[clang-scan-deps] Verbose mode

[jkorous]

Summary

We might print the runtime info only conditionally to make parsing of output tiny bit easier.

[arphaman]

LGTM

[arphaman]

clang/tools/clang-scan-deps/ClangScanDeps.cpp

180

One final comment, can you add a category DependencyScannerCategory for this option?

clang/tools/clang-scan-deps/ClangScanDeps.cpp

 llvm::cl::opt<bool> SkipExcludedPPRanges(
     "skip-excluded-pp-ranges",
     llvm::cl::desc(
         "Use the preprocessor optimization that skips excluded conditionals by "
         "bumping the buffer pointer in the lexer instead of lexing the tokens  "
         "until reaching the end directive."),
     llvm::cl::init(true), llvm::cl::cat(DependencyScannerCategory));
 
+llvm::cl::opt<bool> Verbose("v", llvm::cl::Optional,
+                            llvm::cl::desc("Use verbose output."),
+                            llvm::cl::init(false),
+                            llvm::cl::cat(DependencyScannerCategory));
+
 } // end anonymous namespace
 
 /// \returns object-file path derived from source-file path.
 static std::string getObjFilePath(StringRef SrcFile) {
   SmallString<128> ObjFileName(SrcFile);
   llvm::sys::path::replace_extension(ObjFileName, "o");
   return ObjFileName.str();
 }
for (unsigned I = 0; I < NumWorkers; ++I)
     WorkerTools.push_back(std::make_unique<DependencyScanningTool>(
         Service, *AdjustingCompilations, DependencyOS, Errs));
 
   std::vector<std::thread> WorkerThreads;
   std::atomic<bool> HadErrors(false);
   std::mutex Lock;
   size_t Index = 0;
 
+  if (Verbose) {
     llvm::outs() << "Running clang-scan-deps on " << Inputs.size()
                  << " files using " << NumWorkers << " workers\n";
+  }
   for (unsigned I = 0; I < NumWorkers; ++I) {
     auto Worker = [I, &Lock, &Index, &Inputs, &HadErrors, &WorkerTools]() {
       while (true) {
         std::string Input;
         StringRef CWD;
         // Take the next input.
         {
           std::unique_lock<std::mutex> LockGuard(Lock);