Add a ReturnValueSlot class. Change the argument order in EmitCall to match the other overload better.

llvm-svn: 92136
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index c2e59c0..d28dd47 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -1039,7 +1039,7 @@
                   const CallArgList &Args,
                   const Decl *TargetDecl = 0);
 
-  RValue EmitCall(llvm::Value *Callee, QualType FnType,
+  RValue EmitCall(QualType FnType, llvm::Value *Callee,
                   CallExpr::const_arg_iterator ArgBeg,
                   CallExpr::const_arg_iterator ArgEnd,
                   const Decl *TargetDecl = 0);