//===- llvm-profgen.cpp - LLVM SPGO profile generation tool -----*- 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
//
//===----------------------------------------------------------------------===//
//
// llvm-profgen generates SPGO profiles from perf script ouput.
//
//===----------------------------------------------------------------------===//

#include "ErrorHandling.h"
#include "Options.h"
#include "PerfReader.h"
#include "ProfileGenerator.h"
#include "ProfiledBinary.h"
#include "llvm/DebugInfo/Symbolize/SymbolizableModule.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/VirtualFileSystem.h"

using namespace llvm;
using namespace sampleprof;

namespace llvm {

cl::OptionCategory ProfGenCategory("ProfGen Options");

static cl::opt<std::string> PerfScriptFilename(
    "perfscript", cl::value_desc("perfscript"),
    cl::desc("Path of perf-script trace created by Linux perf tool with "
             "`script` command(the raw perf.data should be profiled with -b). "
             "Cannot be used with --perfdata, --unsymbolized-profile, or "
             "--llvm-sample-profile."),
    cl::cat(ProfGenCategory));
static cl::alias PSA("ps", cl::desc("Alias for --perfscript"),
                     cl::aliasopt(PerfScriptFilename));

static cl::opt<std::string> PerfDataFilename(
    "perfdata", cl::value_desc("perfdata"),
    cl::desc("Path of raw perf data created by Linux perf tool (it should be "
             "profiled with -b). Cannot be used with --perfscript, "
             "--unsymbolized-profile, or --llvm-sample-profile."),
    cl::cat(ProfGenCategory));
static cl::alias PDA("pd", cl::desc("Alias for --perfdata"),
                     cl::aliasopt(PerfDataFilename));

static cl::opt<std::string> UnsymbolizedProfFilename(
    "unsymbolized-profile", cl::value_desc("unsymbolized profile"),
    cl::desc("Path of the unsymbolized profile created by "
             "`llvm-profgen` with `--skip-symbolization`. "
             "Cannot be used with --perfscript, --perfdata, or "
             "--llvm-sample-profile."),
    cl::cat(ProfGenCategory));
static cl::alias UPA("up", cl::desc("Alias for --unsymbolized-profile"),
                     cl::aliasopt(UnsymbolizedProfFilename));

static cl::opt<std::string> SampleProfFilename(
    "llvm-sample-profile", cl::value_desc("llvm sample profile"),
    cl::desc("Path of the LLVM sample profile. Cannot be used with"
             "--perfscript, --perfdata, or --unsymbolized-profile"),
    cl::cat(ProfGenCategory));

static cl::opt<std::string>
    BinaryPath("binary", cl::value_desc("binary"), cl::Required,
               cl::desc("Path of profiled executable binary."),
               cl::cat(ProfGenCategory));

static cl::opt<uint32_t>
    ProcessId("pid", cl::value_desc("process Id"), cl::init(0),
              cl::desc("Process Id for the profiled executable binary."),
              cl::cat(ProfGenCategory));

static cl::opt<std::string> DebugBinPath(
    "debug-binary", cl::value_desc("debug-binary"),
    cl::desc("Path of debug info binary, llvm-profgen will load the DWARF info "
             "from it instead of the executable binary."),
    cl::cat(ProfGenCategory));

static cl::opt<std::string> DataAccessProfileFilename(
    "data-access-perftrace", cl::value_desc("data-access-perftrace"),
    cl::desc("File path of a Linux perf raw trace (generated by `perf report "
             "-D`) consisting of memory access events."),
    cl::cat(ProfGenCategory));

static cl::opt<std::string> ETMPath("etm", cl::value_desc("etm"),
                                    cl::desc("Path of raw ETM trace file"),
                                    cl::cat(ProfGenCategory));

static cl::opt<unsigned> ETMTraceID(
    "etm-trace-id", cl::init(0x10),
    cl::desc("CoreSight Trace ID (CSID) used to route ETM trace data."),
    cl::cat(ProfGenCategory));

static cl::opt<std::string>
    TargetTriple("target-triple", cl::value_desc("triple"),
                 cl::desc("Override the target triple for the binary"),
                 cl::cat(ProfGenCategory));

// Validate the command line input.
static void validateCommandLine() {
  // Allow the missing perfscript if we only use to show binary disassembly.
  if (!ShowDisassemblyOnly) {
    // Validate input profile is provided only once
    bool HasPerfData = PerfDataFilename.getNumOccurrences() > 0;
    bool HasPerfScript = PerfScriptFilename.getNumOccurrences() > 0;
    bool HasUnsymbolizedProfile =
        UnsymbolizedProfFilename.getNumOccurrences() > 0;
    bool HasSampleProfile = SampleProfFilename.getNumOccurrences() > 0;
    bool HasEtm = ETMPath.getNumOccurrences() > 0;
    uint16_t S = HasPerfData + HasPerfScript + HasUnsymbolizedProfile +
                 HasSampleProfile + HasEtm;
    if (S != 1) {
      std::string Msg =
          S > 1 ? "Only one of `--perfscript`, `--perfdata`, "
                  "`--unsymbolized-profile`, "
                  "`--sample-profile` or `--etm` can be used."
                : "Perf input file is missing. Please provide one of "
                  "`--perfscript`, "
                  "`--perfdata`, `--unsymbolized-profile`, `--sample-profile`, "
                  "`--etm`.";
      exitWithError(Msg);
    }

    auto CheckFileExists = [](bool H, StringRef File) {
      if (H && !llvm::sys::fs::exists(File)) {
        std::string Msg = "Input perf file(" + File.str() + ") doesn't exist.";
        exitWithError(Msg);
      }
    };

    CheckFileExists(HasPerfData, PerfDataFilename);
    CheckFileExists(HasPerfScript, PerfScriptFilename);
    CheckFileExists(HasUnsymbolizedProfile, UnsymbolizedProfFilename);
    CheckFileExists(HasSampleProfile, SampleProfFilename);
    CheckFileExists(HasEtm, ETMPath);
  }

  if (!llvm::sys::fs::exists(BinaryPath)) {
    std::string Msg = "Input binary(" + BinaryPath + ") doesn't exist.";
    exitWithError(Msg);
  }

  if (CSProfileGenerator::MaxCompressionSize < -1) {
    exitWithError("Value of --compress-recursion should >= -1");
  }
  if (ShowSourceLocations && !ShowDisassemblyOnly) {
    exitWithError("--show-source-locations should work together with "
                  "--show-disassembly-only!");
  }
}

static InputFile getInputFile() {
  InputFile File;
  if (PerfDataFilename.getNumOccurrences()) {
    File.InputFilePath = PerfDataFilename;
    File.Format = InputFormat::PerfData;
  } else if (PerfScriptFilename.getNumOccurrences()) {
    File.InputFilePath = PerfScriptFilename;
    File.Format = InputFormat::PerfScript;
  } else if (UnsymbolizedProfFilename.getNumOccurrences()) {
    File.InputFilePath = UnsymbolizedProfFilename;
    File.Format = InputFormat::UnsymbolizedProfile;
  } else if (ETMPath.getNumOccurrences()) {
    File.InputFilePath = ETMPath;
    File.Format = InputFormat::ETMFormat;
  }
  return File;
}

} // end namespace llvm

int main(int argc, const char *argv[]) {
  InitLLVM X(argc, argv);

  // Initialize targets and assembly printers/parsers.
  InitializeAllTargetInfos();
  InitializeAllTargetMCs();
  InitializeAllDisassemblers();

  cl::HideUnrelatedOptions({&ProfGenCategory, &getColorCategory()});
  cl::ParseCommandLineOptions(argc, argv, "llvm SPGO profile generator\n");
  validateCommandLine();

  // Load symbols and disassemble the code of a given binary.
  std::unique_ptr<ProfiledBinary> Binary =
      std::make_unique<ProfiledBinary>(BinaryPath, DebugBinPath);
  Binary->load(TargetTriple);

  if (ShowDisassemblyOnly)
    return EXIT_SUCCESS;

  if (SampleProfFilename.getNumOccurrences()) {
    LLVMContext Context;
    auto FS = vfs::getRealFileSystem();
    auto ReaderOrErr =
        SampleProfileReader::create(SampleProfFilename, Context, *FS);
    if (std::error_code EC = ReaderOrErr.getError())
      exitWithError(EC, SampleProfFilename);
    std::unique_ptr<sampleprof::SampleProfileReader> Reader =
        std::move(ReaderOrErr.get());
    Reader->read();
    std::unique_ptr<ProfileGeneratorBase> Generator =
        ProfileGeneratorBase::create(Binary.get(), Reader->getProfiles(),
                                     Reader->profileIsCS());
    Generator->generateProfile();
    Generator->write();
  } else {
    std::optional<uint32_t> PIDFilter;
    if (ProcessId.getNumOccurrences())
      PIDFilter = ProcessId;
    InputFile File = getInputFile();
    const ContextSampleCounterMap *Counters = nullptr;
    bool ProfileIsCS = false;
    std::unique_ptr<ETMReader> EtmReader;
    std::unique_ptr<PerfReaderBase> PerfReader;

    if (File.Format == InputFormat::ETMFormat) {
      EtmReader = std::make_unique<ETMReader>(Binary.get(), File.InputFilePath,
                                              static_cast<uint8_t>(ETMTraceID));
      EtmReader->parseETMTraces();
      Counters = &EtmReader->getSampleCounters();
    } else {
      PerfReader = PerfReaderBase::create(Binary.get(), File, PIDFilter);
      // Parse perf events and samples
      PerfReader->parsePerfTraces();

      if (!DataAccessProfileFilename.empty()) {
        if (PerfReader->profileIsCS() || Binary->usePseudoProbes()) {
          exitWithError("Symbolizing vtables from data access profiles is not "
                        "yet supported for context-sensitive perf traces or "
                        "when pseudo-probe based mapping is enabled. ");
        }
        // Parse the data access perf traces into <ip, data-addr> pairs,
        // symbolize the data-addr to data-symbol. If the data-addr is a vtable,
        // increment counters for the <ip, data-symbol> pair.
        if (Error E = PerfReader->parseDataAccessPerfTraces(
                DataAccessProfileFilename, PIDFilter)) {
          handleAllErrors(std::move(E), [&](const StringError &SE) {
            exitWithError(SE.getMessage());
          });
        }
      }
      Counters = &PerfReader->getSampleCounters();
      ProfileIsCS = PerfReader->profileIsCS();
    }

    if (SkipSymbolization)
      return EXIT_SUCCESS;

    std::unique_ptr<ProfileGeneratorBase> Generator =
        ProfileGeneratorBase::create(Binary.get(), Counters, ProfileIsCS);
    Generator->generateProfile();
    Generator->write();
  }

  return EXIT_SUCCESS;
}