[llvm-exegesis] Get rid of debug_string.

Summary:
THis is a backwards-compatible change (existing files will work as
expected).

See PR39082.

Reviewers: gchatelet

Subscribers: tschuett, llvm-commits

Differential Revision: https://reviews.llvm.org/D52546

llvm-svn: 343108
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
index 0fcf4e9..961c07b 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
@@ -43,7 +43,7 @@
 struct BenchmarkMeasure {
   // A helper to create an unscaled BenchmarkMeasure.
   static BenchmarkMeasure Create(std::string Key, double Value) {
-    return {Key, Value, Value, Key};
+    return {Key, Value, Value};
   }
   std::string Key;
   // This is the per-instruction value, i.e. measured quantity scaled per
@@ -52,8 +52,6 @@
   // This is the per-snippet value, i.e. measured quantity for one repetition of
   // the whole snippet.
   double PerSnippetValue;
-  // FIXME: remove, use `Key` instead.
-  std::string DebugString;
 };
 
 // The result of an instruction benchmark.