diff --git a/include/llvm/DerivedTypes.h b/include/llvm/DerivedTypes.h
index 0f1e99f..0fc2c3a 100644
--- a/include/llvm/DerivedTypes.h
+++ b/include/llvm/DerivedTypes.h
@@ -103,6 +103,8 @@
   /// a FunctionType.
   ///
   static FunctionType *get(const Type *Result,
+                           ArrayRef<const Type*> Params, bool isVarArg);
+  static FunctionType *get(const Type *Result,
                            ArrayRef<Type*> Params, bool isVarArg);
 
   /// FunctionType::get - Create a FunctionType taking no parameters.
@@ -204,6 +206,11 @@
 
   /// StructType::get - This static method is the primary way to create a
   /// StructType.
+  ///
+  /// FIXME: Remove the 'const Type*' version of this when types are pervasively
+  /// de-constified.
+  static StructType *get(LLVMContext &Context, ArrayRef<const Type*> Elements,
+                         bool isPacked = false);
   static StructType *get(LLVMContext &Context, ArrayRef<Type*> Elements,
                          bool isPacked = false);
 
@@ -215,7 +222,7 @@
   /// structure types by specifying the elements as arguments.  Note that this
   /// method always returns a non-packed struct, and requires at least one
   /// element type.
-  static StructType *get(Type *elt1, ...) END_WITH_NULL;
+  static StructType *get(const Type *elt1, ...) END_WITH_NULL;
 
   bool isPacked() const { return (getSubclassData() & SCDB_Packed) != 0; }
   
diff --git a/include/llvm/Intrinsics.h b/include/llvm/Intrinsics.h
index 4885e28..5cfe551 100644
--- a/include/llvm/Intrinsics.h
+++ b/include/llvm/Intrinsics.h
@@ -44,12 +44,12 @@
   
   /// Intrinsic::getName(ID) - Return the LLVM name for an intrinsic, such as
   /// "llvm.ppc.altivec.lvx".
-  std::string getName(ID id, Type **Tys = 0, unsigned numTys = 0);
+  std::string getName(ID id, const Type **Tys = 0, unsigned numTys = 0);
   
   /// Intrinsic::getType(ID) - Return the function type for an intrinsic.
   ///
   const FunctionType *getType(LLVMContext &Context, ID id,
-                              Type **Tys = 0, unsigned numTys = 0);
+                              const Type **Tys = 0, unsigned numTys = 0);
 
   /// Intrinsic::isOverloaded(ID) - Returns true if the intrinsic can be
   /// overloaded.
@@ -67,7 +67,7 @@
   /// overloaded intrinsic, Tys should point to an array of numTys pointers to
   /// Type, and must provide exactly one type for each overloaded type in the
   /// intrinsic.
-  Function *getDeclaration(Module *M, ID id, Type **Tys = 0, 
+  Function *getDeclaration(Module *M, ID id, const Type **Tys = 0, 
                            unsigned numTys = 0);
                            
   /// Map a GCC builtin name to an intrinsic ID.
diff --git a/include/llvm/Support/TypeBuilder.h b/include/llvm/Support/TypeBuilder.h
index 1800778..dbe7cfd 100644
--- a/include/llvm/Support/TypeBuilder.h
+++ b/include/llvm/Support/TypeBuilder.h
@@ -51,7 +51,7 @@
 ///   namespace llvm {
 ///   template<bool xcompile> class TypeBuilder<MyType, xcompile> {
 ///   public:
-///     static StructType *get(LLVMContext &Context) {
+///     static const StructType *get(LLVMContext &Context) {
 ///       // If you cache this result, be sure to cache it separately
 ///       // for each LLVMContext.
 ///       return StructType::get(
@@ -104,7 +104,7 @@
 // Pointers
 template<typename T, bool cross> class TypeBuilder<T*, cross> {
 public:
-  static PointerType *get(LLVMContext &Context) {
+  static const PointerType *get(LLVMContext &Context) {
     return PointerType::getUnqual(TypeBuilder<T,cross>::get(Context));
   }
 };
@@ -115,14 +115,14 @@
 // Arrays
 template<typename T, size_t N, bool cross> class TypeBuilder<T[N], cross> {
 public:
-  static ArrayType *get(LLVMContext &Context) {
+  static const ArrayType *get(LLVMContext &Context) {
     return ArrayType::get(TypeBuilder<T, cross>::get(Context), N);
   }
 };
 /// LLVM uses an array of length 0 to represent an unknown-length array.
 template<typename T, bool cross> class TypeBuilder<T[], cross> {
 public:
-  static ArrayType *get(LLVMContext &Context) {
+  static const ArrayType *get(LLVMContext &Context) {
     return ArrayType::get(TypeBuilder<T, cross>::get(Context), 0);
   }
 };
@@ -152,7 +152,7 @@
 #define DEFINE_INTEGRAL_TYPEBUILDER(T) \
 template<> class TypeBuilder<T, false> { \
 public: \
-  static IntegerType *get(LLVMContext &Context) { \
+  static const IntegerType *get(LLVMContext &Context) { \
     return IntegerType::get(Context, sizeof(T) * CHAR_BIT); \
   } \
 }; \
@@ -181,14 +181,14 @@
 template<uint32_t num_bits, bool cross>
 class TypeBuilder<types::i<num_bits>, cross> {
 public:
-  static IntegerType *get(LLVMContext &C) {
+  static const IntegerType *get(LLVMContext &C) {
     return IntegerType::get(C, num_bits);
   }
 };
 
 template<> class TypeBuilder<float, false> {
 public:
-  static Type *get(LLVMContext& C) {
+  static const Type *get(LLVMContext& C) {
     return Type::getFloatTy(C);
   }
 };
@@ -196,7 +196,7 @@
 
 template<> class TypeBuilder<double, false> {
 public:
-  static Type *get(LLVMContext& C) {
+  static const Type *get(LLVMContext& C) {
     return Type::getDoubleTy(C);
   }
 };
@@ -204,32 +204,32 @@
 
 template<bool cross> class TypeBuilder<types::ieee_float, cross> {
 public:
-  static Type *get(LLVMContext& C) { return Type::getFloatTy(C); }
+  static const Type *get(LLVMContext& C) { return Type::getFloatTy(C); }
 };
 template<bool cross> class TypeBuilder<types::ieee_double, cross> {
 public:
-  static Type *get(LLVMContext& C) { return Type::getDoubleTy(C); }
+  static const Type *get(LLVMContext& C) { return Type::getDoubleTy(C); }
 };
 template<bool cross> class TypeBuilder<types::x86_fp80, cross> {
 public:
-  static Type *get(LLVMContext& C) { return Type::getX86_FP80Ty(C); }
+  static const Type *get(LLVMContext& C) { return Type::getX86_FP80Ty(C); }
 };
 template<bool cross> class TypeBuilder<types::fp128, cross> {
 public:
-  static Type *get(LLVMContext& C) { return Type::getFP128Ty(C); }
+  static const Type *get(LLVMContext& C) { return Type::getFP128Ty(C); }
 };
 template<bool cross> class TypeBuilder<types::ppc_fp128, cross> {
 public:
-  static Type *get(LLVMContext& C) { return Type::getPPC_FP128Ty(C); }
+  static const Type *get(LLVMContext& C) { return Type::getPPC_FP128Ty(C); }
 };
 template<bool cross> class TypeBuilder<types::x86_mmx, cross> {
 public:
-  static Type *get(LLVMContext& C) { return Type::getX86_MMXTy(C); }
+  static const Type *get(LLVMContext& C) { return Type::getX86_MMXTy(C); }
 };
 
 template<bool cross> class TypeBuilder<void, cross> {
 public:
-  static Type *get(LLVMContext &C) {
+  static const Type *get(LLVMContext &C) {
     return Type::getVoidTy(C);
   }
 };
@@ -247,14 +247,14 @@
 
 template<typename R, bool cross> class TypeBuilder<R(), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
+  static const FunctionType *get(LLVMContext &Context) {
     return FunctionType::get(TypeBuilder<R, cross>::get(Context), false);
   }
 };
 template<typename R, typename A1, bool cross> class TypeBuilder<R(A1), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(1);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     return FunctionType::get(TypeBuilder<R, cross>::get(Context),
@@ -264,8 +264,8 @@
 template<typename R, typename A1, typename A2, bool cross>
 class TypeBuilder<R(A1, A2), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(2);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
@@ -276,8 +276,8 @@
 template<typename R, typename A1, typename A2, typename A3, bool cross>
 class TypeBuilder<R(A1, A2, A3), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(3);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
@@ -291,8 +291,8 @@
          bool cross>
 class TypeBuilder<R(A1, A2, A3, A4), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(4);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
@@ -307,8 +307,8 @@
          typename A5, bool cross>
 class TypeBuilder<R(A1, A2, A3, A4, A5), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(5);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
@@ -322,15 +322,15 @@
 
 template<typename R, bool cross> class TypeBuilder<R(...), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
+  static const FunctionType *get(LLVMContext &Context) {
     return FunctionType::get(TypeBuilder<R, cross>::get(Context), true);
   }
 };
 template<typename R, typename A1, bool cross>
 class TypeBuilder<R(A1, ...), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(1);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     return FunctionType::get(TypeBuilder<R, cross>::get(Context), params, true);
@@ -339,8 +339,8 @@
 template<typename R, typename A1, typename A2, bool cross>
 class TypeBuilder<R(A1, A2, ...), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(2);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
@@ -351,8 +351,8 @@
 template<typename R, typename A1, typename A2, typename A3, bool cross>
 class TypeBuilder<R(A1, A2, A3, ...), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(3);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
@@ -366,8 +366,8 @@
          bool cross>
 class TypeBuilder<R(A1, A2, A3, A4, ...), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(4);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
@@ -382,8 +382,8 @@
          typename A5, bool cross>
 class TypeBuilder<R(A1, A2, A3, A4, A5, ...), cross> {
 public:
-  static FunctionType *get(LLVMContext &Context) {
-    std::vector<Type*> params;
+  static const FunctionType *get(LLVMContext &Context) {
+    std::vector<const Type*> params;
     params.reserve(5);
     params.push_back(TypeBuilder<A1, cross>::get(Context));
     params.push_back(TypeBuilder<A2, cross>::get(Context));
diff --git a/include/llvm/Target/TargetData.h b/include/llvm/Target/TargetData.h
index 1025286..32e3e2b 100644
--- a/include/llvm/Target/TargetData.h
+++ b/include/llvm/Target/TargetData.h
@@ -259,7 +259,7 @@
   /// getIntPtrType - Return an unsigned integer type that is the same size or
   /// greater to the host pointer size.
   ///
-  IntegerType *getIntPtrType(LLVMContext &C) const;
+  const IntegerType *getIntPtrType(LLVMContext &C) const;
 
   /// getIndexedOffset - return the offset from the beginning of the type for
   /// the specified indices.  This is used to implement getelementptr.
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 4b066fe..881b3e9 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -1442,7 +1442,7 @@
                    "argument attributes invalid in function type");
   }
 
-  SmallVector<Type*, 16> ArgListTy;
+  SmallVector<const Type*, 16> ArgListTy;
   for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
     ArgListTy.push_back(ArgList[i].Ty);
 
@@ -2655,7 +2655,7 @@
 
   // Okay, if we got here, the function is syntactically valid.  Convert types
   // and do semantic checks.
-  std::vector<Type*> ParamTypeList;
+  std::vector<const Type*> ParamTypeList;
   SmallVector<AttributeWithIndex, 8> Attrs;
 
   if (RetAttrs != Attribute::None)
@@ -3171,7 +3171,7 @@
   if (!(PFTy = dyn_cast<PointerType>(RetType)) ||
       !(Ty = dyn_cast<FunctionType>(PFTy->getElementType()))) {
     // Pull out the types of all of the arguments...
-    std::vector<Type*> ParamTypes;
+    std::vector<const Type*> ParamTypes;
     for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
       ParamTypes.push_back(ArgList[i].V->getType());
 
@@ -3508,7 +3508,7 @@
   if (!(PFTy = dyn_cast<PointerType>(RetType)) ||
       !(Ty = dyn_cast<FunctionType>(PFTy->getElementType()))) {
     // Pull out the types of all of the arguments...
-    std::vector<Type*> ParamTypes;
+    std::vector<const Type*> ParamTypes;
     for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
       ParamTypes.push_back(ArgList[i].V->getType());
 
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 0a5ba45..1bdcfe9 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -582,7 +582,7 @@
       // FUNCTION: [vararg, attrid, retty, paramty x N]
       if (Record.size() < 3)
         return Error("Invalid FUNCTION type record");
-      std::vector<Type*> ArgTys;
+      std::vector<const Type*> ArgTys;
       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
           ArgTys.push_back(T);
@@ -838,7 +838,7 @@
       // FUNCTION: [vararg, attrid, retty, paramty x N]
       if (Record.size() < 3)
         return Error("Invalid FUNCTION type record");
-      std::vector<Type*> ArgTys;
+      std::vector<const Type*> ArgTys;
       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
         if (Type *Elt = getTypeByIDOrNull(Record[i]))
           ArgTys.push_back(Elt);
diff --git a/lib/CodeGen/DwarfEHPrepare.cpp b/lib/CodeGen/DwarfEHPrepare.cpp
index 46a8884..22c5465 100644
--- a/lib/CodeGen/DwarfEHPrepare.cpp
+++ b/lib/CodeGen/DwarfEHPrepare.cpp
@@ -497,8 +497,10 @@
   // Find the rewind function if we didn't already.
   if (!RewindFunction) {
     LLVMContext &Ctx = ResumeInsts[0]->getContext();
+    std::vector<const Type*>
+      Params(1, Type::getInt8PtrTy(Ctx));
     FunctionType *FTy = FunctionType::get(Type::getVoidTy(Ctx),
-                                          Type::getInt8PtrTy(Ctx), false);
+                                          Params, false);
     const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
     RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
   }
diff --git a/lib/CodeGen/IntrinsicLowering.cpp b/lib/CodeGen/IntrinsicLowering.cpp
index a1166d0..b0a8230 100644
--- a/lib/CodeGen/IntrinsicLowering.cpp
+++ b/lib/CodeGen/IntrinsicLowering.cpp
@@ -29,7 +29,7 @@
                                  ArgIt ArgBegin, ArgIt ArgEnd,
                                  const Type *RetTy) {
   // Insert a correctly-typed definition now.
-  std::vector<Type *> ParamTys;
+  std::vector<const Type *> ParamTys;
   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
     ParamTys.push_back(I->getType());
   M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
@@ -69,7 +69,7 @@
   // program already contains a function with this name.
   Module *M = CI->getParent()->getParent()->getParent();
   // Get or insert the definition now.
-  std::vector<Type *> ParamTys;
+  std::vector<const Type *> ParamTys;
   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
     ParamTys.push_back((*I)->getType());
   Constant* FCache = M->getOrInsertFunction(NewFn,
@@ -553,12 +553,12 @@
       !CI->getType()->isIntegerTy())
     return false;
 
-  IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
+  const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
   if (!Ty)
     return false;
 
   // Okay, we can do this xform, do so now.
-  Type *Tys[] = { Ty };
+  const Type *Tys[] = { Ty };
   Module *M = CI->getParent()->getParent()->getParent();
   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 
diff --git a/lib/CodeGen/SjLjEHPrepare.cpp b/lib/CodeGen/SjLjEHPrepare.cpp
index 65a33da..c2565af 100644
--- a/lib/CodeGen/SjLjEHPrepare.cpp
+++ b/lib/CodeGen/SjLjEHPrepare.cpp
@@ -87,8 +87,9 @@
 bool SjLjEHPass::doInitialization(Module &M) {
   // Build the function context structure.
   // builtin_setjmp uses a five word jbuf
-  Type *VoidPtrTy = Type::getInt8PtrTy(M.getContext());
-  Type *Int32Ty = Type::getInt32Ty(M.getContext());
+  const Type *VoidPtrTy =
+          Type::getInt8PtrTy(M.getContext());
+  const Type *Int32Ty = Type::getInt32Ty(M.getContext());
   FunctionContextTy =
     StructType::get(VoidPtrTy,                        // __prev
                     Int32Ty,                          // call_site
diff --git a/lib/Target/ARM/ARMGlobalMerge.cpp b/lib/Target/ARM/ARMGlobalMerge.cpp
index 8d77b2d..f899379 100644
--- a/lib/Target/ARM/ARMGlobalMerge.cpp
+++ b/lib/Target/ARM/ARMGlobalMerge.cpp
@@ -128,10 +128,10 @@
   for (size_t i = 0, e = Globals.size(); i != e; ) {
     size_t j = 0;
     uint64_t MergedSize = 0;
-    std::vector<Type*> Tys;
+    std::vector<const Type*> Tys;
     std::vector<Constant*> Inits;
     for (j = i; j != e; ++j) {
-      Type *Ty = Globals[j]->getType()->getElementType();
+      const Type *Ty = Globals[j]->getType()->getElementType();
       MergedSize += TD->getTypeAllocSize(Ty);
       if (MergedSize > MaxOffset) {
         break;
diff --git a/lib/Target/Blackfin/BlackfinIntrinsicInfo.cpp b/lib/Target/Blackfin/BlackfinIntrinsicInfo.cpp
index ae8ee9e..34a8d38 100644
--- a/lib/Target/Blackfin/BlackfinIntrinsicInfo.cpp
+++ b/lib/Target/Blackfin/BlackfinIntrinsicInfo.cpp
@@ -83,7 +83,7 @@
 
 static const FunctionType *getType(LLVMContext &Context, unsigned id) {
   const Type *ResultTy = NULL;
-  std::vector<Type*> ArgTys;
+  std::vector<const Type*> ArgTys;
   bool IsVarArg = false;
   
 #define GET_INTRINSIC_GENERATOR
diff --git a/lib/Target/MBlaze/MBlazeIntrinsicInfo.cpp b/lib/Target/MBlaze/MBlazeIntrinsicInfo.cpp
index 32d67b2..7e4a2f5 100644
--- a/lib/Target/MBlaze/MBlazeIntrinsicInfo.cpp
+++ b/lib/Target/MBlaze/MBlazeIntrinsicInfo.cpp
@@ -92,7 +92,7 @@
 
 static const FunctionType *getType(LLVMContext &Context, unsigned id) {
   const Type *ResultTy = NULL;
-  std::vector<Type*> ArgTys;
+  std::vector<const Type*> ArgTys;
   bool IsVarArg = false;
 
 #define GET_INTRINSIC_GENERATOR
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index b2c4b21..6309a15 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -535,7 +535,7 @@
 
 /// getIntPtrType - Return an unsigned integer type that is the same size or
 /// greater to the host pointer size.
-IntegerType *TargetData::getIntPtrType(LLVMContext &C) const {
+const IntegerType *TargetData::getIntPtrType(LLVMContext &C) const {
   return IntegerType::get(C, getPointerSizeInBits());
 }
 
diff --git a/lib/Transforms/IPO/ArgumentPromotion.cpp b/lib/Transforms/IPO/ArgumentPromotion.cpp
index 3288ee5..54a7f67 100644
--- a/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -493,7 +493,7 @@
   // Start by computing a new prototype for the function, which is the same as
   // the old function, but has modified arguments.
   const FunctionType *FTy = F->getFunctionType();
-  std::vector<Type*> Params;
+  std::vector<const Type*> Params;
 
   typedef std::set<IndicesVector> ScalarizeTable;
 
diff --git a/lib/Transforms/IPO/DeadArgumentElimination.cpp b/lib/Transforms/IPO/DeadArgumentElimination.cpp
index bbb386c..d4eaf0c 100644
--- a/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ b/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -208,7 +208,7 @@
   // the old function, but doesn't have isVarArg set.
   const FunctionType *FTy = Fn.getFunctionType();
 
-  std::vector<Type*> Params(FTy->param_begin(), FTy->param_end());
+  std::vector<const Type*> Params(FTy->param_begin(), FTy->param_end());
   FunctionType *NFTy = FunctionType::get(FTy->getReturnType(),
                                                 Params, false);
   unsigned NumArgs = Params.size();
@@ -647,7 +647,7 @@
   // Start by computing a new prototype for the function, which is the same as
   // the old function, but has fewer arguments and a different return type.
   const FunctionType *FTy = F->getFunctionType();
-  std::vector<Type*> Params;
+  std::vector<const Type*> Params;
 
   // Set up to build a new list of parameter attributes.
   SmallVector<AttributeWithIndex, 8> AttributesVec;
@@ -659,13 +659,13 @@
 
   // Find out the new return value.
 
-  Type *RetTy = FTy->getReturnType();
+  const Type *RetTy = FTy->getReturnType();
   const Type *NRetTy = NULL;
   unsigned RetCount = NumRetVals(F);
 
   // -1 means unused, other numbers are the new index
   SmallVector<int, 5> NewRetIdxs(RetCount, -1);
-  std::vector<Type*> RetTypes;
+  std::vector<const Type*> RetTypes;
   if (RetTy->isVoidTy()) {
     NRetTy = RetTy;
   } else {
diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 1dfbd3e..a08446e 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1400,7 +1400,7 @@
 /// MatchBSwap - Given an OR instruction, check to see if this is a bswap idiom.
 /// If so, insert the new bswap intrinsic and return it.
 Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) {
-  IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
+  const IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
   if (!ITy || ITy->getBitWidth() % 16 || 
       // ByteMask only allows up to 32-byte values.
       ITy->getBitWidth() > 32*8) 
@@ -1424,7 +1424,7 @@
   for (unsigned i = 1, e = ByteValues.size(); i != e; ++i)
     if (ByteValues[i] != V)
       return 0;
-  Type *Tys[] = { ITy };
+  const Type *Tys[] = { ITy };
   Module *M = I.getParent()->getParent()->getParent();
   Function *F = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
   return CallInst::Create(F, V);
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index b484365..27e15c3 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -217,9 +217,9 @@
         if (GVSrc->isConstant()) {
           Module *M = CI.getParent()->getParent()->getParent();
           Intrinsic::ID MemCpyID = Intrinsic::memcpy;
-          Type *Tys[3] = { CI.getArgOperand(0)->getType(),
-                           CI.getArgOperand(1)->getType(),
-                           CI.getArgOperand(2)->getType() };
+          const Type *Tys[3] = { CI.getArgOperand(0)->getType(),
+                                 CI.getArgOperand(1)->getType(),
+                                 CI.getArgOperand(2)->getType() };
           CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys, 3));
           Changed = true;
         }
@@ -1187,7 +1187,7 @@
   const AttrListPtr &NestAttrs = NestF->getAttributes();
   if (!NestAttrs.isEmpty()) {
     unsigned NestIdx = 1;
-    Type *NestTy = 0;
+    const Type *NestTy = 0;
     Attributes NestAttr = Attribute::None;
 
     // Look for a parameter marked with the 'nest' attribute.
@@ -1249,7 +1249,7 @@
       // Handle this by synthesizing a new function type, equal to FTy
       // with the chain parameter inserted.
 
-      std::vector<Type*> NewTypes;
+      std::vector<const Type*> NewTypes;
       NewTypes.reserve(FTy->getNumParams()+1);
 
       // Insert the chain's type into the list of parameter types, which may
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 3cdb705..5a1e2b0 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1683,7 +1683,7 @@
   // result and the overflow bit.
   Module *M = I.getParent()->getParent()->getParent();
   
-  Type *NewType = IntegerType::get(OrigAdd->getContext(), NewWidth);
+  const Type *NewType = IntegerType::get(OrigAdd->getContext(), NewWidth);
   Value *F = Intrinsic::getDeclaration(M, Intrinsic::sadd_with_overflow,
                                        &NewType, 1);
 
@@ -1725,7 +1725,7 @@
   Builder->SetInsertPoint(OrigAdd);
 
   Module *M = I.getParent()->getParent()->getParent();
-  Type *Ty = LHS->getType();
+  const Type *Ty = LHS->getType();
   Value *F = Intrinsic::getDeclaration(M, Intrinsic::uadd_with_overflow, &Ty,1);
   CallInst *Call = Builder->CreateCall2(F, LHS, RHS, "uadd");
   Value *Add = Builder->CreateExtractValue(Call, 0);
diff --git a/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index 3f2c412..07d69e8 100644
--- a/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -572,13 +572,14 @@
 }
 
 Constant *GCOVProfiler::getStartFileFunc() {
+  const Type *Args[] = { Type::getInt8PtrTy(*Ctx) };
   const FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx),
-                                              Type::getInt8PtrTy(*Ctx), false);
+                                              Args, false);
   return M->getOrInsertFunction("llvm_gcda_start_file", FTy);
 }
 
 Constant *GCOVProfiler::getIncrementIndirectCounterFunc() {
-  Type *Args[] = {
+  const Type *Args[] = {
     Type::getInt32PtrTy(*Ctx),                  // uint32_t *predecessor
     Type::getInt64PtrTy(*Ctx)->getPointerTo(),  // uint64_t **state_table_row
   };
@@ -588,7 +589,7 @@
 }
 
 Constant *GCOVProfiler::getEmitFunctionFunc() {
-  Type *Args[2] = {
+  const Type *Args[2] = {
     Type::getInt32Ty(*Ctx),    // uint32_t ident
     Type::getInt8PtrTy(*Ctx),  // const char *function_name
   };
@@ -598,7 +599,7 @@
 }
 
 Constant *GCOVProfiler::getEmitArcsFunc() {
-  Type *Args[] = {
+  const Type *Args[] = {
     Type::getInt32Ty(*Ctx),     // uint32_t num_counters
     Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
   };
diff --git a/lib/Transforms/Instrumentation/ProfilingUtils.cpp b/lib/Transforms/Instrumentation/ProfilingUtils.cpp
index 327e423..4224ee3 100644
--- a/lib/Transforms/Instrumentation/ProfilingUtils.cpp
+++ b/lib/Transforms/Instrumentation/ProfilingUtils.cpp
@@ -134,7 +134,7 @@
 void llvm::InsertProfilingShutdownCall(Function *Callee, Module *Mod) {
   // llvm.global_dtors is an array of type { i32, void ()* }. Prepare those
   // types.
-  Type *GlobalDtorElems[2] = {
+  const Type *GlobalDtorElems[2] = {
     Type::getInt32Ty(Mod->getContext()),
     FunctionType::get(Type::getVoidTy(Mod->getContext()), false)->getPointerTo()
   };
diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index a3a3063..bd4c2d6 100644
--- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -840,9 +840,9 @@
   
   // If not, then we know we can transform this.
   Module *Mod = M->getParent()->getParent()->getParent();
-  Type *ArgTys[3] = { M->getRawDest()->getType(),
-                      M->getRawSource()->getType(),
-                      M->getLength()->getType() };
+  const Type *ArgTys[3] = { M->getRawDest()->getType(),
+                            M->getRawSource()->getType(),
+                            M->getLength()->getType() };
   M->setCalledFunction(Intrinsic::getDeclaration(Mod, Intrinsic::memcpy,
                                                  ArgTys, 3));
 
diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
index 6e3e0f8..89a451e 100644
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/lib/Transforms/Scalar/ObjCARC.cpp
@@ -1498,8 +1498,8 @@
 Constant *ObjCARCOpt::getRetainRVCallee(Module *M) {
   if (!RetainRVCallee) {
     LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    std::vector<Type *> Params;
+    const Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
+    std::vector<const Type *> Params;
     Params.push_back(I8X);
     const FunctionType *FTy =
       FunctionType::get(I8X, Params, /*isVarArg=*/false);
@@ -1515,8 +1515,8 @@
 Constant *ObjCARCOpt::getAutoreleaseRVCallee(Module *M) {
   if (!AutoreleaseRVCallee) {
     LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    std::vector<Type *> Params;
+    const Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
+    std::vector<const Type *> Params;
     Params.push_back(I8X);
     const FunctionType *FTy =
       FunctionType::get(I8X, Params, /*isVarArg=*/false);
@@ -1532,7 +1532,7 @@
 Constant *ObjCARCOpt::getReleaseCallee(Module *M) {
   if (!ReleaseCallee) {
     LLVMContext &C = M->getContext();
-    std::vector<Type *> Params;
+    std::vector<const Type *> Params;
     Params.push_back(PointerType::getUnqual(Type::getInt8Ty(C)));
     AttrListPtr Attributes;
     Attributes.addAttr(~0u, Attribute::NoUnwind);
@@ -1548,7 +1548,7 @@
 Constant *ObjCARCOpt::getRetainCallee(Module *M) {
   if (!RetainCallee) {
     LLVMContext &C = M->getContext();
-    std::vector<Type *> Params;
+    std::vector<const Type *> Params;
     Params.push_back(PointerType::getUnqual(Type::getInt8Ty(C)));
     AttrListPtr Attributes;
     Attributes.addAttr(~0u, Attribute::NoUnwind);
@@ -1564,7 +1564,7 @@
 Constant *ObjCARCOpt::getAutoreleaseCallee(Module *M) {
   if (!AutoreleaseCallee) {
     LLVMContext &C = M->getContext();
-    std::vector<Type *> Params;
+    std::vector<const Type *> Params;
     Params.push_back(PointerType::getUnqual(Type::getInt8Ty(C)));
     AttrListPtr Attributes;
     Attributes.addAttr(~0u, Attribute::NoUnwind);
@@ -3269,9 +3269,9 @@
 Constant *ObjCARCContract::getStoreStrongCallee(Module *M) {
   if (!StoreStrongCallee) {
     LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    Type *I8XX = PointerType::getUnqual(I8X);
-    std::vector<Type *> Params;
+    const Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
+    const Type *I8XX = PointerType::getUnqual(I8X);
+    std::vector<const Type *> Params;
     Params.push_back(I8XX);
     Params.push_back(I8X);
 
@@ -3291,8 +3291,8 @@
 Constant *ObjCARCContract::getRetainAutoreleaseCallee(Module *M) {
   if (!RetainAutoreleaseCallee) {
     LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    std::vector<Type *> Params;
+    const Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
+    std::vector<const Type *> Params;
     Params.push_back(I8X);
     const FunctionType *FTy =
       FunctionType::get(I8X, Params, /*isVarArg=*/false);
@@ -3307,8 +3307,8 @@
 Constant *ObjCARCContract::getRetainAutoreleaseRVCallee(Module *M) {
   if (!RetainAutoreleaseRVCallee) {
     LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    std::vector<Type *> Params;
+    const Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
+    std::vector<const Type *> Params;
     Params.push_back(I8X);
     const FunctionType *FTy =
       FunctionType::get(I8X, Params, /*isVarArg=*/false);
diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 66c3028..6247b03 100644
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -992,7 +992,7 @@
     }
 
     // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
-    Type *ArgType = Op->getType();
+    const Type *ArgType = Op->getType();
     Value *F = Intrinsic::getDeclaration(Callee->getParent(),
                                          Intrinsic::cttz, &ArgType, 1);
     Value *V = B.CreateCall(F, Op, "cttz");
diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp
index 6ea831f..98c9f68 100644
--- a/lib/Transforms/Utils/CloneFunction.cpp
+++ b/lib/Transforms/Utils/CloneFunction.cpp
@@ -140,7 +140,7 @@
 Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap,
                               bool ModuleLevelChanges,
                               ClonedCodeInfo *CodeInfo) {
-  std::vector<Type*> ArgTypes;
+  std::vector<const Type*> ArgTypes;
 
   // The user might be deleting arguments to the function by specifying them in
   // the VMap.  If so, we need to not add the arguments to the arg ty vector
diff --git a/lib/Transforms/Utils/CodeExtractor.cpp b/lib/Transforms/Utils/CodeExtractor.cpp
index 9a2e53f..8c133ea 100644
--- a/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/lib/Transforms/Utils/CodeExtractor.cpp
@@ -258,7 +258,7 @@
   default: RetTy = Type::getInt16Ty(header->getContext()); break;
   }
 
-  std::vector<Type*> paramTy;
+  std::vector<const Type*> paramTy;
 
   // Add the types of the input values to the function's argument list
   for (Values::const_iterator i = inputs.begin(),
@@ -279,7 +279,7 @@
   }
 
   DEBUG(dbgs() << "Function type: " << *RetTy << " f(");
-  for (std::vector<Type*>::iterator i = paramTy.begin(),
+  for (std::vector<const Type*>::iterator i = paramTy.begin(),
          e = paramTy.end(); i != e; ++i)
     DEBUG(dbgs() << **i << ", ");
   DEBUG(dbgs() << ")\n");
@@ -403,7 +403,7 @@
 
   AllocaInst *Struct = 0;
   if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
-    std::vector<Type*> ArgTypes;
+    std::vector<const Type*> ArgTypes;
     for (Values::iterator v = StructValues.begin(),
            ve = StructValues.end(); v != ve; ++v)
       ArgTypes.push_back((*v)->getType());
diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index 791d30c..348c3e4 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -663,7 +663,7 @@
   
   LLVMContext &Context = Arg->getContext();
 
-  Type *VoidPtrTy = Type::getInt8PtrTy(Context);
+  const Type *VoidPtrTy = Type::getInt8PtrTy(Context);
   
   // Create the alloca.  If we have TargetData, use nice alignment.
   unsigned Align = 1;
@@ -680,7 +680,7 @@
   Value *NewAlloca = new AllocaInst(AggTy, 0, Align, Arg->getName(), 
                                     &*Caller->begin()->begin());
   // Emit a memcpy.
-  Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
+  const Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
   Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
                                                  Intrinsic::memcpy, 
                                                  Tys, 3);
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 1529c4a..57498b4 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -619,7 +619,7 @@
 StructType *ConstantStruct::getTypeForElements(LLVMContext &Context,
                                                ArrayRef<Constant*> V,
                                                bool Packed) {
-  SmallVector<Type*, 16> EltTypes;
+  SmallVector<const Type*, 16> EltTypes;
   for (unsigned i = 0, e = V.size(); i != e; ++i)
     EltTypes.push_back(V[i]->getType());
   
diff --git a/lib/VMCore/Core.cpp b/lib/VMCore/Core.cpp
index 15d2723..d9ced94 100644
--- a/lib/VMCore/Core.cpp
+++ b/lib/VMCore/Core.cpp
@@ -260,7 +260,7 @@
 LLVMTypeRef LLVMFunctionType(LLVMTypeRef ReturnType,
                              LLVMTypeRef *ParamTypes, unsigned ParamCount,
                              LLVMBool IsVarArg) {
-  std::vector<Type*> Tys;
+  std::vector<const Type*> Tys;
   for (LLVMTypeRef *I = ParamTypes, *E = ParamTypes + ParamCount; I != E; ++I)
     Tys.push_back(unwrap(*I));
   
@@ -290,7 +290,7 @@
 
 LLVMTypeRef LLVMStructTypeInContext(LLVMContextRef C, LLVMTypeRef *ElementTypes,
                            unsigned ElementCount, LLVMBool Packed) {
-  std::vector<Type*> Tys;
+  std::vector<const Type*> Tys;
   for (LLVMTypeRef *I = ElementTypes,
                    *E = ElementTypes + ElementCount; I != E; ++I)
     Tys.push_back(unwrap(*I));
diff --git a/lib/VMCore/Function.cpp b/lib/VMCore/Function.cpp
index bde6a6d..972319e 100644
--- a/lib/VMCore/Function.cpp
+++ b/lib/VMCore/Function.cpp
@@ -333,7 +333,7 @@
   return 0;
 }
 
-std::string Intrinsic::getName(ID id, Type **Tys, unsigned numTys) { 
+std::string Intrinsic::getName(ID id, const Type **Tys, unsigned numTys) { 
   assert(id < num_intrinsics && "Invalid intrinsic ID!");
   static const char * const Table[] = {
     "not_intrinsic",
@@ -356,10 +356,10 @@
 }
 
 const FunctionType *Intrinsic::getType(LLVMContext &Context,
-                                       ID id, Type **Tys, 
+                                       ID id, const Type **Tys, 
                                        unsigned numTys) {
   const Type *ResultTy = NULL;
-  std::vector<Type*> ArgTys;
+  std::vector<const Type*> ArgTys;
   bool IsVarArg = false;
   
 #define GET_INTRINSIC_GENERATOR
@@ -384,7 +384,7 @@
 #include "llvm/Intrinsics.gen"
 #undef GET_INTRINSIC_ATTRIBUTES
 
-Function *Intrinsic::getDeclaration(Module *M, ID id, Type **Tys, 
+Function *Intrinsic::getDeclaration(Module *M, ID id, const Type **Tys, 
                                     unsigned numTys) {
   // There can never be multiple globals with the same name of different types,
   // because intrinsics must be a specific type.
diff --git a/lib/VMCore/IRBuilder.cpp b/lib/VMCore/IRBuilder.cpp
index 0908470..f2d469a 100644
--- a/lib/VMCore/IRBuilder.cpp
+++ b/lib/VMCore/IRBuilder.cpp
@@ -65,7 +65,7 @@
              bool isVolatile, MDNode *TBAATag) {
   Ptr = getCastedInt8PtrValue(Ptr);
   Value *Ops[] = { Ptr, Val, Size, getInt32(Align), getInt1(isVolatile) };
-  Type *Tys[] = { Ptr->getType(), Size->getType() };
+  const Type *Tys[] = { Ptr->getType(), Size->getType() };
   Module *M = BB->getParent()->getParent();
   Value *TheFn = Intrinsic::getDeclaration(M, Intrinsic::memset, Tys, 2);
   
@@ -85,7 +85,7 @@
   Src = getCastedInt8PtrValue(Src);
 
   Value *Ops[] = { Dst, Src, Size, getInt32(Align), getInt1(isVolatile) };
-  Type *Tys[] = { Dst->getType(), Src->getType(), Size->getType() };
+  const Type *Tys[] = { Dst->getType(), Src->getType(), Size->getType() };
   Module *M = BB->getParent()->getParent();
   Value *TheFn = Intrinsic::getDeclaration(M, Intrinsic::memcpy, Tys, 3);
   
@@ -105,7 +105,7 @@
   Src = getCastedInt8PtrValue(Src);
   
   Value *Ops[] = { Dst, Src, Size, getInt32(Align), getInt1(isVolatile) };
-  Type *Tys[] = { Dst->getType(), Src->getType(), Size->getType() };
+  const Type *Tys[] = { Dst->getType(), Src->getType(), Size->getType() };
   Module *M = BB->getParent()->getParent();
   Value *TheFn = Intrinsic::getDeclaration(M, Intrinsic::memmove, Tys, 3);
   
diff --git a/lib/VMCore/Module.cpp b/lib/VMCore/Module.cpp
index 8a738cb..1ca7016 100644
--- a/lib/VMCore/Module.cpp
+++ b/lib/VMCore/Module.cpp
@@ -216,8 +216,8 @@
   va_start(Args, RetTy);
 
   // Build the list of argument types...
-  std::vector<Type*> ArgTys;
-  while (Type *ArgTy = va_arg(Args, Type*))
+  std::vector<const Type*> ArgTys;
+  while (const Type *ArgTy = va_arg(Args, const Type*))
     ArgTys.push_back(ArgTy);
 
   va_end(Args);
@@ -234,8 +234,8 @@
   va_start(Args, RetTy);
 
   // Build the list of argument types...
-  std::vector<Type*> ArgTys;
-  while (Type *ArgTy = va_arg(Args, Type*))
+  std::vector<const Type*> ArgTys;
+  while (const Type *ArgTy = va_arg(Args, const Type*))
     ArgTys.push_back(ArgTy);
 
   va_end(Args);
diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index 10467a8..ac8b76f 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -325,6 +325,13 @@
   NumContainedTys = Params.size() + 1; // + 1 for result type
 }
 
+// FIXME: Remove this version.
+FunctionType *FunctionType::get(const Type *ReturnType,
+                                ArrayRef<const Type*> Params, bool isVarArg) {
+  return get(ReturnType, ArrayRef<Type*>(const_cast<Type**>(Params.data()),
+                                         Params.size()), isVarArg);
+}
+
 // FunctionType::get - The factory function for the FunctionType class.
 FunctionType *FunctionType::get(const Type *ReturnType,
                                 ArrayRef<Type*> Params, bool isVarArg) {
@@ -350,7 +357,7 @@
 
 
 FunctionType *FunctionType::get(const Type *Result, bool isVarArg) {
-  return get(Result, ArrayRef<Type *>(), isVarArg);
+  return get(Result, ArrayRef<const Type *>(), isVarArg);
 }
 
 
@@ -458,15 +465,22 @@
 //===----------------------------------------------------------------------===//
 // StructType Helper functions.
 
-StructType *StructType::get(LLVMContext &Context, bool isPacked) {
-  return get(Context, llvm::ArrayRef<Type*>(), isPacked);
+// FIXME: Remove this version.
+StructType *StructType::get(LLVMContext &Context, ArrayRef<const Type*>Elements,
+                            bool isPacked) {
+  return get(Context, ArrayRef<Type*>(const_cast<Type**>(Elements.data()),
+             Elements.size()), isPacked);
 }
 
-StructType *StructType::get(Type *type, ...) {
+StructType *StructType::get(LLVMContext &Context, bool isPacked) {
+  return get(Context, llvm::ArrayRef<const Type*>(), isPacked);
+}
+
+StructType *StructType::get(const Type *type, ...) {
   assert(type != 0 && "Cannot create a struct type with no elements with this");
   LLVMContext &Ctx = type->getContext();
   va_list ap;
-  SmallVector<llvm::Type*, 8> StructFields;
+  SmallVector<const llvm::Type*, 8> StructFields;
   va_start(ap, type);
   while (type) {
     StructFields.push_back(type);
diff --git a/tools/bugpoint/ExtractFunction.cpp b/tools/bugpoint/ExtractFunction.cpp
index 9941add..7ed1524 100644
--- a/tools/bugpoint/ExtractFunction.cpp
+++ b/tools/bugpoint/ExtractFunction.cpp
@@ -173,7 +173,7 @@
 static Constant *GetTorInit(std::vector<std::pair<Function*, int> > &TorList) {
   assert(!TorList.empty() && "Don't create empty tor list!");
   std::vector<Constant*> ArrayElts;
-  Type *Int32Ty = Type::getInt32Ty(TorList[0].first->getContext());
+  const Type *Int32Ty = Type::getInt32Ty(TorList[0].first->getContext());
   
   const StructType *STy =
     StructType::get(Int32Ty, TorList[0].first->getType(), NULL);
diff --git a/unittests/Analysis/ScalarEvolutionTest.cpp b/unittests/Analysis/ScalarEvolutionTest.cpp
index 39ced2a..b734160 100644
--- a/unittests/Analysis/ScalarEvolutionTest.cpp
+++ b/unittests/Analysis/ScalarEvolutionTest.cpp
@@ -23,7 +23,7 @@
   Module M("world", Context);
 
   const FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context),
-                                              std::vector<Type *>(), false);
+                                              std::vector<const Type *>(), false);
   Function *F = cast<Function>(M.getOrInsertFunction("f", FTy));
   BasicBlock *BB = BasicBlock::Create(Context, "entry", F);
   ReturnInst::Create(Context, 0, BB);
diff --git a/unittests/ExecutionEngine/JIT/JITMemoryManagerTest.cpp b/unittests/ExecutionEngine/JIT/JITMemoryManagerTest.cpp
index 039b5e0..0bc1966 100644
--- a/unittests/ExecutionEngine/JIT/JITMemoryManagerTest.cpp
+++ b/unittests/ExecutionEngine/JIT/JITMemoryManagerTest.cpp
@@ -21,7 +21,7 @@
 namespace {
 
 Function *makeFakeFunction() {
-  std::vector<Type*> params;
+  std::vector<const Type*> params;
   const FunctionType *FTy =
       FunctionType::get(Type::getVoidTy(getGlobalContext()), params, false);
   return Function::Create(FTy, GlobalValue::ExternalLinkage);
diff --git a/unittests/ExecutionEngine/JIT/JITTest.cpp b/unittests/ExecutionEngine/JIT/JITTest.cpp
index 9c001c4..ceacbbe 100644
--- a/unittests/ExecutionEngine/JIT/JITTest.cpp
+++ b/unittests/ExecutionEngine/JIT/JITTest.cpp
@@ -37,7 +37,7 @@
 namespace {
 
 Function *makeReturnGlobal(std::string Name, GlobalVariable *G, Module *M) {
-  std::vector<Type*> params;
+  std::vector<const Type*> params;
   const FunctionType *FTy = FunctionType::get(G->getType()->getElementType(),
                                               params, false);
   Function *F = Function::Create(FTy, GlobalValue::ExternalLinkage, Name, M);
@@ -322,7 +322,7 @@
 
   const FunctionType *Func1Ty =
       cast<FunctionType>(TypeBuilder<void(void), false>::get(Context));
-  std::vector<Type*> arg_types;
+  std::vector<const Type*> arg_types;
   arg_types.push_back(Type::getInt1Ty(Context));
   const FunctionType *FuncTy = FunctionType::get(
       Type::getVoidTy(Context), arg_types, false);
diff --git a/unittests/Support/TypeBuilderTest.cpp b/unittests/Support/TypeBuilderTest.cpp
index 0609178..bd19c65 100644
--- a/unittests/Support/TypeBuilderTest.cpp
+++ b/unittests/Support/TypeBuilderTest.cpp
@@ -120,7 +120,7 @@
 }
 
 TEST(TypeBuilderTest, Functions) {
-  std::vector<Type*> params;
+  std::vector<const Type*> params;
   EXPECT_EQ(FunctionType::get(Type::getVoidTy(getGlobalContext()), params, false),
             (TypeBuilder<void(), true>::get(getGlobalContext())));
   EXPECT_EQ(FunctionType::get(Type::getInt8Ty(getGlobalContext()), params, true),
@@ -187,7 +187,7 @@
   static const StructType *get(LLVMContext &Context) {
     // Using the static result variable ensures that the type is
     // only looked up once.
-    std::vector<Type*> st;
+    std::vector<const Type*> st;
     st.push_back(TypeBuilder<int, cross>::get(Context));
     st.push_back(TypeBuilder<int*, cross>::get(Context));
     st.push_back(TypeBuilder<void*[], cross>::get(Context));
@@ -210,7 +210,7 @@
   static const StructType *get(LLVMContext &Context) {
     // Using the static result variable ensures that the type is
     // only looked up once.
-    std::vector<Type*> st;
+    std::vector<const Type*> st;
     st.push_back(TypeBuilder<types::i<32>, cross>::get(Context));
     st.push_back(TypeBuilder<types::i<32>*, cross>::get(Context));
     st.push_back(TypeBuilder<types::i<8>*[], cross>::get(Context));
diff --git a/unittests/VMCore/PassManagerTest.cpp b/unittests/VMCore/PassManagerTest.cpp
index af845b0..2f2a200 100644
--- a/unittests/VMCore/PassManagerTest.cpp
+++ b/unittests/VMCore/PassManagerTest.cpp
@@ -405,13 +405,13 @@
       mod->setTargetTriple("x86_64-unknown-linux-gnu");
 
       // Type Definitions
-      std::vector<Type*>FuncTy_0_args;
+      std::vector<const Type*>FuncTy_0_args;
       FunctionType* FuncTy_0 = FunctionType::get(
         /*Result=*/IntegerType::get(getGlobalContext(), 32),
         /*Params=*/FuncTy_0_args,
         /*isVarArg=*/false);
 
-      std::vector<Type*>FuncTy_2_args;
+      std::vector<const Type*>FuncTy_2_args;
       FuncTy_2_args.push_back(IntegerType::get(getGlobalContext(), 1));
       FunctionType* FuncTy_2 = FunctionType::get(
         /*Result=*/Type::getVoidTy(getGlobalContext()),