diff --git a/include/clang/AST/ASTVector.h b/include/clang/AST/ASTVector.h
index 0d4b3c4..71a6878 100644
--- a/include/clang/AST/ASTVector.h
+++ b/include/clang/AST/ASTVector.h
@@ -63,7 +63,7 @@
   // Default ctor - Initialize to empty.
   ASTVector() : Begin(NULL), End(NULL), Capacity(NULL) { }
 
-  ASTVector(ASTContext &C, unsigned N)
+  ASTVector(const ASTContext &C, unsigned N)
   : Begin(NULL), End(NULL), Capacity(NULL) {
     reserve(C, N);
   }
@@ -155,7 +155,7 @@
     return const_pointer(Begin);
   }
 
-  void push_back(const_reference Elt, ASTContext &C) {
+  void push_back(const_reference Elt, const ASTContext &C) {
     if (End < Capacity) {
     Retry:
       new (End) T(Elt);
@@ -166,7 +166,7 @@
     goto Retry;
   }
 
-  void reserve(ASTContext &C, unsigned N) {
+  void reserve(const ASTContext &C, unsigned N) {
     if (unsigned(Capacity-Begin) < N)
       grow(C, N);
   }
@@ -178,7 +178,7 @@
   /// append - Add the specified range to the end of the SmallVector.
   ///
   template<typename in_iter>
-  void append(ASTContext &C, in_iter in_start, in_iter in_end) {
+  void append(const ASTContext &C, in_iter in_start, in_iter in_end) {
     size_type NumInputs = std::distance(in_start, in_end);
 
     if (NumInputs == 0)
@@ -197,7 +197,7 @@
 
   /// append - Add the specified range to the end of the SmallVector.
   ///
-  void append(ASTContext &C, size_type NumInputs, const T &Elt) {
+  void append(const ASTContext &C, size_type NumInputs, const T &Elt) {
     // Grow allocated space if needed.
     if (NumInputs > size_type(this->capacity_ptr()-this->end()))
       this->grow(C, this->size()+NumInputs);
@@ -214,7 +214,7 @@
     std::uninitialized_copy(I, E, Dest);
   }
 
-  iterator insert(ASTContext &C, iterator I, const T &Elt) {
+  iterator insert(const ASTContext &C, iterator I, const T &Elt) {
     if (I == this->end()) {  // Important special case for empty vector.
       push_back(Elt, C);
       return this->end()-1;
@@ -235,7 +235,7 @@
     goto Retry;
   }
 
-  iterator insert(ASTContext &C, iterator I, size_type NumToInsert,
+  iterator insert(const ASTContext &C, iterator I, size_type NumToInsert,
                   const T &Elt) {
     if (I == this->end()) {  // Important special case for empty vector.
       append(C, NumToInsert, Elt);
@@ -284,7 +284,7 @@
   }
 
   template<typename ItTy>
-  iterator insert(ASTContext &C, iterator I, ItTy From, ItTy To) {
+  iterator insert(const ASTContext &C, iterator I, ItTy From, ItTy To) {
     if (I == this->end()) {  // Important special case for empty vector.
       append(C, From, To);
       return this->end()-1;
@@ -335,7 +335,7 @@
     return I;
   }
 
-  void resize(ASTContext &C, unsigned N, const T &NV) {
+  void resize(const ASTContext &C, unsigned N, const T &NV) {
     if (N < this->size()) {
       this->destroy_range(this->begin()+N, this->end());
       this->setEnd(this->begin()+N);
@@ -350,7 +350,7 @@
 private:
   /// grow - double the size of the allocated memory, guaranteeing space for at
   /// least one more element or MinSize if specified.
-  void grow(ASTContext &C, size_type MinSize = 1);
+  void grow(const ASTContext &C, size_type MinSize = 1);
 
   void construct_range(T *S, T *E, const T &Elt) {
     for (; S != E; ++S)
@@ -370,7 +370,7 @@
 
 // Define this out-of-line to dissuade the C++ compiler from inlining it.
 template <typename T>
-void ASTVector<T>::grow(ASTContext &C, size_t MinSize) {
+void ASTVector<T>::grow(const ASTContext &C, size_t MinSize) {
   size_t CurCapacity = Capacity-Begin;
   size_t CurSize = size();
   size_t NewCapacity = 2*CurCapacity;
diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index f641578..1d957aa 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -1220,13 +1220,15 @@
     else
       return llvm::APInt(BitWidth, VAL);
   }
-  void setIntValue(ASTContext &C, const llvm::APInt &Val);
+  void setIntValue(const ASTContext &C, const llvm::APInt &Val);
 };
 
 class APIntStorage : private APNumericStorage {
 public:
   llvm::APInt getValue() const { return getIntValue(); }
-  void setValue(ASTContext &C, const llvm::APInt &Val) { setIntValue(C, Val); }
+  void setValue(const ASTContext &C, const llvm::APInt &Val) {
+    setIntValue(C, Val);
+  }
 };
 
 class APFloatStorage : private APNumericStorage {
@@ -1234,7 +1236,7 @@
   llvm::APFloat getValue(const llvm::fltSemantics &Semantics) const {
     return llvm::APFloat(Semantics, getIntValue());
   }
-  void setValue(ASTContext &C, const llvm::APFloat &Val) {
+  void setValue(const ASTContext &C, const llvm::APFloat &Val) {
     setIntValue(C, Val.bitcastToAPInt());
   }
 };
@@ -1249,17 +1251,17 @@
 public:
   // type should be IntTy, LongTy, LongLongTy, UnsignedIntTy, UnsignedLongTy,
   // or UnsignedLongLongTy
-  IntegerLiteral(ASTContext &C, const llvm::APInt &V, QualType type,
+  IntegerLiteral(const ASTContext &C, const llvm::APInt &V, QualType type,
                  SourceLocation l);
 
   /// \brief Returns a new integer literal with value 'V' and type 'type'.
   /// \param type - either IntTy, LongTy, LongLongTy, UnsignedIntTy,
   /// UnsignedLongTy, or UnsignedLongLongTy which should match the size of V
   /// \param V - the value that the returned integer literal contains.
-  static IntegerLiteral *Create(ASTContext &C, const llvm::APInt &V,
+  static IntegerLiteral *Create(const ASTContext &C, const llvm::APInt &V,
                                 QualType type, SourceLocation l);
   /// \brief Returns a new empty integer literal.
-  static IntegerLiteral *Create(ASTContext &C, EmptyShell Empty);
+  static IntegerLiteral *Create(const ASTContext &C, EmptyShell Empty);
 
   SourceLocation getLocStart() const LLVM_READONLY { return Loc; }
   SourceLocation getLocEnd() const LLVM_READONLY { return Loc; }
@@ -1327,21 +1329,21 @@
 class FloatingLiteral : public Expr, private APFloatStorage {
   SourceLocation Loc;
 
-  FloatingLiteral(ASTContext &C, const llvm::APFloat &V, bool isexact,
+  FloatingLiteral(const ASTContext &C, const llvm::APFloat &V, bool isexact,
                   QualType Type, SourceLocation L);
 
   /// \brief Construct an empty floating-point literal.
-  explicit FloatingLiteral(ASTContext &C, EmptyShell Empty);
+  explicit FloatingLiteral(const ASTContext &C, EmptyShell Empty);
 
 public:
-  static FloatingLiteral *Create(ASTContext &C, const llvm::APFloat &V,
+  static FloatingLiteral *Create(const ASTContext &C, const llvm::APFloat &V,
                                  bool isexact, QualType Type, SourceLocation L);
-  static FloatingLiteral *Create(ASTContext &C, EmptyShell Empty);
+  static FloatingLiteral *Create(const ASTContext &C, EmptyShell Empty);
 
   llvm::APFloat getValue() const {
     return APFloatStorage::getValue(getSemantics());
   }
-  void setValue(ASTContext &C, const llvm::APFloat &Val) {
+  void setValue(const ASTContext &C, const llvm::APFloat &Val) {
     assert(&getSemantics() == &Val.getSemantics() && "Inconsistent semantics");
     APFloatStorage::setValue(C, Val);
   }
@@ -1468,19 +1470,19 @@
 public:
   /// This is the "fully general" constructor that allows representation of
   /// strings formed from multiple concatenated tokens.
-  static StringLiteral *Create(ASTContext &C, StringRef Str, StringKind Kind,
-                               bool Pascal, QualType Ty,
+  static StringLiteral *Create(const ASTContext &C, StringRef Str,
+                               StringKind Kind, bool Pascal, QualType Ty,
                                const SourceLocation *Loc, unsigned NumStrs);
 
   /// Simple constructor for string literals made from one token.
-  static StringLiteral *Create(ASTContext &C, StringRef Str, StringKind Kind,
-                               bool Pascal, QualType Ty,
+  static StringLiteral *Create(const ASTContext &C, StringRef Str,
+                               StringKind Kind, bool Pascal, QualType Ty,
                                SourceLocation Loc) {
     return Create(C, Str, Kind, Pascal, Ty, &Loc, 1);
   }
 
   /// \brief Construct an empty string literal.
-  static StringLiteral *CreateEmpty(ASTContext &C, unsigned NumStrs);
+  static StringLiteral *CreateEmpty(const ASTContext &C, unsigned NumStrs);
 
   StringRef getString() const {
     assert(CharByteWidth==1
@@ -1519,7 +1521,7 @@
   unsigned getCharByteWidth() const { return CharByteWidth; }
 
   /// \brief Sets the string data to the given string data.
-  void setString(ASTContext &C, StringRef Str,
+  void setString(const ASTContext &C, StringRef Str,
                  StringKind Kind, bool IsPascal);
 
   StringKind getKind() const { return static_cast<StringKind>(Kind); }
@@ -1852,7 +1854,7 @@
   // Number of sub-expressions (i.e. array subscript expressions).
   unsigned NumExprs;
 
-  OffsetOfExpr(ASTContext &C, QualType type,
+  OffsetOfExpr(const ASTContext &C, QualType type,
                SourceLocation OperatorLoc, TypeSourceInfo *tsi,
                ArrayRef<OffsetOfNode> comps, ArrayRef<Expr*> exprs,
                SourceLocation RParenLoc);
@@ -1863,12 +1865,12 @@
 
 public:
 
-  static OffsetOfExpr *Create(ASTContext &C, QualType type,
+  static OffsetOfExpr *Create(const ASTContext &C, QualType type,
                               SourceLocation OperatorLoc, TypeSourceInfo *tsi,
                               ArrayRef<OffsetOfNode> comps,
                               ArrayRef<Expr*> exprs, SourceLocation RParenLoc);
 
-  static OffsetOfExpr *CreateEmpty(ASTContext &C,
+  static OffsetOfExpr *CreateEmpty(const ASTContext &C,
                                    unsigned NumComps, unsigned NumExprs);
 
   /// getOperatorLoc - Return the location of the operator.
@@ -2132,10 +2134,11 @@
 
 protected:
   // These versions of the constructor are for derived classes.
-  CallExpr(ASTContext& C, StmtClass SC, Expr *fn, unsigned NumPreArgs,
+  CallExpr(const ASTContext& C, StmtClass SC, Expr *fn, unsigned NumPreArgs,
            ArrayRef<Expr*> args, QualType t, ExprValueKind VK,
            SourceLocation rparenloc);
-  CallExpr(ASTContext &C, StmtClass SC, unsigned NumPreArgs, EmptyShell Empty);
+  CallExpr(const ASTContext &C, StmtClass SC, unsigned NumPreArgs,
+           EmptyShell Empty);
 
   Stmt *getPreArg(unsigned i) {
     assert(i < getNumPreArgs() && "Prearg access out of range!");
@@ -2153,11 +2156,11 @@
   unsigned getNumPreArgs() const { return CallExprBits.NumPreArgs; }
 
 public:
-  CallExpr(ASTContext& C, Expr *fn, ArrayRef<Expr*> args, QualType t,
+  CallExpr(const ASTContext& C, Expr *fn, ArrayRef<Expr*> args, QualType t,
            ExprValueKind VK, SourceLocation rparenloc);
 
   /// \brief Build an empty call expression.
-  CallExpr(ASTContext &C, StmtClass SC, EmptyShell Empty);
+  CallExpr(const ASTContext &C, StmtClass SC, EmptyShell Empty);
 
   const Expr *getCallee() const { return cast<Expr>(SubExprs[FN]); }
   Expr *getCallee() { return cast<Expr>(SubExprs[FN]); }
@@ -2205,7 +2208,7 @@
   /// setNumArgs - This changes the number of arguments present in this call.
   /// Any orphaned expressions are deleted by this, and any new operands are set
   /// to null.
-  void setNumArgs(ASTContext& C, unsigned NumArgs);
+  void setNumArgs(const ASTContext& C, unsigned NumArgs);
 
   typedef ExprIterator arg_iterator;
   typedef ConstExprIterator const_arg_iterator;
@@ -2359,7 +2362,7 @@
       HasQualifierOrFoundDecl(false), HasTemplateKWAndArgsInfo(false),
       HadMultipleCandidates(false) {}
 
-  static MemberExpr *Create(ASTContext &C, Expr *base, bool isarrow,
+  static MemberExpr *Create(const ASTContext &C, Expr *base, bool isarrow,
                             NestedNameSpecifierLoc QualifierLoc,
                             SourceLocation TemplateKWLoc,
                             ValueDecl *memberdecl, DeclAccessPair founddecl,
@@ -2746,12 +2749,13 @@
     : CastExpr(ImplicitCastExprClass, ty, VK, kind, op, 0) {
   }
 
-  static ImplicitCastExpr *Create(ASTContext &Context, QualType T,
+  static ImplicitCastExpr *Create(const ASTContext &Context, QualType T,
                                   CastKind Kind, Expr *Operand,
                                   const CXXCastPath *BasePath,
                                   ExprValueKind Cat);
 
-  static ImplicitCastExpr *CreateEmpty(ASTContext &Context, unsigned PathSize);
+  static ImplicitCastExpr *CreateEmpty(const ASTContext &Context,
+                                       unsigned PathSize);
 
   SourceLocation getLocStart() const LLVM_READONLY {
     return getSubExpr()->getLocStart();
@@ -2837,13 +2841,14 @@
     : ExplicitCastExpr(CStyleCastExprClass, Shell, PathSize) { }
 
 public:
-  static CStyleCastExpr *Create(ASTContext &Context, QualType T,
+  static CStyleCastExpr *Create(const ASTContext &Context, QualType T,
                                 ExprValueKind VK, CastKind K,
                                 Expr *Op, const CXXCastPath *BasePath,
                                 TypeSourceInfo *WrittenTy, SourceLocation L,
                                 SourceLocation R);
 
-  static CStyleCastExpr *CreateEmpty(ASTContext &Context, unsigned PathSize);
+  static CStyleCastExpr *CreateEmpty(const ASTContext &Context,
+                                     unsigned PathSize);
 
   SourceLocation getLParenLoc() const { return LPLoc; }
   void setLParenLoc(SourceLocation L) { LPLoc = L; }
@@ -3411,7 +3416,7 @@
   unsigned NumExprs;
 
 public:
-  ShuffleVectorExpr(ASTContext &C, ArrayRef<Expr*> args, QualType Type,
+  ShuffleVectorExpr(const ASTContext &C, ArrayRef<Expr*> args, QualType Type,
                     SourceLocation BLoc, SourceLocation RP);
 
   /// \brief Build an empty vector-shuffle expression.
@@ -3449,9 +3454,9 @@
     return cast<Expr>(SubExprs[Index]);
   }
 
-  void setExprs(ASTContext &C, ArrayRef<Expr *> Exprs);
+  void setExprs(const ASTContext &C, ArrayRef<Expr *> Exprs);
 
-  llvm::APSInt getShuffleMaskIdx(ASTContext &Ctx, unsigned N) const {
+  llvm::APSInt getShuffleMaskIdx(const ASTContext &Ctx, unsigned N) const {
     assert((N < NumExprs - 2) && "Shuffle idx out of range!");
     return getExpr(N+2)->EvaluateKnownConstInt(Ctx);
   }
@@ -3689,7 +3694,7 @@
   llvm::PointerUnion<Expr *, FieldDecl *> ArrayFillerOrUnionFieldInit;
 
 public:
-  InitListExpr(ASTContext &C, SourceLocation lbraceloc,
+  InitListExpr(const ASTContext &C, SourceLocation lbraceloc,
                ArrayRef<Expr*> initExprs, SourceLocation rbraceloc);
 
   /// \brief Build an empty initializer list.
@@ -3717,7 +3722,7 @@
   }
 
   /// \brief Reserve space for some number of initializers.
-  void reserveInits(ASTContext &C, unsigned NumInits);
+  void reserveInits(const ASTContext &C, unsigned NumInits);
 
   /// @brief Specify the number of initializers
   ///
@@ -3725,7 +3730,7 @@
   /// initializers will be destroyed. If there are fewer than @p
   /// NumInits initializers, NULL expressions will be added for the
   /// unknown initializers.
-  void resizeInits(ASTContext &Context, unsigned NumInits);
+  void resizeInits(const ASTContext &Context, unsigned NumInits);
 
   /// @brief Updates the initializer at index @p Init with the new
   /// expression @p expr, and returns the old expression at that
@@ -3734,7 +3739,7 @@
   /// When @p Init is out of range for this initializer list, the
   /// initializer list will be extended with NULL expressions to
   /// accommodate the new entry.
-  Expr *updateInit(ASTContext &C, unsigned Init, Expr *expr);
+  Expr *updateInit(const ASTContext &C, unsigned Init, Expr *expr);
 
   /// \brief If this initializer list initializes an array with more elements
   /// than there are initializers in the list, specifies an expression to be
@@ -3882,7 +3887,7 @@
   Designator *Designators;
 
 
-  DesignatedInitExpr(ASTContext &C, QualType Ty, unsigned NumDesignators,
+  DesignatedInitExpr(const ASTContext &C, QualType Ty, unsigned NumDesignators,
                      const Designator *Designators,
                      SourceLocation EqualOrColonLoc, bool GNUSyntax,
                      ArrayRef<Expr*> IndexExprs, Expr *Init);
@@ -4044,13 +4049,15 @@
     }
   };
 
-  static DesignatedInitExpr *Create(ASTContext &C, Designator *Designators,
+  static DesignatedInitExpr *Create(const ASTContext &C,
+                                    Designator *Designators,
                                     unsigned NumDesignators,
                                     ArrayRef<Expr*> IndexExprs,
                                     SourceLocation EqualOrColonLoc,
                                     bool GNUSyntax, Expr *Init);
 
-  static DesignatedInitExpr *CreateEmpty(ASTContext &C, unsigned NumIndexExprs);
+  static DesignatedInitExpr *CreateEmpty(const ASTContext &C,
+                                         unsigned NumIndexExprs);
 
   /// @brief Returns the number of designators in this initializer.
   unsigned size() const { return NumDesignators; }
@@ -4088,7 +4095,7 @@
 
   Designator *getDesignator(unsigned Idx) { return &designators_begin()[Idx]; }
 
-  void setDesignators(ASTContext &C, const Designator *Desigs,
+  void setDesignators(const ASTContext &C, const Designator *Desigs,
                       unsigned NumDesigs);
 
   Expr *getArrayIndex(const Designator &D) const;
@@ -4136,8 +4143,8 @@
 
   /// \brief Replaces the designator at index @p Idx with the series
   /// of designators in [First, Last).
-  void ExpandDesignator(ASTContext &C, unsigned Idx, const Designator *First,
-                        const Designator *Last);
+  void ExpandDesignator(const ASTContext &C, unsigned Idx,
+                        const Designator *First, const Designator *Last);
 
   SourceRange getDesignatorsSourceRange() const;
 
@@ -4191,8 +4198,8 @@
   SourceLocation LParenLoc, RParenLoc;
 
 public:
-  ParenListExpr(ASTContext& C, SourceLocation lparenloc, ArrayRef<Expr*> exprs,
-                SourceLocation rparenloc);
+  ParenListExpr(const ASTContext& C, SourceLocation lparenloc,
+                ArrayRef<Expr*> exprs, SourceLocation rparenloc);
 
   /// \brief Build an empty paren list.
   explicit ParenListExpr(EmptyShell Empty) : Expr(ParenListExprClass, Empty) { }
@@ -4265,7 +4272,7 @@
   SourceLocation GenericLoc, DefaultLoc, RParenLoc;
 
 public:
-  GenericSelectionExpr(ASTContext &Context,
+  GenericSelectionExpr(const ASTContext &Context,
                        SourceLocation GenericLoc, Expr *ControllingExpr,
                        ArrayRef<TypeSourceInfo*> AssocTypes,
                        ArrayRef<Expr*> AssocExprs,
@@ -4274,7 +4281,7 @@
                        unsigned ResultIndex);
 
   /// This constructor is used in the result-dependent case.
-  GenericSelectionExpr(ASTContext &Context,
+  GenericSelectionExpr(const ASTContext &Context,
                        SourceLocation GenericLoc, Expr *ControllingExpr,
                        ArrayRef<TypeSourceInfo*> AssocTypes,
                        ArrayRef<Expr*> AssocExprs,
@@ -4557,11 +4564,11 @@
   /// no semantic result.
   enum { NoResult = ~0U };
 
-  static PseudoObjectExpr *Create(ASTContext &Context, Expr *syntactic,
+  static PseudoObjectExpr *Create(const ASTContext &Context, Expr *syntactic,
                                   ArrayRef<Expr*> semantic,
                                   unsigned resultIndex);
 
-  static PseudoObjectExpr *Create(ASTContext &Context, EmptyShell shell,
+  static PseudoObjectExpr *Create(const ASTContext &Context, EmptyShell shell,
                                   unsigned numSemanticExprs);
 
   /// Return the syntactic form of this expression, i.e. the
diff --git a/include/clang/AST/Stmt.h b/include/clang/AST/Stmt.h
index dff9a1d..834a3dc 100644
--- a/include/clang/AST/Stmt.h
+++ b/include/clang/AST/Stmt.h
@@ -312,19 +312,19 @@
 public:
   // Only allow allocation of Stmts using the allocator in ASTContext
   // or by doing a placement new.
-  void* operator new(size_t bytes, ASTContext& C,
+  void* operator new(size_t bytes, const ASTContext& C,
                      unsigned alignment = 8) throw();
 
-  void* operator new(size_t bytes, ASTContext* C,
+  void* operator new(size_t bytes, const ASTContext* C,
                      unsigned alignment = 8) throw();
 
   void* operator new(size_t bytes, void* mem) throw() {
     return mem;
   }
 
-  void operator delete(void*, ASTContext&, unsigned) throw() { }
-  void operator delete(void*, ASTContext*, unsigned) throw() { }
-  void operator delete(void*, std::size_t) throw() { }
+  void operator delete(void*, const ASTContext&, unsigned) throw() { }
+  void operator delete(void*, const ASTContext*, unsigned) throw() { }
+  void operator delete(void*, size_t) throw() { }
   void operator delete(void*, void*) throw() { }
 
 public:
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 3eeb53e..6a1e500 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -622,7 +622,8 @@
   return "";
 }
 
-void APNumericStorage::setIntValue(ASTContext &C, const llvm::APInt &Val) {
+void APNumericStorage::setIntValue(const ASTContext &C,
+                                   const llvm::APInt &Val) {
   if (hasAllocation())
     C.Deallocate(pVal);
 
@@ -638,7 +639,7 @@
     VAL = 0;
 }
 
-IntegerLiteral::IntegerLiteral(ASTContext &C, const llvm::APInt &V,
+IntegerLiteral::IntegerLiteral(const ASTContext &C, const llvm::APInt &V,
                                QualType type, SourceLocation l)
   : Expr(IntegerLiteralClass, type, VK_RValue, OK_Ordinary, false, false,
          false, false),
@@ -650,17 +651,17 @@
 }
 
 IntegerLiteral *
-IntegerLiteral::Create(ASTContext &C, const llvm::APInt &V,
+IntegerLiteral::Create(const ASTContext &C, const llvm::APInt &V,
                        QualType type, SourceLocation l) {
   return new (C) IntegerLiteral(C, V, type, l);
 }
 
 IntegerLiteral *
-IntegerLiteral::Create(ASTContext &C, EmptyShell Empty) {
+IntegerLiteral::Create(const ASTContext &C, EmptyShell Empty) {
   return new (C) IntegerLiteral(Empty);
 }
 
-FloatingLiteral::FloatingLiteral(ASTContext &C, const llvm::APFloat &V,
+FloatingLiteral::FloatingLiteral(const ASTContext &C, const llvm::APFloat &V,
                                  bool isexact, QualType Type, SourceLocation L)
   : Expr(FloatingLiteralClass, Type, VK_RValue, OK_Ordinary, false, false,
          false, false), Loc(L) {
@@ -669,20 +670,20 @@
   setValue(C, V);
 }
 
-FloatingLiteral::FloatingLiteral(ASTContext &C, EmptyShell Empty)
+FloatingLiteral::FloatingLiteral(const ASTContext &C, EmptyShell Empty)
   : Expr(FloatingLiteralClass, Empty) {
   setRawSemantics(IEEEhalf);
   FloatingLiteralBits.IsExact = false;
 }
 
 FloatingLiteral *
-FloatingLiteral::Create(ASTContext &C, const llvm::APFloat &V,
+FloatingLiteral::Create(const ASTContext &C, const llvm::APFloat &V,
                         bool isexact, QualType Type, SourceLocation L) {
   return new (C) FloatingLiteral(C, V, isexact, Type, L);
 }
 
 FloatingLiteral *
-FloatingLiteral::Create(ASTContext &C, EmptyShell Empty) {
+FloatingLiteral::Create(const ASTContext &C, EmptyShell Empty) {
   return new (C) FloatingLiteral(C, Empty);
 }
 
@@ -756,7 +757,7 @@
   return CharByteWidth;
 }
 
-StringLiteral *StringLiteral::Create(ASTContext &C, StringRef Str,
+StringLiteral *StringLiteral::Create(const ASTContext &C, StringRef Str,
                                      StringKind Kind, bool Pascal, QualType Ty,
                                      const SourceLocation *Loc,
                                      unsigned NumStrs) {
@@ -778,7 +779,8 @@
   return SL;
 }
 
-StringLiteral *StringLiteral::CreateEmpty(ASTContext &C, unsigned NumStrs) {
+StringLiteral *StringLiteral::CreateEmpty(const ASTContext &C,
+                                          unsigned NumStrs) {
   void *Mem = C.Allocate(sizeof(StringLiteral)+
                          sizeof(SourceLocation)*(NumStrs-1),
                          llvm::alignOf<StringLiteral>());
@@ -882,7 +884,7 @@
   OS << '"';
 }
 
-void StringLiteral::setString(ASTContext &C, StringRef Str,
+void StringLiteral::setString(const ASTContext &C, StringRef Str,
                               StringKind Kind, bool IsPascal) {
   //FIXME: we assume that the string data comes from a target that uses the same
   // code unit size and endianess for the type of string.
@@ -1035,9 +1037,9 @@
 // Postfix Operators.
 //===----------------------------------------------------------------------===//
 
-CallExpr::CallExpr(ASTContext& C, StmtClass SC, Expr *fn, unsigned NumPreArgs,
-                   ArrayRef<Expr*> args, QualType t, ExprValueKind VK,
-                   SourceLocation rparenloc)
+CallExpr::CallExpr(const ASTContext& C, StmtClass SC, Expr *fn,
+                   unsigned NumPreArgs, ArrayRef<Expr*> args, QualType t,
+                   ExprValueKind VK, SourceLocation rparenloc)
   : Expr(SC, t, VK, OK_Ordinary,
          fn->isTypeDependent(),
          fn->isValueDependent(),
@@ -1064,7 +1066,7 @@
   RParenLoc = rparenloc;
 }
 
-CallExpr::CallExpr(ASTContext& C, Expr *fn, ArrayRef<Expr*> args,
+CallExpr::CallExpr(const ASTContext& C, Expr *fn, ArrayRef<Expr*> args,
                    QualType t, ExprValueKind VK, SourceLocation rparenloc)
   : Expr(CallExprClass, t, VK, OK_Ordinary,
          fn->isTypeDependent(),
@@ -1092,14 +1094,14 @@
   RParenLoc = rparenloc;
 }
 
-CallExpr::CallExpr(ASTContext &C, StmtClass SC, EmptyShell Empty)
+CallExpr::CallExpr(const ASTContext &C, StmtClass SC, EmptyShell Empty)
   : Expr(SC, Empty), SubExprs(0), NumArgs(0) {
   // FIXME: Why do we allocate this?
   SubExprs = new (C) Stmt*[PREARGS_START];
   CallExprBits.NumPreArgs = 0;
 }
 
-CallExpr::CallExpr(ASTContext &C, StmtClass SC, unsigned NumPreArgs,
+CallExpr::CallExpr(const ASTContext &C, StmtClass SC, unsigned NumPreArgs,
                    EmptyShell Empty)
   : Expr(SC, Empty), SubExprs(0), NumArgs(0) {
   // FIXME: Why do we allocate this?
@@ -1138,7 +1140,7 @@
 /// setNumArgs - This changes the number of arguments present in this call.
 /// Any orphaned expressions are deleted by this, and any new operands are set
 /// to null.
-void CallExpr::setNumArgs(ASTContext& C, unsigned NumArgs) {
+void CallExpr::setNumArgs(const ASTContext& C, unsigned NumArgs) {
   // No change, just return.
   if (NumArgs == getNumArgs()) return;
 
@@ -1227,7 +1229,7 @@
   return end;
 }
 
-OffsetOfExpr *OffsetOfExpr::Create(ASTContext &C, QualType type, 
+OffsetOfExpr *OffsetOfExpr::Create(const ASTContext &C, QualType type,
                                    SourceLocation OperatorLoc,
                                    TypeSourceInfo *tsi, 
                                    ArrayRef<OffsetOfNode> comps,
@@ -1241,7 +1243,7 @@
                                 RParenLoc);
 }
 
-OffsetOfExpr *OffsetOfExpr::CreateEmpty(ASTContext &C,
+OffsetOfExpr *OffsetOfExpr::CreateEmpty(const ASTContext &C,
                                         unsigned numComps, unsigned numExprs) {
   void *Mem = C.Allocate(sizeof(OffsetOfExpr) +
                          sizeof(OffsetOfNode) * numComps +
@@ -1249,7 +1251,7 @@
   return new (Mem) OffsetOfExpr(numComps, numExprs);
 }
 
-OffsetOfExpr::OffsetOfExpr(ASTContext &C, QualType type, 
+OffsetOfExpr::OffsetOfExpr(const ASTContext &C, QualType type,
                            SourceLocation OperatorLoc, TypeSourceInfo *tsi,
                            ArrayRef<OffsetOfNode> comps, ArrayRef<Expr*> exprs,
                            SourceLocation RParenLoc)
@@ -1283,7 +1285,7 @@
   return reinterpret_cast<IdentifierInfo *> (Data & ~(uintptr_t)Mask);
 }
 
-MemberExpr *MemberExpr::Create(ASTContext &C, Expr *base, bool isarrow,
+MemberExpr *MemberExpr::Create(const ASTContext &C, Expr *base, bool isarrow,
                                NestedNameSpecifierLoc QualifierLoc,
                                SourceLocation TemplateKWLoc,
                                ValueDecl *memberdecl,
@@ -1637,7 +1639,7 @@
   memcpy(path_buffer(), Path.data(), Path.size() * sizeof(CXXBaseSpecifier*));
 }
 
-ImplicitCastExpr *ImplicitCastExpr::Create(ASTContext &C, QualType T,
+ImplicitCastExpr *ImplicitCastExpr::Create(const ASTContext &C, QualType T,
                                            CastKind Kind, Expr *Operand,
                                            const CXXCastPath *BasePath,
                                            ExprValueKind VK) {
@@ -1650,7 +1652,7 @@
   return E;
 }
 
-ImplicitCastExpr *ImplicitCastExpr::CreateEmpty(ASTContext &C,
+ImplicitCastExpr *ImplicitCastExpr::CreateEmpty(const ASTContext &C,
                                                 unsigned PathSize) {
   void *Buffer =
     C.Allocate(sizeof(ImplicitCastExpr) + PathSize * sizeof(CXXBaseSpecifier*));
@@ -1658,7 +1660,7 @@
 }
 
 
-CStyleCastExpr *CStyleCastExpr::Create(ASTContext &C, QualType T,
+CStyleCastExpr *CStyleCastExpr::Create(const ASTContext &C, QualType T,
                                        ExprValueKind VK, CastKind K, Expr *Op,
                                        const CXXCastPath *BasePath,
                                        TypeSourceInfo *WrittenTy,
@@ -1672,7 +1674,8 @@
   return E;
 }
 
-CStyleCastExpr *CStyleCastExpr::CreateEmpty(ASTContext &C, unsigned PathSize) {
+CStyleCastExpr *CStyleCastExpr::CreateEmpty(const ASTContext &C,
+                                            unsigned PathSize) {
   void *Buffer =
     C.Allocate(sizeof(CStyleCastExpr) + PathSize * sizeof(CXXBaseSpecifier*));
   return new (Buffer) CStyleCastExpr(EmptyShell(), PathSize);
@@ -1781,7 +1784,7 @@
   return OverOps[Opc];
 }
 
-InitListExpr::InitListExpr(ASTContext &C, SourceLocation lbraceloc,
+InitListExpr::InitListExpr(const ASTContext &C, SourceLocation lbraceloc,
                            ArrayRef<Expr*> initExprs, SourceLocation rbraceloc)
   : Expr(InitListExprClass, QualType(), VK_RValue, OK_Ordinary, false, false,
          false, false),
@@ -1803,16 +1806,16 @@
   InitExprs.insert(C, InitExprs.end(), initExprs.begin(), initExprs.end());
 }
 
-void InitListExpr::reserveInits(ASTContext &C, unsigned NumInits) {
+void InitListExpr::reserveInits(const ASTContext &C, unsigned NumInits) {
   if (NumInits > InitExprs.size())
     InitExprs.reserve(C, NumInits);
 }
 
-void InitListExpr::resizeInits(ASTContext &C, unsigned NumInits) {
+void InitListExpr::resizeInits(const ASTContext &C, unsigned NumInits) {
   InitExprs.resize(C, NumInits, 0);
 }
 
-Expr *InitListExpr::updateInit(ASTContext &C, unsigned Init, Expr *expr) {
+Expr *InitListExpr::updateInit(const ASTContext &C, unsigned Init, Expr *expr) {
   if (Init >= InitExprs.size()) {
     InitExprs.insert(C, InitExprs.end(), Init - InitExprs.size() + 1, 0);
     InitExprs.back() = expr;
@@ -3531,7 +3534,7 @@
   llvm_unreachable("Invalid BridgeKind!");
 }
 
-ShuffleVectorExpr::ShuffleVectorExpr(ASTContext &C, ArrayRef<Expr*> args,
+ShuffleVectorExpr::ShuffleVectorExpr(const ASTContext &C, ArrayRef<Expr*> args,
                                      QualType Type, SourceLocation BLoc,
                                      SourceLocation RP) 
    : Expr(ShuffleVectorExprClass, Type, VK_RValue, OK_Ordinary,
@@ -3555,7 +3558,7 @@
   }
 }
 
-void ShuffleVectorExpr::setExprs(ASTContext &C, ArrayRef<Expr *> Exprs) {
+void ShuffleVectorExpr::setExprs(const ASTContext &C, ArrayRef<Expr *> Exprs) {
   if (SubExprs) C.Deallocate(SubExprs);
 
   this->NumExprs = Exprs.size();
@@ -3563,7 +3566,7 @@
   memcpy(SubExprs, Exprs.data(), sizeof(Expr *) * Exprs.size());
 }
 
-GenericSelectionExpr::GenericSelectionExpr(ASTContext &Context,
+GenericSelectionExpr::GenericSelectionExpr(const ASTContext &Context,
                                SourceLocation GenericLoc, Expr *ControllingExpr,
                                ArrayRef<TypeSourceInfo*> AssocTypes,
                                ArrayRef<Expr*> AssocExprs,
@@ -3589,7 +3592,7 @@
   std::copy(AssocExprs.begin(), AssocExprs.end(), SubExprs+END_EXPR);
 }
 
-GenericSelectionExpr::GenericSelectionExpr(ASTContext &Context,
+GenericSelectionExpr::GenericSelectionExpr(const ASTContext &Context,
                                SourceLocation GenericLoc, Expr *ControllingExpr,
                                ArrayRef<TypeSourceInfo*> AssocTypes,
                                ArrayRef<Expr*> AssocExprs,
@@ -3626,7 +3629,7 @@
     return getField()->getIdentifier();
 }
 
-DesignatedInitExpr::DesignatedInitExpr(ASTContext &C, QualType Ty, 
+DesignatedInitExpr::DesignatedInitExpr(const ASTContext &C, QualType Ty,
                                        unsigned NumDesignators,
                                        const Designator *Designators,
                                        SourceLocation EqualOrColonLoc,
@@ -3693,7 +3696,7 @@
 }
 
 DesignatedInitExpr *
-DesignatedInitExpr::Create(ASTContext &C, Designator *Designators,
+DesignatedInitExpr::Create(const ASTContext &C, Designator *Designators,
                            unsigned NumDesignators,
                            ArrayRef<Expr*> IndexExprs,
                            SourceLocation ColonOrEqualLoc,
@@ -3705,14 +3708,14 @@
                                       IndexExprs, Init);
 }
 
-DesignatedInitExpr *DesignatedInitExpr::CreateEmpty(ASTContext &C,
+DesignatedInitExpr *DesignatedInitExpr::CreateEmpty(const ASTContext &C,
                                                     unsigned NumIndexExprs) {
   void *Mem = C.Allocate(sizeof(DesignatedInitExpr) +
                          sizeof(Stmt *) * (NumIndexExprs + 1), 8);
   return new (Mem) DesignatedInitExpr(NumIndexExprs + 1);
 }
 
-void DesignatedInitExpr::setDesignators(ASTContext &C,
+void DesignatedInitExpr::setDesignators(const ASTContext &C,
                                         const Designator *Desigs,
                                         unsigned NumDesigs) {
   Designators = new (C) Designator[NumDesigs];
@@ -3779,7 +3782,7 @@
 
 /// \brief Replaces the designator at index @p Idx with the series
 /// of designators in [First, Last).
-void DesignatedInitExpr::ExpandDesignator(ASTContext &C, unsigned Idx,
+void DesignatedInitExpr::ExpandDesignator(const ASTContext &C, unsigned Idx,
                                           const Designator *First,
                                           const Designator *Last) {
   unsigned NumNewDesignators = Last - First;
@@ -3804,7 +3807,7 @@
   NumDesignators = NumDesignators - 1 + NumNewDesignators;
 }
 
-ParenListExpr::ParenListExpr(ASTContext& C, SourceLocation lparenloc,
+ParenListExpr::ParenListExpr(const ASTContext& C, SourceLocation lparenloc,
                              ArrayRef<Expr*> exprs,
                              SourceLocation rparenloc)
   : Expr(ParenListExprClass, QualType(), VK_RValue, OK_Ordinary,
@@ -3836,7 +3839,8 @@
   return cast<OpaqueValueExpr>(e);
 }
 
-PseudoObjectExpr *PseudoObjectExpr::Create(ASTContext &Context, EmptyShell sh,
+PseudoObjectExpr *PseudoObjectExpr::Create(const ASTContext &Context,
+                                           EmptyShell sh,
                                            unsigned numSemanticExprs) {
   void *buffer = Context.Allocate(sizeof(PseudoObjectExpr) +
                                     (1 + numSemanticExprs) * sizeof(Expr*),
@@ -3849,7 +3853,7 @@
   PseudoObjectExprBits.NumSubExprs = numSemanticExprs + 1;
 }
 
-PseudoObjectExpr *PseudoObjectExpr::Create(ASTContext &C, Expr *syntax,
+PseudoObjectExpr *PseudoObjectExpr::Create(const ASTContext &C, Expr *syntax,
                                            ArrayRef<Expr*> semantics,
                                            unsigned resultIndex) {
   assert(syntax && "no syntactic expression!");
diff --git a/lib/AST/Stmt.cpp b/lib/AST/Stmt.cpp
index 6a39996..87e55a2 100644
--- a/lib/AST/Stmt.cpp
+++ b/lib/AST/Stmt.cpp
@@ -49,12 +49,12 @@
   return StmtClassInfo[E];
 }
 
-void *Stmt::operator new(size_t bytes, ASTContext& C,
+void *Stmt::operator new(size_t bytes, const ASTContext& C,
                          unsigned alignment) throw() {
   return ::operator new(bytes, C, alignment);
 }
 
-void *Stmt::operator new(size_t bytes, ASTContext* C,
+void *Stmt::operator new(size_t bytes, const ASTContext* C,
                          unsigned alignment) throw() {
   return ::operator new(bytes, *C, alignment);
 }