unsigned getNumProtocols() const { return Protocols.size(); }
 
+  bool isSugared() const { return false; }
+  QualType desugar() const { return QualType(this, 0); }
+
   void Profile(llvm::FoldingSetNodeID &ID);
   static void Profile(llvm::FoldingSetNodeID &ID, QualType T,
                       ObjCProtocolDecl **protocols, unsigned NumProtocols);
@@ -2803,7 +2930,7 @@ template <typename T> const T *Type::getAs() const {
 
   // If this is a typedef for the type, strip the typedef off without
   // losing all typedef information.
-  return cast<T>(getDesugaredType());
+  return cast<T>(getUnqualifiedDesugaredType());
 }
 
 }  // end namespace clang
diff --git a/include/clang/Analysis/PathSensitive/MemRegion.h b/include/clang/Analysis/PathSensitive/MemRegion.h
index ae0580afa4..0e487691a8 100644
--- a/include/clang/Analysis/PathSensitive/MemRegion.h
+++ b/include/clang/Analysis/PathSensitive/MemRegion.h
@@ -218,11 +218,11 @@ public:
 
   QualType getDesugaredValueType(ASTContext& C) const {
     QualType T = getValueType(C);
-    return T.getTypePtr() ? T->getDesugaredType() : T;
+    return T.getTypePtr() ? T.getDesugaredType() : T;
   }
 
   QualType getDesugaredLocationType(ASTContext& C) const {
-    return getLocationType(C)->getDesugaredType();
+    return getLocationType(C).getDesugaredType();
   }
 
   bool isBoundable() const {
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 70b9fa5946..0293862bae 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -22,12 +22,12 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace clang;
 
-bool QualType::isConstant(ASTContext &Ctx) const {
-  if (isConstQualified())
+bool QualType::isConstant(QualType T, ASTContext &Ctx) {
+  if (T.isConstQualified())
     return true;
 
-  if (getTypePtr()->isArrayType())
-    return Ctx.getAsArrayType(*this)->getElementType().isConstant(Ctx);
+  if (const ArrayType *AT = Ctx.getAsArrayType(T))
+    return AT->getElementType().isConstant(Ctx);
 
   return false;
 }
@@ -106,7 +106,8 @@ const Type *Type::getArrayElementTypeNoTypeQual() const {
 
   // If this is a typedef for an array type, strip the typedef off without
   // losing all typedef information.
-  return cast<ArrayType>(getDesugaredType())->getElementType().getTypePtr();
+  return cast<ArrayType>(getUnqualifiedDesugaredType())
+    ->getElementType().getTypePtr();
 }
 
 /// getDesugaredType - Return the specified type with any "sugar" removed from
@@ -115,62 +116,46 @@ const Type *Type::getArrayElementTypeNoTypeQual() const {
 /// to getting the canonical type, but it doesn't remove *all* typedefs.  For
 /// example, it returns "T*" as "T*", (not as "int*"), because the pointer is
 /// concrete.
-///
-/// \param ForDisplay When true, the desugaring is provided for
-/// display purposes only. In this case, we apply more heuristics to
-/// decide whether it is worth providing a desugared form of the type
-/// or not.
-QualType QualType::getDesugaredType(bool ForDisplay) const {
+QualType QualType::getDesugaredType(QualType T) {
   QualifierCollector Qs;
-  return Qs.apply(Qs.strip(*this)->getDesugaredType(ForDisplay));
-}
 
-/// getDesugaredType - Return the specified type with any "sugar" removed from
-/// type type.  This takes off typedefs, typeof's etc.  If the outer level of
-/// the type is already concrete, it returns it unmodified.  This is similar
-/// to getting the canonical type, but it doesn't remove *all* typedefs.  For
-/// example, it return "T*" as "T*", (not as "int*"), because the pointer is
-/// concrete.
-///
-/// \param ForDisplay When true, the desugaring is provided for
-/// display purposes only. In this case, we apply more heuristics to
-/// decide whether it is worth providing a desugared form of the type
-/// or not.
-QualType Type::getDesugaredType(bool ForDisplay) const {
-  if (const TypedefType *TDT = dyn_cast<TypedefType>(this))
-    return TDT->LookThroughTypedefs().getDesugaredType();
-  if (const ElaboratedType *ET = dyn_cast<ElaboratedType>(this))
-    return ET->getUnderlyingType().getDesugaredType();
-  if (const TypeOfExprType *TOE = dyn_cast<TypeOfExprType>(this))
-    return TOE->getUnderlyingExpr()->getType().getDesugaredType();
-  if (const TypeOfType *TOT = dyn_cast<TypeOfType>(this))
-    return TOT->getUnderlyingType().getDesugaredType();
-  if (const DecltypeType *DTT = dyn_cast<DecltypeType>(this)) {
-    if (!DTT->getUnderlyingType()->isDependentType())
-      return DTT->getUnderlyingType().getDesugaredType();
-  }
-  if (const TemplateSpecializationType *Spec
-        = dyn_cast<TemplateSpecializationType>(this)) {
-    if (ForDisplay)
-      return QualType(this, 0);
-
-    QualType Canon = Spec->getCanonicalTypeInternal();
-    if (Canon->getAs<TemplateSpecializationType>())
-      return QualType(this, 0);
-    return Canon->getDesugaredType();
-  }
-  if (const QualifiedNameType *QualName  = dyn_cast<QualifiedNameType>(this)) {
-    if (ForDisplay) {
-      // If desugaring the type that the qualified name is referring to
-      // produces something interesting, that's our desugared type.
-      QualType NamedType = QualName->getNamedType().getDesugaredType();
-      if (NamedType != QualName->getNamedType())
-        return NamedType;
-    } else
-      return QualName->getNamedType().getDesugaredType();
+  QualType Cur = T;
+  while (true) {
+    const Type *CurTy = Qs.strip(Cur);
+    switch (CurTy->getTypeClass()) {
+#define ABSTRACT_TYPE(Class, Parent)
+#define TYPE(Class, Parent) \
+    case Type::Class: { \
+      const Class##Type *Ty = cast<Class##Type>(CurTy); \
+      if (!Ty->isSugared()) \
+        return Qs.apply(Cur); \
+      Cur = Ty->desugar(); \
+      break; \
+    }
+#include "clang/AST/TypeNodes.def"
+    }
   }
+}
 
-  return QualType(this, 0);
+/// getUnqualifiedDesugaredType - Pull any qualifiers and syntactic
+/// sugar off the given type.  This should produce an object of the
+/// same dynamic type as the canonical type.
+const Type *Type::getUnqualifiedDesugaredType() const {
+  const Type *Cur = this;
+
+  while (true) {
+    switch (Cur->getTypeClass()) {
+#define ABSTRACT_TYPE(Class, Parent)
+#define TYPE(Class, Parent) \
+    case Class: { \
+      const Class##Type *Ty = cast<Class##Type>(Cur); \
+      if (!Ty->isSugared()) return Cur; \
+      Cur = Ty->desugar().getTypePtr(); \
+      break; \
+    }
+#include "clang/AST/TypeNodes.def"
+    }
+  }
 }
 
 /// isVoidType - Helper method to determine if this is the 'void' type.
@@ -303,7 +288,7 @@ const RecordType *Type::getAsStructureType() const {
 
     // If this is a typedef for a structure type, strip the typedef off without
     // losing all typedef information.
-    return cast<RecordType>(getDesugaredType());
+    return cast<RecordType>(getUnqualifiedDesugaredType());
   }
   return 0;
 }
@@ -322,7 +307,7 @@ const RecordType *Type::getAsUnionType() const {
 
     // If this is a typedef for a union type, strip the typedef off without
     // losing all typedef information.
-    return cast<RecordType>(getDesugaredType());
+    return cast<RecordType>(getUnqualifiedDesugaredType());
   }
 
   return 0;
@@ -790,10 +775,18 @@ QualType TypedefType::LookThroughTypedefs() const {
   return Qs.apply(CurType);
 }
 
+QualType TypedefType::desugar() const {
+  return getDecl()->getUnderlyingType();
+}
+
 TypeOfExprType::TypeOfExprType(Expr *E, QualType can)
   : Type(TypeOfExpr, can, E->isTypeDependent()), TOExpr(E) {
 }
 
+QualType TypeOfExprType::desugar() const {
+  return getUnderlyingExpr()->getType();
+}
+
 void DependentTypeOfExprType::Profile(llvm::FoldingSetNodeID &ID,
                                       ASTContext &Context, Expr *E) {
   E->Profile(ID, Context, true);
diff --git a/lib/Analysis/RegionStore.cpp b/lib/Analysis/RegionStore.cpp
index f63e9d874e..7a433dd148 100644
--- a/lib/Analysis/RegionStore.cpp
+++ b/lib/Analysis/RegionStore.cpp
@@ -770,7 +770,7 @@ SVal RegionStoreManager::ArrayToPointer(Loc Array) {
     return UnknownVal();
 
   // Strip off typedefs from the ArrayRegion's ValueType.
-  QualType T = ArrayR->getValueType(getContext())->getDesugaredType();
+  QualType T = ArrayR->getValueType(getContext()).getDesugaredType();
   ArrayType *AT = cast<ArrayType>(T);
   T = AT->getElementType();
 
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index 81f7283e23..3aae2563d1 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -44,16 +44,23 @@ static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
 
     // If this is a sugared type (like a typedef, typeof, etc), then unwrap one
     // level of the sugar so that the type is more obvious to the user.
-    QualType DesugaredTy = Ty.getDesugaredType(true);
+    QualType DesugaredTy = Ty.getDesugaredType();
 
     if (Ty != DesugaredTy &&
         // If the desugared type is a vector type, we don't want to expand it,
         // it will turn into an attribute mess. People want their "vec4".
         !isa<VectorType>(DesugaredTy) &&
 
-        // Don't aka just because we saw an elaborated type.
+        // Don't aka just because we saw an elaborated type...
         (!isa<ElaboratedType>(Ty) ||
-         cast<ElaboratedType>(Ty)->getUnderlyingType() != DesugaredTy) &&
+         cast<ElaboratedType>(Ty)->desugar() != DesugaredTy) &&
+
+        // ...or a qualified name type...
+        (!isa<QualifiedNameType>(Ty) ||
+         cast<QualifiedNameType>(Ty)->desugar() != DesugaredTy) &&
+
+        // ...or a non-dependent template specialization.
+        (!isa<TemplateSpecializationType>(Ty) || Ty->isDependentType()) &&
 
         // Don't desugar magic Objective-C types.
         Ty.getUnqualifiedType() != Context.getObjCIdType() &&
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 7aa0261ff6..223662afce 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -1267,7 +1267,7 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
         assert(BaseClass && "ActOnMemInitializers - neither field or base");
         Diag(Member->getSourceLocation(),
              diag::error_multiple_base_initialization)
-          << BaseClass->getDesugaredType(true);
+          << QualType(BaseClass, 0);
       }
       Diag(PrevMember->getSourceLocation(), diag::note_previous_initializer)
         << 0;
@@ -1336,7 +1336,7 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
         Type *BaseClass = PrevMember->getBaseClass();
         Diag(PrevMember->getSourceLocation(),
              diag::warn_base_initialized)
-              << BaseClass->getDesugaredType(true);
+          << QualType(BaseClass, 0);
       } else {
         FieldDecl *Field = PrevMember->getMember();
         Diag(PrevMember->getSourceLocation(),
@@ -1352,7 +1352,7 @@ void Sema::ActOnMemInitializers(DeclPtrTy ConstructorDecl,
         Type *BaseClass = Member->getBaseClass();
         Diag(Member->getSourceLocation(),
              diag::note_fieldorbase_initialized_here) << 1
-          << BaseClass->getDesugaredType(true);
+          << QualType(BaseClass, 0);
       }
       for (curIndex = 0; curIndex < Last; curIndex++)
         if (MemberInCtorList == AllBaseOrMembers[curIndex])