[clang] [HLSL] Constant buffer layout struct update (PR #124840)

[Helena Kotas via cfe-commits]

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@@ -393,7 +396,7 @@ static FieldDecl *createFieldForHostLayoutStruct(Sema &S, const Type *Ty,
   auto *Field = FieldDecl::Create(AST, LayoutStruct, SourceLocation(),
                                   SourceLocation(), II, QT, TSI, nullptr, false,
                                   InClassInitStyle::ICIS_NoInit);
-  Field->setAccess(AccessSpecifier::AS_private);
+  Field->setAccess(AccessSpecifier::AS_public);
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hekota wrote:

It should be public so the layout struct can qualify as POD (plain old data), which affects the LLVM memory layout. It prevents LLVM from adding padding between the members or after the struct.

https://github.com/llvm/llvm-project/pull/124840