diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 3f10612..072b1f6 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -44,28 +44,29 @@
 /// Derives the 'this' type for codegen purposes, i.e. ignoring method
 /// qualification.
 /// FIXME: address space qualification?
-static QualType GetThisType(ASTContext &Context, const CXXRecordDecl *RD) {
-  return Context.getPointerType(Context.getTagDeclType(RD));
+static CanQualType GetThisType(ASTContext &Context, const CXXRecordDecl *RD) {
+  QualType RecTy = Context.getTagDeclType(RD)->getCanonicalTypeInternal();
+  return Context.getPointerType(CanQualType::CreateUnsafe(RecTy));
 }
 
 /// Returns the canonical formal type of the given C++ method.
-static const FunctionProtoType *GetFormalType(const CXXMethodDecl *MD) {
-  return cast<FunctionProtoType>(MD->getType()->getCanonicalTypeInternal());
+static CanQual<FunctionProtoType> GetFormalType(const CXXMethodDecl *MD) {
+  return MD->getType()->getCanonicalTypeUnqualified()
+           .getAs<FunctionProtoType>();
 }
 
 /// Returns the "extra-canonicalized" return type, which discards
 /// qualifiers on the return type.  Codegen doesn't care about them,
 /// and it makes ABI code a little easier to be able to assume that
 /// all parameter and return types are top-level unqualified.
-static QualType GetReturnType(QualType RetTy) {
-  return RetTy->getCanonicalTypeInternal().getUnqualifiedType();
+static CanQualType GetReturnType(QualType RetTy) {
+  return RetTy->getCanonicalTypeUnqualified().getUnqualifiedType();
 }
 
 const CGFunctionInfo &
-CodeGenTypes::getFunctionInfo(const FunctionNoProtoType *FTNP) {
-  assert(FTNP->isCanonicalUnqualified() && "type must be canonical");
-  return getFunctionInfo(GetReturnType(FTNP->getResultType()),
-                         llvm::SmallVector<QualType, 16>(),
+CodeGenTypes::getFunctionInfo(CanQual<FunctionNoProtoType> FTNP) {
+  return getFunctionInfo(FTNP->getResultType().getUnqualifiedType(),
+                         llvm::SmallVector<CanQualType, 16>(),
                          FTNP->getCallConv(),
                          FTNP->getNoReturnAttr());
 }
@@ -73,21 +74,20 @@
 /// \param Args - contains any initial parameters besides those
 ///   in the formal type
 static const CGFunctionInfo &getFunctionInfo(CodeGenTypes &CGT,
-                                       llvm::SmallVectorImpl<QualType> &ArgTys,
-                                             const FunctionProtoType *FTP) {
-  assert(FTP->isCanonicalUnqualified() && "type must be canonical");
+                                  llvm::SmallVectorImpl<CanQualType> &ArgTys,
+                                             CanQual<FunctionProtoType> FTP) {
   // FIXME: Kill copy.
   for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
     ArgTys.push_back(FTP->getArgType(i));
-  return CGT.getFunctionInfo(GetReturnType(FTP->getResultType()),
-                             ArgTys,
+  CanQualType ResTy = FTP->getResultType().getUnqualifiedType();
+  return CGT.getFunctionInfo(ResTy, ArgTys,
                              FTP->getCallConv(),
                              FTP->getNoReturnAttr());
 }
 
 const CGFunctionInfo &
-CodeGenTypes::getFunctionInfo(const FunctionProtoType *FTP) {
-  llvm::SmallVector<QualType, 16> ArgTys;
+CodeGenTypes::getFunctionInfo(CanQual<FunctionProtoType> FTP) {
+  llvm::SmallVector<CanQualType, 16> ArgTys;
   return ::getFunctionInfo(*this, ArgTys, FTP);
 }
 
@@ -104,17 +104,17 @@
 
 const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXRecordDecl *RD,
                                                  const FunctionProtoType *FTP) {
-  llvm::SmallVector<QualType, 16> ArgTys;
+  llvm::SmallVector<CanQualType, 16> ArgTys;
 
   // Add the 'this' pointer.
   ArgTys.push_back(GetThisType(Context, RD));
 
   return ::getFunctionInfo(*this, ArgTys,
-                   cast<FunctionProtoType>(FTP->getCanonicalTypeInternal()));
+              FTP->getCanonicalTypeUnqualified().getAs<FunctionProtoType>());
 }
 
 const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXMethodDecl *MD) {
-  llvm::SmallVector<QualType, 16> ArgTys;
+  llvm::SmallVector<CanQualType, 16> ArgTys;
 
   // Add the 'this' pointer unless this is a static method.
   if (MD->isInstance())
@@ -125,7 +125,7 @@
 
 const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXConstructorDecl *D, 
                                                     CXXCtorType Type) {
-  llvm::SmallVector<QualType, 16> ArgTys;
+  llvm::SmallVector<CanQualType, 16> ArgTys;
 
   // Add the 'this' pointer.
   ArgTys.push_back(GetThisType(Context, D->getParent()));
@@ -139,10 +139,10 @@
 
 const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXDestructorDecl *D,
                                                     CXXDtorType Type) {
-  llvm::SmallVector<QualType, 16> ArgTys;
+  llvm::SmallVector<CanQualType, 16> ArgTys;
   
   // Add the 'this' pointer.
-  ArgTys.push_back(D->getThisType(Context));
+  ArgTys.push_back(GetThisType(Context, D->getParent()));
   
   // Check if we need to add a VTT parameter (which has type void **).
   if (Type == Dtor_Base && D->getParent()->getNumVBases() != 0)
@@ -156,17 +156,18 @@
     if (MD->isInstance())
       return getFunctionInfo(MD);
 
-  const FunctionType *FTy
-    = cast<FunctionType>(FD->getType()->getCanonicalTypeInternal());
+  CanQualType FTy = FD->getType()->getCanonicalTypeUnqualified();
+  assert(isa<FunctionType>(FTy));
   if (isa<FunctionNoProtoType>(FTy))
-    return getFunctionInfo(cast<FunctionNoProtoType>(FTy));  
-  return getFunctionInfo(cast<FunctionProtoType>(FTy));
+    return getFunctionInfo(FTy.getAs<FunctionNoProtoType>());  
+  assert(isa<FunctionProtoType>(FTy));
+  return getFunctionInfo(FTy.getAs<FunctionProtoType>());
 }
 
 const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const ObjCMethodDecl *MD) {
-  llvm::SmallVector<QualType, 16> ArgTys;
-  ArgTys.push_back(MD->getSelfDecl()->getType());
-  ArgTys.push_back(Context.getObjCSelType());
+  llvm::SmallVector<CanQualType, 16> ArgTys;
+  ArgTys.push_back(Context.getCanonicalParamType(MD->getSelfDecl()->getType()));
+  ArgTys.push_back(Context.getCanonicalParamType(Context.getObjCSelType()));
   // FIXME: Kill copy?
   for (ObjCMethodDecl::param_iterator i = MD->param_begin(),
          e = MD->param_end(); i != e; ++i) {
@@ -196,7 +197,7 @@
                                                     CallingConv CC,
                                                     bool NoReturn) {
   // FIXME: Kill copy.
-  llvm::SmallVector<QualType, 16> ArgTys;
+  llvm::SmallVector<CanQualType, 16> ArgTys;
   for (CallArgList::const_iterator i = Args.begin(), e = Args.end();
        i != e; ++i)
     ArgTys.push_back(Context.getCanonicalParamType(i->second));
@@ -208,17 +209,23 @@
                                                     CallingConv CC,
                                                     bool NoReturn) {
   // FIXME: Kill copy.
-  llvm::SmallVector<QualType, 16> ArgTys;
+  llvm::SmallVector<CanQualType, 16> ArgTys;
   for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
        i != e; ++i)
     ArgTys.push_back(Context.getCanonicalParamType(i->second));
   return getFunctionInfo(GetReturnType(ResTy), ArgTys, CC, NoReturn);
 }
 
-const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy,
-                           const llvm::SmallVectorImpl<QualType> &ArgTys,
+const CGFunctionInfo &CodeGenTypes::getFunctionInfo(CanQualType ResTy,
+                           const llvm::SmallVectorImpl<CanQualType> &ArgTys,
                                                     CallingConv CallConv,
                                                     bool NoReturn) {
+#ifndef NDEBUG
+  for (llvm::SmallVectorImpl<CanQualType>::const_iterator
+         I = ArgTys.begin(), E = ArgTys.end(); I != E; ++I)
+    assert(I->isCanonicalAsParam());
+#endif
+
   unsigned CC = ClangCallConvToLLVMCallConv(CallConv);
 
   // Lookup or create unique function info.
@@ -243,8 +250,8 @@
 
 CGFunctionInfo::CGFunctionInfo(unsigned _CallingConvention,
                                bool _NoReturn,
-                               QualType ResTy,
-                               const llvm::SmallVectorImpl<QualType> &ArgTys) 
+                               CanQualType ResTy,
+                               const llvm::SmallVectorImpl<CanQualType> &ArgTys)
   : CallingConvention(_CallingConvention),
     EffectiveCallingConvention(_CallingConvention),
     NoReturn(_NoReturn)
diff --git a/lib/CodeGen/CGCall.h b/lib/CodeGen/CGCall.h
index 1d1b8ee..3d81165 100644
--- a/lib/CodeGen/CGCall.h
+++ b/lib/CodeGen/CGCall.h
@@ -18,6 +18,7 @@
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/Value.h"
 #include "clang/AST/Type.h"
+#include "clang/AST/CanonicalType.h"
 
 #include "CGValue.h"
 
@@ -57,7 +58,7 @@
   /// function definition.
   class CGFunctionInfo : public llvm::FoldingSetNode {
     struct ArgInfo {
-      QualType type;
+      CanQualType type;
       ABIArgInfo info;
     };
 
@@ -81,8 +82,8 @@
 
     CGFunctionInfo(unsigned CallingConvention,
                    bool NoReturn,
-                   QualType ResTy,
-                   const llvm::SmallVectorImpl<QualType> &ArgTys);
+                   CanQualType ResTy,
+                   const llvm::SmallVectorImpl<CanQualType> &ArgTys);
     ~CGFunctionInfo() { delete[] Args; }
 
     const_arg_iterator arg_begin() const { return Args + 1; }
@@ -107,7 +108,7 @@
       EffectiveCallingConvention = Value;
     }
 
-    QualType getReturnType() const { return Args[0].type; }
+    CanQualType getReturnType() const { return Args[0].type; }
 
     ABIArgInfo &getReturnInfo() { return Args[0].info; }
     const ABIArgInfo &getReturnInfo() const { return Args[0].info; }
@@ -123,14 +124,16 @@
     static void Profile(llvm::FoldingSetNodeID &ID,
                         unsigned CallingConvention,
                         bool NoReturn,
-                        QualType ResTy,
+                        CanQualType ResTy,
                         Iterator begin,
                         Iterator end) {
       ID.AddInteger(CallingConvention);
       ID.AddBoolean(NoReturn);
       ResTy.Profile(ID);
-      for (; begin != end; ++begin)
-        begin->Profile(ID);
+      for (; begin != end; ++begin) {
+        CanQualType T = *begin; // force iterator to be over canonical types
+        T.Profile(ID);
+      }
     }
   };
   
diff --git a/lib/CodeGen/CGObjCGNU.cpp b/lib/CodeGen/CGObjCGNU.cpp
index 1d38ef9..228054e 100644
--- a/lib/CodeGen/CGObjCGNU.cpp
+++ b/lib/CodeGen/CGObjCGNU.cpp
@@ -56,7 +56,7 @@
   const llvm::FunctionType *IMPTy;
   const llvm::PointerType *IdTy;
   const llvm::PointerType *PtrToIdTy;
-  QualType ASTIdTy;
+  CanQualType ASTIdTy;
   const llvm::IntegerType *IntTy;
   const llvm::PointerType *PtrTy;
   const llvm::IntegerType *LongTy;
@@ -262,7 +262,7 @@
   PtrTy = PtrToInt8Ty;
 
   // Object type
-  ASTIdTy = CGM.getContext().getObjCIdType();
+  ASTIdTy = CGM.getContext().getCanonicalType(CGM.getContext().getObjCIdType());
   if (QualType() == ASTIdTy) {
     IdTy = PtrToInt8Ty;
   } else {
@@ -1685,7 +1685,7 @@
   CodeGen::CodeGenTypes &Types = CGM.getTypes();
   ASTContext &Ctx = CGM.getContext();
   // void objc_enumerationMutation (id)
-  llvm::SmallVector<QualType,16> Params;
+  llvm::SmallVector<CanQualType,1> Params;
   Params.push_back(ASTIdTy);
   const llvm::FunctionType *FTy =
     Types.GetFunctionType(Types.getFunctionInfo(Ctx.VoidTy, Params,
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 5f9c518..475280b 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -297,9 +297,9 @@
     CodeGen::CodeGenTypes &Types = CGM.getTypes();
     ASTContext &Ctx = CGM.getContext();
     // id objc_getProperty (id, SEL, ptrdiff_t, bool)
-    llvm::SmallVector<QualType,16> Params;
-    QualType IdType = Ctx.getObjCIdType();
-    QualType SelType = Ctx.getObjCSelType();
+    llvm::SmallVector<CanQualType,4> Params;
+    CanQualType IdType = Ctx.getCanonicalParamType(Ctx.getObjCIdType());
+    CanQualType SelType = Ctx.getCanonicalParamType(Ctx.getObjCSelType());
     Params.push_back(IdType);
     Params.push_back(SelType);
     Params.push_back(Ctx.LongTy);
@@ -314,9 +314,9 @@
     CodeGen::CodeGenTypes &Types = CGM.getTypes();
     ASTContext &Ctx = CGM.getContext();
     // void objc_setProperty (id, SEL, ptrdiff_t, id, bool, bool)
-    llvm::SmallVector<QualType,16> Params;
-    QualType IdType = Ctx.getObjCIdType();
-    QualType SelType = Ctx.getObjCSelType();
+    llvm::SmallVector<CanQualType,6> Params;
+    CanQualType IdType = Ctx.getCanonicalParamType(Ctx.getObjCIdType());
+    CanQualType SelType = Ctx.getCanonicalParamType(Ctx.getObjCSelType());
     Params.push_back(IdType);
     Params.push_back(SelType);
     Params.push_back(Ctx.LongTy);
@@ -333,8 +333,8 @@
     CodeGen::CodeGenTypes &Types = CGM.getTypes();
     ASTContext &Ctx = CGM.getContext();
     // void objc_enumerationMutation (id)
-    llvm::SmallVector<QualType,16> Params;
-    Params.push_back(Ctx.getObjCIdType());
+    llvm::SmallVector<CanQualType,1> Params;
+    Params.push_back(Ctx.getCanonicalParamType(Ctx.getObjCIdType()));
     const llvm::FunctionType *FTy =
       Types.GetFunctionType(Types.getFunctionInfo(Ctx.VoidTy, Params,
                                                   CC_Default, false), false);
@@ -5093,9 +5093,8 @@
   // Find the message function name.
   // FIXME. This is too much work to get the ABI-specific result type needed to
   // find the message name.
-  const CGFunctionInfo &FnInfo = Types.getFunctionInfo(ResultType,
-                                                       llvm::SmallVector<QualType, 16>(),
-                                                       CC_Default, false);
+  const CGFunctionInfo &FnInfo
+    = Types.getFunctionInfo(ResultType, CallArgList(), CC_Default, false);
   llvm::Constant *Fn = 0;
   std::string Name("\01l_");
   if (CGM.ReturnTypeUsesSret(FnInfo)) {
diff --git a/lib/CodeGen/CodeGenTypes.cpp b/lib/CodeGen/CodeGenTypes.cpp
index 3c20934..f30e03c 100644
--- a/lib/CodeGen/CodeGenTypes.cpp
+++ b/lib/CodeGen/CodeGenTypes.cpp
@@ -313,10 +313,14 @@
     // The function type can be built; call the appropriate routines to
     // build it.
     if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(&Ty))
-      return GetFunctionType(getFunctionInfo(FPT), FPT->isVariadic());
+      return GetFunctionType(getFunctionInfo(
+                CanQual<FunctionProtoType>::CreateUnsafe(QualType(FPT,0))),
+                             FPT->isVariadic());
 
     const FunctionNoProtoType *FNPT = cast<FunctionNoProtoType>(&Ty);
-    return GetFunctionType(getFunctionInfo(FNPT), true);
+    return GetFunctionType(getFunctionInfo(
+                CanQual<FunctionNoProtoType>::CreateUnsafe(QualType(FNPT,0))),
+                           true);
   }
 
   case Type::ObjCInterface: {
diff --git a/lib/CodeGen/CodeGenTypes.h b/lib/CodeGen/CodeGenTypes.h
index f2e12ca..b2912ef 100644
--- a/lib/CodeGen/CodeGenTypes.h
+++ b/lib/CodeGen/CodeGenTypes.h
@@ -35,6 +35,7 @@
 namespace clang {
   class ABIInfo;
   class ASTContext;
+  template <typename> class CanQual;
   class CXXConstructorDecl;
   class CXXDestructorDecl;
   class CXXMethodDecl;
@@ -48,6 +49,7 @@
   class TagDecl;
   class TargetInfo;
   class Type;
+  typedef CanQual<Type> CanQualType;
 
 namespace CodeGen {
   class CodeGenTypes;
@@ -202,8 +204,8 @@
     return getFunctionInfo(Ty->getResultType(), Args,
                            Ty->getCallConv(), Ty->getNoReturnAttr());
   }
-  const CGFunctionInfo &getFunctionInfo(const FunctionProtoType *Ty);
-  const CGFunctionInfo &getFunctionInfo(const FunctionNoProtoType *Ty);
+  const CGFunctionInfo &getFunctionInfo(CanQual<FunctionProtoType> Ty);
+  const CGFunctionInfo &getFunctionInfo(CanQual<FunctionNoProtoType> Ty);
 
   // getFunctionInfo - Get the function info for a member function.
   const CGFunctionInfo &getFunctionInfo(const CXXRecordDecl *RD,
@@ -220,8 +222,12 @@
                                         const FunctionArgList &Args,
                                         CallingConv CC,
                                         bool NoReturn);
-  const CGFunctionInfo &getFunctionInfo(QualType RetTy,
-                                  const llvm::SmallVectorImpl<QualType> &ArgTys,
+
+  /// Retrieves the ABI information for the given function signature.
+  /// 
+  /// \param ArgTys - must all actually be canonical as params
+  const CGFunctionInfo &getFunctionInfo(CanQualType RetTy,
+                               const llvm::SmallVectorImpl<CanQualType> &ArgTys,
                                         CallingConv CC,
                                         bool NoReturn);