tools/llvm-mca/llvm-mca.cpp

   1 //===-- llvm-mca.cpp - Machine Code Analyzer -------------------*- C++ -* -===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This utility is a simple driver that allows static performance analysis on
  10 // machine code similarly to how IACA (Intel Architecture Code Analyzer) works.
  11 //
  12 //   llvm-mca [options] <file-name>
  13 //      -march <type>
  14 //      -mcpu <cpu>
  15 //      -o <file>
  16 //
  17 // The target defaults to the host target.
  18 // The cpu defaults to the 'native' host cpu.
  19 // The output defaults to standard output.
  20 //
  21 //===----------------------------------------------------------------------===//
  22
  23 #include "CodeRegion.h"
  24 #include "CodeRegionGenerator.h"
  25 #include "PipelinePrinter.h"
  26 #include "Views/BottleneckAnalysis.h"
  27 #include "Views/DispatchStatistics.h"
  28 #include "Views/InstructionInfoView.h"
  29 #include "Views/RegisterFileStatistics.h"
  30 #include "Views/ResourcePressureView.h"
  31 #include "Views/RetireControlUnitStatistics.h"
  32 #include "Views/SchedulerStatistics.h"
  33 #include "Views/SummaryView.h"
  34 #include "Views/TimelineView.h"
  35 #include "llvm/MC/MCAsmInfo.h"
  36 #include "llvm/MC/MCContext.h"
  37 #include "llvm/MC/MCObjectFileInfo.h"
  38 #include "llvm/MC/MCRegisterInfo.h"
  39 #include "llvm/MCA/Context.h"
  40 #include "llvm/MCA/Pipeline.h"
  41 #include "llvm/MCA/Stages/EntryStage.h"
  42 #include "llvm/MCA/Stages/InstructionTables.h"
  43 #include "llvm/MCA/Support.h"
  44 #include "llvm/Support/CommandLine.h"
  45 #include "llvm/Support/ErrorHandling.h"
  46 #include "llvm/Support/ErrorOr.h"
  47 #include "llvm/Support/FileSystem.h"
  48 #include "llvm/Support/Host.h"
  49 #include "llvm/Support/InitLLVM.h"
  50 #include "llvm/Support/MemoryBuffer.h"
  51 #include "llvm/Support/SourceMgr.h"
  52 #include "llvm/Support/TargetRegistry.h"
  53 #include "llvm/Support/TargetSelect.h"
  54 #include "llvm/Support/ToolOutputFile.h"
  55 #include "llvm/Support/WithColor.h"
  56
  57 using namespace llvm;
  58
  59 static cl::OptionCategory ToolOptions("Tool Options");
  60 static cl::OptionCategory ViewOptions("View Options");
  61
  62 static cl::opt<std::string> InputFilename(cl::Positional,
  63                                           cl::desc("<input file>"),
  64                                           cl::cat(ToolOptions), cl::init("-"));
  65
  66 static cl::opt<std::string> OutputFilename("o", cl::desc("Output filename"),
  67                                            cl::init("-"), cl::cat(ToolOptions),
  68                                            cl::value_desc("filename"));
  69
  70 static cl::opt<std::string>
  71     ArchName("march",
  72              cl::desc("Target architecture. "
  73                       "See -version for available targets"),
  74              cl::cat(ToolOptions));
  75
  76 static cl::opt<std::string>
  77     TripleName("mtriple",
  78                cl::desc("Target triple. See -version for available targets"),
  79                cl::cat(ToolOptions));
  80
  81 static cl::opt<std::string>
  82     MCPU("mcpu",
  83          cl::desc("Target a specific cpu type (-mcpu=help for details)"),
  84          cl::value_desc("cpu-name"), cl::cat(ToolOptions), cl::init("native"));
  85
  86 static cl::opt<int>
  87     OutputAsmVariant("output-asm-variant",
  88                      cl::desc("Syntax variant to use for output printing"),
  89                      cl::cat(ToolOptions), cl::init(-1));
  90
  91 static cl::opt<bool>
  92     PrintImmHex("print-imm-hex", cl::cat(ToolOptions), cl::init(false),
  93                 cl::desc("Prefer hex format when printing immediate values"));
  94
  95 static cl::opt<unsigned> Iterations("iterations",
  96                                     cl::desc("Number of iterations to run"),
  97                                     cl::cat(ToolOptions), cl::init(0));
  98
  99 static cl::opt<unsigned>
 100     DispatchWidth("dispatch", cl::desc("Override the processor dispatch width"),
 101                   cl::cat(ToolOptions), cl::init(0));
 102
 103 static cl::opt<unsigned>
 104     RegisterFileSize("register-file-size",
 105                      cl::desc("Maximum number of physical registers which can "
 106                               "be used for register mappings"),
 107                      cl::cat(ToolOptions), cl::init(0));
 108
 109 static cl::opt<unsigned>
 110     MicroOpQueue("micro-op-queue-size", cl::Hidden,
 111                  cl::desc("Number of entries in the micro-op queue"),
 112                  cl::cat(ToolOptions), cl::init(0));
 113
 114 static cl::opt<unsigned>
 115     DecoderThroughput("decoder-throughput", cl::Hidden,
 116                       cl::desc("Maximum throughput from the decoders "
 117                                "(instructions per cycle)"),
 118                       cl::cat(ToolOptions), cl::init(0));
 119
 120 static cl::opt<bool>
 121     PrintRegisterFileStats("register-file-stats",
 122                            cl::desc("Print register file statistics"),
 123                            cl::cat(ViewOptions), cl::init(false));
 124
 125 static cl::opt<bool> PrintDispatchStats("dispatch-stats",
 126                                         cl::desc("Print dispatch statistics"),
 127                                         cl::cat(ViewOptions), cl::init(false));
 128
 129 static cl::opt<bool>
 130     PrintSummaryView("summary-view", cl::Hidden,
 131                      cl::desc("Print summary view (enabled by default)"),
 132                      cl::cat(ViewOptions), cl::init(true));
 133
 134 static cl::opt<bool> PrintSchedulerStats("scheduler-stats",
 135                                          cl::desc("Print scheduler statistics"),
 136                                          cl::cat(ViewOptions), cl::init(false));
 137
 138 static cl::opt<bool>
 139     PrintRetireStats("retire-stats",
 140                      cl::desc("Print retire control unit statistics"),
 141                      cl::cat(ViewOptions), cl::init(false));
 142
 143 static cl::opt<bool> PrintResourcePressureView(
 144     "resource-pressure",
 145     cl::desc("Print the resource pressure view (enabled by default)"),
 146     cl::cat(ViewOptions), cl::init(true));
 147
 148 static cl::opt<bool> PrintTimelineView("timeline",
 149                                        cl::desc("Print the timeline view"),
 150                                        cl::cat(ViewOptions), cl::init(false));
 151
 152 static cl::opt<unsigned> TimelineMaxIterations(
 153     "timeline-max-iterations",
 154     cl::desc("Maximum number of iterations to print in timeline view"),
 155     cl::cat(ViewOptions), cl::init(0));
 156
 157 static cl::opt<unsigned> TimelineMaxCycles(
 158     "timeline-max-cycles",
 159     cl::desc(
 160         "Maximum number of cycles in the timeline view. Defaults to 80 cycles"),
 161     cl::cat(ViewOptions), cl::init(80));
 162
 163 static cl::opt<bool>
 164     AssumeNoAlias("noalias",
 165                   cl::desc("If set, assume that loads and stores do not alias"),
 166                   cl::cat(ToolOptions), cl::init(true));
 167
 168 static cl::opt<unsigned> LoadQueueSize("lqueue",
 169                                        cl::desc("Size of the load queue"),
 170                                        cl::cat(ToolOptions), cl::init(0));
 171
 172 static cl::opt<unsigned> StoreQueueSize("squeue",
 173                                         cl::desc("Size of the store queue"),
 174                                         cl::cat(ToolOptions), cl::init(0));
 175
 176 static cl::opt<bool>
 177     PrintInstructionTables("instruction-tables",
 178                            cl::desc("Print instruction tables"),
 179                            cl::cat(ToolOptions), cl::init(false));
 180
 181 static cl::opt<bool> PrintInstructionInfoView(
 182     "instruction-info",
 183     cl::desc("Print the instruction info view (enabled by default)"),
 184     cl::cat(ViewOptions), cl::init(true));
 185
 186 static cl::opt<bool> EnableAllStats("all-stats",
 187                                     cl::desc("Print all hardware statistics"),
 188                                     cl::cat(ViewOptions), cl::init(false));
 189
 190 static cl::opt<bool>
 191     EnableAllViews("all-views",
 192                    cl::desc("Print all views including hardware statistics"),
 193                    cl::cat(ViewOptions), cl::init(false));
 194
 195 static cl::opt<bool> EnableBottleneckAnalysis(
 196     "bottleneck-analysis",
 197     cl::desc("Enable bottleneck analysis (disabled by default)"),
 198     cl::cat(ViewOptions), cl::init(false));
 199
 200 namespace {
 201
 202 const Target *getTarget(const char *ProgName) {
 203   if (TripleName.empty())
 204     TripleName = Triple::normalize(sys::getDefaultTargetTriple());
 205   Triple TheTriple(TripleName);
 206
 207   // Get the target specific parser.
 208   std::string Error;
 209   const Target *TheTarget =
 210       TargetRegistry::lookupTarget(ArchName, TheTriple, Error);
 211   if (!TheTarget) {
 212     errs() << ProgName << ": " << Error;
 213     return nullptr;
 214   }
 215
 216   // Return the found target.
 217   return TheTarget;
 218 }
 219
 220 ErrorOr<std::unique_ptr<ToolOutputFile>> getOutputStream() {
 221   if (OutputFilename == "")
 222     OutputFilename = "-";
 223   std::error_code EC;
 224   auto Out =
 225       llvm::make_unique<ToolOutputFile>(OutputFilename, EC, sys::fs::OF_None);
 226   if (!EC)
 227     return std::move(Out);
 228   return EC;
 229 }
 230 } // end of anonymous namespace
 231
 232 static void processOptionImpl(cl::opt<bool> &O, const cl::opt<bool> &Default) {
 233   if (!O.getNumOccurrences() || O.getPosition() < Default.getPosition())
 234     O = Default.getValue();
 235 }
 236
 237 static void processViewOptions() {
 238   if (!EnableAllViews.getNumOccurrences() &&
 239       !EnableAllStats.getNumOccurrences())
 240     return;
 241
 242   if (EnableAllViews.getNumOccurrences()) {
 243     processOptionImpl(PrintSummaryView, EnableAllViews);
 244     processOptionImpl(EnableBottleneckAnalysis, EnableAllViews);
 245     processOptionImpl(PrintResourcePressureView, EnableAllViews);
 246     processOptionImpl(PrintTimelineView, EnableAllViews);
 247     processOptionImpl(PrintInstructionInfoView, EnableAllViews);
 248   }
 249
 250   const cl::opt<bool> &Default =
 251       EnableAllViews.getPosition() < EnableAllStats.getPosition()
 252           ? EnableAllStats
 253           : EnableAllViews;
 254   processOptionImpl(PrintRegisterFileStats, Default);
 255   processOptionImpl(PrintDispatchStats, Default);
 256   processOptionImpl(PrintSchedulerStats, Default);
 257   processOptionImpl(PrintRetireStats, Default);
 258 }
 259
 260 // Returns true on success.
 261 static bool runPipeline(mca::Pipeline &P) {
 262   // Handle pipeline errors here.
 263   Expected<unsigned> Cycles = P.run();
 264   if (!Cycles) {
 265     WithColor::error() << toString(Cycles.takeError());
 266     return false;
 267   }
 268   return true;
 269 }
 270
 271 int main(int argc, char **argv) {
 272   InitLLVM X(argc, argv);
 273
 274   // Initialize targets and assembly parsers.
 275   InitializeAllTargetInfos();
 276   InitializeAllTargetMCs();
 277   InitializeAllAsmParsers();
 278
 279   // Enable printing of available targets when flag --version is specified.
 280   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
 281
 282   cl::HideUnrelatedOptions({&ToolOptions, &ViewOptions});
 283
 284   // Parse flags and initialize target options.
 285   cl::ParseCommandLineOptions(argc, argv,
 286                               "llvm machine code performance analyzer.\n");
 287
 288   // Get the target from the triple. If a triple is not specified, then select
 289   // the default triple for the host. If the triple doesn't correspond to any
 290   // registered target, then exit with an error message.
 291   const char *ProgName = argv[0];
 292   const Target *TheTarget = getTarget(ProgName);
 293   if (!TheTarget)
 294     return 1;
 295
 296   // GetTarget() may replaced TripleName with a default triple.
 297   // For safety, reconstruct the Triple object.
 298   Triple TheTriple(TripleName);
 299
 300   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
 301       MemoryBuffer::getFileOrSTDIN(InputFilename);
 302   if (std::error_code EC = BufferPtr.getError()) {
 303     WithColor::error() << InputFilename << ": " << EC.message() << '\n';
 304     return 1;
 305   }
 306
 307   // Apply overrides to llvm-mca specific options.
 308   processViewOptions();
 309
 310   SourceMgr SrcMgr;
 311
 312   // Tell SrcMgr about this buffer, which is what the parser will pick up.
 313   SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
 314
 315   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
 316   assert(MRI && "Unable to create target register info!");
 317
 318   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
 319   assert(MAI && "Unable to create target asm info!");
 320
 321   MCObjectFileInfo MOFI;
 322   MCContext Ctx(MAI.get(), MRI.get(), &MOFI, &SrcMgr);
 323   MOFI.InitMCObjectFileInfo(TheTriple, /* PIC= */ false, Ctx);
 324
 325   std::unique_ptr<buffer_ostream> BOS;
 326
 327   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
 328
 329   std::unique_ptr<MCInstrAnalysis> MCIA(
 330       TheTarget->createMCInstrAnalysis(MCII.get()));
 331
 332   if (!MCPU.compare("native"))
 333     MCPU = llvm::sys::getHostCPUName();
 334
 335   std::unique_ptr<MCSubtargetInfo> STI(
 336       TheTarget->createMCSubtargetInfo(TripleName, MCPU, /* FeaturesStr */ ""));
 337   if (!STI->isCPUStringValid(MCPU))
 338     return 1;
 339
 340   if (!PrintInstructionTables && !STI->getSchedModel().isOutOfOrder()) {
 341     WithColor::error() << "please specify an out-of-order cpu. '" << MCPU
 342                        << "' is an in-order cpu.\n";
 343     return 1;
 344   }
 345
 346   if (!STI->getSchedModel().hasInstrSchedModel()) {
 347     WithColor::error()
 348         << "unable to find instruction-level scheduling information for"
 349         << " target triple '" << TheTriple.normalize() << "' and cpu '" << MCPU
 350         << "'.\n";
 351
 352     if (STI->getSchedModel().InstrItineraries)
 353       WithColor::note()
 354           << "cpu '" << MCPU << "' provides itineraries. However, "
 355           << "instruction itineraries are currently unsupported.\n";
 356     return 1;
 357   }
 358
 359   // Parse the input and create CodeRegions that llvm-mca can analyze.
 360   mca::AsmCodeRegionGenerator CRG(*TheTarget, SrcMgr, Ctx, *MAI, *STI, *MCII);
 361   Expected<const mca::CodeRegions &> RegionsOrErr = CRG.parseCodeRegions();
 362   if (!RegionsOrErr) {
 363     if (auto Err =
 364             handleErrors(RegionsOrErr.takeError(), [](const StringError &E) {
 365               WithColor::error() << E.getMessage() << '\n';
 366             })) {
 367       // Default case.
 368       WithColor::error() << toString(std::move(Err)) << '\n';
 369     }
 370     return 1;
 371   }
 372   const mca::CodeRegions &Regions = *RegionsOrErr;
 373
 374   // Early exit if errors were found by the code region parsing logic.
 375   if (!Regions.isValid())
 376     return 1;
 377
 378   if (Regions.empty()) {
 379     WithColor::error() << "no assembly instructions found.\n";
 380     return 1;
 381   }
 382
 383   // Now initialize the output file.
 384   auto OF = getOutputStream();
 385   if (std::error_code EC = OF.getError()) {
 386     WithColor::error() << EC.message() << '\n';
 387     return 1;
 388   }
 389
 390   unsigned AssemblerDialect = CRG.getAssemblerDialect();
 391   if (OutputAsmVariant >= 0)
 392     AssemblerDialect = static_cast<unsigned>(OutputAsmVariant);
 393   std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
 394       Triple(TripleName), AssemblerDialect, *MAI, *MCII, *MRI));
 395   if (!IP) {
 396     WithColor::error()
 397         << "unable to create instruction printer for target triple '"
 398         << TheTriple.normalize() << "' with assembly variant "
 399         << AssemblerDialect << ".\n";
 400     return 1;
 401   }
 402
 403   // Set the display preference for hex vs. decimal immediates.
 404   IP->setPrintImmHex(PrintImmHex);
 405
 406   std::unique_ptr<ToolOutputFile> TOF = std::move(*OF);
 407
 408   const MCSchedModel &SM = STI->getSchedModel();
 409
 410   // Create an instruction builder.
 411   mca::InstrBuilder IB(*STI, *MCII, *MRI, MCIA.get());
 412
 413   // Create a context to control ownership of the pipeline hardware.
 414   mca::Context MCA(*MRI, *STI);
 415
 416   mca::PipelineOptions PO(MicroOpQueue, DecoderThroughput, DispatchWidth,
 417                           RegisterFileSize, LoadQueueSize, StoreQueueSize,
 418                           AssumeNoAlias, EnableBottleneckAnalysis);
 419
 420   // Number each region in the sequence.
 421   unsigned RegionIdx = 0;
 422
 423   for (const std::unique_ptr<mca::CodeRegion> &Region : Regions) {
 424     // Skip empty code regions.
 425     if (Region->empty())
 426       continue;
 427
 428     // Don't print the header of this region if it is the default region, and
 429     // it doesn't have an end location.
 430     if (Region->startLoc().isValid() || Region->endLoc().isValid()) {
 431       TOF->os() << "\n[" << RegionIdx++ << "] Code Region";
 432       StringRef Desc = Region->getDescription();
 433       if (!Desc.empty())
 434         TOF->os() << " - " << Desc;
 435       TOF->os() << "\n\n";
 436     }
 437
 438     // Lower the MCInst sequence into an mca::Instruction sequence.
 439     ArrayRef<MCInst> Insts = Region->getInstructions();
 440     std::vector<std::unique_ptr<mca::Instruction>> LoweredSequence;
 441     for (const MCInst &MCI : Insts) {
 442       Expected<std::unique_ptr<mca::Instruction>> Inst =
 443           IB.createInstruction(MCI);
 444       if (!Inst) {
 445         if (auto NewE = handleErrors(
 446                 Inst.takeError(),
 447                 [&IP, &STI](const mca::InstructionError<MCInst> &IE) {
 448                   std::string InstructionStr;
 449                   raw_string_ostream SS(InstructionStr);
 450                   WithColor::error() << IE.Message << '\n';
 451                   IP->printInst(&IE.Inst, SS, "", *STI);
 452                   SS.flush();
 453                   WithColor::note()
 454                       << "instruction: " << InstructionStr << '\n';
 455                 })) {
 456           // Default case.
 457           WithColor::error() << toString(std::move(NewE));
 458         }
 459         return 1;
 460       }
 461
 462       LoweredSequence.emplace_back(std::move(Inst.get()));
 463     }
 464
 465     mca::SourceMgr S(LoweredSequence, PrintInstructionTables ? 1 : Iterations);
 466
 467     if (PrintInstructionTables) {
 468       //  Create a pipeline, stages, and a printer.
 469       auto P = llvm::make_unique<mca::Pipeline>();
 470       P->appendStage(llvm::make_unique<mca::EntryStage>(S));
 471       P->appendStage(llvm::make_unique<mca::InstructionTables>(SM));
 472       mca::PipelinePrinter Printer(*P);
 473
 474       // Create the views for this pipeline, execute, and emit a report.
 475       if (PrintInstructionInfoView) {
 476         Printer.addView(llvm::make_unique<mca::InstructionInfoView>(
 477             *STI, *MCII, Insts, *IP));
 478       }
 479       Printer.addView(
 480           llvm::make_unique<mca::ResourcePressureView>(*STI, *IP, Insts));
 481
 482       if (!runPipeline(*P))
 483         return 1;
 484
 485       Printer.printReport(TOF->os());
 486       continue;
 487     }
 488
 489     // Create a basic pipeline simulating an out-of-order backend.
 490     auto P = MCA.createDefaultPipeline(PO, IB, S);
 491     mca::PipelinePrinter Printer(*P);
 492
 493     if (PrintSummaryView)
 494       Printer.addView(
 495           llvm::make_unique<mca::SummaryView>(SM, Insts, DispatchWidth));
 496
 497     if (EnableBottleneckAnalysis) {
 498       Printer.addView(llvm::make_unique<mca::BottleneckAnalysis>(
 499           *STI, *IP, Insts, S.getNumIterations()));
 500     }
 501
 502     if (PrintInstructionInfoView)
 503       Printer.addView(
 504           llvm::make_unique<mca::InstructionInfoView>(*STI, *MCII, Insts, *IP));
 505
 506     if (PrintDispatchStats)
 507       Printer.addView(llvm::make_unique<mca::DispatchStatistics>());
 508
 509     if (PrintSchedulerStats)
 510       Printer.addView(llvm::make_unique<mca::SchedulerStatistics>(*STI));
 511
 512     if (PrintRetireStats)
 513       Printer.addView(llvm::make_unique<mca::RetireControlUnitStatistics>(SM));
 514
 515     if (PrintRegisterFileStats)
 516       Printer.addView(llvm::make_unique<mca::RegisterFileStatistics>(*STI));
 517
 518     if (PrintResourcePressureView)
 519       Printer.addView(
 520           llvm::make_unique<mca::ResourcePressureView>(*STI, *IP, Insts));
 521
 522     if (PrintTimelineView) {
 523       unsigned TimelineIterations =
 524           TimelineMaxIterations ? TimelineMaxIterations : 10;
 525       Printer.addView(llvm::make_unique<mca::TimelineView>(
 526           *STI, *IP, Insts, std::min(TimelineIterations, S.getNumIterations()),
 527           TimelineMaxCycles));
 528     }
 529
 530     if (!runPipeline(*P))
 531       return 1;
 532
 533     Printer.printReport(TOF->os());
 534
 535     // Clear the InstrBuilder internal state in preparation for another round.
 536     IB.clear();
 537   }
 538
 539   TOF->keep();
 540   return 0;
 541 }