From 446268a223452254e054714f252705858fc47563 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Milo=C5=A1=20Stojanovi=C4=87?= <Milos.Stojanovic@rt-rk.com>
Date: Thu, 6 Feb 2020 17:08:05 +0100
Subject: [PATCH] [llvm-exegesis] Add a custom error for clustering

All errors of type `Failure` are `StringError`s. In order for exit code
mapping to detect that specifically a clustering error has occurred it
needs to have a different type.

This patch also prepares D74085 where termination `report_fatal_error()`
will be replaced with emitting `StringError`s.

Differential Revision: https://reviews.llvm.org/D74124
---
 llvm/tools/llvm-exegesis/lib/CMakeLists.txt |  1 +
 llvm/tools/llvm-exegesis/lib/Clustering.cpp | 12 ++++++------
 llvm/tools/llvm-exegesis/lib/Error.cpp      | 25 +++++++++++++++++++++++++
 llvm/tools/llvm-exegesis/lib/Error.h        | 13 +++++++++++++
 llvm/tools/llvm-exegesis/llvm-exegesis.cpp  |  2 +-
 5 files changed, 46 insertions(+), 7 deletions(-)
 create mode 100644 llvm/tools/llvm-exegesis/lib/Error.cpp

diff --git a/llvm/tools/llvm-exegesis/lib/CMakeLists.txt b/llvm/tools/llvm-exegesis/lib/CMakeLists.txt
index aa11d54..a839874 100644
--- a/llvm/tools/llvm-exegesis/lib/CMakeLists.txt
+++ b/llvm/tools/llvm-exegesis/lib/CMakeLists.txt
@@ -27,6 +27,7 @@ add_library(LLVMExegesis
   BenchmarkRunner.cpp
   Clustering.cpp
   CodeTemplate.cpp
+  Error.cpp
   LatencyBenchmarkRunner.cpp
   LlvmState.cpp
   MCInstrDescView.cpp
diff --git a/llvm/tools/llvm-exegesis/lib/Clustering.cpp b/llvm/tools/llvm-exegesis/lib/Clustering.cpp
index 95d5cfb..33a8e01 100644
--- a/llvm/tools/llvm-exegesis/lib/Clustering.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Clustering.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Clustering.h"
+#include "Error.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
@@ -106,14 +107,13 @@ Error InstructionBenchmarkClustering::validateAndSetup() {
     const auto *CurMeasurement = &Point.Measurements;
     if (LastMeasurement) {
       if (LastMeasurement->size() != CurMeasurement->size()) {
-        return make_error<StringError>("inconsistent measurement dimensions",
-                                       inconvertibleErrorCode());
+        return make_error<ClusteringError>(
+            "inconsistent measurement dimensions");
       }
       for (size_t I = 0, E = LastMeasurement->size(); I < E; ++I) {
         if (LastMeasurement->at(I).Key != CurMeasurement->at(I).Key) {
-          return make_error<StringError>(
-              "inconsistent measurement dimensions keys",
-              inconvertibleErrorCode());
+          return make_error<ClusteringError>(
+              "inconsistent measurement dimensions keys");
         }
       }
     }
@@ -333,7 +333,7 @@ Expected<InstructionBenchmarkClustering> InstructionBenchmarkClustering::create(
       Clustering.stabilize(NumOpcodes.getValue());
   } else /*if(Mode == ModeE::Naive)*/ {
     if (!NumOpcodes.hasValue())
-      report_fatal_error(
+      return make_error<Failure>(
           "'naive' clustering mode requires opcode count to be specified");
     Clustering.clusterizeNaive(NumOpcodes.getValue());
   }
diff --git a/llvm/tools/llvm-exegesis/lib/Error.cpp b/llvm/tools/llvm-exegesis/lib/Error.cpp
new file mode 100644
index 0000000..d8aaf78
--- /dev/null
+++ b/llvm/tools/llvm-exegesis/lib/Error.cpp
@@ -0,0 +1,25 @@
+//===-- Error.cpp -----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Error.h"
+
+namespace llvm {
+namespace exegesis {
+
+char ClusteringError::ID;
+
+void ClusteringError::log(raw_ostream &OS) const {
+  OS << Msg;
+}
+
+std::error_code ClusteringError::convertToErrorCode() const {
+  return inconvertibleErrorCode();
+}
+
+} // namespace exegesis
+} // namespace llvm
diff --git a/llvm/tools/llvm-exegesis/lib/Error.h b/llvm/tools/llvm-exegesis/lib/Error.h
index 720cc68..dc203c8 100644
--- a/llvm/tools/llvm-exegesis/lib/Error.h
+++ b/llvm/tools/llvm-exegesis/lib/Error.h
@@ -22,6 +22,19 @@ public:
   Failure(const Twine &S) : StringError(S, inconvertibleErrorCode()) {}
 };
 
+// A class representing failures that happened during clustering calculations.
+class ClusteringError : public ErrorInfo<ClusteringError> {
+public:
+  static char ID;
+  ClusteringError(const Twine&S) : Msg(S.str()) {}
+
+  void log(raw_ostream &OS) const override;
+
+  std::error_code convertToErrorCode() const override;
+private:
+    std::string Msg;
+};
+
 } // namespace exegesis
 } // namespace llvm
 
diff --git a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
index c4574d3..a3670d5 100644
--- a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
+++ b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
@@ -373,7 +373,7 @@ int main(int Argc, char **Argv) {
   cl::ParseCommandLineOptions(Argc, Argv, "");
 
   exegesis::ExitOnErr.setExitCodeMapper([](const Error &Err) {
-    if (Err.isA<StringError>())
+    if (Err.isA<exegesis::ClusteringError>())
       return EXIT_SUCCESS;
     return EXIT_FAILURE;
   });
-- 
2.7.4