[clang] [BoundsSafety][NFC] Add the count-refill logic for late-parsed bounds attributes (PR #224556)

[Yeoul Na via cfe-commits]

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@@ -4896,6 +4896,54 @@ void Parser::ParseLexedTypeAttribute(LateParsedTypeAttribute &LA,
   OutAttrs.takeAllAppendingFrom(Attrs);
 }
 
+void Parser::CompleteLateParsedTypeAttributes(
+    SmallVectorImpl<LateParsedTypeAttribute *> &LateTypeAttrs) {
+  for (LateParsedTypeAttribute *LTA : LateTypeAttrs) {
+    // Read these out before parsing, which destroys the attribute. The type is
+    // null if construction rejected the attribute, in which case the diagnostic
+    // has already been emitted and there is nothing to complete.
+    BoundsAttributedType *BATy = LTA->TypeToComplete;
+    // Rejected during construction (already diagnosed); the cached tokens are
+    // self-contained, so there is nothing to drain — just discard it.
+    if (!BATy) {
+      delete LTA;
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rapidsna wrote:

I used `unique_ptr` and removed raw `delete`s in this function for the sake of this PR. Will file a separate issue to track the ownership issue for the whole LateParsedDeclaration family.

https://github.com/llvm/llvm-project/pull/224556