[llvm-exegesis] Allow lists of BenchmarkResults to be parsed as std::vector<BenchmarkResult>.

llvm-svn: 332221
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
index e906aea..d6b93f4 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
@@ -43,6 +43,7 @@
   std::string Error;
 
   static InstructionBenchmark readYamlOrDie(llvm::StringRef Filename);
+  static std::vector<InstructionBenchmark> readYamlsOrDie(llvm::StringRef Filename);
 
   // Unfortunately this function is non const because of YAML traits.
   void writeYamlOrDie(const llvm::StringRef Filename);