[llvm] [rtsan] Handle attributed IR function declarations (PR #169577)

[Chris Apple via llvm-commits]

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@@ -61,23 +61,21 @@ static void insertCallAtAllFunctionExitPoints(Function &Fn,
       insertCallBeforeInstruction(Fn, I, InsertFnName, FunctionArgs);
 }
 
-static PreservedAnalyses rtsanPreservedCFGAnalyses() {
-  PreservedAnalyses PA;
-  PA.preserveSet<CFGAnalyses>();
-  return PA;
-}
+static void runSanitizeRealtime(Function &Fn) {
+  if (Fn.empty())
+    return;
 
-static PreservedAnalyses runSanitizeRealtime(Function &Fn) {
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cjappl wrote:

Is not returning these preserved analyses going to bite us elsewhere? I remember most of the sanitizer transform passes (or transform passes generally) returning these.

https://github.com/llvm/llvm-project/pull/169577