[ms-cxxabi] The 'most derived' ctor parameter usually comes last

Unlike Itanium's VTTs, the 'most derived' boolean or bitfield is the
last parameter for non-variadic constructors, rather than the second.
For variadic constructors, the 'most derived' parameter comes after the
'this' parameter.  This affects constructor calls and constructor decls
in a variety of places.

Reviewers: timurrrr

Differential Revision: http://llvm-reviews.chandlerc.com/D2405

llvm-svn: 197518

1 files changed, 5 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 726e808ed08..50cbdb1b071 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -202,16 +202,17 @@ CodeGenTypes::arrangeCXXConstructorDeclaration(const CXXConstructorDecl *D,
   CanQualType resultType =
     TheCXXABI.HasThisReturn(GD) ? argTypes.front() : Context.VoidTy;
 
-  TheCXXABI.BuildConstructorSignature(D, ctorKind, resultType, argTypes);
-
   CanQual<FunctionProtoType> FTP = GetFormalType(D);
 
-  RequiredArgs required = RequiredArgs::forPrototypePlus(FTP, argTypes.size());
-
   // Add the formal parameters.
   for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
     argTypes.push_back(FTP->getArgType(i));
 
+  TheCXXABI.BuildConstructorSignature(D, ctorKind, resultType, argTypes);
+
+  RequiredArgs required =
+      (D->isVariadic() ? RequiredArgs(argTypes.size()) : RequiredArgs::All);
+
   FunctionType::ExtInfo extInfo = FTP->getExtInfo();
   return arrangeLLVMFunctionInfo(resultType, argTypes, extInfo, required);
 }