[llvm-exegesis] Don't default to running&dumping all analyses to '-'

Summary:
Up until the point i have looked in the source, i didn't even understood that
i can disable 'cluster' output. I have always silenced it via ` &> /dev/null`.
(And hoped it wasn't contributing much of the run time.)

While i expect that it has it's use-cases i never once needed it so far.
If i forget to silence it, console is completely flooded with that output.

How about not expecting users to opt-out of analyses,
but to explicitly specify the analyses that should be performed?

Reviewers: courbet, gchatelet

Reviewed By: courbet

Subscribers: tschuett, RKSimon, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57648

llvm-svn: 353021

1 files changed, 9 insertions, 2 deletions

diff --git a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
index ce11fadbf6e..55903728f9d 100644
--- a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
+++ b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
@@ -91,10 +91,10 @@ static cl::opt<float>
 
 static cl::opt<std::string>
     AnalysisClustersOutputFile("analysis-clusters-output-file", cl::desc(""),
-                               cl::init("-"));
+                               cl::init(""));
 static cl::opt<std::string>
     AnalysisInconsistenciesOutputFile("analysis-inconsistencies-output-file",
-                                      cl::desc(""), cl::init("-"));
+                                      cl::desc(""), cl::init(""));
 
 static cl::opt<std::string>
     CpuName("mcpu",
@@ -404,6 +404,13 @@ static void analysisMain() {
   if (BenchmarkFile.empty())
     llvm::report_fatal_error("--benchmarks-file must be set.");
 
+  if (AnalysisClustersOutputFile.empty() &&
+      AnalysisInconsistenciesOutputFile.empty()) {
+    llvm::report_fatal_error(
+        "At least one of --analysis-clusters-output-file and "
+        "--analysis-inconsistencies-output-file must be specified.");
+  }
+
   llvm::InitializeNativeTarget();
   llvm::InitializeNativeTargetAsmPrinter();
   llvm::InitializeNativeTargetDisassembler();