[clang] [lldb] [Clang] Improve Sema diagnostic performance for __builtin_counted_by_ref (PR #116719)

[via cfe-commits]

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@@ -14690,6 +14690,13 @@ void Sema::FinalizeDeclaration(Decl *ThisDecl) {
     }
   }
 
+  // The result of __builtin_counted_by_ref cannot be assigned to a variable.
+  // It allows leaking and modification of bounds safety information.
+  if (IsBuiltinCountedByRef(VD->getInit()))
+    Diag(VD->getInit()->getExprLoc(),
+         diag::err_builtin_counted_by_ref_cannot_leak_reference)
+        << VD->getInit()->getSourceRange();
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Sirraide wrote:

I was going to comment on that too, but ended up forgetting about it; it’s used in like 3–4 places, so I personally would prefer making this a helper function.

https://github.com/llvm/llvm-project/pull/116719