Fix type in cbuffer annotation when converting to legacy layout

Copy of original annotation would copy original struct type,
instead of one for legacy layout.  This leads to internal validation
using a different type when validating cbuffer layout than external
validation would use, since this member would be synthesized by the
key, rather than saved and restored directly.

include/dxc/DXIL/DxilTypeSystem.h

@@ -100,6 +100,7 @@ public:
   DxilFieldAnnotation &GetFieldAnnotation(unsigned FieldIdx);
   const DxilFieldAnnotation &GetFieldAnnotation(unsigned FieldIdx) const;
   const llvm::StructType *GetStructType() const;
+  void SetStructType(const llvm::StructType *Ty);
   unsigned GetCBufferSize() const;
   void SetCBufferSize(unsigned size);
   void MarkEmptyStruct();

lib/DXIL/DxilTypeSystem.cpp

@@ -97,6 +97,10 @@ const DxilFieldAnnotation &DxilStructAnnotation::GetFieldAnnotation(unsigned Fie
 const StructType *DxilStructAnnotation::GetStructType() const {
   return m_pStructType;
 }
+void DxilStructAnnotation::SetStructType(const llvm::StructType *Ty) {
+  m_pStructType = Ty;
+}
+
 
 unsigned DxilStructAnnotation::GetCBufferSize() const { return m_CBufferSize; }
 void DxilStructAnnotation::SetCBufferSize(unsigned size) { m_CBufferSize = size; }

lib/HLSL/DxilCondenseResources.cpp

@@ -1621,6 +1621,9 @@ StructType *UpdateStructTypeForLegacyLayout(StructType *ST, bool IsCBuf,
     DxilStructAnnotation *NewSA = TypeSys.AddStructAnnotation(NewST);
     // Clone annotation.
     *NewSA = *SA;
+    // Make sure we set the struct type back to the new one, since the
+    // clone would have clobbered it with the old one.
+    NewSA->SetStructType(NewST);
     return NewST;
   }
 }
@@ -1631,7 +1634,7 @@ void UpdateStructTypeForLegacyLayout(DxilResourceBase &Res,
   Type *ElemTy = Symbol->getType()->getPointerElementType();
   bool IsResourceArray = Res.GetRangeSize() != 1;
   if (IsResourceArray) {
-    // Support Array of struct buffer.
+    // Support Array of ConstantBuffer.
     if (ElemTy->isArrayTy())
       ElemTy = ElemTy->getArrayElementType();
   }