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