[clang] [Bounds-Safety] Add sized_by, counted_by_or_null & sized_by_or_null (PR #93231)

[Dan Liew via cfe-commits]

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@@ -8697,9 +8708,10 @@ static bool CheckCountedByAttrOnField(
     InvalidTypeKind = CountedByInvalidPointeeTypeKind::FLEXIBLE_ARRAY_MEMBER;
   }
 
-  if (InvalidTypeKind != CountedByInvalidPointeeTypeKind::VALID) {
+  if (InvalidTypeKind != CountedByInvalidPointeeTypeKind::VALID &&
+      !CountInBytes) {
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delcypher wrote:

I would have thought we would want to prevent `sized_by` on all of the conditions above (e.g. pointee being a function type) apart from pointee being an incomplete type. However, it looks like this implementation allows pointee types for all the cases we disallow it for `counted_by`.

https://github.com/llvm/llvm-project/pull/93231