//===-- llvm-mca.cpp - Machine Code Analyzer -------------------*- C++ -* -===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This utility is a simple driver that allows static performance analysis on // machine code similarly to how IACA (Intel Architecture Code Analyzer) works. // // llvm-mca [options] // -march // -mcpu // -o // // The target defaults to the host target. // The cpu defaults to the 'native' host cpu. // The output defaults to standard output. // //===----------------------------------------------------------------------===// #include "CodeRegion.h" #include "CodeRegionGenerator.h" #include "PipelinePrinter.h" #include "Views/BottleneckAnalysis.h" #include "Views/DispatchStatistics.h" #include "Views/InstructionInfoView.h" #include "Views/RegisterFileStatistics.h" #include "Views/ResourcePressureView.h" #include "Views/RetireControlUnitStatistics.h" #include "Views/SchedulerStatistics.h" #include "Views/SummaryView.h" #include "Views/TimelineView.h" #include "llvm/MC/MCAsmBackend.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCCodeEmitter.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCObjectFileInfo.h" #include "llvm/MC/MCRegisterInfo.h" #include "llvm/MC/MCSubtargetInfo.h" #include "llvm/MC/MCTargetOptionsCommandFlags.h" #include "llvm/MC/TargetRegistry.h" #include "llvm/MCA/CodeEmitter.h" #include "llvm/MCA/Context.h" #include "llvm/MCA/CustomBehaviour.h" #include "llvm/MCA/InstrBuilder.h" #include "llvm/MCA/Pipeline.h" #include "llvm/MCA/Stages/EntryStage.h" #include "llvm/MCA/Stages/InstructionTables.h" #include "llvm/MCA/Support.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/ErrorOr.h" #include "llvm/Support/FileSystem.h" #include "llvm/Support/Host.h" #include "llvm/Support/InitLLVM.h" #include "llvm/Support/MemoryBuffer.h" #include "llvm/Support/SourceMgr.h" #include "llvm/Support/TargetSelect.h" #include "llvm/Support/ToolOutputFile.h" #include "llvm/Support/WithColor.h" using namespace llvm; static mc::RegisterMCTargetOptionsFlags MOF; static cl::OptionCategory ToolOptions("Tool Options"); static cl::OptionCategory ViewOptions("View Options"); static cl::opt InputFilename(cl::Positional, cl::desc(""), cl::cat(ToolOptions), cl::init("-")); static cl::opt OutputFilename("o", cl::desc("Output filename"), cl::init("-"), cl::cat(ToolOptions), cl::value_desc("filename")); static cl::opt ArchName("march", cl::desc("Target architecture. " "See -version for available targets"), cl::cat(ToolOptions)); static cl::opt TripleName("mtriple", cl::desc("Target triple. See -version for available targets"), cl::cat(ToolOptions)); static cl::opt MCPU("mcpu", cl::desc("Target a specific cpu type (-mcpu=help for details)"), cl::value_desc("cpu-name"), cl::cat(ToolOptions), cl::init("native")); static cl::list MATTRS("mattr", cl::CommaSeparated, cl::desc("Target specific attributes (-mattr=help for details)"), cl::value_desc("a1,+a2,-a3,..."), cl::cat(ToolOptions)); static cl::opt PrintJson("json", cl::desc("Print the output in json format"), cl::cat(ToolOptions), cl::init(false)); static cl::opt OutputAsmVariant("output-asm-variant", cl::desc("Syntax variant to use for output printing"), cl::cat(ToolOptions), cl::init(-1)); static cl::opt PrintImmHex("print-imm-hex", cl::cat(ToolOptions), cl::init(false), cl::desc("Prefer hex format when printing immediate values")); static cl::opt Iterations("iterations", cl::desc("Number of iterations to run"), cl::cat(ToolOptions), cl::init(0)); static cl::opt DispatchWidth("dispatch", cl::desc("Override the processor dispatch width"), cl::cat(ToolOptions), cl::init(0)); static cl::opt RegisterFileSize("register-file-size", cl::desc("Maximum number of physical registers which can " "be used for register mappings"), cl::cat(ToolOptions), cl::init(0)); static cl::opt MicroOpQueue("micro-op-queue-size", cl::Hidden, cl::desc("Number of entries in the micro-op queue"), cl::cat(ToolOptions), cl::init(0)); static cl::opt DecoderThroughput("decoder-throughput", cl::Hidden, cl::desc("Maximum throughput from the decoders " "(instructions per cycle)"), cl::cat(ToolOptions), cl::init(0)); static cl::opt PrintRegisterFileStats("register-file-stats", cl::desc("Print register file statistics"), cl::cat(ViewOptions), cl::init(false)); static cl::opt PrintDispatchStats("dispatch-stats", cl::desc("Print dispatch statistics"), cl::cat(ViewOptions), cl::init(false)); static cl::opt PrintSummaryView("summary-view", cl::Hidden, cl::desc("Print summary view (enabled by default)"), cl::cat(ViewOptions), cl::init(true)); static cl::opt PrintSchedulerStats("scheduler-stats", cl::desc("Print scheduler statistics"), cl::cat(ViewOptions), cl::init(false)); static cl::opt PrintRetireStats("retire-stats", cl::desc("Print retire control unit statistics"), cl::cat(ViewOptions), cl::init(false)); static cl::opt PrintResourcePressureView( "resource-pressure", cl::desc("Print the resource pressure view (enabled by default)"), cl::cat(ViewOptions), cl::init(true)); static cl::opt PrintTimelineView("timeline", cl::desc("Print the timeline view"), cl::cat(ViewOptions), cl::init(false)); static cl::opt TimelineMaxIterations( "timeline-max-iterations", cl::desc("Maximum number of iterations to print in timeline view"), cl::cat(ViewOptions), cl::init(0)); static cl::opt TimelineMaxCycles("timeline-max-cycles", cl::desc("Maximum number of cycles in the timeline view, " "or 0 for unlimited. Defaults to 80 cycles"), cl::cat(ViewOptions), cl::init(80)); static cl::opt AssumeNoAlias("noalias", cl::desc("If set, assume that loads and stores do not alias"), cl::cat(ToolOptions), cl::init(true)); static cl::opt LoadQueueSize("lqueue", cl::desc("Size of the load queue"), cl::cat(ToolOptions), cl::init(0)); static cl::opt StoreQueueSize("squeue", cl::desc("Size of the store queue"), cl::cat(ToolOptions), cl::init(0)); static cl::opt PrintInstructionTables("instruction-tables", cl::desc("Print instruction tables"), cl::cat(ToolOptions), cl::init(false)); static cl::opt PrintInstructionInfoView( "instruction-info", cl::desc("Print the instruction info view (enabled by default)"), cl::cat(ViewOptions), cl::init(true)); static cl::opt EnableAllStats("all-stats", cl::desc("Print all hardware statistics"), cl::cat(ViewOptions), cl::init(false)); static cl::opt EnableAllViews("all-views", cl::desc("Print all views including hardware statistics"), cl::cat(ViewOptions), cl::init(false)); static cl::opt EnableBottleneckAnalysis( "bottleneck-analysis", cl::desc("Enable bottleneck analysis (disabled by default)"), cl::cat(ViewOptions), cl::init(false)); static cl::opt ShowEncoding( "show-encoding", cl::desc("Print encoding information in the instruction info view"), cl::cat(ViewOptions), cl::init(false)); static cl::opt ShowBarriers( "show-barriers", cl::desc("Print memory barrier information in the instruction info view"), cl::cat(ViewOptions), cl::init(false)); static cl::opt DisableCustomBehaviour( "disable-cb", cl::desc( "Disable custom behaviour (use the default class which does nothing)."), cl::cat(ViewOptions), cl::init(false)); namespace { const Target *getTarget(const char *ProgName) { if (TripleName.empty()) TripleName = Triple::normalize(sys::getDefaultTargetTriple()); Triple TheTriple(TripleName); // Get the target specific parser. std::string Error; const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple, Error); if (!TheTarget) { errs() << ProgName << ": " << Error; return nullptr; } // Update TripleName with the updated triple from the target lookup. TripleName = TheTriple.str(); // Return the found target. return TheTarget; } ErrorOr> getOutputStream() { if (OutputFilename == "") OutputFilename = "-"; std::error_code EC; auto Out = std::make_unique(OutputFilename, EC, sys::fs::OF_TextWithCRLF); if (!EC) return std::move(Out); return EC; } } // end of anonymous namespace static void processOptionImpl(cl::opt &O, const cl::opt &Default) { if (!O.getNumOccurrences() || O.getPosition() < Default.getPosition()) O = Default.getValue(); } static void processViewOptions(bool IsOutOfOrder) { if (!EnableAllViews.getNumOccurrences() && !EnableAllStats.getNumOccurrences()) return; if (EnableAllViews.getNumOccurrences()) { processOptionImpl(PrintSummaryView, EnableAllViews); if (IsOutOfOrder) processOptionImpl(EnableBottleneckAnalysis, EnableAllViews); processOptionImpl(PrintResourcePressureView, EnableAllViews); processOptionImpl(PrintTimelineView, EnableAllViews); processOptionImpl(PrintInstructionInfoView, EnableAllViews); } const cl::opt &Default = EnableAllViews.getPosition() < EnableAllStats.getPosition() ? EnableAllStats : EnableAllViews; processOptionImpl(PrintRegisterFileStats, Default); processOptionImpl(PrintDispatchStats, Default); processOptionImpl(PrintSchedulerStats, Default); if (IsOutOfOrder) processOptionImpl(PrintRetireStats, Default); } // Returns true on success. static bool runPipeline(mca::Pipeline &P) { // Handle pipeline errors here. Expected Cycles = P.run(); if (!Cycles) { WithColor::error() << toString(Cycles.takeError()); return false; } return true; } int main(int argc, char **argv) { InitLLVM X(argc, argv); // Initialize targets and assembly parsers. InitializeAllTargetInfos(); InitializeAllTargetMCs(); InitializeAllAsmParsers(); InitializeAllTargetMCAs(); // Enable printing of available targets when flag --version is specified. cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion); cl::HideUnrelatedOptions({&ToolOptions, &ViewOptions}); // Parse flags and initialize target options. cl::ParseCommandLineOptions(argc, argv, "llvm machine code performance analyzer.\n"); // Get the target from the triple. If a triple is not specified, then select // the default triple for the host. If the triple doesn't correspond to any // registered target, then exit with an error message. const char *ProgName = argv[0]; const Target *TheTarget = getTarget(ProgName); if (!TheTarget) return 1; // GetTarget() may replaced TripleName with a default triple. // For safety, reconstruct the Triple object. Triple TheTriple(TripleName); ErrorOr> BufferPtr = MemoryBuffer::getFileOrSTDIN(InputFilename); if (std::error_code EC = BufferPtr.getError()) { WithColor::error() << InputFilename << ": " << EC.message() << '\n'; return 1; } if (MCPU == "native") MCPU = std::string(llvm::sys::getHostCPUName()); // Package up features to be passed to target/subtarget std::string FeaturesStr; if (MATTRS.size()) { SubtargetFeatures Features; for (std::string &MAttr : MATTRS) Features.AddFeature(MAttr); FeaturesStr = Features.getString(); } std::unique_ptr STI( TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr)); assert(STI && "Unable to create subtarget info!"); if (!STI->isCPUStringValid(MCPU)) return 1; if (!STI->getSchedModel().hasInstrSchedModel()) { WithColor::error() << "unable to find instruction-level scheduling information for" << " target triple '" << TheTriple.normalize() << "' and cpu '" << MCPU << "'.\n"; if (STI->getSchedModel().InstrItineraries) WithColor::note() << "cpu '" << MCPU << "' provides itineraries. However, " << "instruction itineraries are currently unsupported.\n"; return 1; } // Apply overrides to llvm-mca specific options. bool IsOutOfOrder = STI->getSchedModel().isOutOfOrder(); processViewOptions(IsOutOfOrder); std::unique_ptr MRI(TheTarget->createMCRegInfo(TripleName)); assert(MRI && "Unable to create target register info!"); MCTargetOptions MCOptions = mc::InitMCTargetOptionsFromFlags(); std::unique_ptr MAI( TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions)); assert(MAI && "Unable to create target asm info!"); SourceMgr SrcMgr; // Tell SrcMgr about this buffer, which is what the parser will pick up. SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc()); MCContext Ctx(TheTriple, MAI.get(), MRI.get(), STI.get(), &SrcMgr); std::unique_ptr MOFI( TheTarget->createMCObjectFileInfo(Ctx, /*PIC=*/false)); Ctx.setObjectFileInfo(MOFI.get()); std::unique_ptr BOS; std::unique_ptr MCII(TheTarget->createMCInstrInfo()); assert(MCII && "Unable to create instruction info!"); std::unique_ptr MCIA( TheTarget->createMCInstrAnalysis(MCII.get())); // Need to initialize an MCInstPrinter as it is // required for initializing the MCTargetStreamer // which needs to happen within the CRG.parseCodeRegions() call below. // Without an MCTargetStreamer, certain assembly directives can trigger a // segfault. (For example, the .cv_fpo_proc directive on x86 will segfault if // we don't initialize the MCTargetStreamer.) unsigned IPtempOutputAsmVariant = OutputAsmVariant == -1 ? 0 : OutputAsmVariant; std::unique_ptr IPtemp(TheTarget->createMCInstPrinter( Triple(TripleName), IPtempOutputAsmVariant, *MAI, *MCII, *MRI)); if (!IPtemp) { WithColor::error() << "unable to create instruction printer for target triple '" << TheTriple.normalize() << "' with assembly variant " << IPtempOutputAsmVariant << ".\n"; return 1; } // Parse the input and create CodeRegions that llvm-mca can analyze. mca::AsmCodeRegionGenerator CRG(*TheTarget, SrcMgr, Ctx, *MAI, *STI, *MCII); Expected RegionsOrErr = CRG.parseCodeRegions(std::move(IPtemp)); if (!RegionsOrErr) { if (auto Err = handleErrors(RegionsOrErr.takeError(), [](const StringError &E) { WithColor::error() << E.getMessage() << '\n'; })) { // Default case. WithColor::error() << toString(std::move(Err)) << '\n'; } return 1; } const mca::CodeRegions &Regions = *RegionsOrErr; // Early exit if errors were found by the code region parsing logic. if (!Regions.isValid()) return 1; if (Regions.empty()) { WithColor::error() << "no assembly instructions found.\n"; return 1; } // Now initialize the output file. auto OF = getOutputStream(); if (std::error_code EC = OF.getError()) { WithColor::error() << EC.message() << '\n'; return 1; } unsigned AssemblerDialect = CRG.getAssemblerDialect(); if (OutputAsmVariant >= 0) AssemblerDialect = static_cast(OutputAsmVariant); std::unique_ptr IP(TheTarget->createMCInstPrinter( Triple(TripleName), AssemblerDialect, *MAI, *MCII, *MRI)); if (!IP) { WithColor::error() << "unable to create instruction printer for target triple '" << TheTriple.normalize() << "' with assembly variant " << AssemblerDialect << ".\n"; return 1; } // Set the display preference for hex vs. decimal immediates. IP->setPrintImmHex(PrintImmHex); std::unique_ptr TOF = std::move(*OF); const MCSchedModel &SM = STI->getSchedModel(); std::unique_ptr IPP; if (!DisableCustomBehaviour) { // TODO: It may be a good idea to separate CB and IPP so that they can // be used independently of each other. What I mean by this is to add // an extra command-line arg --disable-ipp so that CB and IPP can be // toggled without needing to toggle both of them together. IPP = std::unique_ptr( TheTarget->createInstrPostProcess(*STI, *MCII)); } if (!IPP) { // If the target doesn't have its own IPP implemented (or the -disable-cb // flag is set) then we use the base class (which does nothing). IPP = std::make_unique(*STI, *MCII); } // Create an instruction builder. mca::InstrBuilder IB(*STI, *MCII, *MRI, MCIA.get()); // Create a context to control ownership of the pipeline hardware. mca::Context MCA(*MRI, *STI); mca::PipelineOptions PO(MicroOpQueue, DecoderThroughput, DispatchWidth, RegisterFileSize, LoadQueueSize, StoreQueueSize, AssumeNoAlias, EnableBottleneckAnalysis); // Number each region in the sequence. unsigned RegionIdx = 0; std::unique_ptr MCE( TheTarget->createMCCodeEmitter(*MCII, Ctx)); assert(MCE && "Unable to create code emitter!"); std::unique_ptr MAB(TheTarget->createMCAsmBackend( *STI, *MRI, mc::InitMCTargetOptionsFromFlags())); assert(MAB && "Unable to create asm backend!"); json::Object JSONOutput; for (const std::unique_ptr &Region : Regions) { // Skip empty code regions. if (Region->empty()) continue; IB.clear(); // Lower the MCInst sequence into an mca::Instruction sequence. ArrayRef Insts = Region->getInstructions(); mca::CodeEmitter CE(*STI, *MAB, *MCE, Insts); IPP->resetState(); SmallVector> LoweredSequence; for (const MCInst &MCI : Insts) { Expected> Inst = IB.createInstruction(MCI); if (!Inst) { if (auto NewE = handleErrors( Inst.takeError(), [&IP, &STI](const mca::InstructionError &IE) { std::string InstructionStr; raw_string_ostream SS(InstructionStr); WithColor::error() << IE.Message << '\n'; IP->printInst(&IE.Inst, 0, "", *STI, SS); SS.flush(); WithColor::note() << "instruction: " << InstructionStr << '\n'; })) { // Default case. WithColor::error() << toString(std::move(NewE)); } return 1; } IPP->postProcessInstruction(Inst.get(), MCI); LoweredSequence.emplace_back(std::move(Inst.get())); } mca::CircularSourceMgr S(LoweredSequence, PrintInstructionTables ? 1 : Iterations); if (PrintInstructionTables) { // Create a pipeline, stages, and a printer. auto P = std::make_unique(); P->appendStage(std::make_unique(S)); P->appendStage(std::make_unique(SM)); mca::PipelinePrinter Printer(*P, *Region, RegionIdx, *STI, PO); if (PrintJson) { Printer.addView( std::make_unique(*STI, *IP, Insts)); } // Create the views for this pipeline, execute, and emit a report. if (PrintInstructionInfoView) { Printer.addView(std::make_unique( *STI, *MCII, CE, ShowEncoding, Insts, *IP, LoweredSequence, ShowBarriers)); } Printer.addView( std::make_unique(*STI, *IP, Insts)); if (!runPipeline(*P)) return 1; if (PrintJson) { Printer.printReport(JSONOutput); } else { Printer.printReport(TOF->os()); } ++RegionIdx; continue; } // Create the CustomBehaviour object for enforcing Target Specific // behaviours and dependencies that aren't expressed well enough // in the tablegen. CB cannot depend on the list of MCInst or // the source code (but it can depend on the list of // mca::Instruction or any objects that can be reconstructed // from the target information). std::unique_ptr CB; if (!DisableCustomBehaviour) CB = std::unique_ptr( TheTarget->createCustomBehaviour(*STI, S, *MCII)); if (!CB) // If the target doesn't have its own CB implemented (or the -disable-cb // flag is set) then we use the base class (which does nothing). CB = std::make_unique(*STI, S, *MCII); // Create a basic pipeline simulating an out-of-order backend. auto P = MCA.createDefaultPipeline(PO, S, *CB); mca::PipelinePrinter Printer(*P, *Region, RegionIdx, *STI, PO); // Targets can define their own custom Views that exist within their // /lib/Target/ directory so that the View can utilize their CustomBehaviour // or other backend symbols / functionality that are not already exposed // through one of the MC-layer classes. These Views will be initialized // using the CustomBehaviour::getViews() variants. // If a target makes a custom View that does not depend on their target // CB or their backend, they should put the View within // /tools/llvm-mca/Views/ instead. if (!DisableCustomBehaviour) { std::vector> CBViews = CB->getStartViews(*IP, Insts); for (auto &CBView : CBViews) Printer.addView(std::move(CBView)); } // When we output JSON, we add a view that contains the instructions // and CPU resource information. if (PrintJson) { auto IV = std::make_unique(*STI, *IP, Insts); Printer.addView(std::move(IV)); } if (PrintSummaryView) Printer.addView( std::make_unique(SM, Insts, DispatchWidth)); if (EnableBottleneckAnalysis) { if (!IsOutOfOrder) { WithColor::warning() << "bottleneck analysis is not supported for in-order CPU '" << MCPU << "'.\n"; } Printer.addView(std::make_unique( *STI, *IP, Insts, S.getNumIterations())); } if (PrintInstructionInfoView) Printer.addView(std::make_unique( *STI, *MCII, CE, ShowEncoding, Insts, *IP, LoweredSequence, ShowBarriers)); // Fetch custom Views that are to be placed after the InstructionInfoView. // Refer to the comment paired with the CB->getStartViews(*IP, Insts); line // for more info. if (!DisableCustomBehaviour) { std::vector> CBViews = CB->getPostInstrInfoViews(*IP, Insts); for (auto &CBView : CBViews) Printer.addView(std::move(CBView)); } if (PrintDispatchStats) Printer.addView(std::make_unique()); if (PrintSchedulerStats) Printer.addView(std::make_unique(*STI)); if (PrintRetireStats) Printer.addView(std::make_unique(SM)); if (PrintRegisterFileStats) Printer.addView(std::make_unique(*STI)); if (PrintResourcePressureView) Printer.addView( std::make_unique(*STI, *IP, Insts)); if (PrintTimelineView) { unsigned TimelineIterations = TimelineMaxIterations ? TimelineMaxIterations : 10; Printer.addView(std::make_unique( *STI, *IP, Insts, std::min(TimelineIterations, S.getNumIterations()), TimelineMaxCycles)); } // Fetch custom Views that are to be placed after all other Views. // Refer to the comment paired with the CB->getStartViews(*IP, Insts); line // for more info. if (!DisableCustomBehaviour) { std::vector> CBViews = CB->getEndViews(*IP, Insts); for (auto &CBView : CBViews) Printer.addView(std::move(CBView)); } if (!runPipeline(*P)) return 1; if (PrintJson) { Printer.printReport(JSONOutput); } else { Printer.printReport(TOF->os()); } ++RegionIdx; } if (PrintJson) TOF->os() << formatv("{0:2}", json::Value(std::move(JSONOutput))) << "\n"; TOF->keep(); return 0; }