[llvm] [llvm-profgen] Support creating profiles of arbitrary events (PR #99026)

[via llvm-commits]

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@@ -575,14 +591,54 @@ bool PerfScriptReader::extractLBRStack(TraceStream &TraceIt,
 
   // Skip the leading instruction pointer.
   size_t Index = 0;
+
+  StringRef EventName;
+  // Skip a perf event name. This may or may not exist.
+  if (Records.size() > Index && Records[Index].ends_with(":")) {
+    EventName = Records[Index].ltrim().rtrim(':');
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WenleiHe wrote:

Based on the format in `cmov_3.perfscript`, event name should be extracted from `extractCallstack`, rather than `extractLBRStack`? 

https://github.com/llvm/llvm-project/pull/99026