[clang] [CIR] Add support for constructors with VTT parameters (PR #156521)

[Henrich Lauko via cfe-commits]

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@@ -549,3 +652,32 @@ bool CIRGenItaniumCXXABI::isVirtualOffsetNeededForVTableField(
     return false;
   return needsVTTParameter(cgf.curGD);
 }
+
+mlir::Value CIRGenItaniumCXXABI::getVirtualBaseClassOffset(
+    mlir::Location loc, CIRGenFunction &cgf, Address thisAddr,
+    const CXXRecordDecl *classDecl, const CXXRecordDecl *baseClassDecl) {
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xlauko wrote:

Maybe add `CIRGenBuilderTy &builder = cgf.getBuilder();` as it is used at many places here and use `builder` instead. 

https://github.com/llvm/llvm-project/pull/156521