//===-- Timer.cpp - Interval Timing Support -------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Interval Timing implementation.
//
//===----------------------------------------------------------------------===//

#include "llvm/Support/Debug.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Format.h"
#include "llvm/System/Process.h"
#include <algorithm>
#include <functional>
#include <map>
using namespace llvm;

// GetLibSupportInfoOutputFile - Return a file stream to print our output on.
namespace llvm { extern raw_ostream *GetLibSupportInfoOutputFile(); }

// getLibSupportInfoOutputFilename - This ugly hack is brought to you courtesy
// of constructor/destructor ordering being unspecified by C++.  Basically the
// problem is that a Statistic object gets destroyed, which ends up calling
// 'GetLibSupportInfoOutputFile()' (below), which calls this function.
// LibSupportInfoOutputFilename used to be a global variable, but sometimes it
// would get destroyed before the Statistic, causing havoc to ensue.  We "fix"
// this by creating the string the first time it is needed and never destroying
// it.
static ManagedStatic<std::string> LibSupportInfoOutputFilename;
static std::string &getLibSupportInfoOutputFilename() {
  return *LibSupportInfoOutputFilename;
}

static ManagedStatic<sys::SmartMutex<true> > TimerLock;

namespace {
  static cl::opt<bool>
  TrackSpace("track-memory", cl::desc("Enable -time-passes memory "
                                      "tracking (this may be slow)"),
             cl::Hidden);

  static cl::opt<std::string, true>
  InfoOutputFilename("info-output-file", cl::value_desc("filename"),
                     cl::desc("File to append -stats and -timer output to"),
                   cl::Hidden, cl::location(getLibSupportInfoOutputFilename()));
}

static TimerGroup *DefaultTimerGroup = 0;
static TimerGroup *getDefaultTimerGroup() {
  TimerGroup *tmp = DefaultTimerGroup;
  sys::MemoryFence();
  if (tmp) return tmp;
  
  llvm_acquire_global_lock();
  tmp = DefaultTimerGroup;
  if (!tmp) {
    tmp = new TimerGroup("Miscellaneous Ungrouped Timers");
    sys::MemoryFence();
    DefaultTimerGroup = tmp;
  }
  llvm_release_global_lock();

  return tmp;
}

//===----------------------------------------------------------------------===//
// Timer Implementation
//===----------------------------------------------------------------------===//

Timer::Timer(const std::string &N)
  : Elapsed(0), UserTime(0), SystemTime(0), MemUsed(0), PeakMem(0), Name(N),
    Started(false), TG(getDefaultTimerGroup()) {
  TG->addTimer();
}

Timer::Timer(const std::string &N, TimerGroup &tg)
  : Elapsed(0), UserTime(0), SystemTime(0), MemUsed(0), PeakMem(0), Name(N),
    Started(false), TG(&tg) {
  TG->addTimer();
}

Timer::Timer(const Timer &T) {
  TG = T.TG;
  if (TG) TG->addTimer();
  operator=(T);
}

// Copy ctor, initialize with no TG member.
Timer::Timer(bool, const Timer &T) {
  TG = T.TG;     // Avoid assertion in operator=
  operator=(T);  // Copy contents
  TG = 0;
}

Timer::~Timer() {
  if (!TG) return;
  
  if (Started) {
    Started = false;
    TG->addTimerToPrint(*this);
  }
  TG->removeTimer();
}

static inline size_t getMemUsage() {
  if (TrackSpace)
    return sys::Process::GetMallocUsage();
  return 0;
}

struct TimeRecord {
  double Elapsed, UserTime, SystemTime;
  ssize_t MemUsed;
};

static TimeRecord getTimeRecord(bool Start) {
  TimeRecord Result;

  sys::TimeValue now(0,0);
  sys::TimeValue user(0,0);
  sys::TimeValue sys(0,0);

  ssize_t MemUsed = 0;
  if (Start) {
    MemUsed = getMemUsage();
    sys::Process::GetTimeUsage(now, user, sys);
  } else {
    sys::Process::GetTimeUsage(now, user, sys);
    MemUsed = getMemUsage();
  }

  Result.Elapsed    =  now.seconds()  + now.microseconds() / 1000000.0;
  Result.UserTime   = user.seconds() + user.microseconds() / 1000000.0;
  Result.SystemTime =  sys.seconds()  + sys.microseconds() / 1000000.0;
  Result.MemUsed = MemUsed;
  return Result;
}

static ManagedStatic<std::vector<Timer*> > ActiveTimers;

void Timer::startTimer() {
  Started = true;
  ActiveTimers->push_back(this);
  TimeRecord TR = getTimeRecord(true);
  Elapsed    -= TR.Elapsed;
  UserTime   -= TR.UserTime;
  SystemTime -= TR.SystemTime;
  MemUsed    -= TR.MemUsed;
  PeakMemBase = TR.MemUsed;
}

void Timer::stopTimer() {
  TimeRecord TR = getTimeRecord(false);
  Elapsed    += TR.Elapsed;
  UserTime   += TR.UserTime;
  SystemTime += TR.SystemTime;
  MemUsed    += TR.MemUsed;

  if (ActiveTimers->back() == this) {
    ActiveTimers->pop_back();
  } else {
    std::vector<Timer*>::iterator I =
      std::find(ActiveTimers->begin(), ActiveTimers->end(), this);
    assert(I != ActiveTimers->end() && "stop but no startTimer?");
    ActiveTimers->erase(I);
  }
}

void Timer::sum(const Timer &T) {
  Elapsed    += T.Elapsed;
  UserTime   += T.UserTime;
  SystemTime += T.SystemTime;
  MemUsed    += T.MemUsed;
  PeakMem    += T.PeakMem;
}

const Timer &Timer::operator=(const Timer &T) {
  Elapsed = T.Elapsed;
  UserTime = T.UserTime;
  SystemTime = T.SystemTime;
  MemUsed = T.MemUsed;
  PeakMem = T.PeakMem;
  PeakMemBase = T.PeakMemBase;
  Name = T.Name;
  Started = T.Started;
  assert(TG == T.TG && "Can only assign timers in the same TimerGroup!");
  return *this;
}


/// addPeakMemoryMeasurement - This method should be called whenever memory
/// usage needs to be checked.  It adds a peak memory measurement to the
/// currently active timers, which will be printed when the timer group prints
///
void Timer::addPeakMemoryMeasurement() {
  size_t MemUsed = getMemUsage();
  for (std::vector<Timer*>::iterator I = ActiveTimers->begin(),
         E = ActiveTimers->end(); I != E; ++I)
    (*I)->PeakMem = std::max((*I)->PeakMem, MemUsed-(*I)->PeakMemBase);
}


static void printVal(double Val, double Total, raw_ostream &OS) {
  if (Total < 1e-7)   // Avoid dividing by zero.
    OS << "        -----     ";
  else {
    OS << "  " << format("%7.4f", Val) << " (";
    OS << format("%5.1f", Val*100/Total) << "%)";
  }
}

void Timer::print(const Timer &Total, raw_ostream &OS) {
  if (Total.UserTime)
    printVal(UserTime, Total.UserTime, OS);
  if (Total.SystemTime)
    printVal(SystemTime, Total.SystemTime, OS);
  if (Total.getProcessTime())
    printVal(getProcessTime(), Total.getProcessTime(), OS);
  printVal(Elapsed, Total.Elapsed, OS);
  
  OS << "  ";
  
  if (Total.MemUsed)
    OS << format("%9lld", (long long)MemUsed) << "  ";

  if (Total.PeakMem) {
    if (PeakMem)
      OS << format("%9lld", (long long)PeakMem) << "  ";
    else
      OS << "           ";
  }
  OS << Name << "\n";
  
  Started = false;  // Once printed, don't print again
}


//===----------------------------------------------------------------------===//
//   NamedRegionTimer Implementation
//===----------------------------------------------------------------------===//

typedef std::map<std::string, Timer> Name2Timer;
typedef std::map<std::string, std::pair<TimerGroup, Name2Timer> > Name2Pair;

static ManagedStatic<Name2Timer> NamedTimers;
static ManagedStatic<Name2Pair> NamedGroupedTimers;

static Timer &getNamedRegionTimer(const std::string &Name) {
  sys::SmartScopedLock<true> L(*TimerLock);
  Name2Timer::iterator I = NamedTimers->find(Name);
  if (I != NamedTimers->end())
    return I->second;

  return NamedTimers->insert(I, std::make_pair(Name, Timer(Name)))->second;
}

static Timer &getNamedRegionTimer(const std::string &Name,
                                  const std::string &GroupName) {
  sys::SmartScopedLock<true> L(*TimerLock);

  Name2Pair::iterator I = NamedGroupedTimers->find(GroupName);
  if (I == NamedGroupedTimers->end()) {
    TimerGroup TG(GroupName);
    std::pair<TimerGroup, Name2Timer> Pair(TG, Name2Timer());
    I = NamedGroupedTimers->insert(I, std::make_pair(GroupName, Pair));
  }

  Name2Timer::iterator J = I->second.second.find(Name);
  if (J == I->second.second.end())
    J = I->second.second.insert(J,
                                std::make_pair(Name,
                                               Timer(Name,
                                                     I->second.first)));

  return J->second;
}

NamedRegionTimer::NamedRegionTimer(const std::string &Name)
  : TimeRegion(getNamedRegionTimer(Name)) {}

NamedRegionTimer::NamedRegionTimer(const std::string &Name,
                                   const std::string &GroupName)
  : TimeRegion(getNamedRegionTimer(Name, GroupName)) {}

//===----------------------------------------------------------------------===//
//   TimerGroup Implementation
//===----------------------------------------------------------------------===//

// GetLibSupportInfoOutputFile - Return a file stream to print our output on.
raw_ostream *llvm::GetLibSupportInfoOutputFile() {
  std::string &LibSupportInfoOutputFilename = getLibSupportInfoOutputFilename();
  if (LibSupportInfoOutputFilename.empty())
    return &errs();
  if (LibSupportInfoOutputFilename == "-")
    return &outs();

  std::string Error;
  raw_ostream *Result = new raw_fd_ostream(LibSupportInfoOutputFilename.c_str(),
                                           Error, raw_fd_ostream::F_Append);
  if (Error.empty())
    return Result;

  errs() << "Error opening info-output-file '"
         << LibSupportInfoOutputFilename << " for appending!\n";
  delete Result;
  return &errs();
}


void TimerGroup::removeTimer() {
  sys::SmartScopedLock<true> L(*TimerLock);
  if (--NumTimers != 0 || TimersToPrint.empty())
    return; // Don't print timing report.
  
  // Sort the timers in descending order by amount of time taken.
  std::sort(TimersToPrint.begin(), TimersToPrint.end(),
            std::greater<Timer>());

  // Figure out how many spaces to indent TimerGroup name.
  unsigned Padding = (80-Name.length())/2;
  if (Padding > 80) Padding = 0;         // Don't allow "negative" numbers

  raw_ostream *OutStream = GetLibSupportInfoOutputFile();

  ++NumTimers;
  {  // Scope to contain Total timer: don't allow total timer to drop us to
     // zero timers.
    Timer Total("TOTAL");

    for (unsigned i = 0, e = TimersToPrint.size(); i != e; ++i)
      Total.sum(TimersToPrint[i]);

    // Print out timing header.
    *OutStream << "===" << std::string(73, '-') << "===\n"
               << std::string(Padding, ' ') << Name << "\n"
               << "===" << std::string(73, '-')
               << "===\n";

    // If this is not an collection of ungrouped times, print the total time.
    // Ungrouped timers don't really make sense to add up.  We still print the
    // TOTAL line to make the percentages make sense.
    if (this != DefaultTimerGroup) {
      *OutStream << "  Total Execution Time: ";

      *OutStream << format("%5.4f", Total.getProcessTime()) << " seconds (";
      *OutStream << format("%5.4f", Total.getWallTime()) << " wall clock)\n";
    }
    *OutStream << "\n";

    if (Total.UserTime)
      *OutStream << "   ---User Time---";
    if (Total.SystemTime)
      *OutStream << "   --System Time--";
    if (Total.getProcessTime())
      *OutStream << "   --User+System--";
    *OutStream << "   ---Wall Time---";
    if (Total.getMemUsed())
      *OutStream << "  ---Mem---";
    if (Total.getPeakMem())
      *OutStream << "  -PeakMem-";
    *OutStream << "  --- Name ---\n";

    // Loop through all of the timing data, printing it out.
    for (unsigned i = 0, e = TimersToPrint.size(); i != e; ++i)
      TimersToPrint[i].print(Total, *OutStream);

    Total.print(Total, *OutStream);
    *OutStream << '\n';
    OutStream->flush();
  }
  --NumTimers;

  TimersToPrint.clear();

  if (OutStream != &errs() && OutStream != &outs())
    delete OutStream;   // Close the file.
}

void TimerGroup::addTimer() {
  sys::SmartScopedLock<true> L(*TimerLock);
  ++NumTimers;
}

void TimerGroup::addTimerToPrint(const Timer &T) {
  sys::SmartScopedLock<true> L(*TimerLock);
  TimersToPrint.push_back(Timer(true, T));
}