[clang] [clang] Add clang::preferred_type attribute for bitfields (PR #69104)

[Vlad Serebrennikov via cfe-commits]

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@@ -5910,6 +5910,51 @@ static void handleBuiltinAliasAttr(Sema &S, Decl *D,
   D->addAttr(::new (S.Context) BuiltinAliasAttr(S.Context, AL, Ident));
 }
 
+static void handlePreferredTypeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  if (!AL.hasParsedType()) {
+    S.Diag(AL.getLoc(), diag::err_attribute_wrong_number_arguments) << AL << 1;
+    return;
+  }
+
+  TypeSourceInfo *ParmTSI = nullptr;
+  QualType QT = S.GetTypeFromParser(AL.getTypeArg(), &ParmTSI);
+  QT->getAsTagDecl()->setCompleteDefinitionRequired();
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Endilll wrote:

@dwblaikie Would it be fine to do this? The intention here is that we parse type argument of the attribute, and then use it in `CGDebugInfo.h` (you might be interested in changes there as well), bypassing Sema.

https://github.com/llvm/llvm-project/pull/69104