diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
index d12d054..d4878a9 100644
--- a/include/clang/AST/ASTContext.h
+++ b/include/clang/AST/ASTContext.h
@@ -993,8 +993,7 @@
   }
 
   /// \brief Return a normal function type with a typed argument list.
-  QualType getFunctionType(QualType ResultTy,
-                           const QualType *Args, unsigned NumArgs,
+  QualType getFunctionType(QualType ResultTy, ArrayRef<QualType> Args,
                            const FunctionProtoType::ExtProtoInfo &EPI) const;
 
   /// \brief Return the unique reference to the type for the specified type
diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index f9fc90d..10143a6 100644
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -2797,7 +2797,7 @@
     return false;
   }
 
-  FunctionProtoType(QualType result, const QualType *args, unsigned numArgs,
+  FunctionProtoType(QualType result, ArrayRef<QualType> args,
                     QualType canonical, const ExtProtoInfo &epi);
 
   /// NumArgs - The number of arguments this function has, not counting '...'.
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 397bd14..b0d3ad8 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -944,12 +944,43 @@
                           SourceRange Brackets, DeclarationName Entity);
   QualType BuildExtVectorType(QualType T, Expr *ArraySize,
                               SourceLocation AttrLoc);
+
+  /// \brief Build a function type.
+  ///
+  /// This routine checks the function type according to C++ rules and
+  /// under the assumption that the result type and parameter types have
+  /// just been instantiated from a template. It therefore duplicates
+  /// some of the behavior of GetTypeForDeclarator, but in a much
+  /// simpler form that is only suitable for this narrow use case.
+  ///
+  /// \param T The return type of the function.
+  ///
+  /// \param ParamTypes The parameter types of the function. This array
+  /// will be modified to account for adjustments to the types of the
+  /// function parameters.
+  ///
+  /// \param Variadic Whether this is a variadic function type.
+  ///
+  /// \param HasTrailingReturn Whether this function has a trailing return type.
+  ///
+  /// \param Quals The cvr-qualifiers to be applied to the function type.
+  ///
+  /// \param Loc The location of the entity whose type involves this
+  /// function type or, if there is no such entity, the location of the
+  /// type that will have function type.
+  ///
+  /// \param Entity The name of the entity that involves the function
+  /// type, if known.
+  ///
+  /// \returns A suitable function type, if there are no errors.
+  /// Otherwise, returns a NULL type.
   QualType BuildFunctionType(QualType T,
-                             QualType *ParamTypes, unsigned NumParamTypes,
+                             llvm::MutableArrayRef<QualType> ParamTypes,
                              bool Variadic, bool HasTrailingReturn,
                              unsigned Quals, RefQualifierKind RefQualifier,
                              SourceLocation Loc, DeclarationName Entity,
                              FunctionType::ExtInfo Info);
+
   QualType BuildMemberPointerType(QualType T, QualType Class,
                                   SourceLocation Loc,
                                   DeclarationName Entity);
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 4580424..0b0da40 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -1974,8 +1974,10 @@
     const FunctionProtoType *FPT = cast<FunctionProtoType>(T);
     FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
     EPI.ExtInfo = Info;
-    Result = getFunctionType(FPT->getResultType(), FPT->arg_type_begin(),
-                             FPT->getNumArgs(), EPI);
+    Result = getFunctionType(FPT->getResultType(),
+                             ArrayRef<QualType>(FPT->arg_type_begin(),
+                                                FPT->getNumArgs()),
+                             EPI);
   }
 
   return cast<FunctionType>(Result.getTypePtr());
@@ -2640,13 +2642,15 @@
 /// getFunctionType - Return a normal function type with a typed argument
 /// list.  isVariadic indicates whether the argument list includes '...'.
 QualType
-ASTContext::getFunctionType(QualType ResultTy,
-                            const QualType *ArgArray, unsigned NumArgs,
+ASTContext::getFunctionType(QualType ResultTy, ArrayRef<QualType> ArgArray,
                             const FunctionProtoType::ExtProtoInfo &EPI) const {
+  size_t NumArgs = ArgArray.size();
+
   // Unique functions, to guarantee there is only one function of a particular
   // structure.
   llvm::FoldingSetNodeID ID;
-  FunctionProtoType::Profile(ID, ResultTy, ArgArray, NumArgs, EPI, *this);
+  FunctionProtoType::Profile(ID, ResultTy, ArgArray.begin(), NumArgs, EPI,
+                             *this);
 
   void *InsertPos = 0;
   if (FunctionProtoType *FTP =
@@ -2689,9 +2693,7 @@
       CanResultTy = getQualifiedType(CanResultTy.getUnqualifiedType(), Qs);
     }
 
-    Canonical = getFunctionType(CanResultTy,
-                                CanonicalArgs.data(), NumArgs,
-                                CanonicalEPI);
+    Canonical = getFunctionType(CanResultTy, CanonicalArgs, CanonicalEPI);
 
     // Get the new insert position for the node we care about.
     FunctionProtoType *NewIP =
@@ -2724,7 +2726,7 @@
   FunctionProtoType *FTP = (FunctionProtoType*) Allocate(Size, TypeAlignment);
   FunctionProtoType::ExtProtoInfo newEPI = EPI;
   newEPI.ExtInfo = EPI.ExtInfo.withCallingConv(CallConv);
-  new (FTP) FunctionProtoType(ResultTy, ArgArray, NumArgs, Canonical, newEPI);
+  new (FTP) FunctionProtoType(ResultTy, ArgArray, Canonical, newEPI);
   Types.push_back(FTP);
   FunctionProtoTypes.InsertNode(FTP, InsertPos);
   return QualType(FTP, 0);
@@ -6794,7 +6796,7 @@
 
     FunctionProtoType::ExtProtoInfo EPI = lproto->getExtProtoInfo();
     EPI.ExtInfo = einfo;
-    return getFunctionType(retType, types.begin(), types.size(), EPI);
+    return getFunctionType(retType, types, EPI);
   }
 
   if (lproto) allRTypes = false;
@@ -6831,8 +6833,10 @@
 
     FunctionProtoType::ExtProtoInfo EPI = proto->getExtProtoInfo();
     EPI.ExtInfo = einfo;
-    return getFunctionType(retType, proto->arg_type_begin(),
-                           proto->getNumArgs(), EPI);
+    return getFunctionType(retType,
+                           ArrayRef<QualType>(proto->arg_type_begin(),
+                                              proto->getNumArgs()),
+                           EPI);
   }
 
   if (allLTypes) return lhs;
@@ -7165,8 +7169,10 @@
         FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
         EPI.ExtInfo = getFunctionExtInfo(LHS);
         QualType ResultType
-          = getFunctionType(OldReturnType, FPT->arg_type_begin(),
-                            FPT->getNumArgs(), EPI);
+          = getFunctionType(OldReturnType,
+                            ArrayRef<QualType>(FPT->arg_type_begin(),
+                                               FPT->getNumArgs()),
+                            EPI);
         return ResultType;
       }
     }
@@ -7558,7 +7564,7 @@
   EPI.ExtInfo = EI;
   EPI.Variadic = Variadic;
 
-  return getFunctionType(ResType, ArgTypes.data(), ArgTypes.size(), EPI);
+  return getFunctionType(ResType, ArgTypes, EPI);
 }
 
 GVALinkage ASTContext::GetGVALinkageForFunction(const FunctionDecl *FD) {
diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index bdf2bbc..01d1a1e 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -1619,8 +1619,7 @@
   ToEPI.ExceptionSpecTemplate = cast_or_null<FunctionDecl>(
                                 Importer.Import(FromEPI.ExceptionSpecTemplate));
 
-  return Importer.getToContext().getFunctionType(ToResultType, ArgTypes.data(),
-                                                 ArgTypes.size(), ToEPI);
+  return Importer.getToContext().getFunctionType(ToResultType, ArgTypes, ToEPI);
 }
 
 QualType ASTNodeImporter::VisitParenType(const ParenType *T) {
@@ -2660,8 +2659,8 @@
       FunctionProtoType::ExtProtoInfo DefaultEPI;
       FromTy = Importer.getFromContext().getFunctionType(
                             FromFPT->getResultType(),
-                            FromFPT->arg_type_begin(),
-                            FromFPT->arg_type_end() - FromFPT->arg_type_begin(),
+                            ArrayRef<QualType>(FromFPT->arg_type_begin(),
+                                               FromFPT->getNumArgs()),
                             DefaultEPI);
       usedDifferentExceptionSpec = true;
     }
diff --git a/lib/AST/ExprCXX.cpp b/lib/AST/ExprCXX.cpp
index e1e96e4..12a47fc 100644
--- a/lib/AST/ExprCXX.cpp
+++ b/lib/AST/ExprCXX.cpp
@@ -178,7 +178,8 @@
                 SourceLocation ColonColonLoc, SourceLocation TildeLoc, 
                 PseudoDestructorTypeStorage DestroyedType)
   : Expr(CXXPseudoDestructorExprClass,
-         Context.getPointerType(Context.getFunctionType(Context.VoidTy, 0, 0,
+         Context.getPointerType(Context.getFunctionType(Context.VoidTy,
+                                                        ArrayRef<QualType>(),
                                          FunctionProtoType::ExtProtoInfo())),
          VK_RValue, OK_Ordinary,
          /*isTypeDependent=*/(Base->isTypeDependent() ||
diff --git a/lib/AST/LambdaMangleContext.cpp b/lib/AST/LambdaMangleContext.cpp
index 6f4fe2d..54f445d 100644
--- a/lib/AST/LambdaMangleContext.cpp
+++ b/lib/AST/LambdaMangleContext.cpp
@@ -23,10 +23,11 @@
     = CallOperator->getType()->getAs<FunctionProtoType>();
   ASTContext &Context = CallOperator->getASTContext();
   
-  QualType Key = Context.getFunctionType(Context.VoidTy, 
-                                         Proto->arg_type_begin(),
-                                         Proto->getNumArgs(),
-                                         FunctionProtoType::ExtProtoInfo());
+  QualType Key =
+    Context.getFunctionType(Context.VoidTy,
+                            ArrayRef<QualType>(Proto->arg_type_begin(),
+                                               Proto->getNumArgs()),
+                            FunctionProtoType::ExtProtoInfo());
   Key = Context.getCanonicalType(Key);
   return ++ManglingNumbers[Key->castAs<FunctionProtoType>()];
 }
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index e6687a7..f6fcab5 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -1560,8 +1560,8 @@
   llvm_unreachable("Invalid calling convention.");
 }
 
-FunctionProtoType::FunctionProtoType(QualType result, const QualType *args,
-                                     unsigned numArgs, QualType canonical,
+FunctionProtoType::FunctionProtoType(QualType result, ArrayRef<QualType> args,
+                                     QualType canonical,
                                      const ExtProtoInfo &epi)
   : FunctionType(FunctionProto, result, epi.TypeQuals,
                  canonical,
@@ -1570,17 +1570,17 @@
                  result->isVariablyModifiedType(),
                  result->containsUnexpandedParameterPack(),
                  epi.ExtInfo),
-    NumArgs(numArgs), NumExceptions(epi.NumExceptions),
+    NumArgs(args.size()), NumExceptions(epi.NumExceptions),
     ExceptionSpecType(epi.ExceptionSpecType),
     HasAnyConsumedArgs(epi.ConsumedArguments != 0),
     Variadic(epi.Variadic), HasTrailingReturn(epi.HasTrailingReturn),
     RefQualifier(epi.RefQualifier)
 {
-  assert(NumArgs == numArgs && "function has too many parameters");
+  assert(NumArgs == args.size() && "function has too many parameters");
 
   // Fill in the trailing argument array.
   QualType *argSlot = reinterpret_cast<QualType*>(this+1);
-  for (unsigned i = 0; i != numArgs; ++i) {
+  for (unsigned i = 0; i != NumArgs; ++i) {
     if (args[i]->isDependentType())
       setDependent();
     else if (args[i]->isInstantiationDependentType())
@@ -1594,7 +1594,7 @@
 
   if (getExceptionSpecType() == EST_Dynamic) {
     // Fill in the exception array.
-    QualType *exnSlot = argSlot + numArgs;
+    QualType *exnSlot = argSlot + NumArgs;
     for (unsigned i = 0, e = epi.NumExceptions; i != e; ++i) {
       if (epi.Exceptions[i]->isDependentType())
         setDependent();
@@ -1608,7 +1608,7 @@
     }
   } else if (getExceptionSpecType() == EST_ComputedNoexcept) {
     // Store the noexcept expression and context.
-    Expr **noexSlot = reinterpret_cast<Expr**>(argSlot + numArgs);
+    Expr **noexSlot = reinterpret_cast<Expr**>(argSlot + NumArgs);
     *noexSlot = epi.NoexceptExpr;
     
     if (epi.NoexceptExpr) {
@@ -1621,7 +1621,7 @@
   } else if (getExceptionSpecType() == EST_Uninstantiated) {
     // Store the function decl from which we will resolve our
     // exception specification.
-    FunctionDecl **slot = reinterpret_cast<FunctionDecl**>(argSlot + numArgs);
+    FunctionDecl **slot = reinterpret_cast<FunctionDecl**>(argSlot + NumArgs);
     slot[0] = epi.ExceptionSpecDecl;
     slot[1] = epi.ExceptionSpecTemplate;
     // This exception specification doesn't make the type dependent, because
@@ -1629,13 +1629,13 @@
   } else if (getExceptionSpecType() == EST_Unevaluated) {
     // Store the function decl from which we will resolve our
     // exception specification.
-    FunctionDecl **slot = reinterpret_cast<FunctionDecl**>(argSlot + numArgs);
+    FunctionDecl **slot = reinterpret_cast<FunctionDecl**>(argSlot + NumArgs);
     slot[0] = epi.ExceptionSpecDecl;
   }
 
   if (epi.ConsumedArguments) {
     bool *consumedArgs = const_cast<bool*>(getConsumedArgsBuffer());
-    for (unsigned i = 0; i != numArgs; ++i)
+    for (unsigned i = 0; i != NumArgs; ++i)
       consumedArgs[i] = epi.ConsumedArguments[i];
   }
 }
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index bd4c98e..27ef65f 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -420,19 +420,16 @@
 
   // Emit subprogram debug descriptor.
   if (CGDebugInfo *DI = getDebugInfo()) {
-    unsigned NumArgs = 0;
-    QualType *ArgsArray = new QualType[Args.size()];
+    SmallVector<QualType, 16> ArgTypes;
     for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
 	 i != e; ++i) {
-      ArgsArray[NumArgs++] = (*i)->getType();
+      ArgTypes.push_back((*i)->getType());
     }
 
     QualType FnType =
-      getContext().getFunctionType(RetTy, ArgsArray, NumArgs,
+      getContext().getFunctionType(RetTy, ArgTypes,
                                    FunctionProtoType::ExtProtoInfo());
 
-    delete[] ArgsArray;
-
     DI->setLocation(StartLoc);
     DI->EmitFunctionStart(GD, FnType, CurFn, Builder);
   }
diff --git a/lib/Rewrite/Frontend/RewriteModernObjC.cpp b/lib/Rewrite/Frontend/RewriteModernObjC.cpp
index f688603..caba62b 100644
--- a/lib/Rewrite/Frontend/RewriteModernObjC.cpp
+++ b/lib/Rewrite/Frontend/RewriteModernObjC.cpp
@@ -572,14 +572,13 @@
     }
 
     QualType getSimpleFunctionType(QualType result,
-                                   const QualType *args,
-                                   unsigned numArgs,
+                                   ArrayRef<QualType> args,
                                    bool variadic = false) {
       if (result == Context->getObjCInstanceType())
         result =  Context->getObjCIdType();
       FunctionProtoType::ExtProtoInfo fpi;
       fpi.Variadic = variadic;
-      return Context->getFunctionType(result, args, numArgs, fpi);
+      return Context->getFunctionType(result, args, fpi);
     }
 
     // Helper function: create a CStyleCastExpr with trivial type source info.
@@ -2358,7 +2357,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
   QualType getFuncType =
-    getSimpleFunctionType(Context->getObjCSelType(), &ArgTys[0], ArgTys.size());
+    getSimpleFunctionType(Context->getObjCSelType(), ArgTys);
   SelGetUidFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                SourceLocation(),
                                                SourceLocation(),
@@ -2456,7 +2455,7 @@
   ArgTys.push_back(argT);
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size());
+                                               ArgTys);
   SuperContructorFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                      SourceLocation(),
                                                      SourceLocation(),
@@ -2475,8 +2474,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                              SourceLocation(),
                                              SourceLocation(),
@@ -2490,8 +2488,7 @@
   SmallVector<QualType, 2> ArgTys;
   ArgTys.push_back(Context->VoidTy);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], 1,
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendSuperFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2510,8 +2507,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2527,8 +2523,7 @@
   SmallVector<QualType, 2> ArgTys;
   ArgTys.push_back(Context->VoidTy);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], 1,
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendSuperStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                        SourceLocation(),
                                                        SourceLocation(),
@@ -2548,8 +2543,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->DoubleTy,
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendFpretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2563,7 +2557,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
   QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
-                                                &ArgTys[0], ArgTys.size());
+                                                ArgTys);
   GetClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                               SourceLocation(),
                                               SourceLocation(),
@@ -2578,7 +2572,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getObjCClassType());
   QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
-                                                &ArgTys[0], ArgTys.size());
+                                                ArgTys);
   GetSuperClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                    SourceLocation(),
                                                    SourceLocation(),
@@ -2593,7 +2587,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
   QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
-                                                &ArgTys[0], ArgTys.size());
+                                                ArgTys);
   GetMetaClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2740,8 +2734,7 @@
   
   // Now do the "normal" pointer to function cast.
   QualType castType =
-  getSimpleFunctionType(returnType, &ArgTypes[0], ArgTypes.size(),
-                        BoxingMethod->isVariadic());
+    getSimpleFunctionType(returnType, ArgTypes, BoxingMethod->isVariadic());
   castType = Context->getPointerType(castType);
   cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
                                   cast);
@@ -2774,7 +2767,7 @@
   // Build the expression: __NSContainer_literal(int, ...).arr
   QualType IntQT = Context->IntTy;
   QualType NSArrayFType =
-    getSimpleFunctionType(Context->VoidTy, &IntQT, 1, true);
+    getSimpleFunctionType(Context->VoidTy, IntQT, true);
   std::string NSArrayFName("__NSContainer_literal");
   FunctionDecl *NSArrayFD = SynthBlockInitFunctionDecl(NSArrayFName);
   DeclRefExpr *NSArrayDRE = 
@@ -2878,8 +2871,7 @@
   
   // Now do the "normal" pointer to function cast.
   QualType castType =
-  getSimpleFunctionType(returnType, &ArgTypes[0], ArgTypes.size(),
-                        ArrayMethod->isVariadic());
+  getSimpleFunctionType(returnType, ArgTypes, ArrayMethod->isVariadic());
   castType = Context->getPointerType(castType);
   cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
                                   cast);
@@ -2912,7 +2904,7 @@
   // Build the expression: __NSContainer_literal(int, ...).arr
   QualType IntQT = Context->IntTy;
   QualType NSDictFType =
-    getSimpleFunctionType(Context->VoidTy, &IntQT, 1, true);
+    getSimpleFunctionType(Context->VoidTy, IntQT, true);
   std::string NSDictFName("__NSContainer_literal");
   FunctionDecl *NSDictFD = SynthBlockInitFunctionDecl(NSDictFName);
   DeclRefExpr *NSDictDRE = 
@@ -3052,8 +3044,7 @@
   
   // Now do the "normal" pointer to function cast.
   QualType castType =
-  getSimpleFunctionType(returnType, &ArgTypes[0], ArgTypes.size(),
-                        DictMethod->isVariadic());
+  getSimpleFunctionType(returnType, ArgTypes, DictMethod->isVariadic());
   castType = Context->getPointerType(castType);
   cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
                                   cast);
@@ -3195,8 +3186,9 @@
                                                  SmallVectorImpl<Expr*> &MsgExprs,
                                                  ObjCMethodDecl *Method) {
   // Now do the "normal" pointer to function cast.
-  QualType castType = getSimpleFunctionType(returnType, &ArgTypes[0], ArgTypes.size(),
-                                            Method ? Method->isVariadic() : false);
+  QualType castType = getSimpleFunctionType(returnType, ArgTypes,
+                                            Method ? Method->isVariadic()
+                                                   : false);
   castType = Context->getPointerType(castType);
   
   // build type for containing the objc_msgSend_stret object.
@@ -3635,10 +3627,10 @@
                                   CK_BitCast, DRE);
 
   // Now do the "normal" pointer to function cast.
+  // If we don't have a method decl, force a variadic cast.
+  const ObjCMethodDecl *MD = Exp->getMethodDecl();
   QualType castType =
-    getSimpleFunctionType(returnType, &ArgTypes[0], ArgTypes.size(),
-      // If we don't have a method decl, force a variadic cast.
-      Exp->getMethodDecl() ? Exp->getMethodDecl()->isVariadic() : true);
+    getSimpleFunctionType(returnType, ArgTypes, MD ? MD->isVariadic() : true);
   castType = Context->getPointerType(castType);
   cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
                                   cast);
@@ -4744,7 +4736,7 @@
   }
   QualType FuncType;
   if (modified)
-    FuncType = getSimpleFunctionType(Res, &ArgTypes[0], ArgTypes.size());
+    FuncType = getSimpleFunctionType(Res, ArgTypes);
   else FuncType = QualType(FT, 0);
   return FuncType;
 }
@@ -4811,8 +4803,7 @@
     }
   }
   // Now do the pointer to function cast.
-  QualType PtrToFuncCastType
-    = getSimpleFunctionType(Exp->getType(), &ArgTypes[0], ArgTypes.size());
+  QualType PtrToFuncCastType = getSimpleFunctionType(Exp->getType(), ArgTypes);
 
   PtrToFuncCastType = Context->getPointerType(PtrToFuncCastType);
 
diff --git a/lib/Rewrite/Frontend/RewriteObjC.cpp b/lib/Rewrite/Frontend/RewriteObjC.cpp
index b5d9f0c..1080417 100644
--- a/lib/Rewrite/Frontend/RewriteObjC.cpp
+++ b/lib/Rewrite/Frontend/RewriteObjC.cpp
@@ -485,14 +485,13 @@
     }
 
     QualType getSimpleFunctionType(QualType result,
-                                   const QualType *args,
-                                   unsigned numArgs,
+                                   ArrayRef<QualType> args,
                                    bool variadic = false) {
       if (result == Context->getObjCInstanceType())
         result =  Context->getObjCIdType();
       FunctionProtoType::ExtProtoInfo fpi;
       fpi.Variadic = variadic;
-      return Context->getFunctionType(result, args, numArgs, fpi);
+      return Context->getFunctionType(result, args, fpi);
     }
 
     // Helper function: create a CStyleCastExpr with trivial type source info.
@@ -2263,7 +2262,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
   QualType getFuncType =
-    getSimpleFunctionType(Context->getObjCSelType(), &ArgTys[0], ArgTys.size());
+    getSimpleFunctionType(Context->getObjCSelType(), ArgTys);
   SelGetUidFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                SourceLocation(),
                                                SourceLocation(),
@@ -2359,7 +2358,7 @@
   ArgTys.push_back(argT);
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size());
+                                               ArgTys);
   SuperContructorFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                      SourceLocation(),
                                                      SourceLocation(),
@@ -2378,8 +2377,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                              SourceLocation(),
                                              SourceLocation(),
@@ -2401,8 +2399,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendSuperFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2421,8 +2418,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2446,8 +2442,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendSuperStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                        SourceLocation(),
                                                        SourceLocation(),
@@ -2467,8 +2462,7 @@
   assert(!argT.isNull() && "Can't find 'SEL' type");
   ArgTys.push_back(argT);
   QualType msgSendType = getSimpleFunctionType(Context->DoubleTy,
-                                               &ArgTys[0], ArgTys.size(),
-                                               true /*isVariadic*/);
+                                               ArgTys, /*isVariadic=*/true);
   MsgSendFpretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2482,7 +2476,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
   QualType getClassType = getSimpleFunctionType(Context->getObjCIdType(),
-                                                &ArgTys[0], ArgTys.size());
+                                                ArgTys);
   GetClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                               SourceLocation(),
                                               SourceLocation(),
@@ -2497,7 +2491,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getObjCClassType());
   QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
-                                                &ArgTys[0], ArgTys.size());
+                                                ArgTys);
   GetSuperClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                    SourceLocation(),
                                                    SourceLocation(),
@@ -2512,7 +2506,7 @@
   SmallVector<QualType, 16> ArgTys;
   ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
   QualType getClassType = getSimpleFunctionType(Context->getObjCIdType(),
-                                                &ArgTys[0], ArgTys.size());
+                                                ArgTys);
   GetMetaClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
                                                   SourceLocation(),
                                                   SourceLocation(),
@@ -2642,8 +2636,9 @@
                                   Context->getPointerType(Context->VoidTy),
                                   CK_BitCast, STDRE);
   // Now do the "normal" pointer to function cast.
-  QualType castType = getSimpleFunctionType(returnType, &ArgTypes[0], ArgTypes.size(),
-                                            Method ? Method->isVariadic() : false);
+  QualType castType = getSimpleFunctionType(returnType, ArgTypes,
+                                            Method ? Method->isVariadic()
+                                                   : false);
   castType = Context->getPointerType(castType);
   cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
                                             cast);
@@ -3024,10 +3019,10 @@
                                   CK_BitCast, DRE);
 
   // Now do the "normal" pointer to function cast.
+  // If we don't have a method decl, force a variadic cast.
+  const ObjCMethodDecl *MD = Exp->getMethodDecl();
   QualType castType =
-    getSimpleFunctionType(returnType, &ArgTypes[0], ArgTypes.size(),
-      // If we don't have a method decl, force a variadic cast.
-      Exp->getMethodDecl() ? Exp->getMethodDecl()->isVariadic() : true);
+    getSimpleFunctionType(returnType, ArgTypes, MD ? MD->isVariadic() : true);
   castType = Context->getPointerType(castType);
   cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
                                   cast);
@@ -3806,7 +3801,7 @@
   // FIXME. Does this work if block takes no argument but has a return type
   // which is of block type?
   if (HasBlockType)
-    FuncType = getSimpleFunctionType(Res, &ArgTypes[0], ArgTypes.size());
+    FuncType = getSimpleFunctionType(Res, ArgTypes);
   else FuncType = QualType(FT, 0);
   return FuncType;
 }
@@ -3873,8 +3868,7 @@
     }
   }
   // Now do the pointer to function cast.
-  QualType PtrToFuncCastType
-    = getSimpleFunctionType(Exp->getType(), &ArgTypes[0], ArgTypes.size());
+  QualType PtrToFuncCastType = getSimpleFunctionType(Exp->getType(), ArgTypes);
 
   PtrToFuncCastType = Context->getPointerType(PtrToFuncCastType);
 
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 00d1cf1..35af7b7 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2563,7 +2563,7 @@
       SmallVector<QualType, 16> ParamTypes(OldProto->arg_type_begin(),
                                                  OldProto->arg_type_end());
       NewQType = Context.getFunctionType(NewFuncType->getResultType(),
-                                         ParamTypes.data(), ParamTypes.size(),
+                                         ParamTypes,
                                          OldProto->getExtProtoInfo());
       New->setType(NewQType);
       New->setHasInheritedPrototype();
@@ -2646,8 +2646,7 @@
                diag::note_previous_declaration);
       }
 
-      New->setType(Context.getFunctionType(MergedReturn, &ArgTypes[0],
-                                           ArgTypes.size(),
+      New->setType(Context.getFunctionType(MergedReturn, ArgTypes,
                                            OldProto->getExtProtoInfo()));
       return MergeCompatibleFunctionDecls(New, Old, S);
     }
@@ -5701,8 +5700,10 @@
     T = Context.getObjCObjectPointerType(T);
     if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(R)) {
       FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
-      R = Context.getFunctionType(T, FPT->arg_type_begin(),
-                                  FPT->getNumArgs(), EPI);
+      R = Context.getFunctionType(T,
+                                  ArrayRef<QualType>(FPT->arg_type_begin(),
+                                                     FPT->getNumArgs()),
+                                  EPI);
     }
     else if (isa<FunctionNoProtoType>(R))
       R = Context.getFunctionNoProtoType(T);
@@ -5997,8 +5998,9 @@
       FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
       EPI.ExceptionSpecType = EST_BasicNoexcept;
       NewFD->setType(Context.getFunctionType(FPT->getResultType(),
-                                             FPT->arg_type_begin(),
-                                             FPT->getNumArgs(), EPI));
+                                      ArrayRef<QualType>(FPT->arg_type_begin(),
+                                                         FPT->getNumArgs()),
+                                             EPI));
     }
   }
 
@@ -6382,7 +6384,9 @@
     EPI.Variadic = true;
     EPI.ExtInfo = FT->getExtInfo();
 
-    QualType R = Context.getFunctionType(FT->getResultType(), 0, 0, EPI);
+    QualType R = Context.getFunctionType(FT->getResultType(),
+                                         ArrayRef<QualType>(),
+                                         EPI);
     NewFD->setType(R);
   }
 
@@ -6583,8 +6587,9 @@
       FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
       EPI.TypeQuals |= Qualifiers::Const;
       MD->setType(Context.getFunctionType(FPT->getResultType(),
-                                          FPT->arg_type_begin(),
-                                          FPT->getNumArgs(), EPI));
+                                      ArrayRef<QualType>(FPT->arg_type_begin(),
+                                                         FPT->getNumArgs()),
+                                          EPI));
     }
   }
 
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 22a31e0..f66509d 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -4194,8 +4194,10 @@
   FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
   ExceptSpec.getEPI(EPI);
   const FunctionProtoType *NewFPT = cast<FunctionProtoType>(
-    S.Context.getFunctionType(FPT->getResultType(), FPT->arg_type_begin(),
-                              FPT->getNumArgs(), EPI));
+    S.Context.getFunctionType(FPT->getResultType(),
+                              ArrayRef<QualType>(FPT->arg_type_begin(),
+                                                 FPT->getNumArgs()),
+                              EPI));
   FD->setType(QualType(NewFPT, 0));
 }
 
@@ -4357,8 +4359,10 @@
     FunctionProtoType::ExtProtoInfo EPI = Type->getExtProtoInfo();
     EPI.ExceptionSpecType = EST_Unevaluated;
     EPI.ExceptionSpecDecl = MD;
-    MD->setType(Context.getFunctionType(ReturnType, &ArgType,
-                                        ExpectedParams, EPI));
+    MD->setType(Context.getFunctionType(ReturnType,
+                                        ArrayRef<QualType>(&ArgType,
+                                                           ExpectedParams),
+                                        EPI));
   }
 
   if (ShouldDeleteSpecialMember(MD, CSM)) {
@@ -4387,7 +4391,7 @@
   FunctionProtoType::ExtProtoInfo EPI;
   computeImplicitExceptionSpec(*this, MD->getLocation(), MD).getEPI(EPI);
   const FunctionProtoType *ImplicitType = cast<FunctionProtoType>(
-    Context.getFunctionType(Context.VoidTy, 0, 0, EPI));
+    Context.getFunctionType(Context.VoidTy, ArrayRef<QualType>(), EPI));
 
   // Ensure that it matches.
   CheckEquivalentExceptionSpec(
@@ -5640,8 +5644,10 @@
   EPI.TypeQuals = 0;
   EPI.RefQualifier = RQ_None;
   
-  return Context.getFunctionType(Context.VoidTy, Proto->arg_type_begin(),
-                                 Proto->getNumArgs(), EPI);
+  return Context.getFunctionType(Context.VoidTy,
+                                 ArrayRef<QualType>(Proto->arg_type_begin(),
+                                                    Proto->getNumArgs()),
+                                 EPI);
 }
 
 /// CheckConstructor - Checks a fully-formed constructor for
@@ -5821,7 +5827,7 @@
   EPI.Variadic = false;
   EPI.TypeQuals = 0;
   EPI.RefQualifier = RQ_None;
-  return Context.getFunctionType(Context.VoidTy, 0, 0, EPI);
+  return Context.getFunctionType(Context.VoidTy, ArrayRef<QualType>(), EPI);
 }
 
 /// CheckConversionDeclarator - Called by ActOnDeclarator to check the
@@ -5902,7 +5908,8 @@
   // of the errors above fired) and with the conversion type as the
   // return type.
   if (D.isInvalidType())
-    R = Context.getFunctionType(ConvType, 0, 0, Proto->getExtProtoInfo());
+    R = Context.getFunctionType(ConvType, ArrayRef<QualType>(),
+                                Proto->getExtProtoInfo());
 
   // C++0x explicit conversion operators.
   if (D.getDeclSpec().isExplicitSpecified())
@@ -7532,7 +7539,9 @@
   FunctionProtoType::ExtProtoInfo EPI;
   EPI.ExceptionSpecType = EST_Unevaluated;
   EPI.ExceptionSpecDecl = DefaultCon;
-  DefaultCon->setType(Context.getFunctionType(Context.VoidTy, 0, 0, EPI));
+  DefaultCon->setType(Context.getFunctionType(Context.VoidTy,
+                                              ArrayRef<QualType>(),
+                                              EPI));
 
   // We don't need to use SpecialMemberIsTrivial here; triviality for default
   // constructors is easy to compute.
@@ -7697,7 +7706,7 @@
               BaseCtorType->getExtProtoInfo();
           ExtInfo.Variadic = false;
           NewCtorType = Context.getFunctionType(BaseCtorType->getResultType(),
-                                                Args.data(), params, ExtInfo)
+                                                Args, ExtInfo)
                        .getTypePtr();
         }
         const Type *CanonicalNewCtorType =
@@ -7843,7 +7852,9 @@
   FunctionProtoType::ExtProtoInfo EPI;
   EPI.ExceptionSpecType = EST_Unevaluated;
   EPI.ExceptionSpecDecl = Destructor;
-  Destructor->setType(Context.getFunctionType(Context.VoidTy, 0, 0, EPI));
+  Destructor->setType(Context.getFunctionType(Context.VoidTy,
+                                              ArrayRef<QualType>(),
+                                              EPI));
 
   AddOverriddenMethods(ClassDecl, Destructor);
 
@@ -7947,7 +7958,9 @@
   FunctionProtoType::ExtProtoInfo EPI = DtorType->getExtProtoInfo();
   EPI.ExceptionSpecType = EST_Unevaluated;
   EPI.ExceptionSpecDecl = Destructor;
-  Destructor->setType(Context.getFunctionType(Context.VoidTy, 0, 0, EPI));
+  Destructor->setType(Context.getFunctionType(Context.VoidTy,
+                                              ArrayRef<QualType>(),
+                                              EPI));
 
   // FIXME: If the destructor has a body that could throw, and the newly created
   // spec doesn't allow exceptions, we should emit a warning, because this
@@ -8347,7 +8360,7 @@
   FunctionProtoType::ExtProtoInfo EPI;
   EPI.ExceptionSpecType = EST_Unevaluated;
   EPI.ExceptionSpecDecl = CopyAssignment;
-  CopyAssignment->setType(Context.getFunctionType(RetType, &ArgType, 1, EPI));
+  CopyAssignment->setType(Context.getFunctionType(RetType, ArgType, EPI));
 
   // Add the parameter to the operator.
   ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyAssignment,
@@ -8797,7 +8810,7 @@
   FunctionProtoType::ExtProtoInfo EPI;
   EPI.ExceptionSpecType = EST_Unevaluated;
   EPI.ExceptionSpecDecl = MoveAssignment;
-  MoveAssignment->setType(Context.getFunctionType(RetType, &ArgType, 1, EPI));
+  MoveAssignment->setType(Context.getFunctionType(RetType, ArgType, EPI));
 
   // Add the parameter to the operator.
   ParmVarDecl *FromParam = ParmVarDecl::Create(Context, MoveAssignment,
@@ -9151,7 +9164,7 @@
   EPI.ExceptionSpecType = EST_Unevaluated;
   EPI.ExceptionSpecDecl = CopyConstructor;
   CopyConstructor->setType(
-      Context.getFunctionType(Context.VoidTy, &ArgType, 1, EPI));
+      Context.getFunctionType(Context.VoidTy, ArgType, EPI));
 
   // Add the parameter to the constructor.
   ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyConstructor,
@@ -9338,7 +9351,7 @@
   EPI.ExceptionSpecType = EST_Unevaluated;
   EPI.ExceptionSpecDecl = MoveConstructor;
   MoveConstructor->setType(
-      Context.getFunctionType(Context.VoidTy, &ArgType, 1, EPI));
+      Context.getFunctionType(Context.VoidTy, ArgType, EPI));
 
   // Add the parameter to the constructor.
   ParmVarDecl *FromParam = ParmVarDecl::Create(Context, MoveConstructor,
diff --git a/lib/Sema/SemaExceptionSpec.cpp b/lib/Sema/SemaExceptionSpec.cpp
index 29ce7db..ab8dcd1 100644
--- a/lib/Sema/SemaExceptionSpec.cpp
+++ b/lib/Sema/SemaExceptionSpec.cpp
@@ -203,10 +203,11 @@
       Old->isExternC()) {
     FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
     EPI.ExceptionSpecType = EST_DynamicNone;
-    QualType NewType = Context.getFunctionType(NewProto->getResultType(),
-                                               NewProto->arg_type_begin(),
-                                               NewProto->getNumArgs(),
-                                               EPI);
+    QualType NewType =
+      Context.getFunctionType(NewProto->getResultType(),
+                              ArrayRef<QualType>(NewProto->arg_type_begin(),
+                                                 NewProto->getNumArgs()),
+                              EPI);
     New->setType(NewType);
     return false;
   }
@@ -227,10 +228,11 @@
 
     // Update the type of the function with the appropriate exception
     // specification.
-    QualType NewType = Context.getFunctionType(NewProto->getResultType(),
-                                               NewProto->arg_type_begin(),
-                                               NewProto->getNumArgs(),
-                                               EPI);
+    QualType NewType =
+      Context.getFunctionType(NewProto->getResultType(),
+                              ArrayRef<QualType>(NewProto->arg_type_begin(),
+                                                 NewProto->getNumArgs()),
+                              EPI);
     New->setType(NewType);
 
     // If exceptions are disabled, suppress the warning about missing
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 840a714..69e06ea 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9485,8 +9485,7 @@
     FunctionProtoType::ExtProtoInfo EPI;
     EPI.HasTrailingReturn = false;
     EPI.TypeQuals |= DeclSpec::TQ_const;
-    T = Context.getFunctionType(Context.DependentTy, /*Args=*/0, /*NumArgs=*/0,
-                                EPI);
+    T = Context.getFunctionType(Context.DependentTy, ArrayRef<QualType>(), EPI);
     Sig = Context.getTrivialTypeSourceInfo(T);
   }
   
@@ -9665,7 +9664,7 @@
     if (isa<FunctionNoProtoType>(FTy)) {
       FunctionProtoType::ExtProtoInfo EPI;
       EPI.ExtInfo = Ext;
-      BlockTy = Context.getFunctionType(RetTy, 0, 0, EPI);
+      BlockTy = Context.getFunctionType(RetTy, ArrayRef<QualType>(), EPI);
 
     // Otherwise, if we don't need to change anything about the function type,
     // preserve its sugar structure.
@@ -9679,17 +9678,18 @@
       FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
       EPI.TypeQuals = 0; // FIXME: silently?
       EPI.ExtInfo = Ext;
-      BlockTy = Context.getFunctionType(RetTy,
-                                        FPT->arg_type_begin(),
-                                        FPT->getNumArgs(),
-                                        EPI);
+      BlockTy =
+        Context.getFunctionType(RetTy,
+                                ArrayRef<QualType>(FPT->arg_type_begin(),
+                                                   FPT->getNumArgs()),
+                                EPI);
     }
 
   // If we don't have a function type, just build one from nothing.
   } else {
     FunctionProtoType::ExtProtoInfo EPI;
     EPI.ExtInfo = FunctionType::ExtInfo().withNoReturn(NoReturn);
-    BlockTy = Context.getFunctionType(RetTy, 0, 0, EPI);
+    BlockTy = Context.getFunctionType(RetTy, ArrayRef<QualType>(), EPI);
   }
 
   DiagnoseUnusedParameters(BSI->TheDecl->param_begin(),
@@ -11845,10 +11845,11 @@
 
   // Rebuild the function type, replacing the result type with DestType.
   if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FnType))
-    DestType = S.Context.getFunctionType(DestType,
-                                         Proto->arg_type_begin(),
-                                         Proto->getNumArgs(),
-                                         Proto->getExtProtoInfo());
+    DestType =
+      S.Context.getFunctionType(DestType,
+                                ArrayRef<QualType>(Proto->arg_type_begin(),
+                                                   Proto->getNumArgs()),
+                                Proto->getExtProtoInfo());
   else
     DestType = S.Context.getFunctionNoProtoType(DestType,
                                                 FnType->getExtInfo());
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index f63ed09..09f04b7 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -1595,8 +1595,7 @@
       EPI.Variadic = Proto->isVariadic();
 
       ExpectedFunctionType
-        = Context.getFunctionType(Context.VoidTy, ArgTypes.data(),
-                                  ArgTypes.size(), EPI);
+        = Context.getFunctionType(Context.VoidTy, ArgTypes, EPI);
     }
 
     for (LookupResult::iterator D = FoundDelete.begin(),
@@ -1898,7 +1897,7 @@
                                 EST_BasicNoexcept : EST_DynamicNone;
   }
 
-  QualType FnType = Context.getFunctionType(Return, &Argument, 1, EPI);
+  QualType FnType = Context.getFunctionType(Return, Argument, EPI);
   FunctionDecl *Alloc =
     FunctionDecl::Create(Context, GlobalCtx, SourceLocation(),
                          SourceLocation(), Name,
diff --git a/lib/Sema/SemaLambda.cpp b/lib/Sema/SemaLambda.cpp
index 43e0c05..21202c1 100644
--- a/lib/Sema/SemaLambda.cpp
+++ b/lib/Sema/SemaLambda.cpp
@@ -385,7 +385,8 @@
     EPI.HasTrailingReturn = true;
     EPI.TypeQuals |= DeclSpec::TQ_const;
     QualType MethodTy = Context.getFunctionType(Context.DependentTy,
-                                                /*Args=*/0, /*NumArgs=*/0, EPI);
+                                                ArrayRef<QualType>(),
+                                                EPI);
     MethodTyInfo = Context.getTrivialTypeSourceInfo(MethodTy);
     ExplicitParams = false;
     ExplicitResultType = false;
@@ -628,16 +629,18 @@
   {
     FunctionProtoType::ExtProtoInfo ExtInfo = Proto->getExtProtoInfo();
     ExtInfo.TypeQuals = 0;
-    FunctionTy = S.Context.getFunctionType(Proto->getResultType(),
-                                           Proto->arg_type_begin(),
-                                           Proto->getNumArgs(),
-                                           ExtInfo);
+    FunctionTy =
+      S.Context.getFunctionType(Proto->getResultType(),
+                                ArrayRef<QualType>(Proto->arg_type_begin(),
+                                                   Proto->getNumArgs()),
+                                ExtInfo);
     FunctionPtrTy = S.Context.getPointerType(FunctionTy);
   }
   
   FunctionProtoType::ExtProtoInfo ExtInfo;
   ExtInfo.TypeQuals = Qualifiers::Const;
-  QualType ConvTy = S.Context.getFunctionType(FunctionPtrTy, 0, 0, ExtInfo);
+  QualType ConvTy =
+    S.Context.getFunctionType(FunctionPtrTy, ArrayRef<QualType>(), ExtInfo);
   
   SourceLocation Loc = IntroducerRange.getBegin();
   DeclarationName Name
@@ -701,15 +704,16 @@
     ExtInfo.TypeQuals = 0;
     QualType FunctionTy
       = S.Context.getFunctionType(Proto->getResultType(),
-                                  Proto->arg_type_begin(),
-                                  Proto->getNumArgs(),
+                                  ArrayRef<QualType>(Proto->arg_type_begin(),
+                                                     Proto->getNumArgs()),
                                   ExtInfo);
     BlockPtrTy = S.Context.getBlockPointerType(FunctionTy);
   }
   
   FunctionProtoType::ExtProtoInfo ExtInfo;
   ExtInfo.TypeQuals = Qualifiers::Const;
-  QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, 0, 0, ExtInfo);
+  QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, ArrayRef<QualType>(),
+                                              ExtInfo);
   
   SourceLocation Loc = IntroducerRange.getBegin();
   DeclarationName Name
@@ -821,8 +825,8 @@
         = CallOperator->getType()->getAs<FunctionProtoType>();
       QualType FunctionTy
         = Context.getFunctionType(LSI->ReturnType,
-                                  Proto->arg_type_begin(),
-                                  Proto->getNumArgs(),
+                                  ArrayRef<QualType>(Proto->arg_type_begin(),
+                                                     Proto->getNumArgs()),
                                   Proto->getExtProtoInfo());
       CallOperator->setType(FunctionTy);
     }
diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index d931bc7..eae6269 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -722,7 +722,7 @@
     EPI.NumExceptions = 0;
     QualType ExpectedType
       = R.getSema().Context.getFunctionType(R.getLookupName().getCXXNameType(),
-                                            0, 0, EPI);
+                                            ArrayRef<QualType>(), EPI);
 
     // Perform template argument deduction against the type that we would
     // expect the function to have.
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 4b766a9..75f255e 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -5946,8 +5946,9 @@
           FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
           EPI.TypeQuals |= Qualifiers::Const;
           FT = Context.getFunctionType(FPT->getResultType(),
-                                       FPT->arg_type_begin(),
-                                       FPT->getNumArgs(), EPI);
+                                       ArrayRef<QualType>(FPT->arg_type_begin(),
+                                                          FPT->getNumArgs()),
+                                       EPI);
         }
       }
 
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 421633f..c479895 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2417,8 +2417,7 @@
     return TDK_SubstitutionFailure;
 
   if (FunctionType) {
-    *FunctionType = BuildFunctionType(ResultType,
-                                      ParamTypes.data(), ParamTypes.size(),
+    *FunctionType = BuildFunctionType(ResultType, ParamTypes,
                                       Proto->isVariadic(),
                                       Proto->hasTrailingReturn(),
                                       Proto->getTypeQuals(),
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 9ca44c0..d54ca31 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1090,8 +1090,8 @@
   FunctionProtoType::ExtProtoInfo NewEPI = NewFunc->getExtProtoInfo();
   NewEPI.ExtInfo = OrigFunc->getExtInfo();
   return Context.getFunctionType(NewFunc->getResultType(),
-                                 NewFunc->arg_type_begin(),
-                                 NewFunc->getNumArgs(),
+                                 ArrayRef<QualType>(NewFunc->arg_type_begin(),
+                                                    NewFunc->getNumArgs()),
                                  NewEPI);
 }
 
@@ -2585,8 +2585,8 @@
   EPI.NoexceptExpr = NoexceptExpr;
 
   New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
-                                               NewProto->arg_type_begin(),
-                                               NewProto->getNumArgs(),
+                                  ArrayRef<QualType>(NewProto->arg_type_begin(),
+                                                     NewProto->getNumArgs()),
                                                EPI));
 }
 
@@ -2604,8 +2604,8 @@
     FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();
     EPI.ExceptionSpecType = EST_None;
     Decl->setType(Context.getFunctionType(Proto->getResultType(),
-                                          Proto->arg_type_begin(),
-                                          Proto->getNumArgs(),
+                                    ArrayRef<QualType>(Proto->arg_type_begin(),
+                                                       Proto->getNumArgs()),
                                           EPI));
     return;
   }
@@ -2685,8 +2685,8 @@
       EPI.ExceptionSpecDecl = New;
       EPI.ExceptionSpecTemplate = ExceptionSpecTemplate;
       New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
-                                                   NewProto->arg_type_begin(),
-                                                   NewProto->getNumArgs(),
+                                  ArrayRef<QualType>(NewProto->arg_type_begin(),
+                                                     NewProto->getNumArgs()),
                                                    EPI));
     } else {
       ::InstantiateExceptionSpec(SemaRef, New, Proto, TemplateArgs);
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index 0175177..fb25a16 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -1630,40 +1630,8 @@
   return Context.getDependentSizedExtVectorType(T, ArraySize, AttrLoc);
 }
 
-/// \brief Build a function type.
-///
-/// This routine checks the function type according to C++ rules and
-/// under the assumption that the result type and parameter types have
-/// just been instantiated from a template. It therefore duplicates
-/// some of the behavior of GetTypeForDeclarator, but in a much
-/// simpler form that is only suitable for this narrow use case.
-///
-/// \param T The return type of the function.
-///
-/// \param ParamTypes The parameter types of the function. This array
-/// will be modified to account for adjustments to the types of the
-/// function parameters.
-///
-/// \param NumParamTypes The number of parameter types in ParamTypes.
-///
-/// \param Variadic Whether this is a variadic function type.
-///
-/// \param HasTrailingReturn Whether this function has a trailing return type.
-///
-/// \param Quals The cvr-qualifiers to be applied to the function type.
-///
-/// \param Loc The location of the entity whose type involves this
-/// function type or, if there is no such entity, the location of the
-/// type that will have function type.
-///
-/// \param Entity The name of the entity that involves the function
-/// type, if known.
-///
-/// \returns A suitable function type, if there are no
-/// errors. Otherwise, returns a NULL type.
 QualType Sema::BuildFunctionType(QualType T,
-                                 QualType *ParamTypes,
-                                 unsigned NumParamTypes,
+                                 llvm::MutableArrayRef<QualType> ParamTypes,
                                  bool Variadic, bool HasTrailingReturn,
                                  unsigned Quals,
                                  RefQualifierKind RefQualifier,
@@ -1683,7 +1651,7 @@
   }
 
   bool Invalid = false;
-  for (unsigned Idx = 0; Idx < NumParamTypes; ++Idx) {
+  for (unsigned Idx = 0, Cnt = ParamTypes.size(); Idx < Cnt; ++Idx) {
     // FIXME: Loc is too inprecise here, should use proper locations for args.
     QualType ParamType = Context.getAdjustedParameterType(ParamTypes[Idx]);
     if (ParamType->isVoidType()) {
@@ -1709,7 +1677,7 @@
   EPI.RefQualifier = RefQualifier;
   EPI.ExtInfo = Info;
 
-  return Context.getFunctionType(T, ParamTypes, NumParamTypes, EPI);
+  return Context.getFunctionType(T, ParamTypes, EPI);
 }
 
 /// \brief Build a member pointer type \c T Class::*.
@@ -2786,7 +2754,7 @@
                                       Exceptions,
                                       EPI);
 
-        T = Context.getFunctionType(T, ArgTys.data(), ArgTys.size(), EPI);
+        T = Context.getFunctionType(T, ArgTys, EPI);
       }
 
       break;
@@ -2926,8 +2894,9 @@
       EPI.RefQualifier = RQ_None;
 
       T = Context.getFunctionType(FnTy->getResultType(),
-                                  FnTy->arg_type_begin(),
-                                  FnTy->getNumArgs(), EPI);
+                                  ArrayRef<QualType>(FnTy->arg_type_begin(),
+                                                     FnTy->getNumArgs()),
+                                  EPI);
       // Rebuild any parens around the identifier in the function type.
       for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
         if (D.getTypeObject(i).Kind != DeclaratorChunk::Paren)
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index c2dcf74..af82aba 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -713,8 +713,7 @@
   /// By default, performs semantic analysis when building the function type.
   /// Subclasses may override this routine to provide different behavior.
   QualType RebuildFunctionProtoType(QualType T,
-                                    QualType *ParamTypes,
-                                    unsigned NumParamTypes,
+                                    llvm::MutableArrayRef<QualType> ParamTypes,
                                     bool Variadic, bool HasTrailingReturn,
                                     unsigned Quals,
                                     RefQualifierKind RefQualifier,
@@ -4266,9 +4265,7 @@
       ResultType != T->getResultType() ||
       T->getNumArgs() != ParamTypes.size() ||
       !std::equal(T->arg_type_begin(), T->arg_type_end(), ParamTypes.begin())) {
-    Result = getDerived().RebuildFunctionProtoType(ResultType,
-                                                   ParamTypes.data(),
-                                                   ParamTypes.size(),
+    Result = getDerived().RebuildFunctionProtoType(ResultType, ParamTypes,
                                                    T->isVariadic(),
                                                    T->hasTrailingReturn(),
                                                    T->getTypeQuals(),
@@ -8850,13 +8847,11 @@
     return ExprError();
   }
 
-  QualType functionType = getDerived().RebuildFunctionProtoType(
-                                                        exprResultType,
-                                                        paramTypes.data(),
-                                                        paramTypes.size(),
-                                                        oldBlock->isVariadic(),
-                                                        false, 0, RQ_None,
-                                               exprFunctionType->getExtInfo());
+  QualType functionType =
+    getDerived().RebuildFunctionProtoType(exprResultType, paramTypes,
+                                          oldBlock->isVariadic(),
+                                          false, 0, RQ_None,
+                                          exprFunctionType->getExtInfo());
   blockScope->FunctionType = functionType;
 
   // Set the parameters on the block decl.
@@ -9072,15 +9067,15 @@
 }
 
 template<typename Derived>
-QualType TreeTransform<Derived>::RebuildFunctionProtoType(QualType T,
-                                                          QualType *ParamTypes,
-                                                        unsigned NumParamTypes,
-                                                          bool Variadic,
-                                                         bool HasTrailingReturn,
-                                                          unsigned Quals,
-                                                  RefQualifierKind RefQualifier,
-                                            const FunctionType::ExtInfo &Info) {
-  return SemaRef.BuildFunctionType(T, ParamTypes, NumParamTypes, Variadic,
+QualType TreeTransform<Derived>::RebuildFunctionProtoType(
+    QualType T,
+    llvm::MutableArrayRef<QualType> ParamTypes,
+    bool Variadic,
+    bool HasTrailingReturn,
+    unsigned Quals,
+    RefQualifierKind RefQualifier,
+    const FunctionType::ExtInfo &Info) {
+  return SemaRef.BuildFunctionType(T, ParamTypes, Variadic,
                                    HasTrailingReturn, Quals, RefQualifier,
                                    getDerived().getBaseLocation(),
                                    getDerived().getBaseEntity(),
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 743204e..93ae6f1 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -4395,8 +4395,7 @@
     } else if (EST == EST_Unevaluated) {
       EPI.ExceptionSpecDecl = ReadDeclAs<FunctionDecl>(*Loc.F, Record, Idx);
     }
-    return Context.getFunctionType(ResultType, ParamTypes.data(), NumParams,
-                                    EPI);
+    return Context.getFunctionType(ResultType, ParamTypes, EPI);
   }
 
   case TYPE_UNRESOLVED_USING: {