[llvm] [Bolt] Add a new hidden option to perf2bolt for testing purpose (PR #163785)

[Amir Ayupov via llvm-commits]

================
@@ -372,6 +379,80 @@ void DataAggregator::parsePreAggregated() {
   }
 }
 
+bool DataAggregator::isMMapEvent(StringRef Line) {
+  // Short cut to avoid string find is possible.
+  if (Line.empty() || Line.size() < 50)
+    return false;
+
----------------
aaupov wrote:

Where does the number 50 come from? How much overhead is added if we remove these shortcuts?

https://github.com/llvm/llvm-project/pull/163785