Add llvm-exegesis tool.

Summary:
[llvm-exegesis][RFC] Automatic Measurement of Instruction Latency/Uops

This is the code corresponding to the RFC "llvm-exegesis Automatic Measurement of Instruction Latency/Uops".

The RFC is available on the LLVM mailing lists as well as the following document
for easier reading:
https://docs.google.com/document/d/1QidaJMJUyQdRrFKD66vE1_N55whe0coQ3h1GpFzz27M/edit?usp=sharing

Subscribers: mgorny, gchatelet, orwant, llvm-commits

Differential Revision: https://reviews.llvm.org/D44519

llvm-svn: 329156

1 files changed, 53 insertions, 0 deletions

diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
new file mode 100644
index 00000000000..6c238fd1484
--- /dev/null
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
@@ -0,0 +1,53 @@
+//===-- BenchmarkResult.h ---------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Defines classes to represent measurements and serialize/deserialize them to
+//  Yaml.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_EXEGESIS_BENCHMARKRESULT_H
+#define LLVM_TOOLS_LLVM_EXEGESIS_BENCHMARKRESULT_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/YAMLTraits.h"
+#include <string>
+#include <vector>
+
+namespace exegesis {
+
+struct AsmTemplate {
+  std::string Name;
+};
+
+struct BenchmarkMeasure {
+  std::string Key;
+  double Value;
+  std::string DebugString;
+};
+
+// The result of an instruction benchmark.
+struct InstructionBenchmark {
+  AsmTemplate AsmTmpl;
+  std::string CpuName;
+  std::string LLVMTriple;
+  size_t NumRepetitions = 0;
+  std::vector<BenchmarkMeasure> Measurements;
+  std::string Error;
+
+  static InstructionBenchmark readYamlOrDie(llvm::StringRef Filename);
+
+  // Unfortunately this function is non const because of YAML traits.
+  void writeYamlOrDie(const llvm::StringRef Filename);
+};
+
+} // namespace exegesis
+
+#endif // LLVM_TOOLS_LLVM_EXEGESIS_BENCHMARKRESULT_H