[llvm-reduce] Move most debugging output behind --verbose

This should cut down on the visual noise when reducing. Still keep output when we run a pass or when we successfully reduce.

Notably, this also suppresses redirecting the test output to stdout/stderr.

Reviewed By: regehr

Differential Revision: https://reviews.llvm.org/D131922

llvm/tools/llvm-reduce/TestRunner.cpp

@@ -8,7 +8,7 @@
 
 #include "TestRunner.h"
 #include "ReducerWorkItem.h"
-#include "llvm/CodeGen/MachineFunction.h"
+#include "deltas/Utils.h"
 
 using namespace llvm;
 
@@ -33,9 +33,15 @@ int TestRunner::run(StringRef Filename) {
   ProgramArgs.push_back(Filename);
 
   std::string ErrMsg;
-  int Result = sys::ExecuteAndWait(
-      TestName, ProgramArgs, /*Env=*/None, /*Redirects=*/None,
-      /*SecondsToWait=*/0, /*MemoryLimit=*/0, &ErrMsg);
+  SmallVector<Optional<StringRef>, 3> Redirects;
+  Optional<StringRef> Empty = StringRef();
+  if (!Verbose) {
+    for (int i = 0; i < 3; ++i)
+      Redirects.push_back(Empty);
+  }
+  int Result =
+      sys::ExecuteAndWait(TestName, ProgramArgs, /*Env=*/None, Redirects,
+                          /*SecondsToWait=*/0, /*MemoryLimit=*/0, &ErrMsg);
 
   if (Result < 0) {
     Error E = make_error<StringError>("Error running interesting-ness test: " +

llvm/tools/llvm-reduce/deltas/Delta.cpp

@@ -14,9 +14,10 @@
 
 #include "Delta.h"
 #include "ReducerWorkItem.h"
+#include "Utils.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/Analysis/ProfileSummaryInfo.h"
 #include "llvm/Analysis/ModuleSummaryAnalysis.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm/CodeGen/MachineFunction.h"
@@ -118,7 +119,8 @@ static int getLines(StringRef Filepath) {
 /// Splits Chunks in half and prints them.
 /// If unable to split (when chunk size is 1) returns false.
 static bool increaseGranularity(std::vector<Chunk> &Chunks) {
-  errs() << "Increasing granularity...";
+  if (Verbose)
+    errs() << "Increasing granularity...";
   std::vector<Chunk> NewChunks;
   bool SplitOne = false;
 
@@ -134,11 +136,13 @@ static bool increaseGranularity(std::vector<Chunk> &Chunks) {
   }
   if (SplitOne) {
     Chunks = NewChunks;
-    errs() << "Success! New Chunks:\n";
-    for (auto C : Chunks) {
-      errs() << '\t';
-      C.print();
-      errs() << '\n';
+    if (Verbose) {
+      errs() << "Success! New Chunks:\n";
+      for (auto C : Chunks) {
+        errs() << '\t';
+        C.print();
+        errs() << '\n';
+      }
     }
   }
   return SplitOne;
@@ -177,20 +181,26 @@ CheckChunk(Chunk &ChunkToCheckForUninterestingness,
       Clone->print(errs());
       exit(1);
     }
-    errs() << " **** WARNING | reduction resulted in invalid module, "
-              "skipping\n";
+    if (Verbose) {
+      errs() << " **** WARNING | reduction resulted in invalid module, "
+                "skipping\n";
+    }
     return nullptr;
   }
 
-  errs() << "Ignoring: ";
-  ChunkToCheckForUninterestingness.print();
-  for (const Chunk &C : UninterestingChunks)
-    C.print();
+  if (Verbose) {
+    errs() << "Ignoring: ";
+    ChunkToCheckForUninterestingness.print();
+    for (const Chunk &C : UninterestingChunks)
+      C.print();
+    errs() << "\n";
+  }
 
   SmallString<128> CurrentFilepath;
   if (!isReduced(*Clone, Test, CurrentFilepath)) {
     // Program became non-reduced, so this chunk appears to be interesting.
-    errs() << "\n";
+    if (Verbose)
+      errs() << "\n";
     return nullptr;
   }
   return Clone;
@@ -263,7 +273,8 @@ void llvm::runDeltaPass(TestRunner &Test,
 #endif
   }
   if (!Targets) {
-    errs() << "\nNothing to reduce\n";
+    if (Verbose)
+      errs() << "\nNothing to reduce\n";
     return;
   }
 
@@ -382,7 +393,9 @@ void llvm::runDeltaPass(TestRunner &Test,
       FoundAtLeastOneNewUninterestingChunkWithCurrentGranularity = true;
       UninterestingChunks.insert(ChunkToCheckForUninterestingness);
       ReducedProgram = std::move(Result);
-      errs() << " **** SUCCESS | lines: " << getLines(CurrentFilepath) << "\n";
+      if (Verbose)
+        errs() << " **** SUCCESS | lines: " << getLines(CurrentFilepath)
+               << "\n";
       writeOutput(*ReducedProgram, "Saved new best reduction to ");
     }
     // Delete uninteresting chunks
@@ -397,5 +410,6 @@ void llvm::runDeltaPass(TestRunner &Test,
   // If we reduced the testcase replace it
   if (ReducedProgram)
     Test.setProgram(std::move(ReducedProgram));
-  errs() << "Couldn't increase anymore.\n";
+  if (Verbose)
+    errs() << "Couldn't increase anymore.\n";
 }

llvm/tools/llvm-reduce/deltas/Utils.cpp

@@ -16,6 +16,12 @@
 
 using namespace llvm;
 
+extern cl::OptionCategory LLVMReduceOptions;
+
+cl::opt<bool> llvm::Verbose("verbose",
+                            cl::desc("Print extra debugging information"),
+                            cl::init(false), cl::cat(LLVMReduceOptions));
+
 Value *llvm::getDefaultValue(Type *T) {
   return T->isVoidTy() ? PoisonValue::get(T) : Constant::getNullValue(T);
 }

llvm/tools/llvm-reduce/deltas/Utils.h

@@ -15,9 +15,12 @@
 
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Value.h"
+#include "llvm/Support/CommandLine.h"
 
 namespace llvm {
 
+extern cl::opt<bool> Verbose;
+
 Value *getDefaultValue(Type *T);
 bool hasAliasUse(Function &F);