[llvm-mca] Use WithColor for printing errors

[JDevlieghere]

Summary

Use convenience helpers in WithColor to print errors and notes.

[andreadb]

Really cool!

LGTM.

llvm/tools/llvm-mca/llvm-mca.cpp

 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/ToolOutputFile.h"
+#include "llvm/Support/WithColor.h"
 
 using namespace llvm;
 
 static cl::opt<std::string>
     InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
 
 static cl::opt<std::string> OutputFilename("o", cl::desc("Output filename"),
                                            cl::init("-"),
int main(int argc, char **argv) {
 
   // GetTarget() may replaced TripleName with a default triple.
   // For safety, reconstruct the Triple object.
   Triple TheTriple(TripleName);
 
   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
       MemoryBuffer::getFileOrSTDIN(InputFilename);
   if (std::error_code EC = BufferPtr.getError()) {
-    errs() << InputFilename << ": " << EC.message() << '\n';
+    WithColor::error() << InputFilename << ": " << EC.message() << '\n';
     return 1;
   }
 
   SourceMgr SrcMgr;
 
   // Tell SrcMgr about this buffer, which is what the parser will pick up.
   SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
 
int main(int argc, char **argv) {
 
   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
   std::unique_ptr<MCSubtargetInfo> STI(
       TheTarget->createMCSubtargetInfo(TripleName, MCPU, /* FeaturesStr */ ""));
   if (!STI->isCPUStringValid(MCPU))
     return 1;
 
   if (!STI->getSchedModel().isOutOfOrder()) {
-    errs() << "error: please specify an out-of-order cpu. '" << MCPU
+    WithColor::error() << "please specify an out-of-order cpu. '" << MCPU
                        << "' is an in-order cpu.\n";
     return 1;
   }
 
   if (!STI->getSchedModel().hasInstrSchedModel()) {
-    errs()
-        << "error: unable to find instruction-level scheduling information for"
+    WithColor::error()
+        << "unable to find instruction-level scheduling information for"
         << " target triple '" << TheTriple.normalize() << "' and cpu '" << MCPU
         << "'.\n";
 
     if (STI->getSchedModel().InstrItineraries)
-      errs() << "note: cpu '" << MCPU << "' provides itineraries. However, "
-             << "instruction itineraries are currently unsupported.\n";
+      WithColor::note()
+          << "cpu '" << MCPU << "' provides itineraries. However, "
     return 1;
   }
 
   std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
       Triple(TripleName), OutputAsmVariant, *MAI, *MCII, *MRI));
   if (!IP) {
-    errs() << "error: unable to create instruction printer for target triple '"
-           << TheTriple.normalize() << "' with assembly variant "
-           << OutputAsmVariant << ".\n";
+    WithColor::error()
+        << "unable to create instruction printer for target triple '"
     return 1;
   }
 
   std::unique_ptr<MCAsmParser> P(createMCAsmParser(SrcMgr, Ctx, Str, *MAI));
   MCAsmLexer &Lexer = P->getLexer();
   MCACommentConsumer CC(Regions);
   Lexer.setCommentConsumer(&CC);
 
   if (AssembleInput(ProgName, *P, TheTarget, *STI, *MCII, MCOptions))
     return 1;
 
   if (Regions.empty()) {
-    errs() << "error: no assembly instructions found.\n";
+    WithColor::error() << "no assembly instructions found.\n";
     return 1;
   }
 
   // Now initialize the output file.
   auto OF = getOutputStream();
   if (std::error_code EC = OF.getError()) {
-    errs() << EC.message() << '\n';
+    WithColor::error() << EC.message() << '\n';
     return 1;
   }
 
   std::unique_ptr<llvm::ToolOutputFile> TOF = std::move(*OF);
 
   const MCSchedModel &SM = STI->getSchedModel();
 
   unsigned Width = SM.IssueWidth;