diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 49a118c..ab4f21e 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -20,6 +20,7 @@
 #include "clang/AST/DeclarationName.h"
 #include "clang/AST/ExternalASTSource.h"
 #include "clang/Basic/Linkage.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
 
 namespace clang {
@@ -1480,7 +1481,7 @@
   void setInstantiationOfMemberFunction(ASTContext &C, FunctionDecl *FD,
                                         TemplateSpecializationKind TSK);
 
-  void setParams(ASTContext &C, ParmVarDecl **NewParamInfo, unsigned NumParams);
+  void setParams(ASTContext &C, llvm::ArrayRef<ParmVarDecl *> NewParamInfo);
 
 protected:
   FunctionDecl(Kind DK, DeclContext *DC, SourceLocation StartLoc,
@@ -1750,8 +1751,8 @@
     assert(i < getNumParams() && "Illegal param #");
     return ParamInfo[i];
   }
-  void setParams(ParmVarDecl **NewParamInfo, unsigned NumParams) {
-    setParams(getASTContext(), NewParamInfo, NumParams);
+  void setParams(llvm::ArrayRef<ParmVarDecl *> NewParamInfo) {
+    setParams(getASTContext(), NewParamInfo);
   }
 
   /// getMinRequiredArguments - Returns the minimum number of arguments
@@ -2997,7 +2998,7 @@
     assert(i < getNumParams() && "Illegal param #");
     return ParamInfo[i];
   }
-  void setParams(ParmVarDecl **NewParamInfo, unsigned NumParams);
+  void setParams(llvm::ArrayRef<ParmVarDecl *> NewParamInfo);
 
   /// hasCaptures - True if this block (or its nested blocks) captures
   /// anything of local storage from its enclosing scopes.
diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index cee63b9..1a2e02f 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -2521,7 +2521,7 @@
     Parameters[I]->setOwningFunction(ToFunction);
     ToFunction->addDecl(Parameters[I]);
   }
-  ToFunction->setParams(Parameters.data(), Parameters.size());
+  ToFunction->setParams(Parameters);
 
   // FIXME: Other bits to merge?
 
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 73a6558..3a2d532 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -28,6 +28,8 @@
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/Support/ErrorHandling.h"
 
+#include <algorithm>
+
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
@@ -1688,15 +1690,14 @@
 }
 
 void FunctionDecl::setParams(ASTContext &C,
-                             ParmVarDecl **NewParamInfo, unsigned NumParams) {
+                             llvm::ArrayRef<ParmVarDecl *> NewParamInfo) {
   assert(ParamInfo == 0 && "Already has param info!");
-  assert(NumParams == getNumParams() && "Parameter count mismatch!");
+  assert(NewParamInfo.size() == getNumParams() && "Parameter count mismatch!");
 
   // Zero params -> null pointer.
-  if (NumParams) {
-    void *Mem = C.Allocate(sizeof(ParmVarDecl*)*NumParams);
-    ParamInfo = new (Mem) ParmVarDecl*[NumParams];
-    memcpy(ParamInfo, NewParamInfo, sizeof(ParmVarDecl*)*NumParams);
+  if (!NewParamInfo.empty()) {
+    ParamInfo = new (C) ParmVarDecl*[NewParamInfo.size()];
+    std::copy(NewParamInfo.begin(), NewParamInfo.end(), ParamInfo);
   }
 }
 
@@ -2430,16 +2431,14 @@
 // BlockDecl Implementation
 //===----------------------------------------------------------------------===//
 
-void BlockDecl::setParams(ParmVarDecl **NewParamInfo,
-                          unsigned NParms) {
+void BlockDecl::setParams(llvm::ArrayRef<ParmVarDecl *> NewParamInfo) {
   assert(ParamInfo == 0 && "Already has param info!");
 
   // Zero params -> null pointer.
-  if (NParms) {
-    NumParams = NParms;
-    void *Mem = getASTContext().Allocate(sizeof(ParmVarDecl*)*NumParams);
-    ParamInfo = new (Mem) ParmVarDecl*[NumParams];
-    memcpy(ParamInfo, NewParamInfo, sizeof(ParmVarDecl*)*NumParams);
+  if (!NewParamInfo.empty()) {
+    NumParams = NewParamInfo.size();
+    ParamInfo = new (getASTContext()) ParmVarDecl*[NewParamInfo.size()];
+    std::copy(NewParamInfo.begin(), NewParamInfo.end(), ParamInfo);
   }
 }
 
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 164fb2f..1057def 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1290,7 +1290,7 @@
       parm->setScopeInfo(0, i);
       Params.push_back(parm);
     }
-    New->setParams(Params.data(), Params.size());
+    New->setParams(Params);
   }
 
   AddKnownFunctionAttributes(New);
@@ -1853,7 +1853,7 @@
         Params.push_back(Param);
       }
 
-      New->setParams(Params.data(), Params.size());
+      New->setParams(Params);
     }
 
     return MergeCompatibleFunctionDecls(New, Old);
@@ -4873,7 +4873,7 @@
            "Should not need args for typedef of non-prototype fn");
   }
   // Finally, we know we have the right number of parameters, install them.
-  NewFD->setParams(Params.data(), Params.size());
+  NewFD->setParams(Params);
 
   // Process the non-inheritable attributes on this declaration.
   ProcessDeclAttributes(S, NewFD, D,
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 1f97d40..48f2f96 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -3674,7 +3674,7 @@
         Param->setScopeInfo(0, Params.size());
         Params.push_back(Param);
       }
-      NewFD->setParams(Params.data(), Params.size());
+      NewFD->setParams(Params);
     }
   } else if (VarDecl *VD = dyn_cast<VarDecl>(ND)) {
     NewD = VarDecl::Create(VD->getASTContext(), VD->getDeclContext(),
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 0d83d9f..f9787e8 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -6835,7 +6835,7 @@
                                                    /*TInfo=*/0, SC_None,
                                                    SC_None, /*DefaultArg=*/0));
         }
-        NewCtor->setParams(ParamDecls.data(), ParamDecls.size());
+        NewCtor->setParams(ParamDecls);
         NewCtor->setInheritedConstructor(BaseCtor);
 
         PushOnScopeChains(NewCtor, S, false);
@@ -7353,7 +7353,7 @@
                                                ArgType, /*TInfo=*/0,
                                                SC_None,
                                                SC_None, 0);
-  CopyAssignment->setParams(&FromParam, 1);
+  CopyAssignment->setParams(FromParam);
   
   // Note that we have added this copy-assignment operator.
   ++ASTContext::NumImplicitCopyAssignmentOperatorsDeclared;
@@ -7768,7 +7768,7 @@
                                                ArgType, /*TInfo=*/0,
                                                SC_None,
                                                SC_None, 0);
-  MoveAssignment->setParams(&FromParam, 1);
+  MoveAssignment->setParams(FromParam);
 
   // Note that we have added this copy-assignment operator.
   ++ASTContext::NumImplicitMoveAssignmentOperatorsDeclared;
@@ -8259,7 +8259,7 @@
                                                ArgType, /*TInfo=*/0,
                                                SC_None,
                                                SC_None, 0);
-  CopyConstructor->setParams(&FromParam, 1);
+  CopyConstructor->setParams(FromParam);
 
   if (Scope *S = getScopeForContext(ClassDecl))
     PushOnScopeChains(CopyConstructor, S, false);
@@ -8416,7 +8416,7 @@
                                                ArgType, /*TInfo=*/0,
                                                SC_None,
                                                SC_None, 0);
-  MoveConstructor->setParams(&FromParam, 1);
+  MoveConstructor->setParams(FromParam);
 
   // C++0x [class.copy]p9:
   //   If the definition of a class X does not explicitly declare a move
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index cafed19..1d23f4f 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -8710,7 +8710,7 @@
 
   // Set the parameters on the block decl.
   if (!Params.empty()) {
-    CurBlock->TheDecl->setParams(Params.data(), Params.size());
+    CurBlock->TheDecl->setParams(Params);
     CheckParmsForFunctionDef(CurBlock->TheDecl->param_begin(),
                              CurBlock->TheDecl->param_end(),
                              /*CheckParameterNames=*/false);
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 1741bdb..140fd90 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -1671,7 +1671,7 @@
                                            SourceLocation(), 0,
                                            Argument, /*TInfo=*/0,
                                            SC_None, SC_None, 0);
-  Alloc->setParams(&Param, 1);
+  Alloc->setParams(Param);
 
   // FIXME: Also add this declaration to the IdentifierResolver, but
   // make sure it is at the end of the chain to coincide with the
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 43806c6..4391e7a 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1112,7 +1112,7 @@
       Params.push_back(Param);
     }
   }
-  Function->setParams(Params.data(), Params.size());
+  Function->setParams(Params);
 
   SourceLocation InstantiateAtPOI;
   if (TemplateParams) {
@@ -1485,7 +1485,7 @@
   // Attach the parameters
   for (unsigned P = 0; P < Params.size(); ++P)
     Params[P]->setOwningFunction(Method);
-  Method->setParams(Params.data(), Params.size());
+  Method->setParams(Params);
 
   if (InitMethodInstantiation(Method, D))
     Method->setInvalidDecl();
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 12eba29..32e8a0e 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -7989,7 +7989,7 @@
 
   // Set the parameters on the block decl.
   if (!params.empty())
-    blockScope->TheDecl->setParams(params.data(), params.size());
+    blockScope->TheDecl->setParams(params);
   
   // If the return type wasn't explicitly set, it will have been marked as a 
   // dependent type (DependentTy); clear out the return type setting so 
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 4448889..77b05fd 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -465,7 +465,7 @@
   Params.reserve(NumParams);
   for (unsigned I = 0; I != NumParams; ++I)
     Params.push_back(ReadDeclAs<ParmVarDecl>(Record, Idx));
-  FD->setParams(Reader.getContext(), Params.data(), NumParams);
+  FD->setParams(Reader.getContext(), Params);
 }
 
 void ASTDeclReader::VisitObjCMethodDecl(ObjCMethodDecl *MD) {
@@ -758,7 +758,7 @@
   Params.reserve(NumParams);
   for (unsigned I = 0; I != NumParams; ++I)
     Params.push_back(ReadDeclAs<ParmVarDecl>(Record, Idx));
-  BD->setParams(Params.data(), NumParams);
+  BD->setParams(Params);
 
   bool capturesCXXThis = Record[Idx++];
   unsigned numCaptures = Record[Idx++];