[clang] [clang][dataflow] Fix handling of cyclical data structures in HTMLLogger. (PR #66887)

[Sam McCall via cfe-commits]

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@@ -88,10 +88,12 @@ class ModelDumper {
 
   void dump(Value &V) {
     JOS.attribute("value_id", llvm::to_string(&V));
-    if (!Visited.insert(&V).second)
-      return;
-
     JOS.attribute("kind", debugString(V.getKind()));
+    if (!Visited.insert(&V).second) {
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sam-mccall wrote:

the reordering here looks good, including `kind` is safe & useful

https://github.com/llvm/llvm-project/pull/66887