[llvm] [Sample Profile Loader] Fix potential invalidated reference (PR #73181)

[via llvm-commits]

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@@ -205,8 +208,9 @@ class ProfiledCallGraph {
   }
 
   ProfiledCallGraphNode Root;
-  HashKeyMap<std::unordered_map, FunctionId, ProfiledCallGraphNode>
-      ProfiledFunctions;
+  // backing buffer for ProfiledCallGraphNodes.
+  std::list<ProfiledCallGraphNode> ProfiledCallGraphNodeList;
+  llvm::DenseMap<FunctionId, ProfiledCallGraphNode*> ProfiledFunctions;
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WenleiHe wrote:

Why moving away from `HashKeyMap`? Don't you still want the unification between MD5 and string name in this case? 



https://github.com/llvm/llvm-project/pull/73181